[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"

/* 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 DEFINE_PER_CPU(struct cs_cpu_dbs_info_s, cs_cpu_dbs_info);

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 cs_cpu_dbs_info_s *dbs_info = &per_cpu(cs_cpu_dbs_info, policy->cpu);
	struct policy_dbs_info *policy_dbs = policy->governor_data;
	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 dbs_data *dbs_data,
		const char *buf, size_t count)
{
	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 dbs_data *dbs_data, const char *buf,
		size_t count)
{
	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 dbs_data *dbs_data, const char *buf,
		size_t count)
{
	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 dbs_data *dbs_data,
		const char *buf, size_t count)
{
	unsigned int input, j;
	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 */
	for_each_online_cpu(j) {
		struct cs_cpu_dbs_info_s *dbs_info;
		dbs_info = &per_cpu(cs_cpu_dbs_info, j);
		dbs_info->cdbs.prev_cpu_idle = get_cpu_idle_time(j,
					&dbs_info->cdbs.prev_cpu_wall, 0);
		if (dbs_data->ignore_nice_load)
			dbs_info->cdbs.prev_cpu_nice =
				kcpustat_cpu(j).cpustat[CPUTIME_NICE];
	}
	return count;
}

static ssize_t store_freq_step(struct dbs_data *dbs_data, const char *buf,
		size_t count)
{
	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 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);
}

define_get_cpu_dbs_routines(cs_cpu_dbs_info);

static struct dbs_governor cs_dbs_gov = {
	.gov = {
		.name = "conservative",
		.governor = cpufreq_governor_dbs,
		.max_transition_latency = TRANSITION_LATENCY_LIMIT,
		.owner = THIS_MODULE,
	},
	.governor = GOV_CONSERVATIVE,
	.kobj_type = { .default_attrs = cs_attributes },
	.get_cpu_cdbs = get_cpu_cdbs,
	.get_cpu_dbs_info_s = get_cpu_dbs_info_s,
	.gov_dbs_timer = cs_dbs_timer,
	.init = cs_init,
	.exit = cs_exit,
};

#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 cs_cpu_dbs_info_s *dbs_info =
					&per_cpu(cs_cpu_dbs_info, freq->cpu);
	struct cpufreq_policy *policy = cpufreq_cpu_get_raw(freq->cpu);

	if (!policy)
		return 0;

