[deliverable/linux.git] / drivers / cpufreq / cpufreq_conservative.c

/*
 *  drivers/cpufreq/cpufreq_conservative.c
 *
 *  Copyright (C)  2001 Russell King
 *            (C)  2003 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>.
 *                      Jun Nakajima <jun.nakajima@intel.com>
 *            (C)  2009 Alexander Clouter <alex@digriz.org.uk>
 *
 * 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/slab.h>
#include "cpufreq_governor.h"

struct cs_policy_dbs_info {
	struct policy_dbs_info policy_dbs;
	unsigned int down_skip;
	unsigned int requested_freq;
};

static inline struct cs_policy_dbs_info *to_dbs_info(struct policy_dbs_info *policy_dbs)
{
	return container_of(policy_dbs, struct cs_policy_dbs_info, policy_dbs);
}

struct cs_dbs_tuners {
	unsigned int down_threshold;
	unsigned int freq_step;
};

/* Conservative governor macros */
#define DEF_FREQUENCY_UP_THRESHOLD		(80)
#define DEF_FREQUENCY_DOWN_THRESHOLD		(20)
#define DEF_FREQUENCY_STEP			(5)
#define DEF_SAMPLING_DOWN_FACTOR		(1)
#define MAX_SAMPLING_DOWN_FACTOR		(10)

static inline unsigned int get_freq_target(struct cs_dbs_tuners *cs_tuners,
					   struct cpufreq_policy *policy)
{
	unsigned int freq_target = (cs_tuners->freq_step * policy->max) / 100;

	/* max freq cannot be less than 100. But who knows... */
	if (unlikely(freq_target == 0))
		freq_target = DEF_FREQUENCY_STEP;

	return freq_target;
}

/*
 * Every sampling_rate, we check, if current idle time is less than 20%
 * (default), then we try to increase frequency. Every sampling_rate *
 * sampling_down_factor, we check, if current idle time is more than 80%
 * (default), then we try to decrease frequency
 *
 * Any frequency increase takes it to the maximum frequency. Frequency reduction
 * happens at minimum steps of 5% (default) of maximum frequency
 */
static unsigned int cs_dbs_timer(struct cpufreq_policy *policy)
{
	struct policy_dbs_info *policy_dbs = policy->governor_data;
	struct cs_policy_dbs_info *dbs_info = to_dbs_info(policy_dbs);
	struct dbs_data *dbs_data = policy_dbs->dbs_data;
	struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
	unsigned int load = dbs_update(policy);

	/*
	 * break out if we 'cannot' reduce the speed as the user might
	 * want freq_step to be zero
	 */
	if (cs_tuners->freq_step == 0)
		goto out;

	/* Check for frequency increase */
	if (load > dbs_data->up_threshold) {
		dbs_info->down_skip = 0;

		/* if we are already at full speed then break out early */
		if (dbs_info->requested_freq == policy->max)
			goto out;

		dbs_info->requested_freq += get_freq_target(cs_tuners, policy);

		if (dbs_info->requested_freq > policy->max)
			dbs_info->requested_freq = policy->max;

		__cpufreq_driver_target(policy, dbs_info->requested_freq,
			CPUFREQ_RELATION_H);
		goto out;
	}

	/* if sampling_down_factor is active break out early */
	if (++dbs_info->down_skip < dbs_data->sampling_down_factor)
		goto out;
	dbs_info->down_skip = 0;

	/* Check for frequency decrease */
	if (load < cs_tuners->down_threshold) {
		unsigned int freq_target;
		/*
		 * if we cannot reduce the frequency anymore, break out early
		 */
		if (policy->cur == policy->min)
			goto out;

		freq_target = get_freq_target(cs_tuners, policy);
		if (dbs_info->requested_freq > freq_target)
			dbs_info->requested_freq -= freq_target;
		else
			dbs_info->requested_freq = policy->min;

