[linux-2.6-block.git] / drivers / cpufreq / cpufreq_stats.c

/*
 *  drivers/cpufreq/cpufreq_stats.c
 *
 *  Copyright (C) 2003-2004 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>.
 *  (C) 2004 Zou Nan hai <nanhai.zou@intel.com>.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/cpu.h>
#include <linux/cpufreq.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/cputime.h>

static spinlock_t cpufreq_stats_lock;

struct cpufreq_stats {
	unsigned int total_trans;
	unsigned long long last_time;
	unsigned int max_state;
	unsigned int state_num;
	unsigned int last_index;
	u64 *time_in_state;
	unsigned int *freq_table;
#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
	unsigned int *trans_table;
#endif
};

static int cpufreq_stats_update(struct cpufreq_stats *stats)
{
	unsigned long long cur_time = get_jiffies_64();

	spin_lock(&cpufreq_stats_lock);
	stats->time_in_state[stats->last_index] += cur_time - stats->last_time;
	stats->last_time = cur_time;
	spin_unlock(&cpufreq_stats_lock);
	return 0;
}

static ssize_t show_total_trans(struct cpufreq_policy *policy, char *buf)
{
	return sprintf(buf, "%d\n", policy->stats->total_trans);
}

static ssize_t show_time_in_state(struct cpufreq_policy *policy, char *buf)
{
	struct cpufreq_stats *stats = policy->stats;
	ssize_t len = 0;
	int i;

	cpufreq_stats_update(stats);
	for (i = 0; i < stats->state_num; i++) {
		len += sprintf(buf + len, "%u %llu\n", stats->freq_table[i],
			(unsigned long long)
			jiffies_64_to_clock_t(stats->time_in_state[i]));
	}
	return len;
}

#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
static ssize_t show_trans_table(struct cpufreq_policy *policy, char *buf)
{
	struct cpufreq_stats *stats = policy->stats;
	ssize_t len = 0;
	int i, j;

	len += snprintf(buf + len, PAGE_SIZE - len, "   From  :    To\n");
	len += snprintf(buf + len, PAGE_SIZE - len, "         : ");
	for (i = 0; i < stats->state_num; i++) {
		if (len >= PAGE_SIZE)
			break;
		len += snprintf(buf + len, PAGE_SIZE - len, "%9u ",
				stats->freq_table[i]);
	}
	if (len >= PAGE_SIZE)
		return PAGE_SIZE;

	len += snprintf(buf + len, PAGE_SIZE - len, "\n");

	for (i = 0; i < stats->state_num; i++) {
		if (len >= PAGE_SIZE)
			break;

		len += snprintf(buf + len, PAGE_SIZE - len, "%9u: ",
				stats->freq_table[i]);

		for (j = 0; j < stats->state_num; j++) {
			if (len >= PAGE_SIZE)
				break;
			len += snprintf(buf + len, PAGE_SIZE - len, "%9u ",
					stats->trans_table[i*stats->max_state+j]);
		}
		if (len >= PAGE_SIZE)
			break;
		len += snprintf(buf + len, PAGE_SIZE - len, "\n");
	}
	if (len >= PAGE_SIZE)
		return PAGE_SIZE;
	return len;
}
cpufreq_freq_attr_ro(trans_table);
#endif

cpufreq_freq_attr_ro(total_trans);
cpufreq_freq_attr_ro(time_in_state);

static struct attribute *default_attrs[] = {
	&total_trans.attr,
	&time_in_state.attr,
#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
	&trans_table.attr,
#endif
	NULL
};
static struct attribute_group stats_attr_group = {
	.attrs = default_attrs,
	.name = "stats"
};

static int freq_table_get_index(struct cpufreq_stats *stats, unsigned int freq)
{
	int index;
	for (index = 0; index < stats->max_state; index++)
		if (stats->freq_table[index] == freq)
			return index;
	return -1;
}

static void __cpufreq_stats_free_table(struct cpufreq_policy *policy)
{
	struct cpufreq_stats *stats = policy->stats;

	/* Already freed */
	if (!stats)
		return;

	pr_debug("%s: Free stats table\n", __func__);

	sysfs_remove_group(&policy->kobj, &stats_attr_group);
	kfree(stats->time_in_state);
	kfree(stats);
	policy->stats = NULL;
}

static void cpufreq_stats_free_table(unsigned int cpu)
{
	struct cpufreq_policy *policy;

	policy = cpufreq_cpu_get(cpu);
	if (!policy)
		return;

