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1 : : /* SPDX-License-Identifier: GPL-2.0-only */
2 : : /*
3 : : * devfreq: Generic Dynamic Voltage and Frequency Scaling (DVFS) Framework
4 : : * for Non-CPU Devices.
5 : : *
6 : : * Copyright (C) 2011 Samsung Electronics
7 : : * MyungJoo Ham <myungjoo.ham@samsung.com>
8 : : */
9 : :
10 : : #ifndef __LINUX_DEVFREQ_H__
11 : : #define __LINUX_DEVFREQ_H__
12 : :
13 : : #include <linux/device.h>
14 : : #include <linux/notifier.h>
15 : : #include <linux/pm_opp.h>
16 : : #include <linux/pm_qos.h>
17 : :
18 : : #define DEVFREQ_NAME_LEN 16
19 : :
20 : : /* DEVFREQ governor name */
21 : : #define DEVFREQ_GOV_SIMPLE_ONDEMAND "simple_ondemand"
22 : : #define DEVFREQ_GOV_PERFORMANCE "performance"
23 : : #define DEVFREQ_GOV_POWERSAVE "powersave"
24 : : #define DEVFREQ_GOV_USERSPACE "userspace"
25 : : #define DEVFREQ_GOV_PASSIVE "passive"
26 : :
27 : : /* DEVFREQ notifier interface */
28 : : #define DEVFREQ_TRANSITION_NOTIFIER (0)
29 : :
30 : : /* Transition notifiers of DEVFREQ_TRANSITION_NOTIFIER */
31 : : #define DEVFREQ_PRECHANGE (0)
32 : : #define DEVFREQ_POSTCHANGE (1)
33 : :
34 : : struct devfreq;
35 : : struct devfreq_governor;
36 : :
37 : : /**
38 : : * struct devfreq_dev_status - Data given from devfreq user device to
39 : : * governors. Represents the performance
40 : : * statistics.
41 : : * @total_time: The total time represented by this instance of
42 : : * devfreq_dev_status
43 : : * @busy_time: The time that the device was working among the
44 : : * total_time.
45 : : * @current_frequency: The operating frequency.
46 : : * @private_data: An entry not specified by the devfreq framework.
47 : : * A device and a specific governor may have their
48 : : * own protocol with private_data. However, because
49 : : * this is governor-specific, a governor using this
50 : : * will be only compatible with devices aware of it.
51 : : */
52 : : struct devfreq_dev_status {
53 : : /* both since the last measure */
54 : : unsigned long total_time;
55 : : unsigned long busy_time;
56 : : unsigned long current_frequency;
57 : : void *private_data;
58 : : };
59 : :
60 : : /*
61 : : * The resulting frequency should be at most this. (this bound is the
62 : : * least upper bound; thus, the resulting freq should be lower or same)
63 : : * If the flag is not set, the resulting frequency should be at most the
64 : : * bound (greatest lower bound)
65 : : */
66 : : #define DEVFREQ_FLAG_LEAST_UPPER_BOUND 0x1
67 : :
68 : : /**
69 : : * struct devfreq_dev_profile - Devfreq's user device profile
70 : : * @initial_freq: The operating frequency when devfreq_add_device() is
71 : : * called.
72 : : * @polling_ms: The polling interval in ms. 0 disables polling.
73 : : * @target: The device should set its operating frequency at
74 : : * freq or lowest-upper-than-freq value. If freq is
75 : : * higher than any operable frequency, set maximum.
76 : : * Before returning, target function should set
77 : : * freq at the current frequency.
78 : : * The "flags" parameter's possible values are
79 : : * explained above with "DEVFREQ_FLAG_*" macros.
80 : : * @get_dev_status: The device should provide the current performance
81 : : * status to devfreq. Governors are recommended not to
82 : : * use this directly. Instead, governors are recommended
83 : : * to use devfreq_update_stats() along with
84 : : * devfreq.last_status.
85 : : * @get_cur_freq: The device should provide the current frequency
86 : : * at which it is operating.
87 : : * @exit: An optional callback that is called when devfreq
88 : : * is removing the devfreq object due to error or
89 : : * from devfreq_remove_device() call. If the user
90 : : * has registered devfreq->nb at a notifier-head,
91 : : * this is the time to unregister it.
92 : : * @freq_table: Optional list of frequencies to support statistics
93 : : * and freq_table must be generated in ascending order.
94 : : * @max_state: The size of freq_table.
