[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/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 struct mutex cooling_cpufreq_lock;

/* notify_table passes value to the CPUFREQ_ADJUST callback function. */
#define NOTIFY_INVALID NULL
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 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_IDR_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);
}

/* 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 of the CPU
 *	e.g level=1 --> 1st MAX FREQ, LEVEL=2 ---> 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)
{
	int ret = -EINVAL, i = 0;
	struct cpufreq_cooling_device *cpufreq_device;
	struct cpumask *maskPtr;
	unsigned int cpu;
	struct cpufreq_frequency_table *table;
	unsigned long count = 0;

	mutex_lock(&cooling_cpufreq_lock);
	list_for_each_entry(cpufreq_device, &cooling_cpufreq_list, node) {
		if (cpufreq_device && cpufreq_device->cool_dev == cdev)
			break;
	}
	if (cpufreq_device == NULL)
		goto return_get_max_state;

	maskPtr = &cpufreq_device->allowed_cpus;
	cpu = cpumask_any(maskPtr);
	table = cpufreq_frequency_get_table(cpu);
	if (!table) {
		*state = 0;
		ret = 0;
		goto return_get_max_state;
	}

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

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

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

	list_for_each_entry(cpufreq_dev, &cooling_cpufreq_list, node)
		cpufreq_dev_count++;

	/*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);

	if (cpufreq_dev_count == 0)
		mutex_init(&cooling_cpufreq_lock);

