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1/*
2 * devfreq: Generic Dynamic Voltage and Frequency Scaling (DVFS) Framework
3 * for Non-CPU Devices.
4 *
5 * Copyright (C) 2011 Samsung Electronics
6 * MyungJoo Ham <myungjoo.ham@samsung.com>
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2 as
10 * published by the Free Software Foundation.
11 */
12
13#ifndef __LINUX_DEVFREQ_H__
14#define __LINUX_DEVFREQ_H__
15
16#include <linux/device.h>
17#include <linux/notifier.h>
e4db1c74 18#include <linux/pm_opp.h>
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19
20#define DEVFREQ_NAME_LEN 16
21
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22/* DEVFREQ notifier interface */
23#define DEVFREQ_TRANSITION_NOTIFIER (0)
24
25/* Transition notifiers of DEVFREQ_TRANSITION_NOTIFIER */
26#define DEVFREQ_PRECHANGE (0)
27#define DEVFREQ_POSTCHANGE (1)
28
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29struct devfreq;
30
31/**
32 * struct devfreq_dev_status - Data given from devfreq user device to
33 * governors. Represents the performance
34 * statistics.
e09651fc 35 * @total_time: The total time represented by this instance of
a3c98b8b 36 * devfreq_dev_status
e09651fc 37 * @busy_time: The time that the device was working among the
a3c98b8b 38 * total_time.
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39 * @current_frequency: The operating frequency.
40 * @private_data: An entry not specified by the devfreq framework.
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41 * A device and a specific governor may have their
42 * own protocol with private_data. However, because
43 * this is governor-specific, a governor using this
44 * will be only compatible with devices aware of it.
45 */
46struct devfreq_dev_status {
47 /* both since the last measure */
48 unsigned long total_time;
49 unsigned long busy_time;
50 unsigned long current_frequency;
1a51cfdc 51 void *private_data;
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52};
53
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54/*
55 * The resulting frequency should be at most this. (this bound is the
56 * least upper bound; thus, the resulting freq should be lower or same)
57 * If the flag is not set, the resulting frequency should be at most the
58 * bound (greatest lower bound)
59 */
60#define DEVFREQ_FLAG_LEAST_UPPER_BOUND 0x1
61
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62/**
63 * struct devfreq_dev_profile - Devfreq's user device profile
e09651fc 64 * @initial_freq: The operating frequency when devfreq_add_device() is
a3c98b8b 65 * called.
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66 * @polling_ms: The polling interval in ms. 0 disables polling.
67 * @target: The device should set its operating frequency at
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68 * freq or lowest-upper-than-freq value. If freq is
69 * higher than any operable frequency, set maximum.
70 * Before returning, target function should set
71 * freq at the current frequency.
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72 * The "flags" parameter's possible values are
73 * explained above with "DEVFREQ_FLAG_*" macros.
e09651fc 74 * @get_dev_status: The device should provide the current performance
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75 * status to devfreq. Governors are recommended not to
76 * use this directly. Instead, governors are recommended
77 * to use devfreq_update_stats() along with
78 * devfreq.last_status.
e09651fc 79 * @get_cur_freq: The device should provide the current frequency
7f98a905 80 * at which it is operating.
e09651fc 81 * @exit: An optional callback that is called when devfreq
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82 * is removing the devfreq object due to error or
83 * from devfreq_remove_device() call. If the user
84 * has registered devfreq->nb at a notifier-head,
85 * this is the time to unregister it.
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86 * @freq_table: Optional list of frequencies to support statistics.
87 * @max_state: The size of freq_table.
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88 */
89struct devfreq_dev_profile {
90 unsigned long initial_freq;
91 unsigned int polling_ms;
92
ab5f299f 93 int (*target)(struct device *dev, unsigned long *freq, u32 flags);
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94 int (*get_dev_status)(struct device *dev,
95 struct devfreq_dev_status *stat);
7f98a905 96 int (*get_cur_freq)(struct device *dev, unsigned long *freq);
a3c98b8b 97 void (*exit)(struct device *dev);
e552bbaf 98
0ec09ac2 99 unsigned long *freq_table;
e552bbaf 100 unsigned int max_state;
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101};
102
103/**
104 * struct devfreq_governor - Devfreq policy governor
3aa173b8 105 * @node: list node - contains registered devfreq governors
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106 * @name: Governor's name
107 * @get_target_freq: Returns desired operating frequency for the device.
