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authorRafael J. Wysocki <rjw@sisk.pl>2011-10-07 23:17:07 +0200
committerRafael J. Wysocki <rjw@sisk.pl>2011-10-07 23:17:07 +0200
commit9696cc90071e3660ec02a3728acdedb68afdce4c (patch)
tree99783d31dd42262c29346c92760f7896c3d81cb6 /drivers/base
parentc28b56b1d46b1bbb1be33c8f2632a88b0de1ef68 (diff)
parente3cba3243eb853a052613c804dea033bc4c9cf2d (diff)
Merge branch 'pm-qos' into pm-for-linus
* pm-qos: PM / QoS: Update Documentation for the pm_qos and dev_pm_qos frameworks PM / QoS: Add function dev_pm_qos_read_value() (v3) PM QoS: Add global notification mechanism for device constraints PM QoS: Implement per-device PM QoS constraints PM QoS: Generalize and export constraints management code PM QoS: Reorganize data structs PM QoS: Code reorganization PM QoS: Minor clean-ups PM QoS: Move and rename the implementation files
Diffstat (limited to 'drivers/base')
-rw-r--r--drivers/base/power/Makefile4
-rw-r--r--drivers/base/power/main.c3
-rw-r--r--drivers/base/power/power.h10
-rw-r--r--drivers/base/power/qos.c419
4 files changed, 433 insertions, 3 deletions
diff --git a/drivers/base/power/Makefile b/drivers/base/power/Makefile
index 6488ce12f586..81676dd17900 100644
--- a/drivers/base/power/Makefile
+++ b/drivers/base/power/Makefile
@@ -1,4 +1,4 @@
-obj-$(CONFIG_PM) += sysfs.o generic_ops.o common.o
+obj-$(CONFIG_PM) += sysfs.o generic_ops.o common.o qos.o
obj-$(CONFIG_PM_SLEEP) += main.o wakeup.o
obj-$(CONFIG_PM_RUNTIME) += runtime.o
obj-$(CONFIG_PM_TRACE_RTC) += trace.o
@@ -6,4 +6,4 @@ obj-$(CONFIG_PM_OPP) += opp.o
obj-$(CONFIG_PM_GENERIC_DOMAINS) += domain.o
obj-$(CONFIG_HAVE_CLK) += clock_ops.o
-ccflags-$(CONFIG_DEBUG_DRIVER) := -DDEBUG \ No newline at end of file
+ccflags-$(CONFIG_DEBUG_DRIVER) := -DDEBUG
diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
index a85459126bc6..c6291ab725a3 100644
--- a/drivers/base/power/main.c
+++ b/drivers/base/power/main.c
@@ -65,6 +65,7 @@ void device_pm_init(struct device *dev)
spin_lock_init(&dev->power.lock);
pm_runtime_init(dev);
INIT_LIST_HEAD(&dev->power.entry);
+ dev->power.power_state = PMSG_INVALID;
}
/**
@@ -96,6 +97,7 @@ void device_pm_add(struct device *dev)
dev_warn(dev, "parent %s should not be sleeping\n",
dev_name(dev->parent));
list_add_tail(&dev->power.entry, &dpm_list);
+ dev_pm_qos_constraints_init(dev);
mutex_unlock(&dpm_list_mtx);
}
@@ -109,6 +111,7 @@ void device_pm_remove(struct device *dev)
dev->bus ? dev->bus->name : "No Bus", dev_name(dev));
complete_all(&dev->power.completion);
mutex_lock(&dpm_list_mtx);
+ dev_pm_qos_constraints_destroy(dev);
list_del_init(&dev->power.entry);
mutex_unlock(&dpm_list_mtx);
device_wakeup_disable(dev);
diff --git a/drivers/base/power/power.h b/drivers/base/power/power.h
index f2a25f18fde7..9bf62323aaf3 100644
--- a/drivers/base/power/power.h
+++ b/drivers/base/power/power.h
@@ -1,3 +1,5 @@
+#include <linux/pm_qos.h>
+
#ifdef CONFIG_PM_RUNTIME
extern void pm_runtime_init(struct device *dev);
@@ -35,15 +37,21 @@ extern void device_pm_move_last(struct device *);
static inline void device_pm_init(struct device *dev)
{
spin_lock_init(&dev->power.lock);
+ dev->power.power_state = PMSG_INVALID;
pm_runtime_init(dev);
}
+static inline void device_pm_add(struct device *dev)
+{
+ dev_pm_qos_constraints_init(dev);
+}
+
static inline void device_pm_remove(struct device *dev)
{
+ dev_pm_qos_constraints_destroy(dev);
pm_runtime_remove(dev);
}
-static inline void device_pm_add(struct device *dev) {}
static inline void device_pm_move_before(struct device *deva,
struct device *devb) {}
static inline void device_pm_move_after(struct device *deva,
diff --git a/drivers/base/power/qos.c b/drivers/base/power/qos.c
new file mode 100644
index 000000000000..91e061417382
--- /dev/null
+++ b/drivers/base/power/qos.c
@@ -0,0 +1,419 @@
+/*
+ * Devices PM QoS constraints management
+ *
+ * Copyright (C) 2011 Texas Instruments, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ *
+ * This module exposes the interface to kernel space for specifying
+ * per-device PM QoS dependencies. It provides infrastructure for registration
+ * of:
+ *
+ * Dependents on a QoS value : register requests
+ * Watchers of QoS value : get notified when target QoS value changes
+ *
+ * This QoS design is best effort based. Dependents register their QoS needs.
