[deliverable/linux.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/module.h>
#include <linux/thermal.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 - data for cooling device with cpufreq
 * @id: unique integer value corresponding to each cpufreq_cooling_device
 *	registered.
 * @cool_dev: thermal_cooling_device pointer to keep track of the
 *	registered 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 frequency transitioning capability.
 * @cpu: cpu for which check is needed.
 *
 * This function will check the current state of the system if
 * it is capable of changing the frequency for a given @cpu.
 *
 * Return: 0 if the system is not currently capable of changing
 * the frequency of given cpu. !0 in case the frequency is changeable.
 */
static int is_cpufreq_valid(int cpu)
{
	struct cpufreq_policy policy;
	return !cpufreq_get_policy(&policy, cpu);
}

enum cpufreq_cooling_property {
	GET_LEVEL,
	GET_FREQ,
	GET_MAXL,
};

/*
 * this is the common function to
 * 1. get maximum cpu cooling states
 * 2. translate frequency to cooling state
 * 3. translate cooling state to frequency
 * Note that the code may be not in good shape
 * but it is written in this way in order to:
 * a) reduce duplicate code as most of the code can be shared.
 * b) make sure the logic is consistent when translating between
 *    cooling states and frequencies.
*/
static int get_property(unsigned int cpu, unsigned long input,
	unsigned int* output, enum cpufreq_cooling_property property)
{
	int i, j;
	unsigned long max_level = 0, level = 0;
	unsigned int freq = CPUFREQ_ENTRY_INVALID;
	int descend = -1;
	struct cpufreq_frequency_table *table =
					cpufreq_frequency_get_table(cpu);
	
	if (!output)
		return -EINVAL;

	if (!table)
		return -EINVAL;

	
	for (i = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
		/* ignore invalid entries */
		if (table[i].frequency == CPUFREQ_ENTRY_INVALID)
			continue;

		/* ignore duplicate entry */
		if (freq == table[i].frequency)
			continue;

		/* get the frequency order */
		if (freq != CPUFREQ_ENTRY_INVALID && descend != -1)
			descend = !!(freq > table[i].frequency);

		freq = table[i].frequency;
		max_level++;
	}

	/* get max level */
	if (property == GET_MAXL) {
		*output = (unsigned int)max_level;
		return 0;
	}

	if (property == GET_FREQ)
		level = descend ? input : (max_level - input -1);


	for (i = 0, j = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
		/* ignore invalid entry */
		if (table[i].frequency == CPUFREQ_ENTRY_INVALID)
			continue;

		/* ignore duplicate entry */
		if (freq == table[i].frequency)
			continue;

		/* now we have a valid frequency entry */
		freq = table[i].frequency;

		if (property == GET_LEVEL && (unsigned int)input == freq) {
			/* get level by frequency */
			*output = descend ? j : (max_level - j - 1);
			return 0;
		}
		if (property == GET_FREQ && level == j) {
			/* get frequency by level */
			*output = freq;
			return 0;
		}
		j++;
	}
	return -EINVAL;
}

unsigned long cpufreq_cooling_get_level(unsigned int cpu, unsigned int freq)
{
	unsigned int val;

	if (get_property(cpu, (unsigned long)freq, &val, GET_LEVEL))
		return THERMAL_CSTATE_INVALID;
	return (unsigned long)val;
}
EXPORT_SYMBOL_GPL(cpufreq_cooling_get_level);

/**
 * 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;
	unsigned int freq;

	ret = get_property(cpu, level, &freq, GET_FREQ);
	if (ret)
		return 0;
	return freq;
}

/**
 * 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 *mask = &cpufreq_device->allowed_cpus;
	unsigned int cpu = cpumask_any(mask);


	/* 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, mask) {
		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 *mask = &cpufreq_device->allowed_cpus;
	unsigned int cpu;
	unsigned int count = 0;
	int ret;

	cpu = cpumask_any(mask);

	ret = get_property(cpu, 0, &count, GET_MAXL);

	if (count > 0)
		*state = count;

