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Message-ID: <CADGdYn5Enfd1Et3gwVqWjMfMHuyk1LJ9WCScOGpPF0ZLEyk0Fg@mail.gmail.com>
Date: Thu, 12 Jul 2012 08:50:49 +0530
From: amit kachhap <amit.kachhap@...aro.org>
To: Hongbo Zhang <hongbo.zhang@...aro.org>
Cc: linux-samsung-soc@...r.kernel.org, durgadoss.r@...el.com,
patches@...aro.org, linux-kernel@...r.kernel.org,
lm-sensors@...sensors.org, linux-acpi@...r.kernel.org,
rui.zhang@...el.com, khali@...ux-fr.org,
linaro-dev@...ts.linaro.org, linux-pm@...ts.linux-foundation.org,
lenb@...nel.org, akpm@...ux-foundation.org,
guenter.roeck@...csson.com
Subject: Re: [PATCH v4 1/5] thermal: Add generic cpufreq cooling implementation
On Tue, Jul 10, 2012 at 12:31 PM, Hongbo Zhang <hongbo.zhang@...aro.org> wrote:
>
>
> On 12 May 2012 17:40, Amit Daniel Kachhap <amit.kachhap@...aro.org> wrote:
>>
>> This patch adds 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.
>>
>> Signed-off-by: Amit Daniel Kachhap <amit.kachhap@...aro.org>
>> ---
>> Documentation/thermal/cpu-cooling-api.txt | 60 ++++
>> drivers/thermal/Kconfig | 11 +
>> drivers/thermal/Makefile | 3 +-
>> drivers/thermal/cpu_cooling.c | 483
>> +++++++++++++++++++++++++++++
>> include/linux/cpu_cooling.h | 99 ++++++
>> 5 files changed, 655 insertions(+), 1 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..557adb8
>> --- /dev/null
>> +++ b/Documentation/thermal/cpu-cooling-api.txt
>> @@ -0,0 +1,60 @@
>> +CPU cooling APIs How To
>> +===================================
>> +
>> +Written by Amit Daniel Kachhap <amit.kachhap@...aro.org>
>> +
>> +Updated: 12 May 2012
>> +
>> +Copyright (c) 2012 Samsung Electronics Co., Ltd(http://www.samsung.com)
>> +
>> +0. Introduction
>> +
>> +The generic cpu cooling(freq clipping, cpuhotplug etc) 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 freq_clip_table *tab_ptr, unsigned int tab_size)
>> +
>> + This interface function registers the cpufreq cooling device with the
>> name
>> + "thermal-cpufreq-%x". This api can support multiple instances of
>> cpufreq
>> + cooling devices.
>> +
>> + tab_ptr: The table containing the maximum value of frequency to be
>> clipped
>> + for each cooling state.
>> + .freq_clip_max: Value of frequency to be clipped for each allowed
>> + cpus.
>> + .temp_level: Temperature level at which the frequency clamping
>> will
>> + happen.
>> + .mask_val: cpumask of the allowed cpu's
>> + tab_size: the total number of cpufreq cooling states.
>> +
>> +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
>> diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig
>> index 514a691..d9c529f 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 or M here.
>> +
>> config SPEAR_THERMAL
>> bool "SPEAr thermal sensor driver"
>> depends on THERMAL
>> diff --git a/drivers/thermal/Makefile b/drivers/thermal/Makefile
>> index a9fff0b..30c456c 100644
>> --- a/drivers/thermal/Makefile
>> +++ b/drivers/thermal/Makefile
>> @@ -3,4 +3,5 @@
>> #
>>
>> obj-$(CONFIG_THERMAL) += thermal_sys.o
>> -obj-$(CONFIG_SPEAR_THERMAL) += spear_thermal.o
>> \ No newline at end of file
>> +obj-$(CONFIG_CPU_THERMAL) += cpu_cooling.o
>> +obj-$(CONFIG_SPEAR_THERMAL) += spear_thermal.o
>> diff --git a/drivers/thermal/cpu_cooling.c b/drivers/thermal/cpu_cooling.c
>> new file mode 100644
>> index 0000000..c40d9a0
>> --- /dev/null
>> +++ b/drivers/thermal/cpu_cooling.c
>> @@ -0,0 +1,483 @@
>> +/*
>> + * linux/drivers/thermal/cpu_cooling.c
>> + *
>> + * Copyright (C) 2012 Samsung Electronics Co.,
>> Ltd(http://www.samsung.com)
>> + * Copyright (C) 2012 Amit Daniel <amit.kachhap@...aro.org>
>> + *
>> + *
>> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>> + * 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.
