[linux-2.6-block.git] / drivers / thermal / cpu_cooling.c

/*
 *  linux/drivers/thermal/cpu_cooling.c
 *
 *  Copyright (C) 2012	Samsung Electronics Co., Ltd(http://www.samsung.com)
 *  Copyright (C) 2012  Amit Daniel <amit.kachhap@linaro.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.
 * @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 DEFINE_MUTEX(cooling_cpufreq_lock);

static unsigned int cpufreq_dev_count;

/* notify_table passes value to the CPUFREQ_ADJUST callback function. */
#define NOTIFY_INVALID NULL
static struct cpufreq_cooling_device *notify_device;

/**
 * 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 ret;

	mutex_lock(&cooling_cpufreq_lock);
	ret = idr_alloc(idr, NULL, 0, 0, GFP_KERNEL);
	mutex_unlock(&cooling_cpufreq_lock);
	if (unlikely(ret < 0))
		return ret;
	*id = ret;
	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);
}

/* 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, equals cooling state of cpu cooling device
 *	e.g level=0 --> 1st MAX FREQ, level=1 ---> 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 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;

	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, &notify_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)
{
	struct cpufreq_cooling_device *cpufreq_device = cdev->devdata;
	struct cpumask *maskPtr = &cpufreq_device->allowed_cpus;
	unsigned int cpu;
	struct cpufreq_frequency_table *table;
	unsigned long count = 0;
	int i = 0;

	cpu = cpumask_any(maskPtr);
	table = cpufreq_frequency_get_table(cpu);
	if (!table) {
		*state = 0;
		return 0;
	}

	for (i = 0; (table[i].frequency != CPUFREQ_TABLE_END); i++) {
		if (table[i].frequency == CPUFREQ_ENTRY_INVALID)
			continue;
		count++;
	}

	if (count > 0) {
		*state = --count;
		return 0;
	}

	return -EINVAL;
}

/**
 * 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)
{
	struct cpufreq_cooling_device *cpufreq_device = cdev->devdata;

	*state = cpufreq_device->cpufreq_state;
	return 0;
}

/**
 * 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)
{
	struct cpufreq_cooling_device *cpufreq_device = cdev->devdata;

	return cpufreq_apply_cooling(cpufreq_device, state);
}

/* 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.
 * @clip_cpus: cpumask of cpus where the frequency constraints will happen.
 */
struct thermal_cooling_device *cpufreq_cooling_register(
	const struct cpumask *clip_cpus)
{
	struct thermal_cooling_device *cool_dev;
	struct cpufreq_cooling_device *cpufreq_dev = NULL;
	unsigned int min = 0, max = 0;
	char dev_name[THERMAL_NAME_LENGTH];
	int ret = 0, i;
	struct cpufreq_policy policy;

	/*Verify that all the clip cpus have same freq_min, freq_max limit*/
	for_each_cpu(i, clip_cpus) {
		/*continue if cpufreq policy not found and not return error*/
		if (!cpufreq_get_policy(&policy, i))
			continue;
		if (min == 0 && max == 0) {
			min = policy.cpuinfo.min_freq;
			max = policy.cpuinfo.max_freq;
		} else {
			if (min != policy.cpuinfo.min_freq ||
				max != policy.cpuinfo.max_freq)
				return ERR_PTR(-EINVAL);
		}
	}
	cpufreq_dev = kzalloc(sizeof(struct cpufreq_cooling_device),
			GFP_KERNEL);
	if (!cpufreq_dev)
		return ERR_PTR(-ENOMEM);

	cpumask_copy(&cpufreq_dev->allowed_cpus, clip_cpus);

	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->cool_dev = cool_dev;
	cpufreq_dev->cpufreq_state = 0;
	mutex_lock(&cooling_cpufreq_lock);

	/* Register the notifier for first cpufreq cooling device */
	if (cpufreq_dev_count == 0)
		cpufreq_register_notifier(&thermal_cpufreq_notifier_block,
						CPUFREQ_POLICY_NOTIFIER);
	cpufreq_dev_count++;

	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 = cdev->devdata;

	mutex_lock(&cooling_cpufreq_lock);
	cpufreq_dev_count--;