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108 * Basically, get_target_freq will run
109 * devfreq_dev_profile.get_dev_status() to get the
110 * status of the device (load = busy_time / total_time).
111 * If no_central_polling is set, this callback is called
112 * only with update_devfreq() notified by OPP.
e09651fc 113 * @event_handler: Callback for devfreq core framework to notify events
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114 * to governors. Events include per device governor
115 * init and exit, opp changes out of devfreq, suspend
116 * and resume of per device devfreq during device idle.
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117 *
118 * Note that the callbacks are called with devfreq->lock locked by devfreq.
119 */
120struct devfreq_governor {
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121 struct list_head node;
122
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123 const char name[DEVFREQ_NAME_LEN];
124 int (*get_target_freq)(struct devfreq *this, unsigned long *freq);
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125 int (*event_handler)(struct devfreq *devfreq,
126 unsigned int event, void *data);
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127};
128
129/**
130 * struct devfreq - Device devfreq structure
e09651fc 131 * @node: list node - contains the devices with devfreq that have been
a3c98b8b 132 * registered.
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133 * @lock: a mutex to protect accessing devfreq.
134 * @dev: device registered by devfreq class. dev.parent is the device
a3c98b8b 135 * using devfreq.
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136 * @profile: device-specific devfreq profile
137 * @governor: method how to choose frequency based on the usage.
1b5c1be2 138 * @governor_name: devfreq governor name for use with this devfreq
e09651fc 139 * @nb: notifier block used to notify devfreq object that it should
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140 * reevaluate operable frequencies. Devfreq users may use
141 * devfreq.nb to the corresponding register notifier call chain.
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142 * @work: delayed work for load monitoring.
143 * @previous_freq: previously configured frequency value.
144 * @data: Private data of the governor. The devfreq framework does not
a3c98b8b 145 * touch this.
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146 * @min_freq: Limit minimum frequency requested by user (0: none)
147 * @max_freq: Limit maximum frequency requested by user (0: none)
148 * @stop_polling: devfreq polling status of a device.
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149 * @total_trans: Number of devfreq transitions
150 * @trans_table: Statistics of devfreq transitions
151 * @time_in_state: Statistics of devfreq states
152 * @last_stat_updated: The last time stat updated
0fe3a664 153 * @transition_notifier_list: list head of DEVFREQ_TRANSITION_NOTIFIER notifier
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154 *
155 * This structure stores the devfreq information for a give device.
156 *
157 * Note that when a governor accesses entries in struct devfreq in its
158 * functions except for the context of callbacks defined in struct
159 * devfreq_governor, the governor should protect its access with the
160 * struct mutex lock in struct devfreq. A governor may use this mutex
161 * to protect its own private data in void *data as well.