	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);
	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);
	if (cpufreq_dev_count == 1)
		mutex_destroy(&cooling_cpufreq_lock);
	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);
	61
	62	static struct mutex cooling_cpufreq_lock;
	63
	64	/* notify_table passes value to the CPUFREQ_ADJUST callback function. */
65	#define NOTIFY_INVALID NULL
66	struct cpufreq_cooling_device *notify_device;
67
68	/**
69	* get_idr - function to get a unique id.
70	* @idr: struct idr * handle used to create a id.
71	* @id: int * value generated by this function.
72	*/
73	static int get_idr(struct idr idr, int id)
74	{
75	int err;
76	again:
77	if (unlikely(idr_pre_get(idr, GFP_KERNEL) == 0))
78	return -ENOMEM;
79
80	mutex_lock(&cooling_cpufreq_lock);
81	err = idr_get_new(idr, NULL, id);
82	mutex_unlock(&cooling_cpufreq_lock);
83
84	if (unlikely(err == -EAGAIN))
85	goto again;
86	else if (unlikely(err))
87	return err;
88
29b19e25	89	id = id & MAX_IDR_MASK;
02361418 ADK	90	return 0;
	91	}
	92
	93	/**
	94	* release_idr - function to free the unique id.
	95	* @idr: struct idr * handle used for creating the id.
	96	* @id: int value representing the unique id.
	97	*/
	98	static void release_idr(struct idr *idr, int id)
	99	{
	100	mutex_lock(&cooling_cpufreq_lock);
	101	idr_remove(idr, id);
	102	mutex_unlock(&cooling_cpufreq_lock);
	103	}
	104
	105	/* Below code defines functions to be used for cpufreq as cooling device */
	106
	107	/**
	108	* is_cpufreq_valid - function to check if a cpu has frequency transition policy.
	109	* @cpu: cpu for which check is needed.
	110	*/
	111	static int is_cpufreq_valid(int cpu)
	112	{
	113	struct cpufreq_policy policy;
	114	return !cpufreq_get_policy(&policy, cpu);
	115	}
	116
	117	/**
	118	* get_cpu_frequency - get the absolute value of frequency from level.
	119	* @cpu: cpu for which frequency is fetched.
	120	* @level: level of frequency of the CPU
	121	* e.g level=1 --> 1st MAX FREQ, LEVEL=2 ---> 2nd MAX FREQ, .... etc
	122	*/
	123	static unsigned int get_cpu_frequency(unsigned int cpu, unsigned long level)
	124	{
	125	int ret = 0, i = 0;
	126	unsigned long level_index;
	127	bool descend = false;
	128	struct cpufreq_frequency_table *table =
	129	cpufreq_frequency_get_table(cpu);
	130	if (!table)
	131	return ret;
	132
	133	while (table[i].frequency != CPUFREQ_TABLE_END) {
	134	if (table[i].frequency == CPUFREQ_ENTRY_INVALID)
	135	continue;
	136
	137	/check if table in ascending or descending order/
	138	if ((table[i + 1].frequency != CPUFREQ_TABLE_END) &&
	139	(table[i + 1].frequency < table[i].frequency)
	140	&& !descend) {
	141	descend = true;
	142	}
	143
	144	/return if level matched and table in descending order/
	145	if (descend && i == level)
	146	return table[i].frequency;
	147	i++;
	148	}
	149	i--;
	150
	151	if (level > i \|\| descend)
	152	return ret;
	153	level_index = i - level;
154
155	/Scan the table in reverse order and match the level/
156	while (i >= 0) {
157	if (table[i].frequency == CPUFREQ_ENTRY_INVALID)
158	continue;
159	/return if level matched/
160	if (i == level_index)
161	return table[i].frequency;
162	i--;
163	}
164	return ret;
165	}
166
167	/**
168	* cpufreq_apply_cooling - function to apply frequency clipping.
169	* @cpufreq_device: cpufreq_cooling_device pointer containing frequency
170	* clipping data.
171	* @cooling_state: value of the cooling state.
172	*/
173	static int cpufreq_apply_cooling(struct cpufreq_cooling_device *cpufreq_device,
174	unsigned long cooling_state)
175	{
176	unsigned int cpuid, clip_freq;
177	struct cpumask *maskPtr = &cpufreq_device->allowed_cpus;
178	unsigned int cpu = cpumask_any(maskPtr);
179
180
181	/* Check if the old cooling action is same as new cooling action */
182	if (cpufreq_device->cpufreq_state == cooling_state)
183	return 0;
184
185	clip_freq = get_cpu_frequency(cpu, cooling_state);
186	if (!clip_freq)
187	return -EINVAL;
188
189	cpufreq_device->cpufreq_state = cooling_state;
190	cpufreq_device->cpufreq_val = clip_freq;
191	notify_device = cpufreq_device;