		__cpufreq_driver_target(policy, dbs_info->requested_freq,
				CPUFREQ_RELATION_L);
	}

 out:
	return dbs_data->sampling_rate;
}

static int dbs_cpufreq_notifier(struct notifier_block *nb, unsigned long val,
				void *data);

static struct notifier_block cs_cpufreq_notifier_block = {
	.notifier_call = dbs_cpufreq_notifier,
};

/************************** sysfs interface ************************/
static struct dbs_governor cs_dbs_gov;

static ssize_t store_sampling_down_factor(struct gov_attr_set *attr_set,
					  const char *buf, size_t count)
{
	struct dbs_data *dbs_data = to_dbs_data(attr_set);
	unsigned int input;
	int ret;
	ret = sscanf(buf, "%u", &input);

	if (ret != 1 || input > MAX_SAMPLING_DOWN_FACTOR || input < 1)
		return -EINVAL;

	dbs_data->sampling_down_factor = input;
	return count;
}

static ssize_t store_up_threshold(struct gov_attr_set *attr_set,
				  const char *buf, size_t count)
{
	struct dbs_data *dbs_data = to_dbs_data(attr_set);
	struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
	unsigned int input;
	int ret;
	ret = sscanf(buf, "%u", &input);

	if (ret != 1 || input > 100 || input <= cs_tuners->down_threshold)
		return -EINVAL;

	dbs_data->up_threshold = input;
	return count;
}

static ssize_t store_down_threshold(struct gov_attr_set *attr_set,
				    const char *buf, size_t count)
{
	struct dbs_data *dbs_data = to_dbs_data(attr_set);
	struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
	unsigned int input;
	int ret;
	ret = sscanf(buf, "%u", &input);

	/* cannot be lower than 11 otherwise freq will not fall */
	if (ret != 1 || input < 11 || input > 100 ||
			input >= dbs_data->up_threshold)
		return -EINVAL;

	cs_tuners->down_threshold = input;
	return count;
}

static ssize_t store_ignore_nice_load(struct gov_attr_set *attr_set,
				      const char *buf, size_t count)
{
	struct dbs_data *dbs_data = to_dbs_data(attr_set);
	unsigned int input;
	int ret;

	ret = sscanf(buf, "%u", &input);
	if (ret != 1)
		return -EINVAL;

	if (input > 1)
		input = 1;

	if (input == dbs_data->ignore_nice_load) /* nothing to do */
		return count;

	dbs_data->ignore_nice_load = input;

	/* we need to re-evaluate prev_cpu_idle */
	gov_update_cpu_data(dbs_data);

	return count;
}

static ssize_t store_freq_step(struct gov_attr_set *attr_set, const char *buf,
			       size_t count)
{
	struct dbs_data *dbs_data = to_dbs_data(attr_set);
	struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
	unsigned int input;
	int ret;
	ret = sscanf(buf, "%u", &input);

	if (ret != 1)
		return -EINVAL;

	if (input > 100)
		input = 100;

	/*
	 * no need to test here if freq_step is zero as the user might actually
	 * want this, they would be crazy though :)
	 */
	cs_tuners->freq_step = input;
	return count;
}

gov_show_one_common(sampling_rate);
gov_show_one_common(sampling_down_factor);
gov_show_one_common(up_threshold);
gov_show_one_common(ignore_nice_load);
gov_show_one_common(min_sampling_rate);
gov_show_one(cs, down_threshold);
gov_show_one(cs, freq_step);

gov_attr_rw(sampling_rate);
gov_attr_rw(sampling_down_factor);
gov_attr_rw(up_threshold);
gov_attr_rw(ignore_nice_load);
gov_attr_ro(min_sampling_rate);
gov_attr_rw(down_threshold);
gov_attr_rw(freq_step);

static struct attribute *cs_attributes[] = {
	&min_sampling_rate.attr,
	&sampling_rate.attr,
	&sampling_down_factor.attr,
	&up_threshold.attr,
	&down_threshold.attr,
	&ignore_nice_load.attr,
	&freq_step.attr,
	NULL
};