+ * Watchers register to keep track of the current QoS needs of the system.
+ * Watchers can register different types of notification callbacks:
+ * . a per-device notification callback using the dev_pm_qos_*_notifier API.
+ * The notification chain data is stored in the per-device constraint
+ * data struct.
+ * . a system-wide notification callback using the dev_pm_qos_*_global_notifier
+ * API. The notification chain data is stored in a static variable.
+ *
+ * Note about the per-device constraint data struct allocation:
+ * . The per-device constraints data struct ptr is tored into the device
+ * dev_pm_info.
+ * . To minimize the data usage by the per-device constraints, the data struct
+ * is only allocated at the first call to dev_pm_qos_add_request.
+ * . The data is later free'd when the device is removed from the system.
+ * . A global mutex protects the constraints users from the data being
+ * allocated and free'd.
+ */
+
+#include <linux/pm_qos.h>
+#include <linux/spinlock.h>
+#include <linux/slab.h>
+#include <linux/device.h>
+#include <linux/mutex.h>
+
+
+static DEFINE_MUTEX(dev_pm_qos_mtx);
+
+static BLOCKING_NOTIFIER_HEAD(dev_pm_notifiers);
+
+/**
+ * dev_pm_qos_read_value - Get PM QoS constraint for a given device.
+ * @dev: Device to get the PM QoS constraint value for.
+ */
+s32 dev_pm_qos_read_value(struct device *dev)
+{
+ struct pm_qos_constraints *c;
+ unsigned long flags;
+ s32 ret = 0;
+
+ spin_lock_irqsave(&dev->power.lock, flags);
+
+ c = dev->power.constraints;
+ if (c)
+ ret = pm_qos_read_value(c);
+
+ spin_unlock_irqrestore(&dev->power.lock, flags);
+
+ return ret;
+}
+
+/*
+ * apply_constraint
+ * @req: constraint request to apply
+ * @action: action to perform add/update/remove, of type enum pm_qos_req_action
+ * @value: defines the qos request
+ *
+ * Internal function to update the constraints list using the PM QoS core
+ * code and if needed call the per-device and the global notification
+ * callbacks
+ */
+static int apply_constraint(struct dev_pm_qos_request *req,
+ enum pm_qos_req_action action, int value)
+{
+ int ret, curr_value;
+
+ ret = pm_qos_update_target(req->dev->power.constraints,
+ &req->node, action, value);
+
+ if (ret) {
+ /* Call the global callbacks if needed */
+ curr_value = pm_qos_read_value(req->dev->power.constraints);
+ blocking_notifier_call_chain(&dev_pm_notifiers,
+ (unsigned long)curr_value,
+ req);
+ }
+
+ return ret;
+}
+
+/*
+ * dev_pm_qos_constraints_allocate
+ * @dev: device to allocate data for
+ *
+ * Called at the first call to add_request, for constraint data allocation
+ * Must be called with the dev_pm_qos_mtx mutex held
+ */
+static int dev_pm_qos_constraints_allocate(struct device *dev)
+{
+ struct pm_qos_constraints *c;
+ struct blocking_notifier_head *n;
+
+ c = kzalloc(sizeof(*c), GFP_KERNEL);
+ if (!c)
+ return -ENOMEM;
+
+ n = kzalloc(sizeof(*n), GFP_KERNEL);
+ if (!n) {
+ kfree(c);
+ return -ENOMEM;
+ }
+ BLOCKING_INIT_NOTIFIER_HEAD(n);
+
+ plist_head_init(&c->list);
+ c->target_value = PM_QOS_DEV_LAT_DEFAULT_VALUE;
+ c->default_value = PM_QOS_DEV_LAT_DEFAULT_VALUE;
+ c->type = PM_QOS_MIN;
+ c->notifiers = n;
+
+ spin_lock_irq(&dev->power.lock);
+ dev->power.constraints = c;
+ spin_unlock_irq(&dev->power.lock);
+
+ return 0;
+}
+
+/**
+ * dev_pm_qos_constraints_init - Initalize device's PM QoS constraints pointer.