95 : : */
96 : : struct devfreq_dev_profile {
97 : : unsigned long initial_freq;
98 : : unsigned int polling_ms;
99 : :
100 : : int (*target)(struct device *dev, unsigned long *freq, u32 flags);
101 : : int (*get_dev_status)(struct device *dev,
102 : : struct devfreq_dev_status *stat);
103 : : int (*get_cur_freq)(struct device *dev, unsigned long *freq);
104 : : void (*exit)(struct device *dev);
105 : :
106 : : unsigned long *freq_table;
107 : : unsigned int max_state;
108 : : };
109 : :
110 : : /**
111 : : * struct devfreq_stats - Statistics of devfreq device behavior
112 : : * @total_trans: Number of devfreq transitions.
113 : : * @trans_table: Statistics of devfreq transitions.
114 : : * @time_in_state: Statistics of devfreq states.
115 : : * @last_update: The last time stats were updated.
116 : : */
117 : : struct devfreq_stats {
118 : : unsigned int total_trans;
119 : : unsigned int *trans_table;
120 : : u64 *time_in_state;
121 : : u64 last_update;
122 : : };
123 : :
124 : : /**
125 : : * struct devfreq - Device devfreq structure
126 : : * @node: list node - contains the devices with devfreq that have been
127 : : * registered.
128 : : * @lock: a mutex to protect accessing devfreq.
129 : : * @dev: device registered by devfreq class. dev.parent is the device
130 : : * using devfreq.
131 : : * @profile: device-specific devfreq profile
132 : : * @governor: method how to choose frequency based on the usage.
133 : : * @governor_name: devfreq governor name for use with this devfreq
134 : : * @nb: notifier block used to notify devfreq object that it should
135 : : * reevaluate operable frequencies. Devfreq users may use
136 : : * devfreq.nb to the corresponding register notifier call chain.
137 : : * @work: delayed work for load monitoring.
138 : : * @previous_freq: previously configured frequency value.
139 : : * @last_status: devfreq user device info, performance statistics
140 : : * @data: Private data of the governor. The devfreq framework does not
141 : : * touch this.
142 : : * @user_min_freq_req: PM QoS minimum frequency request from user (via sysfs)
143 : : * @user_max_freq_req: PM QoS maximum frequency request from user (via sysfs)
144 : : * @scaling_min_freq: Limit minimum frequency requested by OPP interface
145 : : * @scaling_max_freq: Limit maximum frequency requested by OPP interface
146 : : * @stop_polling: devfreq polling status of a device.
147 : : * @suspend_freq: frequency of a device set during suspend phase.
148 : : * @resume_freq: frequency of a device set in resume phase.
149 : : * @suspend_count: suspend requests counter for a device.
150 : : * @stats: Statistics of devfreq device behavior
151 : : * @transition_notifier_list: list head of DEVFREQ_TRANSITION_NOTIFIER notifier
152 : : * @nb_min: Notifier block for DEV_PM_QOS_MIN_FREQUENCY
153 : : * @nb_max: Notifier block for DEV_PM_QOS_MAX_FREQUENCY
154 : : *
155 : : * This structure stores the devfreq information for a given 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 : : */
163 : : struct 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;
170 : : char governor_name[DEVFREQ_NAME_LEN];
171 : : struct notifier_block nb;
172 : : struct delayed_work work;
173 : :
174 : : unsigned long previous_freq;
175 : : struct devfreq_dev_status last_status;
176 : :
177 : : void *data; /* private data for governors */
178 : :
179 : : struct dev_pm_qos_request user_min_freq_req;
180 : : struct dev_pm_qos_request user_max_freq_req;
181 : : unsigned long scaling_min_freq;
182 : : unsigned long scaling_max_freq;
183 : : bool stop_polling;
184 : :
185 : : unsigned long suspend_freq;
186 : : unsigned long resume_freq;
187 : : atomic_t suspend_count;
188 : :
189 : : /* information for device frequency transitions */
190 : : struct devfreq_stats stats;
191 : :
192 : : struct srcu_notifier_head transition_notifier_list;
193 : :
194 : : struct notifier_block nb_min;
195 : : struct notifier_block nb_max;
196 : : };
197 : :
198 : : struct devfreq_freqs {
199 : : unsigned long old;
200 : : unsigned long new;
201 : : };
202 : :