	__cpufreq_stats_free_table(policy);

	cpufreq_cpu_put(policy);
}

static int __cpufreq_stats_create_table(struct cpufreq_policy *policy)
{
	unsigned int i = 0, count = 0, ret = -ENOMEM;
	struct cpufreq_stats *stats;
	unsigned int alloc_size;
	unsigned int cpu = policy->cpu;
	struct cpufreq_frequency_table *pos, *table;

	/* We need cpufreq table for creating stats table */
	table = cpufreq_frequency_get_table(cpu);
	if (unlikely(!table))
		return 0;

	/* stats already initialized */
	if (policy->stats)
		return -EEXIST;

	stats = kzalloc(sizeof(*stats), GFP_KERNEL);
	if (!stats)
		return -ENOMEM;

	/* Find total allocation size */
	cpufreq_for_each_valid_entry(pos, table)
		count++;

	alloc_size = count * sizeof(int) + count * sizeof(u64);

#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
	alloc_size += count * count * sizeof(int);
#endif

	/* Allocate memory for time_in_state/freq_table/trans_table in one go */
	stats->time_in_state = kzalloc(alloc_size, GFP_KERNEL);
	if (!stats->time_in_state)
		goto free_stat;

	stats->freq_table = (unsigned int *)(stats->time_in_state + count);

#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
	stats->trans_table = stats->freq_table + count;
#endif

	stats->max_state = count;

	/* Find valid-unique entries */
	cpufreq_for_each_valid_entry(pos, table)
		if (freq_table_get_index(stats, pos->frequency) == -1)
			stats->freq_table[i++] = pos->frequency;

	stats->state_num = i;
	stats->last_time = get_jiffies_64();
	stats->last_index = freq_table_get_index(stats, policy->cur);

	policy->stats = stats;
	ret = sysfs_create_group(&policy->kobj, &stats_attr_group);
	if (!ret)
		return 0;

	/* We failed, release resources */
	policy->stats = NULL;
	kfree(stats->time_in_state);
free_stat:
	kfree(stats);

	return ret;
}

static void cpufreq_stats_create_table(unsigned int cpu)
{
	struct cpufreq_policy *policy;

	/*
	 * "likely(!policy)" because normally cpufreq_stats will be registered
	 * before cpufreq driver
	 */
	policy = cpufreq_cpu_get(cpu);
	if (likely(!policy))
		return;

	__cpufreq_stats_create_table(policy);

	cpufreq_cpu_put(policy);
}

static int cpufreq_stat_notifier_policy(struct notifier_block *nb,
		unsigned long val, void *data)
{
	int ret = 0;
	struct cpufreq_policy *policy = data;

	if (val == CPUFREQ_CREATE_POLICY)
		ret = __cpufreq_stats_create_table(policy);
	else if (val == CPUFREQ_REMOVE_POLICY)
		__cpufreq_stats_free_table(policy);

	return ret;
}

static int cpufreq_stat_notifier_trans(struct notifier_block *nb,
		unsigned long val, void *data)
{
	struct cpufreq_freqs *freq = data;
	struct cpufreq_policy *policy = cpufreq_cpu_get(freq->cpu);
	struct cpufreq_stats *stats;
	int old_index, new_index;

	if (!policy) {
		pr_err("%s: No policy found\n", __func__);
		return 0;
	}

	if (val != CPUFREQ_POSTCHANGE)
		goto put_policy;

	if (!policy->stats) {
		pr_debug("%s: No stats found\n", __func__);
		goto put_policy;
	}

	stats = policy->stats;

	old_index = stats->last_index;
	new_index = freq_table_get_index(stats, freq->new);

	/* We can't do stats->time_in_state[-1]= .. */
	if (old_index == -1 || new_index == -1)
		goto put_policy;

	if (old_index == new_index)
		goto put_policy;

	cpufreq_stats_update(stats);

	stats->last_index = new_index;
#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
	stats->trans_table[old_index * stats->max_state + new_index]++;
#endif
	stats->total_trans++;

put_policy:
	cpufreq_cpu_put(policy);
	return 0;
}

static struct notifier_block notifier_policy_block = {
	.notifier_call = cpufreq_stat_notifier_policy
};

static struct notifier_block notifier_trans_block = {
	.notifier_call = cpufreq_stat_notifier_trans
};

static int __init cpufreq_stats_init(void)
{
	int ret;
	unsigned int cpu;

