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