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 /* DEVFREQ governor name */
19 #define DEVFREQ_GOV_SIMPLE_ONDEMAND "simple_ondemand"
20 #define DEVFREQ_GOV_PERFORMANCE "performance"
21 #define DEVFREQ_GOV_POWERSAVE "powersave"
22 #define DEVFREQ_GOV_USERSPACE "userspace"
23 #define DEVFREQ_GOV_PASSIVE "passive"
24
25 /* DEVFREQ notifier interface */
26 #define DEVFREQ_TRANSITION_NOTIFIER (0)
27
28 /* Transition notifiers of DEVFREQ_TRANSITION_NOTIFIER */
29 #define DEVFREQ_PRECHANGE (0)
30 #define DEVFREQ_POSTCHANGE (1)
31
32 /* DEVFREQ work timers */
33 enum devfreq_timer {
34 DEVFREQ_TIMER_DEFERRABLE = 0,
35 DEVFREQ_TIMER_DELAYED,
36 DEVFREQ_TIMER_NUM,
37 };
38
39 struct devfreq;
40 struct devfreq_governor;
41 struct devfreq_cpu_data;
42 struct thermal_cooling_device;
43
44 /**
45 * struct devfreq_dev_status - Data given from devfreq user device to
46 * governors. Represents the performance
47 * statistics.
48 * @total_time: The total time represented by this instance of
49 * devfreq_dev_status
50 * @busy_time: The time that the device was working among the
51 * total_time.
52 * @current_frequency: The operating frequency.
53 * @private_data: An entry not specified by the devfreq framework.
54 * A device and a specific governor may have their
55 * own protocol with private_data. However, because
56 * this is governor-specific, a governor using this
57 * will be only compatible with devices aware of it.
58 */
59 struct devfreq_dev_status {
60 /* both since the last measure */
61 unsigned long total_time;
62 unsigned long busy_time;
63 unsigned long current_frequency;
64 void *private_data;
65 };
66
67 /*
68 * The resulting frequency should be at most this. (this bound is the
69 * least upper bound; thus, the resulting freq should be lower or same)
70 * If the flag is not set, the resulting frequency should be at most the
71 * bound (greatest lower bound)
72 */
73 #define DEVFREQ_FLAG_LEAST_UPPER_BOUND 0x1
74
75 /**
76 * struct devfreq_dev_profile - Devfreq's user device profile
77 * @initial_freq: The operating frequency when devfreq_add_device() is
78 * called.
79 * @polling_ms: The polling interval in ms. 0 disables polling.
80 * @timer: Timer type is either deferrable or delayed timer.
81 * @target: The device should set its operating frequency at
82 * freq or lowest-upper-than-freq value. If freq is
83 * higher than any operable frequency, set maximum.
84 * Before returning, target function should set
85 * freq at the current frequency.
86 * The "flags" parameter's possible values are
87 * explained above with "DEVFREQ_FLAG_*" macros.
88 * @get_dev_status: The device should provide the current performance
89 * status to devfreq. Governors are recommended not to
90 * use this directly. Instead, governors are recommended
91 * to use devfreq_update_stats() along with
92 * devfreq.last_status.
93 * @get_cur_freq: The device should provide the current frequency
94 * at which it is operating.
95 * @exit: An optional callback that is called when devfreq
96 * is removing the devfreq object due to error or
97 * from devfreq_remove_device() call. If the user
98 * has registered devfreq->nb at a notifier-head,
99 * this is the time to unregister it.
100 * @freq_table: Optional list of frequencies to support statistics
101 * and freq_table must be generated in ascending order.
102 * @max_state: The size of freq_table.
103 *
104 * @is_cooling_device: A self-explanatory boolean giving the device a
105 * cooling effect property.
106 */
107 struct devfreq_dev_profile {
108 unsigned long initial_freq;
109 unsigned int polling_ms;
110 enum devfreq_timer timer;
111
112 int (*target)(struct device *dev, unsigned long *freq, u32 flags);
113 int (*get_dev_status)(struct device *dev,
114 struct devfreq_dev_status *stat);
115 int (*get_cur_freq)(struct device *dev, unsigned long *freq);
116 void (*exit)(struct device *dev);
117
118 unsigned long *freq_table;
119 unsigned int max_state;
120
121 bool is_cooling_device;
122 };
123
124 /**
125 * struct devfreq_stats - Statistics of devfreq device behavior
126 * @total_trans: Number of devfreq transitions.
127 * @trans_table: Statistics of devfreq transitions.
128 * @time_in_state: Statistics of devfreq states.
129 * @last_update: The last time stats were updated.
130 */
131 struct devfreq_stats {
132 unsigned int total_trans;
133 unsigned int *trans_table;
134 u64 *time_in_state;
135 u64 last_update;
136 };
137
138 /**
139 * struct devfreq - Device devfreq structure
140 * @node: list node - contains the devices with devfreq that have been
141 * registered.
142 * @lock: a mutex to protect accessing devfreq.
143 * @dev: device registered by devfreq class. dev.parent is the device
144 * using devfreq.
145 * @profile: device-specific devfreq profile
146 * @governor: method how to choose frequency based on the usage.
147 * @opp_table: Reference to OPP table of dev.parent, if one exists.
148 * @nb: notifier block used to notify devfreq object that it should
149 * reevaluate operable frequencies. Devfreq users may use
150 * devfreq.nb to the corresponding register notifier call chain.
151 * @work: delayed work for load monitoring.
152 * @freq_table: current frequency table used by the devfreq driver.
153 * @max_state: count of entry present in the frequency table.
154 * @previous_freq: previously configured frequency value.
155 * @last_status: devfreq user device info, performance statistics
156 * @data: devfreq driver pass to governors, governor should not change it.
