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 /* create helper routines */
  45 #define define_get_cpu_dbs_routines(_dbs_info)                          \
  46 static struct cpu_dbs_info *get_cpu_cdbs(int cpu)                       \
  47 {                                                                       \
  48         return &per_cpu(_dbs_info, cpu).cdbs;                           \
  49 }                                                                       \
  50                                                                         \
  51 static void *get_cpu_dbs_info_s(int cpu)                                \
  52 {                                                                       \
  53         return &per_cpu(_dbs_info, cpu);                                \
  54 }
  55
  56 /*
  57  * Abbreviations:
  58  * dbs: used as a shortform for demand based switching It helps to keep variable
  59  *      names smaller, simpler
  60  * cdbs: common dbs
  61  * od_*: On-demand governor
  62  * cs_*: Conservative governor
  63  */
  64
  65 /* Governor demand based switching data (per-policy or global). */
  66 struct dbs_data {
  67         int usage_count;
  68         void *tuners;
  69         unsigned int min_sampling_rate;
  70         unsigned int ignore_nice_load;
  71         unsigned int sampling_rate;
  72         unsigned int sampling_down_factor;
  73         unsigned int up_threshold;
  74
  75         struct kobject kobj;
  76         struct list_head policy_dbs_list;
  77         /*
  78          * Protect concurrent updates to governor tunables from sysfs,
  79          * policy_dbs_list and usage_count.
  80          */
  81         struct mutex mutex;
  82 };
  83
  84 /* Governor's specific attributes */
  85 struct dbs_data;
  86 struct governor_attr {
  87         struct attribute attr;
  88         ssize_t (*show)(struct dbs_data *dbs_data, char *buf);
  89         ssize_t (*store)(struct dbs_data *dbs_data, const char *buf,
  90                          size_t count);
  91 };
  92
  93 #define gov_show_one(_gov, file_name)                                   \
  94 static ssize_t show_##file_name                                         \
  95 (struct dbs_data *dbs_data, char *buf)                                  \
  96 {                                                                       \
  97         struct _gov##_dbs_tuners *tuners = dbs_data->tuners;            \
  98         return sprintf(buf, "%u\n", tuners->file_name);                 \
  99 }
 100
 101 #define gov_show_one_common(file_name)                                  \
 102 static ssize_t show_##file_name                                         \
 103 (struct dbs_data *dbs_data, char *buf)                                  \
 104 {                                                                       \
 105         return sprintf(buf, "%u\n", dbs_data->file_name);               \
 106 }
 107
 108 #define gov_attr_ro(_name)                                              \
 109 static struct governor_attr _name =                                     \
 110 __ATTR(_name, 0444, show_##_name, NULL)
 111
 112 #define gov_attr_rw(_name)                                              \
 113 static struct governor_attr _name =                                     \
 114 __ATTR(_name, 0644, show_##_name, store_##_name)
 115
 116 /* Common to all CPUs of a policy */
 117 struct policy_dbs_info {
 118         struct cpufreq_policy *policy;
 119         /*
 120          * Per policy mutex that serializes load evaluation from limit-change
 121          * and work-handler.
 122          */
 123         struct mutex timer_mutex;
 124
 125         u64 last_sample_time;
 126         s64 sample_delay_ns;
 127         atomic_t work_count;
 128         struct irq_work irq_work;
 129         struct work_struct work;
 130         /* dbs_data may be shared between multiple policy objects */
 131         struct dbs_data *dbs_data;
 132         struct list_head list;
 133 };
 134
 135 static inline void gov_update_sample_delay(struct policy_dbs_info *policy_dbs,
 136                                            unsigned int delay_us)
 137 {
 138         policy_dbs->sample_delay_ns = delay_us * NSEC_PER_USEC;
 139 }
 140
 141 /* Per cpu structures */
 142 struct cpu_dbs_info {
 143         u64 prev_cpu_idle;
 144         u64 prev_cpu_wall;
 145         u64 prev_cpu_nice;
 146         /*
 147          * Used to keep track of load in the previous interval. However, when
 148          * explicitly set to zero, it is used as a flag to ensure that we copy
 149          * the previous load to the current interval only once, upon the first
 150          * wake-up from idle.