+ * @dev: target device
+ *
+ * Called from the device PM subsystem during device insertion under
+ * device_pm_lock().
+ */
+void dev_pm_qos_constraints_init(struct device *dev)
+{
+ mutex_lock(&dev_pm_qos_mtx);
+ dev->power.constraints = NULL;
+ dev->power.power_state = PMSG_ON;
+ mutex_unlock(&dev_pm_qos_mtx);
+}
+
+/**
+ * dev_pm_qos_constraints_destroy
+ * @dev: target device
+ *
+ * Called from the device PM subsystem on device removal under device_pm_lock().
+ */
+void dev_pm_qos_constraints_destroy(struct device *dev)
+{
+ struct dev_pm_qos_request *req, *tmp;
+ struct pm_qos_constraints *c;
+
+ mutex_lock(&dev_pm_qos_mtx);
+
+ dev->power.power_state = PMSG_INVALID;
+ c = dev->power.constraints;
+ if (!c)
+ goto out;
+
+ /* Flush the constraints list for the device */
+ plist_for_each_entry_safe(req, tmp, &c->list, node) {
+ /*
+ * Update constraints list and call the notification
+ * callbacks if needed
+ */
+ apply_constraint(req, PM_QOS_REMOVE_REQ, PM_QOS_DEFAULT_VALUE);
+ memset(req, 0, sizeof(*req));
+ }
+
+ spin_lock_irq(&dev->power.lock);
+ dev->power.constraints = NULL;
+ spin_unlock_irq(&dev->power.lock);
+
+ kfree(c->notifiers);
+ kfree(c);
+
+ out:
+ mutex_unlock(&dev_pm_qos_mtx);
+}
+
+/**
+ * dev_pm_qos_add_request - inserts new qos request into the list
+ * @dev: target device for the constraint
+ * @req: pointer to a preallocated handle
+ * @value: defines the qos request
+ *
+ * This function inserts a new entry in the device constraints list of
+ * requested qos performance characteristics. It recomputes the aggregate
+ * QoS expectations of parameters and initializes the dev_pm_qos_request
+ * handle. Caller needs to save this handle for later use in updates and
+ * removal.
+ *
+ * Returns 1 if the aggregated constraint value has changed,
+ * 0 if the aggregated constraint value has not changed,
+ * -EINVAL in case of wrong parameters, -ENOMEM if there's not enough memory
+ * to allocate for data structures, -ENODEV if the device has just been removed
+ * from the system.
+ */
+int dev_pm_qos_add_request(struct device *dev, struct dev_pm_qos_request *req,
+ s32 value)
+{
+ int ret = 0;
+
+ if (!dev || !req) /*guard against callers passing in null */
+ return -EINVAL;
+
+ if (dev_pm_qos_request_active(req)) {
+ WARN(1, KERN_ERR "dev_pm_qos_add_request() called for already "
+ "added request\n");
+ return -EINVAL;
+ }
+
+ req->dev = dev;
+
+ mutex_lock(&dev_pm_qos_mtx);
+
+ if (!dev->power.constraints) {
+ if (dev->power.power_state.event == PM_EVENT_INVALID) {
+ /* The device has been removed from the system. */
+ req->dev = NULL;
+ ret = -ENODEV;
+ goto out;
+ } else {
+ /*
+ * Allocate the constraints data on the first call to
+ * add_request, i.e. only if the data is not already
+ * allocated and if the device has not been removed.
+ */
+ ret = dev_pm_qos_constraints_allocate(dev);
+ }
+ }
+
+ if (!ret)
+ ret = apply_constraint(req, PM_QOS_ADD_REQ, value);
+
+ out:
+ mutex_unlock(&dev_pm_qos_mtx);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(dev_pm_qos_add_request);
+
+/**
+ * dev_pm_qos_update_request - modifies an existing qos request
+ * @req : handle to list element holding a dev_pm_qos request to use
+ * @new_value: defines the qos request
+ *
+ * Updates an existing dev PM qos request along with updating the
+ * target value.
+ *
+ * Attempts are made to make this code callable on hot code paths.
+ *
+ * Returns 1 if the aggregated constraint value has changed,
+ * 0 if the aggregated constraint value has not changed,
+ * -EINVAL in case of wrong parameters, -ENODEV if the device has been
+ * removed from the system
+ */
+int dev_pm_qos_update_request(struct dev_pm_qos_request *req,
+ s32 new_value)
+{
+ int ret = 0;
+
+ if (!req) /*guard against callers passing in null */
+ return -EINVAL;
+
+ if (!dev_pm_qos_request_active(req)) {
+ WARN(1, KERN_ERR "dev_pm_qos_update_request() called for "
+ "unknown object\n");
+ return -EINVAL;
+ }
+
+ mutex_lock(&dev_pm_qos_mtx);
+
+ if (req->dev->power.constraints) {
+ if (new_value != req->node.prio)
+ ret = apply_constraint(req, PM_QOS_UPDATE_REQ,
+ new_value);
+ } else {
+ /* Return if the device has been removed */
+ ret = -ENODEV;
+ }
+
+ mutex_unlock(&dev_pm_qos_mtx);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(dev_pm_qos_update_request);
+
+/**
+ * dev_pm_qos_remove_request - modifies an existing qos request
+ * @req: handle to request list element
+ *
+ * Will remove pm qos request from the list of constraints and
+ * recompute the current target value. Call this on slow code paths.
