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_GOVERNER_H
  18 #define _CPUFREQ_GOVERNER_H
  19
  20 #include <linux/cpufreq.h>
  21 #include <linux/kobject.h>
  22 #include <linux/mutex.h>
  23 #include <linux/workqueue.h>
  24 #include <linux/sysfs.h>
  25
  26 /*
  27  * The polling frequency depends on the capability of the processor. Default
  28  * polling frequency is 1000 times the transition latency of the processor. The
  29  * governor will work on any processor with transition latency <= 10mS, using
  30  * appropriate sampling rate.
  31  *
  32  * For CPUs with transition latency > 10mS (mostly drivers with CPUFREQ_ETERNAL)
  33  * this governor will not work. All times here are in uS.
  34  */
  35 #define MIN_SAMPLING_RATE_RATIO                 (2)
  36 #define LATENCY_MULTIPLIER                      (1000)
  37 #define MIN_LATENCY_MULTIPLIER                  (100)
  38 #define TRANSITION_LATENCY_LIMIT                (10 * 1000 * 1000)
  39
  40 /* Ondemand Sampling types */
  41 enum {OD_NORMAL_SAMPLE, OD_SUB_SAMPLE};
  42
  43 /* Macro creating sysfs show routines */
  44 #define show_one(_gov, file_name, object)                               \
  45 static ssize_t show_##file_name                                         \
  46 (struct kobject *kobj, struct attribute *attr, char *buf)               \
  47 {                                                                       \
  48         return sprintf(buf, "%u\n", _gov##_tuners.object);              \
  49 }
  50
  51 #define define_get_cpu_dbs_routines(_dbs_info)                          \
  52 static struct cpu_dbs_common_info *get_cpu_cdbs(int cpu)                \
  53 {                                                                       \
  54         return &per_cpu(_dbs_info, cpu).cdbs;                           \
  55 }                                                                       \
  56                                                                         \
  57 static void *get_cpu_dbs_info_s(int cpu)                                \
  58 {                                                                       \
  59         return &per_cpu(_dbs_info, cpu);                                \
  60 }
  61
  62 /*
  63  * Abbreviations:
  64  * dbs: used as a shortform for demand based switching It helps to keep variable
  65  *      names smaller, simpler
  66  * cdbs: common dbs
  67  * on_*: On-demand governor
  68  * cs_*: Conservative governor
  69  */
  70
  71 /* Per cpu structures */
  72 struct cpu_dbs_common_info {
  73         int cpu;
  74         u64 prev_cpu_idle;
  75         u64 prev_cpu_wall;
  76         u64 prev_cpu_nice;
  77         struct cpufreq_policy *cur_policy;
  78         struct delayed_work work;
  79         /*
  80          * percpu mutex that serializes governor limit change with gov_dbs_timer
  81          * invocation. We do not want gov_dbs_timer to run when user is changing
  82          * the governor or limits.
  83          */
  84         struct mutex timer_mutex;
  85         ktime_t time_stamp;
  86 };
  87
  88 struct od_cpu_dbs_info_s {
  89         struct cpu_dbs_common_info cdbs;
  90         u64 prev_cpu_iowait;
  91         struct cpufreq_frequency_table *freq_table;
  92         unsigned int freq_lo;
  93         unsigned int freq_lo_jiffies;
  94         unsigned int freq_hi_jiffies;
  95         unsigned int rate_mult;
  96         unsigned int sample_type:1;
  97 };
  98
  99 struct cs_cpu_dbs_info_s {
 100         struct cpu_dbs_common_info cdbs;
 101         unsigned int down_skip;
 102         unsigned int requested_freq;
 103         unsigned int enable:1;
 104 };
 105
 106 /* Governers sysfs tunables */
 107 struct od_dbs_tuners {
 108         unsigned int ignore_nice;
 109         unsigned int sampling_rate;
 110         unsigned int sampling_down_factor;
 111         unsigned int up_threshold;
 112         unsigned int down_differential;
 113         unsigned int powersave_bias;
 114         unsigned int io_is_busy;
 115 };
 116
 117 struct cs_dbs_tuners {
 118         unsigned int ignore_nice;
 119         unsigned int sampling_rate;
 120         unsigned int sampling_down_factor;
 121         unsigned int up_threshold;
 122         unsigned int down_threshold;
 123         unsigned int freq_step;
 124 };
 125
 126 /* Per Governer data */
 127 struct dbs_data {
 128         /* Common across governors */
 129         #define GOV_ONDEMAND            0
 130         #define GOV_CONSERVATIVE        1
 131         int governor;
 132         unsigned int min_sampling_rate;
 133         unsigned int enable; /* number of CPUs using this policy */
 134         struct attribute_group *attr_group;
 135         void *tuners;
 136
 137         /* dbs_mutex protects dbs_enable in governor start/stop */
 138         struct mutex mutex;
 139
 140         struct cpu_dbs_common_info *(*get_cpu_cdbs)(int cpu);
 141         void *(*get_cpu_dbs_info_s)(int cpu);
 142         void (*gov_dbs_timer)(struct work_struct *work);
 143         void (*gov_check_cpu)(int cpu, unsigned int load);
 144
 145         /* Governor specific ops, see below */
 146         void *gov_ops;
 147 };
 148
 149 /* Governor specific ops, will be passed to dbs_data->gov_ops */
 150 struct od_ops {
 151         int (*io_busy)(void);
 152         void (*powersave_bias_init_cpu)(int cpu);
 153         unsigned int (*powersave_bias_target)(struct cpufreq_policy *policy,
 154                         unsigned int freq_next, unsigned int relation);
 155         void (*freq_increase)(struct cpufreq_policy *p, unsigned int freq);
 156 };
 157
 158 struct cs_ops {
 159         struct notifier_block *notifier_block;
 160 };
 161
 162 static inline int delay_for_sampling_rate(unsigned int sampling_rate)
 163 {
 164         int delay = usecs_to_jiffies(sampling_rate);
 165
 166         /* We want all CPUs to do sampling nearly on same jiffy */
 167         if (num_online_cpus() > 1)
 168                 delay -= jiffies % delay;
 169
 170         return delay;
 171 }
 172
 173 u64 get_cpu_idle_time(unsigned int cpu, u64 *wall);
 174 void dbs_check_cpu(struct dbs_data *dbs_data, int cpu);
 175 int cpufreq_governor_dbs(struct dbs_data *dbs_data,
 176                 struct cpufreq_policy *policy, unsigned int event);
 177 #endif /* _CPUFREQ_GOVERNER_H */