	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)
{
	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_GPL(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_GPL(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	*/
02361418 ADK	23	#include <linux/module.h>
02361418 ADK	24	#include <linux/thermal.h>
02361418 ADK	25	#include <linux/cpufreq.h>
	26	#include <linux/err.h>
	27	#include <linux/slab.h>
	28	#include <linux/cpu.h>
	29	#include <linux/cpu_cooling.h>
	30
	31	/**
3b3c0748	32	* struct cpufreq_cooling_device - data for cooling device with cpufreq
02361418 ADK	33	* @id: unique integer value corresponding to each cpufreq_cooling_device
02361418 ADK	34	* registered.
3b3c0748 EV	35	* @cool_dev: thermal_cooling_device pointer to keep track of the
3b3c0748 EV	36	* registered cooling device.
02361418 ADK	37	* @cpufreq_state: integer value representing the current state of cpufreq
	38	* cooling devices.
	39	* @cpufreq_val: integer value representing the absolute value of the clipped
	40	* frequency.
	41	* @allowed_cpus: all the cpus involved for this cpufreq_cooling_device.
	42	* @node: list_head to link all cpufreq_cooling_device together.
	43	*
	44	* This structure is required for keeping information of each
	45	* cpufreq_cooling_device registered as a list whose head is represented by
	46	* cooling_cpufreq_list. In order to prevent corruption of this list a
	47	* mutex lock cooling_cpufreq_lock is used.
	48	*/
	49	struct cpufreq_cooling_device {
	50	int id;
	51	struct thermal_cooling_device *cool_dev;
	52	unsigned int cpufreq_state;
	53	unsigned int cpufreq_val;
	54	struct cpumask allowed_cpus;
	55	struct list_head node;
	56	};
	57	static LIST_HEAD(cooling_cpufreq_list);
	58	static DEFINE_IDR(cpufreq_idr);
160b7d80	59	static DEFINE_MUTEX(cooling_cpufreq_lock);
02361418	60
160b7d80	61	static unsigned int cpufreq_dev_count;
02361418 ADK	62
	63	/* notify_table passes value to the CPUFREQ_ADJUST callback function. */
	64	#define NOTIFY_INVALID NULL
a0f846c2	65	static struct cpufreq_cooling_device *notify_device;
02361418 ADK	66
	67	/**
	68	* get_idr - function to get a unique id.
	69	* @idr: struct idr * handle used to create a id.
	70	* @id: int * value generated by this function.
	71	*/
	72	static int get_idr(struct idr idr, int id)
	73	{
6deb69fa	74	int ret;
02361418 ADK	75
02361418 ADK	76	mutex_lock(&cooling_cpufreq_lock);
6deb69fa	77	ret = idr_alloc(idr, NULL, 0, 0, GFP_KERNEL);
02361418	78	mutex_unlock(&cooling_cpufreq_lock);
6deb69fa TH	79	if (unlikely(ret < 0))
	80	return ret;
	81	*id = ret;
02361418 ADK	82	return 0;
	83	}
	84
	85	/**
	86	* release_idr - function to free the unique id.
	87	* @idr: struct idr * handle used for creating the id.
	88	* @id: int value representing the unique id.
	89	*/
	90	static void release_idr(struct idr *idr, int id)
	91	{
	92	mutex_lock(&cooling_cpufreq_lock);
	93	idr_remove(idr, id);
	94	mutex_unlock(&cooling_cpufreq_lock);
	95	}
	96
	97	/* Below code defines functions to be used for cpufreq as cooling device */
	98
	99	/**
82b9ee40	100	* is_cpufreq_valid - function to check frequency transitioning capability.
02361418	101	* @cpu: cpu for which check is needed.
82b9ee40 EV	102	*
	103	* This function will check the current state of the system if
	104	* it is capable of changing the frequency for a given @cpu.
	105	*
	106	* Return: 0 if the system is not currently capable of changing
	107	* the frequency of given cpu. !0 in case the frequency is changeable.
02361418 ADK	108	*/
	109	static int is_cpufreq_valid(int cpu)
	110	{
	111	struct cpufreq_policy policy;
	112	return !cpufreq_get_policy(&policy, cpu);
	113	}
	114
fc35b35c ZR	115	enum cpufreq_cooling_property {
	116	GET_LEVEL,
	117	GET_FREQ,
	118	GET_MAXL,
	119	};
