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/kernel_stat.h>
  22#include <linux/module.h>
  23#include <linux/mutex.h>
  24
  25/*
  26 * The polling frequency depends on the capability of the processor. Default
  27 * polling frequency is 1000 times the transition latency of the processor. The
  28 * governor will work on any processor with transition latency <= 10ms, using
  29 * appropriate sampling rate.
  30 *
  31 * For CPUs with transition latency > 10ms (mostly drivers with CPUFREQ_ETERNAL)
  32 * this governor will not work. All times here are in us (micro seconds).
  33 */
  34#define MIN_SAMPLING_RATE_RATIO                 (2)
  35#define LATENCY_MULTIPLIER                      (1000)
  36#define MIN_LATENCY_MULTIPLIER                  (20)
  37#define TRANSITION_LATENCY_LIMIT                (10 * 1000 * 1000)
  38
  39/* Ondemand Sampling types */
  40enum {OD_NORMAL_SAMPLE, OD_SUB_SAMPLE};
  41
  42/*
  43 * Macro for creating governors sysfs routines
  44 *
  45 * - gov_sys: One governor instance per whole system
  46 * - gov_pol: One governor instance per policy
  47 */
  48
  49/* Create attributes */
  50#define gov_sys_attr_ro(_name)                                          \
  51static struct global_attr _name##_gov_sys =                             \
  52__ATTR(_name, 0444, show_##_name##_gov_sys, NULL)
  53
  54#define gov_sys_attr_rw(_name)                                          \
  55static struct global_attr _name##_gov_sys =                             \
  56__ATTR(_name, 0644, show_##_name##_gov_sys, store_##_name##_gov_sys)
  57
  58#define gov_pol_attr_ro(_name)                                          \
  59static struct freq_attr _name##_gov_pol =                               \
  60__ATTR(_name, 0444, show_##_name##_gov_pol, NULL)
  61
  62#define gov_pol_attr_rw(_name)                                          \
  63static struct freq_attr _name##_gov_pol =                               \
  64__ATTR(_name, 0644, show_##_name##_gov_pol, store_##_name##_gov_pol)
  65
  66#define gov_sys_pol_attr_rw(_name)                                      \
  67        gov_sys_attr_rw(_name);                                         \
  68        gov_pol_attr_rw(_name)
  69
  70#define gov_sys_pol_attr_ro(_name)                                      \
  71        gov_sys_attr_ro(_name);                                         \
  72        gov_pol_attr_ro(_name)
  73
  74/* Create show/store routines */
  75#define show_one(_gov, file_name)                                       \
  76static ssize_t show_##file_name##_gov_sys                               \
  77(struct kobject *kobj, struct attribute *attr, char *buf)               \
  78{                                                                       \
  79        struct _gov##_dbs_tuners *tuners = _gov##_dbs_cdata.gdbs_data->tuners; \
  80        return sprintf(buf, "%u\n", tuners->file_name);                 \
  81}                                                                       \
  82                                                                        \
  83static ssize_t show_##file_name##_gov_pol                               \
  84(struct cpufreq_policy *policy, char *buf)                              \
  85{                                                                       \
  86        struct dbs_data *dbs_data = policy->governor_data;              \
  87        struct _gov##_dbs_tuners *tuners = dbs_data->tuners;            \
  88        return sprintf(buf, "%u\n", tuners->file_name);                 \
  89}
  90
  91#define store_one(_gov, file_name)                                      \
  92static ssize_t store_##file_name##_gov_sys                              \
  93(struct kobject *kobj, struct attribute *attr, const char *buf, size_t count) \
  94{                                                                       \
  95        struct dbs_data *dbs_data = _gov##_dbs_cdata.gdbs_data;         \
  96        return store_##file_name(dbs_data, buf, count);                 \
  97}                                                                       \
  98                                                                        \
  99static ssize_t store_##file_name##_gov_pol                              \
 100(struct cpufreq_policy *policy, const char *buf, size_t count)          \
 101{                                                                       \
 102        struct dbs_data *dbs_data = policy->governor_data;              \
 103        return store_##file_name(dbs_data, buf, count);                 \
 104}
 105
 106#define show_store_one(_gov, file_name)                                 \
 107show_one(_gov, file_name);                                              \
 108store_one(_gov, file_name)
 109
 110/* create helper routines */
 111#define define_get_cpu_dbs_routines(_dbs_info)                          \
 112static struct cpu_dbs_common_info *get_cpu_cdbs(int cpu)                \
 113{                                                                       \
 114        return &per_cpu(_dbs_info, cpu).cdbs;                           \
 115}                                                                       \
 116                                                                        \
 117static void *get_cpu_dbs_info_s(int cpu)                                \
 118{                                                                       \
 119        return &per_cpu(_dbs_info, cpu);                                \
 120}
 121
 122/*
 123 * Abbreviations:
 124 * dbs: used as a shortform for demand based switching It helps to keep variable
 125 *      names smaller, simpler
 126 * cdbs: common dbs
 127 * od_*: On-demand governor
 128 * cs_*: Conservative governor
 129 */
 130
 131/* Per cpu structures */
 132struct cpu_dbs_common_info {
 133        int cpu;
 134        u64 prev_cpu_idle;
 135        u64 prev_cpu_wall;
 136        u64 prev_cpu_nice;
 137        struct cpufreq_policy *cur_policy;
 138        struct delayed_work work;
 139        /*
 140         * percpu mutex that serializes governor limit change with gov_dbs_timer
 141         * invocation. We do not want gov_dbs_timer to run when user is changing
 142         * the governor or limits.