/************************** sysfs end ************************/

static struct policy_dbs_info *cs_alloc(void)
{
	struct cs_policy_dbs_info *dbs_info;

	dbs_info = kzalloc(sizeof(*dbs_info), GFP_KERNEL);
	return dbs_info ? &dbs_info->policy_dbs : NULL;
}

static void cs_free(struct policy_dbs_info *policy_dbs)
{
	kfree(to_dbs_info(policy_dbs));
}

static int cs_init(struct dbs_data *dbs_data, bool notify)
{
	struct cs_dbs_tuners *tuners;

	tuners = kzalloc(sizeof(*tuners), GFP_KERNEL);
	if (!tuners) {
		pr_err("%s: kzalloc failed\n", __func__);
		return -ENOMEM;
	}

	tuners->down_threshold = DEF_FREQUENCY_DOWN_THRESHOLD;
	tuners->freq_step = DEF_FREQUENCY_STEP;
	dbs_data->up_threshold = DEF_FREQUENCY_UP_THRESHOLD;
	dbs_data->sampling_down_factor = DEF_SAMPLING_DOWN_FACTOR;
	dbs_data->ignore_nice_load = 0;

	dbs_data->tuners = tuners;
	dbs_data->min_sampling_rate = MIN_SAMPLING_RATE_RATIO *
		jiffies_to_usecs(10);

	if (notify)
		cpufreq_register_notifier(&cs_cpufreq_notifier_block,
					  CPUFREQ_TRANSITION_NOTIFIER);

	return 0;
}

static void cs_exit(struct dbs_data *dbs_data, bool notify)
{
	if (notify)
		cpufreq_unregister_notifier(&cs_cpufreq_notifier_block,
					    CPUFREQ_TRANSITION_NOTIFIER);

	kfree(dbs_data->tuners);
}

static void cs_start(struct cpufreq_policy *policy)
{
	struct cs_policy_dbs_info *dbs_info = to_dbs_info(policy->governor_data);

	dbs_info->down_skip = 0;
	dbs_info->requested_freq = policy->cur;
}

static struct dbs_governor cs_dbs_gov = {
	.gov = {
		.name = "conservative",
		.governor = cpufreq_governor_dbs,
		.max_transition_latency = TRANSITION_LATENCY_LIMIT,
		.owner = THIS_MODULE,
	},
	.kobj_type = { .default_attrs = cs_attributes },
	.gov_dbs_timer = cs_dbs_timer,
	.alloc = cs_alloc,
	.free = cs_free,
	.init = cs_init,
	.exit = cs_exit,
	.start = cs_start,
};

#define CPU_FREQ_GOV_CONSERVATIVE	(&cs_dbs_gov.gov)

static int dbs_cpufreq_notifier(struct notifier_block *nb, unsigned long val,
				void *data)
{
	struct cpufreq_freqs *freq = data;
	struct cpufreq_policy *policy = cpufreq_cpu_get_raw(freq->cpu);
	struct cs_policy_dbs_info *dbs_info;

	if (!policy)
		return 0;

	/* policy isn't governed by conservative governor */
	if (policy->governor != CPU_FREQ_GOV_CONSERVATIVE)
		return 0;

	dbs_info = to_dbs_info(policy->governor_data);
	/*
	 * we only care if our internally tracked freq moves outside the 'valid'
	 * ranges of frequency available to us otherwise we do not change it
	*/
	if (dbs_info->requested_freq > policy->max
			|| dbs_info->requested_freq < policy->min)
		dbs_info->requested_freq = freq->new;

	return 0;
}

static int __init cpufreq_gov_dbs_init(void)
{
	return cpufreq_register_governor(CPU_FREQ_GOV_CONSERVATIVE);
}

static void __exit cpufreq_gov_dbs_exit(void)
{
	cpufreq_unregister_governor(CPU_FREQ_GOV_CONSERVATIVE);
}

