1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3  * drivers/cpufreq/cpufreq_governor.h
4  *
5  * Header file for CPUFreq governors common code
6  *
7  * Copyright	(C) 2001 Russell King
8  *		(C) 2003 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>.
9  *		(C) 2003 Jun Nakajima <jun.nakajima@intel.com>
10  *		(C) 2009 Alexander Clouter <alex@digriz.org.uk>
11  *		(c) 2012 Viresh Kumar <viresh.kumar@linaro.org>
12  */
13 
14 #ifndef _CPUFREQ_GOVERNOR_H
15 #define _CPUFREQ_GOVERNOR_H
16 
17 #include <linux/atomic.h>
18 #include <linux/irq_work.h>
19 #include <linux/cpufreq.h>
20 #include <linux/sched/cpufreq.h>
21 #include <linux/kernel_stat.h>
22 #include <linux/module.h>
23 #include <linux/mutex.h>
24 
25 /* Ondemand Sampling types */
26 enum {OD_NORMAL_SAMPLE, OD_SUB_SAMPLE};
27 
28 /*
29  * Abbreviations:
30  * dbs: used as a shortform for demand based switching It helps to keep variable
31  *	names smaller, simpler
32  * cdbs: common dbs
33  * od_*: On-demand governor
34  * cs_*: Conservative governor
35  */
36 
37 /* Governor demand based switching data (per-policy or global). */
38 struct dbs_data {
39 	struct gov_attr_set attr_set;
40 	struct dbs_governor *gov;
41 	void *tuners;
42 	unsigned int ignore_nice_load;
43 	unsigned int sampling_rate;
44 	unsigned int sampling_down_factor;
45 	unsigned int up_threshold;
46 	unsigned int io_is_busy;
47 };
48 
49 static inline struct dbs_data *to_dbs_data(struct gov_attr_set *attr_set)
50 {
51 	return container_of(attr_set, struct dbs_data, attr_set);
52 }
53 
54 #define gov_show_one(_gov, file_name)					\
55 static ssize_t file_name##_show						\
56 (struct gov_attr_set *attr_set, char *buf)				\
57 {									\
58 	struct dbs_data *dbs_data = to_dbs_data(attr_set);		\
59 	struct _gov##_dbs_tuners *tuners = dbs_data->tuners;		\
60 	return sprintf(buf, "%u\n", tuners->file_name);			\
61 }
62 
63 #define gov_show_one_common(file_name)					\
64 static ssize_t file_name##_show						\
65 (struct gov_attr_set *attr_set, char *buf)				\
66 {									\
67 	struct dbs_data *dbs_data = to_dbs_data(attr_set);		\
68 	return sprintf(buf, "%u\n", dbs_data->file_name);		\
69 }
70 
71 #define gov_attr_ro(_name)						\
72 static struct governor_attr _name = __ATTR_RO(_name)
73 
74 #define gov_attr_rw(_name)						\
75 static struct governor_attr _name = __ATTR_RW(_name)
76 
77 /* Common to all CPUs of a policy */
78 struct policy_dbs_info {
79 	struct cpufreq_policy *policy;
80 	/*
81 	 * Per policy mutex that serializes load evaluation from limit-change
82 	 * and work-handler.
83 	 */
84 	struct mutex update_mutex;
85 
86 	u64 last_sample_time;
87 	s64 sample_delay_ns;
88 	atomic_t work_count;
89 	struct irq_work irq_work;
90 	struct work_struct work;
91 	/* dbs_data may be shared between multiple policy objects */
92 	struct dbs_data *dbs_data;
93 	struct list_head list;
94 	/* Multiplier for increasing sample delay temporarily. */
95 	unsigned int rate_mult;
96 	unsigned int idle_periods;	/* For conservative */
97 	/* Status indicators */
98 	bool is_shared;		/* This object is used by multiple CPUs */
99 	bool work_in_progress;	/* Work is being queued up or in progress */
100 };
101 
102 static inline void gov_update_sample_delay(struct policy_dbs_info *policy_dbs,
103 					   unsigned int delay_us)
104 {
105 	policy_dbs->sample_delay_ns = delay_us * NSEC_PER_USEC;
106 }
107 
108 /* Per cpu structures */
109 struct cpu_dbs_info {
110 	u64 prev_cpu_idle;
111 	u64 prev_update_time;
112 	u64 prev_cpu_nice;
113 	/*
114 	 * Used to keep track of load in the previous interval. However, when
115 	 * explicitly set to zero, it is used as a flag to ensure that we copy
116 	 * the previous load to the current interval only once, upon the first
117 	 * wake-up from idle.
118 	 */
119 	unsigned int prev_load;
120 	struct update_util_data update_util;
121 	struct policy_dbs_info *policy_dbs;
122 };
123 
124 /* Common Governor data across policies */
125 struct dbs_governor {
126 	struct cpufreq_governor gov;
127 	struct kobj_type kobj_type;
128 
129 	/*
130 	 * Common data for platforms that don't set
131 	 * CPUFREQ_HAVE_GOVERNOR_PER_POLICY
132 	 */
133 	struct dbs_data *gdbs_data;
134 
135 	unsigned int (*gov_dbs_update)(struct cpufreq_policy *policy);
136 	struct policy_dbs_info *(*alloc)(void);
137 	void (*free)(struct policy_dbs_info *policy_dbs);
138 	int (*init)(struct dbs_data *dbs_data);
139 	void (*exit)(struct dbs_data *dbs_data);
140 	void (*start)(struct cpufreq_policy *policy);
141 };
142 
143 static inline struct dbs_governor *dbs_governor_of(struct cpufreq_policy *policy)
144 {
145 	return container_of(policy->governor, struct dbs_governor, gov);
146 }
147 
148 /* Governor callback routines */
149 int cpufreq_dbs_governor_init(struct cpufreq_policy *policy);
150 void cpufreq_dbs_governor_exit(struct cpufreq_policy *policy);
151 int cpufreq_dbs_governor_start(struct cpufreq_policy *policy);
152 void cpufreq_dbs_governor_stop(struct cpufreq_policy *policy);
153 void cpufreq_dbs_governor_limits(struct cpufreq_policy *policy);
154 
155 #define CPUFREQ_DBS_GOVERNOR_INITIALIZER(_name_)			\
156 	{								\
157 		.name = _name_,						\
158 		.flags = CPUFREQ_GOV_DYNAMIC_SWITCHING,			\
159 		.owner = THIS_MODULE,					\
160 		.init = cpufreq_dbs_governor_init,			\
161 		.exit = cpufreq_dbs_governor_exit,			\
162 		.start = cpufreq_dbs_governor_start,			\
163 		.stop = cpufreq_dbs_governor_stop,			\
164 		.limits = cpufreq_dbs_governor_limits,			\
165 	}
166 
167 /* Governor specific operations */
168 struct od_ops {
169 	unsigned int (*powersave_bias_target)(struct cpufreq_policy *policy,
170 			unsigned int freq_next, unsigned int relation);
171 };
172 
173 unsigned int dbs_update(struct cpufreq_policy *policy);
174 void od_register_powersave_bias_handler(unsigned int (*f)
175 		(struct cpufreq_policy *, unsigned int, unsigned int),
176 		unsigned int powersave_bias);
177 void od_unregister_powersave_bias_handler(void);
178 ssize_t sampling_rate_store(struct gov_attr_set *attr_set, const char *buf,
179 			    size_t count);
180 void gov_update_cpu_data(struct dbs_data *dbs_data);
181 #endif /* _CPUFREQ_GOVERNOR_H */
182