From c167b9c7e3d6131b4a4865c112a3dbc86d2e997d Mon Sep 17 00:00:00 2001 From: Maximilian Luz Date: Mon, 21 Dec 2020 19:39:51 +0100 Subject: platform/surface: Add Surface Aggregator subsystem Add Surface System Aggregator Module core and Surface Serial Hub driver, required for the embedded controller found on Microsoft Surface devices. The Surface System Aggregator Module (SSAM, SAM or Surface Aggregator) is an embedded controller (EC) found on 4th and later generation Microsoft Surface devices, with the exception of the Surface Go series. This EC provides various functionality, depending on the device in question. This can include battery status and thermal reporting (5th and later generations), but also HID keyboard (6th+) and touchpad input (7th+) on Surface Laptop and Surface Book 3 series devices. This patch provides the basic necessities for communication with the SAM EC on 5th and later generation devices. On these devices, the EC provides an interface that acts as serial device, called the Surface Serial Hub (SSH). 4th generation devices, on which the EC interface is provided via an HID-over-I2C device, are not supported by this patch. Specifically, this patch adds a driver for the SSH device (device HID MSHW0084 in ACPI), as well as a controller structure and associated API. This represents the functional core of the Surface Aggregator kernel subsystem, introduced with this patch, and will be expanded upon in subsequent commits. The SSH driver acts as the main attachment point for this subsystem and sets-up and manages the controller structure. The controller in turn provides a basic communication interface, allowing to send requests from host to EC and receiving the corresponding responses, as well as managing and receiving events, sent from EC to host. It is structured into multiple layers, with the top layer presenting the API used by other kernel drivers and the lower layers modeled after the serial protocol used for communication. Said other drivers are then responsible for providing the (Surface model specific) functionality accessible through the EC (e.g. battery status reporting, thermal information, ...) via said controller structure and API, and will be added in future commits. Signed-off-by: Maximilian Luz Link: https://lore.kernel.org/r/20201221183959.1186143-2-luzmaximilian@gmail.com Signed-off-by: Hans de Goede --- drivers/platform/surface/Kconfig | 2 + drivers/platform/surface/Makefile | 1 + drivers/platform/surface/aggregator/Kconfig | 42 + drivers/platform/surface/aggregator/Makefile | 10 + drivers/platform/surface/aggregator/controller.c | 2504 ++++++++++++++++++++ drivers/platform/surface/aggregator/controller.h | 276 +++ drivers/platform/surface/aggregator/core.c | 787 ++++++ drivers/platform/surface/aggregator/ssh_msgb.h | 205 ++ .../platform/surface/aggregator/ssh_packet_layer.c | 1710 +++++++++++++ .../platform/surface/aggregator/ssh_packet_layer.h | 187 ++ drivers/platform/surface/aggregator/ssh_parser.c | 228 ++ drivers/platform/surface/aggregator/ssh_parser.h | 154 ++ .../surface/aggregator/ssh_request_layer.c | 1211 ++++++++++ .../surface/aggregator/ssh_request_layer.h | 143 ++ 14 files changed, 7460 insertions(+) create mode 100644 drivers/platform/surface/aggregator/Kconfig create mode 100644 drivers/platform/surface/aggregator/Makefile create mode 100644 drivers/platform/surface/aggregator/controller.c create mode 100644 drivers/platform/surface/aggregator/controller.h create mode 100644 drivers/platform/surface/aggregator/core.c create mode 100644 drivers/platform/surface/aggregator/ssh_msgb.h create mode 100644 drivers/platform/surface/aggregator/ssh_packet_layer.c create mode 100644 drivers/platform/surface/aggregator/ssh_packet_layer.h create mode 100644 drivers/platform/surface/aggregator/ssh_parser.c create mode 100644 drivers/platform/surface/aggregator/ssh_parser.h create mode 100644 drivers/platform/surface/aggregator/ssh_request_layer.c create mode 100644 drivers/platform/surface/aggregator/ssh_request_layer.h (limited to 'drivers/platform/surface') diff --git a/drivers/platform/surface/Kconfig b/drivers/platform/surface/Kconfig index 2c941cdac9ee..2916a47b130e 100644 --- a/drivers/platform/surface/Kconfig +++ b/drivers/platform/surface/Kconfig @@ -56,4 +56,6 @@ config SURFACE_PRO3_BUTTON help This driver handles the power/home/volume buttons on the Microsoft Surface Pro 3/4 tablet. +source "drivers/platform/surface/aggregator/Kconfig" + endif # SURFACE_PLATFORMS diff --git a/drivers/platform/surface/Makefile b/drivers/platform/surface/Makefile index cedfb027ded1..034134fe0264 100644 --- a/drivers/platform/surface/Makefile +++ b/drivers/platform/surface/Makefile @@ -7,5 +7,6 @@ obj-$(CONFIG_SURFACE3_WMI) += surface3-wmi.o obj-$(CONFIG_SURFACE_3_BUTTON) += surface3_button.o obj-$(CONFIG_SURFACE_3_POWER_OPREGION) += surface3_power.o +obj-$(CONFIG_SURFACE_AGGREGATOR) += aggregator/ obj-$(CONFIG_SURFACE_GPE) += surface_gpe.o obj-$(CONFIG_SURFACE_PRO3_BUTTON) += surfacepro3_button.o diff --git a/drivers/platform/surface/aggregator/Kconfig b/drivers/platform/surface/aggregator/Kconfig new file mode 100644 index 000000000000..e9f4ad96e40a --- /dev/null +++ b/drivers/platform/surface/aggregator/Kconfig @@ -0,0 +1,42 @@ +# SPDX-License-Identifier: GPL-2.0+ +# Copyright (C) 2019-2020 Maximilian Luz + +menuconfig SURFACE_AGGREGATOR + tristate "Microsoft Surface System Aggregator Module Subsystem and Drivers" + depends on SERIAL_DEV_BUS + select CRC_CCITT + help + The Surface System Aggregator Module (Surface SAM or SSAM) is an + embedded controller (EC) found on 5th- and later-generation Microsoft + Surface devices (i.e. Surface Pro 5, Surface Book 2, Surface Laptop, + and newer, with exception of Surface Go series devices). + + Depending on the device in question, this EC provides varying + functionality, including: + - EC access from ACPI via Surface ACPI Notify (5th- and 6th-generation) + - battery status information (all devices) + - thermal sensor access (all devices) + - performance mode / cooling mode control (all devices) + - clipboard detachment system control (Surface Book 2 and 3) + - HID / keyboard input (Surface Laptops, Surface Book 3) + + This option controls whether the Surface SAM subsystem core will be + built. This includes a driver for the Surface Serial Hub (SSH), which + is the device responsible for the communication with the EC, and a + basic kernel interface exposing the EC functionality to other client + drivers, i.e. allowing them to make requests to the EC and receive + events from it. Selecting this option alone will not provide any + client drivers and therefore no functionality beyond the in-kernel + interface. Said functionality is the responsibility of the respective + client drivers. + + Note: While 4th-generation Surface devices also make use of a SAM EC, + due to a difference in the communication interface of the controller, + only 5th and later generations are currently supported. Specifically, + devices using SAM-over-SSH are supported, whereas devices using + SAM-over-HID, which is used on the 4th generation, are currently not + supported. + + Choose m if you want to build the SAM subsystem core and SSH driver as + module, y if you want to build it into the kernel and n if you don't + want it at all. diff --git a/drivers/platform/surface/aggregator/Makefile b/drivers/platform/surface/aggregator/Makefile new file mode 100644 index 000000000000..faad18d4a7f2 --- /dev/null +++ b/drivers/platform/surface/aggregator/Makefile @@ -0,0 +1,10 @@ +# SPDX-License-Identifier: GPL-2.0+ +# Copyright (C) 2019-2020 Maximilian Luz + +obj-$(CONFIG_SURFACE_AGGREGATOR) += surface_aggregator.o + +surface_aggregator-objs := core.o +surface_aggregator-objs += ssh_parser.o +surface_aggregator-objs += ssh_packet_layer.o +surface_aggregator-objs += ssh_request_layer.o +surface_aggregator-objs += controller.o diff --git a/drivers/platform/surface/aggregator/controller.c b/drivers/platform/surface/aggregator/controller.c new file mode 100644 index 000000000000..488318cf2098 --- /dev/null +++ b/drivers/platform/surface/aggregator/controller.c @@ -0,0 +1,2504 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Main SSAM/SSH controller structure and functionality. + * + * Copyright (C) 2019-2020 Maximilian Luz + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include + +#include "controller.h" +#include "ssh_msgb.h" +#include "ssh_request_layer.h" + + +/* -- Safe counters. -------------------------------------------------------- */ + +/** + * ssh_seq_reset() - Reset/initialize sequence ID counter. + * @c: The counter to reset. + */ +static void ssh_seq_reset(struct ssh_seq_counter *c) +{ + WRITE_ONCE(c->value, 0); +} + +/** + * ssh_seq_next() - Get next sequence ID. + * @c: The counter providing the sequence IDs. + * + * Return: Returns the next sequence ID of the counter. + */ +static u8 ssh_seq_next(struct ssh_seq_counter *c) +{ + u8 old = READ_ONCE(c->value); + u8 new = old + 1; + u8 ret; + + while (unlikely((ret = cmpxchg(&c->value, old, new)) != old)) { + old = ret; + new = old + 1; + } + + return old; +} + +/** + * ssh_rqid_reset() - Reset/initialize request ID counter. + * @c: The counter to reset. + */ +static void ssh_rqid_reset(struct ssh_rqid_counter *c) +{ + WRITE_ONCE(c->value, 0); +} + +/** + * ssh_rqid_next() - Get next request ID. + * @c: The counter providing the request IDs. + * + * Return: Returns the next request ID of the counter, skipping any reserved + * request IDs. + */ +static u16 ssh_rqid_next(struct ssh_rqid_counter *c) +{ + u16 old = READ_ONCE(c->value); + u16 new = ssh_rqid_next_valid(old); + u16 ret; + + while (unlikely((ret = cmpxchg(&c->value, old, new)) != old)) { + old = ret; + new = ssh_rqid_next_valid(old); + } + + return old; +} + + +/* -- Event notifier/callbacks. --------------------------------------------- */ +/* + * The notifier system is based on linux/notifier.h, specifically the SRCU + * implementation. The difference to that is, that some bits of the notifier + * call return value can be tracked across multiple calls. This is done so + * that handling of events can be tracked and a warning can be issued in case + * an event goes unhandled. The idea of that warning is that it should help + * discover and identify new/currently unimplemented features. + */ + +/** + * ssam_event_matches_notifier() - Test if an event matches a notifier. + * @n: The event notifier to test against. + * @event: The event to test. + * + * Return: Returns %true if the given event matches the given notifier + * according to the rules set in the notifier's event mask, %false otherwise. + */ +static bool ssam_event_matches_notifier(const struct ssam_event_notifier *n, + const struct ssam_event *event) +{ + bool match = n->event.id.target_category == event->target_category; + + if (n->event.mask & SSAM_EVENT_MASK_TARGET) + match &= n->event.reg.target_id == event->target_id; + + if (n->event.mask & SSAM_EVENT_MASK_INSTANCE) + match &= n->event.id.instance == event->instance_id; + + return match; +} + +/** + * ssam_nfblk_call_chain() - Call event notifier callbacks of the given chain. + * @nh: The notifier head for which the notifier callbacks should be called. + * @event: The event data provided to the callbacks. + * + * Call all registered notifier callbacks in order of their priority until + * either no notifier is left or a notifier returns a value with the + * %SSAM_NOTIF_STOP bit set. Note that this bit is automatically set via + * ssam_notifier_from_errno() on any non-zero error value. + * + * Return: Returns the notifier status value, which contains the notifier + * status bits (%SSAM_NOTIF_HANDLED and %SSAM_NOTIF_STOP) as well as a + * potential error value returned from the last executed notifier callback. + * Use ssam_notifier_to_errno() to convert this value to the original error + * value. + */ +static int ssam_nfblk_call_chain(struct ssam_nf_head *nh, struct ssam_event *event) +{ + struct ssam_event_notifier *nf; + int ret = 0, idx; + + idx = srcu_read_lock(&nh->srcu); + + list_for_each_entry_rcu(nf, &nh->head, base.node, + srcu_read_lock_held(&nh->srcu)) { + if (ssam_event_matches_notifier(nf, event)) { + ret = (ret & SSAM_NOTIF_STATE_MASK) | nf->base.fn(nf, event); + if (ret & SSAM_NOTIF_STOP) + break; + } + } + + srcu_read_unlock(&nh->srcu, idx); + return ret; +} + +/** + * ssam_nfblk_insert() - Insert a new notifier block into the given notifier + * list. + * @nh: The notifier head into which the block should be inserted. + * @nb: The notifier block to add. + * + * Note: This function must be synchronized by the caller with respect to other + * insert, find, and/or remove calls by holding ``struct ssam_nf.lock``. + * + * Return: Returns zero on success, %-EEXIST if the notifier block has already + * been registered. + */ +static int ssam_nfblk_insert(struct ssam_nf_head *nh, struct ssam_notifier_block *nb) +{ + struct ssam_notifier_block *p; + struct list_head *h; + + /* Runs under lock, no need for RCU variant. */ + list_for_each(h, &nh->head) { + p = list_entry(h, struct ssam_notifier_block, node); + + if (unlikely(p == nb)) { + WARN(1, "double register detected"); + return -EEXIST; + } + + if (nb->priority > p->priority) + break; + } + + list_add_tail_rcu(&nb->node, h); + return 0; +} + +/** + * ssam_nfblk_find() - Check if a notifier block is registered on the given + * notifier head. + * list. + * @nh: The notifier head on which to search. + * @nb: The notifier block to search for. + * + * Note: This function must be synchronized by the caller with respect to other + * insert, find, and/or remove calls by holding ``struct ssam_nf.lock``. + * + * Return: Returns true if the given notifier block is registered on the given + * notifier head, false otherwise. + */ +static bool ssam_nfblk_find(struct ssam_nf_head *nh, struct ssam_notifier_block *nb) +{ + struct ssam_notifier_block *p; + + /* Runs under lock, no need for RCU variant. */ + list_for_each_entry(p, &nh->head, node) { + if (p == nb) + return true; + } + + return false; +} + +/** + * ssam_nfblk_remove() - Remove a notifier block from its notifier list. + * @nb: The notifier block to be removed. + * + * Note: This function must be synchronized by the caller with respect to + * other insert, find, and/or remove calls by holding ``struct ssam_nf.lock``. + * Furthermore, the caller _must_ ensure SRCU synchronization by calling + * synchronize_srcu() with ``nh->srcu`` after leaving the critical section, to + * ensure that the removed notifier block is not in use any more. + */ +static void ssam_nfblk_remove(struct ssam_notifier_block *nb) +{ + list_del_rcu(&nb->node); +} + +/** + * ssam_nf_head_init() - Initialize the given notifier head. + * @nh: The notifier head to initialize. + */ +static int ssam_nf_head_init(struct ssam_nf_head *nh) +{ + int status; + + status = init_srcu_struct(&nh->srcu); + if (status) + return status; + + INIT_LIST_HEAD(&nh->head); + return 0; +} + +/** + * ssam_nf_head_destroy() - Deinitialize the given notifier head. + * @nh: The notifier head to deinitialize. + */ +static void ssam_nf_head_destroy(struct ssam_nf_head *nh) +{ + cleanup_srcu_struct(&nh->srcu); +} + + +/* -- Event/notification registry. ------------------------------------------ */ + +/** + * struct ssam_nf_refcount_key - Key used for event activation reference + * counting. + * @reg: The registry via which the event is enabled/disabled. + * @id: The ID uniquely describing the event. + */ +struct ssam_nf_refcount_key { + struct ssam_event_registry reg; + struct ssam_event_id id; +}; + +/** + * struct ssam_nf_refcount_entry - RB-tree entry for reference counting event + * activations. + * @node: The node of this entry in the rb-tree. + * @key: The key of the event. + * @refcount: The reference-count of the event. + * @flags: The flags used when enabling the event. + */ +struct ssam_nf_refcount_entry { + struct rb_node node; + struct ssam_nf_refcount_key key; + int refcount; + u8 flags; +}; + +/** + * ssam_nf_refcount_inc() - Increment reference-/activation-count of the given + * event. + * @nf: The notifier system reference. + * @reg: The registry used to enable/disable the event. + * @id: The event ID. + * + * Increments the reference-/activation-count associated with the specified + * event type/ID, allocating a new entry for this event ID if necessary. A + * newly allocated entry will have a refcount of one. + * + * Note: ``nf->lock`` must be held when calling this function. + * + * Return: Returns the refcount entry on success. Returns an error pointer + * with %-ENOSPC if there have already been %INT_MAX events of the specified + * ID and type registered, or %-ENOMEM if the entry could not be allocated. + */ +static struct ssam_nf_refcount_entry * +ssam_nf_refcount_inc(struct ssam_nf *nf, struct ssam_event_registry reg, + struct ssam_event_id id) +{ + struct ssam_nf_refcount_entry *entry; + struct ssam_nf_refcount_key key; + struct rb_node **link = &nf->refcount.rb_node; + struct rb_node *parent = NULL; + int cmp; + + lockdep_assert_held(&nf->lock); + + key.reg = reg; + key.id = id; + + while (*link) { + entry = rb_entry(*link, struct ssam_nf_refcount_entry, node); + parent = *link; + + cmp = memcmp(&key, &entry->key, sizeof(key)); + if (cmp < 0) { + link = &(*link)->rb_left; + } else if (cmp > 0) { + link = &(*link)->rb_right; + } else if (entry->refcount < INT_MAX) { + entry->refcount++; + return entry; + } else { + WARN_ON(1); + return ERR_PTR(-ENOSPC); + } + } + + entry = kzalloc(sizeof(*entry), GFP_KERNEL); + if (!entry) + return ERR_PTR(-ENOMEM); + + entry->key = key; + entry->refcount = 1; + + rb_link_node(&entry->node, parent, link); + rb_insert_color(&entry->node, &nf->refcount); + + return entry; +} + +/** + * ssam_nf_refcount_dec() - Decrement reference-/activation-count of the given + * event. + * @nf: The notifier system reference. + * @reg: The registry used to enable/disable the event. + * @id: The event ID. + * + * Decrements the reference-/activation-count of the specified event, + * returning its entry. If the returned entry has a refcount of zero, the + * caller is responsible for freeing it using kfree(). + * + * Note: ``nf->lock`` must be held when calling this function. + * + * Return: Returns the refcount entry on success or %NULL if the entry has not + * been found. + */ +static struct ssam_nf_refcount_entry * +ssam_nf_refcount_dec(struct ssam_nf *nf, struct ssam_event_registry reg, + struct ssam_event_id id) +{ + struct ssam_nf_refcount_entry *entry; + struct ssam_nf_refcount_key key; + struct rb_node *node = nf->refcount.rb_node; + int cmp; + + lockdep_assert_held(&nf->lock); + + key.reg = reg; + key.id = id; + + while (node) { + entry = rb_entry(node, struct ssam_nf_refcount_entry, node); + + cmp = memcmp(&key, &entry->key, sizeof(key)); + if (cmp < 0) { + node = node->rb_left; + } else if (cmp > 0) { + node = node->rb_right; + } else { + entry->refcount--; + if (entry->refcount == 0) + rb_erase(&entry->node, &nf->refcount); + + return entry; + } + } + + return NULL; +} + +/** + * ssam_nf_refcount_empty() - Test if the notification system has any + * enabled/active events. + * @nf: The notification system. + */ +static bool ssam_nf_refcount_empty(struct ssam_nf *nf) +{ + return RB_EMPTY_ROOT(&nf->refcount); +} + +/** + * ssam_nf_call() - Call notification callbacks for the provided event. + * @nf: The notifier system + * @dev: The associated device, only used for logging. + * @rqid: The request ID of the event. + * @event: The event provided to the callbacks. + * + * Execute registered callbacks in order of their priority until either no + * callback is left or a callback returns a value with the %SSAM_NOTIF_STOP + * bit set. Note that this bit is set automatically when converting non-zero + * error values via ssam_notifier_from_errno() to notifier values. + * + * Also note that any callback that could handle an event should return a value + * with bit %SSAM_NOTIF_HANDLED set, indicating that the event does not go + * unhandled/ignored. In case no registered callback could handle an event, + * this function will emit a warning. + * + * In case a callback failed, this function will emit an error message. + */ +static void ssam_nf_call(struct ssam_nf *nf, struct device *dev, u16 rqid, + struct ssam_event *event) +{ + struct ssam_nf_head *nf_head; + int status, nf_ret; + + if (!ssh_rqid_is_event(rqid)) { + dev_warn(dev, "event: unsupported rqid: %#06x\n", rqid); + return; + } + + nf_head = &nf->head[ssh_rqid_to_event(rqid)]; + nf_ret = ssam_nfblk_call_chain(nf_head, event); + status = ssam_notifier_to_errno(nf_ret); + + if (status < 0) { + dev_err(dev, + "event: error handling event: %d (tc: %#04x, tid: %#04x, cid: %#04x, iid: %#04x)\n", + status, event->target_category, event->target_id, + event->command_id, event->instance_id); + } else if (!(nf_ret & SSAM_NOTIF_HANDLED)) { + dev_warn(dev, + "event: unhandled event (rqid: %#04x, tc: %#04x, tid: %#04x, cid: %#04x, iid: %#04x)\n", + rqid, event->target_category, event->target_id, + event->command_id, event->instance_id); + } +} + +/** + * ssam_nf_init() - Initialize the notifier system. + * @nf: The notifier system to initialize. + */ +static int ssam_nf_init(struct ssam_nf *nf) +{ + int i, status; + + for (i = 0; i < SSH_NUM_EVENTS; i++) { + status = ssam_nf_head_init(&nf->head[i]); + if (status) + break; + } + + if (status) { + while (i--) + ssam_nf_head_destroy(&nf->head[i]); + + return status; + } + + mutex_init(&nf->lock); + return 0; +} + +/** + * ssam_nf_destroy() - Deinitialize the notifier system. + * @nf: The notifier system to deinitialize. + */ +static void ssam_nf_destroy(struct ssam_nf *nf) +{ + int i; + + for (i = 0; i < SSH_NUM_EVENTS; i++) + ssam_nf_head_destroy(&nf->head[i]); + + mutex_destroy(&nf->lock); +} + + +/* -- Event/async request completion system. -------------------------------- */ + +#define SSAM_CPLT_WQ_NAME "ssam_cpltq" + +/* + * SSAM_CPLT_WQ_BATCH - Maximum number of event item completions executed per + * work execution. Used to prevent livelocking of the workqueue. Value chosen + * via educated guess, may be adjusted. + */ +#define SSAM_CPLT_WQ_BATCH 10 + +/** + * ssam_event_item_alloc() - Allocate an event item with the given payload size. + * @len: The event payload length. + * @flags: The flags used for allocation. + * + * Allocate an event item with the given payload size. Sets the item + * operations and payload length values. The item free callback (``ops.free``) + * should not be overwritten after this call. + * + * Return: Returns the newly allocated event item. + */ +static struct ssam_event_item *ssam_event_item_alloc(size_t len, gfp_t flags) +{ + struct ssam_event_item *item; + + item = kzalloc(struct_size(item, event.data, len), flags); + if (!item) + return NULL; + + item->event.length = len; + return item; +} + +/** + * ssam_event_queue_push() - Push an event item to the event queue. + * @q: The event queue. + * @item: The item to add. + */ +static void ssam_event_queue_push(struct ssam_event_queue *q, + struct ssam_event_item *item) +{ + spin_lock(&q->lock); + list_add_tail(&item->node, &q->head); + spin_unlock(&q->lock); +} + +/** + * ssam_event_queue_pop() - Pop the next event item from the event queue. + * @q: The event queue. + * + * Returns and removes the next event item from the queue. Returns %NULL If + * there is no event item left. + */ +static struct ssam_event_item *ssam_event_queue_pop(struct ssam_event_queue *q) +{ + struct ssam_event_item *item; + + spin_lock(&q->lock); + item = list_first_entry_or_null(&q->head, struct ssam_event_item, node); + if (item) + list_del(&item->node); + spin_unlock(&q->lock); + + return item; +} + +/** + * ssam_event_queue_is_empty() - Check if the event queue is empty. + * @q: The event queue. + */ +static bool ssam_event_queue_is_empty(struct ssam_event_queue *q) +{ + bool empty; + + spin_lock(&q->lock); + empty = list_empty(&q->head); + spin_unlock(&q->lock); + + return empty; +} + +/** + * ssam_cplt_get_event_queue() - Get the event queue for the given parameters. + * @cplt: The completion system on which to look for the queue. + * @tid: The target ID of the queue. + * @rqid: The request ID representing the event ID for which to get the queue. + * + * Return: Returns the event queue corresponding to the event type described + * by the given parameters. If the request ID does not represent an event, + * this function returns %NULL. If the target ID is not supported, this + * function will fall back to the default target ID (``tid = 1``). + */ +static +struct ssam_event_queue *ssam_cplt_get_event_queue(struct ssam_cplt *cplt, + u8 tid, u16 rqid) +{ + u16 event = ssh_rqid_to_event(rqid); + u16 tidx = ssh_tid_to_index(tid); + + if (!ssh_rqid_is_event(rqid)) { + dev_err(cplt->dev, "event: unsupported request ID: %#06x\n", rqid); + return NULL; + } + + if (!ssh_tid_is_valid(tid)) { + dev_warn(cplt->dev, "event: unsupported target ID: %u\n", tid); + tidx = 0; + } + + return &cplt->event.target[tidx].queue[event]; +} + +/** + * ssam_cplt_submit() - Submit a work item to the completion system workqueue. + * @cplt: The completion system. + * @work: The work item to submit. + */ +static bool ssam_cplt_submit(struct ssam_cplt *cplt, struct work_struct *work) +{ + return queue_work(cplt->wq, work); +} + +/** + * ssam_cplt_submit_event() - Submit an event to the completion system. + * @cplt: The completion system. + * @item: The event item to submit. + * + * Submits the event to the completion system by queuing it on the event item + * queue and queuing the respective event queue work item on the completion + * workqueue, which will eventually complete the event. + * + * Return: Returns zero on success, %-EINVAL if there is no event queue that + * can handle the given event item. + */ +static int ssam_cplt_submit_event(struct ssam_cplt *cplt, + struct ssam_event_item *item) +{ + struct ssam_event_queue *evq; + + evq = ssam_cplt_get_event_queue(cplt, item->event.target_id, item->rqid); + if (!evq) + return -EINVAL; + + ssam_event_queue_push(evq, item); + ssam_cplt_submit(cplt, &evq->work); + return 0; +} + +/** + * ssam_cplt_flush() - Flush the completion system. + * @cplt: The completion system. + * + * Flush the completion system by waiting until all currently submitted work + * items have been completed. + * + * Note: This function does not guarantee that all events will have been + * handled once this call terminates. In case of a larger number of + * to-be-completed events, the event queue work function may re-schedule its + * work item, which this flush operation will ignore. + * + * This operation is only intended to, during normal operation prior to + * shutdown, try to complete most events and requests to get them out of the + * system while the system is still fully operational. It does not aim to + * provide any guarantee that all of them have been handled. + */ +static void ssam_cplt_flush(struct ssam_cplt *cplt) +{ + flush_workqueue(cplt->wq); +} + +static void ssam_event_queue_work_fn(struct work_struct *work) +{ + struct ssam_event_queue *queue; + struct ssam_event_item *item; + struct ssam_nf *nf; + struct device *dev; + unsigned int iterations = SSAM_CPLT_WQ_BATCH; + + queue = container_of(work, struct ssam_event_queue, work); + nf = &queue->cplt->event.notif; + dev = queue->cplt->dev; + + /* Limit number of processed events to avoid livelocking. */ + do { + item = ssam_event_queue_pop(queue); + if (!item) + return; + + ssam_nf_call(nf, dev, item->rqid, &item->event); + kfree(item); + } while (--iterations); + + if (!ssam_event_queue_is_empty(queue)) + ssam_cplt_submit(queue->cplt, &queue->work); +} + +/** + * ssam_event_queue_init() - Initialize an event queue. + * @cplt: The completion system on which the queue resides. + * @evq: The event queue to initialize. + */ +static void ssam_event_queue_init(struct ssam_cplt *cplt, + struct ssam_event_queue *evq) +{ + evq->cplt = cplt; + spin_lock_init(&evq->lock); + INIT_LIST_HEAD(&evq->head); + INIT_WORK(&evq->work, ssam_event_queue_work_fn); +} + +/** + * ssam_cplt_init() - Initialize completion system. + * @cplt: The completion system to initialize. + * @dev: The device used for logging. + */ +static int ssam_cplt_init(struct ssam_cplt *cplt, struct device *dev) +{ + struct ssam_event_target *target; + int status, c, i; + + cplt->dev = dev; + + cplt->wq = create_workqueue(SSAM_CPLT_WQ_NAME); + if (!cplt->wq) + return -ENOMEM; + + for (c = 0; c < ARRAY_SIZE(cplt->event.target); c++) { + target = &cplt->event.target[c]; + + for (i = 0; i < ARRAY_SIZE(target->queue); i++) + ssam_event_queue_init(cplt, &target->queue[i]); + } + + status = ssam_nf_init(&cplt->event.notif); + if (status) + destroy_workqueue(cplt->wq); + + return status; +} + +/** + * ssam_cplt_destroy() - Deinitialize the completion system. + * @cplt: The completion system to deinitialize. + * + * Deinitialize the given completion system and ensure that all pending, i.e. + * yet-to-be-completed, event items and requests have been handled. + */ +static void ssam_cplt_destroy(struct ssam_cplt *cplt) +{ + /* + * Note: destroy_workqueue ensures that all currently queued work will + * be fully completed and the workqueue drained. This means that this + * call will inherently also free any queued ssam_event_items, thus we + * don't have to take care of that here explicitly. + */ + destroy_workqueue(cplt->wq); + ssam_nf_destroy(&cplt->event.notif); +} + + +/* -- Main SSAM device structures. ------------------------------------------ */ + +/** + * ssam_controller_device() - Get the &struct device associated with this + * controller. + * @c: The controller for which to get the device. + * + * Return: Returns the &struct device associated with this controller, + * providing its lower-level transport. + */ +struct device *ssam_controller_device(struct ssam_controller *c) +{ + return ssh_rtl_get_device(&c->rtl); +} +EXPORT_SYMBOL_GPL(ssam_controller_device); + +static void __ssam_controller_release(struct kref *kref) +{ + struct ssam_controller *ctrl = to_ssam_controller(kref, kref); + + /* + * The lock-call here is to satisfy lockdep. At this point we really + * expect this to be the last remaining reference to the controller. + * Anything else is a bug. + */ + ssam_controller_lock(ctrl); + ssam_controller_destroy(ctrl); + ssam_controller_unlock(ctrl); + + kfree(ctrl); +} + +/** + * ssam_controller_get() - Increment reference count of controller. + * @c: The controller. + * + * Return: Returns the controller provided as input. + */ +struct ssam_controller *ssam_controller_get(struct ssam_controller *c) +{ + if (c) + kref_get(&c->kref); + return c; +} +EXPORT_SYMBOL_GPL(ssam_controller_get); + +/** + * ssam_controller_put() - Decrement reference count of controller. + * @c: The controller. + */ +void ssam_controller_put(struct ssam_controller *c) +{ + if (c) + kref_put(&c->kref, __ssam_controller_release); +} +EXPORT_SYMBOL_GPL(ssam_controller_put); + +/** + * ssam_controller_statelock() - Lock the controller against state transitions. + * @c: The controller to lock. + * + * Lock the controller against state transitions. Holding this lock guarantees + * that the controller will not transition between states, i.e. if the + * controller is in state "started", when this lock has been acquired, it will + * remain in this state at least until the lock has been released. + * + * Multiple clients may concurrently hold this lock. In other words: The + * ``statelock`` functions represent the read-lock part of a r/w-semaphore. + * Actions causing state transitions of the controller must be executed while + * holding the write-part of this r/w-semaphore (see ssam_controller_lock() + * and ssam_controller_unlock() for that). + * + * See ssam_controller_stateunlock() for the corresponding unlock function. + */ +void ssam_controller_statelock(struct ssam_controller *c) +{ + down_read(&c->lock); +} +EXPORT_SYMBOL_GPL(ssam_controller_statelock); + +/** + * ssam_controller_stateunlock() - Unlock controller state transitions. + * @c: The controller to unlock. + * + * See ssam_controller_statelock() for the corresponding lock function. + */ +void ssam_controller_stateunlock(struct ssam_controller *c) +{ + up_read(&c->lock); +} +EXPORT_SYMBOL_GPL(ssam_controller_stateunlock); + +/** + * ssam_controller_lock() - Acquire the main controller lock. + * @c: The controller to lock. + * + * This lock must be held for any state transitions, including transition to + * suspend/resumed states and during shutdown. See ssam_controller_statelock() + * for more details on controller locking. + * + * See ssam_controller_unlock() for the corresponding unlock function. + */ +void ssam_controller_lock(struct ssam_controller *c) +{ + down_write(&c->lock); +} + +/* + * ssam_controller_unlock() - Release the main controller lock. + * @c: The controller to unlock. + * + * See ssam_controller_lock() for the corresponding lock function. + */ +void ssam_controller_unlock(struct ssam_controller *c) +{ + up_write(&c->lock); +} + +static void ssam_handle_event(struct ssh_rtl *rtl, + const struct ssh_command *cmd, + const struct ssam_span *data) +{ + struct ssam_controller *ctrl = to_ssam_controller(rtl, rtl); + struct ssam_event_item *item; + + item = ssam_event_item_alloc(data->len, GFP_KERNEL); + if (!item) + return; + + item->rqid = get_unaligned_le16(&cmd->rqid); + item->event.target_category = cmd->tc; + item->event.target_id = cmd->tid_in; + item->event.command_id = cmd->cid; + item->event.instance_id = cmd->iid; + memcpy(&item->event.data[0], data->ptr, data->len); + + if (WARN_ON(ssam_cplt_submit_event(&ctrl->cplt, item))) + kfree(item); +} + +static const struct ssh_rtl_ops ssam_rtl_ops = { + .handle_event = ssam_handle_event, +}; + +static bool ssam_notifier_is_empty(struct ssam_controller *ctrl); +static void ssam_notifier_unregister_all(struct ssam_controller *ctrl); + +#define SSAM_SSH_DSM_REVISION 0 + +/* d5e383e1-d892-4a76-89fc-f6aaae7ed5b5 */ +static const guid_t SSAM_SSH_DSM_GUID = + GUID_INIT(0xd5e383e1, 0xd892, 0x4a76, + 0x89, 0xfc, 0xf6, 0xaa, 0xae, 0x7e, 0xd5, 0xb5); + +enum ssh_dsm_fn { + SSH_DSM_FN_SSH_POWER_PROFILE = 0x05, + SSH_DSM_FN_SCREEN_ON_SLEEP_IDLE_TIMEOUT = 0x06, + SSH_DSM_FN_SCREEN_OFF_SLEEP_IDLE_TIMEOUT = 0x07, + SSH_DSM_FN_D3_CLOSES_HANDLE = 0x08, + SSH_DSM_FN_SSH_BUFFER_SIZE = 0x09, +}; + +static int ssam_dsm_get_functions(acpi_handle handle, u64 *funcs) +{ + union acpi_object *obj; + u64 mask = 0; + int i; + + *funcs = 0; + + /* + * The _DSM function is only present on newer models. It is not + * present on 5th and 6th generation devices (i.e. up to and including + * Surface Pro 6, Surface Laptop 2, Surface Book 2). + * + * If the _DSM is not present, indicate that no function is supported. + * This will result in default values being set. + */ + if (!acpi_has_method(handle, "_DSM")) + return 0; + + obj = acpi_evaluate_dsm_typed(handle, &SSAM_SSH_DSM_GUID, + SSAM_SSH_DSM_REVISION, 0, NULL, + ACPI_TYPE_BUFFER); + if (!obj) + return -EIO; + + for (i = 0; i < obj->buffer.length && i < 8; i++) + mask |= (((u64)obj->buffer.pointer[i]) << (i * 8)); + + if (mask & BIT(0)) + *funcs = mask; + + ACPI_FREE(obj); + return 0; +} + +static int ssam_dsm_load_u32(acpi_handle handle, u64 funcs, u64 func, u32 *ret) +{ + union acpi_object *obj; + u64 val; + + if (!(funcs & BIT(func))) + return 0; /* Not supported, leave *ret at its default value */ + + obj = acpi_evaluate_dsm_typed(handle, &SSAM_SSH_DSM_GUID, + SSAM_SSH_DSM_REVISION, func, NULL, + ACPI_TYPE_INTEGER); + if (!obj) + return -EIO; + + val = obj->integer.value; + ACPI_FREE(obj); + + if (val > U32_MAX) + return -ERANGE; + + *ret = val; + return 0; +} + +/** + * ssam_controller_caps_load_from_acpi() - Load controller capabilities from + * ACPI _DSM. + * @handle: The handle of the ACPI controller/SSH device. + * @caps: Where to store the capabilities in. + * + * Initializes the given controller capabilities with default values, then + * checks and, if the respective _DSM functions are available, loads the + * actual capabilities from the _DSM. + * + * Return: Returns zero on success, a negative error code on failure. + */ +static +int ssam_controller_caps_load_from_acpi(acpi_handle handle, + struct ssam_controller_caps *caps) +{ + u32 d3_closes_handle = false; + u64 funcs; + int status; + + /* Set defaults. */ + caps->ssh_power_profile = U32_MAX; + caps->screen_on_sleep_idle_timeout = U32_MAX; + caps->screen_off_sleep_idle_timeout = U32_MAX; + caps->d3_closes_handle = false; + caps->ssh_buffer_size = U32_MAX; + + /* Pre-load supported DSM functions. */ + status = ssam_dsm_get_functions(handle, &funcs); + if (status) + return status; + + /* Load actual values from ACPI, if present. */ + status = ssam_dsm_load_u32(handle, funcs, SSH_DSM_FN_SSH_POWER_PROFILE, + &caps->ssh_power_profile); + if (status) + return status; + + status = ssam_dsm_load_u32(handle, funcs, + SSH_DSM_FN_SCREEN_ON_SLEEP_IDLE_TIMEOUT, + &caps->screen_on_sleep_idle_timeout); + if (status) + return status; + + status = ssam_dsm_load_u32(handle, funcs, + SSH_DSM_FN_SCREEN_OFF_SLEEP_IDLE_TIMEOUT, + &caps->screen_off_sleep_idle_timeout); + if (status) + return status; + + status = ssam_dsm_load_u32(handle, funcs, SSH_DSM_FN_D3_CLOSES_HANDLE, + &d3_closes_handle); + if (status) + return status; + + caps->d3_closes_handle = !!d3_closes_handle; + + status = ssam_dsm_load_u32(handle, funcs, SSH_DSM_FN_SSH_BUFFER_SIZE, + &caps->ssh_buffer_size); + if (status) + return status; + + return 0; +} + +/** + * ssam_controller_init() - Initialize SSAM controller. + * @ctrl: The controller to initialize. + * @serdev: The serial device representing the underlying data transport. + * + * Initializes the given controller. Does neither start receiver nor + * transmitter threads. After this call, the controller has to be hooked up to + * the serdev core separately via &struct serdev_device_ops, relaying calls to + * ssam_controller_receive_buf() and ssam_controller_write_wakeup(). Once the + * controller has been hooked up, transmitter and receiver threads may be + * started via ssam_controller_start(). These setup steps need to be completed + * before controller can be used for requests. + */ +int ssam_controller_init(struct ssam_controller *ctrl, + struct serdev_device *serdev) +{ + acpi_handle handle = ACPI_HANDLE(&serdev->dev); + int status; + + init_rwsem(&ctrl->lock); + kref_init(&ctrl->kref); + + status = ssam_controller_caps_load_from_acpi(handle, &ctrl->caps); + if (status) + return status; + + dev_dbg(&serdev->dev, + "device capabilities:\n" + " ssh_power_profile: %u\n" + " ssh_buffer_size: %u\n" + " screen_on_sleep_idle_timeout: %u\n" + " screen_off_sleep_idle_timeout: %u\n" + " d3_closes_handle: %u\n", + ctrl->caps.ssh_power_profile, + ctrl->caps.ssh_buffer_size, + ctrl->caps.screen_on_sleep_idle_timeout, + ctrl->caps.screen_off_sleep_idle_timeout, + ctrl->caps.d3_closes_handle); + + ssh_seq_reset(&ctrl->counter.seq); + ssh_rqid_reset(&ctrl->counter.rqid); + + /* Initialize event/request completion system. */ + status = ssam_cplt_init(&ctrl->cplt, &serdev->dev); + if (status) + return status; + + /* Initialize request and packet transport layers. */ + status = ssh_rtl_init(&ctrl->rtl, serdev, &ssam_rtl_ops); + if (status) { + ssam_cplt_destroy(&ctrl->cplt); + return status; + } + + /* + * Set state via write_once even though we expect to be in an + * exclusive context, due to smoke-testing in + * ssam_request_sync_submit(). + */ + WRITE_ONCE(ctrl->state, SSAM_CONTROLLER_INITIALIZED); + return 0; +} + +/** + * ssam_controller_start() - Start the receiver and transmitter threads of the + * controller. + * @ctrl: The controller. + * + * Note: When this function is called, the controller should be properly + * hooked up to the serdev core via &struct serdev_device_ops. Please refer + * to ssam_controller_init() for more details on controller initialization. + * + * This function must be called with the main controller lock held (i.e. by + * calling ssam_controller_lock()). + */ +int ssam_controller_start(struct ssam_controller *ctrl) +{ + int status; + + lockdep_assert_held_write(&ctrl->lock); + + if (ctrl->state != SSAM_CONTROLLER_INITIALIZED) + return -EINVAL; + + status = ssh_rtl_start(&ctrl->rtl); + if (status) + return status; + + /* + * Set state via write_once even though we expect to be locked/in an + * exclusive context, due to smoke-testing in + * ssam_request_sync_submit(). + */ + WRITE_ONCE(ctrl->state, SSAM_CONTROLLER_STARTED); + return 0; +} + +/* + * SSAM_CTRL_SHUTDOWN_FLUSH_TIMEOUT - Timeout for flushing requests during + * shutdown. + * + * Chosen to be larger than one full request timeout, including packets timing + * out. This value should give ample time to complete any outstanding requests + * during normal operation and account for the odd package timeout. + */ +#define SSAM_CTRL_SHUTDOWN_FLUSH_TIMEOUT msecs_to_jiffies(5000) + +/** + * ssam_controller_shutdown() - Shut down the controller. + * @ctrl: The controller. + * + * Shuts down the controller by flushing all pending requests and stopping the + * transmitter and receiver threads. All requests submitted after this call + * will fail with %-ESHUTDOWN. While it is discouraged to do so, this function + * is safe to use in parallel with ongoing request submission. + * + * In the course of this shutdown procedure, all currently registered + * notifiers will be unregistered. It is, however, strongly recommended to not + * rely on this behavior, and instead the party registering the notifier + * should unregister it before the controller gets shut down, e.g. via the + * SSAM bus which guarantees client devices to be removed before a shutdown. + * + * Note that events may still be pending after this call, but, due to the + * notifiers being unregistered, these events will be dropped when the + * controller is subsequently destroyed via ssam_controller_destroy(). + * + * This function must be called with the main controller lock held (i.e. by + * calling ssam_controller_lock()). + */ +void ssam_controller_shutdown(struct ssam_controller *ctrl) +{ + enum ssam_controller_state s = ctrl->state; + int status; + + lockdep_assert_held_write(&ctrl->lock); + + if (s == SSAM_CONTROLLER_UNINITIALIZED || s == SSAM_CONTROLLER_STOPPED) + return; + + /* + * Try to flush pending events and requests while everything still + * works. Note: There may still be packets and/or requests in the + * system after this call (e.g. via control packets submitted by the + * packet transport layer or flush timeout / failure, ...). Those will + * be handled with the ssh_rtl_shutdown() call below. + */ + status = ssh_rtl_flush(&ctrl->rtl, SSAM_CTRL_SHUTDOWN_FLUSH_TIMEOUT); + if (status) { + ssam_err(ctrl, "failed to flush request transport layer: %d\n", + status); + } + + /* Try to flush all currently completing requests and events. */ + ssam_cplt_flush(&ctrl->cplt); + + /* + * We expect all notifiers to have been removed by the respective client + * driver that set them up at this point. If this warning occurs, some + * client driver has not done that... + */ + WARN_ON(!ssam_notifier_is_empty(ctrl)); + + /* + * Nevertheless, we should still take care of drivers that don't behave + * well. Thus disable all enabled events, unregister all notifiers. + */ + ssam_notifier_unregister_all(ctrl); + + /* + * Cancel remaining requests. Ensure no new ones can be queued and stop + * threads. + */ + ssh_rtl_shutdown(&ctrl->rtl); + + /* + * Set state via write_once even though we expect to be locked/in an + * exclusive context, due to smoke-testing in + * ssam_request_sync_submit(). + */ + WRITE_ONCE(ctrl->state, SSAM_CONTROLLER_STOPPED); + ctrl->rtl.ptl.serdev = NULL; +} + +/** + * ssam_controller_destroy() - Destroy the controller and free its resources. + * @ctrl: The controller. + * + * Ensures that all resources associated with the controller get freed. This + * function should only be called after the controller has been stopped via + * ssam_controller_shutdown(). In general, this function should not be called + * directly. The only valid place to call this function directly is during + * initialization, before the controller has been fully initialized and passed + * to other processes. This function is called automatically when the + * reference count of the controller reaches zero. + * + * This function must be called with the main controller lock held (i.e. by + * calling ssam_controller_lock()). + */ +void ssam_controller_destroy(struct ssam_controller *ctrl) +{ + lockdep_assert_held_write(&ctrl->lock); + + if (ctrl->state == SSAM_CONTROLLER_UNINITIALIZED) + return; + + WARN_ON(ctrl->state != SSAM_CONTROLLER_STOPPED); + + /* + * Note: New events could still have been received after the previous + * flush in ssam_controller_shutdown, before the request transport layer + * has been shut down. At this point, after the shutdown, we can be sure + * that no new events will be queued. The call to ssam_cplt_destroy will + * ensure that those remaining are being completed and freed. + */ + + /* Actually free resources. */ + ssam_cplt_destroy(&ctrl->cplt); + ssh_rtl_destroy(&ctrl->rtl); + + /* + * Set state via write_once even though we expect to be locked/in an + * exclusive context, due to smoke-testing in + * ssam_request_sync_submit(). + */ + WRITE_ONCE(ctrl->state, SSAM_CONTROLLER_UNINITIALIZED); +} + +/** + * ssam_controller_suspend() - Suspend the controller. + * @ctrl: The controller to suspend. + * + * Marks the controller as suspended. Note that display-off and D0-exit + * notifications have to be sent manually before transitioning the controller + * into the suspended state via this function. + * + * See ssam_controller_resume() for the corresponding resume function. + * + * Return: Returns %-EINVAL if the controller is currently not in the + * "started" state. + */ +int ssam_controller_suspend(struct ssam_controller *ctrl) +{ + ssam_controller_lock(ctrl); + + if (ctrl->state != SSAM_CONTROLLER_STARTED) { + ssam_controller_unlock(ctrl); + return -EINVAL; + } + + ssam_dbg(ctrl, "pm: suspending controller\n"); + + /* + * Set state via write_once even though we're locked, due to + * smoke-testing in ssam_request_sync_submit(). + */ + WRITE_ONCE(ctrl->state, SSAM_CONTROLLER_SUSPENDED); + + ssam_controller_unlock(ctrl); + return 0; +} + +/** + * ssam_controller_resume() - Resume the controller from suspend. + * @ctrl: The controller to resume. + * + * Resume the controller from the suspended state it was put into via + * ssam_controller_suspend(). This function does not issue display-on and + * D0-entry notifications. If required, those have to be sent manually after + * this call. + * + * Return: Returns %-EINVAL if the controller is currently not suspended. + */ +int ssam_controller_resume(struct ssam_controller *ctrl) +{ + ssam_controller_lock(ctrl); + + if (ctrl->state != SSAM_CONTROLLER_SUSPENDED) { + ssam_controller_unlock(ctrl); + return -EINVAL; + } + + ssam_dbg(ctrl, "pm: resuming controller\n"); + + /* + * Set state via write_once even though we're locked, due to + * smoke-testing in ssam_request_sync_submit(). + */ + WRITE_ONCE(ctrl->state, SSAM_CONTROLLER_STARTED); + + ssam_controller_unlock(ctrl); + return 0; +} + + +/* -- Top-level request interface ------------------------------------------- */ + +/** + * ssam_request_write_data() - Construct and write SAM request message to + * buffer. + * @buf: The buffer to write the data to. + * @ctrl: The controller via which the request will be sent. + * @spec: The request data and specification. + * + * Constructs a SAM/SSH request message and writes it to the provided buffer. + * The request and transport counters, specifically RQID and SEQ, will be set + * in this call. These counters are obtained from the controller. It is thus + * only valid to send the resulting message via the controller specified here. + * + * For calculation of the required buffer size, refer to the + * SSH_COMMAND_MESSAGE_LENGTH() macro. + * + * Return: Returns the number of bytes used in the buffer on success. Returns + * %-EINVAL if the payload length provided in the request specification is too + * large (larger than %SSH_COMMAND_MAX_PAYLOAD_SIZE) or if the provided buffer + * is too small. + */ +ssize_t ssam_request_write_data(struct ssam_span *buf, + struct ssam_controller *ctrl, + const struct ssam_request *spec) +{ + struct msgbuf msgb; + u16 rqid; + u8 seq; + + if (spec->length > SSH_COMMAND_MAX_PAYLOAD_SIZE) + return -EINVAL; + + if (SSH_COMMAND_MESSAGE_LENGTH(spec->length) > buf->len) + return -EINVAL; + + msgb_init(&msgb, buf->ptr, buf->len); + seq = ssh_seq_next(&ctrl->counter.seq); + rqid = ssh_rqid_next(&ctrl->counter.rqid); + msgb_push_cmd(&msgb, seq, rqid, spec); + + return msgb_bytes_used(&msgb); +} +EXPORT_SYMBOL_GPL(ssam_request_write_data); + +static void ssam_request_sync_complete(struct ssh_request *rqst, + const struct ssh_command *cmd, + const struct ssam_span *data, int status) +{ + struct ssh_rtl *rtl = ssh_request_rtl(rqst); + struct ssam_request_sync *r; + + r = container_of(rqst, struct ssam_request_sync, base); + r->status = status; + + if (r->resp) + r->resp->length = 0; + + if (status) { + rtl_dbg_cond(rtl, "rsp: request failed: %d\n", status); + return; + } + + if (!data) /* Handle requests without a response. */ + return; + + if (!r->resp || !r->resp->pointer) { + if (data->len) + rtl_warn(rtl, "rsp: no response buffer provided, dropping data\n"); + return; + } + + if (data->len > r->resp->capacity) { + rtl_err(rtl, + "rsp: response buffer too small, capacity: %zu bytes, got: %zu bytes\n", + r->resp->capacity, data->len); + r->status = -ENOSPC; + return; + } + + r->resp->length = data->len; + memcpy(r->resp->pointer, data->ptr, data->len); +} + +static void ssam_request_sync_release(struct ssh_request *rqst) +{ + complete_all(&container_of(rqst, struct ssam_request_sync, base)->comp); +} + +static const struct ssh_request_ops ssam_request_sync_ops = { + .release = ssam_request_sync_release, + .complete = ssam_request_sync_complete, +}; + +/** + * ssam_request_sync_alloc() - Allocate a synchronous request. + * @payload_len: The length of the request payload. + * @flags: Flags used for allocation. + * @rqst: Where to store the pointer to the allocated request. + * @buffer: Where to store the buffer descriptor for the message buffer of + * the request. + * + * Allocates a synchronous request with corresponding message buffer. The + * request still needs to be initialized ssam_request_sync_init() before + * it can be submitted, and the message buffer data must still be set to the + * returned buffer via ssam_request_sync_set_data() after it has been filled, + * if need be with adjusted message length. + * + * After use, the request and its corresponding message buffer should be freed + * via ssam_request_sync_free(). The buffer must not be freed separately. + * + * Return: Returns zero on success, %-ENOMEM if the request could not be + * allocated. + */ +int ssam_request_sync_alloc(size_t payload_len, gfp_t flags, + struct ssam_request_sync **rqst, + struct ssam_span *buffer) +{ + size_t msglen = SSH_COMMAND_MESSAGE_LENGTH(payload_len); + + *rqst = kzalloc(sizeof(**rqst) + msglen, flags); + if (!