MODULE_AUTHOR("Alexander Clouter <alex@digriz.org.uk>");
MODULE_DESCRIPTION("'cpufreq_conservative' - A dynamic cpufreq governor for "
		"Low Latency Frequency Transition capable processors "
		"optimised for use in a battery environment");
MODULE_LICENSE("GPL");

#ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_CONSERVATIVE
struct cpufreq_governor *cpufreq_default_governor(void)
{
	return CPU_FREQ_GOV_CONSERVATIVE;
}

fs_initcall(cpufreq_gov_dbs_init);
#else
module_init(cpufreq_gov_dbs_init);
#endif
module_exit(cpufreq_gov_dbs_exit);
Commit	Line	Data
b9170836 DJ	1	/*
	2	* drivers/cpufreq/cpufreq_conservative.c
	3	*
	4	* Copyright (C) 2001 Russell King
	5	* (C) 2003 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>.
	6	* Jun Nakajima <jun.nakajima@intel.com>
11a80a9c	7	* (C) 2009 Alexander Clouter <alex@digriz.org.uk>
b9170836 DJ	8	*
	9	* This program is free software; you can redistribute it and/or modify
	10	* it under the terms of the GNU General Public License version 2 as
	11	* published by the Free Software Foundation.
	12	*/
	13
4d5dcc42	14	#include <linux/slab.h>
4471a34f	15	#include "cpufreq_governor.h"
b9170836	16
7d5a9956 RW	17	struct cs_policy_dbs_info {
	18	struct policy_dbs_info policy_dbs;
	19	unsigned int down_skip;
	20	unsigned int requested_freq;
	21	};
	22
	23	static inline struct cs_policy_dbs_info to_dbs_info(struct policy_dbs_info policy_dbs)
	24	{
	25	return container_of(policy_dbs, struct cs_policy_dbs_info, policy_dbs);
	26	}
	27
47ebaac1 RW	28	struct cs_dbs_tuners {
	29	unsigned int down_threshold;
	30	unsigned int freq_step;
	31	};
	32
c88883cd	33	/* Conservative governor macros */
b9170836	34	#define DEF_FREQUENCY_UP_THRESHOLD (80)
b9170836	35	#define DEF_FREQUENCY_DOWN_THRESHOLD (20)
98765847	36	#define DEF_FREQUENCY_STEP (5)
2c906b31 AC	37	#define DEF_SAMPLING_DOWN_FACTOR (1)
2c906b31 AC	38	#define MAX_SAMPLING_DOWN_FACTOR (10)
b9170836	39
98765847 SK	40	static inline unsigned int get_freq_target(struct cs_dbs_tuners *cs_tuners,
	41	struct cpufreq_policy *policy)
	42	{
	43	unsigned int freq_target = (cs_tuners->freq_step * policy->max) / 100;
	44
	45	/* max freq cannot be less than 100. But who knows... */
	46	if (unlikely(freq_target == 0))
	47	freq_target = DEF_FREQUENCY_STEP;
	48
	49	return freq_target;
	50	}
	51
4471a34f VK	52	/*
4471a34f VK	53	* Every sampling_rate, we check, if current idle time is less than 20%
7af1c056 SK	54	* (default), then we try to increase frequency. Every sampling_rate *
	55	* sampling_down_factor, we check, if current idle time is more than 80%
	56	* (default), then we try to decrease frequency
4471a34f VK	57	*
	58	* Any frequency increase takes it to the maximum frequency. Frequency reduction
	59	* happens at minimum steps of 5% (default) of maximum frequency
	60	*/
4cccf755	61	static unsigned int cs_dbs_timer(struct cpufreq_policy *policy)