	/* Unregister the notifier for the last cpufreq cooling device */
	if (cpufreq_dev_count == 0) {
		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);
Commit	Line	Data
02361418 ADK	1	/*
	2	* linux/drivers/thermal/cpu_cooling.c
	3	*
	4	* Copyright (C) 2012 Samsung Electronics Co., Ltd(http://www.samsung.com)
	5	* Copyright (C) 2012 Amit Daniel <amit.kachhap@linaro.org>
	6	*
	7	* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
	8	* This program is free software; you can redistribute it and/or modify
	9	* it under the terms of the GNU General Public License as published by
	10	* the Free Software Foundation; version 2 of the License.
	11	*
	12	* This program is distributed in the hope that it will be useful, but
	13	* WITHOUT ANY WARRANTY; without even the implied warranty of
	14	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	15	* General Public License for more details.
	16	*
	17	* You should have received a copy of the GNU General Public License along
	18	* with this program; if not, write to the Free Software Foundation, Inc.,
	19	* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
	20	*
	21	* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
	22	*/
	23	#include <linux/kernel.h>
	24	#include <linux/module.h>
	25	#include <linux/thermal.h>
	26	#include <linux/platform_device.h>
	27	#include <linux/cpufreq.h>
	28	#include <linux/err.h>
	29	#include <linux/slab.h>
	30	#include <linux/cpu.h>
	31	#include <linux/cpu_cooling.h>
	32
	33	/**
	34	* struct cpufreq_cooling_device
	35	* @id: unique integer value corresponding to each cpufreq_cooling_device
	36	* registered.
	37	* @cool_dev: thermal_cooling_device pointer to keep track of the the
	38	* egistered cooling device.
	39	* @cpufreq_state: integer value representing the current state of cpufreq
	40	* cooling devices.
	41	* @cpufreq_val: integer value representing the absolute value of the clipped
	42	* frequency.
	43	* @allowed_cpus: all the cpus involved for this cpufreq_cooling_device.
	44	* @node: list_head to link all cpufreq_cooling_device together.
	45	*
	46	* This structure is required for keeping information of each
	47	* cpufreq_cooling_device registered as a list whose head is represented by
	48	* cooling_cpufreq_list. In order to prevent corruption of this list a
	49	* mutex lock cooling_cpufreq_lock is used.
	50	*/
	51	struct cpufreq_cooling_device {
	52	int id;
	53	struct thermal_cooling_device *cool_dev;
	54	unsigned int cpufreq_state;
	55	unsigned int cpufreq_val;
	56	struct cpumask allowed_cpus;
	57	struct list_head node;
	58	};
	59	static LIST_HEAD(cooling_cpufreq_list);
	60	static DEFINE_IDR(cpufreq_idr);
160b7d80	61	static DEFINE_MUTEX(cooling_cpufreq_lock);
02361418	62
160b7d80	63	static unsigned int cpufreq_dev_count;
02361418 ADK	64
	65	/* notify_table passes value to the CPUFREQ_ADJUST callback function. */
	66	#define NOTIFY_INVALID NULL
a0f846c2	67	static struct cpufreq_cooling_device *notify_device;
02361418 ADK	68
	69	/**
	70	* get_idr - function to get a unique id.
	71	* @idr: struct idr * handle used to create a id.
	72	* @id: int * value generated by this function.
	73	*/
	74	static int get_idr(struct idr idr, int id)
	75	{
6deb69fa	76	int ret;
02361418 ADK	77
02361418 ADK	78	mutex_lock(&cooling_cpufreq_lock);
6deb69fa	79	ret = idr_alloc(idr, NULL, 0, 0, GFP_KERNEL);
02361418	80	mutex_unlock(&cooling_cpufreq_lock);
6deb69fa TH	81	if (unlikely(ret < 0))