 143         */
 144        struct mutex timer_mutex;
 145        ktime_t time_stamp;
 146};
 147
 148struct od_cpu_dbs_info_s {
 149        struct cpu_dbs_common_info cdbs;
 150        struct cpufreq_frequency_table *freq_table;
 151        unsigned int freq_lo;
 152        unsigned int freq_lo_jiffies;
 153        unsigned int freq_hi_jiffies;
 154        unsigned int rate_mult;
 155        unsigned int sample_type:1;
 156};
 157
 158struct cs_cpu_dbs_info_s {
 159        struct cpu_dbs_common_info cdbs;
 160        unsigned int down_skip;
 161        unsigned int requested_freq;
 162        unsigned int enable:1;
 163};
 164
 165/* Per policy Governors sysfs tunables */
 166struct od_dbs_tuners {
 167        unsigned int ignore_nice_load;
 168        unsigned int sampling_rate;
 169        unsigned int sampling_down_factor;
 170        unsigned int up_threshold;
 171        unsigned int powersave_bias;
 172        unsigned int io_is_busy;
 173};
 174
 175struct cs_dbs_tuners {
 176        unsigned int ignore_nice_load;
 177        unsigned int sampling_rate;
 178        unsigned int sampling_down_factor;
 179        unsigned int up_threshold;
 180        unsigned int down_threshold;
 181        unsigned int freq_step;
 182};
 183
 184/* Common Governor data across policies */
 185struct dbs_data;
 186struct common_dbs_data {
 187        /* Common across governors */
 188        #define GOV_ONDEMAND            0
 189        #define GOV_CONSERVATIVE        1
 190        int governor;
 191        struct attribute_group *attr_group_gov_sys; /* one governor - system */
 192        struct attribute_group *attr_group_gov_pol; /* one governor - policy */
 193
 194        /* Common data for platforms that don't set have_governor_per_policy */
 195        struct dbs_data *gdbs_data;
 196
 197        struct cpu_dbs_common_info *(*get_cpu_cdbs)(int cpu);
 198        void *(*get_cpu_dbs_info_s)(int cpu);
 199        void (*gov_dbs_timer)(struct work_struct *work);
 200        void (*gov_check_cpu)(int cpu, unsigned int load);
 201        int (*init)(struct dbs_data *dbs_data);
 202        void (*exit)(struct dbs_data *dbs_data);
 203
 204        /* Governor specific ops, see below */
 205        void *gov_ops;
 206};
 207
 208/* Governor Per policy data */
 209struct dbs_data {
 210        struct common_dbs_data *cdata;
 211        unsigned int min_sampling_rate;
 212        int usage_count;
 213        void *tuners;
 214
 215        /* dbs_mutex protects dbs_enable in governor start/stop */
 216        struct mutex mutex;
 217};
 218
 219/* Governor specific ops, will be passed to dbs_data->gov_ops */
 220struct od_ops {
 221        void (*powersave_bias_init_cpu)(int cpu);
 222        unsigned int (*powersave_bias_target)(struct cpufreq_policy *policy,
 223                        unsigned int freq_next, unsigned int relation);
 224        void (*freq_increase)(struct cpufreq_policy *policy, unsigned int freq);
 225};
 226
 227struct cs_ops {
 228        struct notifier_block *notifier_block;
 229};
 230
 231static inline int delay_for_sampling_rate(unsigned int sampling_rate)
 232{
 233        int delay = usecs_to_jiffies(sampling_rate);
 234
 235        /* We want all CPUs to do sampling nearly on same jiffy */
 236        if (num_online_cpus() > 1)
 237                delay -= jiffies % delay;
 238
 239        return delay;
 240}
 241
 242#define declare_show_sampling_rate_min(_gov)                            \
 243static ssize_t show_sampling_rate_min_gov_sys                           \
 244(struct kobject *kobj, struct attribute *attr, char *buf)               \
 245{                                                                       \
 246        struct dbs_data *dbs_data = _gov##_dbs_cdata.gdbs_data;         \
 247        return sprintf(buf, "%u\n", dbs_data->min_sampling_rate);       \
 248}                                                                       \
 249                                                                        \
 250static ssize_t show_sampling_rate_min_gov_pol                           \
 251(struct cpufreq_policy *policy, char *buf)                              \
 252{                                                                       \
 253        struct dbs_data *dbs_data = policy->governor_data;              \
 254        return sprintf(buf, "%u\n", dbs_data->min_sampling_rate);       \
 255}
 256
 257void dbs_check_cpu(struct dbs_data *dbs_data, int cpu);
 258bool need_load_eval(struct cpu_dbs_common_info *cdbs,
 259                unsigned int sampling_rate);
 260int cpufreq_governor_dbs(struct cpufreq_policy *policy,
 261                struct common_dbs_data *cdata, unsigned int event);
 262void gov_queue_work(struct dbs_data *dbs_data, struct cpufreq_policy *policy,
 263                unsigned int delay, bool all_cpus);
 264void od_register_powersave_bias_handler(unsigned int (*f)
 265                (struct cpufreq_policy *, unsigned int, unsigned int),
 266                unsigned int powersave_bias);
 267void od_unregister_powersave_bias_handler(void);
 268#endif /* _CPUFREQ_GOVERNOR_H */
 269
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