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/sched/cpufreq.h>
24 #include <linux/kernel_stat.h>
25 #include <linux/module.h>
26 #include <linux/mutex.h>
27 
28 /* Ondemand Sampling types */
29 enum {OD_NORMAL_SAMPLE, OD_SUB_SAMPLE};
30 
31 /*
32  * Abbreviations:
33  * dbs: used as a shortform for demand based switching It helps to keep variable
34  *	names smaller, simpler
35  * cdbs: common dbs
36  * od_*: On-demand governor
37  * cs_*: Conservative governor
38  */
39 
40 /* Governor demand based switching data (per-policy or global). */
41 struct dbs_data {
42 	struct gov_attr_set attr_set;
43 	void *tuners;
44 	unsigned int ignore_nice_load;
45 	unsigned int sampling_rate;
46 	unsigned int sampling_down_factor;
47 	unsigned int up_threshold;
48 	unsigned int io_is_busy;
49 };
50 
to_dbs_data(struct gov_attr_set * attr_set)51 static inline struct dbs_data *to_dbs_data(struct gov_attr_set *attr_set)
52 {
53 	return container_of(attr_set, struct dbs_data, attr_set);
54 }
55 
56 #define gov_show_one(_gov, file_name)					\
57 static ssize_t show_##file_name						\
58 (struct gov_attr_set *attr_set, char *buf)				\
59 {									\
60 	struct dbs_data *dbs_data = to_dbs_data(attr_set);		\
61 	struct _gov##_dbs_tuners *tuners = dbs_data->tuners;		\
62 	return sprintf(buf, "%u\n", tuners->file_name);			\
63 }
64 
65 #define gov_show_one_common(file_name)					\
66 static ssize_t show_##file_name						\
67 (struct gov_attr_set *attr_set, char *buf)				\
68 {									\
69 	struct dbs_data *dbs_data = to_dbs_data(attr_set);		\
70 	return sprintf(buf, "%u\n", dbs_data->file_name);		\
71 }
72 
73 #define gov_attr_ro(_name)						\
74 static struct governor_attr _name =					\
75 __ATTR(_name, 0444, show_##_name, NULL)
76 
77 #define gov_attr_rw(_name)						\
78 static struct governor_attr _name =					\
79 __ATTR(_name, 0644, show_##_name, store_##_name)
80 
81 /* Common to all CPUs of a policy */
82 struct policy_dbs_info {
83 	struct cpufreq_policy *policy;
84 	/*
85 	 * Per policy mutex that serializes load evaluation from limit-change
86 	 * and work-handler.
87 	 */
88 	struct mutex update_mutex;
89 
90 	u64 last_sample_time;
91 	s64 sample_delay_ns;
92 	atomic_t work_count;
93 	struct irq_work irq_work;
94 	struct work_struct work;
95 	/* dbs_data may be shared between multiple policy objects */
96 	struct dbs_data *dbs_data;
97 	struct list_head list;
98 	/* Multiplier for increasing sample delay temporarily. */
99 	unsigned int rate_mult;
100 	unsigned int idle_periods;	/* For conservative */
101 	/* Status indicators */
102 	bool is_shared;		/* This object is used by multiple CPUs */
103 	bool work_in_progress;	/* Work is being queued up or in progress */
104 };
105 
gov_update_sample_delay(struct policy_dbs_info * policy_dbs,unsigned int delay_us)106 static inline void gov_update_sample_delay(struct policy_dbs_info *policy_dbs,
107 					   unsigned int delay_us)
108 {
109 	policy_dbs->sample_delay_ns = delay_us * NSEC_PER_USEC;
110 }
111 
112 /* Per cpu structures */
113 struct cpu_dbs_info {
114 	u64 prev_cpu_idle;
115 	u64 prev_update_time;
116 	u64 prev_cpu_nice;
117 	/*
118 	 * Used to keep track of load in the previous interval. However, when
119 	 * explicitly set to zero, it is used as a flag to ensure that we copy
120 	 * the previous load to the current interval only once, upon the first
121 	 * wake-up from idle.
122 	 */
123 	unsigned int prev_load;
124 	struct update_util_data update_util;
125 	struct policy_dbs_info *policy_dbs;
126 };
127 
128 /* Common Governor data across policies */
129 struct dbs_governor {
130 	struct cpufreq_governor gov;
131 	struct kobj_type kobj_type;
132 
133 	/*
134 	 * Common data for platforms that don't set
135 	 * CPUFREQ_HAVE_GOVERNOR_PER_POLICY
136 	 */
137 	struct dbs_data *gdbs_data;
138 
139 	unsigned int (*gov_dbs_update)(struct cpufreq_policy *policy);
140 	struct policy_dbs_info *(*alloc)(void);
141 	void (*free)(struct policy_dbs_info *policy_dbs);
142 	int (*init)(struct dbs_data *dbs_data);
143 	void (*exit)(struct dbs_data *dbs_data);
144 	void (*start)(struct cpufreq_policy *policy);
145 };
146 
dbs_governor_of(struct cpufreq_policy * policy)147 static inline struct dbs_governor *dbs_governor_of(struct cpufreq_policy *policy)
148 {
149 	return container_of(policy->governor, struct dbs_governor, gov);
150 }
151 
152 /* Governor callback routines */
153 int cpufreq_dbs_governor_init(struct cpufreq_policy *policy);
154 void cpufreq_dbs_governor_exit(struct cpufreq_policy *policy);
155 int cpufreq_dbs_governor_start(struct cpufreq_policy *policy);
156 void cpufreq_dbs_governor_stop(struct cpufreq_policy *policy);
157 void cpufreq_dbs_governor_limits(struct cpufreq_policy *policy);
158 
159 #define CPUFREQ_DBS_GOVERNOR_INITIALIZER(_name_)			\
160 	{								\
161 		.name = _name_,						\
162 		.dynamic_switching = true,				\
163 		.owner = THIS_MODULE,					\
164 		.init = cpufreq_dbs_governor_init,			\
165 		.exit = cpufreq_dbs_governor_exit,			\
166 		.start = cpufreq_dbs_governor_start,			\
167 		.stop = cpufreq_dbs_governor_stop,			\
168 		.limits = cpufreq_dbs_governor_limits,			\
169 	}
170 
171 /* Governor specific operations */
172 struct od_ops {
173 	unsigned int (*powersave_bias_target)(struct cpufreq_policy *policy,
174 			unsigned int freq_next, unsigned int relation);
175 };
176 
177 unsigned int dbs_update(struct cpufreq_policy *policy);
178 void od_register_powersave_bias_handler(unsigned int (*f)
179 		(struct cpufreq_policy *, unsigned int, unsigned int),
180 		unsigned int powersave_bias);
181 void od_unregister_powersave_bias_handler(void);
182 ssize_t store_sampling_rate(struct gov_attr_set *attr_set, const char *buf,
183 			    size_t count);
184 void gov_update_cpu_data(struct dbs_data *dbs_data);
185 #endif /* _CPUFREQ_GOVERNOR_H */
186