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