>> + * @tab_ptr: freq_clip_table table containing the maximum value of
>> frequency to
>> + * be set for different cooling state.
>> + * @tab_size: integer value representing a count of the above table.
>> + * @cpufreq_state: integer value representing the current state of
>> cpufreq
>> + * cooling devices.
>> + * @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;
>> + struct freq_clip_table *tab_ptr;
>> + unsigned int tab_size;
>> + unsigned int cpufreq_state;
>> + struct cpumask allowed_cpus;
>> + struct list_head node;
>> +};
>> +static LIST_HEAD(cooling_cpufreq_list);
>> +static DEFINE_MUTEX(cooling_cpufreq_lock);
>> +static DEFINE_IDR(cpufreq_idr);
>> +
>> +/*per cpu variable to store the previous max frequency allowed*/
>> +static DEFINE_PER_CPU(unsigned int, max_policy_freq);
>> +
>> +/*notify_table passes value to the CPUFREQ_ADJUST callback function.*/
>> +#define NOTIFY_INVALID NULL
>> +static struct freq_clip_table *notify_table;
>> +
>> +/*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 codes 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);
>> +}
>> +
>> +/**
>> + * 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, state;
>> + struct freq_clip_table *th_table, *table_ptr;
>> + const struct cpumask *maskPtr = &cpufreq_device->allowed_cpus;
>> + struct cpufreq_cooling_device *cpufreq_ptr;
>> +
>> + if (cooling_state > cpufreq_device->tab_size)
>> + return -EINVAL;
>> +
>> + /*Check if the old cooling action is same as new cooling action*/
>> + if (cpufreq_device->cpufreq_state == cooling_state)
>> + return 0;
>> +
>> + /*pass cooling table info to the cpufreq_thermal_notifier
>> callback*/
>> + notify_table = NOTIFY_INVALID;
>> +
>> + if (cooling_state > 0) {
>> + th_table = &(cpufreq_device->tab_ptr[cooling_state - 1]);
>> + notify_table = th_table;
>> + }
>> +
>> + /*check if any lower clip frequency active in other
>> cpufreq_device's*/
>> + list_for_each_entry(cpufreq_ptr, &cooling_cpufreq_list, node) {
>> +
>> + state = cpufreq_ptr->cpufreq_state;
>> + if (state == 0 || cpufreq_ptr == cpufreq_device)
>> + continue;
>> +
>> + if (!cpumask_equal(&cpufreq_ptr->allowed_cpus,
>> + &cpufreq_device->allowed_cpus))
>> + continue;
>> +
>> + table_ptr = &(cpufreq_ptr->tab_ptr[state - 1]);
>> + if (notify_table == NULL ||
>> + (table_ptr->freq_clip_max <
>> + notify_table->freq_clip_max))
>> + notify_table = table_ptr;
>> + }
>> +
>> + cpufreq_device->cpufreq_state = cooling_state;
>> +
>> + if (notify_table != NOTIFY_INVALID) {
>> + event = CPUFREQ_COOLING_START;
>> + maskPtr = notify_table->mask_val;
>> + } else {
>> + event = CPUFREQ_COOLING_STOP;
>> + }
>> +
>> + blocking_notifier_call_chain(&cputherm_state_notifier_list,
>> + event, notify_table);
>> +
>> + for_each_cpu(cpuid, maskPtr) {
>> + if (is_cpufreq_valid(cpuid))
>> + cpufreq_update_policy(cpuid);
>> + }
>> +
>> + notify_table = 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)
>> + return 0;
>> +
>> + if (notify_table != NOTIFY_INVALID) {
>> + max_freq = notify_table->freq_clip_max;
>> +
>> + if (!per_cpu(max_policy_freq, policy->cpu))
>> + per_cpu(max_policy_freq, policy->cpu) =
>> policy->max;
>> + } else {
>> + if (per_cpu(max_policy_freq, policy->cpu)) {
>> + max_freq = per_cpu(max_policy_freq, policy->cpu);
>> + per_cpu(max_policy_freq, policy->cpu) = 0;
>> + } else {
>> + max_freq = policy->max;
>> + }
>> + }
>> +
>> + /* 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;
>> + 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->tab_size;
>> + ret = 0;
>> + break;
>> + }
>> + }
>> + 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);
>> + return ret;
>> +}
>> +
>> +/**
>> + * cpufreq_set_cur_state - callback function to set the current cooling
>> state.
