[GitHub/mt8127/android_kernel_alcatel_ttab.git] / drivers / cpufreq / cpufreq_governor.c

/*
 * drivers/cpufreq/cpufreq_governor.c
 *
 * CPUFREQ governors common code
 *
 * Copyright	(C) 2001 Russell King
 *		(C) 2003 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>.
 *		(C) 2003 Jun Nakajima <jun.nakajima@intel.com>
 *		(C) 2009 Alexander Clouter <alex@digriz.org.uk>
 *		(c) 2012 Viresh Kumar <viresh.kumar@linaro.org>
 *
 * 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.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <asm/cputime.h>
#include <linux/cpufreq.h>
#include <linux/cpumask.h>
#include <linux/export.h>
#include <linux/kernel_stat.h>
#include <linux/mutex.h>
#include <linux/tick.h>
#include <linux/types.h>
#include <linux/workqueue.h>

#include "cpufreq_governor.h"

static inline u64 get_cpu_idle_time_jiffy(unsigned int cpu, u64 *wall)
{
	u64 idle_time;
	u64 cur_wall_time;
	u64 busy_time;

	cur_wall_time = jiffies64_to_cputime64(get_jiffies_64());

	busy_time = kcpustat_cpu(cpu).cpustat[CPUTIME_USER];
	busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SYSTEM];
	busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_IRQ];
	busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SOFTIRQ];
	busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_STEAL];
	busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_NICE];

	idle_time = cur_wall_time - busy_time;
	if (wall)
		*wall = cputime_to_usecs(cur_wall_time);

	return cputime_to_usecs(idle_time);
}

u64 get_cpu_idle_time(unsigned int cpu, u64 *wall)
{
	u64 idle_time = get_cpu_idle_time_us(cpu, NULL);

	if (idle_time == -1ULL)
		return get_cpu_idle_time_jiffy(cpu, wall);
	else
		idle_time += get_cpu_iowait_time_us(cpu, wall);

	return idle_time;
}
EXPORT_SYMBOL_GPL(get_cpu_idle_time);

void dbs_check_cpu(struct dbs_data *dbs_data, int cpu)
{
	struct cpu_dbs_common_info *cdbs = dbs_data->get_cpu_cdbs(cpu);
	struct od_dbs_tuners *od_tuners = dbs_data->tuners;
	struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
	struct cpufreq_policy *policy;
	unsigned int max_load = 0;
	unsigned int ignore_nice;
	unsigned int j;

	if (dbs_data->governor == GOV_ONDEMAND)
		ignore_nice = od_tuners->ignore_nice;
	else
		ignore_nice = cs_tuners->ignore_nice;

	policy = cdbs->cur_policy;

	/* Get Absolute Load (in terms of freq for ondemand gov) */
	for_each_cpu(j, policy->cpus) {
		struct cpu_dbs_common_info *j_cdbs;
		u64 cur_wall_time, cur_idle_time, cur_iowait_time;
		unsigned int idle_time, wall_time, iowait_time;
		unsigned int load;

		j_cdbs = dbs_data->get_cpu_cdbs(j);

		cur_idle_time = get_cpu_idle_time(j, &cur_wall_time);

		wall_time = (unsigned int)
			(cur_wall_time - j_cdbs->prev_cpu_wall);
		j_cdbs->prev_cpu_wall = cur_wall_time;

		idle_time = (unsigned int)
			(cur_idle_time - j_cdbs->prev_cpu_idle);
		j_cdbs->prev_cpu_idle = cur_idle_time;

		if (ignore_nice) {
			u64 cur_nice;
			unsigned long cur_nice_jiffies;

			cur_nice = kcpustat_cpu(j).cpustat[CPUTIME_NICE] -
					 cdbs->prev_cpu_nice;
			/*
			 * Assumption: nice time between sampling periods will
			 * be less than 2^32 jiffies for 32 bit sys
			 */
			cur_nice_jiffies = (unsigned long)
					cputime64_to_jiffies64(cur_nice);

			cdbs->prev_cpu_nice =
				kcpustat_cpu(j).cpustat[CPUTIME_NICE];
			idle_time += jiffies_to_usecs(cur_nice_jiffies);
		}

