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/*
* 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};
struct gov_attr_set {
struct kobject kobj;
struct list_head policy_list;
struct mutex update_lock;
int usage_count;
};
/*
* 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 {
struct gov_attr_set attr_set;
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;
};
static inline struct dbs_data *to_dbs_data(struct gov_attr_set *attr_set)
{
return container_of(attr_set, struct dbs_data, attr_set);
}
/* Governor's specific attributes */
struct governor_attr {
struct attribute attr;
ssize_t (*show)(struct gov_attr_set *attr_set, char *buf);
ssize_t (*store)(struct gov_attr_set *attr_set, const char *buf,
size_t count);
};
#define gov_show_one(_gov, file_name) \
static ssize_t show_##file_name \
(struct gov_attr_set *attr_set, char *buf) \
{ \
struct dbs_data *dbs_data = to_dbs_data(attr_set); \
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 gov_attr_set *attr_set, char *buf) \
{ \
struct dbs_data *dbs_data = to_dbs_data(attr_set); \
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 gov_attr_set *attr_set, const char *buf,
size_t count);
void gov_update_cpu_data(struct dbs_data *dbs_data);
#endif /* _CPUFREQ_GOVERNOR_H */
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