	120
	121	/*
	122	* this is the common function to
	123	* 1. get maximum cpu cooling states
	124	* 2. translate frequency to cooling state
	125	* 3. translate cooling state to frequency
	126	* Note that the code may be not in good shape
	127	* but it is written in this way in order to:
	128	* a) reduce duplicate code as most of the code can be shared.
	129	* b) make sure the logic is consistent when translating between
	130	* cooling states and frequencies.
	131	*/
	132	static int get_property(unsigned int cpu, unsigned long input,
	133	unsigned int* output, enum cpufreq_cooling_property property)
02361418	134	{
fc35b35c	135	int i, j;
4469b997	136	unsigned long max_level = 0, level = 0;
fc35b35c ZR	137	unsigned int freq = CPUFREQ_ENTRY_INVALID;
fc35b35c ZR	138	int descend = -1;
02361418 ADK	139	struct cpufreq_frequency_table *table =
02361418 ADK	140	cpufreq_frequency_get_table(cpu);
fc35b35c ZR	141
	142	if (!output)
	143	return -EINVAL;
	144
02361418	145	if (!table)
fc35b35c	146	return -EINVAL;
02361418	147
fc35b35c ZR	148
	149	for (i = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
	150	/* ignore invalid entries */
02361418 ADK	151	if (table[i].frequency == CPUFREQ_ENTRY_INVALID)
	152	continue;
	153
fc35b35c ZR	154	/* ignore duplicate entry */
	155	if (freq == table[i].frequency)
	156	continue;
	157
	158	/* get the frequency order */
	159	if (freq != CPUFREQ_ENTRY_INVALID && descend != -1)
	160	descend = !!(freq > table[i].frequency);
02361418	161
fc35b35c ZR	162	freq = table[i].frequency;
fc35b35c ZR	163	max_level++;
02361418	164	}
02361418	165
fc35b35c ZR	166	/* get max level */
	167	if (property == GET_MAXL) {
	168	*output = (unsigned int)max_level;
	169	return 0;
	170	}
02361418	171
fc35b35c ZR	172	if (property == GET_FREQ)
	173	level = descend ? input : (max_level - input -1);
	174
02361418	175
fc35b35c ZR	176	for (i = 0, j = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
fc35b35c ZR	177	/* ignore invalid entry */
02361418 ADK	178	if (table[i].frequency == CPUFREQ_ENTRY_INVALID)
02361418 ADK	179	continue;
fc35b35c ZR	180
	181	/* ignore duplicate entry */
	182	if (freq == table[i].frequency)
	183	continue;
	184
	185	/* now we have a valid frequency entry */
	186	freq = table[i].frequency;
	187
	188	if (property == GET_LEVEL && (unsigned int)input == freq) {
	189	/* get level by frequency */
	190	*output = descend ? j : (max_level - j - 1);
	191	return 0;
	192	}
	193	if (property == GET_FREQ && level == j) {
	194	/* get frequency by level */
	195	*output = freq;
	196	return 0;
	197	}
	198	j++;
02361418	199	}
fc35b35c ZR	200	return -EINVAL;
	201	}
	202
57df8106 ZR	203	unsigned long cpufreq_cooling_get_level(unsigned int cpu, unsigned int freq)
	204	{
	205	unsigned int val;
	206
	207	if (get_property(cpu, (unsigned long)freq, &val, GET_LEVEL))
	208	return THERMAL_CSTATE_INVALID;
	209	return (unsigned long)val;
	210	}
243dbd9c	211	EXPORT_SYMBOL_GPL(cpufreq_cooling_get_level);
57df8106	212
fc35b35c ZR	213	/**
	214	* get_cpu_frequency - get the absolute value of frequency from level.
	215	* @cpu: cpu for which frequency is fetched.
	216	* @level: level of frequency, equals cooling state of cpu cooling device
	217	* e.g level=0 --> 1st MAX FREQ, level=1 ---> 2nd MAX FREQ, .... etc
	218	*/
	219	static unsigned int get_cpu_frequency(unsigned int cpu, unsigned long level)
	220	{
	221	int ret = 0;
	222	unsigned int freq;
	223
	224	ret = get_property(cpu, level, &freq, GET_FREQ);
	225	if (ret)
	226	return 0;
	227	return freq;
02361418 ADK	228	}
	229
	230	/**
	231	* cpufreq_apply_cooling - function to apply frequency clipping.
	232	* @cpufreq_device: cpufreq_cooling_device pointer containing frequency
	233	* clipping data.
	234	* @cooling_state: value of the cooling state.