>> + * @cdev: thermal cooling device pointer.
>> + * @state: set this variable to the current cooling state.
>> + */
>> +static int cpufreq_set_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) {
>> + ret = 0;
>> + break;
>> + }
>> + }
>> + if (!ret)
>> + ret = cpufreq_apply_cooling(cpufreq_device, state);
>> +
>> + mutex_unlock(&cooling_cpufreq_lock);
>> +
>> + return ret;
>> +}
>> +
>> +/*Bind cpufreq callbacks to thermal cooling device ops*/
>> +static struct thermal_cooling_device_ops const cpufreq_cooling_ops = {
>> + .get_max_state = cpufreq_get_max_state,
>> + .get_cur_state = cpufreq_get_cur_state,
>> + .set_cur_state = cpufreq_set_cur_state,
>> +};
>> +
>> +/*Notifier for cpufreq policy change*/
>> +static struct notifier_block thermal_cpufreq_notifier_block = {
>> + .notifier_call = cpufreq_thermal_notifier,
>> +};
>> +
>> +/**
>> + * cpufreq_cooling_register - function to create cpufreq cooling device.
>> + * @tab_ptr: table ptr containing the maximum value of frequency to be
>> clipped
>> + * for each cooling state.
>> + * @tab_size: count of entries in the above table.
>> + * happen.
>> + */
>> +struct thermal_cooling_device *cpufreq_cooling_register(
>> + struct freq_clip_table *tab_ptr, unsigned int tab_size)
>> +{
>> + struct thermal_cooling_device *cool_dev;
>> + struct cpufreq_cooling_device *cpufreq_dev = NULL;
>> + struct freq_clip_table *clip_tab;
>> + unsigned int cpufreq_dev_count = 0;
>> + char dev_name[THERMAL_NAME_LENGTH];
>> + int ret = 0, id = 0, i;
>> +
>> + if (tab_ptr == NULL || tab_size == 0)
>> + return ERR_PTR(-EINVAL);
>> +
>> + list_for_each_entry(cpufreq_dev, &cooling_cpufreq_list, node)
>> + cpufreq_dev_count++;
>> +
>> + cpufreq_dev = kzalloc(sizeof(struct cpufreq_cooling_device),
>> + GFP_KERNEL);
>> + if (!cpufreq_dev)
>> + return ERR_PTR(-ENOMEM);
>> +
>> + /*Verify that all the entries of freq_clip_table are present*/
>> + for (i = 0; i < tab_size; i++) {
>> + clip_tab = ((struct freq_clip_table *)&tab_ptr[i]);
>> + if (!clip_tab->freq_clip_max || !clip_tab->mask_val
>> + || !clip_tab->temp_level) {
>
> About clip_tab->temp_level:
> I'd like to remove this variable checking, because as suggested by Vincent
> Guittot, it is better to separate cooling devices
> and thermal zone, thus we can add/remove cooling devices freely/dynamically.