*rqst) + return -ENOMEM; + + buffer->ptr = (u8 *)(*rqst + 1); + buffer->len = msglen; + + return 0; +} +EXPORT_SYMBOL_GPL(ssam_request_sync_alloc); + +/** + * ssam_request_sync_free() - Free a synchronous request. + * @rqst: The request to be freed. + * + * Free a synchronous request and its corresponding buffer allocated with + * ssam_request_sync_alloc(). Do not use for requests allocated on the stack + * or via any other function. + * + * Warning: The caller must ensure that the request is not in use any more. + * I.e. the caller must ensure that it has the only reference to the request + * and the request is not currently pending. This means that the caller has + * either never submitted the request, request submission has failed, or the + * caller has waited until the submitted request has been completed via + * ssam_request_sync_wait(). + */ +void ssam_request_sync_free(struct ssam_request_sync *rqst) +{ + kfree(rqst); +} +EXPORT_SYMBOL_GPL(ssam_request_sync_free); + +/** + * ssam_request_sync_init() - Initialize a synchronous request struct. + * @rqst: The request to initialize. + * @flags: The request flags. + * + * Initializes the given request struct. Does not initialize the request + * message data. This has to be done explicitly after this call via + * ssam_request_sync_set_data() and the actual message data has to be written + * via ssam_request_write_data(). + * + * Return: Returns zero on success or %-EINVAL if the given flags are invalid. + */ +int ssam_request_sync_init(struct ssam_request_sync *rqst, + enum ssam_request_flags flags) +{ + int status; + + status = ssh_request_init(&rqst->base, flags, &ssam_request_sync_ops); + if (status) + return status; + + init_completion(&rqst->comp); + rqst->resp = NULL; + rqst->status = 0; + + return 0; +} +EXPORT_SYMBOL_GPL(ssam_request_sync_init); + +/** + * ssam_request_sync_submit() - Submit a synchronous request. + * @ctrl: The controller with which to submit the request. + * @rqst: The request to submit. + * + * Submit a synchronous request. The request has to be initialized and + * properly set up, including response buffer (may be %NULL if no response is + * expected) and command message data. This function does not wait for the + * request to be completed. + * + * If this function succeeds, ssam_request_sync_wait() must be used to ensure + * that the request has been completed before the response data can be + * accessed and/or the request can be freed. On failure, the request may + * immediately be freed. + * + * This function may only be used if the controller is active, i.e. has been + * initialized and not suspended. + */ +int ssam_request_sync_submit(struct ssam_controller *ctrl, + struct ssam_request_sync *rqst) +{ + int status; + + /* + * This is only a superficial check. In general, the caller needs to + * ensure that the controller is initialized and is not (and does not + * get) suspended during use, i.e. until the request has been completed + * (if _absolutely_ necessary, by use of ssam_controller_statelock/ + * ssam_controller_stateunlock, but something like ssam_client_link + * should be preferred as this needs to last until the request has been + * completed). + * + * Note that it is actually safe to use this function while the + * controller is in the process of being shut down (as ssh_rtl_submit + * is safe with regards to this), but it is generally discouraged to do + * so. + */ + if (WARN_ON(READ_ONCE(ctrl->state) != SSAM_CONTROLLER_STARTED)) { + ssh_request_put(&rqst->base); + return -ENODEV; + } + + status = ssh_rtl_submit(&ctrl->rtl, &rqst->base); + ssh_request_put(&rqst->base); + + return status; +} +EXPORT_SYMBOL_GPL(ssam_request_sync_submit); + +/** + * ssam_request_sync() - Execute a synchronous request. + * @ctrl: The controller via which the request will be submitted. + * @spec: The request specification and payload. + * @rsp: The response buffer. + * + * Allocates a synchronous request with its message data buffer on the heap + * via ssam_request_sync_alloc(), fully initializes it via the provided + * request specification, submits it, and finally waits for its completion + * before freeing it and returning its status. + * + * Return: Returns the status of the request or any failure during setup. + */ +int ssam_request_sync(struct ssam_controller *ctrl, + const struct ssam_request *spec, + struct ssam_response *rsp) +{ + struct ssam_request_sync *rqst; + struct ssam_span buf; + ssize_t len; + int status; + + status = ssam_request_sync_alloc(spec->length, GFP_KERNEL, &rqst, &buf); + if (status) + return status; + + status = ssam_request_sync_init(rqst, spec->flags); + if (status) + return status; + + ssam_request_sync_set_resp(rqst, rsp); + + len = ssam_request_write_data(&buf, ctrl, spec); + if (len < 0) { + ssam_request_sync_free(rqst); + return len; + } + + ssam_request_sync_set_data(rqst, buf.ptr, len); + + status = ssam_request_sync_submit(ctrl, rqst); + if (!status) + status = ssam_request_sync_wait(rqst); + + ssam_request_sync_free(rqst); + return status; +} +EXPORT_SYMBOL_GPL(ssam_request_sync); + +/** + * ssam_request_sync_with_buffer() - Execute a synchronous request with the + * provided buffer as back-end for the message buffer. + * @ctrl: The controller via which the request will be submitted. + * @spec: The request specification and payload. + * @rsp: The response buffer. + * @buf: The buffer for the request message data. + * + * Allocates a synchronous request struct on the stack, fully initializes it + * using the provided buffer as message data buffer, submits it, and then + * waits for its completion before returning its status. The + * SSH_COMMAND_MESSAGE_LENGTH() macro can be used to compute the required + * message buffer size. + * + * This function does essentially the same as ssam_request_sync(), but instead + * of dynamically allocating the request and message data buffer, it uses the + * provided message data buffer and stores the (small) request struct on the + * heap. + * + * Return: Returns the status of the request or any failure during setup. + */ +int ssam_request_sync_with_buffer(struct ssam_controller *ctrl, + const struct ssam_request *spec, + struct ssam_response *rsp, + struct ssam_span *buf) +{ + struct ssam_request_sync rqst; + ssize_t len; + int status; + + status = ssam_request_sync_init(&rqst, spec->flags); + if (status) + return status; + + ssam_request_sync_set_resp(&rqst, rsp); + + len = ssam_request_write_data(buf, ctrl, spec); + if (len < 0) + return len; + + ssam_request_sync_set_data(&rqst, buf->ptr, len); + + status = ssam_request_sync_submit(ctrl, &rqst); + if (!status) + status = ssam_request_sync_wait(&rqst); + + return status; +} +EXPORT_SYMBOL_GPL(ssam_request_sync_with_buffer); + + +/* -- Internal SAM requests. ------------------------------------------------ */ + +static SSAM_DEFINE_SYNC_REQUEST_R(ssam_ssh_get_firmware_version, __le32, { + .target_category = SSAM_SSH_TC_SAM, + .target_id = 0x01, + .command_id = 0x13, + .instance_id = 0x00, +}); + +static SSAM_DEFINE_SYNC_REQUEST_R(ssam_ssh_notif_display_off, u8, { + .target_category = SSAM_SSH_TC_SAM, + .target_id = 0x01, + .command_id = 0x15, + .instance_id = 0x00, +}); + +static SSAM_DEFINE_SYNC_REQUEST_R(ssam_ssh_notif_display_on, u8, { + .target_category = SSAM_SSH_TC_SAM, + .target_id = 0x01, + .command_id = 0x16, + .instance_id = 0x00, +}); + +static SSAM_DEFINE_SYNC_REQUEST_R(ssam_ssh_notif_d0_exit, u8, { + .target_category = SSAM_SSH_TC_SAM, + .target_id = 0x01, + .command_id = 0x33, + .instance_id = 0x00, +}); + +static SSAM_DEFINE_SYNC_REQUEST_R(ssam_ssh_notif_d0_entry, u8, { + .target_category = SSAM_SSH_TC_SAM, + .target_id = 0x01, + .command_id = 0x34, + .instance_id = 0x00, +}); + +/** + * struct ssh_notification_params - Command payload to enable/disable SSH + * notifications. + * @target_category: The target category for which notifications should be + * enabled/disabled. + * @flags: Flags determining how notifications are being sent. + * @request_id: The request ID that is used to send these notifications. + * @instance_id: The specific instance in the given target category for + * which notifications should be enabled. + */ +struct ssh_notification_params { + u8 target_category; + u8 flags; + __le16 request_id; + u8 instance_id; +} __packed; + +static_assert(sizeof(struct ssh_notification_params) == 5); + +static int __ssam_ssh_event_request(struct ssam_controller *ctrl, + struct ssam_event_registry reg, u8 cid, + struct ssam_event_id id, u8 flags) +{ + struct ssh_notification_params params; + struct ssam_request rqst; + struct ssam_response result; + int status; + + u16 rqid = ssh_tc_to_rqid(id.target_category); + u8 buf = 0; + + /* Only allow RQIDs that lie within the event spectrum. */ + if (!ssh_rqid_is_event(rqid)) + return -EINVAL; + + params.target_category = id.target_category; + params.instance_id = id.instance; + params.flags = flags; + put_unaligned_le16(rqid, ¶ms.request_id); + + rqst.target_category = reg.target_category; + rqst.target_id = reg.target_id; + rqst.command_id = cid; + rqst.instance_id = 0x00; + rqst.flags = SSAM_REQUEST_HAS_RESPONSE; + rqst.length = sizeof(params); + rqst.payload = (u8 *)¶ms; + + result.capacity = sizeof(buf); + result.length = 0; + result.pointer = &buf; + + status = ssam_retry(ssam_request_sync_onstack, ctrl, &rqst, &result, + sizeof(params)); + + return status < 0 ? status : buf; +} + +/** + * ssam_ssh_event_enable() - Enable SSH event. + * @ctrl: The controller for which to enable the event. + * @reg: The event registry describing what request to use for enabling and + * disabling the event. + * @id: The event identifier. + * @flags: The event flags. + * + * Enables the specified event on the EC. This function does not manage + * reference counting of enabled events and is basically only a wrapper for + * the raw EC request. If the specified event is already enabled, the EC will + * ignore this request. + * + * Return: Returns the status of the executed SAM request (zero on success and + * negative on direct failure) or %-EPROTO if the request response indicates a + * failure. + */ +static int ssam_ssh_event_enable(struct ssam_controller *ctrl, + struct ssam_event_registry reg, + struct ssam_event_id id, u8 flags) +{ + int status; + + status = __ssam_ssh_event_request(ctrl, reg, reg.cid_enable, id, flags); + + if (status < 0 && status != -EINVAL) { + ssam_err(ctrl, + "failed to enable event source (tc: %#04x, iid: %#04x, reg: %#04x)\n", + id.target_category, id.instance, reg.target_category); + } + + if (status > 0) { + ssam_err(ctrl, + "unexpected result while enabling event source: %#04x (tc: %#04x, iid: %#04x, reg: %#04x)\n", + status, id.target_category, id.instance, reg.target_category); + return -EPROTO; + } + + return status; +} + +/** + * ssam_ssh_event_disable() - Disable SSH event. + * @ctrl: The controller for which to disable the event. + * @reg: The event registry describing what request to use for enabling and + * disabling the event (must be same as used when enabling the event). + * @id: The event identifier. + * @flags: The event flags (likely ignored for disabling of events). + * + * Disables the specified event on the EC. This function does not manage + * reference counting of enabled events and is basically only a wrapper for + * the raw EC request. If the specified event is already disabled, the EC will + * ignore this request. + * + * Return: Returns the status of the executed SAM request (zero on success and + * negative on direct failure) or %-EPROTO if the request response indicates a + * failure. + */ +static int ssam_ssh_event_disable(struct ssam_controller *ctrl, + struct ssam_event_registry reg, + struct ssam_event_id id, u8 flags) +{ + int status; + + status = __ssam_ssh_event_request(ctrl, reg, reg.cid_enable, id, flags); + + if (status < 0 && status != -EINVAL) { + ssam_err(ctrl, + "failed to disable event source (tc: %#04x, iid: %#04x, reg: %#04x)\n", + id.target_category, id.instance, reg.target_category); + } + + if (status > 0) { + ssam_err(ctrl, + "unexpected result while disabling event source: %#04x (tc: %#04x, iid: %#04x, reg: %#04x)\n", + status, id.target_category, id.instance, reg.target_category); + return -EPROTO; + } + + return status; +} + + +/* -- Wrappers for internal SAM requests. ----------------------------------- */ + +/** + * ssam_get_firmware_version() - Get the SAM/EC firmware version. + * @ctrl: The controller. + * @version: Where to store the version number. + * + * Return: Returns zero on success or the status of the executed SAM request + * if that request failed. + */ +int ssam_get_firmware_version(struct ssam_controller *ctrl, u32 *version) +{ + __le32 __version; + int status; + + status = ssam_retry(ssam_ssh_get_firmware_version, ctrl, &__version); + if (status) + return status; + + *version = le32_to_cpu(__version); + return 0; +} + +/** + * ssam_ctrl_notif_display_off() - Notify EC that the display has been turned + * off. + * @ctrl: The controller. + * + * Notify the EC that the display has been turned off and the driver may enter + * a lower-power state. This will prevent events from being sent directly. + * Rather, the EC signals an event by pulling the wakeup GPIO high for as long + * as there are pending events. The events then need to be manually released, + * one by one, via the GPIO callback request. All pending events accumulated + * during this state can also be released by issuing the display-on + * notification, e.g. via ssam_ctrl_notif_display_on(), which will also reset + * the GPIO. + * + * On some devices, specifically ones with an integrated keyboard, the keyboard + * backlight will be turned off by this call. + * + * This function will only send the display-off notification command if + * display notifications are supported by the EC. Currently all known devices + * support these notifications. + * + * Use ssam_ctrl_notif_display_on() to reverse the effects of this function. + * + * Return: Returns zero on success or if no request has been executed, the + * status of the executed SAM request if that request failed, or %-EPROTO if + * an unexpected response has been received. + */ +int ssam_ctrl_notif_display_off(struct ssam_controller *ctrl) +{ + int status; + u8 response; + + ssam_dbg(ctrl, "pm: notifying display off\n"); + + status = ssam_retry(ssam_ssh_notif_display_off, ctrl, &response); + if (status) + return status; + + if (response != 0) { + ssam_err(ctrl, "unexpected response from display-off notification: %#04x\n", + response); + return -EPROTO; + } + + return 0; +} + +/** + * ssam_ctrl_notif_display_on() - Notify EC that the display has been turned on. + * @ctrl: The controller. + * + * Notify the EC that the display has been turned back on and the driver has + * exited its lower-power state. This notification is the counterpart to the + * display-off notification sent via ssam_ctrl_notif_display_off() and will + * reverse its effects, including resetting events to their default behavior. + * + * This function will only send the display-on notification command if display + * notifications are supported by the EC. Currently all known devices support + * these notifications. + * + * See ssam_ctrl_notif_display_off() for more details. + * + * Return: Returns zero on success or if no request has been executed, the + * status of the executed SAM request if that request failed, or %-EPROTO if + * an unexpected response has been received. + */ +int ssam_ctrl_notif_display_on(struct ssam_controller *ctrl) +{ + int status; + u8 response; + + ssam_dbg(ctrl, "pm: notifying display on\n"); + + status = ssam_retry(ssam_ssh_notif_display_on, ctrl, &response); + if (status) + return status; + + if (response != 0) { + ssam_err(ctrl, "unexpected response from display-on notification: %#04x\n", + response); + return -EPROTO; + } + + return 0; +} + +/** + * ssam_ctrl_notif_d0_exit() - Notify EC that the driver/device exits the D0 + * power state. + * @ctrl: The controller + * + * Notifies the EC that the driver prepares to exit the D0 power state in + * favor of a lower-power state. Exact effects of this function related to the + * EC are currently unknown. + * + * This function will only send the D0-exit notification command if D0-state + * notifications are supported by the EC. Only newer Surface generations + * support these notifications. + * + * Use ssam_ctrl_notif_d0_entry() to reverse the effects of this function. + * + * Return: Returns zero on success or if no request has been executed, the + * status of the executed SAM request if that request failed, or %-EPROTO if + * an unexpected response has been received. + */ +int ssam_ctrl_notif_d0_exit(struct ssam_controller *ctrl) +{ + int status; + u8 response; + + if (!ctrl->caps.d3_closes_handle) + return 0; + + ssam_dbg(ctrl, "pm: notifying D0 exit\n"); + + status = ssam_retry(ssam_ssh_notif_d0_exit, ctrl, &response); + if (status) + return status; + + if (response != 0) { + ssam_err(ctrl, "unexpected response from D0-exit notification: %#04x\n", + response); + return -EPROTO; + } + + return 0; +} + +/** + * ssam_ctrl_notif_d0_entry() - Notify EC that the driver/device enters the D0 + * power state. + * @ctrl: The controller + * + * Notifies the EC that the driver has exited a lower-power state and entered + * the D0 power state. Exact effects of this function related to the EC are + * currently unknown. + * + * This function will only send the D0-entry notification command if D0-state + * notifications are supported by the EC. Only newer Surface generations + * support these notifications. + * + * See ssam_ctrl_notif_d0_exit() for more details. + * + * Return: Returns zero on success or if no request has been executed, the + * status of the executed SAM request if that request failed, or %-EPROTO if + * an unexpected response has been received. + */ +int ssam_ctrl_notif_d0_entry(struct ssam_controller *ctrl) +{ + int status; + u8 response; + + if (!ctrl->caps.d3_closes_handle) + return 0; + + ssam_dbg(ctrl, "pm: notifying D0 entry\n"); + + status = ssam_retry(ssam_ssh_notif_d0_entry, ctrl, &response); + if (status) + return status; + + if (response != 0) { + ssam_err(ctrl, "unexpected response from D0-entry notification: %#04x\n", + response); + return -EPROTO; + } + + return 0; +} + + +/* -- Top-level event registry interface. ----------------------------------- */ + +/** + * ssam_notifier_register() - Register an event notifier. + * @ctrl: The controller to register the notifier on. + * @n: The event notifier to register. + * + * Register an event notifier and increment the usage counter of the + * associated SAM event. If the event was previously not enabled, it will be + * enabled during this call. + * + * Return: Returns zero on success, %-ENOSPC if there have already been + * %INT_MAX notifiers for the event ID/type associated with the notifier block + * registered, %-ENOMEM if the corresponding event entry could not be + * allocated. If this is the first time that a notifier block is registered + * for the specific associated event, returns the status of the event-enable + * EC-command. + */ +int ssam_notifier_register(struct ssam_controller *ctrl, + struct ssam_event_notifier *n) +{ + u16 rqid = ssh_tc_to_rqid(n->event.id.target_category); + struct ssam_nf_refcount_entry *entry; + struct ssam_nf_head *nf_head; + struct ssam_nf *nf; + int status; + + if (!ssh_rqid_is_event(rqid)) + return -EINVAL; + + nf = &ctrl->cplt.event.notif; + nf_head = &nf->head[ssh_rqid_to_event(rqid)]; + + mutex_lock(&nf->lock); + + entry = ssam_nf_refcount_inc(nf, n->event.reg, n->event.id); + if (IS_ERR(entry)) { + mutex_unlock(&nf->lock); + return PTR_ERR(entry); + } + + ssam_dbg(ctrl, "enabling event (reg: %#04x, tc: %#04x, iid: %#04x, rc: %d)\n", + n->event.reg.target_category, n->event.id.target_category, + n->event.id.instance, entry->refcount); + + status = ssam_nfblk_insert(nf_head, &n->base); + if (status) { + entry = ssam_nf_refcount_dec(nf, n->event.reg, n->event.id); + if (entry->refcount == 0) + kfree(entry); + + mutex_unlock(&nf->lock); + return status; + } + + if (entry->refcount == 1) { + status = ssam_ssh_event_enable(ctrl, n->event.reg, n->event.id, + n->event.flags); + if (status) { + ssam_nfblk_remove(&n->base); + kfree(ssam_nf_refcount_dec(nf, n->event.reg, n->event.id)); + mutex_unlock(&nf->lock); + synchronize_srcu(&nf_head->srcu); + return status; + } + + entry->flags = n->event.flags; + + } else if (entry->flags != n->event.flags) { + ssam_warn(ctrl, + "inconsistent flags when enabling event: got %#04x, expected %#04x (reg: %#04x, tc: %#04x, iid: %#04x)\n", + n->event.flags, entry->flags, n->event.reg.target_category, + n->event.id.target_category, n->event.id.instance); + } + + mutex_unlock(&nf->lock); + return 0; +} +EXPORT_SYMBOL_GPL(ssam_notifier_register); + +/** + * ssam_notifier_unregister() - Unregister an event notifier. + * @ctrl: The controller the notifier has been registered on. + * @n: The event notifier to unregister. + * + * Unregister an event notifier and decrement the usage counter of the + * associated SAM event. If the usage counter reaches zero, the event will be + * disabled. + * + * Return: Returns zero on success, %-ENOENT if the given notifier block has + * not been registered on the controller. If the given notifier block was the + * last one associated with its specific event, returns the status of the + * event-disable EC-command. + */ +int ssam_notifier_unregister(struct ssam_controller *ctrl, + struct ssam_event_notifier *n) +{ + u16 rqid = ssh_tc_to_rqid(n->event.id.target_category); + struct ssam_nf_refcount_entry *entry; + struct ssam_nf_head *nf_head; + struct ssam_nf *nf; + int status = 0; + + if (!ssh_rqid_is_event(rqid)) + return -EINVAL; + + nf = &ctrl->cplt.event.notif; + nf_head = &nf->head[ssh_rqid_to_event(rqid)]; + + mutex_lock(&nf->lock); + + if (!ssam_nfblk_find(nf_head, &n->base)) { + mutex_unlock(&nf->lock); + return -ENOENT; + } + + entry = ssam_nf_refcount_dec(nf, n->event.reg, n->event.id); + if (WARN_ON(!entry)) { + /* + * If this does not return an entry, there's a logic error + * somewhere: The notifier block is registered, but the event + * refcount entry is not there. Remove the notifier block + * anyways. + */ + status = -ENOENT; + goto remove; + } + + ssam_dbg(ctrl, "disabling event (reg: %#04x, tc: %#04x, iid: %#04x, rc: %d)\n", + n->event.reg.target_category, n->event.id.target_category, + n->event.id.instance, entry->refcount); + + if (entry->flags != n->event.flags) { + ssam_warn(ctrl, + "inconsistent flags when disabling event: got %#04x, expected %#04x (reg: %#04x, tc: %#04x, iid: %#04x)\n", + n->event.flags, entry->flags, n->event.reg.target_category, + n->event.id.target_category, n->event.id.instance); + } + + if (entry->refcount == 0) { + status = ssam_ssh_event_disable(ctrl, n->event.reg, n->event.id, + n->event.flags); + kfree(entry); + } + +remove: + ssam_nfblk_remove(&n->base); + mutex_unlock(&nf->lock); + synchronize_srcu(&nf_head->srcu); + + return status; +} +EXPORT_SYMBOL_GPL(ssam_notifier_unregister); + +/** + * ssam_notifier_disable_registered() - Disable events for all registered + * notifiers. + * @ctrl: The controller for which to disable the notifiers/events. + * + * Disables events for all currently registered notifiers. In case of an error + * (EC command failing), all previously disabled events will be restored and + * the error code returned. + * + * This function is intended to disable all events prior to hibernation entry. + * See ssam_notifier_restore_registered() to restore/re-enable all events + * disabled with this function. + * + * Note that this function will not disable events for notifiers registered + * after calling this function. It should thus be made sure that no new + * notifiers are going to be added after this call and before the corresponding + * call to ssam_notifier_restore_registered(). + * + * Return: Returns zero on success. In case of failure returns the error code + * returned by the failed EC command to disable an event. + */ +int ssam_notifier_disable_registered(struct ssam_controller *ctrl) +{ + struct ssam_nf *nf = &ctrl->cplt.event.notif; + struct rb_node *n; + int status; + + mutex_lock(&nf->lock); + for (n = rb_first(&nf->refcount); n; n = rb_next(n)) { + struct ssam_nf_refcount_entry *e; + + e = rb_entry(n, struct ssam_nf_refcount_entry, node); + status = ssam_ssh_event_disable(ctrl, e->key.reg, + e->key.id, e->flags); + if (status) + goto err; + } + mutex_unlock(&nf->lock); + + return 0; + +err: + for (n = rb_prev(n); n; n = rb_prev(n)) { + struct ssam_nf_refcount_entry *e; + + e = rb_entry(n, struct ssam_nf_refcount_entry, node); + ssam_ssh_event_enable(ctrl, e->key.reg, e->key.id, e->flags); + } + mutex_unlock(&nf->lock); + + return status; +} + +/** + * ssam_notifier_restore_registered() - Restore/re-enable events for all + * registered notifiers. + * @ctrl: The controller for which to restore the notifiers/events. + * + * Restores/re-enables all events for which notifiers have been registered on + * the given controller. In case of a failure, the error is logged and the + * function continues to try and enable the remaining events. + * + * This function is intended to restore/re-enable all registered events after + * hibernation. See ssam_notifier_disable_registered() for the counter part + * disabling the events and more details. + */ +void ssam_notifier_restore_registered(struct ssam_controller *ctrl) +{ + struct ssam_nf *nf = &ctrl->cplt.event.notif; + struct rb_node *n; + + mutex_lock(&nf->lock); + for (n = rb_first(&nf->refcount); n; n = rb_next(n)) { + struct ssam_nf_refcount_entry *e; + + e = rb_entry(n, struct ssam_nf_refcount_entry, node); + + /* Ignore errors, will get logged in call. */ + ssam_ssh_event_enable(ctrl, e->key.reg, e->key.id, e->flags); + } + mutex_unlock(&nf->lock); +} + +/** + * ssam_notifier_is_empty() - Check if there are any registered notifiers. + * @ctrl: The controller to check on. + * + * Return: Returns %true if there are currently no notifiers registered on the + * controller, %false otherwise. + */ +static bool ssam_notifier_is_empty(struct ssam_controller *ctrl) +{ + struct ssam_nf *nf = &ctrl->cplt.event.notif; + bool result; + + mutex_lock(&nf->lock); + result = ssam_nf_refcount_empty(nf); + mutex_unlock(&nf->lock); + + return result; +} + +/** + * ssam_notifier_unregister_all() - Unregister all currently registered + * notifiers. + * @ctrl: The controller to unregister the notifiers on. + * + * Unregisters all currently registered notifiers. This function is used to + * ensure that all notifiers will be unregistered and associated + * entries/resources freed when the controller is being shut down. + */ +static void ssam_notifier_unregister_all(struct ssam_controller *ctrl) +{ + struct ssam_nf *nf = &ctrl->cplt.event.notif; + struct ssam_nf_refcount_entry *e, *n; + + mutex_lock(&nf->lock); + rbtree_postorder_for_each_entry_safe(e, n, &nf->refcount, node) { + /* Ignore errors, will get logged in call. */ + ssam_ssh_event_disable(ctrl, e->key.reg, e->key.id, e->flags); + kfree(e); + } + nf->refcount = RB_ROOT; + mutex_unlock(&nf->lock); +} + + +/* -- Wakeup IRQ. ----------------------------------------------------------- */ + +static irqreturn_t ssam_irq_handle(int irq, void *dev_id) +{ + struct ssam_controller *ctrl = dev_id; + + ssam_dbg(ctrl, "pm: wake irq triggered\n"); + + /* + * Note: Proper wakeup detection is currently unimplemented. + * When the EC is in display-off or any other non-D0 state, it + * does not send events/notifications to the host. Instead it + * signals that there are events available via the wakeup IRQ. + * This driver is responsible for calling back to the EC to + * release these events one-by-one. + * + * This IRQ should not cause a full system resume by its own. + * Instead, events should be handled by their respective subsystem + * drivers, which in turn should signal whether a full system + * resume should be performed. + * + * TODO: Send GPIO callback command repeatedly to EC until callback + * returns 0x00. Return flag of callback is "has more events". + * Each time the command is sent, one event is "released". Once + * all events have been released (return = 0x00), the GPIO is + * re-armed. Detect wakeup events during this process, go back to + * sleep if no wakeup event has been received. + */ + + return IRQ_HANDLED; +} + +/** + * ssam_irq_setup() - Set up SAM EC wakeup-GPIO interrupt. + * @ctrl: The controller for which the IRQ should be set up. + * + * Set up an IRQ for the wakeup-GPIO pin of the SAM EC. This IRQ can be used + * to wake the device from a low power state. + * + * Note that this IRQ can only be triggered while the EC is in the display-off + * state. In this state, events are not sent to the host in the usual way. + * Instead the wakeup-GPIO gets pulled to "high" as long as there are pending + * events and these events need to be released one-by-one via the GPIO + * callback request, either until there are no events left and the GPIO is + * reset, or all at once by transitioning the EC out of the display-off state, + * which will also clear the GPIO. + * + * Not all events, however, should trigger a full system wakeup. Instead the + * driver should, if necessary, inspect and forward each event to the + * corresponding subsystem, which in turn should decide if the system needs to + * be woken up. This logic has not been implemented yet, thus wakeup by this + * IRQ should be disabled by default to avoid spurious wake-ups, caused, for + * example, by the remaining battery percentage changing. Refer to comments in + * this function and comments in the corresponding IRQ handler for more + * details on how this should be implemented. + * + * See also ssam_ctrl_notif_display_off() and ssam_ctrl_notif_display_off() + * for functions to transition the EC into and out of the display-off state as + * well as more details on it. + * + * The IRQ is disabled by default and has to be enabled before it can wake up + * the device from suspend via ssam_irq_arm_for_wakeup(). On teardown, the IRQ + * should be freed via ssam_irq_free(). + */ +int ssam_irq_setup(struct ssam_controller *ctrl) +{ + struct device *dev = ssam_controller_device(ctrl); + struct gpio_desc *gpiod; + int irq; + int status; + + /* + * The actual GPIO interrupt is declared in ACPI as TRIGGER_HIGH. + * However, the GPIO line only gets reset by sending the GPIO callback + * command to SAM (or alternatively the display-on notification). As + * proper handling for this interrupt is not implemented yet, leaving + * the IRQ at TRIGGER_HIGH would cause an IRQ storm (as the callback + * never gets sent and thus the line never gets reset). To avoid this, + * mark the IRQ as TRIGGER_RISING for now, only creating a single + * interrupt, and let the SAM resume callback during the controller + * resume process clear it. + */ + const int irqf = IRQF_SHARED | IRQF_ONESHOT | IRQF_TRIGGER_RISING; + + gpiod = gpiod_get(dev, "ssam_wakeup-int", GPIOD_ASIS); + if (IS_ERR(gpiod)) + return PTR_ERR(gpiod); + + irq = gpiod_to_irq(gpiod); + gpiod_put(gpiod); + + if (irq < 0) + return irq; + + status = request_threaded_irq(irq, NULL, ssam_irq_handle, irqf, + "ssam_wakeup", ctrl); + if (status) + return status; + + ctrl->irq.num = irq; + disable_irq(ctrl->irq.num); + return 0; +} + +/** + * ssam_irq_free() - Free SAM EC wakeup-GPIO interrupt. + * @ctrl: The controller for which the IRQ should be freed. + * + * Free the wakeup-GPIO IRQ previously set-up via ssam_irq_setup(). + */ +void ssam_irq_free(struct ssam_controller *ctrl) +{ + free_irq(ctrl->irq.num, ctrl); + ctrl->irq.num = -1; +} + +/** + * ssam_irq_arm_for_wakeup() - Arm the EC IRQ for wakeup, if enabled. + * @ctrl: The controller for which the IRQ should be armed. + * + * Sets up the IRQ so that it can be used to wake the device. Specifically, + * this function enables the irq and then, if the device is allowed to wake up + * the system, calls enable_irq_wake(). See ssam_irq_disarm_wakeup() for the + * corresponding function to disable the IRQ. + * + * This function is intended to arm the IRQ before entering S2idle suspend. + * + * Note: calls to ssam_irq_arm_for_wakeup() and ssam_irq_disarm_wakeup() must + * be balanced. + */ +int ssam_irq_arm_for_wakeup(struct ssam_controller *ctrl) +{ + struct device *dev = ssam_controller_device(ctrl); + int status; + + enable_irq(ctrl->irq.num); + if (device_may_wakeup(dev)) { + status = enable_irq_wake(ctrl->irq.num); + if (status) { + ssam_err(ctrl, "failed to enable wake IRQ: %d\n", status); + disable_irq(ctrl->irq.num); + return status; + } + + ctrl->irq.wakeup_enabled = true; + } else { + ctrl->irq.wakeup_enabled = false; + } + + return 0; +} + +/** + * ssam_irq_disarm_wakeup() - Disarm the wakeup IRQ. + * @ctrl: The controller for which the IRQ should be disarmed. + * + * Disarm the IRQ previously set up for wake via ssam_irq_arm_for_wakeup(). + * + * This function is intended to disarm the IRQ after exiting S2idle suspend. + * + * Note: calls to ssam_irq_arm_for_wakeup() and ssam_irq_disarm_wakeup() must + * be balanced. + */ +void ssam_irq_disarm_wakeup(struct ssam_controller *ctrl) +{ + int status; + + if (ctrl->irq.wakeup_enabled) { + status = disable_irq_wake(ctrl->irq.num); + if (status) + ssam_err(ctrl, "failed to disable wake IRQ: %d\n", status); + + ctrl->irq.wakeup_enabled = false; + } + disable_irq(ctrl->irq.num); +} diff --git a/drivers/platform/surface/aggregator/controller.h b/drivers/platform/surface/aggregator/controller.h new file mode 100644 index 000000000000..5ee9e966f1d7 --- /dev/null +++ b/drivers/platform/surface/aggregator/controller.h @@ -0,0 +1,276 @@ +/* SPDX-License-Identifier: GPL-2.0+ */ +/* + * Main SSAM/SSH controller structure and functionality. + * + * Copyright (C) 2019-2020 Maximilian Luz + */ + +#ifndef _SURFACE_AGGREGATOR_CONTROLLER_H +#define _SURFACE_AGGREGATOR_CONTROLLER_H + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include + +#include "ssh_request_layer.h" + + +/* -- Safe counters. -------------------------------------------------------- */ + +/** + * struct ssh_seq_counter - Safe counter for SSH sequence IDs. + * @value: The current counter value. + */ +struct ssh_seq_counter { + u8 value; +}; + +/** + * struct ssh_rqid_counter - Safe counter for SSH request IDs. + * @value: The current counter value. + */ +struct ssh_rqid_counter { + u16 value; +}; + + +/* -- Event/notification system. -------------------------------------------- */ + +/** + * struct ssam_nf_head - Notifier head for SSAM events. + * @srcu: The SRCU struct for synchronization. + * @head: List-head for notifier blocks registered under this head. + */ +struct ssam_nf_head { + struct srcu_struct srcu; + struct list_head head; +}; + +/** + * struct ssam_nf - Notifier callback- and activation-registry for SSAM events. + * @lock: Lock guarding (de-)registration of notifier blocks. Note: This + * lock does not need to be held for notifier calls, only + * registration and deregistration. + * @refcount: The root of the RB-tree used for reference-counting enabled + * events/notifications. + * @head: The list of notifier heads for event/notification callbacks. + */ +struct ssam_nf { + struct mutex lock; + struct rb_root refcount; + struct ssam_nf_head head[SSH_NUM_EVENTS]; +}; + + +/* -- Event/async request completion system. -------------------------------- */ + +struct ssam_cplt; + +/** + * struct ssam_event_item - Struct for event queuing and completion. + * @node: The node in the queue. + * @rqid: The request ID of the event. + * @event: Actual event data. + */ +struct ssam_event_item { + struct list_head node; + u16 rqid; + + struct ssam_event event; /* must be last */ +}; + +/** + * struct ssam_event_queue - Queue for completing received events. + * @cplt: Reference to the completion system on which this queue is active. + * @lock: The lock for any operation on the queue. + * @head: The list-head of the queue. + * @work: The &struct work_struct performing completion work for this queue. + */ +struct ssam_event_queue { + struct ssam_cplt *cplt; + + spinlock_t lock; + struct list_head head; + struct work_struct work; +}; + +/** + * struct ssam_event_target - Set of queues for a single SSH target ID. + * @queue: The array of queues, one queue per event ID. + */ +struct ssam_event_target { + struct ssam_event_queue queue[SSH_NUM_EVENTS]; +}; + +/** + * struct ssam_cplt - SSAM event/async request completion system. + * @dev: The device with which this system is associated. Only used + * for logging. + * @wq: The &struct workqueue_struct on which all completion work + * items are queued. + * @event: Event completion management. + * @event.target: Array of &struct ssam_event_target, one for each target. + * @event.notif: Notifier callbacks and event activation reference counting. + */ +struct ssam_cplt { + struct device *dev; + struct workqueue_struct *wq; + + struct { + struct ssam_event_target target[SSH_NUM_TARGETS]; + struct ssam_nf notif; + } event; +}; + + +/* -- Main SSAM device structures. ------------------------------------------ */ + +/** + * enum ssam_controller_state - State values for &struct ssam_controller. + * @SSAM_CONTROLLER_UNINITIALIZED: + * The controller has not been initialized yet or has been deinitialized. + * @SSAM_CONTROLLER_INITIALIZED: + * The controller is initialized, but has not been started yet. + * @SSAM_CONTROLLER_STARTED: + * The controller has been started and is ready to use. + * @SSAM_CONTROLLER_STOPPED: + * The controller has been stopped. + * @SSAM_CONTROLLER_SUSPENDED: + * The controller has been suspended. + */ +enum ssam_controller_state { + SSAM_CONTROLLER_UNINITIALIZED, + SSAM_CONTROLLER_INITIALIZED, + SSAM_CONTROLLER_STARTED, + SSAM_CONTROLLER_STOPPED, + SSAM_CONTROLLER_SUSPENDED, +}; + +/** + * struct ssam_controller_caps - Controller device capabilities. + * @ssh_power_profile: SSH power profile. + * @ssh_buffer_size: SSH driver UART buffer size. + * @screen_on_sleep_idle_timeout: SAM UART screen-on sleep idle timeout. + * @screen_off_sleep_idle_timeout: SAM UART screen-off sleep idle timeout. + * @d3_closes_handle: SAM closes UART handle in D3. + * + * Controller and SSH device capabilities found in ACPI. + */ +struct ssam_controller_caps { + u32 ssh_power_profile; + u32 ssh_buffer_size; + u32 screen_on_sleep_idle_timeout; + u32 screen_off_sleep_idle_timeout; + u32 d3_closes_handle:1; +}; + +/** + * struct ssam_controller - SSAM controller device. + * @kref: Reference count of the controller. + * @lock: Main lock for the controller, used to guard state changes. + * @state: Controller state. + * @rtl: Request transport layer for SSH I/O. + * @cplt: Completion system for SSH/SSAM events and asynchronous requests. + * @counter: Safe SSH message ID counters. + * @counter.seq: Sequence ID counter. + * @counter.rqid: Request ID counter. + * @irq: Wakeup IRQ resources. + * @irq.num: The wakeup IRQ number. + * @irq.wakeup_enabled: Whether wakeup by IRQ is enabled during suspend. + * @caps: The controller device capabilities. + */ +struct ssam_controller { + struct kref kref; + + struct rw_semaphore lock; + enum ssam_controller_state state; + + struct ssh_rtl rtl; + struct ssam_cplt cplt; + + struct { + struct ssh_seq_counter seq; + struct ssh_rqid_counter rqid; + } counter; + + struct { + int num; + bool wakeup_enabled; + } irq; + + struct ssam_controller_caps caps; +}; + +#define to_ssam_controller(ptr, member) \ + container_of(ptr, struct ssam_controller, member) + +#define ssam_dbg(ctrl, fmt, ...) rtl_dbg(&(ctrl)->rtl, fmt, ##__VA_ARGS__) +#define ssam_info(ctrl, fmt, ...) rtl_info(&(ctrl)->rtl, fmt, ##__VA_ARGS__) +#define ssam_warn(ctrl, fmt, ...) rtl_warn(&(ctrl)->rtl, fmt, ##__VA_ARGS__) +#define ssam_err(ctrl, fmt, ...) rtl_err(&(ctrl)->rtl, fmt, ##__VA_ARGS__) + +/** + * ssam_controller_receive_buf() - Provide input-data to the controller. + * @ctrl: The controller. + * @buf: The input buffer. + * @n: The number of bytes in the input buffer. + * + * Provide input data to be evaluated by the controller, which has been + * received via the lower-level transport. + * + * Return: Returns the number of bytes consumed, or, if the packet transport + * layer of the controller has been shut down, %-ESHUTDOWN. + */ +static inline +int ssam_controller_receive_buf(struct ssam_controller *ctrl, + const unsigned char *buf, size_t n) +{ + return ssh_ptl_rx_rcvbuf(&ctrl->rtl.ptl, buf, n); +} + +/** + * ssam_controller_write_wakeup() - Notify the controller that the underlying + * device has space available for data to be written. + * @ctrl: The controller. + */ +static inline void ssam_controller_write_wakeup(struct ssam_controller *ctrl) +{ + ssh_ptl_tx_wakeup_transfer(&ctrl->rtl.ptl); +} + +int ssam_controller_init(struct ssam_controller *ctrl, struct serdev_device *s); +int ssam_controller_start(struct ssam_controller *ctrl); +void ssam_controller_shutdown(struct ssam_controller *ctrl); +void ssam_controller_destroy(struct ssam_controller *ctrl); + +int ssam_notifier_disable_registered(struct ssam_controller *ctrl); +void ssam_notifier_restore_registered(struct ssam_controller *ctrl); + +int ssam_irq_setup(struct ssam_controller *ctrl); +void ssam_irq_free(struct ssam_controller *ctrl); +int ssam_irq_arm_for_wakeup(struct ssam_controller *ctrl); +void ssam_irq_disarm_wakeup(struct ssam_controller *ctrl); + +void ssam_controller_lock(struct ssam_controller *c); +void ssam_controller_unlock(struct ssam_controller *c); + +int ssam_get_firmware_version(struct ssam_controller *ctrl, u32 *version); +int ssam_ctrl_notif_display_off(struct ssam_controller *ctrl); +int ssam_ctrl_notif_display_on(struct ssam_controller *ctrl); +int ssam_ctrl_notif_d0_exit(struct ssam_controller *ctrl); +int ssam_ctrl_notif_d0_entry(struct ssam_controller *ctrl); + +int ssam_controller_suspend(struct ssam_controller *ctrl); +int ssam_controller_resume(struct ssam_controller *ctrl); + +#endif /* _SURFACE_AGGREGATOR_CONTROLLER_H */ diff --git a/drivers/platform/surface/aggregator/core.c b/drivers/platform/surface/aggregator/core.c new file mode 100644 index 000000000000..18e0e9e34e7b --- /dev/null +++ b/drivers/platform/surface/aggregator/core.c @@ -0,0 +1,787 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Surface Serial Hub (SSH) driver for communication with the Surface/System + * Aggregator Module (SSAM/SAM). + * + * Provides access to a SAM-over-SSH connected EC via a controller device. + * Handles communication via requests as well as enabling, disabling, and + * relaying of events. + * + * Copyright (C) 2019-2020 Maximilian Luz + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include "controller.h" + + +/* -- Static controller reference. ------------------------------------------ */ + +/* + * Main controller reference. The corresponding lock must be held while + * accessing (reading/writing) the reference. + */ +static struct ssam_controller *__ssam_controller; +static DEFINE_SPINLOCK(__ssam_controller_lock); + +/** + * ssam_get_controller() - Get reference to SSAM controller. + * + * Returns a reference to the SSAM controller of the system or %NULL if there + * is none, it hasn't been set up yet, or it has already been unregistered. + * This function automatically increments the reference count of the + * controller, thus the calling party must ensure that ssam_controller_put() + * is called when it doesn't need the controller any more. + */ +struct ssam_controller *ssam_get_controller(void) +{ + struct ssam_controller *ctrl; + + spin_lock(&__ssam_controller_lock); + + ctrl = __ssam_controller; + if (!ctrl) + goto out; + + if (WARN_ON(!kref_get_unless_zero(&ctrl->kref))) + ctrl = NULL; + +out: + spin_unlock(&__ssam_controller_lock); + return ctrl; +} +EXPORT_SYMBOL_GPL(ssam_get_controller); + +/** + * ssam_try_set_controller() - Try to set the main controller reference. + * @ctrl: The controller to which the reference should point. + * + * Set the main controller reference to the given pointer if the reference + * hasn't been set already. + * + * Return: Returns zero on success or %-EEXIST if the reference has already + * been set. + */ +static int ssam_try_set_controller(struct ssam_controller *ctrl) +{ + int status = 0; + + spin_lock(&__ssam_controller_lock); + if (!