	spin_lock_init(&cpufreq_stats_lock);
	ret = cpufreq_register_notifier(&notifier_policy_block,
				CPUFREQ_POLICY_NOTIFIER);
	if (ret)
		return ret;

	for_each_online_cpu(cpu)
		cpufreq_stats_create_table(cpu);

	ret = cpufreq_register_notifier(&notifier_trans_block,
				CPUFREQ_TRANSITION_NOTIFIER);
	if (ret) {
		cpufreq_unregister_notifier(&notifier_policy_block,
				CPUFREQ_POLICY_NOTIFIER);
		for_each_online_cpu(cpu)
			cpufreq_stats_free_table(cpu);
		return ret;
	}

	return 0;
}
static void __exit cpufreq_stats_exit(void)
{
	unsigned int cpu;

	cpufreq_unregister_notifier(&notifier_policy_block,
			CPUFREQ_POLICY_NOTIFIER);
	cpufreq_unregister_notifier(&notifier_trans_block,
			CPUFREQ_TRANSITION_NOTIFIER);
	for_each_online_cpu(cpu)
		cpufreq_stats_free_table(cpu);
}

MODULE_AUTHOR("Zou Nan hai <nanhai.zou@intel.com>");
MODULE_DESCRIPTION("Export cpufreq stats via sysfs");
MODULE_LICENSE("GPL");