162 */
163struct devfreq {
164 struct list_head node;
165
166 struct mutex lock;
167 struct device dev;
168 struct devfreq_dev_profile *profile;
169 const struct devfreq_governor *governor;
1b5c1be2 170 char governor_name[DEVFREQ_NAME_LEN];
a3c98b8b 171 struct notifier_block nb;
7e6fdd4b 172 struct delayed_work work;
a3c98b8b 173
a3c98b8b 174 unsigned long previous_freq;
08e75e75 175 struct devfreq_dev_status last_status;
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176
177 void *data; /* private data for governors */
178
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179 unsigned long min_freq;
180 unsigned long max_freq;
7e6fdd4b 181 bool stop_polling;
e552bbaf 182
0585123e 183 /* information for device frequency transition */
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184 unsigned int total_trans;
185 unsigned int *trans_table;
186 unsigned long *time_in_state;
187 unsigned long last_stat_updated;
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188
189 struct srcu_notifier_head transition_notifier_list;
190};
191
192struct devfreq_freqs {
193 unsigned long old;
194 unsigned long new;
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195};
196
197#if defined(CONFIG_PM_DEVFREQ)
198extern struct devfreq *devfreq_add_device(struct device *dev,
199 struct devfreq_dev_profile *profile,
1b5c1be2 200 const char *governor_name,
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201 void *data);
202extern int devfreq_remove_device(struct devfreq *devfreq);
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203extern struct devfreq *devm_devfreq_add_device(struct device *dev,
204 struct devfreq_dev_profile *profile,
205 const char *governor_name,
206 void *data);
207extern void devm_devfreq_remove_device(struct device *dev,
208 struct devfreq *devfreq);
de9c7394 209
464ed18e 210/* Supposed to be called by PM callbacks */
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211extern int devfreq_suspend_device(struct devfreq *devfreq);
212extern int devfreq_resume_device(struct devfreq *devfreq);
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213
214/* Helper functions for devfreq user device driver with OPP. */
47d43ba7 215extern struct dev_pm_opp *devfreq_recommended_opp(struct device *dev,
ab5f299f 216 unsigned long *freq, u32 flags);
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217extern int devfreq_register_opp_notifier(struct device *dev,
218 struct devfreq *devfreq);
219extern int devfreq_unregister_opp_notifier(struct device *dev,
220 struct devfreq *devfreq);
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221extern int devm_devfreq_register_opp_notifier(struct device *dev,
222 struct devfreq *devfreq);
223extern void devm_devfreq_unregister_opp_notifier(struct device *dev,
224 struct devfreq *devfreq);
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225extern int devfreq_register_notifier(struct devfreq *devfreq,
226 struct notifier_block *nb,
227 unsigned int list);
228extern int devfreq_unregister_notifier(struct devfreq *devfreq,
229 struct notifier_block *nb,
230 unsigned int list);
231extern int devm_devfreq_register_notifier(struct device *dev,
232 struct devfreq *devfreq,
233 struct notifier_block *nb,
234 unsigned int list);
235extern void devm_devfreq_unregister_notifier(struct device *dev,
236 struct devfreq *devfreq,
237 struct notifier_block *nb,
238 unsigned int list);
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239extern struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev,
240 int index);
241
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242/**
243 * devfreq_update_stats() - update the last_status pointer in struct devfreq
244 * @df: the devfreq instance whose status needs updating
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245 *
246 * Governors are recommended to use this function along with last_status,
247 * which allows other entities to reuse the last_status without affecting
248 * the values fetched later by governors.
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249 */
250static inline int devfreq_update_stats(struct devfreq *df)
251{
252 return df->profile->get_dev_status(df->dev.parent, &df->last_status);
253}
254
883d588e 255#if IS_ENABLED(CONFIG_DEVFREQ_GOV_SIMPLE_ONDEMAND)
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256/**
257 * struct devfreq_simple_ondemand_data - void *data fed to struct devfreq
258 * and devfreq_add_device
e09651fc 259 * @upthreshold: If the load is over this value, the frequency jumps.
ce26c5bb 260 * Specify 0 to use the default. Valid value = 0 to 100.
e09651fc 261 * @downdifferential: If the load is under upthreshold - downdifferential,
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262 * the governor may consider slowing the frequency down.
263 * Specify 0 to use the default. Valid value = 0 to 100.
264 * downdifferential < upthreshold must hold.
265 *
266 * If the fed devfreq_simple_ondemand_data pointer is NULL to the governor,
267 * the governor uses the default values.
268 */
269struct devfreq_simple_ondemand_data {
270 unsigned int upthreshold;
271 unsigned int downdifferential;
272};
273#endif
274
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275#if IS_ENABLED(CONFIG_DEVFREQ_GOV_PASSIVE)
276/**
277 * struct devfreq_passive_data - void *data fed to struct devfreq
278 * and devfreq_add_device
279 * @parent: the devfreq instance of parent device.
280 * @get_target_freq: Optional callback, Returns desired operating frequency
281 * for the device using passive governor. That is called
282 * when passive governor should decide the next frequency
283 * by using the new frequency of parent devfreq device
284 * using governors except for passive governor.