__ssam_controller) + __ssam_controller = ctrl; + else + status = -EEXIST; + spin_unlock(&__ssam_controller_lock); + + return status; +} + +/** + * ssam_clear_controller() - Remove/clear the main controller reference. + * + * Clears the main controller reference, i.e. sets it to %NULL. This function + * should be called before the controller is shut down. + */ +static void ssam_clear_controller(void) +{ + spin_lock(&__ssam_controller_lock); + __ssam_controller = NULL; + spin_unlock(&__ssam_controller_lock); +} + +/** + * ssam_client_link() - Link an arbitrary client device to the controller. + * @c: The controller to link to. + * @client: The client device. + * + * Link an arbitrary client device to the controller by creating a device link + * between it as consumer and the controller device as provider. This function + * can be used for non-SSAM devices (or SSAM devices not registered as child + * under the controller) to guarantee that the controller is valid for as long + * as the driver of the client device is bound, and that proper suspend and + * resume ordering is guaranteed. + * + * The device link does not have to be destructed manually. It is removed + * automatically once the driver of the client device unbinds. + * + * Return: Returns zero on success, %-ENODEV if the controller is not ready or + * going to be removed soon, or %-ENOMEM if the device link could not be + * created for other reasons. + */ +int ssam_client_link(struct ssam_controller *c, struct device *client) +{ + const u32 flags = DL_FLAG_PM_RUNTIME | DL_FLAG_AUTOREMOVE_CONSUMER; + struct device_link *link; + struct device *ctrldev; + + ssam_controller_statelock(c); + + if (c->state != SSAM_CONTROLLER_STARTED) { + ssam_controller_stateunlock(c); + return -ENODEV; + } + + ctrldev = ssam_controller_device(c); + if (!ctrldev) { + ssam_controller_stateunlock(c); + return -ENODEV; + } + + link = device_link_add(client, ctrldev, flags); + if (!link) { + ssam_controller_stateunlock(c); + return -ENOMEM; + } + + /* + * Return -ENODEV if supplier driver is on its way to be removed. In + * this case, the controller won't be around for much longer and the + * device link is not going to save us any more, as unbinding is + * already in progress. + */ + if (READ_ONCE(link->status) == DL_STATE_SUPPLIER_UNBIND) { + ssam_controller_stateunlock(c); + return -ENODEV; + } + + ssam_controller_stateunlock(c); + return 0; +} +EXPORT_SYMBOL_GPL(ssam_client_link); + +/** + * ssam_client_bind() - Bind an arbitrary client device to the controller. + * @client: The client device. + * + * Link an arbitrary client device to the controller by creating a device link + * between it as consumer and the main controller device as provider. This + * function can be used for non-SSAM devices to guarantee that the controller + * returned by this function is valid for as long as the driver of the client + * device is bound, and that proper suspend and resume ordering is guaranteed. + * + * This function does essentially the same as ssam_client_link(), except that + * it first fetches the main controller reference, then creates the link, and + * finally returns this reference. Note that this function does not increment + * the reference counter of the controller, as, due to the link, the + * controller lifetime is assured as long as the driver of the client device + * is bound. + * + * It is not valid to use the controller reference obtained by this method + * outside of the driver bound to the client device at the time of calling + * this function, without first incrementing the reference count of the + * controller via ssam_controller_get(). Even after doing this, care must be + * taken that requests are only submitted and notifiers are only + * (un-)registered when the controller is active and not suspended. In other + * words: The device link only lives as long as the client driver is bound and + * any guarantees enforced by this link (e.g. active controller state) can + * only be relied upon as long as this link exists and may need to be enforced + * in other ways afterwards. + * + * The created device link does not have to be destructed manually. It is + * removed automatically once the driver of the client device unbinds. + * + * Return: Returns the controller on success, an error pointer with %-ENODEV + * if the controller is not present, not ready or going to be removed soon, or + * %-ENOMEM if the device link could not be created for other reasons. + */ +struct ssam_controller *ssam_client_bind(struct device *client) +{ + struct ssam_controller *c; + int status; + + c = ssam_get_controller(); + if (!c) + return ERR_PTR(-ENODEV); + + status = ssam_client_link(c, client); + + /* + * Note that we can drop our controller reference in both success and + * failure cases: On success, we have bound the controller lifetime + * inherently to the client driver lifetime, i.e. it the controller is + * now guaranteed to outlive the client driver. On failure, we're not + * going to use the controller any more. + */ + ssam_controller_put(c); + + return status >= 0 ? c : ERR_PTR(status); +} +EXPORT_SYMBOL_GPL(ssam_client_bind); + + +/* -- Glue layer (serdev_device -> ssam_controller). ------------------------ */ + +static int ssam_receive_buf(struct serdev_device *dev, const unsigned char *buf, + size_t n) +{ + struct ssam_controller *ctrl; + + ctrl = serdev_device_get_drvdata(dev); + return ssam_controller_receive_buf(ctrl, buf, n); +} + +static void ssam_write_wakeup(struct serdev_device *dev) +{ + ssam_controller_write_wakeup(serdev_device_get_drvdata(dev)); +} + +static const struct serdev_device_ops ssam_serdev_ops = { + .receive_buf = ssam_receive_buf, + .write_wakeup = ssam_write_wakeup, +}; + + +/* -- SysFS and misc. ------------------------------------------------------- */ + +static int ssam_log_firmware_version(struct ssam_controller *ctrl) +{ + u32 version, a, b, c; + int status; + + status = ssam_get_firmware_version(ctrl, &version); + if (status) + return status; + + a = (version >> 24) & 0xff; + b = ((version >> 8) & 0xffff); + c = version & 0xff; + + ssam_info(ctrl, "SAM firmware version: %u.%u.%u\n", a, b, c); + return 0; +} + +static ssize_t firmware_version_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct ssam_controller *ctrl = dev_get_drvdata(dev); + u32 version, a, b, c; + int status; + + status = ssam_get_firmware_version(ctrl, &version); + if (status < 0) + return status; + + a = (version >> 24) & 0xff; + b = ((version >> 8) & 0xffff); + c = version & 0xff; + + return sysfs_emit(buf, "%u.%u.%u\n", a, b, c); +} +static DEVICE_ATTR_RO(firmware_version); + +static struct attribute *ssam_sam_attrs[] = { + &dev_attr_firmware_version.attr, + NULL +}; + +static const struct attribute_group ssam_sam_group = { + .name = "sam", + .attrs = ssam_sam_attrs, +}; + + +/* -- ACPI based device setup. ---------------------------------------------- */ + +static acpi_status ssam_serdev_setup_via_acpi_crs(struct acpi_resource *rsc, + void *ctx) +{ + struct serdev_device *serdev = ctx; + struct acpi_resource_common_serialbus *serial; + struct acpi_resource_uart_serialbus *uart; + bool flow_control; + int status = 0; + + if (rsc->type != ACPI_RESOURCE_TYPE_SERIAL_BUS) + return AE_OK; + + serial = &rsc->data.common_serial_bus; + if (serial->type != ACPI_RESOURCE_SERIAL_TYPE_UART) + return AE_OK; + + uart = &rsc->data.uart_serial_bus; + + /* Set up serdev device. */ + serdev_device_set_baudrate(serdev, uart->default_baud_rate); + + /* serdev currently only supports RTSCTS flow control. */ + if (uart->flow_control & (~((u8)ACPI_UART_FLOW_CONTROL_HW))) { + dev_warn(&serdev->dev, "setup: unsupported flow control (value: %#04x)\n", + uart->flow_control); + } + + /* Set RTSCTS flow control. */ + flow_control = uart->flow_control & ACPI_UART_FLOW_CONTROL_HW; + serdev_device_set_flow_control(serdev, flow_control); + + /* serdev currently only supports EVEN/ODD parity. */ + switch (uart->parity) { + case ACPI_UART_PARITY_NONE: + status = serdev_device_set_parity(serdev, SERDEV_PARITY_NONE); + break; + case ACPI_UART_PARITY_EVEN: + status = serdev_device_set_parity(serdev, SERDEV_PARITY_EVEN); + break; + case ACPI_UART_PARITY_ODD: + status = serdev_device_set_parity(serdev, SERDEV_PARITY_ODD); + break; + default: + dev_warn(&serdev->dev, "setup: unsupported parity (value: %#04x)\n", + uart->parity); + break; + } + + if (status) { + dev_err(&serdev->dev, "setup: failed to set parity (value: %#04x, error: %d)\n", + uart->parity, status); + return AE_ERROR; + } + + /* We've found the resource and are done. */ + return AE_CTRL_TERMINATE; +} + +static acpi_status ssam_serdev_setup_via_acpi(acpi_handle handle, + struct serdev_device *serdev) +{ + return acpi_walk_resources(handle, METHOD_NAME__CRS, + ssam_serdev_setup_via_acpi_crs, serdev); +} + + +/* -- Power management. ----------------------------------------------------- */ + +static void ssam_serial_hub_shutdown(struct device *dev) +{ + struct ssam_controller *c = dev_get_drvdata(dev); + int status; + + /* + * Try to disable notifiers, signal display-off and D0-exit, ignore any + * errors. + * + * Note: It has not been established yet if this is actually + * necessary/useful for shutdown. + */ + + status = ssam_notifier_disable_registered(c); + if (status) { + ssam_err(c, "pm: failed to disable notifiers for shutdown: %d\n", + status); + } + + status = ssam_ctrl_notif_display_off(c); + if (status) + ssam_err(c, "pm: display-off notification failed: %d\n", status); + + status = ssam_ctrl_notif_d0_exit(c); + if (status) + ssam_err(c, "pm: D0-exit notification failed: %d\n", status); +} + +#ifdef CONFIG_PM_SLEEP + +static int ssam_serial_hub_pm_prepare(struct device *dev) +{ + struct ssam_controller *c = dev_get_drvdata(dev); + int status; + + /* + * Try to signal display-off, This will quiesce events. + * + * Note: Signaling display-off/display-on should normally be done from + * some sort of display state notifier. As that is not available, + * signal it here. + */ + + status = ssam_ctrl_notif_display_off(c); + if (status) + ssam_err(c, "pm: display-off notification failed: %d\n", status); + + return status; +} + +static void ssam_serial_hub_pm_complete(struct device *dev) +{ + struct ssam_controller *c = dev_get_drvdata(dev); + int status; + + /* + * Try to signal display-on. This will restore events. + * + * Note: Signaling display-off/display-on should normally be done from + * some sort of display state notifier. As that is not available, + * signal it here. + */ + + status = ssam_ctrl_notif_display_on(c); + if (status) + ssam_err(c, "pm: display-on notification failed: %d\n", status); +} + +static int ssam_serial_hub_pm_suspend(struct device *dev) +{ + struct ssam_controller *c = dev_get_drvdata(dev); + int status; + + /* + * Try to signal D0-exit, enable IRQ wakeup if specified. Abort on + * error. + */ + + status = ssam_ctrl_notif_d0_exit(c); + if (status) { + ssam_err(c, "pm: D0-exit notification failed: %d\n", status); + goto err_notif; + } + + status = ssam_irq_arm_for_wakeup(c); + if (status) + goto err_irq; + + WARN_ON(ssam_controller_suspend(c)); + return 0; + +err_irq: + ssam_ctrl_notif_d0_entry(c); +err_notif: + ssam_ctrl_notif_display_on(c); + return status; +} + +static int ssam_serial_hub_pm_resume(struct device *dev) +{ + struct ssam_controller *c = dev_get_drvdata(dev); + int status; + + WARN_ON(ssam_controller_resume(c)); + + /* + * Try to disable IRQ wakeup (if specified) and signal D0-entry. In + * case of errors, log them and try to restore normal operation state + * as far as possible. + * + * Note: Signaling display-off/display-on should normally be done from + * some sort of display state notifier. As that is not available, + * signal it here. + */ + + ssam_irq_disarm_wakeup(c); + + status = ssam_ctrl_notif_d0_entry(c); + if (status) + ssam_err(c, "pm: D0-entry notification failed: %d\n", status); + + return 0; +} + +static int ssam_serial_hub_pm_freeze(struct device *dev) +{ + struct ssam_controller *c = dev_get_drvdata(dev); + int status; + + /* + * During hibernation image creation, we only have to ensure that the + * EC doesn't send us any events. This is done via the display-off + * and D0-exit notifications. Note that this sets up the wakeup IRQ + * on the EC side, however, we have disabled it by default on our side + * and won't enable it here. + * + * See ssam_serial_hub_poweroff() for more details on the hibernation + * process. + */ + + status = ssam_ctrl_notif_d0_exit(c); + if (status) { + ssam_err(c, "pm: D0-exit notification failed: %d\n", status); + ssam_ctrl_notif_display_on(c); + return status; + } + + WARN_ON(ssam_controller_suspend(c)); + return 0; +} + +static int ssam_serial_hub_pm_thaw(struct device *dev) +{ + struct ssam_controller *c = dev_get_drvdata(dev); + int status; + + WARN_ON(ssam_controller_resume(c)); + + status = ssam_ctrl_notif_d0_entry(c); + if (status) + ssam_err(c, "pm: D0-exit notification failed: %d\n", status); + + return status; +} + +static int ssam_serial_hub_pm_poweroff(struct device *dev) +{ + struct ssam_controller *c = dev_get_drvdata(dev); + int status; + + /* + * When entering hibernation and powering off the system, the EC, at + * least on some models, may disable events. Without us taking care of + * that, this leads to events not being enabled/restored when the + * system resumes from hibernation, resulting SAM-HID subsystem devices + * (i.e. keyboard, touchpad) not working, AC-plug/AC-unplug events being + * gone, etc. + * + * To avoid these issues, we disable all registered events here (this is + * likely not actually required) and restore them during the drivers PM + * restore callback. + * + * Wakeup from the EC interrupt is not supported during hibernation, + * so don't arm the IRQ here. + */ + + status = ssam_notifier_disable_registered(c); + if (status) { + ssam_err(c, "pm: failed to disable notifiers for hibernation: %d\n", + status); + return status; + } + + status = ssam_ctrl_notif_d0_exit(c); + if (status) { + ssam_err(c, "pm: D0-exit notification failed: %d\n", status); + ssam_notifier_restore_registered(c); + return status; + } + + WARN_ON(ssam_controller_suspend(c)); + return 0; +} + +static int ssam_serial_hub_pm_restore(struct device *dev) +{ + struct ssam_controller *c = dev_get_drvdata(dev); + int status; + + /* + * Ignore but log errors, try to restore state as much as possible in + * case of failures. See ssam_serial_hub_poweroff() for more details on + * the hibernation process. + */ + + WARN_ON(ssam_controller_resume(c)); + + status = ssam_ctrl_notif_d0_entry(c); + if (status) + ssam_err(c, "pm: D0-entry notification failed: %d\n", status); + + ssam_notifier_restore_registered(c); + return 0; +} + +static const struct dev_pm_ops ssam_serial_hub_pm_ops = { + .prepare = ssam_serial_hub_pm_prepare, + .complete = ssam_serial_hub_pm_complete, + .suspend = ssam_serial_hub_pm_suspend, + .resume = ssam_serial_hub_pm_resume, + .freeze = ssam_serial_hub_pm_freeze, + .thaw = ssam_serial_hub_pm_thaw, + .poweroff = ssam_serial_hub_pm_poweroff, + .restore = ssam_serial_hub_pm_restore, +}; + +#else /* CONFIG_PM_SLEEP */ + +static const struct dev_pm_ops ssam_serial_hub_pm_ops = { }; + +#endif /* CONFIG_PM_SLEEP */ + + +/* -- Device/driver setup. -------------------------------------------------- */ + +static const struct acpi_gpio_params gpio_ssam_wakeup_int = { 0, 0, false }; +static const struct acpi_gpio_params gpio_ssam_wakeup = { 1, 0, false }; + +static const struct acpi_gpio_mapping ssam_acpi_gpios[] = { + { "ssam_wakeup-int-gpio", &gpio_ssam_wakeup_int, 1 }, + { "ssam_wakeup-gpio", &gpio_ssam_wakeup, 1 }, + { }, +}; + +static int ssam_serial_hub_probe(struct serdev_device *serdev) +{ + struct ssam_controller *ctrl; + acpi_handle *ssh = ACPI_HANDLE(&serdev->dev); + acpi_status astatus; + int status; + + if (gpiod_count(&serdev->dev, NULL) < 0) + return -ENODEV; + + status = devm_acpi_dev_add_driver_gpios(&serdev->dev, ssam_acpi_gpios); + if (status) + return status; + + /* Allocate controller. */ + ctrl = kzalloc(sizeof(*ctrl), GFP_KERNEL); + if (!ctrl) + return -ENOMEM; + + /* Initialize controller. */ + status = ssam_controller_init(ctrl, serdev); + if (status) + goto err_ctrl_init; + + ssam_controller_lock(ctrl); + + /* Set up serdev device. */ + serdev_device_set_drvdata(serdev, ctrl); + serdev_device_set_client_ops(serdev, &ssam_serdev_ops); + status = serdev_device_open(serdev); + if (status) + goto err_devopen; + + astatus = ssam_serdev_setup_via_acpi(ssh, serdev); + if (ACPI_FAILURE(astatus)) { + status = -ENXIO; + goto err_devinit; + } + + /* Start controller. */ + status = ssam_controller_start(ctrl); + if (status) + goto err_devinit; + + ssam_controller_unlock(ctrl); + + /* + * Initial SAM requests: Log version and notify default/init power + * states. + */ + status = ssam_log_firmware_version(ctrl); + if (status) + goto err_initrq; + + status = ssam_ctrl_notif_d0_entry(ctrl); + if (status) + goto err_initrq; + + status = ssam_ctrl_notif_display_on(ctrl); + if (status) + goto err_initrq; + + status = sysfs_create_group(&serdev->dev.kobj, &ssam_sam_group); + if (status) + goto err_initrq; + + /* Set up IRQ. */ + status = ssam_irq_setup(ctrl); + if (status) + goto err_irq; + + /* Finally, set main controller reference. */ + status = ssam_try_set_controller(ctrl); + if (WARN_ON(status)) /* Currently, we're the only provider. */ + goto err_mainref; + + /* + * TODO: The EC can wake up the system via the associated GPIO interrupt + * in multiple situations. One of which is the remaining battery + * capacity falling below a certain threshold. Normally, we should + * use the device_init_wakeup function, however, the EC also seems + * to have other reasons for waking up the system and it seems + * that Windows has additional checks whether the system should be + * resumed. In short, this causes some spurious unwanted wake-ups. + * For now let's thus default power/wakeup to false. + */ + device_set_wakeup_capable(&serdev->dev, true); + acpi_walk_dep_device_list(ssh); + + return 0; + +err_mainref: + ssam_irq_free(ctrl); +err_irq: + sysfs_remove_group(&serdev->dev.kobj, &ssam_sam_group); +err_initrq: + ssam_controller_lock(ctrl); + ssam_controller_shutdown(ctrl); +err_devinit: + serdev_device_close(serdev); +err_devopen: + ssam_controller_destroy(ctrl); + ssam_controller_unlock(ctrl); +err_ctrl_init: + kfree(ctrl); + return status; +} + +static void ssam_serial_hub_remove(struct serdev_device *serdev) +{ + struct ssam_controller *ctrl = serdev_device_get_drvdata(serdev); + int status; + + /* Clear static reference so that no one else can get a new one. */ + ssam_clear_controller(); + + /* Disable and free IRQ. */ + ssam_irq_free(ctrl); + + sysfs_remove_group(&serdev->dev.kobj, &ssam_sam_group); + ssam_controller_lock(ctrl); + + /* Act as if suspending to silence events. */ + status = ssam_ctrl_notif_display_off(ctrl); + if (status) { + dev_err(&serdev->dev, "display-off notification failed: %d\n", + status); + } + + status = ssam_ctrl_notif_d0_exit(ctrl); + if (status) { + dev_err(&serdev->dev, "D0-exit notification failed: %d\n", + status); + } + + /* Shut down controller and remove serdev device reference from it. */ + ssam_controller_shutdown(ctrl); + + /* Shut down actual transport. */ + serdev_device_wait_until_sent(serdev, 0); + serdev_device_close(serdev); + + /* Drop our controller reference. */ + ssam_controller_unlock(ctrl); + ssam_controller_put(ctrl); + + device_set_wakeup_capable(&serdev->dev, false); +} + +static const struct acpi_device_id ssam_serial_hub_match[] = { + { "MSHW0084", 0 }, + { }, +}; +MODULE_DEVICE_TABLE(acpi, ssam_serial_hub_match); + +static struct serdev_device_driver ssam_serial_hub = { + .probe = ssam_serial_hub_probe, + .remove = ssam_serial_hub_remove, + .driver = { + .name = "surface_serial_hub", + .acpi_match_table = ssam_serial_hub_match, + .pm = &ssam_serial_hub_pm_ops, + .shutdown = ssam_serial_hub_shutdown, + .probe_type = PROBE_PREFER_ASYNCHRONOUS, + }, +}; +module_serdev_device_driver(ssam_serial_hub); + +MODULE_AUTHOR("Maximilian Luz "); +MODULE_DESCRIPTION("Subsystem and Surface Serial Hub driver for Surface System Aggregator Module"); +MODULE_LICENSE("GPL"); diff --git a/drivers/platform/surface/aggregator/ssh_msgb.h b/drivers/platform/surface/aggregator/ssh_msgb.h new file mode 100644 index 000000000000..1221f642dda1 --- /dev/null +++ b/drivers/platform/surface/aggregator/ssh_msgb.h @@ -0,0 +1,205 @@ +/* SPDX-License-Identifier: GPL-2.0+ */ +/* + * SSH message builder functions. + * + * Copyright (C) 2019-2020 Maximilian Luz + */ + +#ifndef _SURFACE_AGGREGATOR_SSH_MSGB_H +#define _SURFACE_AGGREGATOR_SSH_MSGB_H + +#include +#include + +#include +#include + +/** + * struct msgbuf - Buffer struct to construct SSH messages. + * @begin: Pointer to the beginning of the allocated buffer space. + * @end: Pointer to the end (one past last element) of the allocated buffer + * space. + * @ptr: Pointer to the first free element in the buffer. + */ +struct msgbuf { + u8 *begin; + u8 *end; + u8 *ptr; +}; + +/** + * msgb_init() - Initialize the given message buffer struct. + * @msgb: The buffer struct to initialize + * @ptr: Pointer to the underlying memory by which the buffer will be backed. + * @cap: Size of the underlying memory. + * + * Initialize the given message buffer struct using the provided memory as + * backing. + */ +static inline void msgb_init(struct msgbuf *msgb, u8 *ptr, size_t cap) +{ + msgb->begin = ptr; + msgb->end = ptr + cap; + msgb->ptr = ptr; +} + +/** + * msgb_bytes_used() - Return the current number of bytes used in the buffer. + * @msgb: The message buffer. + */ +static inline size_t msgb_bytes_used(const struct msgbuf *msgb) +{ + return msgb->ptr - msgb->begin; +} + +static inline void __msgb_push_u8(struct msgbuf *msgb, u8 value) +{ + *msgb->ptr = value; + msgb->ptr += sizeof(u8); +} + +static inline void __msgb_push_u16(struct msgbuf *msgb, u16 value) +{ + put_unaligned_le16(value, msgb->ptr); + msgb->ptr += sizeof(u16); +} + +/** + * msgb_push_u16() - Push a u16 value to the buffer. + * @msgb: The message buffer. + * @value: The value to push to the buffer. + */ +static inline void msgb_push_u16(struct msgbuf *msgb, u16 value) +{ + if (WARN_ON(msgb->ptr + sizeof(u16) > msgb->end)) + return; + + __msgb_push_u16(msgb, value); +} + +/** + * msgb_push_syn() - Push SSH SYN bytes to the buffer. + * @msgb: The message buffer. + */ +static inline void msgb_push_syn(struct msgbuf *msgb) +{ + msgb_push_u16(msgb, SSH_MSG_SYN); +} + +/** + * msgb_push_buf() - Push raw data to the buffer. + * @msgb: The message buffer. + * @buf: The data to push to the buffer. + * @len: The length of the data to push to the buffer. + */ +static inline void msgb_push_buf(struct msgbuf *msgb, const u8 *buf, size_t len) +{ + msgb->ptr = memcpy(msgb->ptr, buf, len) + len; +} + +/** + * msgb_push_crc() - Compute CRC and push it to the buffer. + * @msgb: The message buffer. + * @buf: The data for which the CRC should be computed. + * @len: The length of the data for which the CRC should be computed. + */ +static inline void msgb_push_crc(struct msgbuf *msgb, const u8 *buf, size_t len) +{ + msgb_push_u16(msgb, ssh_crc(buf, len)); +} + +/** + * msgb_push_frame() - Push a SSH message frame header to the buffer. + * @msgb: The message buffer + * @ty: The type of the frame. + * @len: The length of the payload of the frame. + * @seq: The sequence ID of the frame/packet. + */ +static inline void msgb_push_frame(struct msgbuf *msgb, u8 ty, u16 len, u8 seq) +{ + u8 *const begin = msgb->ptr; + + if (WARN_ON(msgb->ptr + sizeof(struct ssh_frame) > msgb->end)) + return; + + __msgb_push_u8(msgb, ty); /* Frame type. */ + __msgb_push_u16(msgb, len); /* Frame payload length. */ + __msgb_push_u8(msgb, seq); /* Frame sequence ID. */ + + msgb_push_crc(msgb, begin, msgb->ptr - begin); +} + +/** + * msgb_push_ack() - Push a SSH ACK frame to the buffer. + * @msgb: The message buffer + * @seq: The sequence ID of the frame/packet to be ACKed. + */ +static inline void msgb_push_ack(struct msgbuf *msgb, u8 seq) +{ + /* SYN. */ + msgb_push_syn(msgb); + + /* ACK-type frame + CRC. */ + msgb_push_frame(msgb, SSH_FRAME_TYPE_ACK, 0x00, seq); + + /* Payload CRC (ACK-type frames do not have a payload). */ + msgb_push_crc(msgb, msgb->ptr, 0); +} + +/** + * msgb_push_nak() - Push a SSH NAK frame to the buffer. + * @msgb: The message buffer + */ +static inline void msgb_push_nak(struct msgbuf *msgb) +{ + /* SYN. */ + msgb_push_syn(msgb); + + /* NAK-type frame + CRC. */ + msgb_push_frame(msgb, SSH_FRAME_TYPE_NAK, 0x00, 0x00); + + /* Payload CRC (ACK-type frames do not have a payload). */ + msgb_push_crc(msgb, msgb->ptr, 0); +} + +/** + * msgb_push_cmd() - Push a SSH command frame with payload to the buffer. + * @msgb: The message buffer. + * @seq: The sequence ID (SEQ) of the frame/packet. + * @rqid: The request ID (RQID) of the request contained in the frame. + * @rqst: The request to wrap in the frame. + */ +static inline void msgb_push_cmd(struct msgbuf *msgb, u8 seq, u16 rqid, + const struct ssam_request *rqst) +{ + const u8 type = SSH_FRAME_TYPE_DATA_SEQ; + u8 *cmd; + + /* SYN. */ + msgb_push_syn(msgb); + + /* Command frame + CRC. */ + msgb_push_frame(msgb, type, sizeof(struct ssh_command) + rqst->length, seq); + + /* Frame payload: Command struct + payload. */ + if (WARN_ON(msgb->ptr + sizeof(struct ssh_command) > msgb->end)) + return; + + cmd = msgb->ptr; + + __msgb_push_u8(msgb, SSH_PLD_TYPE_CMD); /* Payload type. */ + __msgb_push_u8(msgb, rqst->target_category); /* Target category. */ + __msgb_push_u8(msgb, rqst->target_id); /* Target ID (out). */ + __msgb_push_u8(msgb, 0x00); /* Target ID (in). */ + __msgb_push_u8(msgb, rqst->instance_id); /* Instance ID. */ + __msgb_push_u16(msgb, rqid); /* Request ID. */ + __msgb_push_u8(msgb, rqst->command_id); /* Command ID. */ + + /* Command payload. */ + msgb_push_buf(msgb, rqst->payload, rqst->length); + + /* CRC for command struct + payload. */ + msgb_push_crc(msgb, cmd, msgb->ptr - cmd); +} + +#endif /* _SURFACE_AGGREGATOR_SSH_MSGB_H */ diff --git a/drivers/platform/surface/aggregator/ssh_packet_layer.c b/drivers/platform/surface/aggregator/ssh_packet_layer.c new file mode 100644 index 000000000000..66e38fdc7963 --- /dev/null +++ b/drivers/platform/surface/aggregator/ssh_packet_layer.c @@ -0,0 +1,1710 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * SSH packet transport layer. + * + * Copyright (C) 2019-2020 Maximilian Luz + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include + +#include "ssh_msgb.h" +#include "ssh_packet_layer.h" +#include "ssh_parser.h" + +/* + * To simplify reasoning about the code below, we define a few concepts. The + * system below is similar to a state-machine for packets, however, there are + * too many states to explicitly write them down. To (somewhat) manage the + * states and packets we rely on flags, reference counting, and some simple + * concepts. State transitions are triggered by actions. + * + * >> Actions << + * + * - submit + * - transmission start (process next item in queue) + * - transmission finished (guaranteed to never be parallel to transmission + * start) + * - ACK received + * - NAK received (this is equivalent to issuing re-submit for all pending + * packets) + * - timeout (this is equivalent to re-issuing a submit or canceling) + * - cancel (non-pending and pending) + * + * >> Data Structures, Packet Ownership, General Overview << + * + * The code below employs two main data structures: The packet queue, + * containing all packets scheduled for transmission, and the set of pending + * packets, containing all packets awaiting an ACK. + * + * Shared ownership of a packet is controlled via reference counting. Inside + * the transport system are a total of five packet owners: + * + * - the packet queue, + * - the pending set, + * - the transmitter thread, + * - the receiver thread (via ACKing), and + * - the timeout work item. + * + * Normal operation is as follows: The initial reference of the packet is + * obtained by submitting the packet and queuing it. The receiver thread takes + * packets from the queue. By doing this, it does not increment the refcount + * but takes over the reference (removing it from the queue). If the packet is + * sequenced (i.e. needs to be ACKed by the client), the transmitter thread + * sets-up the timeout and adds the packet to the pending set before starting + * to transmit it. As the timeout is handled by a reaper task, no additional + * reference for it is needed. After the transmit is done, the reference held + * by the transmitter thread is dropped. If the packet is unsequenced (i.e. + * does not need an ACK), the packet is completed by the transmitter thread + * before dropping that reference. + * + * On receival of an ACK, the receiver thread removes and obtains the + * reference to the packet from the pending set. The receiver thread will then + * complete the packet and drop its reference. + * + * On receival of a NAK, the receiver thread re-submits all currently pending + * packets. + * + * Packet timeouts are detected by the timeout reaper. This is a task, + * scheduled depending on the earliest packet timeout expiration date, + * checking all currently pending packets if their timeout has expired. If the + * timeout of a packet has expired, it is re-submitted and the number of tries + * of this packet is incremented. If this number reaches its limit, the packet + * will be completed with a failure. + * + * On transmission failure (such as repeated packet timeouts), the completion + * callback is immediately run by on thread on which the error was detected. + * + * To ensure that a packet eventually leaves the system it is marked as + * "locked" directly before it is going to be completed or when it is + * canceled. Marking a packet as "locked" has the effect that passing and + * creating new references of the packet is disallowed. This means that the + * packet cannot be added to the queue, the pending set, and the timeout, or + * be picked up by the transmitter thread or receiver thread. To remove a + * packet from the system it has to be marked as locked and subsequently all + * references from the data structures (queue, pending) have to be removed. + * References held by threads will eventually be dropped automatically as + * their execution progresses. + * + * Note that the packet completion callback is, in case of success and for a + * sequenced packet, guaranteed to run on the receiver thread, thus providing + * a way to reliably identify responses to the packet. The packet completion + * callback is only run once and it does not indicate that the packet has + * fully left the system (for this, one should rely on the release method, + * triggered when the reference count of the packet reaches zero). In case of + * re-submission (and with somewhat unlikely timing), it may be possible that + * the packet is being re-transmitted while the completion callback runs. + * Completion will occur both on success and internal error, as well as when + * the packet is canceled. + * + * >> Flags << + * + * Flags are used to indicate the state and progression of a packet. Some flags + * have stricter guarantees than other: + * + * - locked + * Indicates if the packet is locked. If the packet is locked, passing and/or + * creating additional references to the packet is forbidden. The packet thus + * may not be queued, dequeued, or removed or added to the pending set. Note + * that the packet state flags may still change (e.g. it may be marked as + * ACKed, transmitted, ...). + * + * - completed + * Indicates if the packet completion callback has been executed or is about + * to be executed. This flag is used to ensure that the packet completion + * callback is only run once. + * + * - queued + * Indicates if a packet is present in the submission queue or not. This flag + * must only be modified with the queue lock held, and must be coherent to the + * presence of the packet in the queue. + * + * - pending + * Indicates if a packet is present in the set of pending packets or not. + * This flag must only be modified with the pending lock held, and must be + * coherent to the presence of the packet in the pending set. + * + * - transmitting + * Indicates if the packet is currently transmitting. In case of + * re-transmissions, it is only safe to wait on the "transmitted" completion + * after this flag has been set. The completion will be set both in success + * and error case. + * + * - transmitted + * Indicates if the packet has been transmitted. This flag is not cleared by + * the system, thus it indicates the first transmission only. + * + * - acked + * Indicates if the packet has been acknowledged by the client. There are no + * other guarantees given. For example, the packet may still be canceled + * and/or the completion may be triggered an error even though this bit is + * set. Rely on the status provided to the completion callback instead. + * + * - canceled + * Indicates if the packet has been canceled from the outside. There are no + * other guarantees given. Specifically, the packet may be completed by + * another part of the system before the cancellation attempts to complete it. + * + * >> General Notes << + * + * - To avoid deadlocks, if both queue and pending locks are required, the + * pending lock must be acquired before the queue lock. + * + * - The packet priority must be accessed only while holding the queue lock. + * + * - The packet timestamp must be accessed only while holding the pending + * lock. + */ + +/* + * SSH_PTL_MAX_PACKET_TRIES - Maximum transmission attempts for packet. + * + * Maximum number of transmission attempts per sequenced packet in case of + * time-outs. Must be smaller than 16. If the packet times out after this + * amount of tries, the packet will be completed with %-ETIMEDOUT as status + * code. + */ +#define SSH_PTL_MAX_PACKET_TRIES 3 + +/* + * SSH_PTL_TX_TIMEOUT - Packet transmission timeout. + * + * Timeout in jiffies for packet transmission via the underlying serial + * device. If transmitting the packet takes longer than this timeout, the + * packet will be completed with -ETIMEDOUT. It will not be re-submitted. + */ +#define SSH_PTL_TX_TIMEOUT HZ + +/* + * SSH_PTL_PACKET_TIMEOUT - Packet response timeout. + * + * Timeout as ktime_t delta for ACKs. If we have not received an ACK in this + * time-frame after starting transmission, the packet will be re-submitted. + */ +#define SSH_PTL_PACKET_TIMEOUT ms_to_ktime(1000) + +/* + * SSH_PTL_PACKET_TIMEOUT_RESOLUTION - Packet timeout granularity. + * + * Time-resolution for timeouts. Should be larger than one jiffy to avoid + * direct re-scheduling of reaper work_struct. + */ +#define SSH_PTL_PACKET_TIMEOUT_RESOLUTION ms_to_ktime(max(2000 / HZ, 50)) + +/* + * SSH_PTL_MAX_PENDING - Maximum number of pending packets. + * + * Maximum number of sequenced packets concurrently waiting for an ACK. + * Packets marked as blocking will not be transmitted while this limit is + * reached. + */ +#define SSH_PTL_MAX_PENDING 1 + +/* + * SSH_PTL_RX_BUF_LEN - Evaluation-buffer size in bytes. + */ +#define SSH_PTL_RX_BUF_LEN 4096 + +/* + * SSH_PTL_RX_FIFO_LEN - Fifo input-buffer size in bytes. + */ +#define SSH_PTL_RX_FIFO_LEN 4096 + +static void __ssh_ptl_packet_release(struct kref *kref) +{ + struct ssh_packet *p = container_of(kref, struct ssh_packet, refcnt); + + ptl_dbg_cond(p->ptl, "ptl: releasing packet %p\n", p); + p->ops->release(p); +} + +/** + * ssh_packet_get() - Increment reference count of packet. + * @packet: The packet to increment the reference count of. + * + * Increments the reference count of the given packet. See ssh_packet_put() + * for the counter-part of this function. + * + * Return: Returns the packet provided as input. + */ +struct ssh_packet *ssh_packet_get(struct ssh_packet *packet) +{ + if (packet) + kref_get(&packet->refcnt); + return packet; +} +EXPORT_SYMBOL_GPL(ssh_packet_get); + +/** + * ssh_packet_put() - Decrement reference count of packet. + * @packet: The packet to decrement the reference count of. + * + * If the reference count reaches zero, the ``release`` callback specified in + * the packet's &struct ssh_packet_ops, i.e. ``packet->ops->release``, will be + * called. + * + * See ssh_packet_get() for the counter-part of this function. + */ +void ssh_packet_put(struct ssh_packet *packet) +{ + if (packet) + kref_put(&packet->refcnt, __ssh_ptl_packet_release); +} +EXPORT_SYMBOL_GPL(ssh_packet_put); + +static u8 ssh_packet_get_seq(struct ssh_packet *packet) +{ + return packet->data.ptr[SSH_MSGOFFSET_FRAME(seq)]; +} + +/** + * ssh_packet_init() - Initialize SSH packet. + * @packet: The packet to initialize. + * @type: Type-flags of the packet. + * @priority: Priority of the packet. See SSH_PACKET_PRIORITY() for details. + * @ops: Packet operations. + * + * Initializes the given SSH packet. Sets the transmission buffer pointer to + * %NULL and the transmission buffer length to zero. For data-type packets, + * this buffer has to be set separately via ssh_packet_set_data() before + * submission, and must contain a valid SSH message, i.e. frame with optional + * payload of any type. + */ +void ssh_packet_init(struct ssh_packet *packet, unsigned long type, + u8 priority, const struct ssh_packet_ops *ops) +{ + kref_init(&packet->refcnt); + + packet->ptl = NULL; + INIT_LIST_HEAD(&packet->queue_node); + INIT_LIST_HEAD(&packet->pending_node); + + packet->state = type & SSH_PACKET_FLAGS_TY_MASK; + packet->priority = priority; + packet->timestamp = KTIME_MAX; + + packet->data.ptr = NULL; + packet->data.len = 0; + + packet->ops = ops; +} + +/** + * ssh_ctrl_packet_alloc() - Allocate control packet. + * @packet: Where the pointer to the newly allocated packet should be stored. + * @buffer: The buffer corresponding to this packet. + * @flags: Flags used for allocation. + * + * Allocates a packet and corresponding transport buffer. Sets the packet's + * buffer reference to the allocated buffer. The packet must be freed via + * ssh_ctrl_packet_free(), which will also free the corresponding buffer. The + * corresponding buffer must not be freed separately. Intended to be used with + * %ssh_ptl_ctrl_packet_ops as packet operations. + * + * Return: Returns zero on success, %-ENOMEM if the allocation failed. + */ +static int ssh_ctrl_packet_alloc(struct ssh_packet **packet, + struct ssam_span *buffer, gfp_t flags) +{ + *packet = kzalloc(sizeof(**packet) + SSH_MSG_LEN_CTRL, flags); + if (!