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