On 17 August 2012 12:54, Zhang Rui <rui.zhang@xxxxxxxxx> wrote: > On 四, 2012-08-16 at 17:11 +0530, Amit Daniel Kachhap wrote: >> This patchset introduces a new generic cooling device based on cpufreq >> that can be used on non-ACPI platforms. As a proof of concept, we have >> drivers for the following platforms using this mechanism now: >> >> * Samsung Exynos (Exynos4 and Exynos5) in the current patchset. >> * Freescale i.MX (git://git.linaro.org/people/amitdanielk/linux.git imx6q_thermal) >> >> There is a small change in cpufreq cooling registration APIs, so a minor >> change is needed for Freescale platforms. >> >> Brief Description: >> >> 1) The generic cooling devices code is placed inside driver/thermal/* >> as placing inside acpi folder will need un-necessary enabling of acpi >> code. This code is architecture independent. >> >> 2) This patchset adds generic cpu cooling low level implementation >> through frequency clipping. In future, other cpu related cooling >> devices may be added here. An ACPI version of this already exists >> (drivers/acpi/processor_thermal.c) .But this will be useful for >> platforms like ARM using the generic thermal interface along with the >> generic cpu cooling devices. The cooling device registration API's >> return cooling device pointers which can be easily binded with the >> thermal zone trip points. The important APIs exposed are, >> >> a) struct thermal_cooling_device *cpufreq_cooling_register( >> struct cpumask *clip_cpus) >> b) void cpufreq_cooling_unregister(struct thermal_cooling_device *cdev) >> >> 3) Samsung exynos platform thermal implementation is done using the >> generic cpu cooling APIs and the new trip type. The temperature sensor >> driver present in the hwmon folder(registered as hwmon driver) is moved >> to thermal folder and registered as a thermal driver. >> >> A simple data/control flow diagrams is shown below, >> >> Core Linux thermal <-----> Exynos thermal interface <----- Temperature Sensor >> | | >> \|/ | >> Cpufreq cooling device <--------------- >> >> TODO: >> *Will send the DT enablement patches later after the driver is merged. >> >> This patch: >> >> Add support for generic cpu thermal cooling low level implementations >> using frequency scaling up/down based on the registration parameters. >> Different cpu related cooling devices can be registered by the user and >> the binding of these cooling devices to the corresponding trip points can >> be easily done as the registration APIs return the cooling device pointer. >> The user of these APIs are responsible for passing clipping frequency . >> The drivers can also register to recieve notification about any cooling >> action called. >> >> [akpm@xxxxxxxxxxxxxxxxxxxx: fix comment layout] >> Signed-off-by: Amit Daniel Kachhap <amit.kachhap@xxxxxxxxxx> >> Cc: Guenter Roeck <guenter.roeck@xxxxxxxxxxxx> >> Cc: SangWook Ju <sw.ju@xxxxxxxxxxx> >> Cc: Durgadoss <durgadoss.r@xxxxxxxxx> >> Cc: Len Brown <lenb@xxxxxxxxxx> >> Cc: Jean Delvare <khali@xxxxxxxxxxxx> >> Cc: Kyungmin Park <kmpark@xxxxxxxxxxxxx> >> Cc: Kukjin Kim <kgene.kim@xxxxxxxxxxx> >> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> >> Signed-off-by: Amit Daniel Kachhap <amit.daniel@xxxxxxxxxxx> >> --- >> Documentation/thermal/cpu-cooling-api.txt | 52 +++ >> drivers/thermal/Kconfig | 11 + >> drivers/thermal/Makefile | 1 + >> drivers/thermal/cpu_cooling.c | 512 +++++++++++++++++++++++++++++ >> include/linux/cpu_cooling.h | 79 +++++ >> 5 files changed, 655 insertions(+), 0 deletions(-) >> create mode 100644 Documentation/thermal/cpu-cooling-api.txt >> create mode 100644 drivers/thermal/cpu_cooling.c >> create mode 100644 include/linux/cpu_cooling.h >> >> diff --git a/Documentation/thermal/cpu-cooling-api.txt b/Documentation/thermal/cpu-cooling-api.txt >> new file mode 100644 >> index 0000000..a1f2a6b >> --- /dev/null >> +++ b/Documentation/thermal/cpu-cooling-api.txt >> @@ -0,0 +1,52 @@ >> +CPU cooling APIs How To >> +=================================== >> + >> +Written by Amit Daniel Kachhap <amit.kachhap@xxxxxxxxxx> >> + >> +Updated: 12 May 2012 >> + >> +Copyright (c) 2012 Samsung Electronics Co., Ltd(http://www.samsung.com) >> + >> +0. Introduction >> + >> +The generic cpu cooling(freq clipping) provides registration/unregistration APIs >> +to the caller. The binding of the cooling devices to the trip point is left for >> +the user. The registration APIs returns the cooling device pointer. >> + >> +1. cpu cooling APIs >> + >> +1.1 cpufreq registration/unregistration APIs >> +1.1.1 struct thermal_cooling_device *cpufreq_cooling_register( >> + struct cpumask *clip_cpus) >> + >> + This interface function registers the cpufreq cooling device with the name >> + "thermal-cpufreq-%x". This api can support multiple instances of cpufreq >> + cooling devices. >> + >> + clip_cpus: cpumask of cpus where the frequency constraints will happen. >> + >> +1.1.2 void cpufreq_cooling_unregister(struct thermal_cooling_device *cdev) >> + >> + This interface function unregisters the "thermal-cpufreq-%x" cooling device. >> + >> + cdev: Cooling device pointer which has to be unregistered. >> + >> + >> +1.2 CPU cooling action notifier register/unregister interface >> +1.2.1 int cputherm_register_notifier(struct notifier_block *nb, >> + unsigned int list) >> + >> + This interface registers a driver with cpu cooling layer. The driver will >> + be notified when any cpu cooling action is called. >> + >> + nb: notifier function to register >> + list: CPUFREQ_COOLING_START or CPUFREQ_COOLING_STOP >> + >> +1.2.2 int cputherm_unregister_notifier(struct notifier_block *nb, >> + unsigned int list) >> + >> + This interface registers a driver with cpu cooling layer. The driver will >> + be notified when any cpu cooling action is called. >> + >> + nb: notifier function to register >> + list: CPUFREQ_COOLING_START or CPUFREQ_COOLING_STOP > > what are these two APIs used for? > I did not see they are used in your patch set, do I miss something? No currently they are not used by my patches. I added them on request from Eduardo and others > >> diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig >> index 7dd8c34..996003b 100644 >> --- a/drivers/thermal/Kconfig >> +++ b/drivers/thermal/Kconfig >> @@ -19,6 +19,17 @@ config THERMAL_HWMON >> depends on HWMON=y || HWMON=THERMAL >> default y >> >> +config CPU_THERMAL >> + bool "generic cpu cooling support" >> + depends on THERMAL && CPU_FREQ >> + help >> + This implements the generic cpu cooling mechanism through frequency >> + reduction, cpu hotplug and any other ways of reducing temperature. An >> + ACPI version of this already exists(drivers/acpi/processor_thermal.c). >> + This will be useful for platforms using the generic thermal interface >> + and not the ACPI interface. >> + If you want this support, you should say Y here. >> + >> config SPEAR_THERMAL >> bool "SPEAr thermal sensor driver" >> depends on THERMAL >> diff --git a/drivers/thermal/Makefile b/drivers/thermal/Makefile >> index fd9369a..aae59ad 100644 >> --- a/drivers/thermal/Makefile >> +++ b/drivers/thermal/Makefile >> @@ -3,5 +3,6 @@ >> # >> >> obj-$(CONFIG_THERMAL) += thermal_sys.o >> +obj-$(CONFIG_CPU_THERMAL) += cpu_cooling.o >> obj-$(CONFIG_SPEAR_THERMAL) += spear_thermal.o >> obj-$(CONFIG_RCAR_THERMAL) += rcar_thermal.o >> diff --git a/drivers/thermal/cpu_cooling.c b/drivers/thermal/cpu_cooling.c >> new file mode 100644 >> index 0000000..c42e557 >> --- /dev/null >> +++ b/drivers/thermal/cpu_cooling.c >> @@ -0,0 +1,512 @@ >> +/* >> + * linux/drivers/thermal/cpu_cooling.c >> + * >> + * Copyright (C) 2012 Samsung Electronics Co., Ltd(http://www.samsung.com) >> + * Copyright (C) 2012 Amit Daniel <amit.kachhap@xxxxxxxxxx> >> + * >> + * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ >> + * This program is free software; you can redistribute it and/or modify >> + * it under the terms of the GNU General Public License as published by >> + * the Free Software Foundation; version 2 of the License. >> + * >> + * This program is distributed in the hope that it will be useful, but >> + * WITHOUT ANY WARRANTY; without even the implied warranty of >> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU >> + * General Public License for more details. >> + * >> + * You should have received a copy of the GNU General Public License along >> + * with this program; if not, write to the Free Software Foundation, Inc., >> + * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. >> + * >> + * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ >> + */ >> +#include <linux/kernel.h> >> +#include <linux/module.h> >> +#include <linux/thermal.h> >> +#include <linux/platform_device.h> >> +#include <linux/cpufreq.h> >> +#include <linux/err.h> >> +#include <linux/slab.h> >> +#include <linux/cpu.h> >> +#include <linux/cpu_cooling.h> >> + >> +/** >> + * struct cpufreq_cooling_device >> + * @id: unique integer value corresponding to each cpufreq_cooling_device >> + * registered. >> + * @cool_dev: thermal_cooling_device pointer to keep track of the the >> + * egistered cooling device. >> + * @cpufreq_state: integer value representing the current state of cpufreq >> + * cooling devices. >> + * @cpufreq_val: integer value representing the absolute value of the clipped >> + * frequency. >> + * @allowed_cpus: all the cpus involved for this cpufreq_cooling_device. >> + * @node: list_head to link all cpufreq_cooling_device together. >> + * >> + * This structure is required for keeping information of each >> + * cpufreq_cooling_device registered as a list whose head is represented by >> + * cooling_cpufreq_list. In order to prevent corruption of this list a >> + * mutex lock cooling_cpufreq_lock is used. >> + */ >> +struct cpufreq_cooling_device { >> + int id; >> + struct thermal_cooling_device *cool_dev; >> + unsigned int cpufreq_state; >> + unsigned int cpufreq_val; >> + struct cpumask allowed_cpus; >> + struct list_head node; >> +}; >> +static LIST_HEAD(cooling_cpufreq_list); >> +static DEFINE_IDR(cpufreq_idr); >> + >> +static struct mutex cooling_cpufreq_lock; >> + >> +/* notify_table passes value to the CPUFREQ_ADJUST callback function. */ >> +#define NOTIFY_INVALID NULL >> +struct cpufreq_cooling_device *notify_device; >> + >> +/* Head of the blocking notifier chain to inform about frequency clamping */ >> +static BLOCKING_NOTIFIER_HEAD(cputherm_state_notifier_list); >> + >> +/** >> + * get_idr - function to get a unique id. >> + * @idr: struct idr * handle used to create a id. >> + * @id: int * value generated by this function. >> + */ >> +static int get_idr(struct idr *idr, int *id) >> +{ >> + int err; >> +again: >> + if (unlikely(idr_pre_get(idr, GFP_KERNEL) == 0)) >> + return -ENOMEM; >> + >> + mutex_lock(&cooling_cpufreq_lock); >> + err = idr_get_new(idr, NULL, id); >> + mutex_unlock(&cooling_cpufreq_lock); >> + >> + if (unlikely(err == -EAGAIN)) >> + goto again; >> + else if (unlikely(err)) >> + return err; >> + >> + *id = *id & MAX_ID_MASK; >> + return 0; >> +} >> + >> +/** >> + * release_idr - function to free the unique id. >> + * @idr: struct idr * handle used for creating the id. >> + * @id: int value representing the unique id. >> + */ >> +static void release_idr(struct idr *idr, int id) >> +{ >> + mutex_lock(&cooling_cpufreq_lock); >> + idr_remove(idr, id); >> + mutex_unlock(&cooling_cpufreq_lock); >> +} >> + >> +/** >> + * cputherm_register_notifier - Register a notifier with cpu cooling interface. >> + * @nb: struct notifier_block * with callback info. >> + * @list: integer value for which notification is needed. possible values are >> + * CPUFREQ_COOLING_START and CPUFREQ_COOLING_STOP. >> + * >> + * This exported function registers a driver with cpu cooling layer. The driver >> + * will be notified when any cpu cooling action is called. >> + */ >> +int cputherm_register_notifier(struct notifier_block *nb, unsigned int list) >> +{ >> + int ret = 0; >> + >> + switch (list) { >> + case CPUFREQ_COOLING_START: >> + case CPUFREQ_COOLING_STOP: >> + ret = blocking_notifier_chain_register( >> + &cputherm_state_notifier_list, nb); >> + break; >> + default: >> + ret = -EINVAL; >> + } >> + return ret; >> +} >> +EXPORT_SYMBOL(cputherm_register_notifier); >> + >> +/** >> + * cputherm_unregister_notifier - Un-register a notifier. >> + * @nb: struct notifier_block * with callback info. >> + * @list: integer value for which notification is needed. values possible are >> + * CPUFREQ_COOLING_START or CPUFREQ_COOLING_STOP. >> + * >> + * This exported function un-registers a driver with cpu cooling layer. >> + */ >> +int cputherm_unregister_notifier(struct notifier_block *nb, unsigned int list) >> +{ >> + int ret = 0; >> + >> + switch (list) { >> + case CPUFREQ_COOLING_START: >> + case CPUFREQ_COOLING_STOP: >> + ret = blocking_notifier_chain_unregister( >> + &cputherm_state_notifier_list, nb); >> + break; >> + default: >> + ret = -EINVAL; >> + } >> + return ret; >> +} >> +EXPORT_SYMBOL(cputherm_unregister_notifier); >> + >> +/* Below code defines functions to be used for cpufreq as cooling device */ >> + >> +/** >> + * is_cpufreq_valid - function to check if a cpu has frequency transition policy. >> + * @cpu: cpu for which check is needed. >> + */ >> +static int is_cpufreq_valid(int cpu) >> +{ >> + struct cpufreq_policy policy; >> + return !cpufreq_get_policy(&policy, cpu); >> +} >> + >> +/** >> + * get_cpu_frequency - get the absolute value of frequency from level. >> + * @cpu: cpu for which frequency is fetched. >> + * @level: level of frequency of the CPU >> + * e.g level=1 --> 1st MAX FREQ, LEVEL=2 ---> 2nd MAX FREQ, .... etc >> + */ >> +static unsigned int get_cpu_frequency(unsigned int cpu, unsigned long level) >> +{ >> + int ret = 0, i = 0; >> + unsigned long level_index; >> + bool descend = false; >> + struct cpufreq_frequency_table *table = >> + cpufreq_frequency_get_table(cpu); >> + if (!table) >> + return ret; >> + >> + while (table[i].frequency != CPUFREQ_TABLE_END) { >> + if (table[i].frequency == CPUFREQ_ENTRY_INVALID) >> + continue; >> + >> + /*check if table in ascending or descending order*/ >> + if ((table[i + 1].frequency != CPUFREQ_TABLE_END) && >> + (table[i + 1].frequency < table[i].frequency) >> + && !descend) { >> + descend = true; >> + } >> + >> + /*return if level matched and table in descending order*/ >> + if (descend && i == level) >> + return table[i].frequency; >> + i++; >> + } >> + i--; >> + >> + if (level > i || descend) >> + return ret; >> + level_index = i - level; >> + >> + /*Scan the table in reverse order and match the level*/ >> + while (i >= 0) { >> + if (table[i].frequency == CPUFREQ_ENTRY_INVALID) >> + continue; >> + /*return if level matched*/ >> + if (i == level_index) >> + return table[i].frequency; >> + i--; >> + } >> + return ret; >> +} >> + >> +/** >> + * cpufreq_apply_cooling - function to apply frequency clipping. >> + * @cpufreq_device: cpufreq_cooling_device pointer containing frequency >> + * clipping data. >> + * @cooling_state: value of the cooling state. >> + */ >> +static int cpufreq_apply_cooling(struct cpufreq_cooling_device *cpufreq_device, >> + unsigned long cooling_state) >> +{ >> + unsigned int event, cpuid, clip_freq; >> + struct cpumask *maskPtr = &cpufreq_device->allowed_cpus; >> + unsigned int cpu = cpumask_any(maskPtr); >> + >> + >> + /* Check if the old cooling action is same as new cooling action */ >> + if (cpufreq_device->cpufreq_state == cooling_state) >> + return 0; >> + >> + clip_freq = get_cpu_frequency(cpu, cooling_state); >> + if (!clip_freq) >> + return -EINVAL; >> + >> + cpufreq_device->cpufreq_state = cooling_state; >> + cpufreq_device->cpufreq_val = clip_freq; >> + notify_device = cpufreq_device; >> + >> + if (cooling_state != 0) >> + event = CPUFREQ_COOLING_START; >> + else >> + event = CPUFREQ_COOLING_STOP; >> + >> + blocking_notifier_call_chain(&cputherm_state_notifier_list, >> + event, &clip_freq); >> + >> + for_each_cpu(cpuid, maskPtr) { >> + if (is_cpufreq_valid(cpuid)) >> + cpufreq_update_policy(cpuid); >> + } >> + >> + notify_device = NOTIFY_INVALID; >> + >> + return 0; >> +} >> + >> +/** >> + * cpufreq_thermal_notifier - notifier callback for cpufreq policy change. >> + * @nb: struct notifier_block * with callback info. >> + * @event: value showing cpufreq event for which this function invoked. >> + * @data: callback-specific data >> + */ >> +static int cpufreq_thermal_notifier(struct notifier_block *nb, >> + unsigned long event, void *data) >> +{ >> + struct cpufreq_policy *policy = data; >> + unsigned long max_freq = 0; >> + >> + if (event != CPUFREQ_ADJUST || notify_device == NOTIFY_INVALID) >> + return 0; >> + >> + if (cpumask_test_cpu(policy->cpu, ¬ify_device->allowed_cpus)) >> + max_freq = notify_device->cpufreq_val; >> + >> + /* Never exceed user_policy.max*/ >> + if (max_freq > policy->user_policy.max) >> + max_freq = policy->user_policy.max; >> + >> + if (policy->max != max_freq) >> + cpufreq_verify_within_limits(policy, 0, max_freq); >> + >> + return 0; >> +} >> + >> +/* >> + * cpufreq cooling device callback functions are defined below >> + */ >> + >> +/** >> + * cpufreq_get_max_state - callback function to get the max cooling state. >> + * @cdev: thermal cooling device pointer. >> + * @state: fill this variable with the max cooling state. >> + */ >> +static int cpufreq_get_max_state(struct thermal_cooling_device *cdev, >> + unsigned long *state) >> +{ >> + int ret = -EINVAL, i = 0; >> + struct cpufreq_cooling_device *cpufreq_device; >> + struct cpumask *maskPtr; >> + unsigned int cpu; >> + struct cpufreq_frequency_table *table; >> + >> + mutex_lock(&cooling_cpufreq_lock); >> + list_for_each_entry(cpufreq_device, &cooling_cpufreq_list, node) { >> + if (cpufreq_device && cpufreq_device->cool_dev == cdev) >> + break; >> + } >> + if (cpufreq_device == NULL) >> + goto return_get_max_state; >> + >> + maskPtr = &cpufreq_device->allowed_cpus; >> + cpu = cpumask_any(maskPtr); >> + table = cpufreq_frequency_get_table(cpu); >> + if (!table) { >> + *state = 0; >> + ret = 0; >> + goto return_get_max_state; >> + } >> + >> + while (table[i].frequency != CPUFREQ_TABLE_END) { >> + if (table[i].frequency == CPUFREQ_ENTRY_INVALID) >> + continue; >> + i++; >> + } >> + if (i > 0) { >> + *state = --i; >> + ret = 0; >> + } >> + >> +return_get_max_state: >> + mutex_unlock(&cooling_cpufreq_lock); >> + return ret; >> +} >> + >> +/** >> + * cpufreq_get_cur_state - callback function to get the current cooling state. >> + * @cdev: thermal cooling device pointer. >> + * @state: fill this variable with the current cooling state. >> + */ >> +static int cpufreq_get_cur_state(struct thermal_cooling_device *cdev, >> + unsigned long *state) >> +{ >> + int ret = -EINVAL; >> + struct cpufreq_cooling_device *cpufreq_device; >> + >> + mutex_lock(&cooling_cpufreq_lock); >> + list_for_each_entry(cpufreq_device, &cooling_cpufreq_list, node) { >> + if (cpufreq_device && cpufreq_device->cool_dev == cdev) { >> + *state = cpufreq_device->cpufreq_state; >> + ret = 0; >> + break; >> + } >> + } >> + mutex_unlock(&cooling_cpufreq_lock); >> + > > as cpufreq may be changed in other places, e.g. via sysfs I/F, we should > use the current cpu frequency to get the REAL cooling state, rather than > using a cached value. Yes agreed , I will repost with your suggestion. Thanks, Amit > > thanks, > rui > >