		if (dbs_data->governor == GOV_ONDEMAND) {
			struct od_cpu_dbs_info_s *od_j_dbs_info =
				dbs_data->get_cpu_dbs_info_s(cpu);

			cur_iowait_time = get_cpu_iowait_time_us(j,
					&cur_wall_time);
			if (cur_iowait_time == -1ULL)
				cur_iowait_time = 0;

			iowait_time = (unsigned int) (cur_iowait_time -
					od_j_dbs_info->prev_cpu_iowait);
			od_j_dbs_info->prev_cpu_iowait = cur_iowait_time;

			/*
			 * For the purpose of ondemand, waiting for disk IO is
			 * an indication that you're performance critical, and
			 * not that the system is actually idle. So subtract the
			 * iowait time from the cpu idle time.
			 */
			if (od_tuners->io_is_busy && idle_time >= iowait_time)
				idle_time -= iowait_time;
		}

		if (unlikely(!wall_time || wall_time < idle_time))
			continue;

		load = 100 * (wall_time - idle_time) / wall_time;

		if (dbs_data->governor == GOV_ONDEMAND) {
			int freq_avg = __cpufreq_driver_getavg(policy, j);
			if (freq_avg <= 0)
				freq_avg = policy->cur;

			load *= freq_avg;
		}

		if (load > max_load)
			max_load = load;
	}

	dbs_data->gov_check_cpu(cpu, max_load);
}
EXPORT_SYMBOL_GPL(dbs_check_cpu);

static inline void dbs_timer_init(struct dbs_data *dbs_data, int cpu,
				  unsigned int sampling_rate)
{
	int delay = delay_for_sampling_rate(sampling_rate);
	struct cpu_dbs_common_info *cdbs = dbs_data->get_cpu_cdbs(cpu);

	schedule_delayed_work_on(cpu, &cdbs->work, delay);
}

static inline void dbs_timer_exit(struct dbs_data *dbs_data, int cpu)
{
	struct cpu_dbs_common_info *cdbs = dbs_data->get_cpu_cdbs(cpu);

	cancel_delayed_work_sync(&cdbs->work);
}

/* Will return if we need to evaluate cpu load again or not */
bool need_load_eval(struct cpu_dbs_common_info *cdbs,
		unsigned int sampling_rate)
{
	if (policy_is_shared(cdbs->cur_policy)) {
		ktime_t time_now = ktime_get();
		s64 delta_us = ktime_us_delta(time_now, cdbs->time_stamp);

		/* Do nothing if we recently have sampled */
		if (delta_us < (s64)(sampling_rate / 2))
			return false;
		else
			cdbs->time_stamp = time_now;
	}

	return true;
}
EXPORT_SYMBOL_GPL(need_load_eval);

int cpufreq_governor_dbs(struct dbs_data *dbs_data,
		struct cpufreq_policy *policy, unsigned int event)
{
	struct od_cpu_dbs_info_s *od_dbs_info = NULL;
	struct cs_cpu_dbs_info_s *cs_dbs_info = NULL;
	struct cs_ops *cs_ops = NULL;
	struct od_ops *od_ops = NULL;
	struct od_dbs_tuners *od_tuners = dbs_data->tuners;
	struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
	struct cpu_dbs_common_info *cpu_cdbs;
	unsigned int *sampling_rate, latency, ignore_nice, j, cpu = policy->cpu;
	int rc;

	cpu_cdbs = dbs_data->get_cpu_cdbs(cpu);

	if (dbs_data->governor == GOV_CONSERVATIVE) {
		cs_dbs_info = dbs_data->get_cpu_dbs_info_s(cpu);
		sampling_rate = &cs_tuners->sampling_rate;
		ignore_nice = cs_tuners->ignore_nice;
		cs_ops = dbs_data->gov_ops;
	} else {
		od_dbs_info = dbs_data->get_cpu_dbs_info_s(cpu);
		sampling_rate = &od_tuners->sampling_rate;
		ignore_nice = od_tuners->ignore_nice;
		od_ops = dbs_data->gov_ops;
	}

