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 /*
  52  * Abbreviations:
  53  * dbs: used as a shortform for demand based switching It helps to keep variable
  54  *      names smaller, simpler
  55  * cdbs: common dbs
  56  * od_*: On-demand governor
  57  * cs_*: Conservative governor
  58  */
  59
  60 /* Governor demand based switching data (per-policy or global). */
  61 struct dbs_data {
  62         int usage_count;
  63         void *tuners;
  64         unsigned int min_sampling_rate;
  65         unsigned int ignore_nice_load;
  66         unsigned int sampling_rate;
  67         unsigned int sampling_down_factor;
  68         unsigned int up_threshold;
  69         unsigned int io_is_busy;
  70
  71         struct kobject kobj;
  72         struct list_head policy_dbs_list;
  73         /*
  74          * Protect concurrent updates to governor tunables from sysfs,
  75          * policy_dbs_list and usage_count.
  76          */
  77         struct mutex mutex;
  78 };
  79
  80 /* Governor's specific attributes */
  81 struct dbs_data;
  82 struct governor_attr {
  83         struct attribute attr;
  84         ssize_t (*show)(struct dbs_data *dbs_data, char *buf);
  85         ssize_t (*store)(struct dbs_data *dbs_data, const char *buf,
  86                          size_t count);
  87 };
  88
  89 #define gov_show_one(_gov, file_name)                                   \
  90 static ssize_t show_##file_name                                         \
  91 (struct dbs_data *dbs_data, char *buf)                                  \
  92 {                                                                       \
  93         struct _gov##_dbs_tuners *tuners = dbs_data->tuners;            \
  94         return sprintf(buf, "%u\n", tuners->file_name);                 \
  95 }
  96
  97 #define gov_show_one_common(file_name)                                  \
  98 static ssize_t show_##file_name                                         \
  99 (struct dbs_data *dbs_data, char *buf)                                  \
 100 {                                                                       \
 101         return sprintf(buf, "%u\n", dbs_data->file_name);               \
 102 }
 103
 104 #define gov_attr_ro(_name)                                              \
 105 static struct governor_attr _name =                                     \
 106 __ATTR(_name, 0444, show_##_name, NULL)
 107
 108 #define gov_attr_rw(_name)                                              \
 109 static struct governor_attr _name =                                     \
 110 __ATTR(_name, 0644, show_##_name, store_##_name)
 111
 112 /* Common to all CPUs of a policy */
 113 struct policy_dbs_info {
 114         struct cpufreq_policy *policy;
 115         /*
 116          * Per policy mutex that serializes load evaluation from limit-change
 117          * and work-handler.
 118          */
 119         struct mutex timer_mutex;
 120
 121         u64 last_sample_time;
 122         s64 sample_delay_ns;
 123         atomic_t work_count;
 124         struct irq_work irq_work;
 125         struct work_struct work;
 126         /* dbs_data may be shared between multiple policy objects */
 127         struct dbs_data *dbs_data;
 128         struct list_head list;
 129         /* Multiplier for increasing sample delay temporarily. */
 130         unsigned int rate_mult;
 131         /* Status indicators */
 132         bool is_shared;         /* This object is used by multiple CPUs */
 133         bool work_in_progress;  /* Work is being queued up or in progress */
 134 };
 135
 136 static inline void gov_update_sample_delay(struct policy_dbs_info *policy_dbs,
 137                                            unsigned int delay_us)
 138 {
 139         policy_dbs->sample_delay_ns = delay_us * NSEC_PER_USEC;
 140 }
 141
 142 /* Per cpu structures */
 143 struct cpu_dbs_info {
 144         u64 prev_cpu_idle;
 145         u64 prev_cpu_wall;
 146         u64 prev_cpu_nice;
 147         /*
 148          * Used to keep track of load in the previous interval. However, when
 149          * explicitly set to zero, it is used as a flag to ensure that we copy
 150          * the previous load to the current interval only once, upon the first
 151          * wake-up from idle.
 152          */
 153         unsigned int prev_load;
 154         struct update_util_data update_util;
 155         struct policy_dbs_info *policy_dbs;
 156 };
 157
 158 struct od_cpu_dbs_info_s {
 159         struct cpu_dbs_info cdbs;
 160         struct cpufreq_frequency_table *freq_table;
 161         unsigned int freq_lo;
 162         unsigned int freq_lo_delay_us;
 163         unsigned int freq_hi_delay_us;
 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 };
 177
 178 struct cs_dbs_tuners {
 179         unsigned int down_threshold;
 180         unsigned int freq_step;
 181 };
 182
 183 /* Common Governor data across policies */
 184 struct dbs_governor {
 185         struct cpufreq_governor gov;
 186         struct kobj_type kobj_type;
 187
 188         /*
 189          * Common data for platforms that don't set
 190          * CPUFREQ_HAVE_GOVERNOR_PER_POLICY
 191          */
 192         struct dbs_data *gdbs_data;
 193
 194         struct cpu_dbs_info *(*get_cpu_cdbs)(int cpu);
 195         unsigned int (*gov_dbs_timer)(struct cpufreq_policy *policy);
 196         int (*init)(struct dbs_data *dbs_data, bool notify);
 197         void (*exit)(struct dbs_data *dbs_data, bool notify);
 198         void (*start)(struct cpufreq_policy *policy);
 199 };
 200
 201 static inline struct dbs_governor *dbs_governor_of(struct cpufreq_policy *policy)
 202 {
 203         return container_of(policy->governor, struct dbs_governor, gov);
 204 }
 205
 206 /* Governor specific operations */
 207 struct od_ops {
 208         void (*powersave_bias_init_cpu)(int cpu);
 209         unsigned int (*powersave_bias_target)(struct cpufreq_policy *policy,
 210                         unsigned int freq_next, unsigned int relation);
 211 };
 212
 213 extern struct mutex dbs_data_mutex;
 214 unsigned int dbs_update(struct cpufreq_policy *policy);
 215 int cpufreq_governor_dbs(struct cpufreq_policy *policy, unsigned int event);
 216 void od_register_powersave_bias_handler(unsigned int (*f)
 217                 (struct cpufreq_policy *, unsigned int, unsigned int),
 218                 unsigned int powersave_bias);
 219 void od_unregister_powersave_bias_handler(void);
 220 ssize_t store_sampling_rate(struct dbs_data *dbs_data, const char *buf,
 221                             size_t count);
 222 #endif /* _CPUFREQ_GOVERNOR_H */