summaryrefslogtreecommitdiffstats
path: root/include/linux/devfreq.h
blob: f1863dcd83eaf4070cc83762ce9864b9826e1c0e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
/*
 * devfreq: Generic Dynamic Voltage and Frequency Scaling (DVFS) Framework
 *	    for Non-CPU Devices.
 *
 * Copyright (C) 2011 Samsung Electronics
 *	MyungJoo Ham <myungjoo.ham@samsung.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#ifndef __LINUX_DEVFREQ_H__
#define __LINUX_DEVFREQ_H__

#include <linux/device.h>
#include <linux/notifier.h>
#include <linux/pm_opp.h>

#define DEVFREQ_NAME_LEN 16

struct devfreq;

/**
 * struct devfreq_dev_status - Data given from devfreq user device to
 *			     governors. Represents the performance
 *			     statistics.
 * @total_time:		The total time represented by this instance of
 *			devfreq_dev_status
 * @busy_time:		The time that the device was working among the
 *			total_time.
 * @current_frequency:	The operating frequency.
 * @private_data:	An entry not specified by the devfreq framework.
 *			A device and a specific governor may have their
 *			own protocol with private_data. However, because
 *			this is governor-specific, a governor using this
 *			will be only compatible with devices aware of it.
 */
struct devfreq_dev_status {
	/* both since the last measure */
	unsigned long total_time;
	unsigned long busy_time;
	unsigned long current_frequency;
	void *private_data;
};

/*
 * The resulting frequency should be at most this. (this bound is the
 * least upper bound; thus, the resulting freq should be lower or same)
 * If the flag is not set, the resulting frequency should be at most the
 * bound (greatest lower bound)
 */
#define DEVFREQ_FLAG_LEAST_UPPER_BOUND		0x1

/**
 * struct devfreq_dev_profile - Devfreq's user device profile
 * @initial_freq:	The operating frequency when devfreq_add_device() is
 *			called.
 * @polling_ms:		The polling interval in ms. 0 disables polling.
 * @target:		The device should set its operating frequency at
 *			freq or lowest-upper-than-freq value. If freq is
 *			higher than any operable frequency, set maximum.
 *			Before returning, target function should set
 *			freq at the current frequency.
 *			The "flags" parameter's possible values are
 *			explained above with "DEVFREQ_FLAG_*" macros.
 * @get_dev_status:	The device should provide the current performance
 *			status to devfreq, which is used by governors.
 * @get_cur_freq:	The device should provide the current frequency
 *			at which it is operating.
 * @exit:		An optional callback that is called when devfreq
 *			is removing the devfreq object due to error or
 *			from devfreq_remove_device() call. If the user
 *			has registered devfreq->nb at a notifier-head,
 *			this is the time to unregister it.
 * @freq_table:	Optional list of frequencies to support statistics.
 * @max_state:	The size of freq_table.
 */
struct devfreq_dev_profile {
	unsigned long initial_freq;
	unsigned int polling_ms;

	int (*target)(struct device *dev, unsigned long *freq, u32 flags);
	int (*get_dev_status)(struct device *dev,
			      struct devfreq_dev_status *stat);
	int (*get_cur_freq)(struct device *dev, unsigned long *freq);
	void (*exit)(struct device *dev);

	unsigned int *freq_table;
	unsigned int max_state;
};

/**
 * struct devfreq_governor - Devfreq policy governor
 * @node:		list node - contains registered devfreq governors
 * @name:		Governor's name
 * @get_target_freq:	Returns desired operating frequency for the device.
 *			Basically, get_target_freq will run
 *			devfreq_dev_profile.get_dev_status() to get the
 *			status of the device (load = busy_time / total_time).
 *			If no_central_polling is set, this callback is called
 *			only with update_devfreq() notified by OPP.
 * @event_handler:      Callback for devfreq core framework to notify events
 *                      to governors. Events include per device governor
 *                      init and exit, opp changes out of devfreq, suspend
 *                      and resume of per device devfreq during device idle.
 *
 * Note that the callbacks are called with devfreq->lock locked by devfreq.
 */
struct devfreq_governor {
	struct list_head node;

	const char name[DEVFREQ_NAME_LEN];
	int (*get_target_freq)(struct devfreq *this, unsigned long *freq);
	int (*event_handler)(struct devfreq *devfreq,
				unsigned int event, void *data);
};

/**
 * struct devfreq - Device devfreq structure
 * @node:	list node - contains the devices with devfreq that have been
 *		registered.
 * @lock:	a mutex to protect accessing devfreq.
 * @dev:	device registered by devfreq class. dev.parent is the device
 *		using devfreq.
 * @profile:	device-specific devfreq profile
 * @governor:	method how to choose frequency based on the usage.
 * @governor_name:	devfreq governor name for use with this devfreq
 * @nb:		notifier block used to notify devfreq object that it should
 *		reevaluate operable frequencies. Devfreq users may use
 *		devfreq.nb to the corresponding register notifier call chain.
 * @work:	delayed work for load monitoring.
 * @previous_freq:	previously configured frequency value.
 * @data:	Private data of the governor. The devfreq framework does not
 *		touch this.
 * @min_freq:	Limit minimum frequency requested by user (0: none)
 * @max_freq:	Limit maximum frequency requested by user (0: none)
 * @stop_polling:	 devfreq polling status of a device.
 * @total_trans:	Number of devfreq transitions
 * @trans_table:	Statistics of devfreq transitions
 * @time_in_state:	Statistics of devfreq states
 * @last_stat_updated:	The last time stat updated
 *
 * This structure stores the devfreq information for a give device.
 *
 * Note that when a governor accesses entries in struct devfreq in its
 * functions except for the context of callbacks defined in struct
 * devfreq_governor, the governor should protect its access with the
 * struct mutex lock in struct devfreq. A governor may use this mutex
 * to protect its own private data in void *data as well.
 */
struct devfreq {
	struct list_head node;