	switch (event) {
	case CPUFREQ_GOV_START:
		if (!policy->cur)
			return -EINVAL;

		mutex_lock(&dbs_data->mutex);

		for_each_cpu(j, policy->cpus) {
			struct cpu_dbs_common_info *j_cdbs =
				dbs_data->get_cpu_cdbs(j);

			j_cdbs->cpu = j;
			j_cdbs->cur_policy = policy;
			j_cdbs->prev_cpu_idle = get_cpu_idle_time(j,
					&j_cdbs->prev_cpu_wall);
			if (ignore_nice)
				j_cdbs->prev_cpu_nice =
					kcpustat_cpu(j).cpustat[CPUTIME_NICE];

			mutex_init(&j_cdbs->timer_mutex);
			INIT_DEFERRABLE_WORK(&j_cdbs->work,
					     dbs_data->gov_dbs_timer);
		}

		if (!policy->governor->initialized) {
			rc = sysfs_create_group(cpufreq_global_kobject,
					dbs_data->attr_group);
			if (rc) {
				mutex_unlock(&dbs_data->mutex);
				return rc;
			}
		}

		/*
		 * conservative does not implement micro like ondemand
		 * governor, thus we are bound to jiffes/HZ
		 */
		if (dbs_data->governor == GOV_CONSERVATIVE) {
			cs_dbs_info->down_skip = 0;
			cs_dbs_info->enable = 1;
			cs_dbs_info->requested_freq = policy->cur;

			if (!policy->governor->initialized) {
				cpufreq_register_notifier(cs_ops->notifier_block,
						CPUFREQ_TRANSITION_NOTIFIER);

				dbs_data->min_sampling_rate =
					MIN_SAMPLING_RATE_RATIO *
					jiffies_to_usecs(10);
			}
		} else {
			od_dbs_info->rate_mult = 1;
			od_dbs_info->sample_type = OD_NORMAL_SAMPLE;
			od_ops->powersave_bias_init_cpu(cpu);

			if (!policy->governor->initialized)
				od_tuners->io_is_busy = od_ops->io_busy();
		}

		if (policy->governor->initialized)
			goto unlock;

		/* policy latency is in nS. Convert it to uS first */
		latency = policy->cpuinfo.transition_latency / 1000;
		if (latency == 0)
			latency = 1;

		/* Bring kernel and HW constraints together */
		dbs_data->min_sampling_rate = max(dbs_data->min_sampling_rate,
				MIN_LATENCY_MULTIPLIER * latency);
		*sampling_rate = max(dbs_data->min_sampling_rate, latency *
				LATENCY_MULTIPLIER);
unlock:
		mutex_unlock(&dbs_data->mutex);

		/* Initiate timer time stamp */
		cpu_cdbs->time_stamp = ktime_get();

		for_each_cpu(j, policy->cpus)
			dbs_timer_init(dbs_data, j, *sampling_rate);
		break;

	case CPUFREQ_GOV_STOP:
		if (dbs_data->governor == GOV_CONSERVATIVE)
			cs_dbs_info->enable = 0;

		for_each_cpu(j, policy->cpus)
			dbs_timer_exit(dbs_data, j);

		mutex_lock(&dbs_data->mutex);
		mutex_destroy(&cpu_cdbs->timer_mutex);

		if (policy->governor->initialized == 1) {
			sysfs_remove_group(cpufreq_global_kobject,
					dbs_data->attr_group);
			if (dbs_data->governor == GOV_CONSERVATIVE)
				cpufreq_unregister_notifier(cs_ops->notifier_block,
						CPUFREQ_TRANSITION_NOTIFIER);
		}
		mutex_unlock(&dbs_data->mutex);

		break;