192
193	for_each_cpu(cpuid, maskPtr) {
194	if (is_cpufreq_valid(cpuid))
195	cpufreq_update_policy(cpuid);
196	}
197
198	notify_device = NOTIFY_INVALID;
199
200	return 0;
201	}
202
203	/**
204	* cpufreq_thermal_notifier - notifier callback for cpufreq policy change.
205	* @nb: struct notifier_block * with callback info.
206	* @event: value showing cpufreq event for which this function invoked.
207	* @data: callback-specific data
208	*/
209	static int cpufreq_thermal_notifier(struct notifier_block *nb,
210	unsigned long event, void *data)
211	{
212	struct cpufreq_policy *policy = data;
213	unsigned long max_freq = 0;
214
215	if (event != CPUFREQ_ADJUST \|\| notify_device == NOTIFY_INVALID)
216	return 0;
217
218	if (cpumask_test_cpu(policy->cpu, &notify_device->allowed_cpus))
219	max_freq = notify_device->cpufreq_val;
220
221	/* Never exceed user_policy.max*/
222	if (max_freq > policy->user_policy.max)
223	max_freq = policy->user_policy.max;
224
225	if (policy->max != max_freq)
226	cpufreq_verify_within_limits(policy, 0, max_freq);
227
228	return 0;
229	}
230
231	/*
232	* cpufreq cooling device callback functions are defined below
233	*/
234
235	/**
236	* cpufreq_get_max_state - callback function to get the max cooling state.
237	* @cdev: thermal cooling device pointer.
238	* @state: fill this variable with the max cooling state.
239	*/
240	static int cpufreq_get_max_state(struct thermal_cooling_device *cdev,
241	unsigned long *state)
242	{
243	int ret = -EINVAL, i = 0;
244	struct cpufreq_cooling_device *cpufreq_device;
245	struct cpumask *maskPtr;
246	unsigned int cpu;
247	struct cpufreq_frequency_table *table;
9c51b05a	248	unsigned long count = 0;
02361418 ADK	249
	250	mutex_lock(&cooling_cpufreq_lock);
	251	list_for_each_entry(cpufreq_device, &cooling_cpufreq_list, node) {
	252	if (cpufreq_device && cpufreq_device->cool_dev == cdev)
	253	break;
	254	}
	255	if (cpufreq_device == NULL)
	256	goto return_get_max_state;
	257
	258	maskPtr = &cpufreq_device->allowed_cpus;
	259	cpu = cpumask_any(maskPtr);
	260	table = cpufreq_frequency_get_table(cpu);
	261	if (!table) {
	262	*state = 0;
	263	ret = 0;
	264	goto return_get_max_state;
	265	}
	266
9c51b05a	267	for (i = 0; (table[i].frequency != CPUFREQ_TABLE_END); i++) {
02361418 ADK	268	if (table[i].frequency == CPUFREQ_ENTRY_INVALID)
02361418 ADK	269	continue;
9c51b05a	270	count++;
02361418	271	}
9c51b05a	272
	273	if (count > 0) {
	274	*state = --count;
02361418 ADK	275	ret = 0;
	276	}
	277
	278	return_get_max_state:
	279	mutex_unlock(&cooling_cpufreq_lock);
	280	return ret;
	281	}
	282
	283	/**
	284	* cpufreq_get_cur_state - callback function to get the current cooling state.
	285	* @cdev: thermal cooling device pointer.
	286	* @state: fill this variable with the current cooling state.
	287	*/
	288	static int cpufreq_get_cur_state(struct thermal_cooling_device *cdev,
	289	unsigned long *state)
	290	{
	291	int ret = -EINVAL;
	292	struct cpufreq_cooling_device *cpufreq_device;
	293
	294	mutex_lock(&cooling_cpufreq_lock);
	295	list_for_each_entry(cpufreq_device, &cooling_cpufreq_list, node) {
	296	if (cpufreq_device && cpufreq_device->cool_dev == cdev) {
	297	*state = cpufreq_device->cpufreq_state;
	298	ret = 0;
	299	break;
	300	}
	301	}
	302	mutex_unlock(&cooling_cpufreq_lock);
	303
	304	return ret;
	305	}
	306
	307	/**
	308	* cpufreq_set_cur_state - callback function to set the current cooling state.
	309	* @cdev: thermal cooling device pointer.
	310	* @state: set this variable to the current cooling state.
	311	*/
	312	static int cpufreq_set_cur_state(struct thermal_cooling_device *cdev,
	313	unsigned long state)
	314	{
	315	int ret = -EINVAL;
	316	struct cpufreq_cooling_device *cpufreq_device;
	317
	318	mutex_lock(&cooling_cpufreq_lock);
	319	list_for_each_entry(cpufreq_device, &cooling_cpufreq_list, node) {
	320	if (cpufreq_device && cpufreq_device->cool_dev == cdev) {
	321	ret = 0;
	322	break;
	323	}
	324	}
	325	if (!ret)
	326	ret = cpufreq_apply_cooling(cpufreq_device, state);
	327
	328	mutex_unlock(&cooling_cpufreq_lock);
	329
	330	return ret;
