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Message-ID: <CAMXH7KHMccn71-4-6QSZ8k98QZhF2yNXpDkZ5Cs4nf5Y-wd3gw@mail.gmail.com>
Date: Mon, 25 Jun 2012 22:12:55 -0500
From: Rob Lee <rob.lee@...aro.org>
To: Amit Daniel Kachhap <amit.kachhap@...aro.org>
Cc: 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
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
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.
(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)
> +/**
> + * 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);
> +{
> + 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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