	235	*/
	236	static int cpufreq_apply_cooling(struct cpufreq_cooling_device *cpufreq_device,
	237	unsigned long cooling_state)
	238	{
	239	unsigned int cpuid, clip_freq;
bde00663 LNM	240	struct cpumask *mask = &cpufreq_device->allowed_cpus;
bde00663 LNM	241	unsigned int cpu = cpumask_any(mask);
02361418 ADK	242
	243
	244	/* Check if the old cooling action is same as new cooling action */
	245	if (cpufreq_device->cpufreq_state == cooling_state)
	246	return 0;
	247
	248	clip_freq = get_cpu_frequency(cpu, cooling_state);
	249	if (!clip_freq)
	250	return -EINVAL;
	251
	252	cpufreq_device->cpufreq_state = cooling_state;
	253	cpufreq_device->cpufreq_val = clip_freq;
	254	notify_device = cpufreq_device;
	255
bde00663	256	for_each_cpu(cpuid, mask) {
02361418 ADK	257	if (is_cpufreq_valid(cpuid))
	258	cpufreq_update_policy(cpuid);
	259	}
	260
	261	notify_device = NOTIFY_INVALID;
	262
	263	return 0;
	264	}
	265
	266	/**
	267	* cpufreq_thermal_notifier - notifier callback for cpufreq policy change.
	268	* @nb: struct notifier_block * with callback info.
	269	* @event: value showing cpufreq event for which this function invoked.
	270	* @data: callback-specific data
	271	*/
	272	static int cpufreq_thermal_notifier(struct notifier_block *nb,
	273	unsigned long event, void *data)
	274	{
	275	struct cpufreq_policy *policy = data;
	276	unsigned long max_freq = 0;
	277
	278	if (event != CPUFREQ_ADJUST \|\| notify_device == NOTIFY_INVALID)
	279	return 0;
	280
	281	if (cpumask_test_cpu(policy->cpu, &notify_device->allowed_cpus))
	282	max_freq = notify_device->cpufreq_val;
	283
	284	/* Never exceed user_policy.max*/
	285	if (max_freq > policy->user_policy.max)
	286	max_freq = policy->user_policy.max;
	287
	288	if (policy->max != max_freq)
	289	cpufreq_verify_within_limits(policy, 0, max_freq);
	290
	291	return 0;
	292	}
	293
	294	/*
	295	* cpufreq cooling device callback functions are defined below
	296	*/
	297
	298	/**
	299	* cpufreq_get_max_state - callback function to get the max cooling state.
	300	* @cdev: thermal cooling device pointer.
	301	* @state: fill this variable with the max cooling state.
	302	*/
	303	static int cpufreq_get_max_state(struct thermal_cooling_device *cdev,
	304	unsigned long *state)
	305	{
160b7d80	306	struct cpufreq_cooling_device *cpufreq_device = cdev->devdata;
bde00663	307	struct cpumask *mask = &cpufreq_device->allowed_cpus;
02361418	308	unsigned int cpu;
4f89038f	309	unsigned int count = 0;
fc35b35c	310	int ret;
02361418	311
bde00663	312	cpu = cpumask_any(mask);
02361418	313
4f89038f	314	ret = get_property(cpu, 0, &count, GET_MAXL);
9c51b05a	315
fc35b35c ZR	316	if (count > 0)
fc35b35c ZR	317	*state = count;
02361418	318
fc35b35c	319	return ret;
02361418 ADK	320	}
	321
	322	/**
	323	* cpufreq_get_cur_state - callback function to get the current cooling state.
	324	* @cdev: thermal cooling device pointer.
	325	* @state: fill this variable with the current cooling state.
	326	*/
	327	static int cpufreq_get_cur_state(struct thermal_cooling_device *cdev,
	328	unsigned long *state)
	329	{
160b7d80	330	struct cpufreq_cooling_device *cpufreq_device = cdev->devdata;
02361418	331
160b7d80	332	*state = cpufreq_device->cpufreq_state;
160b7d80	333	return 0;
02361418 ADK	334	}
	335
	336	/**
	337	* cpufreq_set_cur_state - callback function to set the current cooling state.
	338	* @cdev: thermal cooling device pointer.
	339	* @state: set this variable to the current cooling state.
	340	*/
	341	static int cpufreq_set_cur_state(struct thermal_cooling_device *cdev,
	342	unsigned long state)
	343	{
160b7d80	344	struct cpufreq_cooling_device *cpufreq_device = cdev->devdata;
02361418	345
160b7d80	346	return cpufreq_apply_cooling(cpufreq_device, state);
