[linux-2.6-block.git] / drivers / cpufreq / cpufreq_governor.h

/*
 * drivers/cpufreq/cpufreq_governor.h
 *
 * Header file for 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.
 */

#ifndef _CPUFREQ_GOVERNOR_H
#define _CPUFREQ_GOVERNOR_H

#include <linux/atomic.h>
#include <linux/irq_work.h>
#include <linux/cpufreq.h>
#include <linux/kernel_stat.h>
#include <linux/module.h>
#include <linux/mutex.h>

/*
 * The polling frequency depends on the capability of the processor. Default
 * polling frequency is 1000 times the transition latency of the processor. The
 * governor will work on any processor with transition latency <= 10ms, using
 * appropriate sampling rate.
 *
 * For CPUs with transition latency > 10ms (mostly drivers with CPUFREQ_ETERNAL)
 * this governor will not work. All times here are in us (micro seconds).
 */
#define MIN_SAMPLING_RATE_RATIO			(2)
#define LATENCY_MULTIPLIER			(1000)
#define MIN_LATENCY_MULTIPLIER			(20)
#define TRANSITION_LATENCY_LIMIT		(10 * 1000 * 1000)

/* Ondemand Sampling types */
enum {OD_NORMAL_SAMPLE, OD_SUB_SAMPLE};

/*
 * Abbreviations:
 * dbs: used as a shortform for demand based switching It helps to keep variable
 *	names smaller, simpler
 * cdbs: common dbs
 * od_*: On-demand governor
 * cs_*: Conservative governor
 */

/* Governor demand based switching data (per-policy or global). */
struct dbs_data {
	int usage_count;
	void *tuners;
	unsigned int min_sampling_rate;
	unsigned int ignore_nice_load;
	unsigned int sampling_rate;
	unsigned int sampling_down_factor;
	unsigned int up_threshold;
	unsigned int io_is_busy;

	struct kobject kobj;
	struct list_head policy_dbs_list;
	/*
	 * Protect concurrent updates to governor tunables from sysfs,
	 * policy_dbs_list and usage_count.
	 */
	struct mutex mutex;
};

/* Governor's specific attributes */
struct dbs_data;
struct governor_attr {
	struct attribute attr;
	ssize_t (*show)(struct dbs_data *dbs_data, char *buf);
	ssize_t (*store)(struct dbs_data *dbs_data, const char *buf,
			 size_t count);
};

#define gov_show_one(_gov, file_name)					\
static ssize_t show_##file_name						\
(struct dbs_data *dbs_data, char *buf)					\
{									\
	struct _gov##_dbs_tuners *tuners = dbs_data->tuners;		\
	return sprintf(buf, "%u\n", tuners->file_name);			\
}

#define gov_show_one_common(file_name)					\
static ssize_t show_##file_name						\
(struct dbs_data *dbs_data, char *buf)					\
{									\
	return sprintf(buf, "%u\n", dbs_data->file_name);		\
}

#define gov_attr_ro(_name)						\
static struct governor_attr _name =					\
__ATTR(_name, 0444, show_##_name, NULL)

#define gov_attr_rw(_name)						\
static struct governor_attr _name =					\
__ATTR(_name, 0644, show_##_name, store_##_name)

/* Common to all CPUs of a policy */
struct policy_dbs_info {
	struct cpufreq_policy *policy;
	/*
	 * Per policy mutex that serializes load evaluation from limit-change
	 * and work-handler.
	 */
	struct mutex timer_mutex;

	u64 last_sample_time;
	s64 sample_delay_ns;
	atomic_t work_count;
	struct irq_work irq_work;
	struct work_struct work;
	/* dbs_data may be shared between multiple policy objects */
	struct dbs_data *dbs_data;
	struct list_head list;
	/* Multiplier for increasing sample delay temporarily. */
	unsigned int rate_mult;
	/* Status indicators */
	bool is_shared;		/* This object is used by multiple CPUs */
	bool work_in_progress;	/* Work is being queued up or in progress */
};

static inline void gov_update_sample_delay(struct policy_dbs_info *policy_dbs,
					   unsigned int delay_us)
{
	policy_dbs->sample_delay_ns = delay_us * NSEC_PER_USEC;
}