	case CPUFREQ_GOV_LIMITS:
		mutex_lock(&cpu_cdbs->timer_mutex);
		if (policy->max < cpu_cdbs->cur_policy->cur)
			__cpufreq_driver_target(cpu_cdbs->cur_policy,
					policy->max, CPUFREQ_RELATION_H);
		else if (policy->min > cpu_cdbs->cur_policy->cur)
			__cpufreq_driver_target(cpu_cdbs->cur_policy,
					policy->min, CPUFREQ_RELATION_L);
		dbs_check_cpu(dbs_data, cpu);
		mutex_unlock(&cpu_cdbs->timer_mutex);
		break;
	}
	return 0;
}
EXPORT_SYMBOL_GPL(cpufreq_governor_dbs);
Commit	Line	Data
2aacdfff	1	/*
	2	* drivers/cpufreq/cpufreq_governor.c
	3	*
	4	* CPUFREQ governors common code
	5	*
4471a34f VK	6	* Copyright (C) 2001 Russell King
	7	* (C) 2003 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>.
	8	* (C) 2003 Jun Nakajima <jun.nakajima@intel.com>
	9	* (C) 2009 Alexander Clouter <alex@digriz.org.uk>
	10	* (c) 2012 Viresh Kumar <viresh.kumar@linaro.org>
	11	*
2aacdfff	12	* This program is free software; you can redistribute it and/or modify
	13	* it under the terms of the GNU General Public License version 2 as
	14	* published by the Free Software Foundation.
	15	*/
	16
4471a34f VK	17	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
4471a34f VK	18
2aacdfff	19	#include <asm/cputime.h>
4471a34f VK	20	#include <linux/cpufreq.h>
4471a34f VK	21	#include <linux/cpumask.h>
2aacdfff	22	#include <linux/export.h>
2aacdfff	23	#include <linux/kernel_stat.h>
4471a34f	24	#include <linux/mutex.h>
2aacdfff	25	#include <linux/tick.h>
2aacdfff	26	#include <linux/types.h>
4471a34f VK	27	#include <linux/workqueue.h>
	28
	29	#include "cpufreq_governor.h"
	30
2aacdfff	31	static inline u64 get_cpu_idle_time_jiffy(unsigned int cpu, u64 *wall)
	32	{
	33	u64 idle_time;
	34	u64 cur_wall_time;
	35	u64 busy_time;
	36
	37	cur_wall_time = jiffies64_to_cputime64(get_jiffies_64());
	38
	39	busy_time = kcpustat_cpu(cpu).cpustat[CPUTIME_USER];
	40	busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SYSTEM];
	41	busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_IRQ];
	42	busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SOFTIRQ];
	43	busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_STEAL];
	44	busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_NICE];
	45
	46	idle_time = cur_wall_time - busy_time;
	47	if (wall)
a0e5af3c	48	*wall = cputime_to_usecs(cur_wall_time);
2aacdfff	49
a0e5af3c	50	return cputime_to_usecs(idle_time);
2aacdfff	51	}
2aacdfff	52
1e7586a1	53	u64 get_cpu_idle_time(unsigned int cpu, u64 *wall)
2aacdfff	54	{
	55	u64 idle_time = get_cpu_idle_time_us(cpu, NULL);
	56
	57	if (idle_time == -1ULL)
	58	return get_cpu_idle_time_jiffy(cpu, wall);
	59	else
	60	idle_time += get_cpu_iowait_time_us(cpu, wall);
	61
	62	return idle_time;
	63	}
	64	EXPORT_SYMBOL_GPL(get_cpu_idle_time);
4471a34f VK	65
	66	void dbs_check_cpu(struct dbs_data *dbs_data, int cpu)
	67	{
	68	struct cpu_dbs_common_info *cdbs = dbs_data->get_cpu_cdbs(cpu);
	69	struct od_dbs_tuners *od_tuners = dbs_data->tuners;
	70	struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
