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
};
44 /* create helper routines */
45 #define define_get_cpu_dbs_routines(_dbs_info) \
46 static struct cpu_dbs_info *get_cpu_cdbs(int cpu) \
48 return &per_cpu(_dbs_info, cpu).cdbs; \
51 static void *get_cpu_dbs_info_s(int cpu) \
53 return &per_cpu(_dbs_info, cpu); \
58 * dbs: used as a shortform for demand based switching It helps to keep variable
59 * names smaller, simpler
61 * od_*: On-demand governor
62 * cs_*: Conservative governor
65 /* Governor demand based switching data (per-policy or global). */
69 unsigned int min_sampling_rate
;
70 unsigned int ignore_nice_load
;
71 unsigned int sampling_rate
;
72 unsigned int sampling_down_factor
;
73 unsigned int up_threshold
;
76 struct list_head policy_dbs_list
;
78 * Protect concurrent updates to governor tunables from sysfs,
79 * policy_dbs_list and usage_count.
84 /* Governor's specific attributes */
86 struct governor_attr
{
87 struct attribute attr
;
88 ssize_t (*show
)(struct dbs_data
*dbs_data
, char *buf
);
89 ssize_t (*store
)(struct dbs_data
*dbs_data
, const char *buf
,
93 #define gov_show_one(_gov, file_name) \
94 static ssize_t show_##file_name \
95 (struct dbs_data *dbs_data, char *buf) \
97 struct _gov##_dbs_tuners *tuners = dbs_data->tuners; \
98 return sprintf(buf, "%u\n", tuners->file_name); \
101 #define gov_show_one_common(file_name) \
102 static ssize_t show_##file_name \
103 (struct dbs_data *dbs_data, char *buf) \
105 return sprintf(buf, "%u\n", dbs_data->file_name); \
108 #define gov_attr_ro(_name) \
109 static struct governor_attr _name = \
110 __ATTR(_name, 0444, show_##_name, NULL)
112 #define gov_attr_rw(_name) \
113 static struct governor_attr _name = \
114 __ATTR(_name, 0644, show_##_name, store_##_name)
116 /* Common to all CPUs of a policy */
117 struct policy_dbs_info
{
118 struct cpufreq_policy
*policy
;
120 * Per policy mutex that serializes load evaluation from limit-change
123 struct mutex timer_mutex
;
125 u64 last_sample_time
;
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
;
135 static inline void gov_update_sample_delay(struct policy_dbs_info
*policy_dbs
,
136 unsigned int delay_us
)
138 policy_dbs
->sample_delay_ns
= delay_us
* NSEC_PER_USEC
;
141 /* Per cpu structures */
142 struct cpu_dbs_info
{
147 * Used to keep track of load in the previous interval. However, when
148 * explicitly set to zero, it is used as a flag to ensure that we copy
149 * the previous load to the current interval only once, upon the first
152 unsigned int prev_load
;
153 struct update_util_data update_util
;
154 struct policy_dbs_info
*policy_dbs
;
157 struct od_cpu_dbs_info_s
{
158 struct cpu_dbs_info cdbs
;
159 struct cpufreq_frequency_table
*freq_table
;
160 unsigned int freq_lo
;
161 unsigned int freq_lo_jiffies
;
162 unsigned int freq_hi_jiffies
;
163 unsigned int rate_mult
;
164 unsigned int sample_type
:1;
167 struct cs_cpu_dbs_info_s
{
168 struct cpu_dbs_info cdbs
;
169 unsigned int down_skip
;
170 unsigned int requested_freq
;
173 /* Per policy Governors sysfs tunables */
174 struct od_dbs_tuners
{
175 unsigned int powersave_bias
;
176 unsigned int io_is_busy
;
179 struct cs_dbs_tuners
{
180 unsigned int down_threshold
;
181 unsigned int freq_step
;
184 /* Common Governor data across policies */
185 struct dbs_governor
{
186 struct cpufreq_governor gov
;
188 #define GOV_ONDEMAND 0
189 #define GOV_CONSERVATIVE 1
191 struct kobj_type kobj_type
;
194 * Common data for platforms that don't set
195 * CPUFREQ_HAVE_GOVERNOR_PER_POLICY
197 struct dbs_data
*gdbs_data
;
199 struct cpu_dbs_info
*(*get_cpu_cdbs
)(int cpu
);
200 void *(*get_cpu_dbs_info_s
)(int cpu
);
201 unsigned int (*gov_dbs_timer
)(struct cpufreq_policy
*policy
);
202 void (*gov_check_cpu
)(int cpu
, unsigned int load
);
203 int (*init
)(struct dbs_data
*dbs_data
, bool notify
);
204 void (*exit
)(struct dbs_data
*dbs_data
, bool notify
);
206 /* Governor specific ops, see below */
210 static inline struct dbs_governor
*dbs_governor_of(struct cpufreq_policy
*policy
)
212 return container_of(policy
->governor
, struct dbs_governor
, gov
);
215 /* Governor specific ops, will be passed to dbs_data->gov_ops */
217 void (*powersave_bias_init_cpu
)(int cpu
);
218 unsigned int (*powersave_bias_target
)(struct cpufreq_policy
*policy
,
219 unsigned int freq_next
, unsigned int relation
);
220 void (*freq_increase
)(struct cpufreq_policy
*policy
, unsigned int freq
);
223 static inline int delay_for_sampling_rate(unsigned int sampling_rate
)
225 int delay
= usecs_to_jiffies(sampling_rate
);
227 /* We want all CPUs to do sampling nearly on same jiffy */
228 if (num_online_cpus() > 1)
229 delay
-= jiffies
% delay
;
234 extern struct mutex dbs_data_mutex
;
235 void dbs_check_cpu(struct cpufreq_policy
*policy
);
236 int cpufreq_governor_dbs(struct cpufreq_policy
*policy
, unsigned int event
);
237 void od_register_powersave_bias_handler(unsigned int (*f
)
238 (struct cpufreq_policy
*, unsigned int, unsigned int),
239 unsigned int powersave_bias
);
240 void od_unregister_powersave_bias_handler(void);
241 #endif /* _CPUFREQ_GOVERNOR_H */