> In such case, a cooling device doesn't
> know any temp_level before binding--the binding condition is name matching,
> what's more, the cooling device should not
> know much data of other devices.
Hi Hongbo,
The temp_level is not used anywhere inside the cooling devices. They
are just present to pass the trip temperature information to the
registered notifiers.
Thanks,
Amit D
>
>> + kfree(cpufreq_dev);
>> + return ERR_PTR(-EINVAL);
>> + }
>> + /*
>> + *Consolidate all the cpumask for all the individual
>> entries
>> + *of the trip table. This is useful in resetting all the
>> + *clipped frequencies to the normal level for each cpufreq
>> + *cooling device.
>> + */
>> + cpumask_or(&cpufreq_dev->allowed_cpus,
>> + &cpufreq_dev->allowed_cpus, clip_tab->mask_val);
>> + }
>> +
>> + cpufreq_dev->tab_ptr = tab_ptr;
>> + cpufreq_dev->tab_size = tab_size;
>> +
>> + ret = get_idr(&cpufreq_idr, &cpufreq_dev->id);
>> + if (ret) {
>> + kfree(cpufreq_dev);
>> + return ERR_PTR(-EINVAL);
>> + }
>> +
>> + sprintf(dev_name, "thermal-cpufreq-%d", cpufreq_dev->id);
>> +
>> + cool_dev = thermal_cooling_device_register(dev_name, cpufreq_dev,
>> + &cpufreq_cooling_ops);
>> + if (!cool_dev) {
>> + release_idr(&cpufreq_idr, cpufreq_dev->id);
>> + kfree(cpufreq_dev);
>> + return ERR_PTR(-EINVAL);
>> + }
>> + cpufreq_dev->id = id;
>> + cpufreq_dev->cool_dev = cool_dev;
>> + mutex_lock(&cooling_cpufreq_lock);
>> + list_add_tail(&cpufreq_dev->node, &cooling_cpufreq_list);
>> +
>> + /*Register the notifier for first cpufreq cooling device*/
>> + if (cpufreq_dev_count == 0)
>> + cpufreq_register_notifier(&thermal_cpufreq_notifier_block,
>> + CPUFREQ_POLICY_NOTIFIER);
>> +
>> + mutex_unlock(&cooling_cpufreq_lock);
>> + return cool_dev;
>> +}
>> +EXPORT_SYMBOL(cpufreq_cooling_register);
>> +
>> +/**
>> + * cpufreq_cooling_unregister - function to remove cpufreq cooling
>> device.
>> + * @cdev: thermal cooling device pointer.
>> + */
>> +void cpufreq_cooling_unregister(struct thermal_cooling_device *cdev)
>> +{
>> + struct cpufreq_cooling_device *cpufreq_dev = NULL;
>> + unsigned int cpufreq_dev_count = 0;
>> +
>> + mutex_lock(&cooling_cpufreq_lock);
>> + list_for_each_entry(cpufreq_dev, &cooling_cpufreq_list, node) {
>> + if (cpufreq_dev && cpufreq_dev->cool_dev == cdev)
>> + break;
>> + cpufreq_dev_count++;
>> + }
>> +
>> + if (!cpufreq_dev || cpufreq_dev->cool_dev != cdev) {
>> + mutex_unlock(&cooling_cpufreq_lock);
>> + return;
>> + }
>> +
>> + list_del(&cpufreq_dev->node);
>> +
>> + /*Unregister the notifier for the last cpufreq cooling device*/
>> + if (cpufreq_dev_count == 1) {
>> +
>> cpufreq_unregister_notifier(&thermal_cpufreq_notifier_block,
>> + CPUFREQ_POLICY_NOTIFIER);
>> + }
>> + mutex_unlock(&cooling_cpufreq_lock);
>> + thermal_cooling_device_unregister(cpufreq_dev->cool_dev);
>> + release_idr(&cpufreq_idr, cpufreq_dev->id);
>> + kfree(cpufreq_dev);
>> +}
>> +EXPORT_SYMBOL(cpufreq_cooling_unregister);
>> diff --git a/include/linux/cpu_cooling.h b/include/linux/cpu_cooling.h
>> new file mode 100644
>> index 0000000..ed6c096
>> --- /dev/null
>> +++ b/include/linux/cpu_cooling.h
>> @@ -0,0 +1,99 @@
>> +/*
>> + * linux/include/linux/cpu_cooling.h
>> + *
>> + * Copyright (C) 2012 Samsung Electronics Co.,
>> Ltd(http://www.samsung.com)
>> + * Copyright (C) 2012 Amit Daniel <amit.kachhap@...aro.org>
>> + *
>> + *
>> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>> + * 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.
