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 };
  86
  87 struct od_cpu_dbs_info_s {
  88         struct cpu_dbs_common_info cdbs;
  89         u64 prev_cpu_iowait;
  90         struct cpufreq_frequency_table *freq_table;
  91         unsigned int freq_lo;
  92         unsigned int freq_lo_jiffies;
  93         unsigned int freq_hi_jiffies;
  94         unsigned int rate_mult;
  95         unsigned int sample_type:1;
  96 };
  97
  98 struct cs_cpu_dbs_info_s {
  99         struct cpu_dbs_common_info cdbs;
 100         unsigned int down_skip;
 101         unsigned int requested_freq;
 102         unsigned int enable:1;
 103 };
 104
 105 /* Governers sysfs tunables */
 106 struct od_dbs_tuners {
 107         unsigned int ignore_nice;
 108         unsigned int sampling_rate;
 109         unsigned int sampling_down_factor;
 110         unsigned int up_threshold;
 111         unsigned int down_differential;
 112         unsigned int powersave_bias;
 113         unsigned int io_is_busy;
 114 };
 115
 116 struct cs_dbs_tuners {
 117         unsigned int ignore_nice;
 118         unsigned int sampling_rate;
 119         unsigned int sampling_down_factor;
 120         unsigned int up_threshold;
 121         unsigned int down_threshold;
 122         unsigned int freq_step;
 123 };
 124
 125 /* Per Governer data */
 126 struct dbs_data {
 127         /* Common across governors */
 128         #define GOV_ONDEMAND            0
 129         #define GOV_CONSERVATIVE        1
 130         int governor;
 131         unsigned int min_sampling_rate;
 132         unsigned int enable; /* number of CPUs using this policy */
 133         struct attribute_group *attr_group;
 134         void *tuners;
 135
 136         /* dbs_mutex protects dbs_enable in governor start/stop */
 137         struct mutex mutex;
 138
 139         struct cpu_dbs_common_info *(*get_cpu_cdbs)(int cpu);
 140         void *(*get_cpu_dbs_info_s)(int cpu);
 141         void (*gov_dbs_timer)(struct work_struct *work);
 142         void (*gov_check_cpu)(int cpu, unsigned int load);
 143
 144         /* Governor specific ops, see below */
 145         void *gov_ops;
 146 };
 147
 148 /* Governor specific ops, will be passed to dbs_data->gov_ops */
 149 struct od_ops {
 150         int (*io_busy)(void);
 151         void (*powersave_bias_init_cpu)(int cpu);
 152         unsigned int (*powersave_bias_target)(struct cpufreq_policy *policy,
 153                         unsigned int freq_next, unsigned int relation);
 154         void (*freq_increase)(struct cpufreq_policy *p, unsigned int freq);
 155 };
 156
 157 struct cs_ops {
 158         struct notifier_block *notifier_block;
 159 };
 160
 161 static inline int delay_for_sampling_rate(unsigned int sampling_rate)
 162 {
 163         int delay = usecs_to_jiffies(sampling_rate);
 164
 165         /* We want all CPUs to do sampling nearly on same jiffy */
 166         if (num_online_cpus() > 1)
 167                 delay -= jiffies % delay;
 168
 169         return delay;
 170 }
 171
 172 u64 get_cpu_idle_time(unsigned int cpu, u64 *wall);
 173 void dbs_check_cpu(struct dbs_data *dbs_data, int cpu);
 174 int cpufreq_governor_dbs(struct dbs_data *dbs_data,
 175                 struct cpufreq_policy *policy, unsigned int event);
 176 #endif /* _CPUFREQ_GOVERNER_H */