/* Per cpu structures */
struct cpu_dbs_info {
	u64 prev_cpu_idle;
	u64 prev_cpu_wall;
	u64 prev_cpu_nice;
	/*
	 * Used to keep track of load in the previous interval. However, when
	 * explicitly set to zero, it is used as a flag to ensure that we copy
	 * the previous load to the current interval only once, upon the first
	 * wake-up from idle.
	 */
	unsigned int prev_load;
	struct update_util_data update_util;
	struct policy_dbs_info *policy_dbs;
};

/* Common Governor data across policies */
struct dbs_governor {
	struct cpufreq_governor gov;
	struct kobj_type kobj_type;

	/*
	 * Common data for platforms that don't set
	 * CPUFREQ_HAVE_GOVERNOR_PER_POLICY
	 */
	struct dbs_data *gdbs_data;

	unsigned int (*gov_dbs_timer)(struct cpufreq_policy *policy);
	struct policy_dbs_info *(*alloc)(void);
	void (*free)(struct policy_dbs_info *policy_dbs);
	int (*init)(struct dbs_data *dbs_data, bool notify);
	void (*exit)(struct dbs_data *dbs_data, bool notify);
	void (*start)(struct cpufreq_policy *policy);
};

static inline struct dbs_governor *dbs_governor_of(struct cpufreq_policy *policy)
{
	return container_of(policy->governor, struct dbs_governor, gov);
}

/* Governor specific operations */
struct od_ops {
	unsigned int (*powersave_bias_target)(struct cpufreq_policy *policy,
			unsigned int freq_next, unsigned int relation);
};