203 : : #if defined(CONFIG_PM_DEVFREQ)
204 : : extern struct devfreq *devfreq_add_device(struct device *dev,
205 : : struct devfreq_dev_profile *profile,
206 : : const char *governor_name,
207 : : void *data);
208 : : extern int devfreq_remove_device(struct devfreq *devfreq);
209 : : extern struct devfreq *devm_devfreq_add_device(struct device *dev,
210 : : struct devfreq_dev_profile *profile,
211 : : const char *governor_name,
212 : : void *data);
213 : : extern void devm_devfreq_remove_device(struct device *dev,
214 : : struct devfreq *devfreq);
215 : :
216 : : /* Supposed to be called by PM callbacks */
217 : : extern int devfreq_suspend_device(struct devfreq *devfreq);
218 : : extern int devfreq_resume_device(struct devfreq *devfreq);
219 : :
220 : : extern void devfreq_suspend(void);
221 : : extern void devfreq_resume(void);
222 : :
223 : : /**
224 : : * update_devfreq() - Reevaluate the device and configure frequency
225 : : * @devfreq: the devfreq device
226 : : *
227 : : * Note: devfreq->lock must be held
228 : : */
229 : : extern int update_devfreq(struct devfreq *devfreq);
230 : :
231 : : /* Helper functions for devfreq user device driver with OPP. */
232 : : extern struct dev_pm_opp *devfreq_recommended_opp(struct device *dev,
233 : : unsigned long *freq, u32 flags);
234 : : extern int devfreq_register_opp_notifier(struct device *dev,
235 : : struct devfreq *devfreq);
236 : : extern int devfreq_unregister_opp_notifier(struct device *dev,
237 : : struct devfreq *devfreq);
238 : : extern int devm_devfreq_register_opp_notifier(struct device *dev,
239 : : struct devfreq *devfreq);
240 : : extern void devm_devfreq_unregister_opp_notifier(struct device *dev,
241 : : struct devfreq *devfreq);
242 : : extern int devfreq_register_notifier(struct devfreq *devfreq,
243 : : struct notifier_block *nb,
244 : : unsigned int list);
245 : : extern int devfreq_unregister_notifier(struct devfreq *devfreq,
246 : : struct notifier_block *nb,
247 : : unsigned int list);
248 : : extern int devm_devfreq_register_notifier(struct device *dev,
249 : : struct devfreq *devfreq,
250 : : struct notifier_block *nb,
251 : : unsigned int list);
252 : : extern void devm_devfreq_unregister_notifier(struct device *dev,
253 : : struct devfreq *devfreq,
254 : : struct notifier_block *nb,
255 : : unsigned int list);
256 : : extern struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev,
257 : : int index);
258 : :
259 : : #if IS_ENABLED(CONFIG_DEVFREQ_GOV_SIMPLE_ONDEMAND)
260 : : /**
261 : : * struct devfreq_simple_ondemand_data - void *data fed to struct devfreq
262 : : * and devfreq_add_device
263 : : * @upthreshold: If the load is over this value, the frequency jumps.
264 : : * Specify 0 to use the default. Valid value = 0 to 100.
265 : : * @downdifferential: If the load is under upthreshold - downdifferential,
266 : : * the governor may consider slowing the frequency down.
267 : : * Specify 0 to use the default. Valid value = 0 to 100.
268 : : * downdifferential < upthreshold must hold.
269 : : *
270 : : * If the fed devfreq_simple_ondemand_data pointer is NULL to the governor,
271 : : * the governor uses the default values.
272 : : */
273 : : struct devfreq_simple_ondemand_data {
274 : : unsigned int upthreshold;
275 : : unsigned int downdifferential;
276 : : };
277 : : #endif
278 : :
279 : : #if IS_ENABLED(CONFIG_DEVFREQ_GOV_PASSIVE)
280 : : /**
281 : : * struct devfreq_passive_data - void *data fed to struct devfreq
282 : : * and devfreq_add_device
283 : : * @parent: the devfreq instance of parent device.
284 : : * @get_target_freq: Optional callback, Returns desired operating frequency
285 : : * for the device using passive governor. That is called
286 : : * when passive governor should decide the next frequency
287 : : * by using the new frequency of parent devfreq device
288 : : * using governors except for passive governor.
289 : : * If the devfreq device has the specific method to decide
290 : : * the next frequency, should use this callback.
291 : : * @this: the devfreq instance of own device.