module_init(cpufreq_stats_init);
module_exit(cpufreq_stats_exit);
Commit	Line	Data
1da177e4 LT	1	/*
	2	* drivers/cpufreq/cpufreq_stats.c
	3	*
	4	* Copyright (C) 2003-2004 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>.
0a829c5a	5	* (C) 2004 Zou Nan hai <nanhai.zou@intel.com>.
1da177e4 LT	6	*
	7	* This program is free software; you can redistribute it and/or modify
	8	* it under the terms of the GNU General Public License version 2 as
	9	* published by the Free Software Foundation.
	10	*/
	11
1da177e4	12	#include <linux/cpu.h>
1da177e4	13	#include <linux/cpufreq.h>
5c720d37	14	#include <linux/module.h>
5ff0a268	15	#include <linux/slab.h>
bfc3f028	16	#include <linux/cputime.h>
1da177e4 LT	17
	18	static spinlock_t cpufreq_stats_lock;
	19
1da177e4	20	struct cpufreq_stats {
1da177e4	21	unsigned int total_trans;
bb176f7d	22	unsigned long long last_time;
1da177e4 LT	23	unsigned int max_state;
	24	unsigned int state_num;
	25	unsigned int last_index;
1e7586a1	26	u64 *time_in_state;
1da177e4 LT	27	unsigned int *freq_table;
	28	#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
	29	unsigned int *trans_table;
	30	#endif
	31	};
	32
50941607	33	static int cpufreq_stats_update(struct cpufreq_stats *stats)
1da177e4	34	{
9531347c	35	unsigned long long cur_time = get_jiffies_64();
58f1df25	36
1da177e4	37	spin_lock(&cpufreq_stats_lock);
c960f9b2	38	stats->time_in_state[stats->last_index] += cur_time - stats->last_time;
50941607	39	stats->last_time = cur_time;
1da177e4 LT	40	spin_unlock(&cpufreq_stats_lock);
	41	return 0;
	42	}
	43
0a829c5a	44	static ssize_t show_total_trans(struct cpufreq_policy policy, char buf)
1da177e4	45	{
a9aaf291	46	return sprintf(buf, "%d\n", policy->stats->total_trans);
1da177e4 LT	47	}
1da177e4 LT	48
0a829c5a	49	static ssize_t show_time_in_state(struct cpufreq_policy policy, char buf)
1da177e4	50	{
50941607	51	struct cpufreq_stats *stats = policy->stats;
1da177e4 LT	52	ssize_t len = 0;
1da177e4 LT	53	int i;
a9aaf291	54
50941607 VK	55	cpufreq_stats_update(stats);
	56	for (i = 0; i < stats->state_num; i++) {
	57	len += sprintf(buf + len, "%u %llu\n", stats->freq_table[i],
0a829c5a	58	(unsigned long long)
50941607	59	jiffies_64_to_clock_t(stats->time_in_state[i]));
1da177e4 LT	60	}
	61	return len;
	62	}
	63
	64	#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
0a829c5a	65	static ssize_t show_trans_table(struct cpufreq_policy policy, char buf)
1da177e4	66	{
50941607	67	struct cpufreq_stats *stats = policy->stats;
1da177e4 LT	68	ssize_t len = 0;
	69	int i, j;
	70
58f1df25 VP	71	len += snprintf(buf + len, PAGE_SIZE - len, " From : To\n");
58f1df25 VP	72	len += snprintf(buf + len, PAGE_SIZE - len, " : ");
50941607	73	for (i = 0; i < stats->state_num; i++) {
58f1df25 VP	74	if (len >= PAGE_SIZE)
	75	break;
	76	len += snprintf(buf + len, PAGE_SIZE - len, "%9u ",
50941607	77	stats->freq_table[i]);
58f1df25 VP	78	}
58f1df25 VP	79	if (len >= PAGE_SIZE)
25aca347	80	return PAGE_SIZE;
58f1df25 VP	81
	82	len += snprintf(buf + len, PAGE_SIZE - len, "\n");
	83
50941607	84	for (i = 0; i < stats->state_num; i++) {
1da177e4 LT	85	if (len >= PAGE_SIZE)
1da177e4 LT	86	break;
58f1df25 VP	87
58f1df25 VP	88	len += snprintf(buf + len, PAGE_SIZE - len, "%9u: ",
50941607	89	stats->freq_table[i]);
1da177e4	90
50941607	91	for (j = 0; j < stats->state_num; j++) {
1da177e4 LT	92	if (len >= PAGE_SIZE)
1da177e4 LT	93	break;
58f1df25	94	len += snprintf(buf + len, PAGE_SIZE - len, "%9u ",
50941607	95	stats->trans_table[i*stats->max_state+j]);
1da177e4	96	}
25aca347 CEB	97	if (len >= PAGE_SIZE)
25aca347 CEB	98	break;
1da177e4 LT	99	len += snprintf(buf + len, PAGE_SIZE - len, "\n");
1da177e4 LT	100	}
25aca347 CEB	101	if (len >= PAGE_SIZE)
25aca347 CEB	102	return PAGE_SIZE;
1da177e4 LT	103	return len;
1da177e4 LT	104	}
df18e504	105	cpufreq_freq_attr_ro(trans_table);
1da177e4 LT	106	#endif
1da177e4 LT	107
df18e504 VK	108	cpufreq_freq_attr_ro(total_trans);
df18e504 VK	109	cpufreq_freq_attr_ro(time_in_state);
1da177e4 LT	110
1da177e4 LT	111	static struct attribute *default_attrs[] = {
df18e504 VK	112	&total_trans.attr,