	82	return ret;
	83	*id = ret;
02361418 ADK	84	return 0;
	85	}
	86
	87	/**
	88	* release_idr - function to free the unique id.
	89	* @idr: struct idr * handle used for creating the id.
	90	* @id: int value representing the unique id.
	91	*/
	92	static void release_idr(struct idr *idr, int id)
	93	{
	94	mutex_lock(&cooling_cpufreq_lock);
	95	idr_remove(idr, id);
	96	mutex_unlock(&cooling_cpufreq_lock);
	97	}
	98
	99	/* Below code defines functions to be used for cpufreq as cooling device */
	100
	101	/**
	102	* is_cpufreq_valid - function to check if a cpu has frequency transition policy.
	103	* @cpu: cpu for which check is needed.
	104	*/
	105	static int is_cpufreq_valid(int cpu)
	106	{
	107	struct cpufreq_policy policy;
	108	return !cpufreq_get_policy(&policy, cpu);
	109	}
	110
	111	/**
	112	* get_cpu_frequency - get the absolute value of frequency from level.
	113	* @cpu: cpu for which frequency is fetched.
475f41c3 ZR	114	* @level: level of frequency, equals cooling state of cpu cooling device
475f41c3 ZR	115	* e.g level=0 --> 1st MAX FREQ, level=1 ---> 2nd MAX FREQ, .... etc
02361418 ADK	116	*/
	117	static unsigned int get_cpu_frequency(unsigned int cpu, unsigned long level)
	118	{
	119	int ret = 0, i = 0;
	120	unsigned long level_index;
	121	bool descend = false;
	122	struct cpufreq_frequency_table *table =
	123	cpufreq_frequency_get_table(cpu);
	124	if (!table)
	125	return ret;
	126
	127	while (table[i].frequency != CPUFREQ_TABLE_END) {
	128	if (table[i].frequency == CPUFREQ_ENTRY_INVALID)
	129	continue;
	130
	131	/check if table in ascending or descending order/
	132	if ((table[i + 1].frequency != CPUFREQ_TABLE_END) &&
	133	(table[i + 1].frequency < table[i].frequency)
	134	&& !descend) {
	135	descend = true;
	136	}
	137
	138	/return if level matched and table in descending order/
	139	if (descend && i == level)
	140	return table[i].frequency;
	141	i++;
	142	}
	143	i--;
	144
	145	if (level > i \|\| descend)
	146	return ret;
	147	level_index = i - level;
	148
	149	/Scan the table in reverse order and match the level/
	150	while (i >= 0) {
	151	if (table[i].frequency == CPUFREQ_ENTRY_INVALID)
	152	continue;
	153	/return if level matched/
	154	if (i == level_index)
	155	return table[i].frequency;
	156	i--;
	157	}
	158	return ret;
	159	}
	160
	161	/**
	162	* cpufreq_apply_cooling - function to apply frequency clipping.
	163	* @cpufreq_device: cpufreq_cooling_device pointer containing frequency
	164	* clipping data.
	165	* @cooling_state: value of the cooling state.
	166	*/
	167	static int cpufreq_apply_cooling(struct cpufreq_cooling_device *cpufreq_device,
	168	unsigned long cooling_state)
	169	{
	170	unsigned int cpuid, clip_freq;
	171	struct cpumask *maskPtr = &cpufreq_device->allowed_cpus;
	172	unsigned int cpu = cpumask_any(maskPtr);
	173
	174
	175	/* Check if the old cooling action is same as new cooling action */
	176	if (cpufreq_device->cpufreq_state == cooling_state)
	177	return 0;
	178
	179	clip_freq = get_cpu_frequency(cpu, cooling_state);
180	if (!clip_freq)
181	return -EINVAL;
182
183	cpufreq_device->cpufreq_state = cooling_state;
184	cpufreq_device->cpufreq_val = clip_freq;
185	notify_device = cpufreq_device;
186
187	for_each_cpu(cpuid, maskPtr) {
188	if (is_cpufreq_valid(cpuid))
189	cpufreq_update_policy(cpuid);
190	}
191
192	notify_device = NOTIFY_INVALID;
193
194	return 0;
195	}
196
197	/**