a8d7c3bc	62	{
bc505475	63	struct policy_dbs_info *policy_dbs = policy->governor_data;
7d5a9956	64	struct cs_policy_dbs_info *dbs_info = to_dbs_info(policy_dbs);
bc505475	65	struct dbs_data *dbs_data = policy_dbs->dbs_data;
4d5dcc42	66	struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
4cccf755	67	unsigned int load = dbs_update(policy);
4471a34f VK	68
	69	/*
	70	* break out if we 'cannot' reduce the speed as the user might
	71	* want freq_step to be zero
	72	*/
4d5dcc42	73	if (cs_tuners->freq_step == 0)
4cccf755	74	goto out;
4471a34f VK	75
4471a34f VK	76	/* Check for frequency increase */
ff4b1789	77	if (load > dbs_data->up_threshold) {
4471a34f VK	78	dbs_info->down_skip = 0;
	79
	80	/* if we are already at full speed then break out early */
	81	if (dbs_info->requested_freq == policy->max)
4cccf755	82	goto out;
4471a34f	83
98765847	84	dbs_info->requested_freq += get_freq_target(cs_tuners, policy);
a8d7c3bc	85
6d7bcb14 XC	86	if (dbs_info->requested_freq > policy->max)
	87	dbs_info->requested_freq = policy->max;
	88
4471a34f VK	89	__cpufreq_driver_target(policy, dbs_info->requested_freq,
4471a34f VK	90	CPUFREQ_RELATION_H);
4cccf755	91	goto out;
4471a34f VK	92	}
4471a34f VK	93
7af1c056	94	/* if sampling_down_factor is active break out early */
ff4b1789	95	if (++dbs_info->down_skip < dbs_data->sampling_down_factor)
4cccf755	96	goto out;
7af1c056 SK	97	dbs_info->down_skip = 0;
7af1c056 SK	98
27ed3cd2 SK	99	/* Check for frequency decrease */
27ed3cd2 SK	100	if (load < cs_tuners->down_threshold) {
3baa976a	101	unsigned int freq_target;
4471a34f VK	102	/*
	103	* if we cannot reduce the frequency anymore, break out early
	104	*/
	105	if (policy->cur == policy->min)
4cccf755	106	goto out;
4471a34f	107
3baa976a XC	108	freq_target = get_freq_target(cs_tuners, policy);
	109	if (dbs_info->requested_freq > freq_target)
	110	dbs_info->requested_freq -= freq_target;
	111	else
	112	dbs_info->requested_freq = policy->min;
ad529a9c	113
4471a34f	114	__cpufreq_driver_target(policy, dbs_info->requested_freq,
fed573d5	115	CPUFREQ_RELATION_L);
4471a34f	116	}
43e0ee36	117
4cccf755	118	out:
07aa4402	119	return dbs_data->sampling_rate;
66df2a01 FB	120	}
66df2a01 FB	121
4471a34f	122	static int dbs_cpufreq_notifier(struct notifier_block *nb, unsigned long val,
af926185	123	void *data);
a8d7c3bc	124
8e0484d2 VK	125	static struct notifier_block cs_cpufreq_notifier_block = {
	126	.notifier_call = dbs_cpufreq_notifier,
	127	};
	128
b9170836	129	/************************ sysfs interface **********************/
7bdad34d	130	static struct dbs_governor cs_dbs_gov;
b9170836	131
0dd3c1d6 RW	132	static ssize_t store_sampling_down_factor(struct gov_attr_set *attr_set,
0dd3c1d6 RW	133	const char *buf, size_t count)
b9170836	134	{
0dd3c1d6	135	struct dbs_data *dbs_data = to_dbs_data(attr_set);
b9170836 DJ	136	unsigned int input;