*packet) + return -ENOMEM; + + buffer->ptr = (u8 *)(*packet + 1); + buffer->len = SSH_MSG_LEN_CTRL; + + return 0; +} + +/** + * ssh_ctrl_packet_free() - Free control packet. + * @p: The packet to free. + */ +static void ssh_ctrl_packet_free(struct ssh_packet *p) +{ + kfree(p); +} + +static const struct ssh_packet_ops ssh_ptl_ctrl_packet_ops = { + .complete = NULL, + .release = ssh_ctrl_packet_free, +}; + +static void ssh_ptl_timeout_reaper_mod(struct ssh_ptl *ptl, ktime_t now, + ktime_t expires) +{ + unsigned long delta = msecs_to_jiffies(ktime_ms_delta(expires, now)); + ktime_t aexp = ktime_add(expires, SSH_PTL_PACKET_TIMEOUT_RESOLUTION); + + spin_lock(&ptl->rtx_timeout.lock); + + /* Re-adjust / schedule reaper only if it is above resolution delta. */ + if (ktime_before(aexp, ptl->rtx_timeout.expires)) { + ptl->rtx_timeout.expires = expires; + mod_delayed_work(system_wq, &ptl->rtx_timeout.reaper, delta); + } + + spin_unlock(&ptl->rtx_timeout.lock); +} + +/* Must be called with queue lock held. */ +static void ssh_packet_next_try(struct ssh_packet *p) +{ + u8 base = ssh_packet_priority_get_base(p->priority); + u8 try = ssh_packet_priority_get_try(p->priority); + + lockdep_assert_held(&p->ptl->queue.lock); + + p->priority = __SSH_PACKET_PRIORITY(base, try + 1); +} + +/* Must be called with queue lock held. */ +static struct list_head *__ssh_ptl_queue_find_entrypoint(struct ssh_packet *p) +{ + struct list_head *head; + struct ssh_packet *q; + + lockdep_assert_held(&p->ptl->queue.lock); + + /* + * We generally assume that there are less control (ACK/NAK) packets + * and re-submitted data packets as there are normal data packets (at + * least in situations in which many packets are queued; if there + * aren't many packets queued the decision on how to iterate should be + * basically irrelevant; the number of control/data packets is more or + * less limited via the maximum number of pending packets). Thus, when + * inserting a control or re-submitted data packet, (determined by + * their priority), we search from front to back. Normal data packets + * are, usually queued directly at the tail of the queue, so for those + * search from back to front. + */ + + if (p->priority > SSH_PACKET_PRIORITY(DATA, 0)) { + list_for_each(head, &p->ptl->queue.head) { + q = list_entry(head, struct ssh_packet, queue_node); + + if (q->priority < p->priority) + break; + } + } else { + list_for_each_prev(head, &p->ptl->queue.head) { + q = list_entry(head, struct ssh_packet, queue_node); + + if (q->priority >= p->priority) { + head = head->next; + break; + } + } + } + + return head; +} + +/* Must be called with queue lock held. */ +static int __ssh_ptl_queue_push(struct ssh_packet *packet) +{ + struct ssh_ptl *ptl = packet->ptl; + struct list_head *head; + + lockdep_assert_held(&ptl->queue.lock); + + if (test_bit(SSH_PTL_SF_SHUTDOWN_BIT, &ptl->state)) + return -ESHUTDOWN; + + /* Avoid further transitions when canceling/completing. */ + if (test_bit(SSH_PACKET_SF_LOCKED_BIT, &packet->state)) + return -EINVAL; + + /* If this packet has already been queued, do not add it. */ + if (test_and_set_bit(SSH_PACKET_SF_QUEUED_BIT, &packet->state)) + return -EALREADY; + + head = __ssh_ptl_queue_find_entrypoint(packet); + + list_add_tail(&ssh_packet_get(packet)->queue_node, head); + return 0; +} + +static int ssh_ptl_queue_push(struct ssh_packet *packet) +{ + int status; + + spin_lock(&packet->ptl->queue.lock); + status = __ssh_ptl_queue_push(packet); + spin_unlock(&packet->ptl->queue.lock); + + return status; +} + +static void ssh_ptl_queue_remove(struct ssh_packet *packet) +{ + struct ssh_ptl *ptl = packet->ptl; + + spin_lock(&ptl->queue.lock); + + if (!test_and_clear_bit(SSH_PACKET_SF_QUEUED_BIT, &packet->state)) { + spin_unlock(&ptl->queue.lock); + return; + } + + list_del(&packet->queue_node); + + spin_unlock(&ptl->queue.lock); + ssh_packet_put(packet); +} + +static void ssh_ptl_pending_push(struct ssh_packet *p) +{ + struct ssh_ptl *ptl = p->ptl; + const ktime_t timestamp = ktime_get_coarse_boottime(); + const ktime_t timeout = ptl->rtx_timeout.timeout; + + /* + * Note: We can get the time for the timestamp before acquiring the + * lock as this is the only place we're setting it and this function + * is called only from the transmitter thread. Thus it is not possible + * to overwrite the timestamp with an outdated value below. + */ + + spin_lock(&ptl->pending.lock); + + /* If we are canceling/completing this packet, do not add it. */ + if (test_bit(SSH_PACKET_SF_LOCKED_BIT, &p->state)) { + spin_unlock(&ptl->pending.lock); + return; + } + + /* + * On re-submission, the packet has already been added the pending + * set. We still need to update the timestamp as the packet timeout is + * reset for each (re-)submission. + */ + p->timestamp = timestamp; + + /* In case it is already pending (e.g. re-submission), do not add it. */ + if (!test_and_set_bit(SSH_PACKET_SF_PENDING_BIT, &p->state)) { + atomic_inc(&ptl->pending.count); + list_add_tail(&ssh_packet_get(p)->pending_node, &ptl->pending.head); + } + + spin_unlock(&ptl->pending.lock); + + /* Arm/update timeout reaper. */ + ssh_ptl_timeout_reaper_mod(ptl, timestamp, timestamp + timeout); +} + +static void ssh_ptl_pending_remove(struct ssh_packet *packet) +{ + struct ssh_ptl *ptl = packet->ptl; + + spin_lock(&ptl->pending.lock); + + if (!test_and_clear_bit(SSH_PACKET_SF_PENDING_BIT, &packet->state)) { + spin_unlock(&ptl->pending.lock); + return; + } + + list_del(&packet->pending_node); + atomic_dec(&ptl->pending.count); + + spin_unlock(&ptl->pending.lock); + + ssh_packet_put(packet); +} + +/* Warning: Does not check/set "completed" bit. */ +static void __ssh_ptl_complete(struct ssh_packet *p, int status) +{ + struct ssh_ptl *ptl = READ_ONCE(p->ptl); + + ptl_dbg_cond(ptl, "ptl: completing packet %p (status: %d)\n", p, status); + + if (p->ops->complete) + p->ops->complete(p, status); +} + +static void ssh_ptl_remove_and_complete(struct ssh_packet *p, int status) +{ + /* + * A call to this function should in general be preceded by + * set_bit(SSH_PACKET_SF_LOCKED_BIT, &p->flags) to avoid re-adding the + * packet to the structures it's going to be removed from. + * + * The set_bit call does not need explicit memory barriers as the + * implicit barrier of the test_and_set_bit() call below ensure that the + * flag is visible before we actually attempt to remove the packet. + */ + + if (test_and_set_bit(SSH_PACKET_SF_COMPLETED_BIT, &p->state)) + return; + + ssh_ptl_queue_remove(p); + ssh_ptl_pending_remove(p); + + __ssh_ptl_complete(p, status); +} + +static bool ssh_ptl_tx_can_process(struct ssh_packet *packet) +{ + struct ssh_ptl *ptl = packet->ptl; + + if (test_bit(SSH_PACKET_TY_FLUSH_BIT, &packet->state)) + return !atomic_read(&ptl->pending.count); + + /* We can always process non-blocking packets. */ + if (!test_bit(SSH_PACKET_TY_BLOCKING_BIT, &packet->state)) + return true; + + /* If we are already waiting for this packet, send it again. */ + if (test_bit(SSH_PACKET_SF_PENDING_BIT, &packet->state)) + return true; + + /* Otherwise: Check if we have the capacity to send. */ + return atomic_read(&ptl->pending.count) < SSH_PTL_MAX_PENDING; +} + +static struct ssh_packet *ssh_ptl_tx_pop(struct ssh_ptl *ptl) +{ + struct ssh_packet *packet = ERR_PTR(-ENOENT); + struct ssh_packet *p, *n; + + spin_lock(&ptl->queue.lock); + list_for_each_entry_safe(p, n, &ptl->queue.head, queue_node) { + /* + * If we are canceling or completing this packet, ignore it. + * It's going to be removed from this queue shortly. + */ + if (test_bit(SSH_PACKET_SF_LOCKED_BIT, &p->state)) + continue; + + /* + * Packets should be ordered non-blocking/to-be-resent first. + * If we cannot process this packet, assume that we can't + * process any following packet either and abort. + */ + if (!ssh_ptl_tx_can_process(p)) { + packet = ERR_PTR(-EBUSY); + break; + } + + /* + * We are allowed to change the state now. Remove it from the + * queue and mark it as being transmitted. + */ + + list_del(&p->queue_node); + + set_bit(SSH_PACKET_SF_TRANSMITTING_BIT, &p->state); + /* Ensure that state never gets zero. */ + smp_mb__before_atomic(); + clear_bit(SSH_PACKET_SF_QUEUED_BIT, &p->state); + + /* + * Update number of tries. This directly influences the + * priority in case the packet is re-submitted (e.g. via + * timeout/NAK). Note that all reads and writes to the + * priority after the first submission are guarded by the + * queue lock. + */ + ssh_packet_next_try(p); + + packet = p; + break; + } + spin_unlock(&ptl->queue.lock); + + return packet; +} + +static struct ssh_packet *ssh_ptl_tx_next(struct ssh_ptl *ptl) +{ + struct ssh_packet *p; + + p = ssh_ptl_tx_pop(ptl); + if (IS_ERR(p)) + return p; + + if (test_bit(SSH_PACKET_TY_SEQUENCED_BIT, &p->state)) { + ptl_dbg(ptl, "ptl: transmitting sequenced packet %p\n", p); + ssh_ptl_pending_push(p); + } else { + ptl_dbg(ptl, "ptl: transmitting non-sequenced packet %p\n", p); + } + + return p; +} + +static void ssh_ptl_tx_compl_success(struct ssh_packet *packet) +{ + struct ssh_ptl *ptl = packet->ptl; + + ptl_dbg(ptl, "ptl: successfully transmitted packet %p\n", packet); + + /* Transition state to "transmitted". */ + set_bit(SSH_PACKET_SF_TRANSMITTED_BIT, &packet->state); + /* Ensure that state never gets zero. */ + smp_mb__before_atomic(); + clear_bit(SSH_PACKET_SF_TRANSMITTING_BIT, &packet->state); + + /* If the packet is unsequenced, we're done: Lock and complete. */ + if (!test_bit(SSH_PACKET_TY_SEQUENCED_BIT, &packet->state)) { + set_bit(SSH_PACKET_SF_LOCKED_BIT, &packet->state); + ssh_ptl_remove_and_complete(packet, 0); + } + + /* + * Notify that a packet transmission has finished. In general we're only + * waiting for one packet (if any), so wake_up_all should be fine. + */ + wake_up_all(&ptl->tx.packet_wq); +} + +static void ssh_ptl_tx_compl_error(struct ssh_packet *packet, int status) +{ + /* Transmission failure: Lock the packet and try to complete it. */ + set_bit(SSH_PACKET_SF_LOCKED_BIT, &packet->state); + /* Ensure that state never gets zero. */ + smp_mb__before_atomic(); + clear_bit(SSH_PACKET_SF_TRANSMITTING_BIT, &packet->state); + + ptl_err(packet->ptl, "ptl: transmission error: %d\n", status); + ptl_dbg(packet->ptl, "ptl: failed to transmit packet: %p\n", packet); + + ssh_ptl_remove_and_complete(packet, status); + + /* + * Notify that a packet transmission has finished. In general we're only + * waiting for one packet (if any), so wake_up_all should be fine. + */ + wake_up_all(&packet->ptl->tx.packet_wq); +} + +static long ssh_ptl_tx_wait_packet(struct ssh_ptl *ptl) +{ + int status; + + status = wait_for_completion_interruptible(&ptl->tx.thread_cplt_pkt); + reinit_completion(&ptl->tx.thread_cplt_pkt); + + /* + * Ensure completion is cleared before continuing to avoid lost update + * problems. + */ + smp_mb__after_atomic(); + + return status; +} + +static long ssh_ptl_tx_wait_transfer(struct ssh_ptl *ptl, long timeout) +{ + long status; + + status = wait_for_completion_interruptible_timeout(&ptl->tx.thread_cplt_tx, + timeout); + reinit_completion(&ptl->tx.thread_cplt_tx); + + /* + * Ensure completion is cleared before continuing to avoid lost update + * problems. + */ + smp_mb__after_atomic(); + + return status; +} + +static int ssh_ptl_tx_packet(struct ssh_ptl *ptl, struct ssh_packet *packet) +{ + long timeout = SSH_PTL_TX_TIMEOUT; + size_t offset = 0; + + /* Note: Flush-packets don't have any data. */ + if (unlikely(!packet->data.ptr)) + return 0; + + ptl_dbg(ptl, "tx: sending data (length: %zu)\n", packet->data.len); + print_hex_dump_debug("tx: ", DUMP_PREFIX_OFFSET, 16, 1, + packet->data.ptr, packet->data.len, false); + + do { + ssize_t status, len; + u8 *buf; + + buf = packet->data.ptr + offset; + len = packet->data.len - offset; + + status = serdev_device_write_buf(ptl->serdev, buf, len); + if (status < 0) + return status; + + if (status == len) + return 0; + + offset += status; + + timeout = ssh_ptl_tx_wait_transfer(ptl, timeout); + if (kthread_should_stop() || !atomic_read(&ptl->tx.running)) + return -ESHUTDOWN; + + if (timeout < 0) + return -EINTR; + + if (timeout == 0) + return -ETIMEDOUT; + } while (true); +} + +static int ssh_ptl_tx_threadfn(void *data) +{ + struct ssh_ptl *ptl = data; + + while (!kthread_should_stop() && atomic_read(&ptl->tx.running)) { + struct ssh_packet *packet; + int status; + + /* Try to get the next packet. */ + packet = ssh_ptl_tx_next(ptl); + + /* If no packet can be processed, we are done. */ + if (IS_ERR(packet)) { + ssh_ptl_tx_wait_packet(ptl); + continue; + } + + /* Transfer and complete packet. */ + status = ssh_ptl_tx_packet(ptl, packet); + if (status) + ssh_ptl_tx_compl_error(packet, status); + else + ssh_ptl_tx_compl_success(packet); + + ssh_packet_put(packet); + } + + return 0; +} + +/** + * ssh_ptl_tx_wakeup_packet() - Wake up packet transmitter thread for new + * packet. + * @ptl: The packet transport layer. + * + * Wakes up the packet transmitter thread, notifying it that a new packet has + * arrived and is ready for transfer. If the packet transport layer has been + * shut down, calls to this function will be ignored. + */ +static void ssh_ptl_tx_wakeup_packet(struct ssh_ptl *ptl) +{ + if (test_bit(SSH_PTL_SF_SHUTDOWN_BIT, &ptl->state)) + return; + + complete(&ptl->tx.thread_cplt_pkt); +} + +/** + * ssh_ptl_tx_start() - Start packet transmitter thread. + * @ptl: The packet transport layer. + * + * Return: Returns zero on success, a negative error code on failure. + */ +int ssh_ptl_tx_start(struct ssh_ptl *ptl) +{ + atomic_set_release(&ptl->tx.running, 1); + + ptl->tx.thread = kthread_run(ssh_ptl_tx_threadfn, ptl, "ssam_serial_hub-tx"); + if (IS_ERR(ptl->tx.thread)) + return PTR_ERR(ptl->tx.thread); + + return 0; +} + +/** + * ssh_ptl_tx_stop() - Stop packet transmitter thread. + * @ptl: The packet transport layer. + * + * Return: Returns zero on success, a negative error code on failure. + */ +int ssh_ptl_tx_stop(struct ssh_ptl *ptl) +{ + int status = 0; + + if (!IS_ERR_OR_NULL(ptl->tx.thread)) { + /* Tell thread to stop. */ + atomic_set_release(&ptl->tx.running, 0); + + /* + * Wake up thread in case it is paused. Do not use wakeup + * helpers as this may be called when the shutdown bit has + * already been set. + */ + complete(&ptl->tx.thread_cplt_pkt); + complete(&ptl->tx.thread_cplt_tx); + + /* Finally, wait for thread to stop. */ + status = kthread_stop(ptl->tx.thread); + ptl->tx.thread = NULL; + } + + return status; +} + +static struct ssh_packet *ssh_ptl_ack_pop(struct ssh_ptl *ptl, u8 seq_id) +{ + struct ssh_packet *packet = ERR_PTR(-ENOENT); + struct ssh_packet *p, *n; + + spin_lock(&ptl->pending.lock); + list_for_each_entry_safe(p, n, &ptl->pending.head, pending_node) { + /* + * We generally expect packets to be in order, so first packet + * to be added to pending is first to be sent, is first to be + * ACKed. + */ + if (unlikely(ssh_packet_get_seq(p) != seq_id)) + continue; + + /* + * In case we receive an ACK while handling a transmission + * error completion. The packet will be removed shortly. + */ + if (unlikely(test_bit(SSH_PACKET_SF_LOCKED_BIT, &p->state))) { + packet = ERR_PTR(-EPERM); + break; + } + + /* + * Mark the packet as ACKed and remove it from pending by + * removing its node and decrementing the pending counter. + */ + set_bit(SSH_PACKET_SF_ACKED_BIT, &p->state); + /* Ensure that state never gets zero. */ + smp_mb__before_atomic(); + clear_bit(SSH_PACKET_SF_PENDING_BIT, &p->state); + + atomic_dec(&ptl->pending.count); + list_del(&p->pending_node); + packet = p; + + break; + } + spin_unlock(&ptl->pending.lock); + + return packet; +} + +static void ssh_ptl_wait_until_transmitted(struct ssh_packet *packet) +{ + wait_event(packet->ptl->tx.packet_wq, + test_bit(SSH_PACKET_SF_TRANSMITTED_BIT, &packet->state) || + test_bit(SSH_PACKET_SF_LOCKED_BIT, &packet->state)); +} + +static void ssh_ptl_acknowledge(struct ssh_ptl *ptl, u8 seq) +{ + struct ssh_packet *p; + + p = ssh_ptl_ack_pop(ptl, seq); + if (IS_ERR(p)) { + if (PTR_ERR(p) == -ENOENT) { + /* + * The packet has not been found in the set of pending + * packets. + */ + ptl_warn(ptl, "ptl: received ACK for non-pending packet\n"); + } else { + /* + * The packet is pending, but we are not allowed to take + * it because it has been locked. + */ + WARN_ON(PTR_ERR(p) != -EPERM); + } + return; + } + + ptl_dbg(ptl, "ptl: received ACK for packet %p\n", p); + + /* + * It is possible that the packet has been transmitted, but the state + * has not been updated from "transmitting" to "transmitted" yet. + * In that case, we need to wait for this transition to occur in order + * to determine between success or failure. + * + * On transmission failure, the packet will be locked after this call. + * On success, the transmitted bit will be set. + */ + ssh_ptl_wait_until_transmitted(p); + + /* + * The packet will already be locked in case of a transmission error or + * cancellation. Let the transmitter or cancellation issuer complete the + * packet. + */ + if (unlikely(test_and_set_bit(SSH_PACKET_SF_LOCKED_BIT, &p->state))) { + if (unlikely(!test_bit(SSH_PACKET_SF_TRANSMITTED_BIT, &p->state))) + ptl_err(ptl, "ptl: received ACK before packet had been fully transmitted\n"); + + ssh_packet_put(p); + return; + } + + ssh_ptl_remove_and_complete(p, 0); + ssh_packet_put(p); + + if (atomic_read(&ptl->pending.count) < SSH_PTL_MAX_PENDING) + ssh_ptl_tx_wakeup_packet(ptl); +} + +/** + * ssh_ptl_submit() - Submit a packet to the transport layer. + * @ptl: The packet transport layer to submit the packet to. + * @p: The packet to submit. + * + * Submits a new packet to the transport layer, queuing it to be sent. This + * function should not be used for re-submission. + * + * Return: Returns zero on success, %-EINVAL if a packet field is invalid or + * the packet has been canceled prior to submission, %-EALREADY if the packet + * has already been submitted, or %-ESHUTDOWN if the packet transport layer + * has been shut down. + */ +int ssh_ptl_submit(struct ssh_ptl *ptl, struct ssh_packet *p) +{ + struct ssh_ptl *ptl_old; + int status; + + /* Validate packet fields. */ + if (test_bit(SSH_PACKET_TY_FLUSH_BIT, &p->state)) { + if (p->data.ptr || test_bit(SSH_PACKET_TY_SEQUENCED_BIT, &p->state)) + return -EINVAL; + } else if (!p->data.ptr) { + return -EINVAL; + } + + /* + * The ptl reference only gets set on or before the first submission. + * After the first submission, it has to be read-only. + * + * Note that ptl may already be set from upper-layer request + * submission, thus we cannot expect it to be NULL. + */ + ptl_old = READ_ONCE(p->ptl); + if (!ptl_old) + WRITE_ONCE(p->ptl, ptl); + else if (WARN_ON(ptl_old != ptl)) + return -EALREADY; /* Submitted on different PTL. */ + + status = ssh_ptl_queue_push(p); + if (status) + return status; + + if (!test_bit(SSH_PACKET_TY_BLOCKING_BIT, &p->state) || + (atomic_read(&ptl->pending.count) < SSH_PTL_MAX_PENDING)) + ssh_ptl_tx_wakeup_packet(ptl); + + return 0; +} + +/* + * __ssh_ptl_resubmit() - Re-submit a packet to the transport layer. + * @packet: The packet to re-submit. + * + * Re-submits the given packet: Checks if it can be re-submitted and queues it + * if it can, resetting the packet timestamp in the process. Must be called + * with the pending lock held. + * + * Return: Returns %-ECANCELED if the packet has exceeded its number of tries, + * %-EINVAL if the packet has been locked, %-EALREADY if the packet is already + * on the queue, and %-ESHUTDOWN if the transmission layer has been shut down. + */ +static int __ssh_ptl_resubmit(struct ssh_packet *packet) +{ + int status; + u8 try; + + lockdep_assert_held(&packet->ptl->pending.lock); + + spin_lock(&packet->ptl->queue.lock); + + /* Check if the packet is out of tries. */ + try = ssh_packet_priority_get_try(packet->priority); + if (try >= SSH_PTL_MAX_PACKET_TRIES) { + spin_unlock(&packet->ptl->queue.lock); + return -ECANCELED; + } + + status = __ssh_ptl_queue_push(packet); + if (status) { + /* + * An error here indicates that the packet has either already + * been queued, been locked, or the transport layer is being + * shut down. In all cases: Ignore the error. + */ + spin_unlock(&packet->ptl->queue.lock); + return status; + } + + packet->timestamp = KTIME_MAX; + + spin_unlock(&packet->ptl->queue.lock); + return 0; +} + +static void ssh_ptl_resubmit_pending(struct ssh_ptl *ptl) +{ + struct ssh_packet *p; + bool resub = false; + + /* + * Note: We deliberately do not remove/attempt to cancel and complete + * packets that are out of tires in this function. The packet will be + * eventually canceled and completed by the timeout. Removing the packet + * here could lead to overly eager cancellation if the packet has not + * been re-transmitted yet but the tries-counter already updated (i.e + * ssh_ptl_tx_next() removed the packet from the queue and updated the + * counter, but re-transmission for the last try has not actually + * started yet). + */ + + spin_lock(&ptl->pending.lock); + + /* Re-queue all pending packets. */ + list_for_each_entry(p, &ptl->pending.head, pending_node) { + /* + * Re-submission fails if the packet is out of tries, has been + * locked, is already queued, or the layer is being shut down. + * No need to re-schedule tx-thread in those cases. + */ + if (!__ssh_ptl_resubmit(p)) + resub = true; + } + + spin_unlock(&ptl->pending.lock); + + if (resub) + ssh_ptl_tx_wakeup_packet(ptl); +} + +/** + * ssh_ptl_cancel() - Cancel a packet. + * @p: The packet to cancel. + * + * Cancels a packet. There are no guarantees on when completion and release + * callbacks will be called. This may occur during execution of this function + * or may occur at any point later. + * + * Note that it is not guaranteed that the packet will actually be canceled if + * the packet is concurrently completed by another process. The only guarantee + * of this function is that the packet will be completed (with success, + * failure, or cancellation) and released from the transport layer in a + * reasonable time-frame. + * + * May be called before the packet has been submitted, in which case any later + * packet submission fails. + */ +void ssh_ptl_cancel(struct ssh_packet *p) +{ + if (test_and_set_bit(SSH_PACKET_SF_CANCELED_BIT, &p->state)) + return; + + /* + * Lock packet and commit with memory barrier. If this packet has + * already been locked, it's going to be removed and completed by + * another party, which should have precedence. + */ + if (test_and_set_bit(SSH_PACKET_SF_LOCKED_BIT, &p->state)) + return; + + /* + * By marking the packet as locked and employing the implicit memory + * barrier of test_and_set_bit, we have guaranteed that, at this point, + * the packet cannot be added to the queue any more. + * + * In case the packet has never been submitted, packet->ptl is NULL. If + * the packet is currently being submitted, packet->ptl may be NULL or + * non-NULL. Due marking the packet as locked above and committing with + * the memory barrier, we have guaranteed that, if packet->ptl is NULL, + * the packet will never be added to the queue. If packet->ptl is + * non-NULL, we don't have any guarantees. + */ + + if (READ_ONCE(p->ptl)) { + ssh_ptl_remove_and_complete(p, -ECANCELED); + + if (atomic_read(&p->ptl->pending.count) < SSH_PTL_MAX_PENDING) + ssh_ptl_tx_wakeup_packet(p->ptl); + + } else if (!test_and_set_bit(SSH_PACKET_SF_COMPLETED_BIT, &p->state)) { + __ssh_ptl_complete(p, -ECANCELED); + } +} + +/* Must be called with pending lock held */ +static ktime_t ssh_packet_get_expiration(struct ssh_packet *p, ktime_t timeout) +{ + lockdep_assert_held(&p->ptl->pending.lock); + + if (p->timestamp != KTIME_MAX) + return ktime_add(p->timestamp, timeout); + else + return KTIME_MAX; +} + +static void ssh_ptl_timeout_reap(struct work_struct *work) +{ + struct ssh_ptl *ptl = to_ssh_ptl(work, rtx_timeout.reaper.work); + struct ssh_packet *p, *n; + LIST_HEAD(claimed); + ktime_t now = ktime_get_coarse_boottime(); + ktime_t timeout = ptl->rtx_timeout.timeout; + ktime_t next = KTIME_MAX; + bool resub = false; + int status; + + /* + * Mark reaper as "not pending". This is done before checking any + * packets to avoid lost-update type problems. + */ + spin_lock(&ptl->rtx_timeout.lock); + ptl->rtx_timeout.expires = KTIME_MAX; + spin_unlock(&ptl->rtx_timeout.lock); + + spin_lock(&ptl->pending.lock); + + list_for_each_entry_safe(p, n, &ptl->pending.head, pending_node) { + ktime_t expires = ssh_packet_get_expiration(p, timeout); + + /* + * Check if the timeout hasn't expired yet. Find out next + * expiration date to be handled after this run. + */ + if (ktime_after(expires, now)) { + next = ktime_before(expires, next) ? expires : next; + continue; + } + + status = __ssh_ptl_resubmit(p); + + /* + * Re-submission fails if the packet is out of tries, has been + * locked, is already queued, or the layer is being shut down. + * No need to re-schedule tx-thread in those cases. + */ + if (!status) + resub = true; + + /* Go to next packet if this packet is not out of tries. */ + if (status != -ECANCELED) + continue; + + /* No more tries left: Cancel the packet. */ + + /* + * If someone else has locked the packet already, don't use it + * and let the other party complete it. + */ + if (test_and_set_bit(SSH_PACKET_SF_LOCKED_BIT, &p->state)) + continue; + + /* + * We have now marked the packet as locked. Thus it cannot be + * added to the pending list again after we've removed it here. + * We can therefore re-use the pending_node of this packet + * temporarily. + */ + + clear_bit(SSH_PACKET_SF_PENDING_BIT, &p->state); + + atomic_dec(&ptl->pending.count); + list_del(&p->pending_node); + + list_add_tail(&p->pending_node, &claimed); + } + + spin_unlock(&ptl->pending.lock); + + /* Cancel and complete the packet. */ + list_for_each_entry_safe(p, n, &claimed, pending_node) { + if (!test_and_set_bit(SSH_PACKET_SF_COMPLETED_BIT, &p->state)) { + ssh_ptl_queue_remove(p); + __ssh_ptl_complete(p, -ETIMEDOUT); + } + + /* + * Drop the reference we've obtained by removing it from + * the pending set. + */ + list_del(&p->pending_node); + ssh_packet_put(p); + } + + /* Ensure that reaper doesn't run again immediately. */ + next = max(next, ktime_add(now, SSH_PTL_PACKET_TIMEOUT_RESOLUTION)); + if (next != KTIME_MAX) + ssh_ptl_timeout_reaper_mod(ptl, now, next); + + if (resub) + ssh_ptl_tx_wakeup_packet(ptl); +} + +static bool ssh_ptl_rx_retransmit_check(struct ssh_ptl *ptl, u8 seq) +{ + int i; + + /* + * Check if SEQ has been seen recently (i.e. packet was + * re-transmitted and we should ignore it). + */ + for (i = 0; i < ARRAY_SIZE(ptl->rx.blocked.seqs); i++) { + if (likely(ptl->rx.blocked.seqs[i] != seq)) + continue; + + ptl_dbg(ptl, "ptl: ignoring repeated data packet\n"); + return true; + } + + /* Update list of blocked sequence IDs. */ + ptl->rx.blocked.seqs[ptl->rx.blocked.offset] = seq; + ptl->rx.blocked.offset = (ptl->rx.blocked.offset + 1) + % ARRAY_SIZE(ptl->rx.blocked.seqs); + + return false; +} + +static void ssh_ptl_rx_dataframe(struct ssh_ptl *ptl, + const struct ssh_frame *frame, + const struct ssam_span *payload) +{ + if (ssh_ptl_rx_retransmit_check(ptl, frame->seq)) + return; + + ptl->ops.data_received(ptl, payload); +} + +static void ssh_ptl_send_ack(struct ssh_ptl *ptl, u8 seq) +{ + struct ssh_packet *packet; + struct ssam_span buf; + struct msgbuf msgb; + int status; + + status = ssh_ctrl_packet_alloc(&packet, &buf, GFP_KERNEL); + if (status) { + ptl_err(ptl, "ptl: failed to allocate ACK packet\n"); + return; + } + + ssh_packet_init(packet, 0, SSH_PACKET_PRIORITY(ACK, 0), + &ssh_ptl_ctrl_packet_ops); + + msgb_init(&msgb, buf.ptr, buf.len); + msgb_push_ack(&msgb, seq); + ssh_packet_set_data(packet, msgb.begin, msgb_bytes_used(&msgb)); + + ssh_ptl_submit(ptl, packet); + ssh_packet_put(packet); +} + +static void ssh_ptl_send_nak(struct ssh_ptl *ptl) +{ + struct ssh_packet *packet; + struct ssam_span buf; + struct msgbuf msgb; + int status; + + status = ssh_ctrl_packet_alloc(&packet, &buf, GFP_KERNEL); + if (status) { + ptl_err(ptl, "ptl: failed to allocate NAK packet\n"); + return; + } + + ssh_packet_init(packet, 0, SSH_PACKET_PRIORITY(NAK, 0), + &ssh_ptl_ctrl_packet_ops); + + msgb_init(&msgb, buf.ptr, buf.len); + msgb_push_nak(&msgb); + ssh_packet_set_data(packet, msgb.begin, msgb_bytes_used(&msgb)); + + ssh_ptl_submit(ptl, packet); + ssh_packet_put(packet); +} + +static size_t ssh_ptl_rx_eval(struct ssh_ptl *ptl, struct ssam_span *source) +{ + struct ssh_frame *frame; + struct ssam_span payload; + struct ssam_span aligned; + bool syn_found; + int status; + + /* Find SYN. */ + syn_found = sshp_find_syn(source, &aligned); + + if (unlikely(aligned.ptr - source->ptr) > 0) { + ptl_warn(ptl, "rx: parser: invalid start of frame, skipping\n"); + + /* + * Notes: + * - This might send multiple NAKs in case the communication + * starts with an invalid SYN and is broken down into multiple + * pieces. This should generally be handled fine, we just + * might receive duplicate data in this case, which is + * detected when handling data frames. + * - This path will also be executed on invalid CRCs: When an + * invalid CRC is encountered, the code below will skip data + * until directly after the SYN. This causes the search for + * the next SYN, which is generally not placed directly after + * the last one. + * + * Open question: Should we send this in case of invalid + * payload CRCs if the frame-type is non-sequential (current + * implementation) or should we drop that frame without + * telling the EC? + */ + ssh_ptl_send_nak(ptl); + } + + if (unlikely(!syn_found)) + return aligned.ptr - source->ptr; + + /* Parse and validate frame. */ + status = sshp_parse_frame(&ptl->serdev->dev, &aligned, &frame, &payload, + SSH_PTL_RX_BUF_LEN); + if (status) /* Invalid frame: skip to next SYN. */ + return aligned.ptr - source->ptr + sizeof(u16); + if (!frame) /* Not enough data. */ + return aligned.ptr - source->ptr; + + switch (frame->type) { + case SSH_FRAME_TYPE_ACK: + ssh_ptl_acknowledge(ptl, frame->seq); + break; + + case SSH_FRAME_TYPE_NAK: + ssh_ptl_resubmit_pending(ptl); + break; + + case SSH_FRAME_TYPE_DATA_SEQ: + ssh_ptl_send_ack(ptl, frame->seq); + fallthrough; + + case SSH_FRAME_TYPE_DATA_NSQ: + ssh_ptl_rx_dataframe(ptl, frame, &payload); + break; + + default: + ptl_warn(ptl, "ptl: received frame with unknown type %#04x\n", + frame->type); + break; + } + + return aligned.ptr - source->ptr + SSH_MESSAGE_LENGTH(frame->len); +} + +static int ssh_ptl_rx_threadfn(void *data) +{ + struct ssh_ptl *ptl = data; + + while (true) { + struct ssam_span span; + size_t offs = 0; + size_t n; + + wait_event_interruptible(ptl->rx.wq, + !kfifo_is_empty(&ptl->rx.fifo) || + kthread_should_stop()); + if (kthread_should_stop()) + break; + + /* Copy from fifo to evaluation buffer. */ + n = sshp_buf_read_from_fifo(&ptl->rx.buf, &ptl->rx.fifo); + + ptl_dbg(ptl, "rx: received data (size: %zu)\n", n); + print_hex_dump_debug("rx: ", DUMP_PREFIX_OFFSET, 16, 1, + ptl->rx.buf.ptr + ptl->rx.buf.len - n, + n, false); + + /* Parse until we need more bytes or buffer is empty. */ + while (offs < ptl->rx.buf.len) { + sshp_buf_span_from(&ptl->rx.buf, offs, &span); + n = ssh_ptl_rx_eval(ptl, &span); + if (n == 0) + break; /* Need more bytes. */ + + offs += n; + } + + /* Throw away the evaluated parts. */ + sshp_buf_drop(&ptl->rx.buf, offs); + } + + return 0; +} + +static void ssh_ptl_rx_wakeup(struct ssh_ptl *ptl) +{ + wake_up(&ptl->rx.wq); +} + +/** + * ssh_ptl_rx_start() - Start packet transport layer receiver thread. + * @ptl: The packet transport layer. + * + * Return: Returns zero on success, a negative error code on failure. + */ +int ssh_ptl_rx_start(struct ssh_ptl *ptl) +{ + if (ptl->rx.thread) + return 0; + + ptl->rx.thread = kthread_run(ssh_ptl_rx_threadfn, ptl, + "ssam_serial_hub-rx"); + if (IS_ERR(ptl->rx.thread)) + return PTR_ERR(ptl->rx.thread); + + return 0; +} + +/** + * ssh_ptl_rx_stop() - Stop packet transport layer receiver thread. + * @ptl: The packet transport layer. + * + * Return: Returns zero on success, a negative error code on failure. + */ +int ssh_ptl_rx_stop(struct ssh_ptl *ptl) +{ + int status = 0; + + if (ptl->rx.thread) { + status = kthread_stop(ptl->rx.thread); + ptl->rx.thread = NULL; + } + + return status; +} + +/** + * ssh_ptl_rx_rcvbuf() - Push data from lower-layer transport to the packet + * layer. + * @ptl: The packet transport layer. + * @buf: Pointer to the data to push to the layer. + * @n: Size of the data to push to the layer, in bytes. + * + * Pushes data from a lower-layer transport to the receiver fifo buffer of the + * packet layer and notifies the receiver thread. Calls to this function are + * ignored once the packet layer has been shut down. + * + * Return: Returns the number of bytes transferred (positive or zero) on + * success. Returns %-ESHUTDOWN if the packet layer has been shut down. + */ +int ssh_ptl_rx_rcvbuf(struct ssh_ptl *ptl, const u8 *buf, size_t n) +{ + int used; + + if (test_bit(SSH_PTL_SF_SHUTDOWN_BIT, &ptl->state)) + return -ESHUTDOWN; + + used = kfifo_in(&ptl->rx.fifo, buf, n); + if (used) + ssh_ptl_rx_wakeup(ptl); + + return used; +} + +/** + * ssh_ptl_shutdown() - Shut down the packet transport layer. + * @ptl: The packet transport layer. + * + * Shuts down the packet transport layer, removing and canceling all queued + * and pending packets. Packets canceled by this operation will be completed + * with %-ESHUTDOWN as status. Receiver and transmitter threads will be + * stopped. + * + * As a result of this function, the transport layer will be marked as shut + * down. Submission of packets after the transport layer has been shut down + * will fail with %-ESHUTDOWN. + */ +void ssh_ptl_shutdown(struct ssh_ptl *ptl) +{ + LIST_HEAD(complete_q); + LIST_HEAD(complete_p); + struct ssh_packet *p, *n; + int status; + + /* Ensure that no new packets (including ACK/NAK) can be submitted. */ + set_bit(SSH_PTL_SF_SHUTDOWN_BIT, &ptl->state); + /* + * Ensure that the layer gets marked as shut-down before actually + * stopping it. In combination with the check in ssh_ptl_queue_push(), + * this guarantees that no new packets can be added and all already + * queued packets are properly canceled. In combination with the check + * in ssh_ptl_rx_rcvbuf(), this guarantees that received data is + * properly cut off. + */ + smp_mb__after_atomic(); + + status = ssh_ptl_rx_stop(ptl); + if (status) + ptl_err(ptl, "ptl: failed to stop receiver thread\n"); + + status = ssh_ptl_tx_stop(ptl); + if (status) + ptl_err(ptl, "ptl: failed to stop transmitter thread\n"); + + cancel_delayed_work_sync(&ptl->rtx_timeout.reaper); + + /* + * At this point, all threads have been stopped. This means that the + * only references to packets from inside the system are in the queue + * and pending set. + * + * Note: We still need locks here because someone could still be + * canceling packets. + * + * Note 2: We can re-use queue_node (or pending_node) if we mark the + * packet as locked an then remove it from the queue (or pending set + * respectively). Marking the packet as locked avoids re-queuing + * (which should already be prevented by having stopped the treads...) + * and not setting QUEUED_BIT (or PENDING_BIT) prevents removal from a + * new list via other threads (e.g. cancellation). + * + * Note 3: There may be overlap between complete_p and complete_q. + * This is handled via test_and_set_bit() on the "completed" flag + * (also handles cancellation). + */ + + /* Mark queued packets as locked and move them to complete_q. */ + spin_lock(&ptl->queue.lock); + list_for_each_entry_safe(p, n, &ptl->queue.head, queue_node) { + set_bit(SSH_PACKET_SF_LOCKED_BIT, &p->state); + /* Ensure that state does not get zero. */ + smp_mb__before_atomic(); + clear_bit(SSH_PACKET_SF_QUEUED_BIT, &p->state); + + list_del(&p->queue_node); + list_add_tail(&p->queue_node, &complete_q); + } + spin_unlock(&ptl->queue.lock); + + /* Mark pending packets as locked and move them to complete_p. */ + spin_lock(&ptl->pending.lock); + list_for_each_entry_safe(p, n, &ptl->pending.head, pending_node) { + set_bit(SSH_PACKET_SF_LOCKED_BIT, &p->state); + /* Ensure that state does not get zero. */ + smp_mb__before_atomic(); + clear_bit(SSH_PACKET_SF_PENDING_BIT, &p->state); + + list_del(&p->pending_node); + list_add_tail(&p->pending_node, &complete_q); + } + atomic_set(&ptl->pending.count, 0); + spin_unlock(&ptl->pending.lock); + + /* Complete and drop packets on complete_q. */ + list_for_each_entry(p, &complete_q, queue_node) { + if (!test_and_set_bit(SSH_PACKET_SF_COMPLETED_BIT, &p->state)) + __ssh_ptl_complete(p, -ESHUTDOWN); + + ssh_packet_put(p); + } + + /* Complete and drop packets on complete_p. */ + list_for_each_entry(p, &complete_p, pending_node) { + if (!test_and_set_bit(SSH_PACKET_SF_COMPLETED_BIT, &p->state)) + __ssh_ptl_complete(p, -ESHUTDOWN); + + ssh_packet_put(p); + } + + /* + * At this point we have guaranteed that the system doesn't reference + * any packets any more. + */ +} + +/** + * ssh_ptl_init() - Initialize packet transport layer. + * @ptl: The packet transport layer to initialize. + * @serdev: The underlying serial device, i.e. the lower-level transport. + * @ops: Packet layer operations. + * + * Initializes the given packet transport layer. Transmitter and receiver + * threads must be started separately via ssh_ptl_tx_start() and + * ssh_ptl_rx_start(), after the packet-layer has been initialized and the + * lower-level transport layer has been set up. + * + * Return: Returns zero on success and a nonzero error code on failure. + */ +int ssh_ptl_init(struct ssh_ptl *ptl, struct serdev_device *serdev, + struct ssh_ptl_ops *ops) +{ + int i, status; + + ptl->serdev = serdev; + ptl->state = 0; + + spin_lock_init(&ptl->queue.lock); + INIT_LIST_HEAD(&ptl->queue.head); + + spin_lock_init(&ptl->pending.lock); + INIT_LIST_HEAD(&ptl->pending.head); + atomic_set_release(&ptl->pending.count, 0); + + ptl->tx.thread = NULL; + atomic_set(&ptl->tx.running, 0); + init_completion(&ptl->tx.thread_cplt_pkt); + init_completion(&ptl->tx.thread_cplt_tx); + init_waitqueue_head(&ptl->tx.packet_wq); + + ptl->rx.thread = NULL; + init_waitqueue_head(&ptl->rx.wq); + + spin_lock_init(&ptl->rtx_timeout.lock); + ptl->rtx_timeout.timeout = SSH_PTL_PACKET_TIMEOUT; + ptl->rtx_timeout.expires = KTIME_MAX; + INIT_DELAYED_WORK(&ptl->rtx_timeout.reaper, ssh_ptl_timeout_reap); + + ptl->ops = *ops; + + /* Initialize list of recent/blocked SEQs with invalid sequence IDs. */ + for (i = 0; i < ARRAY_SIZE(ptl->rx.blocked.seqs); i++) + ptl->rx.blocked.seqs[i] = U16_MAX; + ptl->rx.blocked.offset = 0; + + status = kfifo_alloc(&ptl->rx.fifo, SSH_PTL_RX_FIFO_LEN, GFP_KERNEL); + if (status) + return status; + + status = sshp_buf_alloc(&ptl->rx.buf, SSH_PTL_RX_BUF_LEN, GFP_KERNEL); + if (status) + kfifo_free(&ptl->rx.fifo); + + return status; +} + +/** + * ssh_ptl_destroy() - Deinitialize packet transport layer. + * @ptl: The packet transport layer to deinitialize. + * + * Deinitializes the given packet transport layer and frees resources + * associated with it. If receiver and/or transmitter threads have been + * started, the layer must first be shut down via ssh_ptl_shutdown() before + * this function can be called. + */ +void ssh_ptl_destroy(struct ssh_ptl *ptl) +{ + kfifo_free(&ptl->rx.fifo); + sshp_buf_free(&ptl->rx.buf); +} diff --git a/drivers/platform/surface/aggregator/ssh_packet_layer.h b/drivers/platform/surface/aggregator/ssh_packet_layer.h new file mode 100644 index 000000000000..058f111292ca --- /dev/null +++ b/drivers/platform/surface/aggregator/ssh_packet_layer.h @@ -0,0 +1,187 @@ +/* SPDX-License-Identifier: GPL-2.0+ */ +/* + * SSH packet transport layer. + * + * Copyright (C) 2019-2020 Maximilian Luz + */ + +#ifndef _SURFACE_AGGREGATOR_SSH_PACKET_LAYER_H +#define _SURFACE_AGGREGATOR_SSH_PACKET_LAYER_H + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include "ssh_parser.h" + +/** + * enum ssh_ptl_state_flags - State-flags for &struct ssh_ptl. + * + * @SSH_PTL_SF_SHUTDOWN_BIT: + * Indicates that the packet transport layer has been shut down or is + * being shut down and should not accept any new packets/data. + */ +enum ssh_ptl_state_flags { + SSH_PTL_SF_SHUTDOWN_BIT, +}; + +/** + * struct ssh_ptl_ops - Callback operations for packet transport layer. + * @data_received: Function called when a data-packet has been received. Both, + * the packet layer on which the packet has been received and + * the packet's payload data are provided to this function. + */ +struct ssh_ptl_ops { + void (*data_received)(struct ssh_ptl *p, const struct ssam_span *data); +}; + +/** + * struct ssh_ptl - SSH packet transport layer. + * @serdev: Serial device providing the underlying data transport. + * @state: State(-flags) of the transport layer. + * @queue: Packet submission queue. + * @queue.lock: Lock for modifying the packet submission queue. + * @queue.head: List-head of the packet submission queue. + * @pending: Set/list of pending packets. + * @pending.lock: Lock for modifying the pending set. + * @pending.head: List-head of the pending set/list. + * @pending.count: Number of currently pending packets. + * @tx: Transmitter subsystem. + * @tx.running: Flag indicating (desired) transmitter thread state. + * @tx.thread: Transmitter thread. + * @tx.thread_cplt_tx: Completion for transmitter thread waiting on transfer. + * @tx.thread_cplt_pkt: Completion for transmitter thread waiting on packets. + * @tx.packet_wq: Waitqueue-head for packet transmit completion. + * @rx: Receiver subsystem. + * @rx.thread: Receiver thread. + * @rx.wq: Waitqueue-head for receiver thread. + * @rx.fifo: Buffer for receiving data/pushing data to receiver thread. + * @rx.buf: Buffer for evaluating data on receiver thread. + * @rx.blocked: List of recent/blocked sequence IDs to detect retransmission. + * @rx.blocked.seqs: Array of blocked sequence IDs. + * @rx.blocked.offset: Offset indicating where a new ID should be inserted. + * @rtx_timeout: Retransmission timeout subsystem. + * @rtx_timeout.lock: Lock for modifying the retransmission timeout reaper. + * @rtx_timeout.timeout: Timeout interval for retransmission. + * @rtx_timeout.expires: Time specifying when the reaper work is next scheduled. + * @rtx_timeout.reaper: Work performing timeout checks and subsequent actions. + * @ops: Packet layer operations. + */ +struct ssh_ptl { + struct serdev_device *serdev; + unsigned long state; + + struct { + spinlock_t lock; + struct list_head head; + } queue; + + struct { + spinlock_t lock; + struct list_head head; + atomic_t count; + } pending; + + struct { + atomic_t running; + struct task_struct *thread; + struct completion thread_cplt_tx; + struct completion thread_cplt_pkt; + struct wait_queue_head packet_wq; + } tx; + + struct { + struct task_struct *thread; + struct wait_queue_head wq; + struct kfifo fifo; + struct sshp_buf buf; + + struct { + u16 seqs[8]; + u16 offset; + } blocked; + } rx; + + struct { + spinlock_t lock; + ktime_t timeout; + ktime_t expires; + struct delayed_work reaper; + } rtx_timeout; + + struct ssh_ptl_ops ops; +}; + +#define __ssam_prcond(func, p, fmt, ...) \ + do { \ + typeof(p) __p = (p); \ + \ + if (__p) \ + func(__p, fmt, ##__VA_ARGS__); \ + } while (0) + +#define ptl_dbg(p, fmt, ...) dev_dbg(&(p)->serdev->dev, fmt, ##__VA_ARGS__) +#define ptl_info(p, fmt, ...) dev_info(&(p)->serdev->dev, fmt, ##__VA_ARGS__) +#define ptl_warn(p, fmt, ...) dev_warn(&(p)->serdev->dev, fmt, ##__VA_ARGS__) +#define ptl_err(p, fmt, ...) dev_err(&(p)->serdev->dev, fmt, ##__VA_ARGS__) +#define ptl_dbg_cond(p, fmt, ...) __ssam_prcond(ptl_dbg, p, fmt, ##__VA_ARGS__) + +#define to_ssh_ptl(ptr, member) \ + container_of(ptr, struct ssh_ptl, member) + +int ssh_ptl_init(struct ssh_ptl *ptl, struct serdev_device *serdev, + struct ssh_ptl_ops *ops); + +void ssh_ptl_destroy(struct ssh_ptl *ptl); + +/** + * ssh_ptl_get_device() - Get device associated with packet transport layer. + * @ptl: The packet transport layer. + * + * Return: Returns the device on which the given packet transport layer builds + * upon. + */ +static inline struct device *ssh_ptl_get_device(struct ssh_ptl *ptl) +{ + return ptl->serdev ? &ptl->serdev->dev : NULL; +} + +int ssh_ptl_tx_start(struct ssh_ptl *ptl); +int ssh_ptl_tx_stop(struct ssh_ptl *ptl); +int ssh_ptl_rx_start(struct ssh_ptl *ptl); +int ssh_ptl_rx_stop(struct ssh_ptl *ptl); +void ssh_ptl_shutdown(struct ssh_ptl *ptl); + +int ssh_ptl_submit(struct ssh_ptl *ptl, struct ssh_packet *p); +void ssh_ptl_cancel(struct ssh_packet *p); + +int ssh_ptl_rx_rcvbuf(struct ssh_ptl *ptl, const u8 *buf, size_t n); + +/** + * ssh_ptl_tx_wakeup_transfer() - Wake up packet transmitter thread for + * transfer. + * @ptl: The packet transport layer. + * + * Wakes up the packet transmitter thread, notifying it that the underlying + * transport has more space for data to be transmitted. If the packet + * transport layer has been shut down, calls to this function will be ignored. + */ +static inline void ssh_ptl_tx_wakeup_transfer(struct ssh_ptl *ptl) +{ + if (test_bit(SSH_PTL_SF_SHUTDOWN_BIT, &ptl->state)) + return; + + complete(&ptl->tx.thread_cplt_tx); +} + +void ssh_packet_init(struct ssh_packet *packet, unsigned long type, + u8 priority, const struct ssh_packet_ops *ops); + +#endif /* _SURFACE_AGGREGATOR_SSH_PACKET_LAYER_H */ diff --git a/drivers/platform/surface/aggregator/ssh_parser.c b/drivers/platform/surface/aggregator/ssh_parser.c new file mode 100644 index 000000000000..e2dead8de94a --- /dev/null +++ b/drivers/platform/surface/aggregator/ssh_parser.c @@ -0,0 +1,228 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * SSH message parser. + * + * Copyright (C) 2019-2020 Maximilian Luz + */ + +#include +#include +#include +#include + +#include +#include "ssh_parser.h" + +/** + * sshp_validate_crc() - Validate a CRC in raw message data. + * @src: The span of data over which the CRC should be computed. + * @crc: The pointer to the expected u16 CRC value. + * + * Computes the CRC of the provided data span (@src), compares it to the CRC + * stored at the given address (@crc), and returns the result of this + * comparison, i.e. %true if equal. This function is intended to run on raw + * input/message data. + * + * Return: Returns %true if the computed CRC matches the stored CRC, %false + * otherwise. + */ +static bool sshp_validate_crc(const struct ssam_span *src, const u8 *crc) +{ + u16 actual = ssh_crc(src->ptr, src->len); + u16 expected = get_unaligned_le16(crc); + + return actual == expected; +} + +/** + * sshp_starts_with_syn() - Check if the given data starts with SSH SYN bytes. + * @src: The data span to check the start of. + */ +static bool sshp_starts_with_syn(const struct ssam_span *src) +{ + return src->len >= 2 && get_unaligned_le16(src->ptr) == SSH_MSG_SYN; +} + +/** + * sshp_find_syn() - Find SSH SYN bytes in the given data span. + * @src: The data span to search in. + * @rem: The span (output) indicating the remaining data, starting with SSH + * SYN bytes, if found. + * + * Search for SSH SYN bytes in the given source span. If found, set the @rem + * span to the remaining data, starting with the first SYN bytes and capped by + * the source span length, and return %true. This function does not copy any + * data, but rather only sets pointers to the respective start addresses and + * length values. + * + * If no SSH SYN bytes could be found, set the @rem span to the zero-length + * span at the end of the source span and return %false. + * + * If partial SSH SYN bytes could be found at the end of the source span, set + * the @rem span to cover these partial SYN bytes, capped by the end of the + * source span, and return %false. This function should then be re-run once + * more data is available. + * + * Return: Returns %true if a complete SSH SYN sequence could be found, + * %false otherwise. + */ +bool sshp_find_syn(const struct ssam_span *src, struct ssam_span *rem) +{ + size_t i; + + for (i = 0; i < src->len - 1; i++) { + if (likely(get_unaligned_le16(src->ptr + i) == SSH_MSG_SYN)) { + rem->ptr = src->ptr + i; + rem->len = src->len - i; + return true; + } + } + + if (unlikely(src->ptr[src->len - 1] == (SSH_MSG_SYN & 0xff))) { + rem->ptr = src->ptr + src->len - 1; + rem->len = 1; + return false; + } + + rem->ptr = src->ptr + src->len; + rem->len = 0; + return false; +} + +/** + * sshp_parse_frame() - Parse SSH frame. + * @dev: The device used for logging. + * @source: The source to parse from. + * @frame: The parsed frame (output). + * @payload: The parsed payload (output). + * @maxlen: The maximum supported message length. + * + * Parses and validates a SSH frame, including its payload, from the given + * source. Sets the provided @frame pointer to the start of the frame and + * writes the limits of the frame payload to the provided @payload span + * pointer. + * + * This function does not copy any data, but rather only validates the message + * data and sets pointers (and length values) to indicate the respective parts. + * + * If no complete SSH frame could be found, the frame pointer will be set to + * the %NULL pointer and the payload span will be set to the null span (start + * pointer %NULL, size zero). + * + * Return: Returns zero on success or if the frame is incomplete, %-ENOMSG if + * the start of the message is invalid, %-EBADMSG if any (frame-header or + * payload) CRC is invalid, or %-EMSGSIZE if the SSH message is bigger than + * the maximum message length specified in the @maxlen parameter. + */ +int sshp_parse_frame(const struct device *dev, const struct ssam_span *source, + struct ssh_frame **frame, struct ssam_span *payload, + size_t maxlen) +{ + struct ssam_span sf; + struct ssam_span sp; + + /* Initialize output. */ + *frame = NULL; + payload->ptr = NULL; + payload->len = 0; + + if (!sshp_starts_with_syn(source)) { + dev_warn(dev, "rx: parser: invalid start of frame\n"); + return -ENOMSG; + } + + /* Check for minimum packet length. */ + if (unlikely(source->len < SSH_MESSAGE_LENGTH(0))) { + dev_dbg(dev, "rx: parser: not enough data for frame\n"); + return 0; + } + + /* Pin down frame. */ + sf.ptr = source->ptr + sizeof(u16); + sf.len = sizeof(struct ssh_frame); + + /* Validate frame CRC. */ + if (unlikely(!sshp_validate_crc(&sf, sf.ptr + sf.len))) { + dev_warn(dev, "rx: parser: invalid frame CRC\n"); + return -EBADMSG; + } + + /* Ensure packet does not exceed maximum length. */ + sp.len = get_unaligned_le16(&((struct ssh_frame *)sf.ptr)->len); + if (unlikely(SSH_MESSAGE_LENGTH(sp.len) > maxlen)) { + dev_warn(dev, "rx: parser: frame too large: %llu bytes\n", + SSH_MESSAGE_LENGTH(sp.len)); + return -EMSGSIZE; + } + + /* Pin down payload. */ + sp.ptr = sf.ptr + sf.len + sizeof(u16); + + /* Check for frame + payload length. */ + if (source->len < SSH_MESSAGE_LENGTH(sp.len)) { + dev_dbg(dev, "rx: parser: not enough data for payload\n"); + return 0; + } + + /* Validate payload CRC. */ + if (unlikely(!sshp_validate_crc(&sp, sp.ptr + sp.len))) { + dev_warn(dev, "rx: parser: invalid payload CRC\n"); + return -EBADMSG; + } + + *frame = (struct ssh_frame *)sf.ptr; + *payload = sp; + + dev_dbg(dev, "rx: parser: valid frame found (type: %#04x, len: %u)\n", + (*frame)->type, (*frame)->len); + + return 0; +} + +/** + * sshp_parse_command() - Parse SSH command frame payload. + * @dev: The device used for logging. + * @source: The source to parse from. + * @command: The parsed command (output). + * @command_data: The parsed command data/payload (output). + * + * Parses and validates a SSH command frame payload. Sets the @command pointer + * to the command header and the @command_data span to the command data (i.e. + * payload of the command). This will result in a zero-length span if the + * command does not have any associated data/payload. This function does not + * check the frame-payload-type field, which should be checked by the caller + * before calling this function. + * + * The @source parameter should be the complete frame payload, e.g. returned + * by the sshp_parse_frame() command. + * + * This function does not copy any data, but rather only validates the frame + * payload data and sets pointers (and length values) to indicate the + * respective parts. + * + * Return: Returns zero on success or %-ENOMSG if @source does not represent a + * valid command-type frame payload, i.e. is too short. + */ +int