	struct mutex lock;
	struct device dev;
	struct devfreq_dev_profile *profile;
	const struct devfreq_governor *governor;
	char governor_name[DEVFREQ_NAME_LEN];
	struct notifier_block nb;
	struct delayed_work work;

	unsigned long previous_freq;

	void *data; /* private data for governors */

	unsigned long min_freq;
	unsigned long max_freq;
	bool stop_polling;

	/* information for device frequency transition */
	unsigned int total_trans;
	unsigned int *trans_table;
	unsigned long *time_in_state;
	unsigned long last_stat_updated;
};

#if defined(CONFIG_PM_DEVFREQ)
extern struct devfreq *devfreq_add_device(struct device *dev,
				  struct devfreq_dev_profile *profile,
				  const char *governor_name,
				  void *data);
extern int devfreq_remove_device(struct devfreq *devfreq);
extern struct devfreq *devm_devfreq_add_device(struct device *dev,
				  struct devfreq_dev_profile *profile,
				  const char *governor_name,
				  void *data);
extern void devm_devfreq_remove_device(struct device *dev,
				  struct devfreq *devfreq);

/* Supposed to be called by PM_SLEEP/PM_RUNTIME callbacks */
extern int devfreq_suspend_device(struct devfreq *devfreq);
extern int devfreq_resume_device(struct devfreq *devfreq);

/* Helper functions for devfreq user device driver with OPP. */
extern struct dev_pm_opp *devfreq_recommended_opp(struct device *dev,
					   unsigned long *freq, u32 flags);
extern int devfreq_register_opp_notifier(struct device *dev,
					 struct devfreq *devfreq);
extern int devfreq_unregister_opp_notifier(struct device *dev,
					   struct devfreq *devfreq);
extern int devm_devfreq_register_opp_notifier(struct device *dev,
					      struct devfreq *devfreq);
extern void devm_devfreq_unregister_opp_notifier(struct device *dev,
						struct devfreq *devfreq);

#if IS_ENABLED(CONFIG_DEVFREQ_GOV_SIMPLE_ONDEMAND)
/**
 * struct devfreq_simple_ondemand_data - void *data fed to struct devfreq
 *	and devfreq_add_device
 * @upthreshold:	If the load is over this value, the frequency jumps.
 *			Specify 0 to use the default. Valid value = 0 to 100.
 * @downdifferential:	If the load is under upthreshold - downdifferential,
 *			the governor may consider slowing the frequency down.
 *			Specify 0 to use the default. Valid value = 0 to 100.
 *			downdifferential < upthreshold must hold.
 *
 * If the fed devfreq_simple_ondemand_data pointer is NULL to the governor,
 * the governor uses the default values.
 */
struct devfreq_simple_ondemand_data {
	unsigned int upthreshold;
	unsigned int downdifferential;
};
#endif

#else /* !CONFIG_PM_DEVFREQ */
static inline struct devfreq *devfreq_add_device(struct device *dev,
					  struct devfreq_dev_profile *profile,
					  const char *governor_name,
					  void *data)
{
	return ERR_PTR(-ENOSYS);
}

static inline int devfreq_remove_device(struct devfreq *devfreq)
{
	return 0;
}

static inline struct devfreq *devm_devfreq_add_device(struct device *dev,
					struct devfreq_dev_profile *profile,
					const char *governor_name,
					void *data)
{
	return ERR_PTR(-ENOSYS);
}

static inline void devm_devfreq_remove_device(struct device *dev,
					struct devfreq *devfreq)
{
}

static inline int devfreq_suspend_device(struct devfreq *devfreq)
{
	return 0;
}

static inline int devfreq_resume_device(struct devfreq *devfreq)
{
	return 0;
}

static inline struct dev_pm_opp *devfreq_recommended_opp(struct device *dev,
					   unsigned long *freq, u32 flags)
{
	return ERR_PTR(-EINVAL);
}

static inline int devfreq_register_opp_notifier(struct device *dev,
					 struct devfreq *devfreq)
{
	return -EINVAL;
}

static inline int devfreq_unregister_opp_notifier(struct device *dev,
					   struct devfreq *devfreq)
{
	return -EINVAL;
}

static inline int devm_devfreq_register_opp_notifier(struct device *dev,
						     struct devfreq *devfreq)
{
	return -EINVAL;
}

static inline void devm_devfreq_unregister_opp_notifier(struct device *dev,
							struct devfreq *devfreq)
{
}
#endif /* CONFIG_PM_DEVFREQ */

#endif /* __LINUX_DEVFREQ_H__ */