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

	/*
	 * 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
c88883cd	17	/* Conservative governor macros */
b9170836	18	#define DEF_FREQUENCY_UP_THRESHOLD (80)
b9170836	19	#define DEF_FREQUENCY_DOWN_THRESHOLD (20)
98765847	20	#define DEF_FREQUENCY_STEP (5)
2c906b31 AC	21	#define DEF_SAMPLING_DOWN_FACTOR (1)
2c906b31 AC	22	#define MAX_SAMPLING_DOWN_FACTOR (10)
b9170836	23
4471a34f	24	static DEFINE_PER_CPU(struct cs_cpu_dbs_info_s, cs_cpu_dbs_info);
b9170836	25
98765847 SK	26	static inline unsigned int get_freq_target(struct cs_dbs_tuners *cs_tuners,
	27	struct cpufreq_policy *policy)
	28	{
	29	unsigned int freq_target = (cs_tuners->freq_step * policy->max) / 100;
	30
	31	/* max freq cannot be less than 100. But who knows... */
	32	if (unlikely(freq_target == 0))
	33	freq_target = DEF_FREQUENCY_STEP;
	34
	35	return freq_target;
	36	}
	37
4471a34f VK	38	/*
4471a34f VK	39	* Every sampling_rate, we check, if current idle time is less than 20%
7af1c056 SK	40	* (default), then we try to increase frequency. Every sampling_rate *
	41	* sampling_down_factor, we check, if current idle time is more than 80%
	42	* (default), then we try to decrease frequency
4471a34f VK	43	*
	44	* Any frequency increase takes it to the maximum frequency. Frequency reduction
	45	* happens at minimum steps of 5% (default) of maximum frequency
	46	*/
4cccf755	47	static unsigned int cs_dbs_timer(struct cpufreq_policy *policy)
a8d7c3bc	48	{
4cccf755	49	struct cs_cpu_dbs_info_s *dbs_info = &per_cpu(cs_cpu_dbs_info, policy->cpu);
bc505475 RW	50	struct policy_dbs_info *policy_dbs = policy->governor_data;
bc505475 RW	51	struct dbs_data *dbs_data = policy_dbs->dbs_data;
4d5dcc42	52	struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
4cccf755	53	unsigned int load = dbs_update(policy);
4471a34f VK	54
	55	/*
	56	* break out if we 'cannot' reduce the speed as the user might
	57	* want freq_step to be zero
	58	*/
4d5dcc42	59	if (cs_tuners->freq_step == 0)
4cccf755	60	goto out;
4471a34f VK	61
4471a34f VK	62	/* Check for frequency increase */
ff4b1789	63	if (load > dbs_data->up_threshold) {
4471a34f VK	64	dbs_info->down_skip = 0;
	65
	66	/* if we are already at full speed then break out early */
	67	if (dbs_info->requested_freq == policy->max)
4cccf755	68	goto out;
4471a34f	69
98765847	70	dbs_info->requested_freq += get_freq_target(cs_tuners, policy);
a8d7c3bc	71
6d7bcb14 XC	72	if (dbs_info->requested_freq > policy->max)
	73	dbs_info->requested_freq = policy->max;
	74
4471a34f VK	75	__cpufreq_driver_target(policy, dbs_info->requested_freq,
4471a34f VK	76	CPUFREQ_RELATION_H);
4cccf755	77	goto out;
4471a34f VK	78	}
4471a34f VK	79
7af1c056	80	/* if sampling_down_factor is active break out early */
ff4b1789	81	if (++dbs_info->down_skip < dbs_data->sampling_down_factor)
4cccf755	82	goto out;
7af1c056 SK	83	dbs_info->down_skip = 0;
7af1c056 SK	84
27ed3cd2 SK	85	/* Check for frequency decrease */
27ed3cd2 SK	86	if (load < cs_tuners->down_threshold) {
3baa976a	87	unsigned int freq_target;
4471a34f VK	88	/*
	89	* if we cannot reduce the frequency anymore, break out early
	90	*/
	91	if (policy->cur == policy->min)
4cccf755	92	goto out;
4471a34f	93
3baa976a XC	94	freq_target = get_freq_target(cs_tuners, policy);
	95	if (dbs_info->requested_freq > freq_target)
	96	dbs_info->requested_freq -= freq_target;
	97	else
	98	dbs_info->requested_freq = policy->min;
ad529a9c	99
4471a34f	100	__cpufreq_driver_target(policy, dbs_info->requested_freq,
fed573d5	101	CPUFREQ_RELATION_L);
4471a34f	102	}
43e0ee36	103
4cccf755	104	out:
07aa4402	105	return dbs_data->sampling_rate;
66df2a01 FB	106	}
66df2a01 FB	107
4471a34f	108	static int dbs_cpufreq_notifier(struct notifier_block *nb, unsigned long val,
af926185	109	void *data);
a8d7c3bc	110
8e0484d2 VK	111	static struct notifier_block cs_cpufreq_notifier_block = {
	112	.notifier_call = dbs_cpufreq_notifier,
	113	};
	114
b9170836	115	/************************ sysfs interface **********************/
7bdad34d	116	static struct dbs_governor cs_dbs_gov;
b9170836	117