sshp_parse_command(const struct device *dev, const struct ssam_span *source, + struct ssh_command **command, + struct ssam_span *command_data) +{ + /* Check for minimum length. */ + if (unlikely(source->len < sizeof(struct ssh_command))) { + *command = NULL; + command_data->ptr = NULL; + command_data->len = 0; + + dev_err(dev, "rx: parser: command payload is too short\n"); + return -ENOMSG; + } + + *command = (struct ssh_command *)source->ptr; + command_data->ptr = source->ptr + sizeof(struct ssh_command); + command_data->len = source->len - sizeof(struct ssh_command); + + dev_dbg(dev, "rx: parser: valid command found (tc: %#04x, cid: %#04x)\n", + (*command)->tc, (*command)->cid); + + return 0; +} diff --git a/drivers/platform/surface/aggregator/ssh_parser.h b/drivers/platform/surface/aggregator/ssh_parser.h new file mode 100644 index 000000000000..63c38d350988 --- /dev/null +++ b/drivers/platform/surface/aggregator/ssh_parser.h @@ -0,0 +1,154 @@ +/* SPDX-License-Identifier: GPL-2.0+ */ +/* + * SSH message parser. + * + * Copyright (C) 2019-2020 Maximilian Luz + */ + +#ifndef _SURFACE_AGGREGATOR_SSH_PARSER_H +#define _SURFACE_AGGREGATOR_SSH_PARSER_H + +#include +#include +#include +#include + +#include + +/** + * struct sshp_buf - Parser buffer for SSH messages. + * @ptr: Pointer to the beginning of the buffer. + * @len: Number of bytes used in the buffer. + * @cap: Maximum capacity of the buffer. + */ +struct sshp_buf { + u8 *ptr; + size_t len; + size_t cap; +}; + +/** + * sshp_buf_init() - Initialize a SSH parser buffer. + * @buf: The buffer to initialize. + * @ptr: The memory backing the buffer. + * @cap: The length of the memory backing the buffer, i.e. its capacity. + * + * Initializes the buffer with the given memory as backing and set its used + * length to zero. + */ +static inline void sshp_buf_init(struct sshp_buf *buf, u8 *ptr, size_t cap) +{ + buf->ptr = ptr; + buf->len = 0; + buf->cap = cap; +} + +/** + * sshp_buf_alloc() - Allocate and initialize a SSH parser buffer. + * @buf: The buffer to initialize/allocate to. + * @cap: The desired capacity of the buffer. + * @flags: The flags used for allocating the memory. + * + * Allocates @cap bytes and initializes the provided buffer struct with the + * allocated memory. + * + * Return: Returns zero on success and %-ENOMEM if allocation failed. + */ +static inline int sshp_buf_alloc(struct sshp_buf *buf, size_t cap, gfp_t flags) +{ + u8 *ptr; + + ptr = kzalloc(cap, flags); + if (!ptr) + return -ENOMEM; + + sshp_buf_init(buf, ptr, cap); + return 0; +} + +/** + * sshp_buf_free() - Free a SSH parser buffer. + * @buf: The buffer to free. + * + * Frees a SSH parser buffer by freeing the memory backing it and then + * resetting its pointer to %NULL and length and capacity to zero. Intended to + * free a buffer previously allocated with sshp_buf_alloc(). + */ +static inline void sshp_buf_free(struct sshp_buf *buf) +{ + kfree(buf->ptr); + buf->ptr = NULL; + buf->len = 0; + buf->cap = 0; +} + +/** + * sshp_buf_drop() - Drop data from the beginning of the buffer. + * @buf: The buffer to drop data from. + * @n: The number of bytes to drop. + * + * Drops the first @n bytes from the buffer. Re-aligns any remaining data to + * the beginning of the buffer. + */ +static inline void sshp_buf_drop(struct sshp_buf *buf, size_t n) +{ + memmove(buf->ptr, buf->ptr + n, buf->len - n); + buf->len -= n; +} + +/** + * sshp_buf_read_from_fifo() - Transfer data from a fifo to the buffer. + * @buf: The buffer to write the data into. + * @fifo: The fifo to read the data from. + * + * Transfers the data contained in the fifo to the buffer, removing it from + * the fifo. This function will try to transfer as much data as possible, + * limited either by the remaining space in the buffer or by the number of + * bytes available in the fifo. + * + * Return: Returns the number of bytes transferred. + */ +static inline size_t sshp_buf_read_from_fifo(struct sshp_buf *buf, + struct kfifo *fifo) +{ + size_t n; + + n = kfifo_out(fifo, buf->ptr + buf->len, buf->cap - buf->len); + buf->len += n; + + return n; +} + +/** + * sshp_buf_span_from() - Initialize a span from the given buffer and offset. + * @buf: The buffer to create the span from. + * @offset: The offset in the buffer at which the span should start. + * @span: The span to initialize (output). + * + * Initializes the provided span to point to the memory at the given offset in + * the buffer, with the length of the span being capped by the number of bytes + * used in the buffer after the offset (i.e. bytes remaining after the + * offset). + * + * Warning: This function does not validate that @offset is less than or equal + * to the number of bytes used in the buffer or the buffer capacity. This must + * be guaranteed by the caller. + */ +static inline void sshp_buf_span_from(struct sshp_buf *buf, size_t offset, + struct ssam_span *span) +{ + span->ptr = buf->ptr + offset; + span->len = buf->len - offset; +} + +bool sshp_find_syn(const struct ssam_span *src, struct ssam_span *rem); + +int sshp_parse_frame(const struct device *dev, const struct ssam_span *source, + struct ssh_frame **frame, struct ssam_span *payload, + size_t maxlen); + +int sshp_parse_command(const struct device *dev, const struct ssam_span *source, + struct ssh_command **command, + struct ssam_span *command_data); + +#endif /* _SURFACE_AGGREGATOR_SSH_PARSER_h */ diff --git a/drivers/platform/surface/aggregator/ssh_request_layer.c b/drivers/platform/surface/aggregator/ssh_request_layer.c new file mode 100644 index 000000000000..66c839a995f3 --- /dev/null +++ b/drivers/platform/surface/aggregator/ssh_request_layer.c @@ -0,0 +1,1211 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * SSH request transport layer. + * + * Copyright (C) 2019-2020 Maximilian Luz + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include + +#include "ssh_packet_layer.h" +#include "ssh_request_layer.h" + +/* + * SSH_RTL_REQUEST_TIMEOUT - Request timeout. + * + * Timeout as ktime_t delta for request responses. If we have not received a + * response in this time-frame after finishing the underlying packet + * transmission, the request will be completed with %-ETIMEDOUT as status + * code. + */ +#define SSH_RTL_REQUEST_TIMEOUT ms_to_ktime(3000) + +/* + * SSH_RTL_REQUEST_TIMEOUT_RESOLUTION - Request timeout granularity. + * + * Time-resolution for timeouts. Should be larger than one jiffy to avoid + * direct re-scheduling of reaper work_struct. + */ +#define SSH_RTL_REQUEST_TIMEOUT_RESOLUTION ms_to_ktime(max(2000 / HZ, 50)) + +/* + * SSH_RTL_MAX_PENDING - Maximum number of pending requests. + * + * Maximum number of requests concurrently waiting to be completed (i.e. + * waiting for the corresponding packet transmission to finish if they don't + * have a response or waiting for a response if they have one). + */ +#define SSH_RTL_MAX_PENDING 3 + +/* + * SSH_RTL_TX_BATCH - Maximum number of requests processed per work execution. + * Used to prevent livelocking of the workqueue. Value chosen via educated + * guess, may be adjusted. + */ +#define SSH_RTL_TX_BATCH 10 + +static u16 ssh_request_get_rqid(struct ssh_request *rqst) +{ + return get_unaligned_le16(rqst->packet.data.ptr + + SSH_MSGOFFSET_COMMAND(rqid)); +} + +static u32 ssh_request_get_rqid_safe(struct ssh_request *rqst) +{ + if (!rqst->packet.data.ptr) + return U32_MAX; + + return ssh_request_get_rqid(rqst); +} + +static void ssh_rtl_queue_remove(struct ssh_request *rqst) +{ + struct ssh_rtl *rtl = ssh_request_rtl(rqst); + + spin_lock(&rtl->queue.lock); + + if (!test_and_clear_bit(SSH_REQUEST_SF_QUEUED_BIT, &rqst->state)) { + spin_unlock(&rtl->queue.lock); + return; + } + + list_del(&rqst->node); + + spin_unlock(&rtl->queue.lock); + ssh_request_put(rqst); +} + +static bool ssh_rtl_queue_empty(struct ssh_rtl *rtl) +{ + bool empty; + + spin_lock(&rtl->queue.lock); + empty = list_empty(&rtl->queue.head); + spin_unlock(&rtl->queue.lock); + + return empty; +} + +static void ssh_rtl_pending_remove(struct ssh_request *rqst) +{ + struct ssh_rtl *rtl = ssh_request_rtl(rqst); + + spin_lock(&rtl->pending.lock); + + if (!test_and_clear_bit(SSH_REQUEST_SF_PENDING_BIT, &rqst->state)) { + spin_unlock(&rtl->pending.lock); + return; + } + + atomic_dec(&rtl->pending.count); + list_del(&rqst->node); + + spin_unlock(&rtl->pending.lock); + + ssh_request_put(rqst); +} + +static int ssh_rtl_tx_pending_push(struct ssh_request *rqst) +{ + struct ssh_rtl *rtl = ssh_request_rtl(rqst); + + spin_lock(&rtl->pending.lock); + + if (test_bit(SSH_REQUEST_SF_LOCKED_BIT, &rqst->state)) { + spin_unlock(&rtl->pending.lock); + return -EINVAL; + } + + if (test_and_set_bit(SSH_REQUEST_SF_PENDING_BIT, &rqst->state)) { + spin_unlock(&rtl->pending.lock); + return -EALREADY; + } + + atomic_inc(&rtl->pending.count); + list_add_tail(&ssh_request_get(rqst)->node, &rtl->pending.head); + + spin_unlock(&rtl->pending.lock); + return 0; +} + +static void ssh_rtl_complete_with_status(struct ssh_request *rqst, int status) +{ + struct ssh_rtl *rtl = ssh_request_rtl(rqst); + + /* rtl/ptl may not be set if we're canceling before submitting. */ + rtl_dbg_cond(rtl, "rtl: completing request (rqid: %#06x, status: %d)\n", + ssh_request_get_rqid_safe(rqst), status); + + rqst->ops->complete(rqst, NULL, NULL, status); +} + +static void ssh_rtl_complete_with_rsp(struct ssh_request *rqst, + const struct ssh_command *cmd, + const struct ssam_span *data) +{ + struct ssh_rtl *rtl = ssh_request_rtl(rqst); + + rtl_dbg(rtl, "rtl: completing request with response (rqid: %#06x)\n", + ssh_request_get_rqid(rqst)); + + rqst->ops->complete(rqst, cmd, data, 0); +} + +static bool ssh_rtl_tx_can_process(struct ssh_request *rqst) +{ + struct ssh_rtl *rtl = ssh_request_rtl(rqst); + + if (test_bit(SSH_REQUEST_TY_FLUSH_BIT, &rqst->state)) + return !atomic_read(&rtl->pending.count); + + return atomic_read(&rtl->pending.count) < SSH_RTL_MAX_PENDING; +} + +static struct ssh_request *ssh_rtl_tx_next(struct ssh_rtl *rtl) +{ + struct ssh_request *rqst = ERR_PTR(-ENOENT); + struct ssh_request *p, *n; + + spin_lock(&rtl->queue.lock); + + /* Find first non-locked request and remove it. */ + list_for_each_entry_safe(p, n, &rtl->queue.head, node) { + if (unlikely(test_bit(SSH_REQUEST_SF_LOCKED_BIT, &p->state))) + continue; + + if (!ssh_rtl_tx_can_process(p)) { + rqst = ERR_PTR(-EBUSY); + break; + } + + /* Remove from queue and mark as transmitting. */ + set_bit(SSH_REQUEST_SF_TRANSMITTING_BIT, &p->state); + /* Ensure state never gets zero. */ + smp_mb__before_atomic(); + clear_bit(SSH_REQUEST_SF_QUEUED_BIT, &p->state); + + list_del(&p->node); + + rqst = p; + break; + } + + spin_unlock(&rtl->queue.lock); + return rqst; +} + +static int ssh_rtl_tx_try_process_one(struct ssh_rtl *rtl) +{ + struct ssh_request *rqst; + int status; + + /* Get and prepare next request for transmit. */ + rqst = ssh_rtl_tx_next(rtl); + if (IS_ERR(rqst)) + return PTR_ERR(rqst); + + /* Add it to/mark it as pending. */ + status = ssh_rtl_tx_pending_push(rqst); + if (status) { + ssh_request_put(rqst); + return -EAGAIN; + } + + /* Submit packet. */ + status = ssh_ptl_submit(&rtl->ptl, &rqst->packet); + if (status == -ESHUTDOWN) { + /* + * Packet has been refused due to the packet layer shutting + * down. Complete it here. + */ + set_bit(SSH_REQUEST_SF_LOCKED_BIT, &rqst->state); + /* + * Note: A barrier is not required here, as there are only two + * references in the system at this point: The one that we have, + * and the other one that belongs to the pending set. Due to the + * request being marked as "transmitting", our process is the + * only one allowed to remove the pending node and change the + * state. Normally, the task would fall to the packet callback, + * but as this is a path where submission failed, this callback + * will never be executed. + */ + + ssh_rtl_pending_remove(rqst); + ssh_rtl_complete_with_status(rqst, -ESHUTDOWN); + + ssh_request_put(rqst); + return -ESHUTDOWN; + + } else if (status) { + /* + * If submitting the packet failed and the packet layer isn't + * shutting down, the packet has either been submitted/queued + * before (-EALREADY, which cannot happen as we have + * guaranteed that requests cannot be re-submitted), or the + * packet was marked as locked (-EINVAL). To mark the packet + * locked at this stage, the request, and thus the packets + * itself, had to have been canceled. Simply drop the + * reference. Cancellation itself will remove it from the set + * of pending requests. + */ + + WARN_ON(status != -EINVAL); + + ssh_request_put(rqst); + return -EAGAIN; + } + + ssh_request_put(rqst); + return 0; +} + +static bool ssh_rtl_tx_schedule(struct ssh_rtl *rtl) +{ + if (atomic_read(&rtl->pending.count) >= SSH_RTL_MAX_PENDING) + return false; + + if (ssh_rtl_queue_empty(rtl)) + return false; + + return schedule_work(&rtl->tx.work); +} + +static void ssh_rtl_tx_work_fn(struct work_struct *work) +{ + struct ssh_rtl *rtl = to_ssh_rtl(work, tx.work); + unsigned int iterations = SSH_RTL_TX_BATCH; + int status; + + /* + * Try to be nice and not block/live-lock the workqueue: Run a maximum + * of 10 tries, then re-submit if necessary. This should not be + * necessary for normal execution, but guarantee it anyway. + */ + do { + status = ssh_rtl_tx_try_process_one(rtl); + if (status == -ENOENT || status == -EBUSY) + return; /* No more requests to process. */ + + if (status == -ESHUTDOWN) { + /* + * Packet system shutting down. No new packets can be + * transmitted. Return silently, the party initiating + * the shutdown should handle the rest. + */ + return; + } + + WARN_ON(status != 0 && status != -EAGAIN); + } while (--iterations); + + /* Out of tries, reschedule. */ + ssh_rtl_tx_schedule(rtl); +} + +/** + * ssh_rtl_submit() - Submit a request to the transport layer. + * @rtl: The request transport layer. + * @rqst: The request to submit. + * + * Submits a request to the transport layer. A single request may not be + * submitted multiple times without reinitializing it. + * + * Return: Returns zero on success, %-EINVAL if the request type is invalid or + * the request has been canceled prior to submission, %-EALREADY if the + * request has already been submitted, or %-ESHUTDOWN in case the request + * transport layer has been shut down. + */ +int ssh_rtl_submit(struct ssh_rtl *rtl, struct ssh_request *rqst) +{ + /* + * Ensure that requests expecting a response are sequenced. If this + * invariant ever changes, see the comment in ssh_rtl_complete() on what + * is required to be changed in the code. + */ + if (test_bit(SSH_REQUEST_TY_HAS_RESPONSE_BIT, &rqst->state)) + if (!test_bit(SSH_PACKET_TY_SEQUENCED_BIT, &rqst->packet.state)) + return -EINVAL; + + spin_lock(&rtl->queue.lock); + + /* + * Try to set ptl and check if this request has already been submitted. + * + * Must be inside lock as we might run into a lost update problem + * otherwise: If this were outside of the lock, cancellation in + * ssh_rtl_cancel_nonpending() may run after we've set the ptl + * reference but before we enter the lock. In that case, we'd detect + * that the request is being added to the queue and would try to remove + * it from that, but removal might fail because it hasn't actually been + * added yet. By putting this cmpxchg in the critical section, we + * ensure that the queuing detection only triggers when we are already + * in the critical section and the remove process will wait until the + * push operation has been completed (via lock) due to that. Only then, + * we can safely try to remove it. + */ + if (cmpxchg(&rqst->packet.ptl, NULL, &rtl->ptl)) { + spin_unlock(&rtl->queue.lock); + return -EALREADY; + } + + /* + * Ensure that we set ptl reference before we continue modifying state. + * This is required for non-pending cancellation. This barrier is paired + * with the one in ssh_rtl_cancel_nonpending(). + * + * By setting the ptl reference before we test for "locked", we can + * check if the "locked" test may have already run. See comments in + * ssh_rtl_cancel_nonpending() for more detail. + */ + smp_mb__after_atomic(); + + if (test_bit(SSH_RTL_SF_SHUTDOWN_BIT, &rtl->state)) { + spin_unlock(&rtl->queue.lock); + return -ESHUTDOWN; + } + + if (test_bit(SSH_REQUEST_SF_LOCKED_BIT, &rqst->state)) { + spin_unlock(&rtl->queue.lock); + return -EINVAL; + } + + set_bit(SSH_REQUEST_SF_QUEUED_BIT, &rqst->state); + list_add_tail(&ssh_request_get(rqst)->node, &rtl->queue.head); + + spin_unlock(&rtl->queue.lock); + + ssh_rtl_tx_schedule(rtl); + return 0; +} + +static void ssh_rtl_timeout_reaper_mod(struct ssh_rtl *rtl, ktime_t now, + ktime_t expires) +{ + unsigned long delta = msecs_to_jiffies(ktime_ms_delta(expires, now)); + ktime_t aexp = ktime_add(expires, SSH_RTL_REQUEST_TIMEOUT_RESOLUTION); + + spin_lock(&rtl->rtx_timeout.lock); + + /* Re-adjust / schedule reaper only if it is above resolution delta. */ + if (ktime_before(aexp, rtl->rtx_timeout.expires)) { + rtl->rtx_timeout.expires = expires; + mod_delayed_work(system_wq, &rtl->rtx_timeout.reaper, delta); + } + + spin_unlock(&rtl->rtx_timeout.lock); +} + +static void ssh_rtl_timeout_start(struct ssh_request *rqst) +{ + struct ssh_rtl *rtl = ssh_request_rtl(rqst); + ktime_t timestamp = ktime_get_coarse_boottime(); + ktime_t timeout = rtl->rtx_timeout.timeout; + + if (test_bit(SSH_REQUEST_SF_LOCKED_BIT, &rqst->state)) + return; + + /* + * Note: The timestamp gets set only once. This happens on the packet + * callback. All other access to it is read-only. + */ + WRITE_ONCE(rqst->timestamp, timestamp); + /* + * Ensure timestamp is set before starting the reaper. Paired with + * implicit barrier following check on ssh_request_get_expiration() in + * ssh_rtl_timeout_reap. + */ + smp_mb__after_atomic(); + + ssh_rtl_timeout_reaper_mod(rtl, timestamp, timestamp + timeout); +} + +static void ssh_rtl_complete(struct ssh_rtl *rtl, + const struct ssh_command *command, + const struct ssam_span *command_data) +{ + struct ssh_request *r = NULL; + struct ssh_request *p, *n; + u16 rqid = get_unaligned_le16(&command->rqid); + + /* + * Get request from pending based on request ID and mark it as response + * received and locked. + */ + spin_lock(&rtl->pending.lock); + list_for_each_entry_safe(p, n, &rtl->pending.head, node) { + /* We generally expect requests to be processed in order. */ + if (unlikely(ssh_request_get_rqid(p) != rqid)) + continue; + + /* + * Mark as "response received" and "locked" as we're going to + * complete it. + */ + set_bit(SSH_REQUEST_SF_LOCKED_BIT, &p->state); + set_bit(SSH_REQUEST_SF_RSPRCVD_BIT, &p->state); + /* Ensure state never gets zero. */ + smp_mb__before_atomic(); + clear_bit(SSH_REQUEST_SF_PENDING_BIT, &p->state); + + atomic_dec(&rtl->pending.count); + list_del(&p->node); + + r = p; + break; + } + spin_unlock(&rtl->pending.lock); + + if (!r) { + rtl_warn(rtl, "rtl: dropping unexpected command message (rqid = %#06x)\n", + rqid); + return; + } + + /* If the request hasn't been completed yet, we will do this now. */ + if (test_and_set_bit(SSH_REQUEST_SF_COMPLETED_BIT, &r->state)) { + ssh_request_put(r); + ssh_rtl_tx_schedule(rtl); + return; + } + + /* + * Make sure the request has been transmitted. In case of a sequenced + * request, we are guaranteed that the completion callback will run on + * the receiver thread directly when the ACK for the packet has been + * received. Similarly, this function is guaranteed to run on the + * receiver thread. Thus we are guaranteed that if the packet has been + * successfully transmitted and received an ACK, the transmitted flag + * has been set and is visible here. + * + * We are currently not handling unsequenced packets here, as those + * should never expect a response as ensured in ssh_rtl_submit. If this + * ever changes, one would have to test for + * + * (r->state & (transmitting | transmitted)) + * + * on unsequenced packets to determine if they could have been + * transmitted. There are no synchronization guarantees as in the + * sequenced case, since, in this case, the callback function will not + * run on the same thread. Thus an exact determination is impossible. + */ + if (!test_bit(SSH_REQUEST_SF_TRANSMITTED_BIT, &r->state)) { + rtl_err(rtl, "rtl: received response before ACK for request (rqid = %#06x)\n", + rqid); + + /* + * NB: Timeout has already been canceled, request already been + * removed from pending and marked as locked and completed. As + * we receive a "false" response, the packet might still be + * queued though. + */ + ssh_rtl_queue_remove(r); + + ssh_rtl_complete_with_status(r, -EREMOTEIO); + ssh_request_put(r); + + ssh_rtl_tx_schedule(rtl); + return; + } + + /* + * NB: Timeout has already been canceled, request already been + * removed from pending and marked as locked and completed. The request + * can also not be queued any more, as it has been marked as + * transmitting and later transmitted. Thus no need to remove it from + * anywhere. + */ + + ssh_rtl_complete_with_rsp(r, command, command_data); + ssh_request_put(r); + + ssh_rtl_tx_schedule(rtl); +} + +static bool ssh_rtl_cancel_nonpending(struct ssh_request *r) +{ + struct ssh_rtl *rtl; + unsigned long flags, fixed; + bool remove; + + /* + * Handle unsubmitted request: Try to mark the packet as locked, + * expecting the state to be zero (i.e. unsubmitted). Note that, if + * setting the state worked, we might still be adding the packet to the + * queue in a currently executing submit call. In that case, however, + * ptl reference must have been set previously, as locked is checked + * after setting ptl. Furthermore, when the ptl reference is set, the + * submission process is guaranteed to have entered the critical + * section. Thus only if we successfully locked this request and ptl is + * NULL, we have successfully removed the request, i.e. we are + * guaranteed that, due to the "locked" check in ssh_rtl_submit(), the + * packet will never be added. Otherwise, we need to try and grab it + * from the queue, where we are now guaranteed that the packet is or has + * been due to the critical section. + * + * Note that if the cmpxchg() fails, we are guaranteed that ptl has + * been set and is non-NULL, as states can only be nonzero after this + * has been set. Also note that we need to fetch the static (type) + * flags to ensure that they don't cause the cmpxchg() to fail. + */ + fixed = READ_ONCE(r->state) & SSH_REQUEST_FLAGS_TY_MASK; + flags = cmpxchg(&r->state, fixed, SSH_REQUEST_SF_LOCKED_BIT); + + /* + * Force correct ordering with regards to state and ptl reference access + * to safe-guard cancellation to concurrent submission against a + * lost-update problem. First try to exchange state, then also check + * ptl if that worked. This barrier is paired with the + * one in ssh_rtl_submit(). + */ + smp_mb__after_atomic(); + + if (flags == fixed && !READ_ONCE(r->packet.ptl)) { + if (test_and_set_bit(SSH_REQUEST_SF_COMPLETED_BIT, &r->state)) + return true; + + ssh_rtl_complete_with_status(r, -ECANCELED); + return true; + } + + rtl = ssh_request_rtl(r); + spin_lock(&rtl->queue.lock); + + /* + * Note: 1) Requests cannot be re-submitted. 2) If a request is + * queued, it cannot be "transmitting"/"pending" yet. Thus, if we + * successfully remove the request here, we have removed all its + * occurrences in the system. + */ + + remove = test_and_clear_bit(SSH_REQUEST_SF_QUEUED_BIT, &r->state); + if (!remove) { + spin_unlock(&rtl->queue.lock); + return false; + } + + set_bit(SSH_REQUEST_SF_LOCKED_BIT, &r->state); + list_del(&r->node); + + spin_unlock(&rtl->queue.lock); + + ssh_request_put(r); /* Drop reference obtained from queue. */ + + if (test_and_set_bit(SSH_REQUEST_SF_COMPLETED_BIT, &r->state)) + return true; + + ssh_rtl_complete_with_status(r, -ECANCELED); + return true; +} + +static bool ssh_rtl_cancel_pending(struct ssh_request *r) +{ + /* If the packet is already locked, it's going to be removed shortly. */ + if (test_and_set_bit(SSH_REQUEST_SF_LOCKED_BIT, &r->state)) + return true; + + /* + * Now that we have locked the packet, we have guaranteed that it can't + * be added to the system any more. If ptl is NULL, the locked + * check in ssh_rtl_submit() has not been run and any submission, + * currently in progress or called later, won't add the packet. Thus we + * can directly complete it. + * + * The implicit memory barrier of test_and_set_bit() should be enough + * to ensure that the correct order (first lock, then check ptl) is + * ensured. This is paired with the barrier in ssh_rtl_submit(). + */ + if (!READ_ONCE(r->packet.ptl)) { + if (test_and_set_bit(SSH_REQUEST_SF_COMPLETED_BIT, &r->state)) + return true; + + ssh_rtl_complete_with_status(r, -ECANCELED); + return true; + } + + /* + * Try to cancel the packet. If the packet has not been completed yet, + * this will subsequently (and synchronously) call the completion + * callback of the packet, which will complete the request. + */ + ssh_ptl_cancel(&r->packet); + + /* + * If the packet has been completed with success, i.e. has not been + * canceled by the above call, the request may not have been completed + * yet (may be waiting for a response). Check if we need to do this + * here. + */ + if (test_and_set_bit(SSH_REQUEST_SF_COMPLETED_BIT, &r->state)) + return true; + + ssh_rtl_queue_remove(r); + ssh_rtl_pending_remove(r); + ssh_rtl_complete_with_status(r, -ECANCELED); + + return true; +} + +/** + * ssh_rtl_cancel() - Cancel request. + * @rqst: The request to cancel. + * @pending: Whether to also cancel pending requests. + * + * Cancels the given request. If @pending is %false, this will not cancel + * pending requests, i.e. requests that have already been submitted to the + * packet layer but not been completed yet. If @pending is %true, this will + * cancel the given request regardless of the state it is in. + * + * If the request has been canceled by calling this function, both completion + * and release callbacks of the request will be executed in a reasonable + * time-frame. This may happen during execution of this function, however, + * there is no guarantee for this. For example, a request currently + * transmitting will be canceled/completed only after transmission has + * completed, and the respective callbacks will be executed on the transmitter + * thread, which may happen during, but also some time after execution of the + * cancel function. + * + * Return: Returns %true if the given request has been canceled or completed, + * either by this function or prior to calling this function, %false + * otherwise. If @pending is %true, this function will always return %true. + */ +bool ssh_rtl_cancel(struct ssh_request *rqst, bool pending) +{ + struct ssh_rtl *rtl; + bool canceled; + + if (test_and_set_bit(SSH_REQUEST_SF_CANCELED_BIT, &rqst->state)) + return true; + + if (pending) + canceled = ssh_rtl_cancel_pending(rqst); + else + canceled = ssh_rtl_cancel_nonpending(rqst); + + /* Note: rtl may be NULL if request has not been submitted yet. */ + rtl = ssh_request_rtl(rqst); + if (canceled && rtl) + ssh_rtl_tx_schedule(rtl); + + return canceled; +} + +static void ssh_rtl_packet_callback(struct ssh_packet *p, int status) +{ + struct ssh_request *r = to_ssh_request(p); + + if (unlikely(status)) { + set_bit(SSH_REQUEST_SF_LOCKED_BIT, &r->state); + + if (test_and_set_bit(SSH_REQUEST_SF_COMPLETED_BIT, &r->state)) + return; + + /* + * The packet may get canceled even though it has not been + * submitted yet. The request may still be queued. Check the + * queue and remove it if necessary. As the timeout would have + * been started in this function on success, there's no need + * to cancel it here. + */ + ssh_rtl_queue_remove(r); + ssh_rtl_pending_remove(r); + ssh_rtl_complete_with_status(r, status); + + ssh_rtl_tx_schedule(ssh_request_rtl(r)); + return; + } + + /* Update state: Mark as transmitted and clear transmitting. */ + set_bit(SSH_REQUEST_SF_TRANSMITTED_BIT, &r->state); + /* Ensure state never gets zero. */ + smp_mb__before_atomic(); + clear_bit(SSH_REQUEST_SF_TRANSMITTING_BIT, &r->state); + + /* If we expect a response, we just need to start the timeout. */ + if (test_bit(SSH_REQUEST_TY_HAS_RESPONSE_BIT, &r->state)) { + /* + * Note: This is the only place where the timestamp gets set, + * all other access to it is read-only. + */ + ssh_rtl_timeout_start(r); + return; + } + + /* + * If we don't expect a response, lock, remove, and complete the + * request. Note that, at this point, the request is guaranteed to have + * left the queue and no timeout has been started. Thus we only need to + * remove it from pending. If the request has already been completed (it + * may have been canceled) return. + */ + + set_bit(SSH_REQUEST_SF_LOCKED_BIT, &r->state); + if (test_and_set_bit(SSH_REQUEST_SF_COMPLETED_BIT, &r->state)) + return; + + ssh_rtl_pending_remove(r); + ssh_rtl_complete_with_status(r, 0); + + ssh_rtl_tx_schedule(ssh_request_rtl(r)); +} + +static ktime_t ssh_request_get_expiration(struct ssh_request *r, ktime_t timeout) +{ + ktime_t timestamp = READ_ONCE(r->timestamp); + + if (timestamp != KTIME_MAX) + return ktime_add(timestamp, timeout); + else + return KTIME_MAX; +} + +static void ssh_rtl_timeout_reap(struct work_struct *work) +{ + struct ssh_rtl *rtl = to_ssh_rtl(work, rtx_timeout.reaper.work); + struct ssh_request *r, *n; + LIST_HEAD(claimed); + ktime_t now = ktime_get_coarse_boottime(); + ktime_t timeout = rtl->rtx_timeout.timeout; + ktime_t next = KTIME_MAX; + + /* + * Mark reaper as "not pending". This is done before checking any + * requests to avoid lost-update type problems. + */ + spin_lock(&rtl->rtx_timeout.lock); + rtl->rtx_timeout.expires = KTIME_MAX; + spin_unlock(&rtl->rtx_timeout.lock); + + spin_lock(&rtl->pending.lock); + list_for_each_entry_safe(r, n, &rtl->pending.head, node) { + ktime_t expires = ssh_request_get_expiration(r, timeout); + + /* + * Check if the timeout hasn't expired yet. Find out next + * expiration date to be handled after this run. + */ + if (ktime_after(expires, now)) { + next = ktime_before(expires, next) ? expires : next; + continue; + } + + /* Avoid further transitions if locked. */ + if (test_and_set_bit(SSH_REQUEST_SF_LOCKED_BIT, &r->state)) + continue; + + /* + * We have now marked the packet as locked. Thus it cannot be + * added to the pending or queued lists again after we've + * removed it here. We can therefore re-use the node of this + * packet temporarily. + */ + + clear_bit(SSH_REQUEST_SF_PENDING_BIT, &r->state); + + atomic_dec(&rtl->pending.count); + list_del(&r->node); + + list_add_tail(&r->node, &claimed); + } + spin_unlock(&rtl->pending.lock); + + /* Cancel and complete the request. */ + list_for_each_entry_safe(r, n, &claimed, node) { + /* + * At this point we've removed the packet from pending. This + * means that we've obtained the last (only) reference of the + * system to it. Thus we can just complete it. + */ + if (!test_and_set_bit(SSH_REQUEST_SF_COMPLETED_BIT, &r->state)) + ssh_rtl_complete_with_status(r, -ETIMEDOUT); + + /* + * Drop the reference we've obtained by removing it from the + * pending set. + */ + list_del(&r->node); + ssh_request_put(r); + } + + /* Ensure that the reaper doesn't run again immediately. */ + next = max(next, ktime_add(now, SSH_RTL_REQUEST_TIMEOUT_RESOLUTION)); + if (next != KTIME_MAX) + ssh_rtl_timeout_reaper_mod(rtl, now, next); + + ssh_rtl_tx_schedule(rtl); +} + +static void ssh_rtl_rx_event(struct ssh_rtl *rtl, const struct ssh_command *cmd, + const struct ssam_span *data) +{ + rtl_dbg(rtl, "rtl: handling event (rqid: %#06x)\n", + get_unaligned_le16(&cmd->rqid)); + + rtl->ops.handle_event(rtl, cmd, data); +} + +static void ssh_rtl_rx_command(struct ssh_ptl *p, const struct ssam_span *data) +{ + struct ssh_rtl *rtl = to_ssh_rtl(p, ptl); + struct device *dev = &p->serdev->dev; + struct ssh_command *command; + struct ssam_span command_data; + + if (sshp_parse_command(dev, data, &command, &command_data)) + return; + + if (ssh_rqid_is_event(get_unaligned_le16(&command->rqid))) + ssh_rtl_rx_event(rtl, command, &command_data); + else + ssh_rtl_complete(rtl, command, &command_data); +} + +static void ssh_rtl_rx_data(struct ssh_ptl *p, const struct ssam_span *data) +{ + if (!data->len) { + ptl_err(p, "rtl: rx: no data frame payload\n"); + return; + } + + switch (data->ptr[0]) { + case SSH_PLD_TYPE_CMD: + ssh_rtl_rx_command(p, data); + break; + + default: + ptl_err(p, "rtl: rx: unknown frame payload type (type: %#04x)\n", + data->ptr[0]); + break; + } +} + +static void ssh_rtl_packet_release(struct ssh_packet *p) +{ + struct ssh_request *rqst; + + rqst = to_ssh_request(p); + rqst->ops->release(rqst); +} + +static const struct ssh_packet_ops ssh_rtl_packet_ops = { + .complete = ssh_rtl_packet_callback, + .release = ssh_rtl_packet_release, +}; + +/** + * ssh_request_init() - Initialize SSH request. + * @rqst: The request to initialize. + * @flags: Request flags, determining the type of the request. + * @ops: Request operations. + * + * Initializes the given SSH request and underlying packet. Sets the message + * buffer pointer to %NULL and the message buffer length to zero. This buffer + * has to be set separately via ssh_request_set_data() before submission and + * must contain a valid SSH request message. + * + * Return: Returns zero on success or %-EINVAL if the given flags are invalid. + */ +int ssh_request_init(struct ssh_request *rqst, enum ssam_request_flags flags, + const struct ssh_request_ops *ops) +{ + unsigned long type = BIT(SSH_PACKET_TY_BLOCKING_BIT); + + /* Unsequenced requests cannot have a response. */ + if (flags & SSAM_REQUEST_UNSEQUENCED && flags & SSAM_REQUEST_HAS_RESPONSE) + return -EINVAL; + + if (!(flags & SSAM_REQUEST_UNSEQUENCED)) + type |= BIT(SSH_PACKET_TY_SEQUENCED_BIT); + + ssh_packet_init(&rqst->packet, type, SSH_PACKET_PRIORITY(DATA, 0), + &ssh_rtl_packet_ops); + + INIT_LIST_HEAD(&rqst->node); + + rqst->state = 0; + if (flags & SSAM_REQUEST_HAS_RESPONSE) + rqst->state |= BIT(SSH_REQUEST_TY_HAS_RESPONSE_BIT); + + rqst->timestamp = KTIME_MAX; + rqst->ops = ops; + + return 0; +} + +/** + * ssh_rtl_init() - Initialize request transport layer. + * @rtl: The request transport layer to initialize. + * @serdev: The underlying serial device, i.e. the lower-level transport. + * @ops: Request transport layer operations. + * + * Initializes the given request transport layer and associated packet + * transport layer. Transmitter and receiver threads must be started + * separately via ssh_rtl_tx_start() and ssh_rtl_rx_start(), after the + * request-layer has been initialized and the lower-level serial device layer + * has been set up. + * + * Return: Returns zero on success and a nonzero error code on failure. + */ +int ssh_rtl_init(struct ssh_rtl *rtl, struct serdev_device *serdev, + const struct ssh_rtl_ops *ops) +{ + struct ssh_ptl_ops ptl_ops; + int status; + + ptl_ops.data_received = ssh_rtl_rx_data; + + status = ssh_ptl_init(&rtl->ptl, serdev, &ptl_ops); + if (status) + return status; + + spin_lock_init(&rtl->queue.lock); + INIT_LIST_HEAD(&rtl->queue.head); + + spin_lock_init(&rtl->pending.lock); + INIT_LIST_HEAD(&rtl->pending.head); + atomic_set_release(&rtl->pending.count, 0); + + INIT_WORK(&rtl->tx.work, ssh_rtl_tx_work_fn); + + spin_lock_init(&rtl->rtx_timeout.lock); + rtl->rtx_timeout.timeout = SSH_RTL_REQUEST_TIMEOUT; + rtl->rtx_timeout.expires = KTIME_MAX; + INIT_DELAYED_WORK(&rtl->rtx_timeout.reaper, ssh_rtl_timeout_reap); + + rtl->ops = *ops; + + return 0; +} + +/** + * ssh_rtl_destroy() - Deinitialize request transport layer. + * @rtl: The request transport layer to deinitialize. + * + * Deinitializes the given request transport layer and frees resources + * associated with it. If receiver and/or transmitter threads have been + * started, the layer must first be shut down via ssh_rtl_shutdown() before + * this function can be called. + */ +void ssh_rtl_destroy(struct ssh_rtl *rtl) +{ + ssh_ptl_destroy(&rtl->ptl); +} + +/** + * ssh_rtl_tx_start() - Start request transmitter and receiver. + * @rtl: The request transport layer. + * + * Return: Returns zero on success, a negative error code on failure. + */ +int ssh_rtl_start(struct ssh_rtl *rtl) +{ + int status; + + status = ssh_ptl_tx_start(&rtl->ptl); + if (status) + return status; + + ssh_rtl_tx_schedule(rtl); + + status = ssh_ptl_rx_start(&rtl->ptl); + if (status) { + ssh_rtl_flush(rtl, msecs_to_jiffies(5000)); + ssh_ptl_tx_stop(&rtl->ptl); + return status; + } + + return 0; +} + +struct ssh_flush_request { + struct ssh_request base; + struct completion completion; + int status; +}; + +static void ssh_rtl_flush_request_complete(struct ssh_request *r, + const struct ssh_command *cmd, + const struct ssam_span *data, + int status) +{ + struct ssh_flush_request *rqst; + + rqst = container_of(r, struct ssh_flush_request, base); + rqst->status = status; +} + +static void ssh_rtl_flush_request_release(struct ssh_request *r) +{ + struct ssh_flush_request *rqst; + + rqst = container_of(r, struct ssh_flush_request, base); + complete_all(&rqst->completion); +} + +static const struct ssh_request_ops ssh_rtl_flush_request_ops = { + .complete = ssh_rtl_flush_request_complete, + .release = ssh_rtl_flush_request_release, +}; + +/** + * ssh_rtl_flush() - Flush the request transport layer. + * @rtl: request transport layer + * @timeout: timeout for the flush operation in jiffies + * + * Queue a special flush request and wait for its completion. This request + * will be completed after all other currently queued and pending requests + * have been completed. Instead of a normal data packet, this request submits + * a special flush packet, meaning that upon completion, also the underlying + * packet transport layer has been flushed. + * + * Flushing the request layer guarantees that all previously submitted + * requests have been fully completed before this call returns. Additionally, + * flushing blocks execution of all later submitted requests until the flush + * has been completed. + * + * If the caller ensures that no new requests are submitted after a call to + * this function, the request transport layer is guaranteed to have no + * remaining requests when this call returns. The same guarantee does not hold + * for the packet layer, on which control packets may still be queued after + * this call. + * + * Return: Returns zero on success, %-ETIMEDOUT if the flush timed out and has + * been canceled as a result of the timeout, or %-ESHUTDOWN if the packet + * and/or request transport layer has been shut down before this call. May + * also return %-EINTR if the underlying packet transmission has been + * interrupted. + */ +int ssh_rtl_flush(struct ssh_rtl *rtl, unsigned long timeout) +{ + const unsigned int init_flags = SSAM_REQUEST_UNSEQUENCED; + struct ssh_flush_request rqst; + int status; + + ssh_request_init(&rqst.base, init_flags, &ssh_rtl_flush_request_ops); + rqst.base.packet.state |= BIT(SSH_PACKET_TY_FLUSH_BIT); + rqst.base.packet.priority = SSH_PACKET_PRIORITY(FLUSH, 0); + rqst.base.state |= BIT(SSH_REQUEST_TY_FLUSH_BIT); + + init_completion(&rqst.completion); + + status = ssh_rtl_submit(rtl, &rqst.base); + if (status) + return status; + + ssh_request_put(&rqst.base); + + if (!wait_for_completion_timeout(&rqst.completion, timeout)) { + ssh_rtl_cancel(&rqst.base, true); + wait_for_completion(&rqst.completion); + } + + WARN_ON(rqst.status != 0 && rqst.status != -ECANCELED && + rqst.status != -ESHUTDOWN && rqst.status != -EINTR); + + return rqst.status == -ECANCELED ? -ETIMEDOUT : rqst.status; +} + +/** + * ssh_rtl_shutdown() - Shut down request transport layer. + * @rtl: The request transport layer. + * + * Shuts down the request transport layer, removing and canceling all queued + * and pending requests. Requests canceled by this operation will be completed + * with %-ESHUTDOWN as status. Receiver and transmitter threads will be + * stopped, the lower-level packet layer will be shutdown. + * + * As a result of this function, the transport layer will be marked as shut + * down. Submission of requests after the transport layer has been shut down + * will fail with %-ESHUTDOWN. + */ +void ssh_rtl_shutdown(struct ssh_rtl *rtl) +{ + struct ssh_request *r, *n; + LIST_HEAD(claimed); + int pending; + + set_bit(SSH_RTL_SF_SHUTDOWN_BIT, &rtl->state); + /* + * Ensure that the layer gets marked as shut-down before actually + * stopping it. In combination with the check in ssh_rtl_submit(), + * this guarantees that no new requests can be added and all already + * queued requests are properly canceled. + */ + smp_mb__after_atomic(); + + /* Remove requests from queue. */ + spin_lock(&rtl->queue.lock); + list_for_each_entry_safe(r, n, &rtl->queue.head, node) { + set_bit(SSH_REQUEST_SF_LOCKED_BIT, &r->state); + /* Ensure state never gets zero. */ + smp_mb__before_atomic(); + clear_bit(SSH_REQUEST_SF_QUEUED_BIT, &r->state); + + list_del(&r->node); + list_add_tail(&r->node, &claimed); + } + spin_unlock(&rtl->queue.lock); + + /* + * We have now guaranteed that the queue is empty and no more new + * requests can be submitted (i.e. it will stay empty). This means that + * calling ssh_rtl_tx_schedule() will not schedule tx.work any more. So + * we can simply call cancel_work_sync() on tx.work here and when that + * returns, we've locked it down. This also means that after this call, + * we don't submit any more packets to the underlying packet layer, so + * we can also shut that down. + */ + + cancel_work_sync(&rtl->tx.work); + ssh_ptl_shutdown(&rtl->ptl); + cancel_delayed_work_sync(&rtl->rtx_timeout.reaper); + + /* + * Shutting down the packet layer should also have canceled all + * requests. Thus the pending set should be empty. Attempt to handle + * this gracefully anyways, even though this should be dead code. + */ + + pending = atomic_read(&rtl->pending.count); + if (WARN_ON(pending)) { + spin_lock(&rtl->pending.lock); + list_for_each_entry_safe(r, n, &rtl->pending.head, node) { + set_bit(SSH_REQUEST_SF_LOCKED_BIT, &r->state); + /* Ensure state never gets zero. */ + smp_mb__before_atomic(); + clear_bit(SSH_REQUEST_SF_PENDING_BIT, &r->state); + + list_del(&r->node); + list_add_tail(&r->node, &claimed); + } + spin_unlock(&rtl->pending.lock); + } + + /* Finally, cancel and complete the requests we claimed before. */ + list_for_each_entry_safe(r, n, &claimed, node) { + /* + * We need test_and_set() because we still might compete with + * cancellation. + */ + if (!test_and_set_bit(SSH_REQUEST_SF_COMPLETED_BIT, &r->state)) + ssh_rtl_complete_with_status(r, -ESHUTDOWN); + + /* + * Drop the reference we've obtained by removing it from the + * lists. + */ + list_del(&r->node); + ssh_request_put(r); + } +} diff --git a/drivers/platform/surface/aggregator/ssh_request_layer.h b/drivers/platform/surface/aggregator/ssh_request_layer.h new file mode 100644 index 000000000000..cb35815858d1 --- /dev/null +++ b/drivers/platform/surface/aggregator/ssh_request_layer.h @@ -0,0 +1,143 @@ +/* SPDX-License-Identifier: GPL-2.0+ */ +/* + * SSH request transport layer. + * + * Copyright (C) 2019-2020 Maximilian Luz + */ + +#ifndef _SURFACE_AGGREGATOR_SSH_REQUEST_LAYER_H +#define _SURFACE_AGGREGATOR_SSH_REQUEST_LAYER_H + +#include +#include +#include +#include +#include + +#include +#include + +#include "ssh_packet_layer.h" + +/** + * enum ssh_rtl_state_flags - State-flags for &struct ssh_rtl. + * + * @SSH_RTL_SF_SHUTDOWN_BIT: + * Indicates that the request transport layer has been shut down or is + * being shut down and should not accept any new requests. + */ +enum ssh_rtl_state_flags { + SSH_RTL_SF_SHUTDOWN_BIT, +}; + +/** + * struct ssh_rtl_ops - Callback operations for request transport layer. + * @handle_event: Function called when a SSH event has been received. The + * specified function takes the request layer, received command + * struct, and corresponding payload as arguments. If the event + * has no payload, the payload span is empty (not %NULL). + */ +struct ssh_rtl_ops { + void (*handle_event)(struct ssh_rtl *rtl, const struct ssh_command *cmd, + const struct ssam_span *data); +}; + +/** + * struct ssh_rtl - SSH request transport layer. + * @ptl: Underlying packet transport layer. + * @state: State(-flags) of the transport layer. + * @queue: Request submission queue. + * @queue.lock: Lock for modifying the request submission queue. + * @queue.head: List-head of the request submission queue. + * @pending: Set/list of pending requests. + * @pending.lock: Lock for modifying the request set. + * @pending.head: List-head of the pending set/list. + * @pending.count: Number of currently pending requests. + * @tx: Transmitter subsystem. + * @tx.work: Transmitter work item. + * @rtx_timeout: Retransmission timeout subsystem. + * @rtx_timeout.lock: Lock for modifying the retransmission timeout reaper. + * @rtx_timeout.timeout: Timeout interval for retransmission. + * @rtx_timeout.expires: Time specifying when the reaper work is next scheduled. + * @rtx_timeout.reaper: Work performing timeout checks and subsequent actions. + * @ops: Request layer operations. + */ +struct ssh_rtl { + struct ssh_ptl ptl; + unsigned long state; + + struct { + spinlock_t lock; + struct list_head head; + } queue; + + struct { + spinlock_t lock; + struct list_head head; + atomic_t count; + } pending; + + struct { + struct work_struct work; + } tx; + + struct { + spinlock_t lock; + ktime_t timeout; + ktime_t expires; + struct delayed_work reaper; + } rtx_timeout; + + struct ssh_rtl_ops ops; +}; + +#define rtl_dbg(r, fmt, ...) ptl_dbg(&(r)->ptl, fmt, ##__VA_ARGS__) +#define rtl_info(p, fmt, ...) ptl_info(&(p)->ptl, fmt, ##__VA_ARGS__) +#define rtl_warn(r, fmt, ...) ptl_warn(&(r)->ptl, fmt, ##__VA_ARGS__) +#define rtl_err(r, fmt, ...) ptl_err(&(r)->ptl, fmt, ##__VA_ARGS__) +#define rtl_dbg_cond(r, fmt, ...) __ssam_prcond(rtl_dbg, r, fmt, ##__VA_ARGS__) + +#define to_ssh_rtl(ptr, member) \ + container_of(ptr, struct ssh_rtl, member) + +/** + * ssh_rtl_get_device() - Get device associated with request transport layer. + * @rtl: The request transport layer. + * + * Return: Returns the device on which the given request transport layer + * builds upon. + */ +static inline struct device *ssh_rtl_get_device(struct ssh_rtl *rtl) +{ + return ssh_ptl_get_device(&rtl->ptl); +} + +/** + * ssh_request_rtl() - Get request transport layer associated with request. + * @rqst: The request to get the request transport layer reference for. + * + * Return: Returns the &struct ssh_rtl associated with the given SSH request. + */ +static inline struct ssh_rtl *ssh_request_rtl(struct ssh_request *rqst) +{ + struct ssh_ptl *ptl; + + ptl = READ_ONCE(rqst->packet.ptl); + return likely(ptl) ? to_ssh_rtl(ptl, ptl) : NULL; +} + +int ssh_rtl_submit(struct ssh_rtl *rtl, struct ssh_request *rqst); +bool ssh_rtl_cancel(struct ssh_request *rqst, bool pending); + +int ssh_rtl_init(struct ssh_rtl *rtl, struct serdev_device *serdev, + const struct ssh_rtl_ops *ops); + +int ssh_rtl_start(struct ssh_rtl *rtl); +int ssh_rtl_flush(struct ssh_rtl *rtl, unsigned long timeout); +void ssh_rtl_shutdown(struct ssh_rtl *rtl); +void ssh_rtl_destroy(struct ssh_rtl *rtl); + +int ssh_request_init(struct ssh_request *rqst, enum ssam_request_flags flags, + const struct ssh_request_ops *ops); + +#endif /* _SURFACE_AGGREGATOR_SSH_REQUEST_LAYER_H */ -- cgit v1.2.3 From 44b84ee7b437dd7f869341b4b671963161a34a9f Mon Sep 17 00:00:00 2001 From: Maximilian Luz Date: Mon, 21 Dec 2020 19:39:52 +0100 Subject: platform/surface: aggregator: Add control packet allocation caching Surface Serial Hub communication is, in its core, packet based. Each sequenced packet requires to be acknowledged, via an ACK-type control packet. In case invalid data has been received by the driver, a NAK-type (not-acknowledge/negative acknowledge) control packet is sent, triggering retransmission. Control packets are therefore a core communication primitive and used frequently enough (with every sequenced packet transmission sent by the embedded controller, including events and request responses) that it may warrant caching their allocations to reduce possible memory fragmentation. Signed-off-by: Maximilian Luz Reviewed-by: Hans de Goede Link: https://lore.kernel.org/r/20201221183959.1186143-3-luzmaximilian@gmail.com Signed-off-by: Hans de Goede --- drivers/platform/surface/aggregator/core.c | 27 ++++++++++++- .../platform/surface/aggregator/ssh_packet_layer.c | 47 +++++++++++++++++----- .../platform/surface/aggregator/ssh_packet_layer.h | 3 ++ 3 files changed, 67 insertions(+), 10 deletions(-) (limited to 'drivers/platform/surface') diff --git a/drivers/platform/surface/aggregator/core.c b/drivers/platform/surface/aggregator/core.c index 18e0e9e34e7b..60d312f71436 100644 --- a/drivers/platform/surface/aggregator/core.c +++ b/drivers/platform/surface/aggregator/core.c @@ -780,7 +780,32 @@ static struct serdev_device_driver ssam_serial_hub = { .probe_type = PROBE_PREFER_ASYNCHRONOUS, }, }; -module_serdev_device_driver(ssam_serial_hub); + + +/* -- Module setup. --------------------------------------------------------- */ + +static int __init ssam_core_init(void) +{ + int status; + + status = ssh_ctrl_packet_cache_init(); + if (status) + return status; + + status = serdev_device_driver_register(&ssam_serial_hub); + if (status) + ssh_ctrl_packet_cache_destroy(); + + return status; +} +module_init(ssam_core_init); + +static void __exit ssam_core_exit(void) +{ + serdev_device_driver_unregister(&ssam_serial_hub); + ssh_ctrl_packet_cache_destroy(); +} +module_exit(ssam_core_exit); MODULE_AUTHOR("Maximilian Luz "); MODULE_DESCRIPTION("Subsystem and Surface Serial Hub driver for Surface System Aggregator Module"); diff --git a/drivers/platform/surface/aggregator/ssh_packet_layer.c b/drivers/platform/surface/aggregator/ssh_packet_layer.c index 66e38fdc7963..23c2e31e7d0e 100644 --- a/drivers/platform/surface/aggregator/ssh_packet_layer.c +++ b/drivers/platform/surface/aggregator/ssh_packet_layer.c @@ -303,24 +303,53 @@ void ssh_packet_init(struct ssh_packet *packet, unsigned long type, packet->ops = ops; } +static struct kmem_cache *ssh_ctrl_packet_cache; + +/** + * ssh_ctrl_packet_cache_init() - Initialize the control packet cache. + */ +int ssh_ctrl_packet_cache_init(void) +{ + const unsigned int size = sizeof(struct ssh_packet) + SSH_MSG_LEN_CTRL; + const unsigned int align = __alignof__(struct ssh_packet); + struct kmem_cache *cache; + + cache = kmem_cache_create("ssam_ctrl_packet", size, align, 0, NULL); + if (!cache) + return -ENOMEM; + + ssh_ctrl_packet_cache = cache; + return 0; +} + +/** + * ssh_ctrl_packet_cache_destroy() - Deinitialize the control packet cache. + */ +void ssh_ctrl_packet_cache_destroy(void) +{ + kmem_cache_destroy(ssh_ctrl_packet_cache); + ssh_ctrl_packet_cache = NULL; +} + /** - * ssh_ctrl_packet_alloc() - Allocate control packet. + * ssh_ctrl_packet_alloc() - Allocate packet from control packet cache. * @packet: Where the pointer to the newly allocated packet should be stored. * @buffer: The buffer corresponding to this packet. * @flags: Flags used for allocation. * - * Allocates a packet and corresponding transport buffer. Sets the packet's - * buffer reference to the allocated buffer. The packet must be freed via - * ssh_ctrl_packet_free(), which will also free the corresponding buffer. The - * corresponding buffer must not be freed separately. Intended to be used with - * %ssh_ptl_ctrl_packet_ops as packet operations. + * Allocates a packet and corresponding transport buffer from the control + * packet cache. Sets the packet's buffer reference to the allocated buffer. + * The packet must be freed via ssh_ctrl_packet_free(), which will also free + * the corresponding buffer. The corresponding buffer must not be freed + * separately. Intended to be used with %ssh_ptl_ctrl_packet_ops as packet + * operations. * * Return: Returns zero on success, %-ENOMEM if the allocation failed. */ static int ssh_ctrl_packet_alloc(struct ssh_packet **packet, struct ssam_span *buffer, gfp_t flags) { - *packet = kzalloc(sizeof(**packet) + SSH_MSG_LEN_CTRL, flags); + *packet = kmem_cache_alloc(ssh_ctrl_packet_cache, flags); if (!