285 * If the devfreq device has the specific method to decide
286 * the next frequency, should use this callback.
287 * @this: the devfreq instance of own device.
288 * @nb: the notifier block for DEVFREQ_TRANSITION_NOTIFIER list
289 *
290 * The devfreq_passive_data have to set the devfreq instance of parent
291 * device with governors except for the passive governor. But, don't need to
292 * initialize the 'this' and 'nb' field because the devfreq core will handle
293 * them.
294 */
295struct devfreq_passive_data {
296 /* Should set the devfreq instance of parent device */
297 struct devfreq *parent;
298
299 /* Optional callback to decide the next frequency of passvice device */
300 int (*get_target_freq)(struct devfreq *this, unsigned long *freq);
301
302 /* For passive governor's internal use. Don't need to set them */
303 struct devfreq *this;
304 struct notifier_block nb;
305};
306#endif
307
a3c98b8b 308#else /* !CONFIG_PM_DEVFREQ */
5faaa035 309static inline struct devfreq *devfreq_add_device(struct device *dev,
a3c98b8b 310 struct devfreq_dev_profile *profile,
1b5c1be2 311 const char *governor_name,
a95e1f5d 312 void *data)
a3c98b8b 313{
8cd84092 314 return ERR_PTR(-ENOSYS);
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315}
316
5faaa035 317static inline int devfreq_remove_device(struct devfreq *devfreq)
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318{
319 return 0;
320}
321
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322static inline struct devfreq *devm_devfreq_add_device(struct device *dev,
323 struct devfreq_dev_profile *profile,
324 const char *governor_name,
325 void *data)
326{
327 return ERR_PTR(-ENOSYS);
328}
329
330static inline void devm_devfreq_remove_device(struct device *dev,
331 struct devfreq *devfreq)
332{
333}
334
5faaa035 335static inline int devfreq_suspend_device(struct devfreq *devfreq)
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336{
337 return 0;
338}
339
5faaa035 340static inline int devfreq_resume_device(struct devfreq *devfreq)
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341{
342 return 0;
343}
344
47d43ba7 345static inline struct dev_pm_opp *devfreq_recommended_opp(struct device *dev,
ab5f299f 346 unsigned long *freq, u32 flags)
a3c98b8b 347{
5faaa035 348 return ERR_PTR(-EINVAL);
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349}
350
5faaa035 351static inline int devfreq_register_opp_notifier(struct device *dev,
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352 struct devfreq *devfreq)
353{
354 return -EINVAL;
355}
356
5faaa035 357static inline int devfreq_unregister_opp_notifier(struct device *dev,
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358 struct devfreq *devfreq)
359{
360 return -EINVAL;
361}
362
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363static inline int devm_devfreq_register_opp_notifier(struct device *dev,
364 struct devfreq *devfreq)
365{
366 return -EINVAL;
367}
368
369static inline void devm_devfreq_unregister_opp_notifier(struct device *dev,
370 struct devfreq *devfreq)
371{
372}
08e75e75 373
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374static inline int devfreq_register_notifier(struct devfreq *devfreq,
375 struct notifier_block *nb,
376 unsigned int list)
377{
378 return 0;
379}
380
381static inline int devfreq_unregister_notifier(struct devfreq *devfreq,
382 struct notifier_block *nb,
383 unsigned int list)
384{
385 return 0;
386}
387
388static inline int devm_devfreq_register_notifier(struct device *dev,
389 struct devfreq *devfreq,
390 struct notifier_block *nb,
391 unsigned int list)
392{
393 return 0;
394}
395
396static inline void devm_devfreq_unregister_notifier(struct device *dev,
397 struct devfreq *devfreq,
398 struct notifier_block *nb,
399 unsigned int list)
400{
401}
402
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403static inline struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev,
404 int index)
405{
406 return ERR_PTR(-ENODEV);
407}
408
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409static inline int devfreq_update_stats(struct devfreq *df)
410{
411 return -EINVAL;
412}
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413#endif /* CONFIG_PM_DEVFREQ */
414
415#endif /* __LINUX_DEVFREQ_H__ */