unsigned int dbs_update(struct cpufreq_policy *policy);
int cpufreq_governor_dbs(struct cpufreq_policy *policy, unsigned int event);
void od_register_powersave_bias_handler(unsigned int (*f)
		(struct cpufreq_policy *, unsigned int, unsigned int),
		unsigned int powersave_bias);
void od_unregister_powersave_bias_handler(void);
ssize_t store_sampling_rate(struct dbs_data *dbs_data, const char *buf,
			    size_t count);
void gov_update_cpu_data(struct dbs_data *dbs_data);
#endif /* _CPUFREQ_GOVERNOR_H */
Commit	Line	Data
4471a34f VK	1	/*
	2	* drivers/cpufreq/cpufreq_governor.h
	3	*
	4	* Header file for CPUFreq governors common code
	5	*
	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	*
	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
beb0ff39 BP	17	#ifndef _CPUFREQ_GOVERNOR_H
beb0ff39 BP	18	#define _CPUFREQ_GOVERNOR_H
4471a34f	19
2dd3e724	20	#include <linux/atomic.h>
9be4fd2c	21	#include <linux/irq_work.h>
4471a34f	22	#include <linux/cpufreq.h>
5ff0a268 VK	23	#include <linux/kernel_stat.h>
5ff0a268 VK	24	#include <linux/module.h>
4471a34f	25	#include <linux/mutex.h>
4471a34f VK	26
	27	/*
	28	* The polling frequency depends on the capability of the processor. Default
	29	* polling frequency is 1000 times the transition latency of the processor. The
c4afc410	30	* governor will work on any processor with transition latency <= 10ms, using
4471a34f VK	31	* appropriate sampling rate.
4471a34f VK	32	*
c4afc410 SK	33	* For CPUs with transition latency > 10ms (mostly drivers with CPUFREQ_ETERNAL)
c4afc410 SK	34	* this governor will not work. All times here are in us (micro seconds).
4471a34f VK	35	*/
	36	#define MIN_SAMPLING_RATE_RATIO (2)
	37	#define LATENCY_MULTIPLIER (1000)
98104ee2	38	#define MIN_LATENCY_MULTIPLIER (20)
4471a34f VK	39	#define TRANSITION_LATENCY_LIMIT (10 * 1000 * 1000)
	40
	41	/* Ondemand Sampling types */
	42	enum {OD_NORMAL_SAMPLE, OD_SUB_SAMPLE};
	43
4471a34f VK	44	/*
	45	* Abbreviations:
	46	* dbs: used as a shortform for demand based switching It helps to keep variable
	47	* names smaller, simpler
	48	* cdbs: common dbs
e5dde92c	49	* od_*: On-demand governor
4471a34f VK	50	* cs_*: Conservative governor
	51	*/
	52
bc505475 RW	53	/* Governor demand based switching data (per-policy or global). */
bc505475 RW	54	struct dbs_data {
bc505475 RW	55	int usage_count;
bc505475 RW	56	void *tuners;
ff4b1789 VK	57	unsigned int min_sampling_rate;
	58	unsigned int ignore_nice_load;
	59	unsigned int sampling_rate;
	60	unsigned int sampling_down_factor;
	61	unsigned int up_threshold;
8847e038	62	unsigned int io_is_busy;
c4435630 VK	63
c4435630 VK	64	struct kobject kobj;
c54df071 VK	65	struct list_head policy_dbs_list;
	66	/*
	67	* Protect concurrent updates to governor tunables from sysfs,
	68	* policy_dbs_list and usage_count.
	69	*/
c4435630 VK	70	struct mutex mutex;
	71	};
	72
	73	/* Governor's specific attributes */
	74	struct dbs_data;
	75	struct governor_attr {
	76	struct attribute attr;
	77	ssize_t (show)(struct dbs_data dbs_data, char *buf);
	78	ssize_t (store)(struct dbs_data dbs_data, const char *buf,
	79	size_t count);
bc505475 RW	80	};
bc505475 RW	81
c4435630 VK	82	#define gov_show_one(_gov, file_name) \
	83	static ssize_t show_##file_name \
	84	(struct dbs_data dbs_data, char buf) \
	85	{ \
	86	struct _gov##_dbs_tuners *tuners = dbs_data->tuners; \
	87	return sprintf(buf, "%u\n", tuners->file_name); \
	88	}
	89
	90	#define gov_show_one_common(file_name) \
	91	static ssize_t show_##file_name \
	92	(struct dbs_data dbs_data, char buf) \
	93	{ \
	94	return sprintf(buf, "%u\n", dbs_data->file_name); \
	95	}
	96
	97	#define gov_attr_ro(_name) \
	98	static struct governor_attr _name = \
	99	__ATTR(_name, 0444, show_##_name, NULL)
	100
	101	#define gov_attr_rw(_name) \
	102	static struct governor_attr _name = \
