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/irq_work.h>
  22 #include <linux/cpufreq.h>
  23 #include <linux/kernel_stat.h>
  24 #include <linux/module.h>
  25 #include <linux/mutex.h>
  26
  27 /*
  28  * The polling frequency depends on the capability of the processor. Default
  29  * polling frequency is 1000 times the transition latency of the processor. The
  30  * governor will work on any processor with transition latency <= 10ms, using
  31  * appropriate sampling rate.
  32  *
  33  * For CPUs with transition latency > 10ms (mostly drivers with CPUFREQ_ETERNAL)
  34  * this governor will not work. All times here are in us (micro seconds).
  35  */
  36 #define MIN_SAMPLING_RATE_RATIO                 (2)
  37 #define LATENCY_MULTIPLIER                      (1000)
  38 #define MIN_LATENCY_MULTIPLIER                  (20)
  39 #define TRANSITION_LATENCY_LIMIT                (10 * 1000 * 1000)
  40
  41 /* Ondemand Sampling types */
  42 enum {OD_NORMAL_SAMPLE, OD_SUB_SAMPLE};
  43
  44 /*
  45  * Macro for creating governors sysfs routines
  46  *
  47  * - gov_sys: One governor instance per whole system
  48  * - gov_pol: One governor instance per policy
  49  */
  50
  51 /* Create attributes */
  52 #define gov_sys_attr_ro(_name)                                          \
  53 static struct global_attr _name##_gov_sys =                             \
  54 __ATTR(_name, 0444, show_##_name##_gov_sys, NULL)
  55
  56 #define gov_sys_attr_rw(_name)                                          \
  57 static struct global_attr _name##_gov_sys =                             \
  58 __ATTR(_name, 0644, show_##_name##_gov_sys, store_##_name##_gov_sys)
  59
  60 #define gov_pol_attr_ro(_name)                                          \
  61 static struct freq_attr _name##_gov_pol =                               \
  62 __ATTR(_name, 0444, show_##_name##_gov_pol, NULL)
  63
  64 #define gov_pol_attr_rw(_name)                                          \
  65 static struct freq_attr _name##_gov_pol =                               \
  66 __ATTR(_name, 0644, show_##_name##_gov_pol, store_##_name##_gov_pol)
  67
  68 #define gov_sys_pol_attr_rw(_name)                                      \
  69         gov_sys_attr_rw(_name);                                         \
  70         gov_pol_attr_rw(_name)
  71
  72 #define gov_sys_pol_attr_ro(_name)                                      \
  73         gov_sys_attr_ro(_name);                                         \
  74         gov_pol_attr_ro(_name)
  75
  76 /* Create show/store routines */
  77 #define show_one(_gov, file_name)                                       \
  78 static ssize_t show_##file_name##_gov_sys                               \
  79 (struct kobject *kobj, struct attribute *attr, char *buf)               \
  80 {                                                                       \
  81         struct _gov##_dbs_tuners *tuners = _gov##_dbs_gov.gdbs_data->tuners; \
  82         return sprintf(buf, "%u\n", tuners->file_name);                 \
  83 }                                                                       \
  84                                                                         \
  85 static ssize_t show_##file_name##_gov_pol                               \
  86 (struct cpufreq_policy *policy, char *buf)                              \
  87 {                                                                       \
  88         struct policy_dbs_info *policy_dbs = policy->governor_data;     \
  89         struct dbs_data *dbs_data = policy_dbs->dbs_data;               \
  90         struct _gov##_dbs_tuners *tuners = dbs_data->tuners;            \
  91         return sprintf(buf, "%u\n", tuners->file_name);                 \
  92 }
  93
  94 #define store_one(_gov, file_name)                                      \
  95 static ssize_t store_##file_name##_gov_sys                              \
  96 (struct kobject *kobj, struct attribute *attr, const char *buf, size_t count) \
  97 {                                                                       \
  98         struct dbs_data *dbs_data = _gov##_dbs_gov.gdbs_data;           \
  99         return store_##file_name(dbs_data, buf, count);                 \
 100 }                                                                       \
 101                                                                         \
 102 static ssize_t store_##file_name##_gov_pol                              \
