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Date: Tue, 10 Jul 2012 10:16:52 +0530
From: amit kachhap <amit.kachhap@...il.com>
To: "Valentin, Eduardo" <eduardo.valentin@...com>
Cc: Rob Lee <rob.lee@...aro.org>, linux-pm@...ts.linux-foundation.org,
akpm@...ux-foundation.org, 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, khali@...ux-fr.org,
linaro-dev@...ts.linaro.org, rui.zhang@...el.com,
guenter.roeck@...csson.com, lenb@...nel.org
Subject: Re: [PATCH v4 1/5] thermal: Add generic cpufreq cooling implementation
Hi Rob/Eduardo,
As these patches have still not made into mainline. I will rebase the
whole set along with your suggestion and send them shortly.
Sorry for late reply.
Thanks,
Amit Daniel
On Tue, Jun 26, 2012 at 1:12 PM, Valentin, Eduardo
<eduardo.valentin@...com> wrote:
> Hey Rob and Amit,
>
> On Tue, Jun 26, 2012 at 6:12 AM, Rob Lee <rob.lee@...aro.org> wrote:
>> Hey Amit,
>>
>> I was just re-organizing the imx thermal driver that uses this cpu
>> cooling interface and noticed a couple of small issues here. If
>
> While rewriting the OMAP BG driver on top of this series I noticed
> similar issues. Apart from those pointed by Rob, I have another minor
> fix.
>
>> these suggestions are agreed upon and if it's too late for these
>> issues be changed with this patchset, I can submit them separately
>> unless you'd prefer to.
>>
>> On Sat, May 12, 2012 at 4:40 AM, 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
>>
>> Perhaps the name CPU_COOLING or CPUFREQ_COOLING would more accurately
>> describe this functionality? I like the latter since now this
>> mechanism only supports cooling by using cpufreq.
>>
>>> + bool "generic cpu cooling support"
>>
>> If we use CPUFREQ_COOLING, then perhaps this could say:
>>
>> bool "cpu cooling through cpufreq frequency limiting"
>>
>>> + 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.
>>> +
>>
>> Currently, only the "frequency reduction" method exists so perhaps
>> it's best to remove mention of "cpu hotplug and any other ways of
>> reducing temperature"? Here'as a version for cpufreq only:
>>
>> config CPUFREQ_COOLING
>> bool "cpu cooling through cpufreq frequency limiting"
>> depends on THERMAL && CPU_FREQ
>> help
>> This implements a generic cpu cooling mechanism through cpufreq
>> frequency limiting. 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) {
>>> + 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.
>>
>> CPUFREQ_COOLING_TYPE and CPUHOTPLUG_COOLING_TYPE should be changed to
>> CPUFREQ_COOLING_START CPUFREQ_COOLING_STOP, right?
>>
>>> + *
>>> + * 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.
>>
>> Should be changed to CPUFREQ_COOLING_START, CPUFREQ_COOLING_STOP, right?
>>
>>> + *
>>> + * 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
>>
>> Consider changing this to "#ifdef CPU_THERMAL" A platform thermal
>> driver may want to always call this function as its cpu cooling
>> mechanism but it should still function without the cpu_cooling being
>> enabled. In this case, the platform thermal driver would only provide
>> temperature readings and critical trip point handling. But if the
>> platform happened may have CONFIG_CPU_FREQ enabled, a build error
>> would occur in the current implementation.
>
> I agree here. It makes more sense to have the check against CPU_THERMAL
>
>>
>> (the CONFIG_CPU_FREQ requirement will be met by CPU_THERMAL being
>> enabled since it also implies CONFIG_CPU_FREQ being enabled per the
>> Kconfig dependency)
>
> True.
>
>>
>>> +/**
>>> + * 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*/
>>
>> Modify comment if above suggestion is taken.
>>
>>> +static inline struct thermal_cooling_device *cpufreq_cooling_register(
>>> + struct freq_clip_table *tab_ptr, unsigned int tab_size);
>
> The above semicollon will cause a build error in case this path of the
> ifdef is taken.
>
>>> +{
>>> + return NULL;
>>> +}
>>> +static inline void cpufreq_cooling_unregister(
>>> + struct thermal_cooling_device *cdev)
>>> +{
>>> + return;
>>> +}
>>> +#endif /*CONFIG_CPU_FREQ*/
>>
>> Modify comment if above suggestion is taken.
>>
>>> +
>>> +#endif /* __CPU_COOLING_H__ */
>>> --
>>> 1.7.1
>>>
>>>
>>> _______________________________________________
>>> linaro-dev mailing list
>>> linaro-dev@...ts.linaro.org
>>> http://lists.linaro.org/mailman/listinfo/linaro-dev
>> --
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>
>
>
> --
>
> Eduardo Valentin
> --
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> the body of a message to majordomo@...r.kernel.org
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