	331	}
	332
	333	/* Bind cpufreq callbacks to thermal cooling device ops */
	334	static struct thermal_cooling_device_ops const cpufreq_cooling_ops = {
	335	.get_max_state = cpufreq_get_max_state,
	336	.get_cur_state = cpufreq_get_cur_state,
	337	.set_cur_state = cpufreq_set_cur_state,
	338	};
339
340	/* Notifier for cpufreq policy change */
341	static struct notifier_block thermal_cpufreq_notifier_block = {
342	.notifier_call = cpufreq_thermal_notifier,
343	};
344
345	/**
346	* cpufreq_cooling_register - function to create cpufreq cooling device.
347	* @clip_cpus: cpumask of cpus where the frequency constraints will happen.
348	*/
349	struct thermal_cooling_device *cpufreq_cooling_register(
350	struct cpumask *clip_cpus)
351	{
352	struct thermal_cooling_device *cool_dev;
353	struct cpufreq_cooling_device *cpufreq_dev = NULL;
354	unsigned int cpufreq_dev_count = 0, min = 0, max = 0;
355	char dev_name[THERMAL_NAME_LENGTH];
a4b6fec9	356	int ret = 0, i;
02361418 ADK	357	struct cpufreq_policy policy;
	358
	359	list_for_each_entry(cpufreq_dev, &cooling_cpufreq_list, node)
	360	cpufreq_dev_count++;
	361
	362	/Verify that all the clip cpus have same freq_min, freq_max limit/
	363	for_each_cpu(i, clip_cpus) {
	364	/continue if cpufreq policy not found and not return error/
	365	if (!cpufreq_get_policy(&policy, i))
	366	continue;
	367	if (min == 0 && max == 0) {
	368	min = policy.cpuinfo.min_freq;
	369	max = policy.cpuinfo.max_freq;
	370	} else {
	371	if (min != policy.cpuinfo.min_freq \|\|
	372	max != policy.cpuinfo.max_freq)
	373	return ERR_PTR(-EINVAL);
6b6519df	374	}
02361418 ADK	375	}
	376	cpufreq_dev = kzalloc(sizeof(struct cpufreq_cooling_device),
	377	GFP_KERNEL);
	378	if (!cpufreq_dev)
	379	return ERR_PTR(-ENOMEM);
	380
	381	cpumask_copy(&cpufreq_dev->allowed_cpus, clip_cpus);
	382
	383	if (cpufreq_dev_count == 0)
	384	mutex_init(&cooling_cpufreq_lock);
	385
	386	ret = get_idr(&cpufreq_idr, &cpufreq_dev->id);
	387	if (ret) {
	388	kfree(cpufreq_dev);
	389	return ERR_PTR(-EINVAL);
	390	}
	391
	392	sprintf(dev_name, "thermal-cpufreq-%d", cpufreq_dev->id);
	393
	394	cool_dev = thermal_cooling_device_register(dev_name, cpufreq_dev,
	395	&cpufreq_cooling_ops);
	396	if (!cool_dev) {
	397	release_idr(&cpufreq_idr, cpufreq_dev->id);
	398	kfree(cpufreq_dev);
	399	return ERR_PTR(-EINVAL);
	400	}
02361418 ADK	401	cpufreq_dev->cool_dev = cool_dev;
	402	cpufreq_dev->cpufreq_state = 0;
	403	mutex_lock(&cooling_cpufreq_lock);
	404	list_add_tail(&cpufreq_dev->node, &cooling_cpufreq_list);
	405
	406	/* Register the notifier for first cpufreq cooling device */
	407	if (cpufreq_dev_count == 0)
	408	cpufreq_register_notifier(&thermal_cpufreq_notifier_block,
	409	CPUFREQ_POLICY_NOTIFIER);
	410
	411	mutex_unlock(&cooling_cpufreq_lock);
	412	return cool_dev;
	413	}
	414	EXPORT_SYMBOL(cpufreq_cooling_register);
	415
	416	/**
	417	* cpufreq_cooling_unregister - function to remove cpufreq cooling device.
	418	* @cdev: thermal cooling device pointer.
	419	*/
	420	void cpufreq_cooling_unregister(struct thermal_cooling_device *cdev)
	421	{
	422	struct cpufreq_cooling_device *cpufreq_dev = NULL;
	423	unsigned int cpufreq_dev_count = 0;
	424
	425	mutex_lock(&cooling_cpufreq_lock);
	426	list_for_each_entry(cpufreq_dev, &cooling_cpufreq_list, node) {
	427	if (cpufreq_dev && cpufreq_dev->cool_dev == cdev)
	428	break;
	429	cpufreq_dev_count++;
	430	}
	431
	432	if (!cpufreq_dev \|\| cpufreq_dev->cool_dev != cdev) {
	433	mutex_unlock(&cooling_cpufreq_lock);
	434	return;
	435	}
	436
	437	list_del(&cpufreq_dev->node);
	438
	439	/* Unregister the notifier for the last cpufreq cooling device */
	440	if (cpufreq_dev_count == 1) {
	441	cpufreq_unregister_notifier(&thermal_cpufreq_notifier_block,
	442	CPUFREQ_POLICY_NOTIFIER);
	443	}
	444	mutex_unlock(&cooling_cpufreq_lock);
	445	thermal_cooling_device_unregister(cpufreq_dev->cool_dev);
	446	release_idr(&cpufreq_idr, cpufreq_dev->id);
	447	if (cpufreq_dev_count == 1)
	448	mutex_destroy(&cooling_cpufreq_lock);
	449	kfree(cpufreq_dev);
	450	}
	451	EXPORT_SYMBOL(cpufreq_cooling_unregister);