198	* cpufreq_thermal_notifier - notifier callback for cpufreq policy change.
199	* @nb: struct notifier_block * with callback info.
200	* @event: value showing cpufreq event for which this function invoked.
201	* @data: callback-specific data
202	*/
203	static int cpufreq_thermal_notifier(struct notifier_block *nb,
204	unsigned long event, void *data)
205	{
206	struct cpufreq_policy *policy = data;
207	unsigned long max_freq = 0;
208
209	if (event != CPUFREQ_ADJUST \|\| notify_device == NOTIFY_INVALID)
210	return 0;
211
212	if (cpumask_test_cpu(policy->cpu, &notify_device->allowed_cpus))
213	max_freq = notify_device->cpufreq_val;
214
215	/* Never exceed user_policy.max*/
216	if (max_freq > policy->user_policy.max)
217	max_freq = policy->user_policy.max;
218
219	if (policy->max != max_freq)
220	cpufreq_verify_within_limits(policy, 0, max_freq);
221
222	return 0;
223	}
224
225	/*
226	* cpufreq cooling device callback functions are defined below
227	*/
228
229	/**
230	* cpufreq_get_max_state - callback function to get the max cooling state.
231	* @cdev: thermal cooling device pointer.
232	* @state: fill this variable with the max cooling state.
233	*/
234	static int cpufreq_get_max_state(struct thermal_cooling_device *cdev,
235	unsigned long *state)
236	{
160b7d80	237	struct cpufreq_cooling_device *cpufreq_device = cdev->devdata;
160b7d80	238	struct cpumask *maskPtr = &cpufreq_device->allowed_cpus;
02361418 ADK	239	unsigned int cpu;
02361418 ADK	240	struct cpufreq_frequency_table *table;
9c51b05a	241	unsigned long count = 0;
160b7d80	242	int i = 0;
02361418	243
02361418 ADK	244	cpu = cpumask_any(maskPtr);
	245	table = cpufreq_frequency_get_table(cpu);
	246	if (!table) {
	247	*state = 0;
160b7d80	248	return 0;
02361418 ADK	249	}
02361418 ADK	250
9c51b05a	251	for (i = 0; (table[i].frequency != CPUFREQ_TABLE_END); i++) {
02361418 ADK	252	if (table[i].frequency == CPUFREQ_ENTRY_INVALID)
02361418 ADK	253	continue;
9c51b05a	254	count++;
02361418	255	}
9c51b05a	256
	257	if (count > 0) {
	258	*state = --count;
160b7d80	259	return 0;
02361418 ADK	260	}
02361418 ADK	261
160b7d80	262	return -EINVAL;
02361418 ADK	263	}
	264
	265	/**
	266	* cpufreq_get_cur_state - callback function to get the current cooling state.
	267	* @cdev: thermal cooling device pointer.
	268	* @state: fill this variable with the current cooling state.
	269	*/
	270	static int cpufreq_get_cur_state(struct thermal_cooling_device *cdev,
	271	unsigned long *state)
	272	{
160b7d80	273	struct cpufreq_cooling_device *cpufreq_device = cdev->devdata;
02361418	274
160b7d80	275	*state = cpufreq_device->cpufreq_state;
160b7d80	276	return 0;
02361418 ADK	277	}
	278
	279	/**
	280	* cpufreq_set_cur_state - callback function to set the current cooling state.
	281	* @cdev: thermal cooling device pointer.
	282	* @state: set this variable to the current cooling state.
	283	*/
	284	static int cpufreq_set_cur_state(struct thermal_cooling_device *cdev,
	285	unsigned long state)
	286	{
160b7d80	287	struct cpufreq_cooling_device *cpufreq_device = cdev->devdata;
02361418	288
160b7d80	289	return cpufreq_apply_cooling(cpufreq_device, state);
02361418 ADK	290	}
	291
	292	/* Bind cpufreq callbacks to thermal cooling device ops */
	293	static struct thermal_cooling_device_ops const cpufreq_cooling_ops = {
	294	.get_max_state = cpufreq_get_max_state,
	295	.get_cur_state = cpufreq_get_cur_state,
	296	.set_cur_state = cpufreq_set_cur_state,