df18e504 VK	113	&time_in_state.attr,
1da177e4	114	#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
df18e504	115	&trans_table.attr,
1da177e4 LT	116	#endif
	117	NULL
	118	};
	119	static struct attribute_group stats_attr_group = {
	120	.attrs = default_attrs,
	121	.name = "stats"
	122	};
	123
50941607	124	static int freq_table_get_index(struct cpufreq_stats *stats, unsigned int freq)
1da177e4 LT	125	{
1da177e4 LT	126	int index;
50941607 VK	127	for (index = 0; index < stats->max_state; index++)
50941607 VK	128	if (stats->freq_table[index] == freq)
1da177e4 LT	129	return index;
	130	return -1;
	131	}
	132
2d13594d	133	static void __cpufreq_stats_free_table(struct cpufreq_policy *policy)
1da177e4	134	{
50941607	135	struct cpufreq_stats *stats = policy->stats;
b8eed8af	136
a9aaf291	137	/* Already freed */
50941607	138	if (!stats)
2d13594d VK	139	return;
2d13594d VK	140
50941607	141	pr_debug("%s: Free stats table\n", __func__);
2d13594d VK	142
2d13594d VK	143	sysfs_remove_group(&policy->kobj, &stats_attr_group);
50941607 VK	144	kfree(stats->time_in_state);
50941607 VK	145	kfree(stats);
a9aaf291	146	policy->stats = NULL;
98586ed8	147	}
98586ed8	148
2d13594d	149	static void cpufreq_stats_free_table(unsigned int cpu)
98586ed8	150	{
2d13594d	151	struct cpufreq_policy *policy;
633d47d6	152
2d13594d	153	policy = cpufreq_cpu_get(cpu);
187da1d9	154	if (!policy)
633d47d6 DB	155	return;
633d47d6 DB	156
f93dbbbd	157	__cpufreq_stats_free_table(policy);
187da1d9	158
187da1d9	159	cpufreq_cpu_put(policy);
1da177e4 LT	160	}
1da177e4 LT	161
ad4c2302	162	static int __cpufreq_stats_create_table(struct cpufreq_policy *policy)
1da177e4	163	{
a685c6d0	164	unsigned int i = 0, count = 0, ret = -ENOMEM;
50941607	165	struct cpufreq_stats *stats;
1da177e4 LT	166	unsigned int alloc_size;
1da177e4 LT	167	unsigned int cpu = policy->cpu;
041526f9	168	struct cpufreq_frequency_table pos, table;
ad4c2302	169
a685c6d0	170	/* We need cpufreq table for creating stats table */
ad4c2302 SK	171	table = cpufreq_frequency_get_table(cpu);
	172	if (unlikely(!table))
	173	return 0;
	174
b8c67448	175	/* stats already initialized */
a9aaf291	176	if (policy->stats)
b8c67448 VK	177	return -EEXIST;
b8c67448 VK	178
50941607	179	stats = kzalloc(sizeof(*stats), GFP_KERNEL);
a685c6d0	180	if (!stats)
1da177e4	181	return -ENOMEM;
1da177e4	182
a685c6d0	183	/* Find total allocation size */
041526f9	184	cpufreq_for_each_valid_entry(pos, table)
1da177e4	185	count++;
1da177e4	186
1e7586a1	187	alloc_size = count * sizeof(int) + count * sizeof(u64);
1da177e4 LT	188
	189	#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
	190	alloc_size += count * count * sizeof(int);
	191	#endif
a685c6d0 VK	192
a685c6d0 VK	193	/* Allocate memory for time_in_state/freq_table/trans_table in one go */
50941607	194	stats->time_in_state = kzalloc(alloc_size, GFP_KERNEL);
a685c6d0 VK	195	if (!stats->time_in_state)
	196	goto free_stat;
	197
50941607	198	stats->freq_table = (unsigned int *)(stats->time_in_state + count);
1da177e4 LT	199
1da177e4 LT	200	#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
50941607	201	stats->trans_table = stats->freq_table + count;
1da177e4	202	#endif
a685c6d0 VK	203
	204	stats->max_state = count;
	205
	206	/* Find valid-unique entries */
041526f9	207	cpufreq_for_each_valid_entry(pos, table)
50941607 VK	208	if (freq_table_get_index(stats, pos->frequency) == -1)
50941607 VK	209	stats->freq_table[i++] = pos->frequency;
a685c6d0	210
490285c6	211	stats->state_num = i;
50941607 VK	212	stats->last_time = get_jiffies_64();
50941607 VK	213	stats->last_index = freq_table_get_index(stats, policy->cur);
a685c6d0 VK	214
	215	policy->stats = stats;
	216	ret = sysfs_create_group(&policy->kobj, &stats_attr_group);
	217	if (!ret)
	218	return 0;
	219
	220	/* We failed, release resources */
a9aaf291	221	policy->stats = NULL;
a685c6d0 VK	222	kfree(stats->time_in_state);
	223	free_stat:
	224	kfree(stats);
	225
1da177e4 LT	226	return ret;
	227	}
	228
b3f9ff88 VK	229	static void cpufreq_stats_create_table(unsigned int cpu)
	230	{
	231	struct cpufreq_policy *policy;
b3f9ff88 VK	232
	233	/*
