drivers/cpufreq/cpufreq_governor.h

   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/atomic.h>
  21 #include <linux/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 */
  41 enum {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)                                          \
  52 static struct global_attr _name##_gov_sys =                             \
  53 __ATTR(_name, 0444, show_##_name##_gov_sys, NULL)
  54
  55 #define gov_sys_attr_rw(_name)                                          \
  56 static 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)                                          \
  60 static struct freq_attr _name##_gov_pol =                               \
  61 __ATTR(_name, 0444, show_##_name##_gov_pol, NULL)
  62
  63 #define gov_pol_attr_rw(_name)                                          \
  64 static 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)                                       \
  77 static 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                                                                         \
  84 static 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)                                      \
  93 static 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                                                                         \
 100 static 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)                                 \
 108 show_one(_gov, file_name);                                              \
 109 store_one(_gov, file_name)
 110
 111 /* create helper routines */
 112 #define define_get_cpu_dbs_routines(_dbs_info)                          \
 113 static struct cpu_dbs_info *get_cpu_cdbs(int cpu)                       \
 114 {                                                                       \
 115         return &per_cpu(_dbs_info, cpu).cdbs;                           \
 116 }                                                                       \
 117                                                                         \
 118 static 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 /* Common to all CPUs of a policy */
 133 struct cpu_common_dbs_info {
 134         struct cpufreq_policy *policy;
 135         /*
 136          * Per policy mutex that serializes load evaluation from limit-change
 137          * and work-handler.
 138          */
 139         struct mutex timer_mutex;
 140
 141         ktime_t time_stamp;
 142         atomic_t skip_work;
 143         struct work_struct work;
 144 };
 145
 146 /* Per cpu structures */
 147 struct cpu_dbs_info {
 148         u64 prev_cpu_idle;
 149         u64 prev_cpu_wall;
 150         u64 prev_cpu_nice;
 151         /*
 152          * Used to keep track of load in the previous interval. However, when
 153          * explicitly set to zero, it is used as a flag to ensure that we copy
 154          * the previous load to the current interval only once, upon the first
 155          * wake-up from idle.
 156          */
 157         unsigned int prev_load;
 158         struct timer_list timer;
 159         struct cpu_common_dbs_info *shared;
 160 };
 161
 162 struct od_cpu_dbs_info_s {
 163         struct cpu_dbs_info cdbs;
 164         struct cpufreq_frequency_table *freq_table;
 165         unsigned int freq_lo;
 166         unsigned int freq_lo_jiffies;
 167         unsigned int freq_hi_jiffies;
 168         unsigned int rate_mult;
 169         unsigned int sample_type:1;
 170 };
 171
 172 struct cs_cpu_dbs_info_s {
 173         struct cpu_dbs_info cdbs;
 174         unsigned int down_skip;
 175         unsigned int requested_freq;
 176 };
 177
 178 /* Per policy Governors sysfs tunables */
 179 struct od_dbs_tuners {
 180         unsigned int ignore_nice_load;
 181         unsigned int sampling_rate;
 182         unsigned int sampling_down_factor;
 183         unsigned int up_threshold;
 184         unsigned int powersave_bias;
 185         unsigned int io_is_busy;
 186 };
 187
 188 struct cs_dbs_tuners {
 189         unsigned int ignore_nice_load;
 190         unsigned int sampling_rate;
 191         unsigned int sampling_down_factor;
 192         unsigned int up_threshold;
 193         unsigned int down_threshold;
 194         unsigned int freq_step;
 195 };
 196
 197 /* Common Governor data across policies */
 198 struct dbs_data;
 199 struct common_dbs_data {
 200         /* Common across governors */
 201         #define GOV_ONDEMAND            0
 202         #define GOV_CONSERVATIVE        1
 203         int governor;
 204         struct attribute_group *attr_group_gov_sys; /* one governor - system */
 205         struct attribute_group *attr_group_gov_pol; /* one governor - policy */
 206
 207         /*
 208          * Common data for platforms that don't set
 209          * CPUFREQ_HAVE_GOVERNOR_PER_POLICY
 210          */
 211         struct dbs_data *gdbs_data;
 212
 213         struct cpu_dbs_info *(*get_cpu_cdbs)(int cpu);
 214         void *(*get_cpu_dbs_info_s)(int cpu);
 215         unsigned int (*gov_dbs_timer)(struct cpufreq_policy *policy,
 216                                       bool modify_all);
 217         void (*gov_check_cpu)(int cpu, unsigned int load);
 218         int (*init)(struct dbs_data *dbs_data, bool notify);
 219         void (*exit)(struct dbs_data *dbs_data, bool notify);
 220
 221         /* Governor specific ops, see below */
 222         void *gov_ops;
 223
 224         /*
 225          * Protects governor's data (struct dbs_data and struct common_dbs_data)
 226          */
 227         struct mutex mutex;
 228 };
 229
 230 /* Governor Per policy data */
 231 struct dbs_data {
 232         struct common_dbs_data *cdata;
 233         unsigned int min_sampling_rate;
 234         int usage_count;
 235         void *tuners;
 236 };
 237
 238 /* Governor specific ops, will be passed to dbs_data->gov_ops */
 239 struct od_ops {
 240         void (*powersave_bias_init_cpu)(int cpu);
 241         unsigned int (*powersave_bias_target)(struct cpufreq_policy *policy,
 242                         unsigned int freq_next, unsigned int relation);
 243         void (*freq_increase)(struct cpufreq_policy *policy, unsigned int freq);
 244 };
 245
 246 static inline int delay_for_sampling_rate(unsigned int sampling_rate)
 247 {
 248         int delay = usecs_to_jiffies(sampling_rate);
 249
 250         /* We want all CPUs to do sampling nearly on same jiffy */
 251         if (num_online_cpus() > 1)
 252                 delay -= jiffies % delay;
 253
 254         return delay;
 255 }
 256
 257 #define declare_show_sampling_rate_min(_gov)                            \
 258 static ssize_t show_sampling_rate_min_gov_sys                           \
 259 (struct kobject *kobj, struct attribute *attr, char *buf)               \
 260 {                                                                       \
 261         struct dbs_data *dbs_data = _gov##_dbs_cdata.gdbs_data;         \
 262         return sprintf(buf, "%u\n", dbs_data->min_sampling_rate);       \
 263 }                                                                       \
 264                                                                         \
 265 static ssize_t show_sampling_rate_min_gov_pol                           \
 266 (struct cpufreq_policy *policy, char *buf)                              \
 267 {                                                                       \
 268         struct dbs_data *dbs_data = policy->governor_data;              \
 269         return sprintf(buf, "%u\n", dbs_data->min_sampling_rate);       \
 270 }
 271
 272 extern struct mutex cpufreq_governor_lock;
 273
 274 void gov_add_timers(struct cpufreq_policy *policy, unsigned int delay);
 275 void gov_cancel_work(struct cpu_common_dbs_info *shared);
 276 void dbs_check_cpu(struct dbs_data *dbs_data, int cpu);
 277 int cpufreq_governor_dbs(struct cpufreq_policy *policy,
 278                 struct common_dbs_data *cdata, unsigned int event);
 279 void od_register_powersave_bias_handler(unsigned int (*f)
 280                 (struct cpufreq_policy *, unsigned int, unsigned int),
 281                 unsigned int powersave_bias);
 282 void od_unregister_powersave_bias_handler(void);
 283 #endif /* _CPUFREQ_GOVERNOR_H */