*packet) return -ENOMEM; @@ -331,12 +360,12 @@ static int ssh_ctrl_packet_alloc(struct ssh_packet **packet, } /** - * ssh_ctrl_packet_free() - Free control packet. + * ssh_ctrl_packet_free() - Free packet allocated from control packet cache. * @p: The packet to free. */ static void ssh_ctrl_packet_free(struct ssh_packet *p) { - kfree(p); + kmem_cache_free(ssh_ctrl_packet_cache, p); } static const struct ssh_packet_ops ssh_ptl_ctrl_packet_ops = { diff --git a/drivers/platform/surface/aggregator/ssh_packet_layer.h b/drivers/platform/surface/aggregator/ssh_packet_layer.h index 058f111292ca..e8757d03f279 100644 --- a/drivers/platform/surface/aggregator/ssh_packet_layer.h +++ b/drivers/platform/surface/aggregator/ssh_packet_layer.h @@ -184,4 +184,7 @@ static inline void ssh_ptl_tx_wakeup_transfer(struct ssh_ptl *ptl) void ssh_packet_init(struct ssh_packet *packet, unsigned long type, u8 priority, const struct ssh_packet_ops *ops); +int ssh_ctrl_packet_cache_init(void); +void ssh_ctrl_packet_cache_destroy(void); + #endif /* _SURFACE_AGGREGATOR_SSH_PACKET_LAYER_H */ -- cgit v1.2.3 From 3a7081f610a0ff6385f38cf65a019383cd34bfdd Mon Sep 17 00:00:00 2001 From: Maximilian Luz Date: Mon, 21 Dec 2020 19:39:53 +0100 Subject: platform/surface: aggregator: Add event item allocation caching Event items are used for completing Surface Aggregator EC events, i.e. placing event command data and payload on a workqueue for later processing to avoid doing said processing directly on the receiver thread. This means that event items are allocated for each incoming event, regardless of that event being transmitted via sequenced or unsequenced packets. On the Surface Book 3 and Surface Laptop 3, touchpad HID input events (unsequenced), can constitute a larger amount of traffic, and therefore allocation of event items. This warrants caching event items to reduce memory fragmentation. The size of the cached objects is specifically tuned to accommodate keyboard and touchpad input events and their payloads on those devices. As a result, this effectively also covers most other event types. In case of a larger event payload, event item allocation will fall back to kzalloc(). Signed-off-by: Maximilian Luz Reviewed-by: Hans de Goede Link: https://lore.kernel.org/r/20201221183959.1186143-4-luzmaximilian@gmail.com Signed-off-by: Hans de Goede --- drivers/platform/surface/aggregator/controller.c | 86 +++++++++++++++++++++--- drivers/platform/surface/aggregator/controller.h | 9 +++ drivers/platform/surface/aggregator/core.c | 16 ++++- 3 files changed, 101 insertions(+), 10 deletions(-) (limited to 'drivers/platform/surface') diff --git a/drivers/platform/surface/aggregator/controller.c b/drivers/platform/surface/aggregator/controller.c index 488318cf2098..775a4509bece 100644 --- a/drivers/platform/surface/aggregator/controller.c +++ b/drivers/platform/surface/aggregator/controller.c @@ -513,14 +513,74 @@ static void ssam_nf_destroy(struct ssam_nf *nf) */ #define SSAM_CPLT_WQ_BATCH 10 +/* + * SSAM_EVENT_ITEM_CACHE_PAYLOAD_LEN - Maximum payload length for a cached + * &struct ssam_event_item. + * + * This length has been chosen to be accommodate standard touchpad and + * keyboard input events. Events with larger payloads will be allocated + * separately. + */ +#define SSAM_EVENT_ITEM_CACHE_PAYLOAD_LEN 32 + +static struct kmem_cache *ssam_event_item_cache; + +/** + * ssam_event_item_cache_init() - Initialize the event item cache. + */ +int ssam_event_item_cache_init(void) +{ + const unsigned int size = sizeof(struct ssam_event_item) + + SSAM_EVENT_ITEM_CACHE_PAYLOAD_LEN; + const unsigned int align = __alignof__(struct ssam_event_item); + struct kmem_cache *cache; + + cache = kmem_cache_create("ssam_event_item", size, align, 0, NULL); + if (!cache) + return -ENOMEM; + + ssam_event_item_cache = cache; + return 0; +} + +/** + * ssam_event_item_cache_destroy() - Deinitialize the event item cache. + */ +void ssam_event_item_cache_destroy(void) +{ + kmem_cache_destroy(ssam_event_item_cache); + ssam_event_item_cache = NULL; +} + +static void __ssam_event_item_free_cached(struct ssam_event_item *item) +{ + kmem_cache_free(ssam_event_item_cache, item); +} + +static void __ssam_event_item_free_generic(struct ssam_event_item *item) +{ + kfree(item); +} + +/** + * ssam_event_item_free() - Free the provided event item. + * @item: The event item to free. + */ +static void ssam_event_item_free(struct ssam_event_item *item) +{ + item->ops.free(item); +} + /** * ssam_event_item_alloc() - Allocate an event item with the given payload size. * @len: The event payload length. * @flags: The flags used for allocation. * - * Allocate an event item with the given payload size. Sets the item - * operations and payload length values. The item free callback (``ops.free``) - * should not be overwritten after this call. + * Allocate an event item with the given payload size, preferring allocation + * from the event item cache if the payload is small enough (i.e. smaller than + * %SSAM_EVENT_ITEM_CACHE_PAYLOAD_LEN). Sets the item operations and payload + * length values. The item free callback (``ops.free``) should not be + * overwritten after this call. * * Return: Returns the newly allocated event item. */ @@ -528,9 +588,19 @@ static struct ssam_event_item *ssam_event_item_alloc(size_t len, gfp_t flags) { struct ssam_event_item *item; - item = kzalloc(struct_size(item, event.data, len), flags); - if (!item) - return NULL; + if (len <= SSAM_EVENT_ITEM_CACHE_PAYLOAD_LEN) { + item = kmem_cache_alloc(ssam_event_item_cache, flags); + if (!item) + return NULL; + + item->ops.free = __ssam_event_item_free_cached; + } else { + item = kzalloc(struct_size(item, event.data, len), flags); + if (!item) + return NULL; + + item->ops.free = __ssam_event_item_free_generic; + } item->event.length = len; return item; @@ -692,7 +762,7 @@ static void ssam_event_queue_work_fn(struct work_struct *work) return; ssam_nf_call(nf, dev, item->rqid, &item->event); - kfree(item); + ssam_event_item_free(item); } while (--iterations); if (!ssam_event_queue_is_empty(queue)) @@ -900,7 +970,7 @@ static void ssam_handle_event(struct ssh_rtl *rtl, memcpy(&item->event.data[0], data->ptr, data->len); if (WARN_ON(ssam_cplt_submit_event(&ctrl->cplt, item))) - kfree(item); + ssam_event_item_free(item); } static const struct ssh_rtl_ops ssam_rtl_ops = { diff --git a/drivers/platform/surface/aggregator/controller.h b/drivers/platform/surface/aggregator/controller.h index 5ee9e966f1d7..8297d34e7489 100644 --- a/drivers/platform/surface/aggregator/controller.h +++ b/drivers/platform/surface/aggregator/controller.h @@ -80,12 +80,18 @@ struct ssam_cplt; * struct ssam_event_item - Struct for event queuing and completion. * @node: The node in the queue. * @rqid: The request ID of the event. + * @ops: Instance specific functions. + * @ops.free: Callback for freeing this event item. * @event: Actual event data. */ struct ssam_event_item { struct list_head node; u16 rqid; + struct { + void (*free)(struct ssam_event_item *event); + } ops; + struct ssam_event event; /* must be last */ }; @@ -273,4 +279,7 @@ int ssam_ctrl_notif_d0_entry(struct ssam_controller *ctrl); int ssam_controller_suspend(struct ssam_controller *ctrl); int ssam_controller_resume(struct ssam_controller *ctrl); +int ssam_event_item_cache_init(void); +void ssam_event_item_cache_destroy(void); + #endif /* _SURFACE_AGGREGATOR_CONTROLLER_H */ diff --git a/drivers/platform/surface/aggregator/core.c b/drivers/platform/surface/aggregator/core.c index 60d312f71436..37593234fb31 100644 --- a/drivers/platform/surface/aggregator/core.c +++ b/drivers/platform/surface/aggregator/core.c @@ -790,12 +790,23 @@ static int __init ssam_core_init(void) status = ssh_ctrl_packet_cache_init(); if (status) - return status; + goto err_cpkg; + + status = ssam_event_item_cache_init(); + if (status) + goto err_evitem; status = serdev_device_driver_register(&ssam_serial_hub); if (status) - ssh_ctrl_packet_cache_destroy(); + goto err_register; + return 0; + +err_register: + ssam_event_item_cache_destroy(); +err_evitem: + ssh_ctrl_packet_cache_destroy(); +err_cpkg: return status; } module_init(ssam_core_init); @@ -803,6 +814,7 @@ module_init(ssam_core_init); static void __exit ssam_core_exit(void) { serdev_device_driver_unregister(&ssam_serial_hub); + ssam_event_item_cache_destroy(); ssh_ctrl_packet_cache_destroy(); } module_exit(ssam_core_exit); -- cgit v1.2.3 From 0d21bb8560ef6bd09cab873120f940a939ad3aec Mon Sep 17 00:00:00 2001 From: Maximilian Luz Date: Mon, 21 Dec 2020 19:39:54 +0100 Subject: platform/surface: aggregator: Add trace points Add trace points to the Surface Aggregator subsystem core. These trace points can be used to track packets, requests, and allocations. They are further intended for debugging and testing/validation, specifically in combination with the error injection capabilities introduced in the subsequent commit. Signed-off-by: Maximilian Luz Reviewed-by: Hans de Goede Acked-by: Steven Rostedt (VMware) Link: https://lore.kernel.org/r/20201221183959.1186143-5-luzmaximilian@gmail.com Signed-off-by: Hans de Goede --- drivers/platform/surface/aggregator/Makefile | 3 + drivers/platform/surface/aggregator/controller.c | 5 + drivers/platform/surface/aggregator/core.c | 3 + .../platform/surface/aggregator/ssh_packet_layer.c | 26 +- .../surface/aggregator/ssh_request_layer.c | 18 + drivers/platform/surface/aggregator/trace.h | 601 +++++++++++++++++++++ 6 files changed, 655 insertions(+), 1 deletion(-) create mode 100644 drivers/platform/surface/aggregator/trace.h (limited to 'drivers/platform/surface') diff --git a/drivers/platform/surface/aggregator/Makefile b/drivers/platform/surface/aggregator/Makefile index faad18d4a7f2..b8b24c8ec310 100644 --- a/drivers/platform/surface/aggregator/Makefile +++ b/drivers/platform/surface/aggregator/Makefile @@ -1,6 +1,9 @@ # SPDX-License-Identifier: GPL-2.0+ # Copyright (C) 2019-2020 Maximilian Luz +# For include/trace/define_trace.h to include trace.h +CFLAGS_core.o = -I$(src) + obj-$(CONFIG_SURFACE_AGGREGATOR) += surface_aggregator.o surface_aggregator-objs := core.o diff --git a/drivers/platform/surface/aggregator/controller.c b/drivers/platform/surface/aggregator/controller.c index 775a4509bece..5bcb59ed579d 100644 --- a/drivers/platform/surface/aggregator/controller.c +++ b/drivers/platform/surface/aggregator/controller.c @@ -32,6 +32,8 @@ #include "ssh_msgb.h" #include "ssh_request_layer.h" +#include "trace.h" + /* -- Safe counters. -------------------------------------------------------- */ @@ -568,6 +570,7 @@ static void __ssam_event_item_free_generic(struct ssam_event_item *item) */ static void ssam_event_item_free(struct ssam_event_item *item) { + trace_ssam_event_item_free(item); item->ops.free(item); } @@ -603,6 +606,8 @@ static struct ssam_event_item *ssam_event_item_alloc(size_t len, gfp_t flags) } item->event.length = len; + + trace_ssam_event_item_alloc(item, len); return item; } diff --git a/drivers/platform/surface/aggregator/core.c b/drivers/platform/surface/aggregator/core.c index 37593234fb31..b6a9dea53592 100644 --- a/drivers/platform/surface/aggregator/core.c +++ b/drivers/platform/surface/aggregator/core.c @@ -24,6 +24,9 @@ #include #include "controller.h" +#define CREATE_TRACE_POINTS +#include "trace.h" + /* -- Static controller reference. ------------------------------------------ */ diff --git a/drivers/platform/surface/aggregator/ssh_packet_layer.c b/drivers/platform/surface/aggregator/ssh_packet_layer.c index 23c2e31e7d0e..c4f082e57372 100644 --- a/drivers/platform/surface/aggregator/ssh_packet_layer.c +++ b/drivers/platform/surface/aggregator/ssh_packet_layer.c @@ -26,6 +26,8 @@ #include "ssh_packet_layer.h" #include "ssh_parser.h" +#include "trace.h" + /* * To simplify reasoning about the code below, we define a few concepts. The * system below is similar to a state-machine for packets, however, there are @@ -228,6 +230,8 @@ static void __ssh_ptl_packet_release(struct kref *kref) { struct ssh_packet *p = container_of(kref, struct ssh_packet, refcnt); + trace_ssam_packet_release(p); + ptl_dbg_cond(p->ptl, "ptl: releasing packet %p\n", p); p->ops->release(p); } @@ -356,6 +360,7 @@ static int ssh_ctrl_packet_alloc(struct ssh_packet **packet, buffer->ptr = (u8 *)(*packet + 1); buffer->len = SSH_MSG_LEN_CTRL; + trace_ssam_ctrl_packet_alloc(*packet, buffer->len); return 0; } @@ -365,6 +370,7 @@ static int ssh_ctrl_packet_alloc(struct ssh_packet **packet, */ static void ssh_ctrl_packet_free(struct ssh_packet *p) { + trace_ssam_ctrl_packet_free(p); kmem_cache_free(ssh_ctrl_packet_cache, p); } @@ -398,7 +404,12 @@ static void ssh_packet_next_try(struct ssh_packet *p) lockdep_assert_held(&p->ptl->queue.lock); - p->priority = __SSH_PACKET_PRIORITY(base, try + 1); + /* + * Ensure that we write the priority in one go via WRITE_ONCE() so we + * can access it via READ_ONCE() for tracing. Note that other access + * is guarded by the queue lock, so no need to use READ_ONCE() there. + */ + WRITE_ONCE(p->priority, __SSH_PACKET_PRIORITY(base, try + 1)); } /* Must be called with queue lock held. */ @@ -560,6 +571,7 @@ static void __ssh_ptl_complete(struct ssh_packet *p, int status) { struct ssh_ptl *ptl = READ_ONCE(p->ptl); + trace_ssam_packet_complete(p, status); ptl_dbg_cond(ptl, "ptl: completing packet %p (status: %d)\n", p, status); if (p->ops->complete) @@ -1014,6 +1026,8 @@ int ssh_ptl_submit(struct ssh_ptl *ptl, struct ssh_packet *p) struct ssh_ptl *ptl_old; int status; + trace_ssam_packet_submit(p); + /* Validate packet fields. */ if (test_bit(SSH_PACKET_TY_FLUSH_BIT, &p->state)) { if (p->data.ptr || test_bit(SSH_PACKET_TY_SEQUENCED_BIT, &p->state)) @@ -1065,6 +1079,8 @@ static int __ssh_ptl_resubmit(struct ssh_packet *packet) lockdep_assert_held(&packet->ptl->pending.lock); + trace_ssam_packet_resubmit(packet); + spin_lock(&packet->ptl->queue.lock); /* Check if the packet is out of tries. */ @@ -1148,6 +1164,8 @@ void ssh_ptl_cancel(struct ssh_packet *p) if (test_and_set_bit(SSH_PACKET_SF_CANCELED_BIT, &p->state)) return; + trace_ssam_packet_cancel(p); + /* * Lock packet and commit with memory barrier. If this packet has * already been locked, it's going to be removed and completed by @@ -1202,6 +1220,8 @@ static void ssh_ptl_timeout_reap(struct work_struct *work) bool resub = false; int status; + trace_ssam_ptl_timeout_reap(atomic_read(&ptl->pending.count)); + /* * Mark reaper as "not pending". This is done before checking any * packets to avoid lost-update type problems. @@ -1224,6 +1244,8 @@ static void ssh_ptl_timeout_reap(struct work_struct *work) continue; } + trace_ssam_packet_timeout(p); + status = __ssh_ptl_resubmit(p); /* @@ -1416,6 +1438,8 @@ static size_t ssh_ptl_rx_eval(struct ssh_ptl *ptl, struct ssam_span *source) if (!frame) /* Not enough data. */ return aligned.ptr - source->ptr; + trace_ssam_rx_frame_received(frame); + switch (frame->type) { case SSH_FRAME_TYPE_ACK: ssh_ptl_acknowledge(ptl, frame->seq); diff --git a/drivers/platform/surface/aggregator/ssh_request_layer.c b/drivers/platform/surface/aggregator/ssh_request_layer.c index 66c839a995f3..b649d71840fd 100644 --- a/drivers/platform/surface/aggregator/ssh_request_layer.c +++ b/drivers/platform/surface/aggregator/ssh_request_layer.c @@ -22,6 +22,8 @@ #include "ssh_packet_layer.h" #include "ssh_request_layer.h" +#include "trace.h" + /* * SSH_RTL_REQUEST_TIMEOUT - Request timeout. * @@ -144,6 +146,8 @@ static void ssh_rtl_complete_with_status(struct ssh_request *rqst, int status) { struct ssh_rtl *rtl = ssh_request_rtl(rqst); + trace_ssam_request_complete(rqst, status); + /* rtl/ptl may not be set if we're canceling before submitting. */ rtl_dbg_cond(rtl, "rtl: completing request (rqid: %#06x, status: %d)\n", ssh_request_get_rqid_safe(rqst), status); @@ -157,6 +161,8 @@ static void ssh_rtl_complete_with_rsp(struct ssh_request *rqst, { struct ssh_rtl *rtl = ssh_request_rtl(rqst); + trace_ssam_request_complete(rqst, 0); + rtl_dbg(rtl, "rtl: completing request with response (rqid: %#06x)\n", ssh_request_get_rqid(rqst)); @@ -329,6 +335,8 @@ static void ssh_rtl_tx_work_fn(struct work_struct *work) */ int ssh_rtl_submit(struct ssh_rtl *rtl, struct ssh_request *rqst) { + trace_ssam_request_submit(rqst); + /* * Ensure that requests expecting a response are sequenced. If this * invariant ever changes, see the comment in ssh_rtl_complete() on what @@ -439,6 +447,8 @@ static void ssh_rtl_complete(struct ssh_rtl *rtl, struct ssh_request *p, *n; u16 rqid = get_unaligned_le16(&command->rqid); + trace_ssam_rx_response_received(command, command_data->len); + /* * Get request from pending based on request ID and mark it as response * received and locked. @@ -688,6 +698,8 @@ bool ssh_rtl_cancel(struct ssh_request *rqst, bool pending) if (test_and_set_bit(SSH_REQUEST_SF_CANCELED_BIT, &rqst->state)) return true; + trace_ssam_request_cancel(rqst); + if (pending) canceled = ssh_rtl_cancel_pending(rqst); else @@ -779,6 +791,8 @@ static void ssh_rtl_timeout_reap(struct work_struct *work) ktime_t timeout = rtl->rtx_timeout.timeout; ktime_t next = KTIME_MAX; + trace_ssam_rtl_timeout_reap(atomic_read(&rtl->pending.count)); + /* * Mark reaper as "not pending". This is done before checking any * requests to avoid lost-update type problems. @@ -822,6 +836,8 @@ static void ssh_rtl_timeout_reap(struct work_struct *work) /* Cancel and complete the request. */ list_for_each_entry_safe(r, n, &claimed, node) { + trace_ssam_request_timeout(r); + /* * At this point we've removed the packet from pending. This * means that we've obtained the last (only) reference of the @@ -849,6 +865,8 @@ static void ssh_rtl_timeout_reap(struct work_struct *work) static void ssh_rtl_rx_event(struct ssh_rtl *rtl, const struct ssh_command *cmd, const struct ssam_span *data) { + trace_ssam_rx_event_received(cmd, data->len); + rtl_dbg(rtl, "rtl: handling event (rqid: %#06x)\n", get_unaligned_le16(&cmd->rqid)); diff --git a/drivers/platform/surface/aggregator/trace.h b/drivers/platform/surface/aggregator/trace.h new file mode 100644 index 000000000000..dcca8007d876 --- /dev/null +++ b/drivers/platform/surface/aggregator/trace.h @@ -0,0 +1,601 @@ +/* SPDX-License-Identifier: GPL-2.0+ */ +/* + * Trace points for SSAM/SSH. + * + * Copyright (C) 2020 Maximilian Luz + */ + +#undef TRACE_SYSTEM +#define TRACE_SYSTEM surface_aggregator + +#if !defined(_SURFACE_AGGREGATOR_TRACE_H) || defined(TRACE_HEADER_MULTI_READ) +#define _SURFACE_AGGREGATOR_TRACE_H + +#include + +#include +#include + +TRACE_DEFINE_ENUM(SSH_FRAME_TYPE_DATA_SEQ); +TRACE_DEFINE_ENUM(SSH_FRAME_TYPE_DATA_NSQ); +TRACE_DEFINE_ENUM(SSH_FRAME_TYPE_ACK); +TRACE_DEFINE_ENUM(SSH_FRAME_TYPE_NAK); + +TRACE_DEFINE_ENUM(SSH_PACKET_SF_LOCKED_BIT); +TRACE_DEFINE_ENUM(SSH_PACKET_SF_QUEUED_BIT); +TRACE_DEFINE_ENUM(SSH_PACKET_SF_PENDING_BIT); +TRACE_DEFINE_ENUM(SSH_PACKET_SF_TRANSMITTING_BIT); +TRACE_DEFINE_ENUM(SSH_PACKET_SF_TRANSMITTED_BIT); +TRACE_DEFINE_ENUM(SSH_PACKET_SF_ACKED_BIT); +TRACE_DEFINE_ENUM(SSH_PACKET_SF_CANCELED_BIT); +TRACE_DEFINE_ENUM(SSH_PACKET_SF_COMPLETED_BIT); + +TRACE_DEFINE_ENUM(SSH_PACKET_TY_FLUSH_BIT); +TRACE_DEFINE_ENUM(SSH_PACKET_TY_SEQUENCED_BIT); +TRACE_DEFINE_ENUM(SSH_PACKET_TY_BLOCKING_BIT); + +TRACE_DEFINE_ENUM(SSH_PACKET_FLAGS_SF_MASK); +TRACE_DEFINE_ENUM(SSH_PACKET_FLAGS_TY_MASK); + +TRACE_DEFINE_ENUM(SSH_REQUEST_SF_LOCKED_BIT); +TRACE_DEFINE_ENUM(SSH_REQUEST_SF_QUEUED_BIT); +TRACE_DEFINE_ENUM(SSH_REQUEST_SF_PENDING_BIT); +TRACE_DEFINE_ENUM(SSH_REQUEST_SF_TRANSMITTING_BIT); +TRACE_DEFINE_ENUM(SSH_REQUEST_SF_TRANSMITTED_BIT); +TRACE_DEFINE_ENUM(SSH_REQUEST_SF_RSPRCVD_BIT); +TRACE_DEFINE_ENUM(SSH_REQUEST_SF_CANCELED_BIT); +TRACE_DEFINE_ENUM(SSH_REQUEST_SF_COMPLETED_BIT); + +TRACE_DEFINE_ENUM(SSH_REQUEST_TY_FLUSH_BIT); +TRACE_DEFINE_ENUM(SSH_REQUEST_TY_HAS_RESPONSE_BIT); + +TRACE_DEFINE_ENUM(SSH_REQUEST_FLAGS_SF_MASK); +TRACE_DEFINE_ENUM(SSH_REQUEST_FLAGS_TY_MASK); + +TRACE_DEFINE_ENUM(SSAM_SSH_TC_SAM); +TRACE_DEFINE_ENUM(SSAM_SSH_TC_BAT); +TRACE_DEFINE_ENUM(SSAM_SSH_TC_TMP); +TRACE_DEFINE_ENUM(SSAM_SSH_TC_PMC); +TRACE_DEFINE_ENUM(SSAM_SSH_TC_FAN); +TRACE_DEFINE_ENUM(SSAM_SSH_TC_PoM); +TRACE_DEFINE_ENUM(SSAM_SSH_TC_DBG); +TRACE_DEFINE_ENUM(SSAM_SSH_TC_KBD); +TRACE_DEFINE_ENUM(SSAM_SSH_TC_FWU); +TRACE_DEFINE_ENUM(SSAM_SSH_TC_UNI); +TRACE_DEFINE_ENUM(SSAM_SSH_TC_LPC); +TRACE_DEFINE_ENUM(SSAM_SSH_TC_TCL); +TRACE_DEFINE_ENUM(SSAM_SSH_TC_SFL); +TRACE_DEFINE_ENUM(SSAM_SSH_TC_KIP); +TRACE_DEFINE_ENUM(SSAM_SSH_TC_EXT); +TRACE_DEFINE_ENUM(SSAM_SSH_TC_BLD); +TRACE_DEFINE_ENUM(SSAM_SSH_TC_BAS); +TRACE_DEFINE_ENUM(SSAM_SSH_TC_SEN); +TRACE_DEFINE_ENUM(SSAM_SSH_TC_SRQ); +TRACE_DEFINE_ENUM(SSAM_SSH_TC_MCU); +TRACE_DEFINE_ENUM(SSAM_SSH_TC_HID); +TRACE_DEFINE_ENUM(SSAM_SSH_TC_TCH); +TRACE_DEFINE_ENUM(SSAM_SSH_TC_BKL); +TRACE_DEFINE_ENUM(SSAM_SSH_TC_TAM); +TRACE_DEFINE_ENUM(SSAM_SSH_TC_ACC); +TRACE_DEFINE_ENUM(SSAM_SSH_TC_UFI); +TRACE_DEFINE_ENUM(SSAM_SSH_TC_USC); +TRACE_DEFINE_ENUM(SSAM_SSH_TC_PEN); +TRACE_DEFINE_ENUM(SSAM_SSH_TC_VID); +TRACE_DEFINE_ENUM(SSAM_SSH_TC_AUD); +TRACE_DEFINE_ENUM(SSAM_SSH_TC_SMC); +TRACE_DEFINE_ENUM(SSAM_SSH_TC_KPD); +TRACE_DEFINE_ENUM(SSAM_SSH_TC_REG); + +#define SSAM_PTR_UID_LEN 9 +#define SSAM_U8_FIELD_NOT_APPLICABLE ((u16)-1) +#define SSAM_SEQ_NOT_APPLICABLE ((u16)-1) +#define SSAM_RQID_NOT_APPLICABLE ((u32)-1) +#define SSAM_SSH_TC_NOT_APPLICABLE 0 + +#ifndef _SURFACE_AGGREGATOR_TRACE_HELPERS +#define _SURFACE_AGGREGATOR_TRACE_HELPERS + +/** + * ssam_trace_ptr_uid() - Convert the pointer to a non-pointer UID string. + * @ptr: The pointer to convert. + * @uid_str: A buffer of length SSAM_PTR_UID_LEN where the UID will be stored. + * + * Converts the given pointer into a UID string that is safe to be shared + * with userspace and logs, i.e. doesn't give away the real memory location. + */ +static inline void ssam_trace_ptr_uid(const void *ptr, char *uid_str) +{ + char buf[2 * sizeof(void *) + 1]; + + BUILD_BUG_ON(ARRAY_SIZE(buf) < SSAM_PTR_UID_LEN); + + snprintf(buf, ARRAY_SIZE(buf), "%p", ptr); + memcpy(uid_str, &buf[ARRAY_SIZE(buf) - SSAM_PTR_UID_LEN], + SSAM_PTR_UID_LEN); +} + +/** + * ssam_trace_get_packet_seq() - Read the packet's sequence ID. + * @p: The packet. + * + * Return: Returns the packet's sequence ID (SEQ) field if present, or + * %SSAM_SEQ_NOT_APPLICABLE if not (e.g. flush packet). + */ +static inline u16 ssam_trace_get_packet_seq(const struct ssh_packet *p) +{ + if (!p->data.ptr || p->data.len < SSH_MESSAGE_LENGTH(0)) + return SSAM_SEQ_NOT_APPLICABLE; + + return p->data.ptr[SSH_MSGOFFSET_FRAME(seq)]; +} + +/** + * ssam_trace_get_request_id() - Read the packet's request ID. + * @p: The packet. + * + * Return: Returns the packet's request ID (RQID) field if the packet + * represents a request with command data, or %SSAM_RQID_NOT_APPLICABLE if not + * (e.g. flush request, control packet). + */ +static inline u32 ssam_trace_get_request_id(const struct ssh_packet *p) +{ + if (!p->data.ptr || p->data.len < SSH_COMMAND_MESSAGE_LENGTH(0)) + return SSAM_RQID_NOT_APPLICABLE; + + return get_unaligned_le16(&p->data.ptr[SSH_MSGOFFSET_COMMAND(rqid)]); +} + +/** + * ssam_trace_get_request_tc() - Read the packet's request target category. + * @p: The packet. + * + * Return: Returns the packet's request target category (TC) field if the + * packet represents a request with command data, or %SSAM_TC_NOT_APPLICABLE + * if not (e.g. flush request, control packet). + */ +static inline u32 ssam_trace_get_request_tc(const struct ssh_packet *p) +{ + if (!p->data.ptr || p->data.len < SSH_COMMAND_MESSAGE_LENGTH(0)) + return SSAM_SSH_TC_NOT_APPLICABLE; + + return get_unaligned_le16(&p->data.ptr[SSH_MSGOFFSET_COMMAND(tc)]); +} + +#endif /* _SURFACE_AGGREGATOR_TRACE_HELPERS */ + +#define ssam_trace_get_command_field_u8(packet, field) \ + ((!(packet) || (packet)->data.len < SSH_COMMAND_MESSAGE_LENGTH(0)) \ + ? 0 : (packet)->data.ptr[SSH_MSGOFFSET_COMMAND(field)]) + +#define ssam_show_generic_u8_field(value) \ + __print_symbolic(value, \ + { SSAM_U8_FIELD_NOT_APPLICABLE, "N/A" } \ + ) + +#define ssam_show_frame_type(ty) \ + __print_symbolic(ty, \ + { SSH_FRAME_TYPE_DATA_SEQ, "DSEQ" }, \ + { SSH_FRAME_TYPE_DATA_NSQ, "DNSQ" }, \ + { SSH_FRAME_TYPE_ACK, "ACK" }, \ + { SSH_FRAME_TYPE_NAK, "NAK" } \ + ) + +#define ssam_show_packet_type(type) \ + __print_flags(flags & SSH_PACKET_FLAGS_TY_MASK, "", \ + { BIT(SSH_PACKET_TY_FLUSH_BIT), "F" }, \ + { BIT(SSH_PACKET_TY_SEQUENCED_BIT), "S" }, \ + { BIT(SSH_PACKET_TY_BLOCKING_BIT), "B" } \ + ) + +#define ssam_show_packet_state(state) \ + __print_flags(flags & SSH_PACKET_FLAGS_SF_MASK, "", \ + { BIT(SSH_PACKET_SF_LOCKED_BIT), "L" }, \ + { BIT(SSH_PACKET_SF_QUEUED_BIT), "Q" }, \ + { BIT(SSH_PACKET_SF_PENDING_BIT), "P" }, \ + { BIT(SSH_PACKET_SF_TRANSMITTING_BIT), "S" }, \ + { BIT(SSH_PACKET_SF_TRANSMITTED_BIT), "T" }, \ + { BIT(SSH_PACKET_SF_ACKED_BIT), "A" }, \ + { BIT(SSH_PACKET_SF_CANCELED_BIT), "C" }, \ + { BIT(SSH_PACKET_SF_COMPLETED_BIT), "F" } \ + ) + +#define ssam_show_packet_seq(seq) \ + __print_symbolic(seq, \ + { SSAM_SEQ_NOT_APPLICABLE, "N/A" } \ + ) + +#define ssam_show_request_type(flags) \ + __print_flags((flags) & SSH_REQUEST_FLAGS_TY_MASK, "", \ + { BIT(SSH_REQUEST_TY_FLUSH_BIT), "F" }, \ + { BIT(SSH_REQUEST_TY_HAS_RESPONSE_BIT), "R" } \ + ) + +#define ssam_show_request_state(flags) \ + __print_flags((flags) & SSH_REQUEST_FLAGS_SF_MASK, "", \ + { BIT(SSH_REQUEST_SF_LOCKED_BIT), "L" }, \ + { BIT(SSH_REQUEST_SF_QUEUED_BIT), "Q" }, \ + { BIT(SSH_REQUEST_SF_PENDING_BIT), "P" }, \ + { BIT(SSH_REQUEST_SF_TRANSMITTING_BIT), "S" }, \ + { BIT(SSH_REQUEST_SF_TRANSMITTED_BIT), "T" }, \ + { BIT(SSH_REQUEST_SF_RSPRCVD_BIT), "A" }, \ + { BIT(SSH_REQUEST_SF_CANCELED_BIT), "C" }, \ + { BIT(SSH_REQUEST_SF_COMPLETED_BIT), "F" } \ + ) + +#define ssam_show_request_id(rqid) \ + __print_symbolic(rqid, \ + { SSAM_RQID_NOT_APPLICABLE, "N/A" } \ + ) + +#define ssam_show_ssh_tc(rqid) \ + __print_symbolic(rqid, \ + { SSAM_SSH_TC_NOT_APPLICABLE, "N/A" }, \ + { SSAM_SSH_TC_SAM, "SAM" }, \ + { SSAM_SSH_TC_BAT, "BAT" }, \ + { SSAM_SSH_TC_TMP, "TMP" }, \ + { SSAM_SSH_TC_PMC, "PMC" }, \ + { SSAM_SSH_TC_FAN, "FAN" }, \ + { SSAM_SSH_TC_PoM, "PoM" }, \ + { SSAM_SSH_TC_DBG, "DBG" }, \ + { SSAM_SSH_TC_KBD, "KBD" }, \ + { SSAM_SSH_TC_FWU, "FWU" }, \ + { SSAM_SSH_TC_UNI, "UNI" }, \ + { SSAM_SSH_TC_LPC, "LPC" }, \ + { SSAM_SSH_TC_TCL, "TCL" }, \ + { SSAM_SSH_TC_SFL, "SFL" }, \ + { SSAM_SSH_TC_KIP, "KIP" }, \ + { SSAM_SSH_TC_EXT, "EXT" }, \ + { SSAM_SSH_TC_BLD, "BLD" }, \ + { SSAM_SSH_TC_BAS, "BAS" }, \ + { SSAM_SSH_TC_SEN, "SEN" }, \ + { SSAM_SSH_TC_SRQ, "SRQ" }, \ + { SSAM_SSH_TC_MCU, "MCU" }, \ + { SSAM_SSH_TC_HID, "HID" }, \ + { SSAM_SSH_TC_TCH, "TCH" }, \ + { SSAM_SSH_TC_BKL, "BKL" }, \ + { SSAM_SSH_TC_TAM, "TAM" }, \ + { SSAM_SSH_TC_ACC, "ACC" }, \ + { SSAM_SSH_TC_UFI, "UFI" }, \ + { SSAM_SSH_TC_USC, "USC" }, \ + { SSAM_SSH_TC_PEN, "PEN" }, \ + { SSAM_SSH_TC_VID, "VID" }, \ + { SSAM_SSH_TC_AUD, "AUD" }, \ + { SSAM_SSH_TC_SMC, "SMC" }, \ + { SSAM_SSH_TC_KPD, "KPD" }, \ + { SSAM_SSH_TC_REG, "REG" } \ + ) + +DECLARE_EVENT_CLASS(ssam_frame_class, + TP_PROTO(const struct ssh_frame *frame), + + TP_ARGS(frame), + + TP_STRUCT__entry( + __field(u8, type) + __field(u8, seq) + __field(u16, len) + ), + + TP_fast_assign( + __entry->type = frame->type; + __entry->seq = frame->seq; + __entry->len = get_unaligned_le16(&frame->len); + ), + + TP_printk("ty=%s, seq=%#04x, len=%u", + ssam_show_frame_type(__entry->type), + __entry->seq, + __entry->len + ) +); + +#define DEFINE_SSAM_FRAME_EVENT(name) \ + DEFINE_EVENT(ssam_frame_class, ssam_##name, \ + TP_PROTO(const struct ssh_frame *frame), \ + TP_ARGS(frame) \ + ) + +DECLARE_EVENT_CLASS(ssam_command_class, + TP_PROTO(const struct ssh_command *cmd, u16 len), + + TP_ARGS(cmd, len), + + TP_STRUCT__entry( + __field(u16, rqid) + __field(u16, len) + __field(u8, tc) + __field(u8, cid) + __field(u8, iid) + ), + + TP_fast_assign( + __entry->rqid = get_unaligned_le16(&cmd->rqid); + __entry->tc = cmd->tc; + __entry->cid = cmd->cid; + __entry->iid = cmd->iid; + __entry->len = len; + ), + + TP_printk("rqid=%#06x, tc=%s, cid=%#04x, iid=%#04x, len=%u", + __entry->rqid, + ssam_show_ssh_tc(__entry->tc), + __entry->cid, + __entry->iid, + __entry->len + ) +); + +#define DEFINE_SSAM_COMMAND_EVENT(name) \ + DEFINE_EVENT(ssam_command_class, ssam_##name, \ + TP_PROTO(const struct ssh_command *cmd, u16 len), \ + TP_ARGS(cmd, len) \ + ) + +DECLARE_EVENT_CLASS(ssam_packet_class, + TP_PROTO(const struct ssh_packet *packet), + + TP_ARGS(packet), + + TP_STRUCT__entry( + __field(unsigned long, state) + __array(char, uid, SSAM_PTR_UID_LEN) + __field(u8, priority) + __field(u16, length) + __field(u16, seq) + ), + + TP_fast_assign( + __entry->state = READ_ONCE(packet->state); + ssam_trace_ptr_uid(packet, __entry->uid); + __entry->priority = READ_ONCE(packet->priority); + __entry->length = packet->data.len; + __entry->seq = ssam_trace_get_packet_seq(packet); + ), + + TP_printk("uid=%s, seq=%s, ty=%s, pri=%#04x, len=%u, sta=%s", + __entry->uid, + ssam_show_packet_seq(__entry->seq), + ssam_show_packet_type(__entry->state), + __entry->priority, + __entry->length, + ssam_show_packet_state(__entry->state) + ) +); + +#define DEFINE_SSAM_PACKET_EVENT(name) \ + DEFINE_EVENT(ssam_packet_class, ssam_##name, \ + TP_PROTO(const struct ssh_packet *packet), \ + TP_ARGS(packet) \ + ) + +DECLARE_EVENT_CLASS(ssam_packet_status_class, + TP_PROTO(const struct ssh_packet *packet, int status), + + TP_ARGS(packet, status), + + TP_STRUCT__entry( + __field(unsigned long, state) + __field(int, status) + __array(char, uid, SSAM_PTR_UID_LEN) + __field(u8, priority) + __field(u16, length) + __field(u16, seq) + ), + + TP_fast_assign( + __entry->state = READ_ONCE(packet->state); + __entry->status = status; + ssam_trace_ptr_uid(packet, __entry->uid); + __entry->priority = READ_ONCE(packet->priority); + __entry->length = packet->data.len; + __entry->seq = ssam_trace_get_packet_seq(packet); + ), + + TP_printk("uid=%s, seq=%s, ty=%s, pri=%#04x, len=%u, sta=%s, status=%d", + __entry->uid, + ssam_show_packet_seq(__entry->seq), + ssam_show_packet_type(__entry->state), + __entry->priority, + __entry->length, + ssam_show_packet_state(__entry->state), + __entry->status + ) +); + +#define DEFINE_SSAM_PACKET_STATUS_EVENT(name) \ + DEFINE_EVENT(ssam_packet_status_class, ssam_##name, \ + TP_PROTO(const struct ssh_packet *packet, int status), \ + TP_ARGS(packet, status) \ + ) + +DECLARE_EVENT_CLASS(ssam_request_class, + TP_PROTO(const struct ssh_request *request), + + TP_ARGS(request), + + TP_STRUCT__entry( + __field(unsigned long, state) + __field(u32, rqid) + __array(char, uid, SSAM_PTR_UID_LEN) + __field(u8, tc) + __field(u16, cid) + __field(u16, iid) + ), + + TP_fast_assign( + const struct ssh_packet *p = &request->packet; + + /* Use packet for UID so we can match requests to packets. */ + __entry->state = READ_ONCE(request->state); + __entry->rqid = ssam_trace_get_request_id(p); + ssam_trace_ptr_uid(p, __entry->uid); + __entry->tc = ssam_trace_get_request_tc(p); + __entry->cid = ssam_trace_get_command_field_u8(p, cid); + __entry->iid = ssam_trace_get_command_field_u8(p, iid); + ), + + TP_printk("uid=%s, rqid=%s, ty=%s, sta=%s, tc=%s, cid=%s, iid=%s", + __entry->uid, + ssam_show_request_id(__entry->rqid), + ssam_show_request_type(__entry->state), + ssam_show_request_state(__entry->state), + ssam_show_ssh_tc(__entry->tc), + ssam_show_generic_u8_field(__entry->cid), + ssam_show_generic_u8_field(__entry->iid) + ) +); + +#define DEFINE_SSAM_REQUEST_EVENT(name) \ + DEFINE_EVENT(ssam_request_class, ssam_##name, \ + TP_PROTO(const struct ssh_request *request), \ + TP_ARGS(request) \ + ) + +DECLARE_EVENT_CLASS(ssam_request_status_class, + TP_PROTO(const struct ssh_request *request, int status), + + TP_ARGS(request, status), + + TP_STRUCT__entry( + __field(unsigned long, state) + __field(u32, rqid) + __field(int, status) + __array(char, uid, SSAM_PTR_UID_LEN) + __field(u8, tc) + __field(u16, cid) + __field(u16, iid) + ), + + TP_fast_assign( + const struct ssh_packet *p = &request->packet; + + /* Use packet for UID so we can match requests to packets. */ + __entry->state = READ_ONCE(request->state); + __entry->rqid = ssam_trace_get_request_id(p); + __entry->status = status; + ssam_trace_ptr_uid(p, __entry->uid); + __entry->tc = ssam_trace_get_request_tc(p); + __entry->cid = ssam_trace_get_command_field_u8(p, cid); + __entry->iid = ssam_trace_get_command_field_u8(p, iid); + ), + + TP_printk("uid=%s, rqid=%s, ty=%s, sta=%s, tc=%s, cid=%s, iid=%s, status=%d", + __entry->uid, + ssam_show_request_id(__entry->rqid), + ssam_show_request_type(__entry->state), + ssam_show_request_state(__entry->state), + ssam_show_ssh_tc(__entry->tc), + ssam_show_generic_u8_field(__entry->cid), + ssam_show_generic_u8_field(__entry->iid), + __entry->status + ) +); + +#define DEFINE_SSAM_REQUEST_STATUS_EVENT(name) \ + DEFINE_EVENT(ssam_request_status_class, ssam_##name, \ + TP_PROTO(const struct ssh_request *request, int status),\ + TP_ARGS(request, status) \ + ) + +DECLARE_EVENT_CLASS(ssam_alloc_class, + TP_PROTO(void *ptr, size_t len), + + TP_ARGS(ptr, len), + + TP_STRUCT__entry( + __field(size_t, len) + __array(char, uid, SSAM_PTR_UID_LEN) + ), + + TP_fast_assign( + __entry->len = len; + ssam_trace_ptr_uid(ptr, __entry->uid); + ), + + TP_printk("uid=%s, len=%zu", __entry->uid, __entry->len) +); + +#define DEFINE_SSAM_ALLOC_EVENT(name) \ + DEFINE_EVENT(ssam_alloc_class, ssam_##name, \ + TP_PROTO(void *ptr, size_t len), \ + TP_ARGS(ptr, len) \ + ) + +DECLARE_EVENT_CLASS(ssam_free_class, + TP_PROTO(void *ptr), + + TP_ARGS(ptr), + + TP_STRUCT__entry( + __array(char, uid, SSAM_PTR_UID_LEN) + ), + + TP_fast_assign( + ssam_trace_ptr_uid(ptr, __entry->uid); + ), + + TP_printk("uid=%s", __entry->uid) +); + +#define DEFINE_SSAM_FREE_EVENT(name) \ + DEFINE_EVENT(ssam_free_class, ssam_##name, \ + TP_PROTO(void *ptr), \ + TP_ARGS(ptr) \ + ) + +DECLARE_EVENT_CLASS(ssam_pending_class, + TP_PROTO(unsigned int pending), + + TP_ARGS(pending), + + TP_STRUCT__entry( + __field(unsigned int, pending) + ), + + TP_fast_assign( + __entry->pending = pending; + ), + + TP_printk("pending=%u", __entry->pending) +); + +#define DEFINE_SSAM_PENDING_EVENT(name) \ + DEFINE_EVENT(ssam_pending_class, ssam_##name, \ + TP_PROTO(unsigned int pending), \ + TP_ARGS(pending) \ + ) + +DEFINE_SSAM_FRAME_EVENT(rx_frame_received); +DEFINE_SSAM_COMMAND_EVENT(rx_response_received); +DEFINE_SSAM_COMMAND_EVENT(rx_event_received); + +DEFINE_SSAM_PACKET_EVENT(packet_release); +DEFINE_SSAM_PACKET_EVENT(packet_submit); +DEFINE_SSAM_PACKET_EVENT(packet_resubmit); +DEFINE_SSAM_PACKET_EVENT(packet_timeout); +DEFINE_SSAM_PACKET_EVENT(packet_cancel); +DEFINE_SSAM_PACKET_STATUS_EVENT(packet_complete); +DEFINE_SSAM_PENDING_EVENT(ptl_timeout_reap); + +DEFINE_SSAM_REQUEST_EVENT(request_submit); +DEFINE_SSAM_REQUEST_EVENT(request_timeout); +DEFINE_SSAM_REQUEST_EVENT(request_cancel); +DEFINE_SSAM_REQUEST_STATUS_EVENT(request_complete); +DEFINE_SSAM_PENDING_EVENT(rtl_timeout_reap); + +DEFINE_SSAM_ALLOC_EVENT(ctrl_packet_alloc); +DEFINE_SSAM_FREE_EVENT(ctrl_packet_free); + +DEFINE_SSAM_ALLOC_EVENT(event_item_alloc); +DEFINE_SSAM_FREE_EVENT(event_item_free); + +#endif /* _SURFACE_AGGREGATOR_TRACE_H */ + +/* This part must be outside protection */ +#undef TRACE_INCLUDE_PATH +#undef TRACE_INCLUDE_FILE + +#define TRACE_INCLUDE_PATH . +#define TRACE_INCLUDE_FILE trace + +#include -- cgit v1.2.3 From 02be44f6b5a9e4ff1215d337ac4d2a6fbafc7874 Mon Sep 17 00:00:00 2001 From: Maximilian Luz Date: Mon, 21 Dec 2020 19:39:55 +0100 Subject: platform/surface: aggregator: Add error injection capabilities This commit adds error injection hooks to the Surface Serial Hub communication protocol implementation, to: - simulate simple serial transmission errors, - drop packets, requests, and responses, simulating communication failures and potentially trigger retransmission timeouts, as well as - inject invalid data into submitted and received packets. Together with the trace points introduced in the previous commit, these facilities are intended to aid in testing, validation, and debugging of the Surface Aggregator communication layer. Signed-off-by: Maximilian Luz Reviewed-by: Hans de Goede Acked-by: Steven Rostedt (VMware) Link: https://lore.kernel.org/r/20201221183959.1186143-6-luzmaximilian@gmail.com Signed-off-by: Hans de Goede --- drivers/platform/surface/aggregator/Kconfig | 14 + .../platform/surface/aggregator/ssh_packet_layer.c | 296 ++++++++++++++++++++- .../surface/aggregator/ssh_request_layer.c | 35 +++ drivers/platform/surface/aggregator/trace.h | 31 +++ 4 files changed, 375 insertions(+), 1 deletion(-) (limited to 'drivers/platform/surface') diff --git a/drivers/platform/surface/aggregator/Kconfig b/drivers/platform/surface/aggregator/Kconfig index e9f4ad96e40a..e417bac67088 100644 --- a/drivers/platform/surface/aggregator/Kconfig +++ b/drivers/platform/surface/aggregator/Kconfig @@ -40,3 +40,17 @@ menuconfig SURFACE_AGGREGATOR Choose m if you want to build the SAM subsystem core and SSH driver as module, y if you want to build it into the kernel and n if you don't want it at all. + +config SURFACE_AGGREGATOR_ERROR_INJECTION + bool "Surface System Aggregator Module Error Injection Capabilities" + depends on SURFACE_AGGREGATOR + depends on FUNCTION_ERROR_INJECTION + help + Provides error-injection capabilities for the Surface System + Aggregator Module subsystem and Surface Serial Hub driver. + + Specifically, exports error injection hooks to be used with the + kernel's function error injection capabilities to simulate underlying + transport and communication problems, such as invalid data sent to or + received from the EC, dropped data, and communication timeouts. + Intended for development and debugging. diff --git a/drivers/platform/surface/aggregator/ssh_packet_layer.c b/drivers/platform/surface/aggregator/ssh_packet_layer.c index c4f082e57372..74f0faaa2b27 100644 --- a/drivers/platform/surface/aggregator/ssh_packet_layer.c +++ b/drivers/platform/surface/aggregator/ssh_packet_layer.c @@ -7,6 +7,7 @@ #include #include +#include #include #include #include @@ -226,6 +227,286 @@ */ #define SSH_PTL_RX_FIFO_LEN 4096 +#ifdef CONFIG_SURFACE_AGGREGATOR_ERROR_INJECTION + +/** + * ssh_ptl_should_drop_ack_packet() - Error injection hook to drop ACK packets. + * + * Useful to test detection and handling of automated re-transmits by the EC. + * Specifically of packets that the EC considers not-ACKed but the driver + * already considers ACKed (due to dropped ACK). In this case, the EC + * re-transmits the packet-to-be-ACKed and the driver should detect it as + * duplicate/already handled. Note that the driver should still send an ACK + * for the re-transmitted packet. + */ +static noinline bool ssh_ptl_should_drop_ack_packet(void) +{ + return false; +} +ALLOW_ERROR_INJECTION(ssh_ptl_should_drop_ack_packet, TRUE); + +/** + * ssh_ptl_should_drop_nak_packet() - Error injection hook to drop NAK packets. + * + * Useful to test/force automated (timeout-based) re-transmit by the EC. + * Specifically, packets that have not reached the driver completely/with valid + * checksums. Only useful in combination with receival of (injected) bad data. + */ +static noinline bool ssh_ptl_should_drop_nak_packet(void) +{ + return false; +} +ALLOW_ERROR_INJECTION(ssh_ptl_should_drop_nak_packet, TRUE); + +/** + * ssh_ptl_should_drop_dsq_packet() - Error injection hook to drop sequenced + * data packet. + * + * Useful to test re-transmit timeout of the driver. If the data packet has not + * been ACKed after a certain time, the driver should re-transmit the packet up + * to limited number of times defined in SSH_PTL_MAX_PACKET_TRIES. + */ +static noinline bool ssh_ptl_should_drop_dsq_packet(void) +{ + return false; +} +ALLOW_ERROR_INJECTION(ssh_ptl_should_drop_dsq_packet, TRUE); + +/** + * ssh_ptl_should_fail_write() - Error injection hook to make + * serdev_device_write() fail. + * + * Hook to simulate errors in serdev_device_write when transmitting packets. + */ +static noinline int ssh_ptl_should_fail_write(void) +{ + return 0; +} +ALLOW_ERROR_INJECTION(ssh_ptl_should_fail_write, ERRNO); + +/** + * ssh_ptl_should_corrupt_tx_data() - Error injection hook to simulate invalid + * data being sent to the EC. + * + * Hook to simulate corrupt/invalid data being sent from host (driver) to EC. + * Causes the packet data to be actively corrupted by overwriting it with + * pre-defined values, such that it becomes invalid, causing the EC to respond + * with a NAK packet. Useful to test handling of NAK packets received by the + * driver. + */ +static noinline bool ssh_ptl_should_corrupt_tx_data(void) +{ + return false; +} +ALLOW_ERROR_INJECTION(ssh_ptl_should_corrupt_tx_data, TRUE); + +/** + * ssh_ptl_should_corrupt_rx_syn() - Error injection hook to simulate invalid + * data being sent by the EC. + * + * Hook to simulate invalid SYN bytes, i.e. an invalid start of messages and + * test handling thereof in the driver. + */ +static noinline bool ssh_ptl_should_corrupt_rx_syn(void) +{ + return false; +} +ALLOW_ERROR_INJECTION(ssh_ptl_should_corrupt_rx_syn, TRUE); + +/** + * ssh_ptl_should_corrupt_rx_data() - Error injection hook to simulate invalid + * data being sent by the EC. + * + * Hook