b9170836 DJ	137	int ret;
9acef487	138	ret = sscanf(buf, "%u", &input);
8e677ce8	139
2c906b31	140	if (ret != 1 \|\| input > MAX_SAMPLING_DOWN_FACTOR \|\| input < 1)
b9170836 DJ	141	return -EINVAL;
b9170836 DJ	142
ff4b1789	143	dbs_data->sampling_down_factor = input;
b9170836 DJ	144	return count;
	145	}
	146
0dd3c1d6 RW	147	static ssize_t store_up_threshold(struct gov_attr_set *attr_set,
0dd3c1d6 RW	148	const char *buf, size_t count)
b9170836	149	{
0dd3c1d6	150	struct dbs_data *dbs_data = to_dbs_data(attr_set);
4d5dcc42	151	struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
b9170836 DJ	152	unsigned int input;
b9170836 DJ	153	int ret;
9acef487	154	ret = sscanf(buf, "%u", &input);
b9170836	155
4d5dcc42	156	if (ret != 1 \|\| input > 100 \|\| input <= cs_tuners->down_threshold)
b9170836	157	return -EINVAL;
b9170836	158
ff4b1789	159	dbs_data->up_threshold = input;
b9170836 DJ	160	return count;
	161	}
	162
0dd3c1d6 RW	163	static ssize_t store_down_threshold(struct gov_attr_set *attr_set,
0dd3c1d6 RW	164	const char *buf, size_t count)
b9170836	165	{
0dd3c1d6	166	struct dbs_data *dbs_data = to_dbs_data(attr_set);
4d5dcc42	167	struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
b9170836 DJ	168	unsigned int input;
b9170836 DJ	169	int ret;
9acef487	170	ret = sscanf(buf, "%u", &input);
b9170836	171
8e677ce8 AC	172	/* cannot be lower than 11 otherwise freq will not fall */
8e677ce8 AC	173	if (ret != 1 \|\| input < 11 \|\| input > 100 \|\|
ff4b1789	174	input >= dbs_data->up_threshold)
b9170836	175	return -EINVAL;
b9170836	176
4d5dcc42	177	cs_tuners->down_threshold = input;
b9170836 DJ	178	return count;
	179	}
	180
0dd3c1d6 RW	181	static ssize_t store_ignore_nice_load(struct gov_attr_set *attr_set,
0dd3c1d6 RW	182	const char *buf, size_t count)
b9170836	183	{
0dd3c1d6	184	struct dbs_data *dbs_data = to_dbs_data(attr_set);
a33cce1c	185	unsigned int input;
b9170836 DJ	186	int ret;
b9170836 DJ	187
18a7247d DJ	188	ret = sscanf(buf, "%u", &input);
18a7247d DJ	189	if (ret != 1)
b9170836 DJ	190	return -EINVAL;
b9170836 DJ	191
18a7247d	192	if (input > 1)
b9170836	193	input = 1;
18a7247d	194
ff4b1789	195	if (input == dbs_data->ignore_nice_load) /* nothing to do */
b9170836	196	return count;
326c86de	197
ff4b1789	198	dbs_data->ignore_nice_load = input;
b9170836	199
8e677ce8	200	/* we need to re-evaluate prev_cpu_idle */
8c8f77fd	201	gov_update_cpu_data(dbs_data);
a33cce1c	202
b9170836 DJ	203	return count;
	204	}
	205
0dd3c1d6 RW	206	static ssize_t store_freq_step(struct gov_attr_set attr_set, const char buf,
0dd3c1d6 RW	207	size_t count)
b9170836	208	{
0dd3c1d6	209	struct dbs_data *dbs_data = to_dbs_data(attr_set);
4d5dcc42	210	struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
b9170836 DJ	211	unsigned int input;
b9170836 DJ	212	int ret;
18a7247d	213	ret = sscanf(buf, "%u", &input);
b9170836	214
18a7247d	215	if (ret != 1)