 103 (struct cpufreq_policy *policy, const char *buf, size_t count)          \
 104 {                                                                       \
 105         struct policy_dbs_info *policy_dbs = policy->governor_data;     \
 106         return store_##file_name(policy_dbs->dbs_data, buf, count);                     \
 107 }
 108
 109 #define show_store_one(_gov, file_name)                                 \
 110 show_one(_gov, file_name);                                              \
 111 store_one(_gov, file_name)
 112
 113 #define show_one_common(_gov, file_name)                                \
 114 static ssize_t show_##file_name##_gov_sys                               \
 115 (struct kobject *kobj, struct attribute *attr, char *buf)               \
 116 {                                                                       \
 117         struct dbs_data *dbs_data = _gov##_dbs_gov.gdbs_data;           \
 118         return sprintf(buf, "%u\n", dbs_data->file_name);               \
 119 }                                                                       \
 120                                                                         \
 121 static ssize_t show_##file_name##_gov_pol                               \
 122 (struct cpufreq_policy *policy, char *buf)                              \
 123 {                                                                       \
 124         struct policy_dbs_info *policy_dbs = policy->governor_data;     \
 125         struct dbs_data *dbs_data = policy_dbs->dbs_data;               \
 126         return sprintf(buf, "%u\n", dbs_data->file_name);               \
 127 }
 128
 129 #define show_store_one_common(_gov, file_name)                          \
 130 show_one_common(_gov, file_name);                                       \
 131 store_one(_gov, file_name)
 132
 133 /* create helper routines */
 134 #define define_get_cpu_dbs_routines(_dbs_info)                          \
 135 static struct cpu_dbs_info *get_cpu_cdbs(int cpu)                       \
 136 {                                                                       \
 137         return &per_cpu(_dbs_info, cpu).cdbs;                           \
 138 }                                                                       \
 139                                                                         \
 140 static void *get_cpu_dbs_info_s(int cpu)                                \
 141 {                                                                       \
 142         return &per_cpu(_dbs_info, cpu);                                \
 143 }
 144
 145 /*
 146  * Abbreviations:
 147  * dbs: used as a shortform for demand based switching It helps to keep variable
 148  *      names smaller, simpler
 149  * cdbs: common dbs
 150  * od_*: On-demand governor
 151  * cs_*: Conservative governor
 152  */
 153
 154 /* Governor demand based switching data (per-policy or global). */
 155 struct dbs_data {
 156         int usage_count;
 157         void *tuners;
 158         unsigned int min_sampling_rate;
 159         unsigned int ignore_nice_load;
 160         unsigned int sampling_rate;
 161         unsigned int sampling_down_factor;
 162         unsigned int up_threshold;
 163 };
 164
 165 /* Common to all CPUs of a policy */
 166 struct policy_dbs_info {
 167         struct cpufreq_policy *policy;
 168         /*
 169          * Per policy mutex that serializes load evaluation from limit-change
 170          * and work-handler.
 171          */
 172         struct mutex timer_mutex;
 173
 174         u64 last_sample_time;
 175         s64 sample_delay_ns;
 176         atomic_t work_count;
 177         struct irq_work irq_work;
 178         struct work_struct work;
 179         /* dbs_data may be shared between multiple policy objects */
 180         struct dbs_data *dbs_data;
 181 };
 182
 183 static inline void gov_update_sample_delay(struct policy_dbs_info *policy_dbs,
 184                                            unsigned int delay_us)
 185 {
 186         policy_dbs->sample_delay_ns = delay_us * NSEC_PER_USEC;
 187 }
 188
 189 /* Per cpu structures */
 190 struct cpu_dbs_info {
 191         u64 prev_cpu_idle;
 192         u64 prev_cpu_wall;
 193         u64 prev_cpu_nice;
 194         /*
 195          * Used to keep track of load in the previous interval. However, when
 196          * explicitly set to zero, it is used as a flag to ensure that we copy
 197          * the previous load to the current interval only once, upon the first
 198          * wake-up from idle.