+ *
+ * Returns 1 if the aggregated constraint value has changed,
+ * 0 if the aggregated constraint value has not changed,
+ * -EINVAL in case of wrong parameters, -ENODEV if the device has been
+ * removed from the system
+ */
+int dev_pm_qos_remove_request(struct dev_pm_qos_request *req)
+{
+ int ret = 0;
+
+ if (!req) /*guard against callers passing in null */
+ return -EINVAL;
+
+ if (!dev_pm_qos_request_active(req)) {
+ WARN(1, KERN_ERR "dev_pm_qos_remove_request() called for "
+ "unknown object\n");
+ return -EINVAL;
+ }
+
+ mutex_lock(&dev_pm_qos_mtx);
+
+ if (req->dev->power.constraints) {
+ ret = apply_constraint(req, PM_QOS_REMOVE_REQ,
+ PM_QOS_DEFAULT_VALUE);
+ memset(req, 0, sizeof(*req));
+ } else {
+ /* Return if the device has been removed */
+ ret = -ENODEV;
+ }
+
+ mutex_unlock(&dev_pm_qos_mtx);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(dev_pm_qos_remove_request);
+
+/**
+ * dev_pm_qos_add_notifier - sets notification entry for changes to target value
+ * of per-device PM QoS constraints
+ *
+ * @dev: target device for the constraint
+ * @notifier: notifier block managed by caller.
+ *
+ * Will register the notifier into a notification chain that gets called
+ * upon changes to the target value for the device.
+ */
+int dev_pm_qos_add_notifier(struct device *dev, struct notifier_block *notifier)
+{
+ int retval = 0;
+
+ mutex_lock(&dev_pm_qos_mtx);
+
+ /* Silently return if the constraints object is not present. */
+ if (dev->power.constraints)
+ retval = blocking_notifier_chain_register(
+ dev->power.constraints->notifiers,
+ notifier);
+
+ mutex_unlock(&dev_pm_qos_mtx);
+ return retval;
+}
+EXPORT_SYMBOL_GPL(dev_pm_qos_add_notifier);
+
+/**
+ * dev_pm_qos_remove_notifier - deletes notification for changes to target value
+ * of per-device PM QoS constraints
+ *
+ * @dev: target device for the constraint
+ * @notifier: notifier block to be removed.
+ *
+ * Will remove the notifier from the notification chain that gets called
+ * upon changes to the target value.
+ */
+int dev_pm_qos_remove_notifier(struct device *dev,
+ struct notifier_block *notifier)
+{
+ int retval = 0;
+
+ mutex_lock(&dev_pm_qos_mtx);
+
+ /* Silently return if the constraints object is not present. */
+ if (dev->power.constraints)
+ retval = blocking_notifier_chain_unregister(
+ dev->power.constraints->notifiers,
+ notifier);
+
+ mutex_unlock(&dev_pm_qos_mtx);
+ return retval;
+}
+EXPORT_SYMBOL_GPL(dev_pm_qos_remove_notifier);
+
+/**
+ * dev_pm_qos_add_global_notifier - sets notification entry for changes to
+ * target value of the PM QoS constraints for any device
+ *
+ * @notifier: notifier block managed by caller.
+ *
+ * Will register the notifier into a notification chain that gets called
+ * upon changes to the target value for any device.
+ */
+int dev_pm_qos_add_global_notifier(struct notifier_block *notifier)
+{
+ return blocking_notifier_chain_register(&dev_pm_notifiers, notifier);
+}
+EXPORT_SYMBOL_GPL(dev_pm_qos_add_global_notifier);
+
+/**
+ * dev_pm_qos_remove_global_notifier - deletes notification for changes to
+ * target value of PM QoS constraints for any device
+ *
+ * @notifier: notifier block to be removed.
+ *
+ * Will remove the notifier from the notification chain that gets called
+ * upon changes to the target value for any device.
+ */
+int dev_pm_qos_remove_global_notifier(struct notifier_block *notifier)
+{
+ return blocking_notifier_chain_unregister(&dev_pm_notifiers, notifier);
+}
+EXPORT_SYMBOL_GPL(dev_pm_qos_remove_global_notifier);