4d5dcc42 VK	118	static ssize_t store_sampling_down_factor(struct dbs_data *dbs_data,
4d5dcc42 VK	119	const char *buf, size_t count)
b9170836 DJ	120	{
	121	unsigned int input;
	122	int ret;
9acef487	123	ret = sscanf(buf, "%u", &input);
8e677ce8	124
2c906b31	125	if (ret != 1 \|\| input > MAX_SAMPLING_DOWN_FACTOR \|\| input < 1)
b9170836 DJ	126	return -EINVAL;
b9170836 DJ	127
ff4b1789	128	dbs_data->sampling_down_factor = input;
b9170836 DJ	129	return count;
	130	}
	131
4d5dcc42 VK	132	static ssize_t store_up_threshold(struct dbs_data dbs_data, const char buf,
4d5dcc42 VK	133	size_t count)
b9170836	134	{
4d5dcc42	135	struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
b9170836 DJ	136	unsigned int input;
b9170836 DJ	137	int ret;
9acef487	138	ret = sscanf(buf, "%u", &input);
b9170836	139
4d5dcc42	140	if (ret != 1 \|\| input > 100 \|\| input <= cs_tuners->down_threshold)
b9170836	141	return -EINVAL;
b9170836	142
ff4b1789	143	dbs_data->up_threshold = input;
b9170836 DJ	144	return count;
	145	}
	146
4d5dcc42 VK	147	static ssize_t store_down_threshold(struct dbs_data dbs_data, const char buf,
4d5dcc42 VK	148	size_t count)
b9170836	149	{
4d5dcc42	150	struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
b9170836 DJ	151	unsigned int input;
b9170836 DJ	152	int ret;
9acef487	153	ret = sscanf(buf, "%u", &input);
b9170836	154
8e677ce8 AC	155	/* cannot be lower than 11 otherwise freq will not fall */
8e677ce8 AC	156	if (ret != 1 \|\| input < 11 \|\| input > 100 \|\|
ff4b1789	157	input >= dbs_data->up_threshold)
b9170836	158	return -EINVAL;
b9170836	159
4d5dcc42	160	cs_tuners->down_threshold = input;
b9170836 DJ	161	return count;
	162	}
	163
6c4640c3 VK	164	static ssize_t store_ignore_nice_load(struct dbs_data *dbs_data,
6c4640c3 VK	165	const char *buf, size_t count)
b9170836	166	{
4471a34f	167	unsigned int input, j;
b9170836 DJ	168	int ret;
b9170836 DJ	169
18a7247d DJ	170	ret = sscanf(buf, "%u", &input);
18a7247d DJ	171	if (ret != 1)
b9170836 DJ	172	return -EINVAL;
b9170836 DJ	173
18a7247d	174	if (input > 1)
b9170836	175	input = 1;
18a7247d	176
ff4b1789	177	if (input == dbs_data->ignore_nice_load) /* nothing to do */
b9170836	178	return count;
326c86de	179
ff4b1789	180	dbs_data->ignore_nice_load = input;
b9170836	181
8e677ce8	182	/* we need to re-evaluate prev_cpu_idle */
dac1c1a5	183	for_each_online_cpu(j) {
4471a34f	184	struct cs_cpu_dbs_info_s *dbs_info;
245b2e70	185	dbs_info = &per_cpu(cs_cpu_dbs_info, j);
4471a34f	186	dbs_info->cdbs.prev_cpu_idle = get_cpu_idle_time(j,
9366d840	187	&dbs_info->cdbs.prev_cpu_wall, 0);
ff4b1789	188	if (dbs_data->ignore_nice_load)
4471a34f VK	189	dbs_info->cdbs.prev_cpu_nice =
4471a34f VK	190	kcpustat_cpu(j).cpustat[CPUTIME_NICE];
b9170836	191	}
b9170836 DJ	192	return count;
	193	}
	194
4d5dcc42 VK	195	static ssize_t store_freq_step(struct dbs_data dbs_data, const char buf,
4d5dcc42 VK	196	size_t count)
b9170836	197	{
4d5dcc42	198	struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
b9170836 DJ	199	unsigned int input;
b9170836 DJ	200	int ret;
18a7247d	201	ret = sscanf(buf, "%u", &input);
b9170836	202
18a7247d	203	if (ret != 1)
b9170836 DJ	204	return -EINVAL;
b9170836 DJ	205
18a7247d	206	if (input > 100)
b9170836	207	input = 100;
18a7247d	208
4471a34f VK	209	/*
	210	* no need to test here if freq_step is zero as the user might actually
	211	* want this, they would be crazy though :)
	212	*/
4d5dcc42	213	cs_tuners->freq_step = input;
b9170836 DJ	214	return count;
	215	}
	216
c4435630 VK	217	gov_show_one_common(sampling_rate);
	218	gov_show_one_common(sampling_down_factor);
	219	gov_show_one_common(up_threshold);
	220	gov_show_one_common(ignore_nice_load);
	221	gov_show_one_common(min_sampling_rate);
	222	gov_show_one(cs, down_threshold);
	223	gov_show_one(cs, freq_step);
	224
	225	gov_attr_rw(sampling_rate);
	226	gov_attr_rw(sampling_down_factor);
	227	gov_attr_rw(up_threshold);
	228	gov_attr_rw(ignore_nice_load);
	229	gov_attr_ro(min_sampling_rate);
	230	gov_attr_rw(down_threshold);
	231	gov_attr_rw(freq_step);
	232
	233	static struct attribute *cs_attributes[] = {
	234	&min_sampling_rate.attr,
	235	&sampling_rate.attr,
	236	&sampling_down_factor.attr,
