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 struct gov_attr_set {
  45         struct kobject kobj;
  46         struct list_head policy_list;
  47         struct mutex update_lock;
  48         int usage_count;
  49 };
  50
  51 extern const struct sysfs_ops governor_sysfs_ops;
  52
  53 void gov_attr_set_init(struct gov_attr_set *attr_set, struct list_head *list_node);
  54 void gov_attr_set_get(struct gov_attr_set *attr_set, struct list_head *list_node);
  55 unsigned int gov_attr_set_put(struct gov_attr_set *attr_set, struct list_head *list_node);
  56
  57 /*
  58  * Abbreviations:
  59  * dbs: used as a shortform for demand based switching It helps to keep variable
  60  *      names smaller, simpler
  61  * cdbs: common dbs
  62  * od_*: On-demand governor
  63  * cs_*: Conservative governor
  64  */
  65
  66 /* Governor demand based switching data (per-policy or global). */
  67 struct dbs_data {
  68         struct gov_attr_set attr_set;
  69         void *tuners;
  70         unsigned int min_sampling_rate;
  71         unsigned int ignore_nice_load;
  72         unsigned int sampling_rate;
  73         unsigned int sampling_down_factor;
  74         unsigned int up_threshold;
  75         unsigned int io_is_busy;
  76 };
  77
  78 static inline struct dbs_data *to_dbs_data(struct gov_attr_set *attr_set)
  79 {
  80         return container_of(attr_set, struct dbs_data, attr_set);
  81 }
  82
  83 /* Governor's specific attributes */
  84 struct governor_attr {
  85         struct attribute attr;
  86         ssize_t (*show)(struct gov_attr_set *attr_set, char *buf);
  87         ssize_t (*store)(struct gov_attr_set *attr_set, const char *buf,
  88                          size_t count);
  89 };
  90
  91 #define gov_show_one(_gov, file_name)                                   \
  92 static ssize_t show_##file_name                                         \
  93 (struct gov_attr_set *attr_set, char *buf)                              \
  94 {                                                                       \
  95         struct dbs_data *dbs_data = to_dbs_data(attr_set);              \
  96         struct _gov##_dbs_tuners *tuners = dbs_data->tuners;            \
  97         return sprintf(buf, "%u\n", tuners->file_name);                 \
  98 }
  99
 100 #define gov_show_one_common(file_name)                                  \
 101 static ssize_t show_##file_name                                         \
 102 (struct gov_attr_set *attr_set, char *buf)                              \
 103 {                                                                       \
 104         struct dbs_data *dbs_data = to_dbs_data(attr_set);              \
 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         /* Multiplier for increasing sample delay temporarily. */
 134         unsigned int rate_mult;
 135         /* Status indicators */
 136         bool is_shared;         /* This object is used by multiple CPUs */
 137         bool work_in_progress;  /* Work is being queued up or in progress */
 138 };
 139
 140 static inline void gov_update_sample_delay(struct policy_dbs_info *policy_dbs,
 141                                            unsigned int delay_us)
 142 {
 143         policy_dbs->sample_delay_ns = delay_us * NSEC_PER_USEC;
 144 }
 145
 146 /* Per cpu structures */
 147 struct cpu_dbs_info {
 148         u64 prev_cpu_idle;
 149         u64 prev_cpu_wall;
 150         u64 prev_cpu_nice;
 151         /*
 152          * Used to keep track of load in the previous interval. However, when
 153          * explicitly set to zero, it is used as a flag to ensure that we copy
 154          * the previous load to the current interval only once, upon the first
 155          * wake-up from idle.
 156          */
 157         unsigned int prev_load;
 158         struct update_util_data update_util;
 159         struct policy_dbs_info *policy_dbs;
 160 };
 161
 162 /* Common Governor data across policies */
 163 struct dbs_governor {
 164         struct cpufreq_governor gov;
 165         struct kobj_type kobj_type;
 166
 167         /*
 168          * Common data for platforms that don't set
 169          * CPUFREQ_HAVE_GOVERNOR_PER_POLICY
 170          */
 171         struct dbs_data *gdbs_data;
 172
 173         unsigned int (*gov_dbs_timer)(struct cpufreq_policy *policy);
 174         struct policy_dbs_info *(*alloc)(void);
 175         void (*free)(struct policy_dbs_info *policy_dbs);
 176         int (*init)(struct dbs_data *dbs_data, bool notify);
 177         void (*exit)(struct dbs_data *dbs_data, bool notify);
 178         void (*start)(struct cpufreq_policy *policy);
 179 };
 180
 181 static inline struct dbs_governor *dbs_governor_of(struct cpufreq_policy *policy)
 182 {
 183         return container_of(policy->governor, struct dbs_governor, gov);
 184 }
 185
 186 /* Governor specific operations */
 187 struct od_ops {
 188         unsigned int (*powersave_bias_target)(struct cpufreq_policy *policy,
 189                         unsigned int freq_next, unsigned int relation);
 190 };
 191
 192 unsigned int dbs_update(struct cpufreq_policy *policy);
 193 int cpufreq_governor_dbs(struct cpufreq_policy *policy, unsigned int event);
 194 void od_register_powersave_bias_handler(unsigned int (*f)
 195                 (struct cpufreq_policy *, unsigned int, unsigned int),
 196                 unsigned int powersave_bias);
 197 void od_unregister_powersave_bias_handler(void);
 198 ssize_t store_sampling_rate(struct gov_attr_set *attr_set, const char *buf,
 199                             size_t count);
 200 void gov_update_cpu_data(struct dbs_data *dbs_data);
 201 #endif /* _CPUFREQ_GOVERNOR_H */