	297	};
	298
	299	/* Notifier for cpufreq policy change */
	300	static struct notifier_block thermal_cpufreq_notifier_block = {
	301	.notifier_call = cpufreq_thermal_notifier,
	302	};
	303
	304	/**
	305	* cpufreq_cooling_register - function to create cpufreq cooling device.
	306	* @clip_cpus: cpumask of cpus where the frequency constraints will happen.
	307	*/
	308	struct thermal_cooling_device *cpufreq_cooling_register(
3778ff5c	309	const struct cpumask *clip_cpus)
02361418 ADK	310	{
	311	struct thermal_cooling_device *cool_dev;
	312	struct cpufreq_cooling_device *cpufreq_dev = NULL;
160b7d80	313	unsigned int min = 0, max = 0;
02361418	314	char dev_name[THERMAL_NAME_LENGTH];
a4b6fec9	315	int ret = 0, i;
02361418 ADK	316	struct cpufreq_policy policy;
02361418 ADK	317
02361418 ADK	318	/Verify that all the clip cpus have same freq_min, freq_max limit/
	319	for_each_cpu(i, clip_cpus) {
	320	/continue if cpufreq policy not found and not return error/
	321	if (!cpufreq_get_policy(&policy, i))
	322	continue;
	323	if (min == 0 && max == 0) {
	324	min = policy.cpuinfo.min_freq;
	325	max = policy.cpuinfo.max_freq;
	326	} else {
	327	if (min != policy.cpuinfo.min_freq \|\|
	328	max != policy.cpuinfo.max_freq)
	329	return ERR_PTR(-EINVAL);
6b6519df	330	}
02361418 ADK	331	}
	332	cpufreq_dev = kzalloc(sizeof(struct cpufreq_cooling_device),
	333	GFP_KERNEL);
	334	if (!cpufreq_dev)
	335	return ERR_PTR(-ENOMEM);
	336
	337	cpumask_copy(&cpufreq_dev->allowed_cpus, clip_cpus);
	338
02361418 ADK	339	ret = get_idr(&cpufreq_idr, &cpufreq_dev->id);
	340	if (ret) {
	341	kfree(cpufreq_dev);
	342	return ERR_PTR(-EINVAL);
	343	}
	344
	345	sprintf(dev_name, "thermal-cpufreq-%d", cpufreq_dev->id);
	346
	347	cool_dev = thermal_cooling_device_register(dev_name, cpufreq_dev,
	348	&cpufreq_cooling_ops);
	349	if (!cool_dev) {
	350	release_idr(&cpufreq_idr, cpufreq_dev->id);
	351	kfree(cpufreq_dev);
	352	return ERR_PTR(-EINVAL);
	353	}
02361418 ADK	354	cpufreq_dev->cool_dev = cool_dev;
	355	cpufreq_dev->cpufreq_state = 0;
	356	mutex_lock(&cooling_cpufreq_lock);
02361418 ADK	357
	358	/* Register the notifier for first cpufreq cooling device */
	359	if (cpufreq_dev_count == 0)
	360	cpufreq_register_notifier(&thermal_cpufreq_notifier_block,
	361	CPUFREQ_POLICY_NOTIFIER);
160b7d80	362	cpufreq_dev_count++;
02361418 ADK	363
	364	mutex_unlock(&cooling_cpufreq_lock);
	365	return cool_dev;
	366	}
	367	EXPORT_SYMBOL(cpufreq_cooling_register);
	368
	369	/**
	370	* cpufreq_cooling_unregister - function to remove cpufreq cooling device.
	371	* @cdev: thermal cooling device pointer.
	372	*/
	373	void cpufreq_cooling_unregister(struct thermal_cooling_device *cdev)
	374	{
160b7d80	375	struct cpufreq_cooling_device *cpufreq_dev = cdev->devdata;
02361418 ADK	376
02361418 ADK	377	mutex_lock(&cooling_cpufreq_lock);
160b7d80	378	cpufreq_dev_count--;
02361418 ADK	379
02361418 ADK	380	/* Unregister the notifier for the last cpufreq cooling device */
160b7d80	381	if (cpufreq_dev_count == 0) {
02361418 ADK	382	cpufreq_unregister_notifier(&thermal_cpufreq_notifier_block,
	383	CPUFREQ_POLICY_NOTIFIER);
	384	}
	385	mutex_unlock(&cooling_cpufreq_lock);
160b7d80	386
02361418 ADK	387	thermal_cooling_device_unregister(cpufreq_dev->cool_dev);
02361418 ADK	388	release_idr(&cpufreq_idr, cpufreq_dev->id);
02361418 ADK	389	kfree(cpufreq_dev);
	390	}
	391	EXPORT_SYMBOL(cpufreq_cooling_unregister);