	71	struct cpufreq_policy *policy;
	72	unsigned int max_load = 0;
	73	unsigned int ignore_nice;
	74	unsigned int j;
	75
	76	if (dbs_data->governor == GOV_ONDEMAND)
	77	ignore_nice = od_tuners->ignore_nice;
	78	else
	79	ignore_nice = cs_tuners->ignore_nice;
	80
	81	policy = cdbs->cur_policy;
	82
	83	/* Get Absolute Load (in terms of freq for ondemand gov) */
	84	for_each_cpu(j, policy->cpus) {
	85	struct cpu_dbs_common_info *j_cdbs;
1e7586a1	86	u64 cur_wall_time, cur_idle_time, cur_iowait_time;
4471a34f VK	87	unsigned int idle_time, wall_time, iowait_time;
	88	unsigned int load;
	89
	90	j_cdbs = dbs_data->get_cpu_cdbs(j);
	91
	92	cur_idle_time = get_cpu_idle_time(j, &cur_wall_time);
	93
	94	wall_time = (unsigned int)
	95	(cur_wall_time - j_cdbs->prev_cpu_wall);
	96	j_cdbs->prev_cpu_wall = cur_wall_time;
	97
	98	idle_time = (unsigned int)
	99	(cur_idle_time - j_cdbs->prev_cpu_idle);
	100	j_cdbs->prev_cpu_idle = cur_idle_time;
	101
	102	if (ignore_nice) {
	103	u64 cur_nice;
	104	unsigned long cur_nice_jiffies;
	105
	106	cur_nice = kcpustat_cpu(j).cpustat[CPUTIME_NICE] -
	107	cdbs->prev_cpu_nice;
	108	/*
	109	* Assumption: nice time between sampling periods will
	110	* be less than 2^32 jiffies for 32 bit sys
	111	*/
	112	cur_nice_jiffies = (unsigned long)
	113	cputime64_to_jiffies64(cur_nice);
	114
	115	cdbs->prev_cpu_nice =
	116	kcpustat_cpu(j).cpustat[CPUTIME_NICE];
	117	idle_time += jiffies_to_usecs(cur_nice_jiffies);
	118	}
	119
	120	if (dbs_data->governor == GOV_ONDEMAND) {
	121	struct od_cpu_dbs_info_s *od_j_dbs_info =
	122	dbs_data->get_cpu_dbs_info_s(cpu);
	123
	124	cur_iowait_time = get_cpu_iowait_time_us(j,
	125	&cur_wall_time);
	126	if (cur_iowait_time == -1ULL)
	127	cur_iowait_time = 0;
	128
	129	iowait_time = (unsigned int) (cur_iowait_time -
	130	od_j_dbs_info->prev_cpu_iowait);
	131	od_j_dbs_info->prev_cpu_iowait = cur_iowait_time;
	132
	133	/*
	134	* For the purpose of ondemand, waiting for disk IO is
	135	* an indication that you're performance critical, and
	136	* not that the system is actually idle. So subtract the
	137	* iowait time from the cpu idle time.
	138	*/
	139	if (od_tuners->io_is_busy && idle_time >= iowait_time)
	140	idle_time -= iowait_time;
	141	}
	142
	143	if (unlikely(!wall_time \|\| wall_time < idle_time))
	144	continue;
	145
	146	load = 100 * (wall_time - idle_time) / wall_time;
	147
	148	if (dbs_data->governor == GOV_ONDEMAND) {
	149	int freq_avg = __cpufreq_driver_getavg(policy, j);
	150	if (freq_avg <= 0)
151	freq_avg = policy->cur;
152
153	load *= freq_avg;
154	}
155
156	if (load > max_load)
157	max_load = load;
158	}
159
160	dbs_data->gov_check_cpu(cpu, max_load);
161	}
162	EXPORT_SYMBOL_GPL(dbs_check_cpu);
163
58ddcead FB	164	static inline void dbs_timer_init(struct dbs_data *dbs_data, int cpu,
58ddcead FB	165	unsigned int sampling_rate)
4471a34f VK	166	{
4471a34f VK	167	int delay = delay_for_sampling_rate(sampling_rate);
58ddcead	168	struct cpu_dbs_common_info *cdbs = dbs_data->get_cpu_cdbs(cpu);