b9170836 DJ	216	return -EINVAL;
b9170836 DJ	217
18a7247d	218	if (input > 100)
b9170836	219	input = 100;
18a7247d	220
4471a34f VK	221	/*
	222	* no need to test here if freq_step is zero as the user might actually
	223	* want this, they would be crazy though :)
	224	*/
4d5dcc42	225	cs_tuners->freq_step = input;
b9170836 DJ	226	return count;
	227	}
	228
c4435630 VK	229	gov_show_one_common(sampling_rate);
	230	gov_show_one_common(sampling_down_factor);
	231	gov_show_one_common(up_threshold);
	232	gov_show_one_common(ignore_nice_load);
	233	gov_show_one_common(min_sampling_rate);
	234	gov_show_one(cs, down_threshold);
	235	gov_show_one(cs, freq_step);
	236
	237	gov_attr_rw(sampling_rate);
	238	gov_attr_rw(sampling_down_factor);
	239	gov_attr_rw(up_threshold);
	240	gov_attr_rw(ignore_nice_load);
	241	gov_attr_ro(min_sampling_rate);
	242	gov_attr_rw(down_threshold);
	243	gov_attr_rw(freq_step);
	244
	245	static struct attribute *cs_attributes[] = {
	246	&min_sampling_rate.attr,
	247	&sampling_rate.attr,
	248	&sampling_down_factor.attr,
	249	&up_threshold.attr,
	250	&down_threshold.attr,
	251	&ignore_nice_load.attr,
	252	&freq_step.attr,
b9170836 DJ	253	NULL
	254	};
	255
b9170836 DJ	256	/************************ sysfs end **********************/
b9170836 DJ	257
7d5a9956 RW	258	static struct policy_dbs_info *cs_alloc(void)
	259	{
	260	struct cs_policy_dbs_info *dbs_info;
	261
	262	dbs_info = kzalloc(sizeof(*dbs_info), GFP_KERNEL);
	263	return dbs_info ? &dbs_info->policy_dbs : NULL;
	264	}
	265
	266	static void cs_free(struct policy_dbs_info *policy_dbs)
	267	{
	268	kfree(to_dbs_info(policy_dbs));
	269	}
	270
8e0484d2	271	static int cs_init(struct dbs_data *dbs_data, bool notify)
4d5dcc42 VK	272	{
	273	struct cs_dbs_tuners *tuners;
	274
d5b73cd8	275	tuners = kzalloc(sizeof(*tuners), GFP_KERNEL);
4d5dcc42 VK	276	if (!tuners) {
	277	pr_err("%s: kzalloc failed\n", __func__);
	278	return -ENOMEM;
	279	}
	280
4d5dcc42	281	tuners->down_threshold = DEF_FREQUENCY_DOWN_THRESHOLD;
98765847	282	tuners->freq_step = DEF_FREQUENCY_STEP;
ff4b1789 VK	283	dbs_data->up_threshold = DEF_FREQUENCY_UP_THRESHOLD;
	284	dbs_data->sampling_down_factor = DEF_SAMPLING_DOWN_FACTOR;
	285	dbs_data->ignore_nice_load = 0;
4d5dcc42 VK	286
	287	dbs_data->tuners = tuners;
	288	dbs_data->min_sampling_rate = MIN_SAMPLING_RATE_RATIO *
	289	jiffies_to_usecs(10);
8e0484d2 VK	290
	291	if (notify)
	292	cpufreq_register_notifier(&cs_cpufreq_notifier_block,
	293	CPUFREQ_TRANSITION_NOTIFIER);
	294
4d5dcc42 VK	295	return 0;
	296	}
	297
8e0484d2	298	static void cs_exit(struct dbs_data *dbs_data, bool notify)
4d5dcc42	299	{
8e0484d2 VK	300	if (notify)
	301	cpufreq_unregister_notifier(&cs_cpufreq_notifier_block,
	302	CPUFREQ_TRANSITION_NOTIFIER);
	303
4d5dcc42 VK	304	kfree(dbs_data->tuners);
	305	}
	306
702c9e54 RW	307	static void cs_start(struct cpufreq_policy *policy)