to simulate invalid data/checksum of the message frame and test handling + * thereof in the driver. + */ +static noinline bool ssh_ptl_should_corrupt_rx_data(void) +{ + return false; +} +ALLOW_ERROR_INJECTION(ssh_ptl_should_corrupt_rx_data, TRUE); + +static bool __ssh_ptl_should_drop_ack_packet(struct ssh_packet *packet) +{ + if (likely(!ssh_ptl_should_drop_ack_packet())) + return false; + + trace_ssam_ei_tx_drop_ack_packet(packet); + ptl_info(packet->ptl, "packet error injection: dropping ACK packet %p\n", + packet); + + return true; +} + +static bool __ssh_ptl_should_drop_nak_packet(struct ssh_packet *packet) +{ + if (likely(!ssh_ptl_should_drop_nak_packet())) + return false; + + trace_ssam_ei_tx_drop_nak_packet(packet); + ptl_info(packet->ptl, "packet error injection: dropping NAK packet %p\n", + packet); + + return true; +} + +static bool __ssh_ptl_should_drop_dsq_packet(struct ssh_packet *packet) +{ + if (likely(!ssh_ptl_should_drop_dsq_packet())) + return false; + + trace_ssam_ei_tx_drop_dsq_packet(packet); + ptl_info(packet->ptl, + "packet error injection: dropping sequenced data packet %p\n", + packet); + + return true; +} + +static bool ssh_ptl_should_drop_packet(struct ssh_packet *packet) +{ + /* Ignore packets that don't carry any data (i.e. flush). */ + if (!packet->data.ptr || !packet->data.len) + return false; + + switch (packet->data.ptr[SSH_MSGOFFSET_FRAME(type)]) { + case SSH_FRAME_TYPE_ACK: + return __ssh_ptl_should_drop_ack_packet(packet); + + case SSH_FRAME_TYPE_NAK: + return __ssh_ptl_should_drop_nak_packet(packet); + + case SSH_FRAME_TYPE_DATA_SEQ: + return __ssh_ptl_should_drop_dsq_packet(packet); + + default: + return false; + } +} + +static int ssh_ptl_write_buf(struct ssh_ptl *ptl, struct ssh_packet *packet, + const unsigned char *buf, size_t count) +{ + int status; + + status = ssh_ptl_should_fail_write(); + if (unlikely(status)) { + trace_ssam_ei_tx_fail_write(packet, status); + ptl_info(packet->ptl, + "packet error injection: simulating transmit error %d, packet %p\n", + status, packet); + + return status; + } + + return serdev_device_write_buf(ptl->serdev, buf, count); +} + +static void ssh_ptl_tx_inject_invalid_data(struct ssh_packet *packet) +{ + /* Ignore packets that don't carry any data (i.e. flush). */ + if (!packet->data.ptr || !packet->data.len) + return; + + /* Only allow sequenced data packets to be modified. */ + if (packet->data.ptr[SSH_MSGOFFSET_FRAME(type)] != SSH_FRAME_TYPE_DATA_SEQ) + return; + + if (likely(!ssh_ptl_should_corrupt_tx_data())) + return; + + trace_ssam_ei_tx_corrupt_data(packet); + ptl_info(packet->ptl, + "packet error injection: simulating invalid transmit data on packet %p\n", + packet); + + /* + * NB: The value 0xb3 has been chosen more or less randomly so that it + * doesn't have any (major) overlap with the SYN bytes (aa 55) and is + * non-trivial (i.e. non-zero, non-0xff). + */ + memset(packet->data.ptr, 0xb3, packet->data.len); +} + +static void ssh_ptl_rx_inject_invalid_syn(struct ssh_ptl *ptl, + struct ssam_span *data) +{ + struct ssam_span frame; + + /* Check if there actually is something to corrupt. */ + if (!sshp_find_syn(data, &frame)) + return; + + if (likely(!ssh_ptl_should_corrupt_rx_syn())) + return; + + trace_ssam_ei_rx_corrupt_syn(data->len); + + data->ptr[1] = 0xb3; /* Set second byte of SYN to "random" value. */ +} + +static void ssh_ptl_rx_inject_invalid_data(struct ssh_ptl *ptl, + struct ssam_span *frame) +{ + size_t payload_len, message_len; + struct ssh_frame *sshf; + + /* Ignore incomplete messages, will get handled once it's complete. */ + if (frame->len < SSH_MESSAGE_LENGTH(0)) + return; + + /* Ignore incomplete messages, part 2. */ + payload_len = get_unaligned_le16(&frame->ptr[SSH_MSGOFFSET_FRAME(len)]); + message_len = SSH_MESSAGE_LENGTH(payload_len); + if (frame->len < message_len) + return; + + if (likely(!ssh_ptl_should_corrupt_rx_data())) + return; + + sshf = (struct ssh_frame *)&frame->ptr[SSH_MSGOFFSET_FRAME(type)]; + trace_ssam_ei_rx_corrupt_data(sshf); + + /* + * Flip bits in first byte of payload checksum. This is basically + * equivalent to a payload/frame data error without us having to worry + * about (the, arguably pretty small, probability of) accidental + * checksum collisions. + */ + frame->ptr[frame->len - 2] = ~frame->ptr[frame->len - 2]; +} + +#else /* CONFIG_SURFACE_AGGREGATOR_ERROR_INJECTION */ + +static inline bool ssh_ptl_should_drop_packet(struct ssh_packet *packet) +{ + return false; +} + +static inline int ssh_ptl_write_buf(struct ssh_ptl *ptl, + struct ssh_packet *packet, + const unsigned char *buf, + size_t count) +{ + return serdev_device_write_buf(ptl->serdev, buf, count); +} + +static inline void ssh_ptl_tx_inject_invalid_data(struct ssh_packet *packet) +{ +} + +static inline void ssh_ptl_rx_inject_invalid_syn(struct ssh_ptl *ptl, + struct ssam_span *data) +{ +} + +static inline void ssh_ptl_rx_inject_invalid_data(struct ssh_ptl *ptl, + struct ssam_span *frame) +{ +} + +#endif /* CONFIG_SURFACE_AGGREGATOR_ERROR_INJECTION */ + static void __ssh_ptl_packet_release(struct kref *kref) { struct ssh_packet *p = container_of(kref, struct ssh_packet, refcnt); @@ -776,6 +1057,13 @@ static int ssh_ptl_tx_packet(struct ssh_ptl *ptl, struct ssh_packet *packet) if (unlikely(!packet->data.ptr)) return 0; + /* Error injection: drop packet to simulate transmission problem. */ + if (ssh_ptl_should_drop_packet(packet)) + return 0; + + /* Error injection: simulate invalid packet data. */ + ssh_ptl_tx_inject_invalid_data(packet); + ptl_dbg(ptl, "tx: sending data (length: %zu)\n", packet->data.len); print_hex_dump_debug("tx: ", DUMP_PREFIX_OFFSET, 16, 1, packet->data.ptr, packet->data.len, false); @@ -787,7 +1075,7 @@ static int ssh_ptl_tx_packet(struct ssh_ptl *ptl, struct ssh_packet *packet) buf = packet->data.ptr + offset; len = packet->data.len - offset; - status = serdev_device_write_buf(ptl->serdev, buf, len); + status = ssh_ptl_write_buf(ptl, packet, buf, len); if (status < 0) return status; @@ -1400,6 +1688,9 @@ static size_t ssh_ptl_rx_eval(struct ssh_ptl *ptl, struct ssam_span *source) bool syn_found; int status; + /* Error injection: Modify data to simulate corrupt SYN bytes. */ + ssh_ptl_rx_inject_invalid_syn(ptl, source); + /* Find SYN. */ syn_found = sshp_find_syn(source, &aligned); @@ -1430,6 +1721,9 @@ static size_t ssh_ptl_rx_eval(struct ssh_ptl *ptl, struct ssam_span *source) if (unlikely(!syn_found)) return aligned.ptr - source->ptr; + /* Error injection: Modify data to simulate corruption. */ + ssh_ptl_rx_inject_invalid_data(ptl, &aligned); + /* Parse and validate frame. */ status = sshp_parse_frame(&ptl->serdev->dev, &aligned, &frame, &payload, SSH_PTL_RX_BUF_LEN); diff --git a/drivers/platform/surface/aggregator/ssh_request_layer.c b/drivers/platform/surface/aggregator/ssh_request_layer.c index b649d71840fd..bb1c862411a2 100644 --- a/drivers/platform/surface/aggregator/ssh_request_layer.c +++ b/drivers/platform/surface/aggregator/ssh_request_layer.c @@ -8,6 +8,7 @@ #include #include #include +#include #include #include #include @@ -58,6 +59,30 @@ */ #define SSH_RTL_TX_BATCH 10 +#ifdef CONFIG_SURFACE_AGGREGATOR_ERROR_INJECTION + +/** + * ssh_rtl_should_drop_response() - Error injection hook to drop request + * responses. + * + * Useful to cause request transmission timeouts in the driver by dropping the + * response to a request. + */ +static noinline bool ssh_rtl_should_drop_response(void) +{ + return false; +} +ALLOW_ERROR_INJECTION(ssh_rtl_should_drop_response, TRUE); + +#else + +static inline bool ssh_rtl_should_drop_response(void) +{ + return false; +} + +#endif + static u16 ssh_request_get_rqid(struct ssh_request *rqst) { return get_unaligned_le16(rqst->packet.data.ptr @@ -459,6 +484,16 @@ static void ssh_rtl_complete(struct ssh_rtl *rtl, if (unlikely(ssh_request_get_rqid(p) != rqid)) continue; + /* Simulate response timeout. */ + if (ssh_rtl_should_drop_response()) { + spin_unlock(&rtl->pending.lock); + + trace_ssam_ei_rx_drop_response(p); + rtl_info(rtl, "request error injection: dropping response for request %p\n", + &p->packet); + return; + } + /* * Mark as "response received" and "locked" as we're going to * complete it. diff --git a/drivers/platform/surface/aggregator/trace.h b/drivers/platform/surface/aggregator/trace.h index dcca8007d876..eb332bb53ae4 100644 --- a/drivers/platform/surface/aggregator/trace.h +++ b/drivers/platform/surface/aggregator/trace.h @@ -565,6 +565,28 @@ DECLARE_EVENT_CLASS(ssam_pending_class, TP_ARGS(pending) \ ) +DECLARE_EVENT_CLASS(ssam_data_class, + TP_PROTO(size_t length), + + TP_ARGS(length), + + TP_STRUCT__entry( + __field(size_t, length) + ), + + TP_fast_assign( + __entry->length = length; + ), + + TP_printk("length=%zu", __entry->length) +); + +#define DEFINE_SSAM_DATA_EVENT(name) \ + DEFINE_EVENT(ssam_data_class, ssam_##name, \ + TP_PROTO(size_t length), \ + TP_ARGS(length) \ + ) + DEFINE_SSAM_FRAME_EVENT(rx_frame_received); DEFINE_SSAM_COMMAND_EVENT(rx_response_received); DEFINE_SSAM_COMMAND_EVENT(rx_event_received); @@ -583,6 +605,15 @@ DEFINE_SSAM_REQUEST_EVENT(request_cancel); DEFINE_SSAM_REQUEST_STATUS_EVENT(request_complete); DEFINE_SSAM_PENDING_EVENT(rtl_timeout_reap); +DEFINE_SSAM_PACKET_EVENT(ei_tx_drop_ack_packet); +DEFINE_SSAM_PACKET_EVENT(ei_tx_drop_nak_packet); +DEFINE_SSAM_PACKET_EVENT(ei_tx_drop_dsq_packet); +DEFINE_SSAM_PACKET_STATUS_EVENT(ei_tx_fail_write); +DEFINE_SSAM_PACKET_EVENT(ei_tx_corrupt_data); +DEFINE_SSAM_DATA_EVENT(ei_rx_corrupt_syn); +DEFINE_SSAM_FRAME_EVENT(ei_rx_corrupt_data); +DEFINE_SSAM_REQUEST_EVENT(ei_rx_drop_response); + DEFINE_SSAM_ALLOC_EVENT(ctrl_packet_alloc); DEFINE_SSAM_FREE_EVENT(ctrl_packet_free); -- cgit v1.2.3 From eb0e90a82098d4a48308abb87d2087578a83987f Mon Sep 17 00:00:00 2001 From: Maximilian Luz Date: Mon, 21 Dec 2020 19:39:56 +0100 Subject: platform/surface: aggregator: Add dedicated bus and device type The Surface Aggregator EC provides varying functionality, depending on the Surface device. To manage this functionality, we use dedicated client devices for each subsystem or virtual device of the EC. While some of these clients are described as standard devices in ACPI and the corresponding client drivers can be implemented as platform drivers in the kernel (making use of the controller API already present), many devices, especially on newer Surface models, cannot be found there. To simplify management of these devices, we introduce a new bus and client device type for the Surface Aggregator subsystem. The new device type takes care of managing the controller reference, essentially guaranteeing its validity for as long as the client device exists, thus alleviating the need to manually establish device links for that purpose in the client driver (as has to be done with the platform devices). Signed-off-by: Maximilian Luz Reviewed-by: Hans de Goede Link: https://lore.kernel.org/r/20201221183959.1186143-7-luzmaximilian@gmail.com Signed-off-by: Hans de Goede --- drivers/platform/surface/aggregator/Kconfig | 12 + drivers/platform/surface/aggregator/Makefile | 4 + drivers/platform/surface/aggregator/bus.c | 415 +++++++++++++++++++++++++++ drivers/platform/surface/aggregator/bus.h | 27 ++ drivers/platform/surface/aggregator/core.c | 12 + 5 files changed, 470 insertions(+) create mode 100644 drivers/platform/surface/aggregator/bus.c create mode 100644 drivers/platform/surface/aggregator/bus.h (limited to 'drivers/platform/surface') diff --git a/drivers/platform/surface/aggregator/Kconfig b/drivers/platform/surface/aggregator/Kconfig index e417bac67088..3aaeea9f0433 100644 --- a/drivers/platform/surface/aggregator/Kconfig +++ b/drivers/platform/surface/aggregator/Kconfig @@ -41,6 +41,18 @@ menuconfig SURFACE_AGGREGATOR module, y if you want to build it into the kernel and n if you don't want it at all. +config SURFACE_AGGREGATOR_BUS + bool "Surface System Aggregator Module Bus" + depends on SURFACE_AGGREGATOR + default y + help + Expands the Surface System Aggregator Module (SSAM) core driver by + providing a dedicated bus and client-device type. + + This bus and device type are intended to provide and simplify support + for non-platform and non-ACPI SSAM devices, i.e. SSAM devices that are + not auto-detectable via the conventional means (e.g. ACPI). + config SURFACE_AGGREGATOR_ERROR_INJECTION bool "Surface System Aggregator Module Error Injection Capabilities" depends on SURFACE_AGGREGATOR diff --git a/drivers/platform/surface/aggregator/Makefile b/drivers/platform/surface/aggregator/Makefile index b8b24c8ec310..c112e2c7112b 100644 --- a/drivers/platform/surface/aggregator/Makefile +++ b/drivers/platform/surface/aggregator/Makefile @@ -11,3 +11,7 @@ surface_aggregator-objs += ssh_parser.o surface_aggregator-objs += ssh_packet_layer.o surface_aggregator-objs += ssh_request_layer.o surface_aggregator-objs += controller.o + +ifeq ($(CONFIG_SURFACE_AGGREGATOR_BUS),y) +surface_aggregator-objs += bus.o +endif diff --git a/drivers/platform/surface/aggregator/bus.c b/drivers/platform/surface/aggregator/bus.c new file mode 100644 index 000000000000..a9b660af0917 --- /dev/null +++ b/drivers/platform/surface/aggregator/bus.c @@ -0,0 +1,415 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Surface System Aggregator Module bus and device integration. + * + * Copyright (C) 2019-2020 Maximilian Luz + */ + +#include +#include + +#include +#include + +#include "bus.h" +#include "controller.h" + +static ssize_t modalias_show(struct device *dev, struct device_attribute *attr, + char *buf) +{ + struct ssam_device *sdev = to_ssam_device(dev); + + return sysfs_emit(buf, "ssam:d%02Xc%02Xt%02Xi%02Xf%02X\n", + sdev->uid.domain, sdev->uid.category, sdev->uid.target, + sdev->uid.instance, sdev->uid.function); +} +static DEVICE_ATTR_RO(modalias); + +static struct attribute *ssam_device_attrs[] = { + &dev_attr_modalias.attr, + NULL, +}; +ATTRIBUTE_GROUPS(ssam_device); + +static int ssam_device_uevent(struct device *dev, struct kobj_uevent_env *env) +{ + struct ssam_device *sdev = to_ssam_device(dev); + + return add_uevent_var(env, "MODALIAS=ssam:d%02Xc%02Xt%02Xi%02Xf%02X", + sdev->uid.domain, sdev->uid.category, + sdev->uid.target, sdev->uid.instance, + sdev->uid.function); +} + +static void ssam_device_release(struct device *dev) +{ + struct ssam_device *sdev = to_ssam_device(dev); + + ssam_controller_put(sdev->ctrl); + kfree(sdev); +} + +const struct device_type ssam_device_type = { + .name = "surface_aggregator_device", + .groups = ssam_device_groups, + .uevent = ssam_device_uevent, + .release = ssam_device_release, +}; +EXPORT_SYMBOL_GPL(ssam_device_type); + +/** + * ssam_device_alloc() - Allocate and initialize a SSAM client device. + * @ctrl: The controller under which the device should be added. + * @uid: The UID of the device to be added. + * + * Allocates and initializes a new client device. The parent of the device + * will be set to the controller device and the name will be set based on the + * UID. Note that the device still has to be added via ssam_device_add(). + * Refer to that function for more details. + * + * Return: Returns the newly allocated and initialized SSAM client device, or + * %NULL if it could not be allocated. + */ +struct ssam_device *ssam_device_alloc(struct ssam_controller *ctrl, + struct ssam_device_uid uid) +{ + struct ssam_device *sdev; + + sdev = kzalloc(sizeof(*sdev), GFP_KERNEL); + if (!sdev) + return NULL; + + device_initialize(&sdev->dev); + sdev->dev.bus = &ssam_bus_type; + sdev->dev.type = &ssam_device_type; + sdev->dev.parent = ssam_controller_device(ctrl); + sdev->ctrl = ssam_controller_get(ctrl); + sdev->uid = uid; + + dev_set_name(&sdev->dev, "%02x:%02x:%02x:%02x:%02x", + sdev->uid.domain, sdev->uid.category, sdev->uid.target, + sdev->uid.instance, sdev->uid.function); + + return sdev; +} +EXPORT_SYMBOL_GPL(ssam_device_alloc); + +/** + * ssam_device_add() - Add a SSAM client device. + * @sdev: The SSAM client device to be added. + * + * Added client devices must be guaranteed to always have a valid and active + * controller. Thus, this function will fail with %-ENODEV if the controller + * of the device has not been initialized yet, has been suspended, or has been + * shut down. + * + * The caller of this function should ensure that the corresponding call to + * ssam_device_remove() is issued before the controller is shut down. If the + * added device is a direct child of the controller device (default), it will + * be automatically removed when the controller is shut down. + * + * By default, the controller device will become the parent of the newly + * created client device. The parent may be changed before ssam_device_add is + * called, but care must be taken that a) the correct suspend/resume ordering + * is guaranteed and b) the client device does not outlive the controller, + * i.e. that the device is removed before the controller is being shut down. + * In case these guarantees have to be manually enforced, please refer to the + * ssam_client_link() and ssam_client_bind() functions, which are intended to + * set up device-links for this purpose. + * + * Return: Returns zero on success, a negative error code on failure. + */ +int ssam_device_add(struct ssam_device *sdev) +{ + int status; + + /* + * Ensure that we can only add new devices to a controller if it has + * been started and is not going away soon. This works in combination + * with ssam_controller_remove_clients to ensure driver presence for the + * controller device, i.e. it ensures that the controller (sdev->ctrl) + * is always valid and can be used for requests as long as the client + * device we add here is registered as child under it. This essentially + * guarantees that the client driver can always expect the preconditions + * for functions like ssam_request_sync (controller has to be started + * and is not suspended) to hold and thus does not have to check for + * them. + * + * Note that for this to work, the controller has to be a parent device. + * If it is not a direct parent, care has to be taken that the device is + * removed via ssam_device_remove(), as device_unregister does not + * remove child devices recursively. + */ + ssam_controller_statelock(sdev->ctrl); + + if (sdev->ctrl->state != SSAM_CONTROLLER_STARTED) { + ssam_controller_stateunlock(sdev->ctrl); + return -ENODEV; + } + + status = device_add(&sdev->dev); + + ssam_controller_stateunlock(sdev->ctrl); + return status; +} +EXPORT_SYMBOL_GPL(ssam_device_add); + +/** + * ssam_device_remove() - Remove a SSAM client device. + * @sdev: The device to remove. + * + * Removes and unregisters the provided SSAM client device. + */ +void ssam_device_remove(struct ssam_device *sdev) +{ + device_unregister(&sdev->dev); +} +EXPORT_SYMBOL_GPL(ssam_device_remove); + +/** + * ssam_device_id_compatible() - Check if a device ID matches a UID. + * @id: The device ID as potential match. + * @uid: The device UID matching against. + * + * Check if the given ID is a match for the given UID, i.e. if a device with + * the provided UID is compatible to the given ID following the match rules + * described in its &ssam_device_id.match_flags member. + * + * Return: Returns %true if the given UID is compatible to the match rule + * described by the given ID, %false otherwise. + */ +static bool ssam_device_id_compatible(const struct ssam_device_id *id, + struct ssam_device_uid uid) +{ + if (id->domain != uid.domain || id->category != uid.category) + return false; + + if ((id->match_flags & SSAM_MATCH_TARGET) && id->target != uid.target) + return false; + + if ((id->match_flags & SSAM_MATCH_INSTANCE) && id->instance != uid.instance) + return false; + + if ((id->match_flags & SSAM_MATCH_FUNCTION) && id->function != uid.function) + return false; + + return true; +} + +/** + * ssam_device_id_is_null() - Check if a device ID is null. + * @id: The device ID to check. + * + * Check if a given device ID is null, i.e. all zeros. Used to check for the + * end of ``MODULE_DEVICE_TABLE(ssam, ...)`` or similar lists. + * + * Return: Returns %true if the given ID represents a null ID, %false + * otherwise. + */ +static bool ssam_device_id_is_null(const struct ssam_device_id *id) +{ + return id->match_flags == 0 && + id->domain == 0 && + id->category == 0 && + id->target == 0 && + id->instance == 0 && + id->function == 0 && + id->driver_data == 0; +} + +/** + * ssam_device_id_match() - Find the matching ID table entry for the given UID. + * @table: The table to search in. + * @uid: The UID to matched against the individual table entries. + * + * Find the first match for the provided device UID in the provided ID table + * and return it. Returns %NULL if no match could be found. + */ +const struct ssam_device_id *ssam_device_id_match(const struct ssam_device_id *table, + const struct ssam_device_uid uid) +{ + const struct ssam_device_id *id; + + for (id = table; !ssam_device_id_is_null(id); ++id) + if (ssam_device_id_compatible(id, uid)) + return id; + + return NULL; +} +EXPORT_SYMBOL_GPL(ssam_device_id_match); + +/** + * ssam_device_get_match() - Find and return the ID matching the device in the + * ID table of the bound driver. + * @dev: The device for which to get the matching ID table entry. + * + * Find the fist match for the UID of the device in the ID table of the + * currently bound driver and return it. Returns %NULL if the device does not + * have a driver bound to it, the driver does not have match_table (i.e. it is + * %NULL), or there is no match in the driver's match_table. + * + * This function essentially calls ssam_device_id_match() with the ID table of + * the bound device driver and the UID of the device. + * + * Return: Returns the first match for the UID of the device in the device + * driver's match table, or %NULL if no such match could be found. + */ +const struct ssam_device_id *ssam_device_get_match(const struct ssam_device *dev) +{ + const struct ssam_device_driver *sdrv; + + sdrv = to_ssam_device_driver(dev->dev.driver); + if (!sdrv) + return NULL; + + if (!sdrv->match_table) + return NULL; + + return ssam_device_id_match(sdrv->match_table, dev->uid); +} +EXPORT_SYMBOL_GPL(ssam_device_get_match); + +/** + * ssam_device_get_match_data() - Find the ID matching the device in the + * ID table of the bound driver and return its ``driver_data`` member. + * @dev: The device for which to get the match data. + * + * Find the fist match for the UID of the device in the ID table of the + * corresponding driver and return its driver_data. Returns %NULL if the + * device does not have a driver bound to it, the driver does not have + * match_table (i.e. it is %NULL), there is no match in the driver's + * match_table, or the match does not have any driver_data. + * + * This function essentially calls ssam_device_get_match() and, if any match + * could be found, returns its ``struct ssam_device_id.driver_data`` member. + * + * Return: Returns the driver data associated with the first match for the UID + * of the device in the device driver's match table, or %NULL if no such match + * could be found. + */ +const void *ssam_device_get_match_data(const struct ssam_device *dev) +{ + const struct ssam_device_id *id; + + id = ssam_device_get_match(dev); + if (!id) + return NULL; + + return (const void *)id->driver_data; +} +EXPORT_SYMBOL_GPL(ssam_device_get_match_data); + +static int ssam_bus_match(struct device *dev, struct device_driver *drv) +{ + struct ssam_device_driver *sdrv = to_ssam_device_driver(drv); + struct ssam_device *sdev = to_ssam_device(dev); + + if (!is_ssam_device(dev)) + return 0; + + return !!ssam_device_id_match(sdrv->match_table, sdev->uid); +} + +static int ssam_bus_probe(struct device *dev) +{ + return to_ssam_device_driver(dev->driver) + ->probe(to_ssam_device(dev)); +} + +static int ssam_bus_remove(struct device *dev) +{ + struct ssam_device_driver *sdrv = to_ssam_device_driver(dev->driver); + + if (sdrv->remove) + sdrv->remove(to_ssam_device(dev)); + + return 0; +} + +struct bus_type ssam_bus_type = { + .name = "surface_aggregator", + .match = ssam_bus_match, + .probe = ssam_bus_probe, + .remove = ssam_bus_remove, +}; +EXPORT_SYMBOL_GPL(ssam_bus_type); + +/** + * __ssam_device_driver_register() - Register a SSAM client device driver. + * @sdrv: The driver to register. + * @owner: The module owning the provided driver. + * + * Please refer to the ssam_device_driver_register() macro for the normal way + * to register a driver from inside its owning module. + */ +int __ssam_device_driver_register(struct ssam_device_driver *sdrv, + struct module *owner) +{ + sdrv->driver.owner = owner; + sdrv->driver.bus = &ssam_bus_type; + + /* force drivers to async probe so I/O is possible in probe */ + sdrv->driver.probe_type = PROBE_PREFER_ASYNCHRONOUS; + + return driver_register(&sdrv->driver); +} +EXPORT_SYMBOL_GPL(__ssam_device_driver_register); + +/** + * ssam_device_driver_unregister - Unregister a SSAM device driver. + * @sdrv: The driver to unregister. + */ +void ssam_device_driver_unregister(struct ssam_device_driver *sdrv) +{ + driver_unregister(&sdrv->driver); +} +EXPORT_SYMBOL_GPL(ssam_device_driver_unregister); + +static int ssam_remove_device(struct device *dev, void *_data) +{ + struct ssam_device *sdev = to_ssam_device(dev); + + if (is_ssam_device(dev)) + ssam_device_remove(sdev); + + return 0; +} + +/** + * ssam_controller_remove_clients() - Remove SSAM client devices registered as + * direct children under the given controller. + * @ctrl: The controller to remove all direct clients for. + * + * Remove all SSAM client devices registered as direct children under the + * given controller. Note that this only accounts for direct children of the + * controller device. This does not take care of any client devices where the + * parent device has been manually set before calling ssam_device_add. Refer + * to ssam_device_add()/ssam_device_remove() for more details on those cases. + * + * To avoid new devices being added in parallel to this call, the main + * controller lock (not statelock) must be held during this (and if + * necessary, any subsequent deinitialization) call. + */ +void ssam_controller_remove_clients(struct ssam_controller *ctrl) +{ + struct device *dev; + + dev = ssam_controller_device(ctrl); + device_for_each_child_reverse(dev, NULL, ssam_remove_device); +} + +/** + * ssam_bus_register() - Register and set-up the SSAM client device bus. + */ +int ssam_bus_register(void) +{ + return bus_register(&ssam_bus_type); +} + +/** + * ssam_bus_unregister() - Unregister the SSAM client device bus. + */ +void ssam_bus_unregister(void) +{ + return bus_unregister(&ssam_bus_type); +} diff --git a/drivers/platform/surface/aggregator/bus.h b/drivers/platform/surface/aggregator/bus.h new file mode 100644 index 000000000000..7712baaed6a5 --- /dev/null +++ b/drivers/platform/surface/aggregator/bus.h @@ -0,0 +1,27 @@ +/* SPDX-License-Identifier: GPL-2.0+ */ +/* + * Surface System Aggregator Module bus and device integration. + * + * Copyright (C) 2019-2020 Maximilian Luz + */ + +#ifndef _SURFACE_AGGREGATOR_BUS_H +#define _SURFACE_AGGREGATOR_BUS_H + +#include + +#ifdef CONFIG_SURFACE_AGGREGATOR_BUS + +void ssam_controller_remove_clients(struct ssam_controller *ctrl); + +int ssam_bus_register(void); +void ssam_bus_unregister(void); + +#else /* CONFIG_SURFACE_AGGREGATOR_BUS */ + +static inline void ssam_controller_remove_clients(struct ssam_controller *ctrl) {} +static inline int ssam_bus_register(void) { return 0; } +static inline void ssam_bus_unregister(void) {} + +#endif /* CONFIG_SURFACE_AGGREGATOR_BUS */ +#endif /* _SURFACE_AGGREGATOR_BUS_H */ diff --git a/drivers/platform/surface/aggregator/core.c b/drivers/platform/surface/aggregator/core.c index b6a9dea53592..8dc2c267bcd6 100644 --- a/drivers/platform/surface/aggregator/core.c +++ b/drivers/platform/surface/aggregator/core.c @@ -22,6 +22,8 @@ #include #include + +#include "bus.h" #include "controller.h" #define CREATE_TRACE_POINTS @@ -739,6 +741,9 @@ static void ssam_serial_hub_remove(struct serdev_device *serdev) sysfs_remove_group(&serdev->dev.kobj, &ssam_sam_group); ssam_controller_lock(ctrl); + /* Remove all client devices. */ + ssam_controller_remove_clients(ctrl); + /* Act as if suspending to silence events. */ status = ssam_ctrl_notif_display_off(ctrl); if (status) { @@ -791,6 +796,10 @@ static int __init ssam_core_init(void) { int status; + status = ssam_bus_register(); + if (status) + goto err_bus; + status = ssh_ctrl_packet_cache_init(); if (status) goto err_cpkg; @@ -810,6 +819,8 @@ err_register: err_evitem: ssh_ctrl_packet_cache_destroy(); err_cpkg: + ssam_bus_unregister(); +err_bus: return status; } module_init(ssam_core_init); @@ -819,6 +830,7 @@ static void __exit ssam_core_exit(void) serdev_device_driver_unregister(&ssam_serial_hub); ssam_event_item_cache_destroy(); ssh_ctrl_packet_cache_destroy(); + ssam_bus_unregister(); } module_exit(ssam_core_exit); -- cgit v1.2.3 From 178f6ab77e617c984d6520b92e747075a12676ff Mon Sep 17 00:00:00 2001 From: Maximilian Luz Date: Mon, 21 Dec 2020 19:39:58 +0100 Subject: platform/surface: Add Surface Aggregator user-space interface Add a misc-device providing user-space access to the Surface Aggregator EC, mainly intended for debugging, testing, and reverse-engineering. This interface gives user-space applications the ability to send requests to the EC and receive the corresponding responses. The device-file is managed by a pseudo platform-device and corresponding driver to avoid dependence on the dedicated bus, allowing it to be loaded in a minimal configuration. A python library and scripts to access this device can be found at [1]. [1]: https://github.com/linux-surface/surface-aggregator-module/tree/master/scripts/ssam Signed-off-by: Maximilian Luz Link: https://lore.kernel.org/r/20201221183959.1186143-9-luzmaximilian@gmail.com Signed-off-by: Hans de Goede --- drivers/platform/surface/Kconfig | 17 ++ drivers/platform/surface/Makefile | 1 + drivers/platform/surface/surface_aggregator_cdev.c | 303 +++++++++++++++++++++ 3 files changed, 321 insertions(+) create mode 100644 drivers/platform/surface/surface_aggregator_cdev.c (limited to 'drivers/platform/surface') diff --git a/drivers/platform/surface/Kconfig b/drivers/platform/surface/Kconfig index 2916a47b130e..988b2de6b500 100644 --- a/drivers/platform/surface/Kconfig +++ b/drivers/platform/surface/Kconfig @@ -41,6 +41,23 @@ config SURFACE_3_POWER_OPREGION This driver provides support for ACPI operation region of the Surface 3 battery platform driver. +config SURFACE_AGGREGATOR_CDEV + tristate "Surface System Aggregator Module User-Space Interface" + depends on SURFACE_AGGREGATOR + help + Provides a misc-device interface to the Surface System Aggregator + Module (SSAM) controller. + + This option provides a module (called surface_aggregator_cdev), that, + when loaded, will add a client device (and its respective driver) to + the SSAM controller. Said client device manages a misc-device + interface (/dev/surface/aggregator), which can be used by user-space + tools to directly communicate with the SSAM EC by sending requests and + receiving the corresponding responses. + + The provided interface is intended for debugging and development only, + and should not be used otherwise. + config SURFACE_GPE tristate "Surface GPE/Lid Support Driver" depends on DMI diff --git a/drivers/platform/surface/Makefile b/drivers/platform/surface/Makefile index 034134fe0264..161f0ad05795 100644 --- a/drivers/platform/surface/Makefile +++ b/drivers/platform/surface/Makefile @@ -8,5 +8,6 @@ obj-$(CONFIG_SURFACE3_WMI) += surface3-wmi.o obj-$(CONFIG_SURFACE_3_BUTTON) += surface3_button.o obj-$(CONFIG_SURFACE_3_POWER_OPREGION) += surface3_power.o obj-$(CONFIG_SURFACE_AGGREGATOR) += aggregator/ +obj-$(CONFIG_SURFACE_AGGREGATOR_CDEV) += surface_aggregator_cdev.o obj-$(CONFIG_SURFACE_GPE) += surface_gpe.o obj-$(CONFIG_SURFACE_PRO3_BUTTON) += surfacepro3_button.o diff --git a/drivers/platform/surface/surface_aggregator_cdev.c b/drivers/platform/surface/surface_aggregator_cdev.c new file mode 100644 index 000000000000..340d15b148b9 --- /dev/null +++ b/drivers/platform/surface/surface_aggregator_cdev.c @@ -0,0 +1,303 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Provides user-space access to the SSAM EC via the /dev/surface/aggregator + * misc device. Intended for debugging and development. + * + * Copyright (C) 2020 Maximilian Luz + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include + +#define SSAM_CDEV_DEVICE_NAME "surface_aggregator_cdev" + +struct ssam_cdev { + struct kref kref; + struct rw_semaphore lock; + struct ssam_controller *ctrl; + struct miscdevice mdev; +}; + +static void __ssam_cdev_release(struct kref *kref) +{ + kfree(container_of(kref, struct ssam_cdev, kref)); +} + +static struct ssam_cdev *ssam_cdev_get(struct ssam_cdev *cdev) +{ + if (cdev) + kref_get(&cdev->kref); + + return cdev; +} + +static void ssam_cdev_put(struct ssam_cdev *cdev) +{ + if (cdev) + kref_put(&cdev->kref, __ssam_cdev_release); +} + +static int ssam_cdev_device_open(struct inode *inode, struct file *filp) +{ + struct miscdevice *mdev = filp->private_data; + struct ssam_cdev *cdev = container_of(mdev, struct ssam_cdev, mdev); + + filp->private_data = ssam_cdev_get(cdev); + return stream_open(inode, filp); +} + +static int ssam_cdev_device_release(struct inode *inode, struct file *filp) +{ + ssam_cdev_put(filp->private_data); + return 0; +} + +static long ssam_cdev_request(struct ssam_cdev *cdev, unsigned long arg) +{ + struct ssam_cdev_request __user *r; + struct ssam_cdev_request rqst; + struct ssam_request spec; + struct ssam_response rsp; + const void __user *plddata; + void __user *rspdata; + int status = 0, ret = 0, tmp; + + r = (struct ssam_cdev_request __user *)arg; + ret = copy_struct_from_user(&rqst, sizeof(rqst), r, sizeof(*r)); + if (ret) + goto out; + + plddata = u64_to_user_ptr(rqst.payload.data); + rspdata = u64_to_user_ptr(rqst.response.data); + + /* Setup basic request fields. */ + spec.target_category = rqst.target_category; + spec.target_id = rqst.target_id; + spec.command_id = rqst.command_id; + spec.instance_id = rqst.instance_id; + spec.flags = 0; + spec.length = rqst.payload.length; + spec.payload = NULL; + + if (rqst.flags & SSAM_CDEV_REQUEST_HAS_RESPONSE) + spec.flags |= SSAM_REQUEST_HAS_RESPONSE; + + if (rqst.flags & SSAM_CDEV_REQUEST_UNSEQUENCED) + spec.flags |= SSAM_REQUEST_UNSEQUENCED; + + rsp.capacity = rqst.response.length; + rsp.length = 0; + rsp.pointer = NULL; + + /* Get request payload from user-space. */ + if (spec.length) { + if (!plddata) { + ret = -EINVAL; + goto out; + } + + spec.payload = kzalloc(spec.length, GFP_KERNEL); + if (!spec.payload) { + ret = -ENOMEM; + goto out; + } + + if (copy_from_user((void *)spec.payload, plddata, spec.length)) { + ret = -EFAULT; + goto out; + } + } + + /* Allocate response buffer. */ + if (rsp.capacity) { + if (!rspdata) { + ret = -EINVAL; + goto out; + } + + rsp.pointer = kzalloc(rsp.capacity, GFP_KERNEL); + if (!rsp.pointer) { + ret = -ENOMEM; + goto out; + } + } + + /* Perform request. */ + status = ssam_request_sync(cdev->ctrl, &spec, &rsp); + if (status) + goto out; + + /* Copy response to user-space. */ + if (rsp.length && copy_to_user(rspdata, rsp.pointer, rsp.length)) + ret = -EFAULT; + +out: + /* Always try to set response-length and status. */ + tmp = put_user(rsp.length, &r->response.length); + if (tmp) + ret = tmp; + + tmp = put_user(status, &r->status); + if (tmp) + ret = tmp; + + /* Cleanup. */ + kfree(spec.payload); + kfree(rsp.pointer); + + return ret; +} + +static long __ssam_cdev_device_ioctl(struct ssam_cdev *cdev, unsigned int cmd, + unsigned long arg) +{ + switch (cmd) { + case SSAM_CDEV_REQUEST: + return ssam_cdev_request(cdev, arg); + + default: + return -ENOTTY; + } +} + +static long ssam_cdev_device_ioctl(struct file *file, unsigned int cmd, + unsigned long arg) +{ + struct ssam_cdev *cdev = file->private_data; + long status; + + /* Ensure that controller is valid for as long as we need it. */ + if (down_read_killable(&cdev->lock)) + return -ERESTARTSYS; + + if (!cdev->ctrl) { + up_read(&cdev->lock); + return -ENODEV; + } + + status = __ssam_cdev_device_ioctl(cdev, cmd, arg); + + up_read(&cdev->lock); + return status; +} + +static const struct file_operations ssam_controller_fops = { + .owner = THIS_MODULE, + .open = ssam_cdev_device_open, + .release = ssam_cdev_device_release, + .unlocked_ioctl = ssam_cdev_device_ioctl, + .compat_ioctl = ssam_cdev_device_ioctl, + .llseek = noop_llseek, +}; + +static int ssam_dbg_device_probe(struct platform_device *pdev) +{ + struct ssam_controller *ctrl; + struct ssam_cdev *cdev; + int status; + + ctrl = ssam_client_bind(&pdev->dev); + if (IS_ERR(ctrl)) + return PTR_ERR(ctrl) == -ENODEV ? -EPROBE_DEFER : PTR_ERR(ctrl); + + cdev = kzalloc(sizeof(*cdev), GFP_KERNEL); + if (!cdev) + return -ENOMEM; + + kref_init(&cdev->kref); + init_rwsem(&cdev->lock); + cdev->ctrl = ctrl; + + cdev->mdev.parent = &pdev->dev; + cdev->mdev.minor = MISC_DYNAMIC_MINOR; + cdev->mdev.name = "surface_aggregator"; + cdev->mdev.nodename = "surface/aggregator"; + cdev->mdev.fops = &ssam_controller_fops; + + status = misc_register(&cdev->mdev); + if (status) { + kfree(cdev); + return status; + } + + platform_set_drvdata(pdev, cdev); + return 0; +} + +static int ssam_dbg_device_remove(struct platform_device *pdev) +{ + struct ssam_cdev *cdev = platform_get_drvdata(pdev); + + misc_deregister(&cdev->mdev); + + /* + * The controller is only guaranteed to be valid for as long as the + * driver is bound. Remove controller so that any lingering open files + * cannot access it any more after we're gone. + */ + down_write(&cdev->lock); + cdev->ctrl = NULL; + up_write(&cdev->lock); + + ssam_cdev_put(cdev); + return 0; +} + +static struct platform_device *ssam_cdev_device; + +static struct platform_driver ssam_cdev_driver = { + .probe = ssam_dbg_device_probe, + .remove = ssam_dbg_device_remove, + .driver = { + .name = SSAM_CDEV_DEVICE_NAME, + .probe_type = PROBE_PREFER_ASYNCHRONOUS, + }, +}; + +static int __init ssam_debug_init(void) +{ + int status; + + ssam_cdev_device = platform_device_alloc(SSAM_CDEV_DEVICE_NAME, + PLATFORM_DEVID_NONE); + if (!ssam_cdev_device) + return -ENOMEM; + + status = platform_device_add(ssam_cdev_device); + if (status) + goto err_device; + + status = platform_driver_register(&ssam_cdev_driver); + if (status) + goto err_driver; + + return 0; + +err_driver: + platform_device_del(ssam_cdev_device); +err_device: + platform_device_put(ssam_cdev_device); + return status; +} +module_init(ssam_debug_init); + +static void __exit ssam_debug_exit(void) +{ + platform_driver_unregister(&ssam_cdev_driver); + platform_device_unregister(ssam_cdev_device); +} +module_exit(ssam_debug_exit); + +MODULE_AUTHOR("Maximilian Luz "); +MODULE_DESCRIPTION("User-space interface for Surface System Aggregator Module"); +MODULE_LICENSE("GPL"); -- cgit v1.2.3 From fc00bc8ac1dada4085f9308f85f2d6359da0faa8 Mon Sep 17 00:00:00 2001 From: Maximilian Luz Date: Mon, 21 Dec 2020 19:39:59 +0100 Subject: platform/surface: Add Surface ACPI Notify driver The Surface ACPI Notify (SAN) device provides an ACPI interface to the Surface Aggregator EC, specifically the Surface Serial Hub interface. This interface allows EC requests to be made from ACPI code and can convert a subset of EC events back to ACPI notifications. Specifically, this interface provides a GenericSerialBus operation region ACPI code can execute a request by writing the request command data and payload to this operation region and reading back the corresponding response via a write-then-read operation. Furthermore, this interface provides a _DSM method to be called when certain events from the EC have been received, essentially turning them into ACPI notifications. The driver provided in this commit essentially takes care of translating the request data written to the operation region, executing the request, waiting for it to finish, and finally writing and translating back the response (if the request has one). Furthermore, this driver takes care of enabling the events handled via ACPI _DSM calls. Lastly, this driver also exposes an interface providing discrete GPU (dGPU) power-on notifications on the Surface Book 2, which are also received via the operation region interface (but not handled by the SAN driver directly), making them accessible to other drivers (such as a dGPU hot-plug driver that may be added later on). On 5th and 6th generation Surface devices (Surface Pro 5/2017, Pro 6, Book 2, Laptop 1 and 2), the SAN interface provides full battery and thermal subsystem access, as well as other EC based functionality. On those models, battery and thermal sensor devices are implemented as standard ACPI devices of that type, however, forward ACPI calls to the corresponding Surface Aggregator EC request via the SAN interface and receive corresponding notifications (e.g. battery information change) from it. This interface is therefore required to provide said functionality on those devices. Signed-off-by: Maximilian Luz Reviewed-by: Hans de Goede Link: https://lore.kernel.org/r/20201221183959.1186143-10-luzmaximilian@gmail.com Signed-off-by: Hans de Goede --- drivers/platform/surface/Kconfig | 19 + drivers/platform/surface/Makefile | 1 + drivers/platform/surface/surface_acpi_notify.c | 886 +++++++++++++++++++++++++ 3 files changed, 906 insertions(+) create mode 100644 drivers/platform/surface/surface_acpi_notify.c (limited to 'drivers/platform/surface') diff --git a/drivers/platform/surface/Kconfig b/drivers/platform/surface/Kconfig index 988b2de6b500..83b0a4c7b352 100644 --- a/drivers/platform/surface/Kconfig +++ b/drivers/platform/surface/Kconfig @@ -41,6 +41,25 @@ config SURFACE_3_POWER_OPREGION This driver provides support for ACPI operation region of the Surface 3 battery platform driver. +config SURFACE_ACPI_NOTIFY + tristate "Surface ACPI Notify Driver" + depends on SURFACE_AGGREGATOR + help + Surface ACPI Notify (SAN) driver for Microsoft Surface devices. + + This driver provides support for the ACPI interface (called SAN) of + the Surface System Aggregator Module (SSAM) EC. This interface is used + on 5th- and 6th-generation Microsoft Surface devices (including + Surface Pro 5 and 6, Surface Book 2, Surface Laptops 1 and 2, and in + reduced functionality on the Surface Laptop 3) to execute SSAM + requests directly from ACPI code, as well as receive SSAM events and + turn them into ACPI notifications. It essentially acts as a + translation layer between the SSAM controller and ACPI. + + Specifically, this driver may be needed for battery status reporting, + thermal sensor access, and real-time clock information, depending on + the Surface device in question. + config SURFACE_AGGREGATOR_CDEV tristate "Surface System Aggregator Module User-Space Interface" depends on SURFACE_AGGREGATOR diff --git a/drivers/platform/surface/Makefile b/drivers/platform/surface/Makefile index 161f0ad05795..3eb971006877 100644 --- a/drivers/platform/surface/Makefile +++ b/drivers/platform/surface/Makefile @@ -7,6 +7,7 @@ obj-$(CONFIG_SURFACE3_WMI) += surface3-wmi.o obj-$(CONFIG_SURFACE_3_BUTTON) += surface3_button.o obj-$(CONFIG_SURFACE_3_POWER_OPREGION) += surface3_power.o +obj-$(CONFIG_SURFACE_ACPI_NOTIFY) += surface_acpi_notify.o obj-$(CONFIG_SURFACE_AGGREGATOR) += aggregator/ obj-$(CONFIG_SURFACE_AGGREGATOR_CDEV) += surface_aggregator_cdev.o obj-$(CONFIG_SURFACE_GPE) += surface_gpe.o diff --git a/drivers/platform/surface/surface_acpi_notify.c b/drivers/platform/surface/surface_acpi_notify.c new file mode 100644 index 000000000000..8cd67a669c86 --- /dev/null +++ b/drivers/platform/surface/surface_acpi_notify.c @@ -0,0 +1,886 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Driver for the Surface ACPI Notify (SAN) interface/shim. + * + * Translates communication from ACPI to Surface System Aggregator Module + * (SSAM/SAM) requests and back, specifically SAM-over-SSH. Translates SSAM + * events back to ACPI notifications. Allows handling of discrete GPU + * notifications sent from ACPI via the SAN interface by providing them to any + * registered external driver. + * + * Copyright (C) 2019-2020 Maximilian Luz + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include + +struct san_data { + struct device *dev; + struct ssam_controller *ctrl; + + struct acpi_connection_info info; + + struct ssam_event_notifier nf_bat; + struct ssam_event_notifier nf_tmp; +}; + +#define to_san_data(ptr, member) \ + container_of(ptr, struct san_data, member) + + +/* -- dGPU notifier interface. ---------------------------------------------- */ + +struct san_rqsg_if { + struct rw_semaphore lock; + struct device *dev; + struct blocking_notifier_head nh; +}; + +static struct san_rqsg_if san_rqsg_if = { + .lock = __RWSEM_INITIALIZER(san_rqsg_if.lock), + .dev = NULL, + .nh = BLOCKING_NOTIFIER_INIT(san_rqsg_if.nh), +}; + +static int san_set_rqsg_interface_device(struct device *dev) +{ + int status = 0; + + down_write(&san_rqsg_if.lock); + if (!san_rqsg_if.dev && dev) + san_rqsg_if.dev = dev; + else + status = -EBUSY; + up_write(&san_rqsg_if.lock); + + return status; +} + +/** + * san_client_link() - Link client as consumer to SAN device. + * @client: The client to link. + * + * Sets up a device link between the provided client device as consumer and + * the SAN device as provider. This function can be used to ensure that the + * SAN interface has been set up and will be set up for as long as the driver + * of the client device is bound. This guarantees that, during that time, all + * dGPU events will be received by any registered notifier. + * + * The link will be automatically removed once the client device's driver is + * unbound. + * + * Return: Returns zero on success, %-ENXIO if the SAN interface has not been + * set up yet, and %-ENOMEM if device link creation failed. + */ +int san_client_link(struct device *client) +{ + const u32 flags = DL_FLAG_PM_RUNTIME | DL_FLAG_AUTOREMOVE_CONSUMER; + struct device_link *link; + + down_read(&san_rqsg_if.lock); + + if (!san_rqsg_if.dev) { + up_read(&san_rqsg_if.lock); + return -ENXIO; + } + + link = device_link_add(client, san_rqsg_if.dev, flags); + if (!link) { + up_read(&san_rqsg_if.lock); + return -ENOMEM; + } + + if (READ_ONCE(link->status) == DL_STATE_SUPPLIER_UNBIND) { + up_read(&san_rqsg_if.lock); + return -ENXIO; + } + + up_read(&san_rqsg_if.lock); + return 0; +} +EXPORT_SYMBOL_GPL(san_client_link); + +/** + * san_dgpu_notifier_register() - Register a SAN dGPU notifier. + * @nb: The notifier-block to register. + * + * Registers a SAN dGPU notifier, receiving