 151          */
 152         unsigned int prev_load;
 153         struct update_util_data update_util;
 154         struct policy_dbs_info *policy_dbs;
 155 };
 156
 157 struct od_cpu_dbs_info_s {
 158         struct cpu_dbs_info cdbs;
 159         struct cpufreq_frequency_table *freq_table;
 160         unsigned int freq_lo;
 161         unsigned int freq_lo_jiffies;
 162         unsigned int freq_hi_jiffies;
 163         unsigned int rate_mult;
 164         unsigned int sample_type:1;
 165 };
 166
 167 struct cs_cpu_dbs_info_s {
 168         struct cpu_dbs_info cdbs;
 169         unsigned int down_skip;
 170         unsigned int requested_freq;
 171 };
 172
 173 /* Per policy Governors sysfs tunables */
 174 struct od_dbs_tuners {
 175         unsigned int powersave_bias;
 176         unsigned int io_is_busy;
 177 };
 178
 179 struct cs_dbs_tuners {
 180         unsigned int down_threshold;
 181         unsigned int freq_step;
 182 };
 183
 184 /* Common Governor data across policies */
 185 struct dbs_governor {
 186         struct cpufreq_governor gov;
 187
 188         #define GOV_ONDEMAND            0
 189         #define GOV_CONSERVATIVE        1
 190         int governor;
 191         struct kobj_type kobj_type;
 192
 193         /*
 194          * Common data for platforms that don't set
 195          * CPUFREQ_HAVE_GOVERNOR_PER_POLICY
 196          */
 197         struct dbs_data *gdbs_data;
 198
 199         struct cpu_dbs_info *(*get_cpu_cdbs)(int cpu);
 200         void *(*get_cpu_dbs_info_s)(int cpu);
 201         unsigned int (*gov_dbs_timer)(struct cpufreq_policy *policy);
 202         void (*gov_check_cpu)(int cpu, unsigned int load);
 203         int (*init)(struct dbs_data *dbs_data, bool notify);
 204         void (*exit)(struct dbs_data *dbs_data, bool notify);
 205
 206         /* Governor specific ops, see below */
 207         void *gov_ops;
 208 };
 209
 210 static inline struct dbs_governor *dbs_governor_of(struct cpufreq_policy *policy)
 211 {
 212         return container_of(policy->governor, struct dbs_governor, gov);
 213 }
 214
 215 /* Governor specific ops, will be passed to dbs_data->gov_ops */
 216 struct od_ops {
 217         void (*powersave_bias_init_cpu)(int cpu);
 218         unsigned int (*powersave_bias_target)(struct cpufreq_policy *policy,
 219                         unsigned int freq_next, unsigned int relation);
 220         void (*freq_increase)(struct cpufreq_policy *policy, unsigned int freq);
 221 };
 222
 223 static inline int delay_for_sampling_rate(unsigned int sampling_rate)
 224 {
 225         int delay = usecs_to_jiffies(sampling_rate);
 226
 227         /* We want all CPUs to do sampling nearly on same jiffy */
 228         if (num_online_cpus() > 1)
 229                 delay -= jiffies % delay;
 230
 231         return delay;
 232 }
 233
 234 extern struct mutex dbs_data_mutex;
 235 void dbs_check_cpu(struct cpufreq_policy *policy);
 236 int cpufreq_governor_dbs(struct cpufreq_policy *policy, unsigned int event);
 237 void od_register_powersave_bias_handler(unsigned int (*f)
 238                 (struct cpufreq_policy *, unsigned int, unsigned int),
 239                 unsigned int powersave_bias);
 240 void od_unregister_powersave_bias_handler(void);
 241 ssize_t store_sampling_rate(struct dbs_data *dbs_data, const char *buf,
 242                             size_t count);
 243 #endif /* _CPUFREQ_GOVERNOR_H */