4471a34f	169
58ddcead	170	schedule_delayed_work_on(cpu, &cdbs->work, delay);
4471a34f VK	171	}
4471a34f VK	172
58ddcead	173	static inline void dbs_timer_exit(struct dbs_data *dbs_data, int cpu)
4471a34f	174	{
58ddcead FB	175	struct cpu_dbs_common_info *cdbs = dbs_data->get_cpu_cdbs(cpu);
58ddcead FB	176
4471a34f VK	177	cancel_delayed_work_sync(&cdbs->work);
	178	}
	179
4447266b VK	180	/* Will return if we need to evaluate cpu load again or not */
	181	bool need_load_eval(struct cpu_dbs_common_info *cdbs,
	182	unsigned int sampling_rate)
	183	{
	184	if (policy_is_shared(cdbs->cur_policy)) {
	185	ktime_t time_now = ktime_get();
	186	s64 delta_us = ktime_us_delta(time_now, cdbs->time_stamp);
	187
	188	/* Do nothing if we recently have sampled */
	189	if (delta_us < (s64)(sampling_rate / 2))
	190	return false;
	191	else
	192	cdbs->time_stamp = time_now;
	193	}
	194
	195	return true;
	196	}
	197	EXPORT_SYMBOL_GPL(need_load_eval);
	198
4471a34f VK	199	int cpufreq_governor_dbs(struct dbs_data *dbs_data,
	200	struct cpufreq_policy *policy, unsigned int event)
	201	{
	202	struct od_cpu_dbs_info_s *od_dbs_info = NULL;
	203	struct cs_cpu_dbs_info_s *cs_dbs_info = NULL;
8eeed095 VK	204	struct cs_ops *cs_ops = NULL;
8eeed095 VK	205	struct od_ops *od_ops = NULL;
4471a34f VK	206	struct od_dbs_tuners *od_tuners = dbs_data->tuners;
	207	struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
	208	struct cpu_dbs_common_info *cpu_cdbs;
	209	unsigned int *sampling_rate, latency, ignore_nice, j, cpu = policy->cpu;
	210	int rc;
	211
	212	cpu_cdbs = dbs_data->get_cpu_cdbs(cpu);
	213
	214	if (dbs_data->governor == GOV_CONSERVATIVE) {
	215	cs_dbs_info = dbs_data->get_cpu_dbs_info_s(cpu);
	216	sampling_rate = &cs_tuners->sampling_rate;
	217	ignore_nice = cs_tuners->ignore_nice;
8eeed095	218	cs_ops = dbs_data->gov_ops;
4471a34f VK	219	} else {
	220	od_dbs_info = dbs_data->get_cpu_dbs_info_s(cpu);
	221	sampling_rate = &od_tuners->sampling_rate;
	222	ignore_nice = od_tuners->ignore_nice;
8eeed095	223	od_ops = dbs_data->gov_ops;
4471a34f VK	224	}
	225
	226	switch (event) {
	227	case CPUFREQ_GOV_START:
3361b7b1	228	if (!policy->cur)
4471a34f VK	229	return -EINVAL;
	230
	231	mutex_lock(&dbs_data->mutex);
	232
4471a34f	233	for_each_cpu(j, policy->cpus) {
8eeed095 VK	234	struct cpu_dbs_common_info *j_cdbs =
8eeed095 VK	235	dbs_data->get_cpu_cdbs(j);
4471a34f	236
09dca5ae	237	j_cdbs->cpu = j;
4471a34f VK	238	j_cdbs->cur_policy = policy;
	239	j_cdbs->prev_cpu_idle = get_cpu_idle_time(j,
	240	&j_cdbs->prev_cpu_wall);
	241	if (ignore_nice)
	242	j_cdbs->prev_cpu_nice =
	243	kcpustat_cpu(j).cpustat[CPUTIME_NICE];
2abfa876 RA	244
	245	mutex_init(&j_cdbs->timer_mutex);
	246	INIT_DEFERRABLE_WORK(&j_cdbs->work,
	247	dbs_data->gov_dbs_timer);
4471a34f VK	248	}
4471a34f VK	249
8e53695f VK	250	if (!policy->governor->initialized) {
	251	rc = sysfs_create_group(cpufreq_global_kobject,
	252	dbs_data->attr_group);
	253	if (rc) {