>> + *
>> + *
>> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>> + */
>> +
>> +#ifndef __CPU_COOLING_H__
>> +#define __CPU_COOLING_H__
>> +
>> +#include <linux/thermal.h>
>> +
>> +#define CPUFREQ_COOLING_START 0
>> +#define CPUFREQ_COOLING_STOP 1
>> +
>> +/**
>> + * struct freq_clip_table
>> + * @freq_clip_max: maximum frequency allowed for this cooling state.
>> + * @temp_level: Temperature level at which the temperature clipping will
>> + * happen.
>> + * @mask_val: cpumask of the allowed cpu's where the clipping will take
>> place.
>> + *
>> + * This structure is required to be filled and passed to the
>> + * cpufreq_cooling_unregister function.
>> + */
>> +struct freq_clip_table {
>> + unsigned int freq_clip_max;
>> + unsigned int temp_level;
>> + const struct cpumask *mask_val;
>> +};
>> +
>> +/**
>> + * 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_TYPE and CPUHOTPLUG_COOLING_TYPE.
>> + *
>> + * 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);
>> +
>> +/**
>> + * 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_TYPE.
>> + *
>> + * This exported function un-registers a driver with cpu cooling layer.
>> + */
>> +int cputherm_unregister_notifier(struct notifier_block *nb, unsigned int
>> list);
>> +
>> +#ifdef CONFIG_CPU_FREQ
>> +/**
>> + * cpufreq_cooling_register - function to create cpufreq cooling device.
>> + * @tab_ptr: table ptr containing the maximum value of frequency to be
>> clipped
>> + * for each cooling state.
>> + * @tab_size: count of entries in the above table.
>> + * @mask_val: cpumask containing the allowed cpu's where frequency
>> clipping can
>> + * happen.
>> + */
>> +struct thermal_cooling_device *cpufreq_cooling_register(
>> + struct freq_clip_table *tab_ptr, unsigned int tab_size);
>> +
>> +/**
>> + * cpufreq_cooling_unregister - function to remove cpufreq cooling
>> device.
>> + * @cdev: thermal cooling device pointer.
>> + */
>> +void cpufreq_cooling_unregister(struct thermal_cooling_device *cdev);
>> +#else /*!CONFIG_CPU_FREQ*/
>> +static inline struct thermal_cooling_device *cpufreq_cooling_register(
>> + struct freq_clip_table *tab_ptr, unsigned int tab_size);
>> +{
>> + return NULL;
>> +}
>> +static inline void cpufreq_cooling_unregister(
>> + struct thermal_cooling_device *cdev)
>> +{
>> + return;
>> +}
>> +#endif /*CONFIG_CPU_FREQ*/
>> +
>> +#endif /* __CPU_COOLING_H__ */
>> --
>> 1.7.1
>>
>>
>> _______________________________________________
>>
>> linaro-dev mailing list
>> linaro-dev@...ts.linaro.org
>> http://lists.linaro.org/mailman/listinfo/linaro-dev
>
>
>
> _______________________________________________
> linaro-dev mailing list
> linaro-dev@...ts.linaro.org
> http://lists.linaro.org/mailman/listinfo/linaro-dev
>
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