	234	* "likely(!policy)" because normally cpufreq_stats will be registered
	235	* before cpufreq driver
	236	*/
	237	policy = cpufreq_cpu_get(cpu);
	238	if (likely(!policy))
	239	return;
	240
ad4c2302	241	__cpufreq_stats_create_table(policy);
b3f9ff88 VK	242
	243	cpufreq_cpu_put(policy);
	244	}
	245
0a829c5a DJ	246	static int cpufreq_stat_notifier_policy(struct notifier_block *nb,
0a829c5a DJ	247	unsigned long val, void *data)
1da177e4	248	{
fcd7af91	249	int ret = 0;
1da177e4	250	struct cpufreq_policy *policy = data;
b8eed8af	251
fcd7af91	252	if (val == CPUFREQ_CREATE_POLICY)
ad4c2302	253	ret = __cpufreq_stats_create_table(policy);
2d13594d VK	254	else if (val == CPUFREQ_REMOVE_POLICY)
2d13594d VK	255	__cpufreq_stats_free_table(policy);
fcd7af91 VK	256
fcd7af91 VK	257	return ret;
1da177e4 LT	258	}
1da177e4 LT	259
0a829c5a DJ	260	static int cpufreq_stat_notifier_trans(struct notifier_block *nb,
0a829c5a DJ	261	unsigned long val, void *data)
1da177e4 LT	262	{
1da177e4 LT	263	struct cpufreq_freqs *freq = data;
a9aaf291	264	struct cpufreq_policy *policy = cpufreq_cpu_get(freq->cpu);
50941607	265	struct cpufreq_stats *stats;
1da177e4 LT	266	int old_index, new_index;
1da177e4 LT	267
a9aaf291 VK	268	if (!policy) {
a9aaf291 VK	269	pr_err("%s: No policy found\n", __func__);
1da177e4	270	return 0;
a9aaf291	271	}
1da177e4	272
a9aaf291 VK	273	if (val != CPUFREQ_POSTCHANGE)
	274	goto put_policy;
	275
	276	if (!policy->stats) {
	277	pr_debug("%s: No stats found\n", __func__);
	278	goto put_policy;
	279	}
	280
50941607	281	stats = policy->stats;
8edc59d9	282
50941607 VK	283	old_index = stats->last_index;
50941607 VK	284	new_index = freq_table_get_index(stats, freq->new);
1da177e4	285
50941607	286	/* We can't do stats->time_in_state[-1]= .. */
46a310b8	287	if (old_index == -1 \|\| new_index == -1)
a9aaf291	288	goto put_policy;
1da177e4	289
46a310b8	290	if (old_index == new_index)
a9aaf291	291	goto put_policy;
8edc59d9	292
e7347694 VK	293	cpufreq_stats_update(stats);
e7347694 VK	294
50941607	295	stats->last_index = new_index;
1da177e4	296	#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
50941607	297	stats->trans_table[old_index * stats->max_state + new_index]++;
1da177e4	298	#endif
50941607	299	stats->total_trans++;
a9aaf291 VK	300
	301	put_policy:
	302	cpufreq_cpu_put(policy);
1da177e4 LT	303	return 0;
	304	}
	305
	306	static struct notifier_block notifier_policy_block = {
	307	.notifier_call = cpufreq_stat_notifier_policy
	308	};
	309
	310	static struct notifier_block notifier_trans_block = {
	311	.notifier_call = cpufreq_stat_notifier_trans
	312	};
	313
0a829c5a	314	static int __init cpufreq_stats_init(void)
1da177e4 LT	315	{
	316	int ret;
	317	unsigned int cpu;
c32b6b8e	318
1da177e4	319	spin_lock_init(&cpufreq_stats_lock);
0a829c5a DJ	320	ret = cpufreq_register_notifier(&notifier_policy_block,
	321	CPUFREQ_POLICY_NOTIFIER);
	322	if (ret)
1da177e4 LT	323	return ret;
1da177e4 LT	324
b3f9ff88 VK	325	for_each_online_cpu(cpu)
	326	cpufreq_stats_create_table(cpu);
	327
0a829c5a DJ	328	ret = cpufreq_register_notifier(&notifier_trans_block,
	329	CPUFREQ_TRANSITION_NOTIFIER);
	330	if (ret) {
1da177e4 LT	331	cpufreq_unregister_notifier(&notifier_policy_block,
1da177e4 LT	332	CPUFREQ_POLICY_NOTIFIER);
56836fb4 KK	333	for_each_online_cpu(cpu)
56836fb4 KK	334	cpufreq_stats_free_table(cpu);
1da177e4 LT	335	return ret;
	336	}
	337
1da177e4 LT	338	return 0;
1da177e4 LT	339	}
0a829c5a	340	static void __exit cpufreq_stats_exit(void)
1da177e4 LT	341	{
1da177e4 LT	342	unsigned int cpu;
c32b6b8e	343
1da177e4 LT	344	cpufreq_unregister_notifier(&notifier_policy_block,
	345	CPUFREQ_POLICY_NOTIFIER);
	346	cpufreq_unregister_notifier(&notifier_trans_block,
	347	CPUFREQ_TRANSITION_NOTIFIER);
2d13594d	348	for_each_online_cpu(cpu)
55395ae7	349	cpufreq_stats_free_table(cpu);
1da177e4 LT	350	}
1da177e4 LT	351
0a829c5a	352	MODULE_AUTHOR("Zou Nan hai <nanhai.zou@intel.com>");
00d0b294	353	MODULE_DESCRIPTION("Export cpufreq stats via sysfs");
0a829c5a	354	MODULE_LICENSE("GPL");
1da177e4 LT	355
	356	module_init(cpufreq_stats_init);
	357	module_exit(cpufreq_stats_exit);