	254	mutex_unlock(&dbs_data->mutex);
	255	return rc;
	256	}
4471a34f VK	257	}
4471a34f VK	258
4471a34f VK	259	/*
	260	* conservative does not implement micro like ondemand
	261	* governor, thus we are bound to jiffes/HZ
	262	*/
	263	if (dbs_data->governor == GOV_CONSERVATIVE) {
8eeed095 VK	264	cs_dbs_info->down_skip = 0;
	265	cs_dbs_info->enable = 1;
	266	cs_dbs_info->requested_freq = policy->cur;
4471a34f	267
8e53695f VK	268	if (!policy->governor->initialized) {
	269	cpufreq_register_notifier(cs_ops->notifier_block,
	270	CPUFREQ_TRANSITION_NOTIFIER);
	271
b394058f VK	272	dbs_data->min_sampling_rate =
	273	MIN_SAMPLING_RATE_RATIO *
	274	jiffies_to_usecs(10);
8e53695f	275	}
4471a34f	276	} else {
8eeed095 VK	277	od_dbs_info->rate_mult = 1;
	278	od_dbs_info->sample_type = OD_NORMAL_SAMPLE;
	279	od_ops->powersave_bias_init_cpu(cpu);
b394058f VK	280
	281	if (!policy->governor->initialized)
	282	od_tuners->io_is_busy = od_ops->io_busy();
4471a34f VK	283	}
4471a34f VK	284
b394058f VK	285	if (policy->governor->initialized)
	286	goto unlock;
	287
	288	/* policy latency is in nS. Convert it to uS first */
	289	latency = policy->cpuinfo.transition_latency / 1000;
	290	if (latency == 0)
	291	latency = 1;
	292
4471a34f VK	293	/* Bring kernel and HW constraints together */
	294	dbs_data->min_sampling_rate = max(dbs_data->min_sampling_rate,
	295	MIN_LATENCY_MULTIPLIER * latency);
	296	sampling_rate = max(dbs_data->min_sampling_rate, latency
	297	LATENCY_MULTIPLIER);
b394058f	298	unlock:
4471a34f VK	299	mutex_unlock(&dbs_data->mutex);
4471a34f VK	300
58ddcead FB	301	/* Initiate timer time stamp */
58ddcead FB	302	cpu_cdbs->time_stamp = ktime_get();
da53d61e	303
58ddcead FB	304	for_each_cpu(j, policy->cpus)
58ddcead FB	305	dbs_timer_init(dbs_data, j, *sampling_rate);
4471a34f VK	306	break;
	307
	308	case CPUFREQ_GOV_STOP:
	309	if (dbs_data->governor == GOV_CONSERVATIVE)
	310	cs_dbs_info->enable = 0;
	311
58ddcead FB	312	for_each_cpu(j, policy->cpus)
58ddcead FB	313	dbs_timer_exit(dbs_data, j);
4471a34f VK	314
	315	mutex_lock(&dbs_data->mutex);
	316	mutex_destroy(&cpu_cdbs->timer_mutex);
8eeed095	317
8e53695f VK	318	if (policy->governor->initialized == 1) {
	319	sysfs_remove_group(cpufreq_global_kobject,
	320	dbs_data->attr_group);
	321	if (dbs_data->governor == GOV_CONSERVATIVE)
	322	cpufreq_unregister_notifier(cs_ops->notifier_block,
	323	CPUFREQ_TRANSITION_NOTIFIER);
	324	}
4471a34f VK	325	mutex_unlock(&dbs_data->mutex);
	326
	327	break;
	328
	329	case CPUFREQ_GOV_LIMITS:
	330	mutex_lock(&cpu_cdbs->timer_mutex);
	331	if (policy->max < cpu_cdbs->cur_policy->cur)
	332	__cpufreq_driver_target(cpu_cdbs->cur_policy,
	333	policy->max, CPUFREQ_RELATION_H);
	334	else if (policy->min > cpu_cdbs->cur_policy->cur)
	335	__cpufreq_driver_target(cpu_cdbs->cur_policy,
	336	policy->min, CPUFREQ_RELATION_L);
	337	dbs_check_cpu(dbs_data, cpu);
	338	mutex_unlock(&cpu_cdbs->timer_mutex);
	339	break;
	340	}
	341	return 0;
	342	}
	343	EXPORT_SYMBOL_GPL(cpufreq_governor_dbs);