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? > 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. thanks, rui