292 : : * @nb: the notifier block for DEVFREQ_TRANSITION_NOTIFIER list
293 : : *
294 : : * The devfreq_passive_data have to set the devfreq instance of parent
295 : : * device with governors except for the passive governor. But, don't need to
296 : : * initialize the 'this' and 'nb' field because the devfreq core will handle
297 : : * them.
298 : : */
299 : : struct devfreq_passive_data {
300 : : /* Should set the devfreq instance of parent device */
301 : : struct devfreq *parent;
302 : :
303 : : /* Optional callback to decide the next frequency of passvice device */
304 : : int (*get_target_freq)(struct devfreq *this, unsigned long *freq);
305 : :
306 : : /* For passive governor's internal use. Don't need to set them */
307 : : struct devfreq *this;
308 : : struct notifier_block nb;
309 : : };
310 : : #endif
311 : :
312 : : #else /* !CONFIG_PM_DEVFREQ */
313 : : static inline struct devfreq *devfreq_add_device(struct device *dev,
314 : : struct devfreq_dev_profile *profile,
315 : : const char *governor_name,
316 : : void *data)
317 : : {
318 : : return ERR_PTR(-ENOSYS);
319 : : }
320 : :
321 : : static inline int devfreq_remove_device(struct devfreq *devfreq)
322 : : {
323 : : return 0;
324 : : }
325 : :
326 : : static inline struct devfreq *devm_devfreq_add_device(struct device *dev,
327 : : struct devfreq_dev_profile *profile,
328 : : const char *governor_name,
329 : : void *data)
330 : : {
331 : : return ERR_PTR(-ENOSYS);
332 : : }
333 : :
334 : : static inline void devm_devfreq_remove_device(struct device *dev,
335 : : struct devfreq *devfreq)
336 : : {
337 : : }
338 : :
339 : : static inline int devfreq_suspend_device(struct devfreq *devfreq)
340 : : {
341 : : return 0;
342 : : }
343 : :
344 : : static inline int devfreq_resume_device(struct devfreq *devfreq)
345 : : {
346 : : return 0;
347 : : }
348 : :
349 : 0 : static inline void devfreq_suspend(void) {}
350 : 0 : static inline void devfreq_resume(void) {}
351 : :
352 : : static inline struct dev_pm_opp *devfreq_recommended_opp(struct device *dev,
353 : : unsigned long *freq, u32 flags)
354 : : {
355 : : return ERR_PTR(-EINVAL);
356 : : }
357 : :
358 : : static inline int devfreq_register_opp_notifier(struct device *dev,
359 : : struct devfreq *devfreq)
360 : : {
361 : : return -EINVAL;
362 : : }
363 : :
364 : : static inline int devfreq_unregister_opp_notifier(struct device *dev,
365 : : struct devfreq *devfreq)
366 : : {
367 : : return -EINVAL;
368 : : }
369 : :
370 : : static inline int devm_devfreq_register_opp_notifier(struct device *dev,
371 : : struct devfreq *devfreq)
372 : : {
373 : : return -EINVAL;
374 : : }
375 : :
376 : : static inline void devm_devfreq_unregister_opp_notifier(struct device *dev,
377 : : struct devfreq *devfreq)
378 : : {
379 : : }
380 : :
381 : : static inline int devfreq_register_notifier(struct devfreq *devfreq,
382 : : struct notifier_block *nb,
383 : : unsigned int list)
384 : : {
385 : : return 0;
386 : : }
387 : :
388 : : static inline int devfreq_unregister_notifier(struct devfreq *devfreq,
389 : : struct notifier_block *nb,
390 : : unsigned int list)
391 : : {
392 : : return 0;
393 : : }
394 : :
395 : : static inline int devm_devfreq_register_notifier(struct device *dev,
396 : : struct devfreq *devfreq,
397 : : struct notifier_block *nb,
398 : : unsigned int list)
399 : : {
400 : : return 0;
401 : : }
402 : :
403 : : static inline void devm_devfreq_unregister_notifier(struct device *dev,
404 : : struct devfreq *devfreq,
405 : : struct notifier_block *nb,
406 : : unsigned int list)
407 : : {
408 : : }
409 : :
410 : : static inline struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev,
411 : : int index)
412 : : {
413 : : return ERR_PTR(-ENODEV);
414 : : }
415 : :
416 : : static inline int devfreq_update_stats(struct devfreq *df)
417 : : {
418 : : return -EINVAL;
419 : : }
420 : : #endif /* CONFIG_PM_DEVFREQ */
421 : :
422 : : #endif /* __LINUX_DEVFREQ_H__ */
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