cpufreq_governor.h revision beb0ff390e208e71668a1389e3db02631a88cff5 
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/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 */
41enum {OD_NORMAL_SAMPLE, OD_SUB_SAMPLE};
42
43/* Macro creating sysfs show routines */
44#define show_one(_gov, file_name, object)				\
45static 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)				\
52static struct cpu_dbs_common_info *get_cpu_cdbs(int cpu)		\
53{									\
54	return &per_cpu(_dbs_info, cpu).cdbs;				\
55}									\
56									\
57static 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 * od_*: On-demand governor
68 * cs_*: Conservative governor
69 */
70
71/* Per cpu structures */
72struct 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
88struct 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
99struct 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 */
107struct 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 adj_up_threshold;
113	unsigned int powersave_bias;
114	unsigned int io_is_busy;
115};
116
117struct 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 */
127struct 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	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 */
149struct 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
157struct cs_ops {
158	struct notifier_block *notifier_block;
159};
160
161static 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
172u64 get_cpu_idle_time(unsigned int cpu, u64 *wall);
173void dbs_check_cpu(struct dbs_data *dbs_data, int cpu);
174bool need_load_eval(struct cpu_dbs_common_info *cdbs,
175		unsigned int sampling_rate);
176int cpufreq_governor_dbs(struct dbs_data *dbs_data,
177		struct cpufreq_policy *policy, unsigned int event);
178#endif /* _CPUFREQ_GOVERNOR_H */
179