	103	__ATTR(_name, 0644, show_##_name, store_##_name)
	104
44152cb8	105	/* Common to all CPUs of a policy */
e40e7b25	106	struct policy_dbs_info {
44152cb8 VK	107	struct cpufreq_policy *policy;
44152cb8 VK	108	/*
70f43e5e VK	109	* Per policy mutex that serializes load evaluation from limit-change
70f43e5e VK	110	* and work-handler.
44152cb8 VK	111	*/
44152cb8 VK	112	struct mutex timer_mutex;
70f43e5e	113
9be4fd2c RW	114	u64 last_sample_time;
9be4fd2c RW	115	s64 sample_delay_ns;
686cc637	116	atomic_t work_count;
9be4fd2c	117	struct irq_work irq_work;
70f43e5e	118	struct work_struct work;
bc505475 RW	119	/* dbs_data may be shared between multiple policy objects */
bc505475 RW	120	struct dbs_data *dbs_data;
c54df071	121	struct list_head list;
57dc3bcd RW	122	/* Multiplier for increasing sample delay temporarily. */
57dc3bcd RW	123	unsigned int rate_mult;
e4db2813 RW	124	/* Status indicators */
	125	bool is_shared; /* This object is used by multiple CPUs */
	126	bool work_in_progress; /* Work is being queued up or in progress */
44152cb8 VK	127	};
44152cb8 VK	128
e40e7b25	129	static inline void gov_update_sample_delay(struct policy_dbs_info *policy_dbs,
9be4fd2c RW	130	unsigned int delay_us)
9be4fd2c RW	131	{
e40e7b25	132	policy_dbs->sample_delay_ns = delay_us * NSEC_PER_USEC;
9be4fd2c RW	133	}
9be4fd2c RW	134
4471a34f	135	/* Per cpu structures */
875b8508	136	struct cpu_dbs_info {
1e7586a1 VK	137	u64 prev_cpu_idle;
	138	u64 prev_cpu_wall;
	139	u64 prev_cpu_nice;
18b46abd	140	/*
c8ae481b VK	141	* Used to keep track of load in the previous interval. However, when
	142	* explicitly set to zero, it is used as a flag to ensure that we copy
	143	* the previous load to the current interval only once, upon the first
	144	* wake-up from idle.
18b46abd	145	*/
c8ae481b	146	unsigned int prev_load;
9be4fd2c	147	struct update_util_data update_util;
e40e7b25	148	struct policy_dbs_info *policy_dbs;
4471a34f VK	149	};
4471a34f VK	150
c4afc410	151	/* Common Governor data across policies */
7bdad34d	152	struct dbs_governor {
af926185	153	struct cpufreq_governor gov;
c4435630	154	struct kobj_type kobj_type;
4471a34f	155
0b981e70 VK	156	/*
	157	* Common data for platforms that don't set
	158	* CPUFREQ_HAVE_GOVERNOR_PER_POLICY
	159	*/
4d5dcc42	160	struct dbs_data *gdbs_data;
4471a34f	161
9be4fd2c	162	unsigned int (gov_dbs_timer)(struct cpufreq_policy policy);
7d5a9956 RW	163	struct policy_dbs_info (alloc)(void);
7d5a9956 RW	164	void (free)(struct policy_dbs_info policy_dbs);
8e0484d2 VK	165	int (init)(struct dbs_data dbs_data, bool notify);
8e0484d2 VK	166	void (exit)(struct dbs_data dbs_data, bool notify);
702c9e54	167	void (start)(struct cpufreq_policy policy);
4471a34f VK	168	};
4471a34f VK	169
ea59ee0d RW	170	static inline struct dbs_governor dbs_governor_of(struct cpufreq_policy policy)
	171	{
	172	return container_of(policy->governor, struct dbs_governor, gov);
	173	}
	174
8434dadb	175	/* Governor specific operations */
4471a34f	176	struct od_ops {
4471a34f VK	177	unsigned int (powersave_bias_target)(struct cpufreq_policy policy,
4471a34f VK	178	unsigned int freq_next, unsigned int relation);
4471a34f VK	179	};
4471a34f VK	180
4cccf755	181	unsigned int dbs_update(struct cpufreq_policy *policy);
906a6e5a	182	int cpufreq_governor_dbs(struct cpufreq_policy *policy, unsigned int event);
fb30809e JS	183	void od_register_powersave_bias_handler(unsigned int (*f)
	184	(struct cpufreq_policy *, unsigned int, unsigned int),
	185	unsigned int powersave_bias);
	186	void od_unregister_powersave_bias_handler(void);
aded387b VK	187	ssize_t store_sampling_rate(struct dbs_data dbs_data, const char buf,
aded387b VK	188	size_t count);
8c8f77fd	189	void gov_update_cpu_data(struct dbs_data *dbs_data);
beb0ff39	190	#endif /* _CPUFREQ_GOVERNOR_H */