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