02361418 ADK	347	}
	348
	349	/* Bind cpufreq callbacks to thermal cooling device ops */
	350	static struct thermal_cooling_device_ops const cpufreq_cooling_ops = {
	351	.get_max_state = cpufreq_get_max_state,
	352	.get_cur_state = cpufreq_get_cur_state,
	353	.set_cur_state = cpufreq_set_cur_state,
	354	};
	355
	356	/* Notifier for cpufreq policy change */
	357	static struct notifier_block thermal_cpufreq_notifier_block = {
	358	.notifier_call = cpufreq_thermal_notifier,
	359	};
	360
	361	/**
	362	* cpufreq_cooling_register - function to create cpufreq cooling device.
	363	* @clip_cpus: cpumask of cpus where the frequency constraints will happen.
	364	*/
	365	struct thermal_cooling_device *cpufreq_cooling_register(
3778ff5c	366	const struct cpumask *clip_cpus)
02361418 ADK	367	{
	368	struct thermal_cooling_device *cool_dev;
	369	struct cpufreq_cooling_device *cpufreq_dev = NULL;
160b7d80	370	unsigned int min = 0, max = 0;
02361418	371	char dev_name[THERMAL_NAME_LENGTH];
a4b6fec9	372	int ret = 0, i;
02361418 ADK	373	struct cpufreq_policy policy;
02361418 ADK	374
02361418 ADK	375	/Verify that all the clip cpus have same freq_min, freq_max limit/
	376	for_each_cpu(i, clip_cpus) {
	377	/continue if cpufreq policy not found and not return error/
	378	if (!cpufreq_get_policy(&policy, i))
	379	continue;
	380	if (min == 0 && max == 0) {
	381	min = policy.cpuinfo.min_freq;
	382	max = policy.cpuinfo.max_freq;
	383	} else {
	384	if (min != policy.cpuinfo.min_freq \|\|
	385	max != policy.cpuinfo.max_freq)
	386	return ERR_PTR(-EINVAL);
6b6519df	387	}
02361418 ADK	388	}
	389	cpufreq_dev = kzalloc(sizeof(struct cpufreq_cooling_device),
	390	GFP_KERNEL);
	391	if (!cpufreq_dev)
	392	return ERR_PTR(-ENOMEM);
	393
	394	cpumask_copy(&cpufreq_dev->allowed_cpus, clip_cpus);
	395
02361418 ADK	396	ret = get_idr(&cpufreq_idr, &cpufreq_dev->id);
	397	if (ret) {
	398	kfree(cpufreq_dev);
	399	return ERR_PTR(-EINVAL);
	400	}
	401
	402	sprintf(dev_name, "thermal-cpufreq-%d", cpufreq_dev->id);
	403
	404	cool_dev = thermal_cooling_device_register(dev_name, cpufreq_dev,
	405	&cpufreq_cooling_ops);
	406	if (!cool_dev) {
	407	release_idr(&cpufreq_idr, cpufreq_dev->id);
	408	kfree(cpufreq_dev);
	409	return ERR_PTR(-EINVAL);
	410	}
02361418 ADK	411	cpufreq_dev->cool_dev = cool_dev;
	412	cpufreq_dev->cpufreq_state = 0;
	413	mutex_lock(&cooling_cpufreq_lock);
02361418 ADK	414
	415	/* Register the notifier for first cpufreq cooling device */
	416	if (cpufreq_dev_count == 0)
	417	cpufreq_register_notifier(&thermal_cpufreq_notifier_block,
	418	CPUFREQ_POLICY_NOTIFIER);
160b7d80	419	cpufreq_dev_count++;
02361418 ADK	420
	421	mutex_unlock(&cooling_cpufreq_lock);
	422	return cool_dev;
	423	}
243dbd9c	424	EXPORT_SYMBOL_GPL(cpufreq_cooling_register);
02361418 ADK	425
	426	/**
	427	* cpufreq_cooling_unregister - function to remove cpufreq cooling device.
	428	* @cdev: thermal cooling device pointer.
	429	*/
	430	void cpufreq_cooling_unregister(struct thermal_cooling_device *cdev)
	431	{
160b7d80	432	struct cpufreq_cooling_device *cpufreq_dev = cdev->devdata;
02361418 ADK	433
02361418 ADK	434	mutex_lock(&cooling_cpufreq_lock);
160b7d80	435	cpufreq_dev_count--;
02361418 ADK	436
02361418 ADK	437	/* Unregister the notifier for the last cpufreq cooling device */
160b7d80	438	if (cpufreq_dev_count == 0) {
02361418 ADK	439	cpufreq_unregister_notifier(&thermal_cpufreq_notifier_block,
	440	CPUFREQ_POLICY_NOTIFIER);
	441	}
	442	mutex_unlock(&cooling_cpufreq_lock);
160b7d80	443
02361418 ADK	444	thermal_cooling_device_unregister(cpufreq_dev->cool_dev);
02361418 ADK	445	release_idr(&cpufreq_idr, cpufreq_dev->id);
02361418 ADK	446	kfree(cpufreq_dev);
02361418 ADK	447	}
243dbd9c	448	EXPORT_SYMBOL_GPL(cpufreq_cooling_unregister);