702c9e54 RW	308	{
7d5a9956	309	struct cs_policy_dbs_info *dbs_info = to_dbs_info(policy->governor_data);
702c9e54 RW	310
	311	dbs_info->down_skip = 0;
	312	dbs_info->requested_freq = policy->cur;
	313	}
	314
7bdad34d	315	static struct dbs_governor cs_dbs_gov = {
af926185 RW	316	.gov = {
af926185 RW	317	.name = "conservative",
906a6e5a	318	.governor = cpufreq_governor_dbs,
af926185 RW	319	.max_transition_latency = TRANSITION_LATENCY_LIMIT,
	320	.owner = THIS_MODULE,
	321	},
c4435630	322	.kobj_type = { .default_attrs = cs_attributes },
4471a34f	323	.gov_dbs_timer = cs_dbs_timer,
7d5a9956 RW	324	.alloc = cs_alloc,
7d5a9956 RW	325	.free = cs_free,
4d5dcc42 VK	326	.init = cs_init,
4d5dcc42 VK	327	.exit = cs_exit,
702c9e54	328	.start = cs_start,
4471a34f	329	};
b9170836	330
7bdad34d	331	#define CPU_FREQ_GOV_CONSERVATIVE (&cs_dbs_gov.gov)
af926185	332
af926185 RW	333	static int dbs_cpufreq_notifier(struct notifier_block *nb, unsigned long val,
	334	void *data)
	335	{
	336	struct cpufreq_freqs *freq = data;
af926185	337	struct cpufreq_policy *policy = cpufreq_cpu_get_raw(freq->cpu);
7d5a9956	338	struct cs_policy_dbs_info *dbs_info;
af926185 RW	339
	340	if (!policy)
	341	return 0;
	342
	343	/* policy isn't governed by conservative governor */
	344	if (policy->governor != CPU_FREQ_GOV_CONSERVATIVE)
	345	return 0;
	346
7d5a9956	347	dbs_info = to_dbs_info(policy->governor_data);
af926185 RW	348	/*
	349	* we only care if our internally tracked freq moves outside the 'valid'
	350	* ranges of frequency available to us otherwise we do not change it
	351	*/
	352	if (dbs_info->requested_freq > policy->max
	353	\|\| dbs_info->requested_freq < policy->min)
	354	dbs_info->requested_freq = freq->new;
	355
	356	return 0;
	357	}
	358
b9170836 DJ	359	static int __init cpufreq_gov_dbs_init(void)
b9170836 DJ	360	{
af926185	361	return cpufreq_register_governor(CPU_FREQ_GOV_CONSERVATIVE);
b9170836 DJ	362	}
	363
	364	static void __exit cpufreq_gov_dbs_exit(void)
	365	{
af926185	366	cpufreq_unregister_governor(CPU_FREQ_GOV_CONSERVATIVE);
b9170836 DJ	367	}
b9170836 DJ	368
11a80a9c	369	MODULE_AUTHOR("Alexander Clouter <alex@digriz.org.uk>");
9acef487	370	MODULE_DESCRIPTION("'cpufreq_conservative' - A dynamic cpufreq governor for "
b9170836 DJ	371	"Low Latency Frequency Transition capable processors "
b9170836 DJ	372	"optimised for use in a battery environment");
9acef487	373	MODULE_LICENSE("GPL");
b9170836	374
6915719b	375	#ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_CONSERVATIVE
de1df26b RW	376	struct cpufreq_governor *cpufreq_default_governor(void)
de1df26b RW	377	{
af926185	378	return CPU_FREQ_GOV_CONSERVATIVE;
de1df26b RW	379	}
de1df26b RW	380
6915719b JW	381	fs_initcall(cpufreq_gov_dbs_init);
6915719b JW	382	#else
b9170836	383	module_init(cpufreq_gov_dbs_init);
6915719b	384	#endif
b9170836	385	module_exit(cpufreq_gov_dbs_exit);