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 /* 45 * Abbreviations: 46 * dbs: used as a shortform for demand based switching It helps to keep variable 47 * names smaller, simpler 48 * cdbs: common dbs 49 * od_*: On-demand governor 50 * cs_*: Conservative governor 51 */ 52 53 /* Governor demand based switching data (per-policy or global). */ 54 struct dbs_data { 55 int usage_count; 56 void *tuners; 57 unsigned int min_sampling_rate; 58 unsigned int ignore_nice_load; 59 unsigned int sampling_rate; 60 unsigned int sampling_down_factor; 61 unsigned int up_threshold; 62 unsigned int io_is_busy; 63 64 struct kobject kobj; 65 struct list_head policy_dbs_list; 66 /* 67 * Protect concurrent updates to governor tunables from sysfs, 68 * policy_dbs_list and usage_count. 69 */ 70 struct mutex mutex; 71 }; 72 73 /* Governor's specific attributes */ 74 struct dbs_data; 75 struct governor_attr { 76 struct attribute attr; 77 ssize_t (*show)(struct dbs_data *dbs_data, char *buf); 78 ssize_t (*store)(struct dbs_data *dbs_data, const char *buf, 79 size_t count); 80 }; 81 82 #define gov_show_one(_gov, file_name) \ 83 static ssize_t show_##file_name \ 84 (struct dbs_data *dbs_data, char *buf) \ 85 { \ 86 struct _gov##_dbs_tuners *tuners = dbs_data->tuners; \ 87 return sprintf(buf, "%u\n", tuners->file_name); \ 88 } 89 90 #define gov_show_one_common(file_name) \ 91 static ssize_t show_##file_name \ 92 (struct dbs_data *dbs_data, char *buf) \ 93 { \ 94 return sprintf(buf, "%u\n", dbs_data->file_name); \ 95 } 96 97 #define gov_attr_ro(_name) \ 98 static struct governor_attr _name = \ 99 __ATTR(_name, 0444, show_##_name, NULL) 100 101 #define gov_attr_rw(_name) \ 102 static struct governor_attr _name = \ 103 __ATTR(_name, 0644, show_##_name, store_##_name) 104 105 /* Common to all CPUs of a policy */ 106 struct policy_dbs_info { 107 struct cpufreq_policy *policy; 108 /* 109 * Per policy mutex that serializes load evaluation from limit-change 110 * and work-handler. 111 */ 112 struct mutex timer_mutex; 113 114 u64 last_sample_time; 115 s64 sample_delay_ns; 116 atomic_t work_count; 117 struct irq_work irq_work; 118 struct work_struct work; 119 /* dbs_data may be shared between multiple policy objects */ 120 struct dbs_data *dbs_data; 121 struct list_head list; 122 /* Multiplier for increasing sample delay temporarily. */ 123 unsigned int rate_mult; 124 /* Status indicators */ 125 bool is_shared; /* This object is used by multiple CPUs */ 126 bool work_in_progress; /* Work is being queued up or in progress */ 127 }; 128 129 static inline void gov_update_sample_delay(struct policy_dbs_info *policy_dbs, 130 unsigned int delay_us) 131 { 132 policy_dbs->sample_delay_ns = delay_us * NSEC_PER_USEC; 133 } 134 135 /* Per cpu structures */ 136 struct cpu_dbs_info { 137 u64 prev_cpu_idle; 138 u64 prev_cpu_wall; 139 u64 prev_cpu_nice; 140 /* 141 * Used to keep track of load in the previous interval. However, when 142 * explicitly set to zero, it is used as a flag to ensure that we copy 143 * the previous load to the current interval only once, upon the first 144 * wake-up from idle. 145 */ 146 unsigned int prev_load; 147 struct update_util_data update_util; 148 struct policy_dbs_info *policy_dbs; 149 }; 150 151 /* Common Governor data across policies */ 152 struct dbs_governor { 153 struct cpufreq_governor gov; 154 struct kobj_type kobj_type; 155 156 /* 157 * Common data for platforms that don't set 158 * CPUFREQ_HAVE_GOVERNOR_PER_POLICY 159 */ 160 struct dbs_data *gdbs_data; 161 162 unsigned int (*gov_dbs_timer)(struct cpufreq_policy *policy); 163 struct policy_dbs_info *(*alloc)(void); 164 void (*free)(struct policy_dbs_info *policy_dbs); 165 int (*init)(struct dbs_data *dbs_data, bool notify); 166 void (*exit)(struct dbs_data *dbs_data, bool notify); 167 void (*start)(struct cpufreq_policy *policy); 168 }; 169 170 static inline struct dbs_governor *dbs_governor_of(struct cpufreq_policy *policy) 171 { 172 return container_of(policy->governor, struct dbs_governor, gov); 173 } 174 175 /* Governor specific operations */ 176 struct od_ops { 177 unsigned int (*powersave_bias_target)(struct cpufreq_policy *policy, 178 unsigned int freq_next, unsigned int relation); 179 }; 180 181 unsigned int dbs_update(struct cpufreq_policy *policy); 182 int cpufreq_governor_dbs(struct cpufreq_policy *policy, unsigned int event); 183 void od_register_powersave_bias_handler(unsigned int (*f) 184 (struct cpufreq_policy *, unsigned int, unsigned int), 185 unsigned int powersave_bias); 186 void od_unregister_powersave_bias_handler(void); 187 ssize_t store_sampling_rate(struct dbs_data *dbs_data, const char *buf, 188 size_t count); 189 void gov_update_cpu_data(struct dbs_data *dbs_data); 190 #endif /* _CPUFREQ_GOVERNOR_H */ 191