linux/drivers/cpufreq/cpufreq_governor.h
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   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
  17#ifndef _CPUFREQ_GOVERNER_H
  18#define _CPUFREQ_GOVERNER_H
  19
  20#include <linux/cpufreq.h>
  21#include <linux/kobject.h>
  22#include <linux/mutex.h>
  23#include <linux/workqueue.h>
  24#include <linux/sysfs.h>
  25
  26/*
  27 * The polling frequency depends on the capability of the processor. Default
  28 * polling frequency is 1000 times the transition latency of the processor. The
  29 * governor will work on any processor with transition latency <= 10mS, using
  30 * appropriate sampling rate.
  31 *
  32 * For CPUs with transition latency > 10mS (mostly drivers with CPUFREQ_ETERNAL)
  33 * this governor will not work. All times here are in uS.
  34 */
  35#define MIN_SAMPLING_RATE_RATIO                 (2)
  36#define LATENCY_MULTIPLIER                      (1000)
  37#define MIN_LATENCY_MULTIPLIER                  (100)
  38#define TRANSITION_LATENCY_LIMIT                (10 * 1000 * 1000)
  39
  40/* Ondemand Sampling types */
  41enum {OD_NORMAL_SAMPLE, OD_SUB_SAMPLE};
  42
  43/* Macro creating sysfs show routines */
  44#define show_one(_gov, file_name, object)                               \
  45static ssize_t show_##file_name                                         \
  46(struct kobject *kobj, struct attribute *attr, char *buf)               \
  47{                                                                       \
  48        return sprintf(buf, "%u\n", _gov##_tuners.object);              \
  49}
  50
  51#define define_get_cpu_dbs_routines(_dbs_info)                          \
  52static struct cpu_dbs_common_info *get_cpu_cdbs(int cpu)                \
  53{                                                                       \
  54        return &per_cpu(_dbs_info, cpu).cdbs;                           \
  55}                                                                       \
  56                                                                        \
  57static void *get_cpu_dbs_info_s(int cpu)                                \
  58{                                                                       \
  59        return &per_cpu(_dbs_info, cpu);                                \
  60}
  61
  62/*
  63 * Abbreviations:
  64 * dbs: used as a shortform for demand based switching It helps to keep variable
  65 *      names smaller, simpler
  66 * cdbs: common dbs
  67 * on_*: On-demand governor
  68 * cs_*: Conservative governor
  69 */
  70
  71/* Per cpu structures */
  72struct cpu_dbs_common_info {
  73        int cpu;
  74        u64 prev_cpu_idle;
  75        u64 prev_cpu_wall;
  76        u64 prev_cpu_nice;
  77        struct cpufreq_policy *cur_policy;
  78        struct delayed_work work;
  79        /*
  80         * percpu mutex that serializes governor limit change with gov_dbs_timer
  81         * invocation. We do not want gov_dbs_timer to run when user is changing
  82         * the governor or limits.
  83         */
  84        struct mutex timer_mutex;
  85};
  86
  87struct od_cpu_dbs_info_s {
  88        struct cpu_dbs_common_info cdbs;
  89        u64 prev_cpu_iowait;
  90        struct cpufreq_frequency_table *freq_table;
  91        unsigned int freq_lo;
  92        unsigned int freq_lo_jiffies;
  93        unsigned int freq_hi_jiffies;
  94        unsigned int rate_mult;
  95        unsigned int sample_type:1;
  96};
  97
  98struct cs_cpu_dbs_info_s {
  99        struct cpu_dbs_common_info cdbs;
 100        unsigned int down_skip;
 101        unsigned int requested_freq;
 102        unsigned int enable:1;
 103};
 104
 105/* Governers sysfs tunables */
 106struct od_dbs_tuners {
 107        unsigned int ignore_nice;
 108        unsigned int sampling_rate;
 109        unsigned int sampling_down_factor;
 110        unsigned int up_threshold;
 111        unsigned int down_differential;
 112        unsigned int powersave_bias;
 113        unsigned int io_is_busy;
 114};
 115
 116struct cs_dbs_tuners {
 117        unsigned int ignore_nice;
 118        unsigned int sampling_rate;
 119        unsigned int sampling_down_factor;
 120        unsigned int up_threshold;
 121        unsigned int down_threshold;
 122        unsigned int freq_step;
 123};
 124
 125/* Per Governer data */
 126struct dbs_data {
 127        /* Common across governors */
 128        #define GOV_ONDEMAND            0
 129        #define GOV_CONSERVATIVE        1
 130        int governor;
 131        unsigned int min_sampling_rate;
 132        unsigned int enable; /* number of CPUs using this policy */
 133        struct attribute_group *attr_group;
 134        void *tuners;
 135
 136        /* dbs_mutex protects dbs_enable in governor start/stop */
 137        struct mutex mutex;
 138
 139        struct cpu_dbs_common_info *(*get_cpu_cdbs)(int cpu);
 140        void *(*get_cpu_dbs_info_s)(int cpu);
 141        void (*gov_dbs_timer)(struct work_struct *work);
 142        void (*gov_check_cpu)(int cpu, unsigned int load);
 143
 144        /* Governor specific ops, see below */
 145        void *gov_ops;
 146};
 147
 148/* Governor specific ops, will be passed to dbs_data->gov_ops */
 149struct od_ops {
 150        int (*io_busy)(void);
 151        void (*powersave_bias_init_cpu)(int cpu);
 152        unsigned int (*powersave_bias_target)(struct cpufreq_policy *policy,
 153                        unsigned int freq_next, unsigned int relation);
 154        void (*freq_increase)(struct cpufreq_policy *p, unsigned int freq);
 155};
 156
 157struct cs_ops {
 158        struct notifier_block *notifier_block;
 159};
 160
 161static inline int delay_for_sampling_rate(unsigned int sampling_rate)
 162{
 163        int delay = usecs_to_jiffies(sampling_rate);
 164
 165        /* We want all CPUs to do sampling nearly on same jiffy */
 166        if (num_online_cpus() > 1)
 167                delay -= jiffies % delay;
 168
 169        return delay;
 170}
 171
 172u64 get_cpu_idle_time(unsigned int cpu, u64 *wall);
 173void dbs_check_cpu(struct dbs_data *dbs_data, int cpu);
 174int cpufreq_governor_dbs(struct dbs_data *dbs_data,
 175                struct cpufreq_policy *policy, unsigned int event);
 176#endif /* _CPUFREQ_GOVERNER_H */
 177
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