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_GOVERNOR_H
  18#define _CPUFREQ_GOVERNOR_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                  (20)
  38#define TRANSITION_LATENCY_LIMIT                (10 * 1000 * 1000)
  39
  40/* Ondemand Sampling types */
  41enum {OD_NORMAL_SAMPLE, OD_SUB_SAMPLE};
  42
  43/*
  44 * Macro for creating governors sysfs routines
  45 *
  46 * - gov_sys: One governor instance per whole system
  47 * - gov_pol: One governor instance per policy
  48 */
  49
  50/* Create attributes */
  51#define gov_sys_attr_ro(_name)                                          \
  52static struct global_attr _name##_gov_sys =                             \
  53__ATTR(_name, 0444, show_##_name##_gov_sys, NULL)
  54
  55#define gov_sys_attr_rw(_name)                                          \
  56static struct global_attr _name##_gov_sys =                             \
  57__ATTR(_name, 0644, show_##_name##_gov_sys, store_##_name##_gov_sys)
  58
  59#define gov_pol_attr_ro(_name)                                          \
  60static struct freq_attr _name##_gov_pol =                               \
  61__ATTR(_name, 0444, show_##_name##_gov_pol, NULL)
  62
  63#define gov_pol_attr_rw(_name)                                          \
  64static struct freq_attr _name##_gov_pol =                               \
  65__ATTR(_name, 0644, show_##_name##_gov_pol, store_##_name##_gov_pol)
  66
  67#define gov_sys_pol_attr_rw(_name)                                      \
  68        gov_sys_attr_rw(_name);                                         \
  69        gov_pol_attr_rw(_name)
  70
  71#define gov_sys_pol_attr_ro(_name)                                      \
  72        gov_sys_attr_ro(_name);                                         \
  73        gov_pol_attr_ro(_name)
  74
  75/* Create show/store routines */
  76#define show_one(_gov, file_name)                                       \
  77static ssize_t show_##file_name##_gov_sys                               \
  78(struct kobject *kobj, struct attribute *attr, char *buf)               \
  79{                                                                       \
  80        struct _gov##_dbs_tuners *tuners = _gov##_dbs_cdata.gdbs_data->tuners; \
  81        return sprintf(buf, "%u\n", tuners->file_name);                 \
  82}                                                                       \
  83                                                                        \
  84static ssize_t show_##file_name##_gov_pol                                       \
  85(struct cpufreq_policy *policy, char *buf)                              \
  86{                                                                       \
  87        struct dbs_data *dbs_data = policy->governor_data;              \
  88        struct _gov##_dbs_tuners *tuners = dbs_data->tuners;            \
  89        return sprintf(buf, "%u\n", tuners->file_name);                 \
  90}
  91
  92#define store_one(_gov, file_name)                                      \
  93static ssize_t store_##file_name##_gov_sys                              \
  94(struct kobject *kobj, struct attribute *attr, const char *buf, size_t count)   \
  95{                                                                       \
  96        struct dbs_data *dbs_data = _gov##_dbs_cdata.gdbs_data;         \
  97        return store_##file_name(dbs_data, buf, count);                 \
  98}                                                                       \
  99                                                                        \
 100static ssize_t store_##file_name##_gov_pol                              \
 101(struct cpufreq_policy *policy, const char *buf, size_t count)          \
 102{                                                                       \
 103        struct dbs_data *dbs_data = policy->governor_data;              \
 104        return store_##file_name(dbs_data, buf, count);                 \
 105}
 106
 107#define show_store_one(_gov, file_name)                                 \
 108show_one(_gov, file_name);                                              \
 109store_one(_gov, file_name)
 110
 111/* create helper routines */
 112#define define_get_cpu_dbs_routines(_dbs_info)                          \
 113static struct cpu_dbs_common_info *get_cpu_cdbs(int cpu)                \
 114{                                                                       \
 115        return &per_cpu(_dbs_info, cpu).cdbs;                           \
 116}                                                                       \
 117                                                                        \
 118static void *get_cpu_dbs_info_s(int cpu)                                \
 119{                                                                       \
 120        return &per_cpu(_dbs_info, cpu);                                \
 121}
 122
 123/*
 124 * Abbreviations:
 125 * dbs: used as a shortform for demand based switching It helps to keep variable
 126 *      names smaller, simpler
 127 * cdbs: common dbs
 128 * od_*: On-demand governor
 129 * cs_*: Conservative governor
 130 */
 131
 132/* Per cpu structures */
 133struct cpu_dbs_common_info {
 134        int cpu;
 135        u64 prev_cpu_idle;
 136        u64 prev_cpu_wall;
 137        u64 prev_cpu_nice;
 138        struct cpufreq_policy *cur_policy;
 139        struct delayed_work work;
 140        /*
 141         * percpu mutex that serializes governor limit change with gov_dbs_timer
 142         * invocation. We do not want gov_dbs_timer to run when user is changing
 143         * the governor or limits.
