From 2ee5f8f05949735fa2f4c463a5e13fcb3660c719 Mon Sep 17 00:00:00 2001 From: Daniel Lezcano Date: Tue, 8 Dec 2020 17:41:42 +0100 Subject: units: Add Watt units As there are the temperature units, let's add the Watt macros definition. Signed-off-by: Daniel Lezcano Reviewed-by: Lukasz Luba Signed-off-by: Rafael J. Wysocki --- include/linux/units.h | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'include/linux') diff --git a/include/linux/units.h b/include/linux/units.h index aaf716364ec3..92c234e71cab 100644 --- a/include/linux/units.h +++ b/include/linux/units.h @@ -4,6 +4,10 @@ #include +#define MILLIWATT_PER_WATT 1000L +#define MICROWATT_PER_MILLIWATT 1000L +#define MICROWATT_PER_WATT 1000000L + #define ABSOLUTE_ZERO_MILLICELSIUS -273150 static inline long milli_kelvin_to_millicelsius(long t) -- cgit v1.2.3 From a20d0ef97abf486a917aff066c457bdb930425af Mon Sep 17 00:00:00 2001 From: Daniel Lezcano Date: Tue, 8 Dec 2020 17:41:44 +0100 Subject: powercap/drivers/dtpm: Add API for dynamic thermal power management On the embedded world, the complexity of the SoC leads to an increasing number of hotspots which need to be monitored and mitigated as a whole in order to prevent the temperature to go above the normative and legally stated 'skin temperature'. Another aspect is to sustain the performance for a given power budget, for example virtual reality where the user can feel dizziness if the GPU performance is capped while a big CPU is processing something else. Or reduce the battery charging because the dissipated power is too high compared with the power consumed by other devices. The userspace is the most adequate place to dynamically act on the different devices by limiting their power given an application profile: it has the knowledge of the platform. These userspace daemons are in charge of the Dynamic Thermal Power Management (DTPM). Nowadays, the dtpm daemons are abusing the thermal framework as they act on the cooling device state to force a specific and arbitrary state without taking care of the governor decisions. Given the closed loop of some governors that can confuse the logic or directly enter in a decision conflict. As the number of cooling device support is limited today to the CPU and the GPU, the dtpm daemons have little control on the power dissipation of the system. The out of tree solutions are hacking around here and there in the drivers, in the frameworks to have control on the devices. The common solution is to declare them as cooling devices. There is no unification of the power limitation unit, opaque states are used. This patch provides a way to create a hierarchy of constraints using the powercap framework. The devices which are registered as power limit-able devices are represented in this hierarchy as a tree. They are linked together with intermediate nodes which are just there to propagate the constraint to the children. The leaves of the tree are the real devices, the intermediate nodes are virtual, aggregating the children constraints and power characteristics. Each node have a weight on a 2^10 basis, in order to reflect the percentage of power distribution of the children's node. This percentage is used to dispatch the power limit to the children. The weight is computed against the max power of the siblings. This simple approach allows to do a fair distribution of the power limit. Signed-off-by: Daniel Lezcano Reviewed-by: Lukasz Luba Tested-by: Lukasz Luba Signed-off-by: Rafael J. Wysocki --- include/linux/dtpm.h | 75 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 75 insertions(+) create mode 100644 include/linux/dtpm.h (limited to 'include/linux') diff --git a/include/linux/dtpm.h b/include/linux/dtpm.h new file mode 100644 index 000000000000..7a1d0b50e334 --- /dev/null +++ b/include/linux/dtpm.h @@ -0,0 +1,75 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Copyright (C) 2020 Linaro Ltd + * + * Author: Daniel Lezcano + */ +#ifndef ___DTPM_H__ +#define ___DTPM_H__ + +#include + +#define MAX_DTPM_DESCR 8 +#define MAX_DTPM_CONSTRAINTS 1 + +struct dtpm { + struct powercap_zone zone; + struct dtpm *parent; + struct list_head sibling; + struct list_head children; + struct dtpm_ops *ops; + unsigned long flags; + u64 power_limit; + u64 power_max; + u64 power_min; + int weight; + void *private; +}; + +struct dtpm_ops { + u64 (*set_power_uw)(struct dtpm *, u64); + u64 (*get_power_uw)(struct dtpm *); + void (*release)(struct dtpm *); +}; + +struct dtpm_descr; + +typedef int (*dtpm_init_t)(struct dtpm_descr *); + +struct dtpm_descr { + struct dtpm *parent; + const char *name; + dtpm_init_t init; +}; + +/* Init section thermal table */ +extern struct dtpm_descr *__dtpm_table[]; +extern struct dtpm_descr *__dtpm_table_end[]; + +#define DTPM_TABLE_ENTRY(name) \ + static typeof(name) *__dtpm_table_entry_##name \ + __used __section("__dtpm_table") = &name + +#define DTPM_DECLARE(name) DTPM_TABLE_ENTRY(name) + +#define for_each_dtpm_table(__dtpm) \ + for (__dtpm = __dtpm_table; \ + __dtpm < __dtpm_table_end; \ + __dtpm++) + +static inline struct dtpm *to_dtpm(struct powercap_zone *zone) +{ + return container_of(zone, struct dtpm, zone); +} + +int dtpm_update_power(struct dtpm *dtpm, u64 power_min, u64 power_max); + +int dtpm_release_zone(struct powercap_zone *pcz); + +struct dtpm *dtpm_alloc(struct dtpm_ops *ops); + +void dtpm_unregister(struct dtpm *dtpm); + +int dtpm_register(const char *name, struct dtpm *dtpm, struct dtpm *parent); + +#endif -- cgit v1.2.3 From 0e8f68d7f04856a9e2ad4817b477fa35124888bd Mon Sep 17 00:00:00 2001 From: Daniel Lezcano Date: Tue, 8 Dec 2020 17:41:45 +0100 Subject: powercap/drivers/dtpm: Add CPU energy model based support With the powercap dtpm controller, we are able to plug devices with power limitation features in the tree. The following patch introduces the CPU power limitation based on the energy model and the performance states. The power limitation is done at the performance domain level. If some CPUs are unplugged, the corresponding power will be subtracted from the performance domain total power. It is up to the platform to initialize the dtpm tree and add the CPU. Here is an example to create a simple tree with one root node called "pkg" and the CPU's performance domains. static int dtpm_register_pkg(struct dtpm_descr *descr) { struct dtpm *pkg; int ret; pkg = dtpm_alloc(NULL); if (!pkg) return -ENOMEM; ret = dtpm_register(descr->name, pkg, descr->parent); if (ret) return ret; return dtpm_register_cpu(pkg); } static struct dtpm_descr descr = { .name = "pkg", .init = dtpm_register_pkg, }; DTPM_DECLARE(descr); Signed-off-by: Daniel Lezcano Reviewed-by: Lukasz Luba Tested-by: Lukasz Luba Signed-off-by: Rafael J. Wysocki --- include/linux/cpuhotplug.h | 1 + include/linux/dtpm.h | 2 ++ 2 files changed, 3 insertions(+) (limited to 'include/linux') diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h index 0042ef362511..ee09a39627d6 100644 --- a/include/linux/cpuhotplug.h +++ b/include/linux/cpuhotplug.h @@ -193,6 +193,7 @@ enum cpuhp_state { CPUHP_AP_ONLINE_DYN_END = CPUHP_AP_ONLINE_DYN + 30, CPUHP_AP_X86_HPET_ONLINE, CPUHP_AP_X86_KVM_CLK_ONLINE, + CPUHP_AP_DTPM_CPU_ONLINE, CPUHP_AP_ACTIVE, CPUHP_ONLINE, }; diff --git a/include/linux/dtpm.h b/include/linux/dtpm.h index 7a1d0b50e334..e80a332e3d8a 100644 --- a/include/linux/dtpm.h +++ b/include/linux/dtpm.h @@ -72,4 +72,6 @@ void dtpm_unregister(struct dtpm *dtpm); int dtpm_register(const char *name, struct dtpm *dtpm, struct dtpm *parent); +int dtpm_register_cpu(struct dtpm *parent); + #endif -- cgit v1.2.3