 199          */
 200         unsigned int prev_load;
 201         struct update_util_data update_util;
 202         struct policy_dbs_info *policy_dbs;
 203 };
 204
 205 struct od_cpu_dbs_info_s {
 206         struct cpu_dbs_info cdbs;
 207         struct cpufreq_frequency_table *freq_table;
 208         unsigned int freq_lo;
 209         unsigned int freq_lo_jiffies;
 210         unsigned int freq_hi_jiffies;
 211         unsigned int rate_mult;
 212         unsigned int sample_type:1;
 213 };
 214
 215 struct cs_cpu_dbs_info_s {
 216         struct cpu_dbs_info cdbs;
 217         unsigned int down_skip;
 218         unsigned int requested_freq;
 219 };
 220
 221 /* Per policy Governors sysfs tunables */
 222 struct od_dbs_tuners {
 223         unsigned int powersave_bias;
 224         unsigned int io_is_busy;
 225 };
 226
 227 struct cs_dbs_tuners {
 228         unsigned int down_threshold;
 229         unsigned int freq_step;
 230 };
 231
 232 /* Common Governor data across policies */
 233 struct dbs_governor {
 234         struct cpufreq_governor gov;
 235
 236         #define GOV_ONDEMAND            0
 237         #define GOV_CONSERVATIVE        1
 238         int governor;
 239         struct attribute_group *attr_group_gov_sys; /* one governor - system */
 240         struct attribute_group *attr_group_gov_pol; /* one governor - policy */
 241
 242         /*
 243          * Common data for platforms that don't set
 244          * CPUFREQ_HAVE_GOVERNOR_PER_POLICY
 245          */
 246         struct dbs_data *gdbs_data;
 247
 248         struct cpu_dbs_info *(*get_cpu_cdbs)(int cpu);
 249         void *(*get_cpu_dbs_info_s)(int cpu);
 250         unsigned int (*gov_dbs_timer)(struct cpufreq_policy *policy);
 251         void (*gov_check_cpu)(int cpu, unsigned int load);
 252         int (*init)(struct dbs_data *dbs_data, bool notify);
 253         void (*exit)(struct dbs_data *dbs_data, bool notify);
 254
 255         /* Governor specific ops, see below */
 256         void *gov_ops;
 257 };
 258
 259 static inline struct dbs_governor *dbs_governor_of(struct cpufreq_policy *policy)
 260 {
 261         return container_of(policy->governor, struct dbs_governor, gov);
 262 }
 263
 264 /* Governor specific ops, will be passed to dbs_data->gov_ops */
 265 struct od_ops {
 266         void (*powersave_bias_init_cpu)(int cpu);
 267         unsigned int (*powersave_bias_target)(struct cpufreq_policy *policy,
 268                         unsigned int freq_next, unsigned int relation);
 269         void (*freq_increase)(struct cpufreq_policy *policy, unsigned int freq);
 270 };
 271
 272 static inline int delay_for_sampling_rate(unsigned int sampling_rate)
 273 {
 274         int delay = usecs_to_jiffies(sampling_rate);
 275
 276         /* We want all CPUs to do sampling nearly on same jiffy */
 277         if (num_online_cpus() > 1)
 278                 delay -= jiffies % delay;
 279
 280         return delay;
 281 }
 282
 283 extern struct mutex dbs_data_mutex;
 284 extern struct mutex cpufreq_governor_lock;
 285 void dbs_check_cpu(struct cpufreq_policy *policy);
 286 int cpufreq_governor_dbs(struct cpufreq_policy *policy, unsigned int event);
 287 void od_register_powersave_bias_handler(unsigned int (*f)
 288                 (struct cpufreq_policy *, unsigned int, unsigned int),
 289                 unsigned int powersave_bias);
 290 void od_unregister_powersave_bias_handler(void);
 291 #endif /* _CPUFREQ_GOVERNOR_H */