	237	&up_threshold.attr,
	238	&down_threshold.attr,
	239	&ignore_nice_load.attr,
	240	&freq_step.attr,
b9170836 DJ	241	NULL
	242	};
	243
b9170836 DJ	244	/************************ sysfs end **********************/
b9170836 DJ	245
8e0484d2	246	static int cs_init(struct dbs_data *dbs_data, bool notify)
4d5dcc42 VK	247	{
	248	struct cs_dbs_tuners *tuners;
	249
d5b73cd8	250	tuners = kzalloc(sizeof(*tuners), GFP_KERNEL);
4d5dcc42 VK	251	if (!tuners) {
	252	pr_err("%s: kzalloc failed\n", __func__);
	253	return -ENOMEM;
	254	}
	255
4d5dcc42	256	tuners->down_threshold = DEF_FREQUENCY_DOWN_THRESHOLD;
98765847	257	tuners->freq_step = DEF_FREQUENCY_STEP;
ff4b1789 VK	258	dbs_data->up_threshold = DEF_FREQUENCY_UP_THRESHOLD;
	259	dbs_data->sampling_down_factor = DEF_SAMPLING_DOWN_FACTOR;
	260	dbs_data->ignore_nice_load = 0;
4d5dcc42 VK	261
	262	dbs_data->tuners = tuners;
	263	dbs_data->min_sampling_rate = MIN_SAMPLING_RATE_RATIO *
	264	jiffies_to_usecs(10);
8e0484d2 VK	265
	266	if (notify)
	267	cpufreq_register_notifier(&cs_cpufreq_notifier_block,
	268	CPUFREQ_TRANSITION_NOTIFIER);
	269
4d5dcc42 VK	270	return 0;
	271	}
	272
8e0484d2	273	static void cs_exit(struct dbs_data *dbs_data, bool notify)
4d5dcc42	274	{
8e0484d2 VK	275	if (notify)
	276	cpufreq_unregister_notifier(&cs_cpufreq_notifier_block,
	277	CPUFREQ_TRANSITION_NOTIFIER);
	278
4d5dcc42 VK	279	kfree(dbs_data->tuners);
	280	}
	281
4471a34f	282	define_get_cpu_dbs_routines(cs_cpu_dbs_info);
8e677ce8	283
7bdad34d	284	static struct dbs_governor cs_dbs_gov = {
af926185 RW	285	.gov = {
af926185 RW	286	.name = "conservative",
906a6e5a	287	.governor = cpufreq_governor_dbs,
af926185 RW	288	.max_transition_latency = TRANSITION_LATENCY_LIMIT,
	289	.owner = THIS_MODULE,
	290	},
4471a34f	291	.governor = GOV_CONSERVATIVE,
c4435630	292	.kobj_type = { .default_attrs = cs_attributes },
4471a34f VK	293	.get_cpu_cdbs = get_cpu_cdbs,
	294	.get_cpu_dbs_info_s = get_cpu_dbs_info_s,
	295	.gov_dbs_timer = cs_dbs_timer,
4d5dcc42 VK	296	.init = cs_init,
4d5dcc42 VK	297	.exit = cs_exit,
4471a34f	298	};
b9170836	299
7bdad34d	300	#define CPU_FREQ_GOV_CONSERVATIVE (&cs_dbs_gov.gov)
af926185	301
af926185 RW	302	static int dbs_cpufreq_notifier(struct notifier_block *nb, unsigned long val,
	303	void *data)
	304	{
	305	struct cpufreq_freqs *freq = data;
	306	struct cs_cpu_dbs_info_s *dbs_info =
	307	&per_cpu(cs_cpu_dbs_info, freq->cpu);
	308	struct cpufreq_policy *policy = cpufreq_cpu_get_raw(freq->cpu);
	309
	310	if (!policy)
	311	return 0;
	312
	313	/* policy isn't governed by conservative governor */
	314	if (policy->governor != CPU_FREQ_GOV_CONSERVATIVE)
	315	return 0;
	316
	317	/*
	318	* we only care if our internally tracked freq moves outside the 'valid'
	319	* ranges of frequency available to us otherwise we do not change it
	320	*/
	321	if (dbs_info->requested_freq > policy->max
	322	\|\| dbs_info->requested_freq < policy->min)
	323	dbs_info->requested_freq = freq->new;
	324
	325	return 0;
	326	}
	327
b9170836 DJ	328	static int __init cpufreq_gov_dbs_init(void)
b9170836 DJ	329	{
af926185	330	return cpufreq_register_governor(CPU_FREQ_GOV_CONSERVATIVE);
b9170836 DJ	331	}
	332
	333	static void __exit cpufreq_gov_dbs_exit(void)
	334	{
af926185	335	cpufreq_unregister_governor(CPU_FREQ_GOV_CONSERVATIVE);
b9170836 DJ	336	}
b9170836 DJ	337
11a80a9c	338	MODULE_AUTHOR("Alexander Clouter <alex@digriz.org.uk>");
9acef487	339	MODULE_DESCRIPTION("'cpufreq_conservative' - A dynamic cpufreq governor for "
b9170836 DJ	340	"Low Latency Frequency Transition capable processors "
b9170836 DJ	341	"optimised for use in a battery environment");
9acef487	342	MODULE_LICENSE("GPL");
b9170836	343
6915719b	344	#ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_CONSERVATIVE
de1df26b RW	345	struct cpufreq_governor *cpufreq_default_governor(void)
de1df26b RW	346	{
af926185	347	return CPU_FREQ_GOV_CONSERVATIVE;
de1df26b RW	348	}
de1df26b RW	349
6915719b JW	350	fs_initcall(cpufreq_gov_dbs_init);
6915719b JW	351	#else
b9170836	352	module_init(cpufreq_gov_dbs_init);
6915719b	353	#endif
b9170836	354	module_exit(cpufreq_gov_dbs_exit);