any new SAN dGPU events sent from + * ACPI. The registered notifier will be called with &struct san_dgpu_event + * as notifier data and the command ID of that event as notifier action. + */ +int san_dgpu_notifier_register(struct notifier_block *nb) +{ + return blocking_notifier_chain_register(&san_rqsg_if.nh, nb); +} +EXPORT_SYMBOL_GPL(san_dgpu_notifier_register); + +/** + * san_dgpu_notifier_unregister() - Unregister a SAN dGPU notifier. + * @nb: The notifier-block to unregister. + */ +int san_dgpu_notifier_unregister(struct notifier_block *nb) +{ + return blocking_notifier_chain_unregister(&san_rqsg_if.nh, nb); +} +EXPORT_SYMBOL_GPL(san_dgpu_notifier_unregister); + +static int san_dgpu_notifier_call(struct san_dgpu_event *evt) +{ + int ret; + + ret = blocking_notifier_call_chain(&san_rqsg_if.nh, evt->command, evt); + return notifier_to_errno(ret); +} + + +/* -- ACPI _DSM event relay. ------------------------------------------------ */ + +#define SAN_DSM_REVISION 0 + +/* 93b666c5-70c6-469f-a215-3d487c91ab3c */ +static const guid_t SAN_DSM_UUID = + GUID_INIT(0x93b666c5, 0x70c6, 0x469f, 0xa2, 0x15, 0x3d, + 0x48, 0x7c, 0x91, 0xab, 0x3c); + +enum san_dsm_event_fn { + SAN_DSM_EVENT_FN_BAT1_STAT = 0x03, + SAN_DSM_EVENT_FN_BAT1_INFO = 0x04, + SAN_DSM_EVENT_FN_ADP1_STAT = 0x05, + SAN_DSM_EVENT_FN_ADP1_INFO = 0x06, + SAN_DSM_EVENT_FN_BAT2_STAT = 0x07, + SAN_DSM_EVENT_FN_BAT2_INFO = 0x08, + SAN_DSM_EVENT_FN_THERMAL = 0x09, + SAN_DSM_EVENT_FN_DPTF = 0x0a, +}; + +enum sam_event_cid_bat { + SAM_EVENT_CID_BAT_BIX = 0x15, + SAM_EVENT_CID_BAT_BST = 0x16, + SAM_EVENT_CID_BAT_ADP = 0x17, + SAM_EVENT_CID_BAT_PROT = 0x18, + SAM_EVENT_CID_BAT_DPTF = 0x4f, +}; + +enum sam_event_cid_tmp { + SAM_EVENT_CID_TMP_TRIP = 0x0b, +}; + +struct san_event_work { + struct delayed_work work; + struct device *dev; + struct ssam_event event; /* must be last */ +}; + +static int san_acpi_notify_event(struct device *dev, u64 func, + union acpi_object *param) +{ + acpi_handle san = ACPI_HANDLE(dev); + union acpi_object *obj; + int status = 0; + + if (!acpi_check_dsm(san, &SAN_DSM_UUID, SAN_DSM_REVISION, 1 << func)) + return 0; + + dev_dbg(dev, "notify event %#04llx\n", func); + + obj = acpi_evaluate_dsm_typed(san, &SAN_DSM_UUID, SAN_DSM_REVISION, + func, param, ACPI_TYPE_BUFFER); + if (!obj) + return -EFAULT; + + if (obj->buffer.length != 1 || obj->buffer.pointer[0] != 0) { + dev_err(dev, "got unexpected result from _DSM\n"); + status = -EPROTO; + } + + ACPI_FREE(obj); + return status; +} + +static int san_evt_bat_adp(struct device *dev, const struct ssam_event *event) +{ + int status; + + status = san_acpi_notify_event(dev, SAN_DSM_EVENT_FN_ADP1_STAT, NULL); + if (status) + return status; + + /* + * Ensure that the battery states get updated correctly. When the + * battery is fully charged and an adapter is plugged in, it sometimes + * is not updated correctly, instead showing it as charging. + * Explicitly trigger battery updates to fix this. + */ + + status = san_acpi_notify_event(dev, SAN_DSM_EVENT_FN_BAT1_STAT, NULL); + if (status) + return status; + + return san_acpi_notify_event(dev, SAN_DSM_EVENT_FN_BAT2_STAT, NULL); +} + +static int san_evt_bat_bix(struct device *dev, const struct ssam_event *event) +{ + enum san_dsm_event_fn fn; + + if (event->instance_id == 0x02) + fn = SAN_DSM_EVENT_FN_BAT2_INFO; + else + fn = SAN_DSM_EVENT_FN_BAT1_INFO; + + return san_acpi_notify_event(dev, fn, NULL); +} + +static int san_evt_bat_bst(struct device *dev, const struct ssam_event *event) +{ + enum san_dsm_event_fn fn; + + if (event->instance_id == 0x02) + fn = SAN_DSM_EVENT_FN_BAT2_STAT; + else + fn = SAN_DSM_EVENT_FN_BAT1_STAT; + + return san_acpi_notify_event(dev, fn, NULL); +} + +static int san_evt_bat_dptf(struct device *dev, const struct ssam_event *event) +{ + union acpi_object payload; + + /* + * The Surface ACPI expects a buffer and not a package. It specifically + * checks for ObjectType (Arg3) == 0x03. This will cause a warning in + * acpica/nsarguments.c, but that warning can be safely ignored. + */ + payload.type = ACPI_TYPE_BUFFER; + payload.buffer.length = event->length; + payload.buffer.pointer = (u8 *)&event->data[0]; + + return san_acpi_notify_event(dev, SAN_DSM_EVENT_FN_DPTF, &payload); +} + +static unsigned long san_evt_bat_delay(u8 cid) +{ + switch (cid) { + case SAM_EVENT_CID_BAT_ADP: + /* + * Wait for battery state to update before signaling adapter + * change. + */ + return msecs_to_jiffies(5000); + + case SAM_EVENT_CID_BAT_BST: + /* Ensure we do not miss anything important due to caching. */ + return msecs_to_jiffies(2000); + + default: + return 0; + } +} + +static bool san_evt_bat(const struct ssam_event *event, struct device *dev) +{ + int status; + + switch (event->command_id) { + case SAM_EVENT_CID_BAT_BIX: + status = san_evt_bat_bix(dev, event); + break; + + case SAM_EVENT_CID_BAT_BST: + status = san_evt_bat_bst(dev, event); + break; + + case SAM_EVENT_CID_BAT_ADP: + status = san_evt_bat_adp(dev, event); + break; + + case SAM_EVENT_CID_BAT_PROT: + /* + * TODO: Implement support for battery protection status change + * event. + */ + return true; + + case SAM_EVENT_CID_BAT_DPTF: + status = san_evt_bat_dptf(dev, event); + break; + + default: + return false; + } + + if (status) { + dev_err(dev, "error handling power event (cid = %#04x)\n", + event->command_id); + } + + return true; +} + +static void san_evt_bat_workfn(struct work_struct *work) +{ + struct san_event_work *ev; + + ev = container_of(work, struct san_event_work, work.work); + san_evt_bat(&ev->event, ev->dev); + kfree(ev); +} + +static u32 san_evt_bat_nf(struct ssam_event_notifier *nf, + const struct ssam_event *event) +{ + struct san_data *d = to_san_data(nf, nf_bat); + struct san_event_work *work; + unsigned long delay = san_evt_bat_delay(event->command_id); + + if (delay == 0) + return san_evt_bat(event, d->dev) ? SSAM_NOTIF_HANDLED : 0; + + work = kzalloc(sizeof(*work) + event->length, GFP_KERNEL); + if (!work) + return ssam_notifier_from_errno(-ENOMEM); + + INIT_DELAYED_WORK(&work->work, san_evt_bat_workfn); + work->dev = d->dev; + + memcpy(&work->event, event, sizeof(struct ssam_event) + event->length); + + schedule_delayed_work(&work->work, delay); + return SSAM_NOTIF_HANDLED; +} + +static int san_evt_tmp_trip(struct device *dev, const struct ssam_event *event) +{ + union acpi_object param; + + /* + * The Surface ACPI expects an integer and not a package. This will + * cause a warning in acpica/nsarguments.c, but that warning can be + * safely ignored. + */ + param.type = ACPI_TYPE_INTEGER; + param.integer.value = event->instance_id; + + return san_acpi_notify_event(dev, SAN_DSM_EVENT_FN_THERMAL, ¶m); +} + +static bool san_evt_tmp(const struct ssam_event *event, struct device *dev) +{ + int status; + + switch (event->command_id) { + case SAM_EVENT_CID_TMP_TRIP: + status = san_evt_tmp_trip(dev, event); + break; + + default: + return false; + } + + if (status) { + dev_err(dev, "error handling thermal event (cid = %#04x)\n", + event->command_id); + } + + return true; +} + +static u32 san_evt_tmp_nf(struct ssam_event_notifier *nf, + const struct ssam_event *event) +{ + struct san_data *d = to_san_data(nf, nf_tmp); + + return san_evt_tmp(event, d->dev) ? SSAM_NOTIF_HANDLED : 0; +} + + +/* -- ACPI GSB OperationRegion handler -------------------------------------- */ + +struct gsb_data_in { + u8 cv; +} __packed; + +struct gsb_data_rqsx { + u8 cv; /* Command value (san_gsb_request_cv). */ + u8 tc; /* Target category. */ + u8 tid; /* Target ID. */ + u8 iid; /* Instance ID. */ + u8 snc; /* Expect-response-flag. */ + u8 cid; /* Command ID. */ + u16 cdl; /* Payload length. */ + u8 pld[]; /* Payload. */ +} __packed; + +struct gsb_data_etwl { + u8 cv; /* Command value (should be 0x02). */ + u8 etw3; /* Unknown. */ + u8 etw4; /* Unknown. */ + u8 msg[]; /* Error message (ASCIIZ). */ +} __packed; + +struct gsb_data_out { + u8 status; /* _SSH communication status. */ + u8 len; /* _SSH payload length. */ + u8 pld[]; /* _SSH payload. */ +} __packed; + +union gsb_buffer_data { + struct gsb_data_in in; /* Common input. */ + struct gsb_data_rqsx rqsx; /* RQSX input. */ + struct gsb_data_etwl etwl; /* ETWL input. */ + struct gsb_data_out out; /* Output. */ +}; + +struct gsb_buffer { + u8 status; /* GSB AttribRawProcess status. */ + u8 len; /* GSB AttribRawProcess length. */ + union gsb_buffer_data data; +} __packed; + +#define SAN_GSB_MAX_RQSX_PAYLOAD (U8_MAX - 2 - sizeof(struct gsb_data_rqsx)) +#define SAN_GSB_MAX_RESPONSE (U8_MAX - 2 - sizeof(struct gsb_data_out)) + +#define SAN_GSB_COMMAND 0 + +enum san_gsb_request_cv { + SAN_GSB_REQUEST_CV_RQST = 0x01, + SAN_GSB_REQUEST_CV_ETWL = 0x02, + SAN_GSB_REQUEST_CV_RQSG = 0x03, +}; + +#define SAN_REQUEST_NUM_TRIES 5 + +static acpi_status san_etwl(struct san_data *d, struct gsb_buffer *b) +{ + struct gsb_data_etwl *etwl = &b->data.etwl; + + if (b->len < sizeof(struct gsb_data_etwl)) { + dev_err(d->dev, "invalid ETWL package (len = %d)\n", b->len); + return AE_OK; + } + + dev_err(d->dev, "ETWL(%#04x, %#04x): %.*s\n", etwl->etw3, etwl->etw4, + (unsigned int)(b->len - sizeof(struct gsb_data_etwl)), + (char *)etwl->msg); + + /* Indicate success. */ + b->status = 0x00; + b->len = 0x00; + + return AE_OK; +} + +static +struct gsb_data_rqsx *san_validate_rqsx(struct device *dev, const char *type, + struct gsb_buffer *b) +{ + struct gsb_data_rqsx *rqsx = &b->data.rqsx; + + if (b->len < sizeof(struct gsb_data_rqsx)) { + dev_err(dev, "invalid %s package (len = %d)\n", type, b->len); + return NULL; + } + + if (get_unaligned(&rqsx->cdl) != b->len - sizeof(struct gsb_data_rqsx)) { + dev_err(dev, "bogus %s package (len = %d, cdl = %d)\n", + type, b->len, get_unaligned(&rqsx->cdl)); + return NULL; + } + + if (get_unaligned(&rqsx->cdl) > SAN_GSB_MAX_RQSX_PAYLOAD) { + dev_err(dev, "payload for %s package too large (cdl = %d)\n", + type, get_unaligned(&rqsx->cdl)); + return NULL; + } + + return rqsx; +} + +static void gsb_rqsx_response_error(struct gsb_buffer *gsb, int status) +{ + gsb->status = 0x00; + gsb->len = 0x02; + gsb->data.out.status = (u8)(-status); + gsb->data.out.len = 0x00; +} + +static void gsb_rqsx_response_success(struct gsb_buffer *gsb, u8 *ptr, size_t len) +{ + gsb->status = 0x00; + gsb->len = len + 2; + gsb->data.out.status = 0x00; + gsb->data.out.len = len; + + if (len) + memcpy(&gsb->data.out.pld[0], ptr, len); +} + +static acpi_status san_rqst_fixup_suspended(struct san_data *d, + struct ssam_request *rqst, + struct gsb_buffer *gsb) +{ + if (rqst->target_category == SSAM_SSH_TC_BAS && rqst->command_id == 0x0D) { + u8 base_state = 1; + + /* Base state quirk: + * The base state may be queried from ACPI when the EC is still + * suspended. In this case it will return '-EPERM'. This query + * will only be triggered from the ACPI lid GPE interrupt, thus + * we are either in laptop or studio mode (base status 0x01 or + * 0x02). Furthermore, we will only get here if the device (and + * EC) have been suspended. + * + * We now assume that the device is in laptop mode (0x01). This + * has the drawback that it will wake the device when unfolding + * it in studio mode, but it also allows us to avoid actively + * waiting for the EC to wake up, which may incur a notable + * delay. + */ + + dev_dbg(d->dev, "rqst: fixup: base-state quirk\n"); + + gsb_rqsx_response_success(gsb, &base_state, sizeof(base_state)); + return AE_OK; + } + + gsb_rqsx_response_error(gsb, -ENXIO); + return AE_OK; +} + +static acpi_status san_rqst(struct san_data *d, struct gsb_buffer *buffer) +{ + u8 rspbuf[SAN_GSB_MAX_RESPONSE]; + struct gsb_data_rqsx *gsb_rqst; + struct ssam_request rqst; + struct ssam_response rsp; + int status = 0; + + gsb_rqst = san_validate_rqsx(d->dev, "RQST", buffer); + if (!gsb_rqst) + return AE_OK; + + rqst.target_category = gsb_rqst->tc; + rqst.target_id = gsb_rqst->tid; + rqst.command_id = gsb_rqst->cid; + rqst.instance_id = gsb_rqst->iid; + rqst.flags = gsb_rqst->snc ? SSAM_REQUEST_HAS_RESPONSE : 0; + rqst.length = get_unaligned(&gsb_rqst->cdl); + rqst.payload = &gsb_rqst->pld[0]; + + rsp.capacity = ARRAY_SIZE(rspbuf); + rsp.length = 0; + rsp.pointer = &rspbuf[0]; + + /* Handle suspended device. */ + if (d->dev->power.is_suspended) { + dev_warn(d->dev, "rqst: device is suspended, not executing\n"); + return san_rqst_fixup_suspended(d, &rqst, buffer); + } + + status = __ssam_retry(ssam_request_sync_onstack, SAN_REQUEST_NUM_TRIES, + d->ctrl, &rqst, &rsp, SAN_GSB_MAX_RQSX_PAYLOAD); + + if (!status) { + gsb_rqsx_response_success(buffer, rsp.pointer, rsp.length); + } else { + dev_err(d->dev, "rqst: failed with error %d\n", status); + gsb_rqsx_response_error(buffer, status); + } + + return AE_OK; +} + +static acpi_status san_rqsg(struct san_data *d, struct gsb_buffer *buffer) +{ + struct gsb_data_rqsx *gsb_rqsg; + struct san_dgpu_event evt; + int status; + + gsb_rqsg = san_validate_rqsx(d->dev, "RQSG", buffer); + if (!gsb_rqsg) + return AE_OK; + + evt.category = gsb_rqsg->tc; + evt.target = gsb_rqsg->tid; + evt.command = gsb_rqsg->cid; + evt.instance = gsb_rqsg->iid; + evt.length = get_unaligned(&gsb_rqsg->cdl); + evt.payload = &gsb_rqsg->pld[0]; + + status = san_dgpu_notifier_call(&evt); + if (!status) { + gsb_rqsx_response_success(buffer, NULL, 0); + } else { + dev_err(d->dev, "rqsg: failed with error %d\n", status); + gsb_rqsx_response_error(buffer, status); + } + + return AE_OK; +} + +static acpi_status san_opreg_handler(u32 function, acpi_physical_address command, + u32 bits, u64 *value64, void *opreg_context, + void *region_context) +{ + struct san_data *d = to_san_data(opreg_context, info); + struct gsb_buffer *buffer = (struct gsb_buffer *)value64; + int accessor_type = (function & 0xFFFF0000) >> 16; + + if (command != SAN_GSB_COMMAND) { + dev_warn(d->dev, "unsupported command: %#04llx\n", command); + return AE_OK; + } + + if (accessor_type != ACPI_GSB_ACCESS_ATTRIB_RAW_PROCESS) { + dev_err(d->dev, "invalid access type: %#04x\n", accessor_type); + return AE_OK; + } + + /* Buffer must have at least contain the command-value. */ + if (buffer->len == 0) { + dev_err(d->dev, "request-package too small\n"); + return AE_OK; + } + + switch (buffer->data.in.cv) { + case SAN_GSB_REQUEST_CV_RQST: + return san_rqst(d, buffer); + + case SAN_GSB_REQUEST_CV_ETWL: + return san_etwl(d, buffer); + + case SAN_GSB_REQUEST_CV_RQSG: + return san_rqsg(d, buffer); + + default: + dev_warn(d->dev, "unsupported SAN0 request (cv: %#04x)\n", + buffer->data.in.cv); + return AE_OK; + } +} + + +/* -- Driver setup. --------------------------------------------------------- */ + +static int san_events_register(struct platform_device *pdev) +{ + struct san_data *d = platform_get_drvdata(pdev); + int status; + + d->nf_bat.base.priority = 1; + d->nf_bat.base.fn = san_evt_bat_nf; + d->nf_bat.event.reg = SSAM_EVENT_REGISTRY_SAM; + d->nf_bat.event.id.target_category = SSAM_SSH_TC_BAT; + d->nf_bat.event.id.instance = 0; + d->nf_bat.event.mask = SSAM_EVENT_MASK_TARGET; + d->nf_bat.event.flags = SSAM_EVENT_SEQUENCED; + + d->nf_tmp.base.priority = 1; + d->nf_tmp.base.fn = san_evt_tmp_nf; + d->nf_tmp.event.reg = SSAM_EVENT_REGISTRY_SAM; + d->nf_tmp.event.id.target_category = SSAM_SSH_TC_TMP; + d->nf_tmp.event.id.instance = 0; + d->nf_tmp.event.mask = SSAM_EVENT_MASK_TARGET; + d->nf_tmp.event.flags = SSAM_EVENT_SEQUENCED; + + status = ssam_notifier_register(d->ctrl, &d->nf_bat); + if (status) + return status; + + status = ssam_notifier_register(d->ctrl, &d->nf_tmp); + if (status) + ssam_notifier_unregister(d->ctrl, &d->nf_bat); + + return status; +} + +static void san_events_unregister(struct platform_device *pdev) +{ + struct san_data *d = platform_get_drvdata(pdev); + + ssam_notifier_unregister(d->ctrl, &d->nf_bat); + ssam_notifier_unregister(d->ctrl, &d->nf_tmp); +} + +#define san_consumer_printk(level, dev, handle, fmt, ...) \ +do { \ + char *path = ""; \ + struct acpi_buffer buffer = { \ + .length = ACPI_ALLOCATE_BUFFER, \ + .pointer = NULL, \ + }; \ + \ + if (ACPI_SUCCESS(acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer))) \ + path = buffer.pointer; \ + \ + dev_##level(dev, "[%s]: " fmt, path, ##__VA_ARGS__); \ + kfree(buffer.pointer); \ +} while (0) + +#define san_consumer_dbg(dev, handle, fmt, ...) \ + san_consumer_printk(dbg, dev, handle, fmt, ##__VA_ARGS__) + +#define san_consumer_warn(dev, handle, fmt, ...) \ + san_consumer_printk(warn, dev, handle, fmt, ##__VA_ARGS__) + +static bool is_san_consumer(struct platform_device *pdev, acpi_handle handle) +{ + struct acpi_handle_list dep_devices; + acpi_handle supplier = ACPI_HANDLE(&pdev->dev); + acpi_status status; + int i; + + if (!acpi_has_method(handle, "_DEP")) + return false; + + status = acpi_evaluate_reference(handle, "_DEP", NULL, &dep_devices); + if (ACPI_FAILURE(status)) { + san_consumer_dbg(&pdev->dev, handle, "failed to evaluate _DEP\n"); + return false; + } + + for (i = 0; i < dep_devices.count; i++) { + if (dep_devices.handles[i] == supplier) + return true; + } + + return false; +} + +static acpi_status san_consumer_setup(acpi_handle handle, u32 lvl, + void *context, void **rv) +{ + const u32 flags = DL_FLAG_PM_RUNTIME | DL_FLAG_AUTOREMOVE_SUPPLIER; + struct platform_device *pdev = context; + struct acpi_device *adev; + struct device_link *link; + + if (!is_san_consumer(pdev, handle)) + return AE_OK; + + /* Ignore ACPI devices that are not present. */ + if (acpi_bus_get_device(handle, &adev) != 0) + return AE_OK; + + san_consumer_dbg(&pdev->dev, handle, "creating device link\n"); + + /* Try to set up device links, ignore but log errors. */ + link = device_link_add(&adev->dev, &pdev->dev, flags); + if (!link) { + san_consumer_warn(&pdev->dev, handle, "failed to create device link\n"); + return AE_OK; + } + + return AE_OK; +} + +static int san_consumer_links_setup(struct platform_device *pdev) +{ + acpi_status status; + + status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT, + ACPI_UINT32_MAX, san_consumer_setup, NULL, + pdev, NULL); + + return status ? -EFAULT : 0; +} + +static int san_probe(struct platform_device *pdev) +{ + acpi_handle san = ACPI_HANDLE(&pdev->dev); + struct ssam_controller *ctrl; + struct san_data *data; + acpi_status astatus; + int status; + + ctrl = ssam_client_bind(&pdev->dev); + if (IS_ERR(ctrl)) + return PTR_ERR(ctrl) == -ENODEV ? -EPROBE_DEFER : PTR_ERR(ctrl); + + status = san_consumer_links_setup(pdev); + if (status) + return status; + + data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL); + if (!data) + return -ENOMEM; + + data->dev = &pdev->dev; + data->ctrl = ctrl; + + platform_set_drvdata(pdev, data); + + astatus = acpi_install_address_space_handler(san, ACPI_ADR_SPACE_GSBUS, + &san_opreg_handler, NULL, + &data->info); + if (ACPI_FAILURE(astatus)) + return -ENXIO; + + status = san_events_register(pdev); + if (status) + goto err_enable_events; + + status = san_set_rqsg_interface_device(&pdev->dev); + if (status) + goto err_install_dev; + + acpi_walk_dep_device_list(san); + return 0; + +err_install_dev: + san_events_unregister(pdev); +err_enable_events: + acpi_remove_address_space_handler(san, ACPI_ADR_SPACE_GSBUS, + &san_opreg_handler); + return status; +} + +static int san_remove(struct platform_device *pdev) +{ + acpi_handle san = ACPI_HANDLE(&pdev->dev); + + san_set_rqsg_interface_device(NULL); + acpi_remove_address_space_handler(san, ACPI_ADR_SPACE_GSBUS, + &san_opreg_handler); + san_events_unregister(pdev); + + /* + * We have unregistered our event sources. Now we need to ensure that + * all delayed works they may have spawned are run to completion. + */ + flush_scheduled_work(); + + return 0; +} + +static const struct acpi_device_id san_match[] = { + { "MSHW0091" }, + { }, +}; +MODULE_DEVICE_TABLE(acpi, san_match); + +static struct platform_driver surface_acpi_notify = { + .probe = san_probe, + .remove = san_remove, + .driver = { + .name = "surface_acpi_notify", + .acpi_match_table = san_match, + .probe_type = PROBE_PREFER_ASYNCHRONOUS, + }, +}; +module_platform_driver(surface_acpi_notify); + +MODULE_AUTHOR("Maximilian Luz "); +MODULE_DESCRIPTION("Surface ACPI Notify driver for Surface System Aggregator Module"); +MODULE_LICENSE("GPL"); -- cgit v1.2.3 From d26cbdd27f8c4ff2f3df227a8bc5782697ecce51 Mon Sep 17 00:00:00 2001 From: Colin Ian King Date: Mon, 11 Jan 2021 14:46:48 +0000 Subject: platform/surface: fix potential integer overflow on shift of a int The left shift of int 32 bit integer constant 1 is evaluated using 32 bit arithmetic and then passed as a 64 bit function argument. In the case where func is 32 or more this can lead to an oveflow. Avoid this by shifting using the BIT_ULL macro instead. Addresses-Coverity: ("Unintentional integer overflow") Fixes: fc00bc8ac1da ("platform/surface: Add Surface ACPI Notify driver") Signed-off-by: Colin Ian King Reviewed-by: Maximilian Luz Link: https://lore.kernel.org/r/20210111144648.20498-1-colin.king@canonical.com Signed-off-by: Hans de Goede --- drivers/platform/surface/surface_acpi_notify.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/platform/surface') diff --git a/drivers/platform/surface/surface_acpi_notify.c b/drivers/platform/surface/surface_acpi_notify.c index 8cd67a669c86..ef9c1f8e8336 100644 --- a/drivers/platform/surface/surface_acpi_notify.c +++ b/drivers/platform/surface/surface_acpi_notify.c @@ -188,7 +188,7 @@ static int san_acpi_notify_event(struct device *dev, u64 func, union acpi_object *obj; int status = 0; - if (!acpi_check_dsm(san, &SAN_DSM_UUID, SAN_DSM_REVISION, 1 << func)) + if (!acpi_check_dsm(san, &SAN_DSM_UUID, SAN_DSM_REVISION, BIT_ULL(func))) return 0; dev_dbg(dev, "notify event %#04llx\n", func); -- cgit v1.2.3 From a403c1dfcf9fb73a4a362f14ca1c1f04662c49e0 Mon Sep 17 00:00:00 2001 From: Maximilian Luz Date: Mon, 11 Jan 2021 16:48:50 +0100 Subject: platform/surface: aggregator_cdev: Fix access of uninitialized variables When copy_struct_from_user() in ssam_cdev_request() fails, we directly jump to the 'out' label. In this case, however 'spec' and 'rsp' are not initialized, but we still access fields of those variables. Fix this by initializing them at the time of their declaration. Reported-by: Colin Ian King Fixes: 178f6ab77e61 ("platform/surface: Add Surface Aggregator user-space interface") Addresses-Coverity: ("Uninitialized pointer read") Signed-off-by: Maximilian Luz Link: https://lore.kernel.org/r/20210111154851.325404-2-luzmaximilian@gmail.com Signed-off-by: Hans de Goede --- drivers/platform/surface/surface_aggregator_cdev.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'drivers/platform/surface') diff --git a/drivers/platform/surface/surface_aggregator_cdev.c b/drivers/platform/surface/surface_aggregator_cdev.c index 340d15b148b9..979340cdd9de 100644 --- a/drivers/platform/surface/surface_aggregator_cdev.c +++ b/drivers/platform/surface/surface_aggregator_cdev.c @@ -66,8 +66,8 @@ static long ssam_cdev_request(struct ssam_cdev *cdev, unsigned long arg) { struct ssam_cdev_request __user *r; struct ssam_cdev_request rqst; - struct ssam_request spec; - struct ssam_response rsp; + struct ssam_request spec = {}; + struct ssam_response rsp = {}; const void __user *plddata; void __user *rspdata; int status = 0, ret = 0, tmp; -- cgit v1.2.3 From e94a26504f41b2ad33ea1473d32506b01bf6693a Mon Sep 17 00:00:00 2001 From: Maximilian Luz Date: Mon, 11 Jan 2021 16:48:51 +0100 Subject: platform/surface: aggregator_cdev: Add comments regarding unchecked allocation size CI static analysis complains about the allocation size in payload and response buffers being unchecked. In general, these allocations should be safe as the user-input is u16 and thus limited to U16_MAX, which is only slightly larger than the theoretical maximum imposed by the underlying SSH protocol. All bounds on these values required by the underlying protocol are enforced in ssam_request_sync() (or rather the functions called by it), thus bounds here are only relevant for allocation. Add comments explaining that this should be safe. Reported-by: Colin Ian King Fixes: 178f6ab77e61 ("platform/surface: Add Surface Aggregator user-space interface") Addresses-Coverity: ("Untrusted allocation size") Signed-off-by: Maximilian Luz Link: https://lore.kernel.org/r/20210111154851.325404-3-luzmaximilian@gmail.com Signed-off-by: Hans de Goede --- drivers/platform/surface/surface_aggregator_cdev.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) (limited to 'drivers/platform/surface') diff --git a/drivers/platform/surface/surface_aggregator_cdev.c b/drivers/platform/surface/surface_aggregator_cdev.c index 979340cdd9de..79e28fab7e40 100644 --- a/drivers/platform/surface/surface_aggregator_cdev.c +++ b/drivers/platform/surface/surface_aggregator_cdev.c @@ -106,6 +106,15 @@ static long ssam_cdev_request(struct ssam_cdev *cdev, unsigned long arg) goto out; } + /* + * Note: spec.length is limited to U16_MAX bytes via struct + * ssam_cdev_request. This is slightly larger than the + * theoretical maximum (SSH_COMMAND_MAX_PAYLOAD_SIZE) of the + * underlying protocol (note that nothing remotely this size + * should ever be allocated in any normal case). This size is + * validated later in ssam_request_sync(), for allocation the + * bound imposed by u16 should be enough. + */ spec.payload = kzalloc(spec.length, GFP_KERNEL); if (!spec.payload) { ret = -ENOMEM; @@ -125,6 +134,16 @@ static long ssam_cdev_request(struct ssam_cdev *cdev, unsigned long arg) goto out; } + /* + * Note: rsp.capacity is limited to U16_MAX bytes via struct + * ssam_cdev_request. This is slightly larger than the + * theoretical maximum (SSH_COMMAND_MAX_PAYLOAD_SIZE) of the + * underlying protocol (note that nothing remotely this size + * should ever be allocated in any normal case). In later use, + * this capacity does not have to be strictly bounded, as it + * is only used as an output buffer to be written to. For + * allocation the bound imposed by u16 should be enough. + */ rsp.pointer = kzalloc(rsp.capacity, GFP_KERNEL); if (!rsp.pointer) { ret = -ENOMEM; -- cgit v1.2.3 From 025fe94b63dd2b781788eaff35ab2663cfef749a Mon Sep 17 00:00:00 2001 From: Mauro Carvalho Chehab Date: Thu, 14 Jan 2021 09:04:52 +0100 Subject: platform/surface: aggregator: fix a kernel-doc markup A function has a different name between their prototype and its kernel-doc markup: ../drivers/platform/surface/aggregator/ssh_request_layer.c:1065: warning: expecting prototype for ssh_rtl_tx_start(). Prototype was for ssh_rtl_start() instead Signed-off-by: Mauro Carvalho Chehab Reviewed-by: Maximilian Luz Link: https://lore.kernel.org/r/4a6bf33cfbd06654d78294127f2b6d354d073089.1610610937.git.mchehab+huawei@kernel.org Signed-off-by: Hans de Goede --- drivers/platform/surface/aggregator/ssh_request_layer.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/platform/surface') diff --git a/drivers/platform/surface/aggregator/ssh_request_layer.c b/drivers/platform/surface/aggregator/ssh_request_layer.c index bb1c862411a2..25db4d638cfa 100644 --- a/drivers/platform/surface/aggregator/ssh_request_layer.c +++ b/drivers/platform/surface/aggregator/ssh_request_layer.c @@ -1056,7 +1056,7 @@ void ssh_rtl_destroy(struct ssh_rtl *rtl) } /** - * ssh_rtl_tx_start() - Start request transmitter and receiver. + * ssh_rtl_start() - Start request transmitter and receiver. * @rtl: The request transport layer. * * Return: Returns zero on success, a negative error code on failure. -- cgit v1.2.3 From e5da18d3e67dbc326205fb179f0e5085372537dd Mon Sep 17 00:00:00 2001 From: Maximilian Luz Date: Thu, 14 Jan 2021 16:08:26 +0100 Subject: platform/surface: aggregator: Fix kernel-doc references Both, ssh_rtl_rx_start() and ssh_rtl_tx_start() functions, do not exist and have been consolidated into ssh_rtl_start(). Nevertheless, kernel-doc references the former functions. Replace those references with references to ssh_rtl_start(). Signed-off-by: Maximilian Luz Link: https://lore.kernel.org/r/20210114150826.19109-1-luzmaximilian@gmail.com Signed-off-by: Hans de Goede --- drivers/platform/surface/aggregator/ssh_request_layer.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) (limited to 'drivers/platform/surface') diff --git a/drivers/platform/surface/aggregator/ssh_request_layer.c b/drivers/platform/surface/aggregator/ssh_request_layer.c index 25db4d638cfa..52a83a8fcf82 100644 --- a/drivers/platform/surface/aggregator/ssh_request_layer.c +++ b/drivers/platform/surface/aggregator/ssh_request_layer.c @@ -1004,9 +1004,8 @@ int ssh_request_init(struct ssh_request *rqst, enum ssam_request_flags flags, * * Initializes the given request transport layer and associated packet * transport layer. Transmitter and receiver threads must be started - * separately via ssh_rtl_tx_start() and ssh_rtl_rx_start(), after the - * request-layer has been initialized and the lower-level serial device layer - * has been set up. + * separately via ssh_rtl_start(), after the request-layer has been + * initialized and the lower-level serial device layer has been set up. * * Return: Returns zero on success and a nonzero error code on failure. */ -- cgit v1.2.3 From 2691d0ae668ab9d9f3f275ac6ed6029862780084 Mon Sep 17 00:00:00 2001 From: Maximilian Luz Date: Tue, 26 Jan 2021 18:22:02 +0100 Subject: platform/surface: aggregator: Fix braces in if condition with unlikely() macro The braces of the unlikely() macro inside the if condition only cover the subtraction part, not the whole statement. This causes the result of the subtraction to be converted to zero or one. While that still works in this context, it causes static analysis tools to complain (and is just plain wrong). Fix the bracket placement and, while at it, simplify the if-condition. Also add a comment to the if-condition explaining what we expect the result to be and what happens on the failure path, as it seems to have caused a bit of confusion. This commit should not cause any difference in behavior or generated code. Reported-by: Dan Carpenter Fixes: c167b9c7e3d6 ("platform/surface: Add Surface Aggregator subsystem") Signed-off-by: Maximilian Luz Link: https://lore.kernel.org/r/20210126172202.1428367-1-luzmaximilian@gmail.com Signed-off-by: Hans de Goede --- .../platform/surface/aggregator/ssh_packet_layer.c | 19 ++++++++++++++++++- 1 file changed, 18 insertions(+), 1 deletion(-) (limited to 'drivers/platform/surface') diff --git a/drivers/platform/surface/aggregator/ssh_packet_layer.c b/drivers/platform/surface/aggregator/ssh_packet_layer.c index 74f0faaa2b27..583315db8b02 100644 --- a/drivers/platform/surface/aggregator/ssh_packet_layer.c +++ b/drivers/platform/surface/aggregator/ssh_packet_layer.c @@ -1694,7 +1694,24 @@ static size_t ssh_ptl_rx_eval(struct ssh_ptl *ptl, struct ssam_span *source) /* Find SYN. */ syn_found = sshp_find_syn(source, &aligned); - if (unlikely(aligned.ptr - source->ptr) > 0) { + if (unlikely(aligned.ptr != source->ptr)) { + /* + * We expect aligned.ptr == source->ptr. If this is not the + * case, then aligned.ptr > source->ptr and we've encountered + * some unexpected data where we'd expect the start of a new + * message (i.e. the SYN sequence). + * + * This can happen when a CRC check for the previous message + * failed and we start actively searching for the next one + * (via the call to sshp_find_syn() above), or the first bytes + * of a message got dropped or corrupted. + * + * In any case, we issue a warning, send a NAK to the EC to + * request re-transmission of any data we haven't acknowledged + * yet, and finally, skip everything up to the next SYN + * sequence. + */ + ptl_warn(ptl, "rx: parser: invalid start of frame, skipping\n"); /* -- cgit v1.2.3 From f807f4b7b32db00fc8622289644362e0695989bb Mon Sep 17 00:00:00 2001 From: Hans de Goede Date: Thu, 4 Feb 2021 12:38:48 +0100 Subject: platform/surface: surface3-wmi: Fix variable 'status' set but not used compiler warning Explicitly check the status rather then relying on output.pointer staying NULL on an error. This silences the following compiler warning: drivers/platform/surface/surface3-wmi.c:60:14: warning: variable 'status' set but not used [-Wunused-but-set-variable] Reported-by: kernel test robot Reviewed-by: Maximilian Luz Signed-off-by: Hans de Goede Link: https://lore.kernel.org/r/20210204113848.105994-1-hdegoede@redhat.com --- drivers/platform/surface/surface3-wmi.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'drivers/platform/surface') diff --git a/drivers/platform/surface/surface3-wmi.c b/drivers/platform/surface/surface3-wmi.c index 130b6f52a600..fcd1d4fb94d5 100644 --- a/drivers/platform/surface/surface3-wmi.c +++ b/drivers/platform/surface/surface3-wmi.c @@ -57,12 +57,16 @@ static DEFINE_MUTEX(s3_wmi_lock); static int s3_wmi_query_block(const char *guid, int instance, int *ret) { struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL }; + union acpi_object *obj = NULL; acpi_status status; - union acpi_object *obj; int error = 0; mutex_lock(&s3_wmi_lock); status = wmi_query_block(guid, instance, &output); + if (ACPI_FAILURE(status)) { + error = -EIO; + goto out_free_unlock; + } obj = output.pointer; -- cgit v1.2.3 From bd69bcce4aa089435e2891222236b1cb20395bec Mon Sep 17 00:00:00 2001 From: Maximilian Luz Date: Fri, 5 Feb 2021 02:26:57 +0100 Subject: platform/surface: Add Surface Hot-Plug driver Some Surface Book 2 and 3 models have a discrete GPU (dGPU) that is hot-pluggable. On those devices, the dGPU is contained in the base, which can be separated from the tablet part (containing CPU and touchscreen) while the device is running. It (in general) is presented as/behaves like a standard PCIe hot-plug capable device, however, this device can also be put into D3cold. In D3cold, the device itself is turned off and can thus not submit any standard PCIe hot-plug events. To properly detect hot-(un)plugging while the dGPU is in D3cold, out-of-band signaling is required. Without this, the device state will only get updated during the next bus-check, eg. via a manually issued lspci call. This commit adds a driver to handle out-of-band PCIe hot-(un)plug events on Microsoft Surface devices. On those devices, said events can be detected via GPIO interrupts, which are then forwarded to the corresponding ACPI DSM calls by this driver. The DSM then takes care of issuing the appropriate bus-/device-check, causing the PCI core to properly pick up the device change. Signed-off-by: Maximilian Luz Link: https://lore.kernel.org/r/20210205012657.1951753-1-luzmaximilian@gmail.com Signed-off-by: Hans de Goede --- drivers/platform/surface/Kconfig | 19 ++ drivers/platform/surface/Makefile | 1 + drivers/platform/surface/surface_hotplug.c | 282 +++++++++++++++++++++++++++++ 3 files changed, 302 insertions(+) create mode 100644 drivers/platform/surface/surface_hotplug.c (limited to 'drivers/platform/surface') diff --git a/drivers/platform/surface/Kconfig b/drivers/platform/surface/Kconfig index 83b0a4c7b352..0847b2dc97bf 100644 --- a/drivers/platform/surface/Kconfig +++ b/drivers/platform/surface/Kconfig @@ -86,6 +86,25 @@ config SURFACE_GPE accordingly. It is required on those devices to allow wake-ups from suspend by opening the lid. +config SURFACE_HOTPLUG + tristate "Surface Hot-Plug Driver" + depends on GPIOLIB + help + Driver for out-of-band hot-plug event signaling on Microsoft Surface + devices with hot-pluggable PCIe cards. + + This driver is used on Surface Book (2 and 3) devices with a + hot-pluggable discrete GPU (dGPU). When not in use, the dGPU on those + devices can enter D3cold, which prevents in-band (standard) PCIe + hot-plug signaling. Thus, without this driver, detaching the base + containing the dGPU will not correctly update the state of the + corresponding PCIe device if it is in D3cold. This driver adds support + for out-of-band hot-plug notifications, ensuring that the device state + is properly updated even when the device in question is in D3cold. + + Select M or Y here, if you want to (fully) support hot-plugging of + dGPU devices on the Surface Book 2 and/or 3 during D3cold. + config SURFACE_PRO3_BUTTON tristate "Power/home/volume buttons driver for Microsoft Surface Pro 3/4 tablet" depends on INPUT diff --git a/drivers/platform/surface/Makefile b/drivers/platform/surface/Makefile index 3eb971006877..990424c5f0c9 100644 --- a/drivers/platform/surface/Makefile +++ b/drivers/platform/surface/Makefile @@ -11,4 +11,5 @@ obj-$(CONFIG_SURFACE_ACPI_NOTIFY) += surface_acpi_notify.o obj-$(CONFIG_SURFACE_AGGREGATOR) += aggregator/ obj-$(CONFIG_SURFACE_AGGREGATOR_CDEV) += surface_aggregator_cdev.o obj-$(CONFIG_SURFACE_GPE) += surface_gpe.o +obj-$(CONFIG_SURFACE_HOTPLUG) += surface_hotplug.o obj-$(CONFIG_SURFACE_PRO3_BUTTON) += surfacepro3_button.o diff --git a/drivers/platform/surface/surface_hotplug.c b/drivers/platform/surface/surface_hotplug.c new file mode 100644 index 000000000000..cfcc15cfbacb --- /dev/null +++ b/drivers/platform/surface/surface_hotplug.c @@ -0,0 +1,282 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Surface Book (2 and later) hot-plug driver. + * + * Surface Book devices (can) have a hot-pluggable discrete GPU (dGPU). This + * driver is responsible for out-of-band hot-plug event signaling on these + * devices. It is specifically required when the hot-plug device is in D3cold + * and can thus not generate PCIe hot-plug events itself. + * + * Event signaling is handled via ACPI, which will generate the appropriate + * device-check notifications to be picked up by the PCIe hot-plug driver. + * + * Copyright (C) 2019-2021 Maximilian Luz + */ + +#include +#include +#include +#include +#include +#include +#include + +static const struct acpi_gpio_params shps_base_presence_int = { 0, 0, false }; +static const struct acpi_gpio_params shps_base_presence = { 1, 0, false }; +static const struct acpi_gpio_params shps_device_power_int = { 2, 0, false }; +static const struct acpi_gpio_params shps_device_power = { 3, 0, false }; +static const struct acpi_gpio_params shps_device_presence_int = { 4, 0, false }; +static const struct acpi_gpio_params shps_device_presence = { 5, 0, false }; + +static const struct acpi_gpio_mapping shps_acpi_gpios[] = { + { "base_presence-int-gpio", &shps_base_presence_int, 1 }, + { "base_presence-gpio", &shps_base_presence, 1 }, + { "device_power-int-gpio", &shps_device_power_int, 1 }, + { "device_power-gpio", &shps_device_power, 1 }, + { "device_presence-int-gpio", &shps_device_presence_int, 1 }, + { "device_presence-gpio", &shps_device_presence, 1 }, + { }, +}; + +/* 5515a847-ed55-4b27-8352-cd320e10360a */ +static const guid_t shps_dsm_guid = + GUID_INIT(0x5515a847, 0xed55, 0x4b27, 0x83, 0x52, 0xcd, 0x32, 0x0e, 0x10, 0x36, 0x0a); + +#define SHPS_DSM_REVISION 1 + +enum shps_dsm_fn { + SHPS_DSM_FN_PCI_NUM_ENTRIES = 0x01, + SHPS_DSM_FN_PCI_GET_ENTRIES = 0x02, + SHPS_DSM_FN_IRQ_BASE_PRESENCE = 0x03, + SHPS_DSM_FN_IRQ_DEVICE_POWER = 0x04, + SHPS_DSM_FN_IRQ_DEVICE_PRESENCE = 0x05, +}; + +enum shps_irq_type { + /* NOTE: Must be in order of enum shps_dsm_fn above. */ + SHPS_IRQ_TYPE_BASE_PRESENCE = 0, + SHPS_IRQ_TYPE_DEVICE_POWER = 1, + SHPS_IRQ_TYPE_DEVICE_PRESENCE = 2, + SHPS_NUM_IRQS, +}; + +static const char *const shps_gpio_names[] = { + [SHPS_IRQ_TYPE_BASE_PRESENCE] = "base_presence", + [SHPS_IRQ_TYPE_DEVICE_POWER] = "device_power", + [SHPS_IRQ_TYPE_DEVICE_PRESENCE] = "device_presence", +}; + +struct shps_device { + struct mutex lock[SHPS_NUM_IRQS]; /* Protects update in shps_dsm_notify_irq() */ + struct gpio_desc *gpio[SHPS_NUM_IRQS]; + unsigned int irq[SHPS_NUM_IRQS]; +}; + +#define SHPS_IRQ_NOT_PRESENT ((unsigned int)-1) + +static enum shps_dsm_fn shps_dsm_fn_for_irq(enum shps_irq_type type) +{ + return SHPS_DSM_FN_IRQ_BASE_PRESENCE + type; +} + +static void shps_dsm_notify_irq(struct platform_device *pdev, enum shps_irq_type type) +{ + struct shps_device *sdev = platform_get_drvdata(pdev); + acpi_handle handle = ACPI_HANDLE(&pdev->dev); + union acpi_object *result; + union acpi_object param; + int value; + + mutex_lock(&sdev->lock[type]); + + value = gpiod_get_value_cansleep(sdev->gpio[type]); + if (value < 0) { + mutex_unlock(&sdev->lock[type]); + dev_err(&pdev->dev, "failed to get gpio: %d (irq=%d)\n", type, value); + return; + } + + dev_dbg(&pdev->dev, "IRQ notification via DSM (irq=%d, value=%d)\n", type, value); + + param.type = ACPI_TYPE_INTEGER; + param.integer.value = value; + + result = acpi_evaluate_dsm(handle, &shps_dsm_guid, SHPS_DSM_REVISION, + shps_dsm_fn_for_irq(type), ¶m); + + if (!result) { + dev_err(&pdev->dev, "IRQ notification via DSM failed (irq=%d, gpio=%d)\n", + type, value); + + } else if (result->type != ACPI_TYPE_BUFFER) { + dev_err(&pdev->dev, + "IRQ notification via DSM failed: unexpected result type (irq=%d, gpio=%d)\n", + type, value); + + } else if (result->buffer.length != 1 || result->buffer.pointer[0] != 0) { + dev_err(&pdev->dev, + "IRQ notification via DSM failed: unexpected result value (irq=%d, gpio=%d)\n", + type, value); + } + + mutex_unlock(&sdev->lock[type]); + + if (result) + ACPI_FREE(result); +} + +static irqreturn_t shps_handle_irq(int irq, void *data) +{ + struct platform_device *pdev = data; + struct shps_device *sdev = platform_get_drvdata(pdev); + int type; + + /* Figure out which IRQ we're handling. */ + for (type = 0; type < SHPS_NUM_IRQS; type++) + if (irq == sdev->irq[type]) + break; + + /* We should have found our interrupt, if not: this is a bug. */ + if (WARN(type >= SHPS_NUM_IRQS, "invalid IRQ number: %d\n", irq)) + return IRQ_HANDLED; + + /* Forward interrupt to ACPI via DSM. */ + shps_dsm_notify_irq(pdev, type); + return IRQ_HANDLED; +} + +static int shps_setup_irq(struct platform_device *pdev, enum shps_irq_type type) +{ + unsigned long flags = IRQF_ONESHOT | IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING; + struct shps_device *sdev = platform_get_drvdata(pdev); + struct gpio_desc *gpiod; + acpi_handle handle = ACPI_HANDLE(&pdev->dev); + const char *irq_name; + const int dsm = shps_dsm_fn_for_irq(type); + int status, irq; + + /* + * Only set up interrupts that we actually need: The Surface Book 3 + * does not have a DSM for base presence, so don't set up an interrupt + * for that. + */ + if (!acpi_check_dsm(handle, &shps_dsm_guid, SHPS_DSM_REVISION, BIT(dsm))) { + dev_dbg(&pdev->dev, "IRQ notification via DSM not present (irq=%d)\n", type); + return 0; + } + + gpiod = devm_gpiod_get(&pdev->dev, shps_gpio_names[type], GPIOD_ASIS); + if (IS_ERR(gpiod)) + return PTR_ERR(gpiod); + + irq = gpiod_to_irq(gpiod); + if (irq < 0) + return irq; + + irq_name = devm_kasprintf(&pdev->dev, GFP_KERNEL, "shps-irq-%d", type); + if (!irq_name) + return -ENOMEM; + + status = devm_request_threaded_irq(&pdev->dev, irq, NULL, shps_handle_irq, + flags, irq_name, pdev); + if (status) + return status; + + dev_dbg(&pdev->dev, "set up irq %d as type %d\n", irq, type); + + sdev->gpio[type] = gpiod; + sdev->irq[type] = irq; + + return 0; +} + +static int surface_hotplug_remove(struct platform_device *pdev) +{ + struct shps_device *sdev = platform_get_drvdata(pdev); + int i; + + /* Ensure that IRQs have been fully handled and won't trigger any more. */ + for (i = 0; i < SHPS_NUM_IRQS; i++) { + if (sdev->irq[i] != SHPS_IRQ_NOT_PRESENT) + disable_irq(sdev->irq[i]); + + mutex_destroy(&sdev->lock[i]); + } + + return 0; +} + +static int surface_hotplug_probe(struct platform_device *pdev) +{ + struct shps_device *sdev; + int status, i; + + /* + * The MSHW0153 device is also present on the Surface Laptop 3, + * however that doesn't have a hot-pluggable PCIe device. It also + * doesn't have any GPIO interrupts/pins under the MSHW0153, so filter + * it out here. + */ + if (gpiod_count(&pdev->dev, NULL) < 0) + return -ENODEV; + + status = devm_acpi_dev_add_driver_gpios(&pdev->dev, shps_acpi_gpios); + if (status) + return status; + + sdev = devm_kzalloc(&pdev->dev, sizeof(*sdev), GFP_KERNEL); + if (!sdev) + return -ENOMEM; + + platform_set_drvdata(pdev, sdev); + + /* + * Initialize IRQs so that we can safely call surface_hotplug_remove() + * on errors. + */ + for (i = 0; i < SHPS_NUM_IRQS; i++) + sdev->irq[i] = SHPS_IRQ_NOT_PRESENT; + + /* Set up IRQs. */ + for (i = 0; i < SHPS_NUM_IRQS; i++) { + mutex_init(&sdev->lock[i]); + + status = shps_setup_irq(pdev, i); + if (status) { + dev_err(&pdev->dev, "failed to set up IRQ %d: %d\n", i, status); + goto err; + } + } + + /* Ensure everything is up-to-date. */ + for (i = 0; i < SHPS_NUM_IRQS; i++) + if (sdev->irq[i] != SHPS_IRQ_NOT_PRESENT) + shps_dsm_notify_irq(pdev, i); + + return 0; + +err: + surface_hotplug_remove(pdev); + return status; +} + +static const struct acpi_device_id surface_hotplug_acpi_match[] = { + { "MSHW0153", 0 }, + { }, +}; +MODULE_DEVICE_TABLE(acpi, surface_hotplug_acpi_match); + +static struct platform_driver surface_hotplug_driver = { + .probe = surface_hotplug_probe, + .remove = surface_hotplug_remove, + .driver = { + .name = "surface_hotplug", + .acpi_match_table = surface_hotplug_acpi_match, + .probe_type = PROBE_PREFER_ASYNCHRONOUS, + }, +}; +module_platform_driver(surface_hotplug_driver); + +MODULE_AUTHOR("Maximilian Luz "); +MODULE_DESCRIPTION("Surface Hot-Plug Signaling Driver for Surface Book Devices"); +MODULE_LICENSE("GPL"); -- cgit v1.2.3 From 86eb98cb4a911631874c43309f39aa0003ad0106 Mon Sep 17 00:00:00 2001 From: Maximilian Luz Date: Thu, 11 Feb 2021 13:41:49 +0100 Subject: platform/surface: aggregator: Fix access of unaligned value The raw message frame length is unaligned and explicitly marked as little endian. It should not be accessed without the appropriate accessor functions. Fix this. Note that payload.len already contains the correct length after parsing via sshp_parse_frame(), so we can simply use that instead. Reported-by: kernel-test-robot Fixes: c167b9c7e3d6 ("platform/surface: Add Surface Aggregator subsystem") Signed-off-by: Maximilian Luz Acked-by: Mark Gross Reviewed-by: Andy Shevchenko Link: https://lore.kernel.org/r/20210211124149.2439007-1-luzmaximilian@gmail.com Signed-off-by: Hans de Goede --- drivers/platform/surface/aggregator/ssh_packet_layer.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/platform/surface') diff --git a/drivers/platform/surface/aggregator/ssh_packet_layer.c b/drivers/platform/surface/aggregator/ssh_packet_layer.c index 583315db8b02..15d96eac6811 100644 --- a/drivers/platform/surface/aggregator/ssh_packet_layer.c +++ b/drivers/platform/surface/aggregator/ssh_packet_layer.c @@ -1774,7 +1774,7 @@ static size_t ssh_ptl_rx_eval(struct ssh_ptl *ptl, struct ssam_span *source) break; } - return aligned.ptr - source->ptr + SSH_MESSAGE_LENGTH(frame->len); + return aligned.ptr - source->ptr + SSH_MESSAGE_LENGTH(payload.len); } static int ssh_ptl_rx_threadfn(void *data) -- cgit v1.2.3