2 * drivers/cpufreq/cpufreq_governor.h
4 * Header file for CPUFreq governors common code
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>
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.
17 #ifndef _CPUFREQ_GOVERNOR_H
18 #define _CPUFREQ_GOVERNOR_H
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>
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.
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).
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)
41 /* Ondemand Sampling types */
42 enum {OD_NORMAL_SAMPLE, OD_SUB_SAMPLE};
46 * dbs: used as a shortform for demand based switching It helps to keep variable
47 * names smaller, simpler
49 * od_*: On-demand governor
50 * cs_*: Conservative governor
53 /* Governor demand based switching data (per-policy or global). */
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;
65 struct list_head policy_dbs_list;
67 * Protect concurrent updates to governor tunables from sysfs,
68 * policy_dbs_list and usage_count.
73 /* Governor's specific attributes */
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,
82 #define gov_show_one(_gov, file_name) \
83 static ssize_t show_##file_name \
84 (struct dbs_data *dbs_data, char *buf) \
86 struct _gov##_dbs_tuners *tuners = dbs_data->tuners; \
87 return sprintf(buf, "%u\n", tuners->file_name); \
90 #define gov_show_one_common(file_name) \
91 static ssize_t show_##file_name \
92 (struct dbs_data *dbs_data, char *buf) \
94 return sprintf(buf, "%u\n", dbs_data->file_name); \
97 #define gov_attr_ro(_name) \
98 static struct governor_attr _name = \
99 __ATTR(_name, 0444, show_##_name, NULL)
101 #define gov_attr_rw(_name) \
102 static struct governor_attr _name = \
103 __ATTR(_name, 0644, show_##_name, store_##_name)
105 /* Common to all CPUs of a policy */
106 struct policy_dbs_info {
107 struct cpufreq_policy *policy;
109 * Per policy mutex that serializes load evaluation from limit-change
112 struct mutex timer_mutex;
114 u64 last_sample_time;
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 */
129 static inline void gov_update_sample_delay(struct policy_dbs_info *policy_dbs,
130 unsigned int delay_us)
132 policy_dbs->sample_delay_ns = delay_us * NSEC_PER_USEC;
135 /* Per cpu structures */
136 struct cpu_dbs_info {
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
146 unsigned int prev_load;
147 struct update_util_data update_util;
148 struct policy_dbs_info *policy_dbs;
151 /* Per policy Governors sysfs tunables */
152 struct od_dbs_tuners {
153 unsigned int powersave_bias;
156 struct cs_dbs_tuners {
157 unsigned int down_threshold;
158 unsigned int freq_step;
161 /* Common Governor data across policies */
162 struct dbs_governor {
163 struct cpufreq_governor gov;
164 struct kobj_type kobj_type;
167 * Common data for platforms that don't set
168 * CPUFREQ_HAVE_GOVERNOR_PER_POLICY
170 struct dbs_data *gdbs_data;
172 unsigned int (*gov_dbs_timer)(struct cpufreq_policy *policy);
173 struct policy_dbs_info *(*alloc)(void);
174 void (*free)(struct policy_dbs_info *policy_dbs);
175 int (*init)(struct dbs_data *dbs_data, bool notify);
176 void (*exit)(struct dbs_data *dbs_data, bool notify);
177 void (*start)(struct cpufreq_policy *policy);
180 static inline struct dbs_governor *dbs_governor_of(struct cpufreq_policy *policy)
182 return container_of(policy->governor, struct dbs_governor, gov);
185 /* Governor specific operations */
187 unsigned int (*powersave_bias_target)(struct cpufreq_policy *policy,
188 unsigned int freq_next, unsigned int relation);
191 extern struct mutex dbs_data_mutex;
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 dbs_data *dbs_data, const char *buf,
200 void gov_update_cpu_data(struct dbs_data *dbs_data);
201 #endif /* _CPUFREQ_GOVERNOR_H */