LXR linux/drivers/cpufreq/cpufreq

   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/sched/cpufreq.h>
  22#include <linux/kernel_stat.h>
  23#include <linux/module.h>
  24#include <linux/mutex.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 (micro seconds).
  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        /*
 139         * Used to keep track of load in the previous interval. However, when
 140         * explicitly set to zero, it is used as a flag to ensure that we copy
 141         * the previous load to the current interval only once, upon the first
 142         * wake-up from idle.
 143         */
 144        unsigned int prev_load;
 145        struct cpufreq_policy *cur_policy;
 146        struct delayed_work work;
 147        /*
 148         * percpu mutex that serializes governor limit change with gov_dbs_timer
 149         * invocation. We do not want gov_dbs_timer to run when user is changing
 150         * the governor or limits.
 151         */
 152        struct mutex timer_mutex;
 153        ktime_t time_stamp;
 154};
 155
 156struct od_cpu_dbs_info_s {
 157        struct cpu_dbs_common_info cdbs;
 158        struct cpufreq_frequency_table *freq_table;
 159        unsigned int freq_lo;
 160        unsigned int freq_lo_jiffies;
 161        unsigned int freq_hi_jiffies;
 162        unsigned int rate_mult;
 163        unsigned int sample_type:1;
 164};
 165
 166struct cs_cpu_dbs_info_s {
 167        struct cpu_dbs_common_info cdbs;
 168        unsigned int down_skip;
 169        unsigned int requested_freq;
 170        unsigned int enable:1;
 171};
 172
 173/* Per policy Governors sysfs tunables */
 174struct od_dbs_tuners {
 175        unsigned int ignore_nice_load;
 176        unsigned int sampling_rate;
 177        unsigned int sampling_down_factor;
 178        unsigned int up_threshold;
 179        unsigned int powersave_bias;
 180        unsigned int io_is_busy;
 181};
 182
 183struct cs_dbs_tuners {
 184        unsigned int ignore_nice_load;
 185        unsigned int sampling_rate;
 186        unsigned int sampling_down_factor;
 187        unsigned int up_threshold;
 188        unsigned int down_threshold;
 189        unsigned int freq_step;
 190};
 191
 192/* Common Governor data across policies */
 193struct dbs_data;
 194struct common_dbs_data {
 195        /* Common across governors */
 196        #define GOV_ONDEMAND            0
 197        #define GOV_CONSERVATIVE        1
 198        int governor;
 199        struct attribute_group *attr_group_gov_sys; /* one governor - system */
 200        struct attribute_group *attr_group_gov_pol; /* one governor - policy */
 201
 202        /*
 203         * Common data for platforms that don't set
 204         * CPUFREQ_HAVE_GOVERNOR_PER_POLICY
 205         */
 206        struct dbs_data *gdbs_data;
 207
 208        struct cpu_dbs_common_info *(*get_cpu_cdbs)(int cpu);
 209        void *(*get_cpu_dbs_info_s)(int cpu);
 210        void (*gov_dbs_timer)(struct work_struct *work);
 211        void (*gov_check_cpu)(int cpu, unsigned int load);
 212        int (*init)(struct dbs_data *dbs_data, bool notify);
 213        void (*exit)(struct dbs_data *dbs_data, bool notify);
 214
 215        /* Governor specific ops, see below */
 216        void *gov_ops;
 217
 218        /*
 219         * Protects governor's data (struct dbs_data and struct common_dbs_data)
 220         */
 221        struct mutex mutex;
 222};
 223
 224/* Governor Per policy data */
 225struct dbs_data {
 226        struct common_dbs_data *cdata;
 227        unsigned int min_sampling_rate;
 228        int usage_count;
 229        void *tuners;
 230};
 231
 232/* Governor specific ops, will be passed to dbs_data->gov_ops */
 233struct od_ops {
 234        void (*powersave_bias_init_cpu)(int cpu);
 235        unsigned int (*powersave_bias_target)(struct cpufreq_policy *policy,
 236                        unsigned int freq_next, unsigned int relation);
 237        void (*freq_increase)(struct cpufreq_policy *policy, unsigned int freq);
 238};
 239
 240static inline int delay_for_sampling_rate(unsigned int sampling_rate)
 241{
 242        int delay = usecs_to_jiffies(sampling_rate);
 243
 244        /* We want all CPUs to do sampling nearly on same jiffy */
 245        if (num_online_cpus() > 1)
 246                delay -= jiffies % delay;
 247
 248        return delay;
 249}
 250
 251#define declare_show_sampling_rate_min(_gov)                            \
 252static ssize_t show_sampling_rate_min_gov_sys                           \
 253(struct kobject *kobj, struct attribute *attr, char *buf)               \
 254{                                                                       \
 255        struct dbs_data *dbs_data = _gov##_dbs_cdata.gdbs_data;         \
 256        return sprintf(buf, "%u\n", dbs_data->min_sampling_rate);       \
 257}                                                                       \
 258                                                                        \
 259static ssize_t show_sampling_rate_min_gov_pol                           \
 260(struct cpufreq_policy *policy, char *buf)                              \
 261{                                                                       \
 262        struct dbs_data *dbs_data = policy->governor_data;              \
 263        return sprintf(buf, "%u\n", dbs_data->min_sampling_rate);       \
 264}
 265
 266extern struct mutex cpufreq_governor_lock;
 267
 268void dbs_check_cpu(struct dbs_data *dbs_data, int cpu);
 269bool need_load_eval(struct cpu_dbs_common_info *cdbs,
 270                unsigned int sampling_rate);
 271int cpufreq_governor_dbs(struct cpufreq_policy *policy,
 272                struct common_dbs_data *cdata, unsigned int event);
 273void gov_queue_work(struct dbs_data *dbs_data, struct cpufreq_policy *policy,
 274                unsigned int delay, bool all_cpus);
 275void od_register_powersave_bias_handler(unsigned int (*f)
 276                (struct cpufreq_policy *, unsigned int, unsigned int),
 277                unsigned int powersave_bias);
 278void od_unregister_powersave_bias_handler(void);
 279#endif /* _CPUFREQ_GOVERNOR_H */
 280