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 /* Ondemand Sampling types */
  28 enum {OD_NORMAL_SAMPLE, OD_SUB_SAMPLE};
  29
  30 /*
  31  * Abbreviations:
  32  * dbs: used as a shortform for demand based switching It helps to keep variable
  33  *      names smaller, simpler
  34  * cdbs: common dbs
  35  * od_*: On-demand governor
  36  * cs_*: Conservative governor
  37  */
  38
  39 /* Governor demand based switching data (per-policy or global). */
  40 struct dbs_data {
  41         struct gov_attr_set attr_set;
  42         void *tuners;
  43         unsigned int min_sampling_rate;
  44         unsigned int ignore_nice_load;
  45         unsigned int sampling_rate;
  46         unsigned int sampling_down_factor;
  47         unsigned int up_threshold;
  48         unsigned int io_is_busy;
  49 };
  50
  51 static inline struct dbs_data *to_dbs_data(struct gov_attr_set *attr_set)
  52 {
  53         return container_of(attr_set, struct dbs_data, attr_set);
  54 }
  55
  56 #define gov_show_one(_gov, file_name)                                   \
  57 static ssize_t show_##file_name                                         \
  58 (struct gov_attr_set *attr_set, char *buf)                              \
  59 {                                                                       \
  60         struct dbs_data *dbs_data = to_dbs_data(attr_set);              \
  61         struct _gov##_dbs_tuners *tuners = dbs_data->tuners;            \
  62         return sprintf(buf, "%u\n", tuners->file_name);                 \
  63 }
  64
  65 #define gov_show_one_common(file_name)                                  \
  66 static ssize_t show_##file_name                                         \
  67 (struct gov_attr_set *attr_set, char *buf)                              \
  68 {                                                                       \
  69         struct dbs_data *dbs_data = to_dbs_data(attr_set);              \
  70         return sprintf(buf, "%u\n", dbs_data->file_name);               \
  71 }
  72
  73 #define gov_attr_ro(_name)                                              \
  74 static struct governor_attr _name =                                     \
  75 __ATTR(_name, 0444, show_##_name, NULL)
  76
  77 #define gov_attr_rw(_name)                                              \
  78 static struct governor_attr _name =                                     \
  79 __ATTR(_name, 0644, show_##_name, store_##_name)
  80
  81 /* Common to all CPUs of a policy */
  82 struct policy_dbs_info {
  83         struct cpufreq_policy *policy;
  84         /*
  85          * Per policy mutex that serializes load evaluation from limit-change
  86          * and work-handler.
  87          */
  88         struct mutex update_mutex;
  89
  90         u64 last_sample_time;
  91         s64 sample_delay_ns;
  92         atomic_t work_count;
  93         struct irq_work irq_work;
  94         struct work_struct work;
  95         /* dbs_data may be shared between multiple policy objects */
  96         struct dbs_data *dbs_data;
  97         struct list_head list;
  98         /* Multiplier for increasing sample delay temporarily. */
  99         unsigned int rate_mult;
 100         unsigned int idle_periods;      /* For conservative */
 101         /* Status indicators */
 102         bool is_shared;         /* This object is used by multiple CPUs */
 103         bool work_in_progress;  /* Work is being queued up or in progress */
 104 };
 105
 106 static inline void gov_update_sample_delay(struct policy_dbs_info *policy_dbs,
 107                                            unsigned int delay_us)
 108 {
 109         policy_dbs->sample_delay_ns = delay_us * NSEC_PER_USEC;
 110 }
 111
 112 /* Per cpu structures */
 113 struct cpu_dbs_info {
 114         u64 prev_cpu_idle;
 115         u64 prev_update_time;
 116         u64 prev_cpu_nice;
 117         /*
 118          * Used to keep track of load in the previous interval. However, when
 119          * explicitly set to zero, it is used as a flag to ensure that we copy
 120          * the previous load to the current interval only once, upon the first
 121          * wake-up from idle.
 122          */
 123         unsigned int prev_load;
 124         struct update_util_data update_util;
 125         struct policy_dbs_info *policy_dbs;
 126 };
 127
 128 /* Common Governor data across policies */
 129 struct dbs_governor {
 130         struct cpufreq_governor gov;
 131         struct kobj_type kobj_type;
 132
 133         /*
 134          * Common data for platforms that don't set
 135          * CPUFREQ_HAVE_GOVERNOR_PER_POLICY
 136          */
 137         struct dbs_data *gdbs_data;
 138
 139         unsigned int (*gov_dbs_update)(struct cpufreq_policy *policy);
 140         struct policy_dbs_info *(*alloc)(void);
 141         void (*free)(struct policy_dbs_info *policy_dbs);
 142         int (*init)(struct dbs_data *dbs_data);
 143         void (*exit)(struct dbs_data *dbs_data);
 144         void (*start)(struct cpufreq_policy *policy);
 145 };
 146
 147 static inline struct dbs_governor *dbs_governor_of(struct cpufreq_policy *policy)
 148 {
 149         return container_of(policy->governor, struct dbs_governor, gov);
 150 }
 151
 152 /* Governor callback routines */
 153 int cpufreq_dbs_governor_init(struct cpufreq_policy *policy);
 154 void cpufreq_dbs_governor_exit(struct cpufreq_policy *policy);
 155 int cpufreq_dbs_governor_start(struct cpufreq_policy *policy);
 156 void cpufreq_dbs_governor_stop(struct cpufreq_policy *policy);
 157 void cpufreq_dbs_governor_limits(struct cpufreq_policy *policy);
 158
 159 #define CPUFREQ_DBS_GOVERNOR_INITIALIZER(_name_)                        \
 160         {                                                               \
 161                 .name = _name_,                                         \
 162                 .max_transition_latency = TRANSITION_LATENCY_LIMIT,     \
 163                 .owner = THIS_MODULE,                                   \
 164                 .init = cpufreq_dbs_governor_init,                      \
 165                 .exit = cpufreq_dbs_governor_exit,                      \
 166                 .start = cpufreq_dbs_governor_start,                    \
 167                 .stop = cpufreq_dbs_governor_stop,                      \
 168                 .limits = cpufreq_dbs_governor_limits,                  \
 169         }
 170
 171 /* Governor specific operations */
 172 struct od_ops {
 173         unsigned int (*powersave_bias_target)(struct cpufreq_policy *policy,
 174                         unsigned int freq_next, unsigned int relation);
 175 };
 176
 177 unsigned int dbs_update(struct cpufreq_policy *policy);
 178 void od_register_powersave_bias_handler(unsigned int (*f)
 179                 (struct cpufreq_policy *, unsigned int, unsigned int),
 180                 unsigned int powersave_bias);
 181 void od_unregister_powersave_bias_handler(void);
 182 ssize_t store_sampling_rate(struct gov_attr_set *attr_set, const char *buf,
 183                             size_t count);
 184 void gov_update_cpu_data(struct dbs_data *dbs_data);
 185 #endif /* _CPUFREQ_GOVERNOR_H */