 144         */
 145        struct mutex timer_mutex;
 146        ktime_t time_stamp;
 147};
 148
 149struct od_cpu_dbs_info_s {
 150        struct cpu_dbs_common_info cdbs;
 151        struct cpufreq_frequency_table *freq_table;
 152        unsigned int freq_lo;
 153        unsigned int freq_lo_jiffies;
 154        unsigned int freq_hi_jiffies;
 155        unsigned int rate_mult;
 156        unsigned int sample_type:1;
 157};
 158
 159struct cs_cpu_dbs_info_s {
 160        struct cpu_dbs_common_info cdbs;
 161        unsigned int down_skip;
 162        unsigned int requested_freq;
 163        unsigned int enable:1;
 164};
 165
 166/* Per policy Governers sysfs tunables */
 167struct od_dbs_tuners {
 168        unsigned int ignore_nice;
 169        unsigned int sampling_rate;
 170        unsigned int sampling_down_factor;
 171        unsigned int up_threshold;
 172        unsigned int adj_up_threshold;
 173        unsigned int powersave_bias;
 174        unsigned int io_is_busy;
 175};
 176
 177struct cs_dbs_tuners {
 178        unsigned int ignore_nice;
 179        unsigned int sampling_rate;
 180        unsigned int sampling_down_factor;
 181        unsigned int up_threshold;
 182        unsigned int down_threshold;
 183        unsigned int freq_step;
 184};
 185
 186/* Common Governer data across policies */
 187struct dbs_data;
 188struct common_dbs_data {
 189        /* Common across governors */
 190        #define GOV_ONDEMAND            0
 191        #define GOV_CONSERVATIVE        1
 192        int governor;
 193        struct attribute_group *attr_group_gov_sys; /* one governor - system */
 194        struct attribute_group *attr_group_gov_pol; /* one governor - policy */
 195
 196        /* Common data for platforms that don't set have_governor_per_policy */
 197        struct dbs_data *gdbs_data;
 198
 199        struct cpu_dbs_common_info *(*get_cpu_cdbs)(int cpu);
 200        void *(*get_cpu_dbs_info_s)(int cpu);
 201        void (*gov_dbs_timer)(struct work_struct *work);
 202        void (*gov_check_cpu)(int cpu, unsigned int load);
 203        int (*init)(struct dbs_data *dbs_data);
 204        void (*exit)(struct dbs_data *dbs_data);
 205
 206        /* Governor specific ops, see below */
 207        void *gov_ops;
 208};
 209
 210/* Governer Per policy data */
 211struct dbs_data {
 212        struct common_dbs_data *cdata;
 213        unsigned int min_sampling_rate;
 214        int usage_count;
 215        void *tuners;
 216
 217        /* dbs_mutex protects dbs_enable in governor start/stop */
 218        struct mutex mutex;
 219};
 220
 221/* Governor specific ops, will be passed to dbs_data->gov_ops */
 222struct od_ops {
 223        void (*powersave_bias_init_cpu)(int cpu);
 224        unsigned int (*powersave_bias_target)(struct cpufreq_policy *policy,
 225                        unsigned int freq_next, unsigned int relation);
 226        void (*freq_increase)(struct cpufreq_policy *p, unsigned int freq);
 227};
 228
 229struct cs_ops {
 230        struct notifier_block *notifier_block;
 231};
 232
 233static inline int delay_for_sampling_rate(unsigned int sampling_rate)
 234{
 235        int delay = usecs_to_jiffies(sampling_rate);
 236
 237        /* We want all CPUs to do sampling nearly on same jiffy */
 238        if (num_online_cpus() > 1)
 239                delay -= jiffies % delay;
 240
 241        return delay;
 242}
 243
 244#define declare_show_sampling_rate_min(_gov)                            \
 245static ssize_t show_sampling_rate_min_gov_sys                           \
 246(struct kobject *kobj, struct attribute *attr, char *buf)               \
 247{                                                                       \
 248        struct dbs_data *dbs_data = _gov##_dbs_cdata.gdbs_data;         \
 249        return sprintf(buf, "%u\n", dbs_data->min_sampling_rate);       \
 250}                                                                       \
 251                                                                        \
 252static ssize_t show_sampling_rate_min_gov_pol                           \
 253(struct cpufreq_policy *policy, char *buf)                              \
 254{                                                                       \
 255        struct dbs_data *dbs_data = policy->governor_data;              \
 256        return sprintf(buf, "%u\n", dbs_data->min_sampling_rate);       \
 257}
 258
 259u64 get_cpu_idle_time(unsigned int cpu, u64 *wall, int io_busy);
 260void dbs_check_cpu(struct dbs_data *dbs_data, int cpu);
 261bool need_load_eval(struct cpu_dbs_common_info *cdbs,
 262                unsigned int sampling_rate);
 263int cpufreq_governor_dbs(struct cpufreq_policy *policy,
 264                struct common_dbs_data *cdata, unsigned int event);
 265void gov_queue_work(struct dbs_data *dbs_data, struct cpufreq_policy *policy,
 266                unsigned int delay, bool all_cpus);
 267void od_register_powersave_bias_handler(unsigned int (*f)
 268                (struct cpufreq_policy *, unsigned int, unsigned int),
 269                unsigned int powersave_bias);
 270void od_unregister_powersave_bias_handler(void);
 271#endif /* _CPUFREQ_GOVERNOR_H */
 272
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