157 * @governor_data: private data for governors, devfreq core doesn't touch it.
158 * @user_min_freq_req: PM QoS minimum frequency request from user (via sysfs)
159 * @user_max_freq_req: PM QoS maximum frequency request from user (via sysfs)
160 * @scaling_min_freq: Limit minimum frequency requested by OPP interface
161 * @scaling_max_freq: Limit maximum frequency requested by OPP interface
162 * @stop_polling: devfreq polling status of a device.
163 * @suspend_freq: frequency of a device set during suspend phase.
164 * @resume_freq: frequency of a device set in resume phase.
165 * @suspend_count: suspend requests counter for a device.
166 * @stats: Statistics of devfreq device behavior
167 * @transition_notifier_list: list head of DEVFREQ_TRANSITION_NOTIFIER notifier
168 * @cdev: Cooling device pointer if the devfreq has cooling property
169 * @nb_min: Notifier block for DEV_PM_QOS_MIN_FREQUENCY
170 * @nb_max: Notifier block for DEV_PM_QOS_MAX_FREQUENCY
171 *
172 * This structure stores the devfreq information for a given device.
173 *
174 * Note that when a governor accesses entries in struct devfreq in its
175 * functions except for the context of callbacks defined in struct
176 * devfreq_governor, the governor should protect its access with the
177 * struct mutex lock in struct devfreq. A governor may use this mutex
178 * to protect its own private data in ``void *data`` as well.
179 */
180 struct devfreq {
181 struct list_head node;
182
183 struct mutex lock;
184 struct device dev;
185 struct devfreq_dev_profile *profile;
186 const struct devfreq_governor *governor;
187 struct opp_table *opp_table;
188 struct notifier_block nb;
189 struct delayed_work work;
190
191 unsigned long *freq_table;
192 unsigned int max_state;
193
194 unsigned long previous_freq;
195 struct devfreq_dev_status last_status;
196
197 void *data;
198 void *governor_data;
199
200 struct dev_pm_qos_request user_min_freq_req;
201 struct dev_pm_qos_request user_max_freq_req;
202 unsigned long scaling_min_freq;
203 unsigned long scaling_max_freq;
204 bool stop_polling;
205
206 unsigned long suspend_freq;
207 unsigned long resume_freq;
208 atomic_t suspend_count;
209
210 /* information for device frequency transitions */
211 struct devfreq_stats stats;
212
213 struct srcu_notifier_head transition_notifier_list;
214
215 /* Pointer to the cooling device if used for thermal mitigation */
216 struct thermal_cooling_device *cdev;
217
218 struct notifier_block nb_min;
219 struct notifier_block nb_max;
220 };
221
222 struct devfreq_freqs {
223 unsigned long old;
224 unsigned long new;
225 };
226
227 #if defined(CONFIG_PM_DEVFREQ)
228 struct devfreq *devfreq_add_device(struct device *dev,
229 struct devfreq_dev_profile *profile,
230 const char *governor_name,
231 void *data);
232 int devfreq_remove_device(struct devfreq *devfreq);
233 struct devfreq *devm_devfreq_add_device(struct device *dev,
234 struct devfreq_dev_profile *profile,
235 const char *governor_name,
236 void *data);
237 void devm_devfreq_remove_device(struct device *dev, struct devfreq *devfreq);
238
239 /* Supposed to be called by PM callbacks */
240 int devfreq_suspend_device(struct devfreq *devfreq);
241 int devfreq_resume_device(struct devfreq *devfreq);
242
243 void devfreq_suspend(void);
244 void devfreq_resume(void);
245
246 /* update_devfreq() - Reevaluate the device and configure frequency */
247 int update_devfreq(struct devfreq *devfreq);
248
249 /* Helper functions for devfreq user device driver with OPP. */
250 struct dev_pm_opp *devfreq_recommended_opp(struct device *dev,
251 unsigned long *freq, u32 flags);
252 int devfreq_register_opp_notifier(struct device *dev,
253 struct devfreq *devfreq);
254 int devfreq_unregister_opp_notifier(struct device *dev,
255 struct devfreq *devfreq);
256 int devm_devfreq_register_opp_notifier(struct device *dev,
257 struct devfreq *devfreq);
258 void devm_devfreq_unregister_opp_notifier(struct device *dev,
259 struct devfreq *devfreq);
260 int devfreq_register_notifier(struct devfreq *devfreq,
261 struct notifier_block *nb,
262 unsigned int list);
263 int devfreq_unregister_notifier(struct devfreq *devfreq,
264 struct notifier_block *nb,
265 unsigned int list);
266 int devm_devfreq_register_notifier(struct device *dev,
267 struct devfreq *devfreq,
268 struct notifier_block *nb,
269 unsigned int list);
270 void devm_devfreq_unregister_notifier(struct device *dev,
271 struct devfreq *devfreq,
272 struct notifier_block *nb,
273 unsigned int list);
274 struct devfreq *devfreq_get_devfreq_by_node(struct device_node *node);
275 struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev,
276 const char *phandle_name, int index);
277 #endif /* CONFIG_PM_DEVFREQ */
278
279 /**
280 * struct devfreq_simple_ondemand_data - ``void *data`` fed to struct devfreq
281 * and devfreq_add_device
282 * @upthreshold: If the load is over this value, the frequency jumps.
283 * Specify 0 to use the default. Valid value = 0 to 100.
284 * @downdifferential: If the load is under upthreshold - downdifferential,
285 * the governor may consider slowing the frequency down.
286 * Specify 0 to use the default. Valid value = 0 to 100.
287 * downdifferential < upthreshold must hold.
288 *
289 * If the fed devfreq_simple_ondemand_data pointer is NULL to the governor,
290 * the governor uses the default values.
291 */
292 struct devfreq_simple_ondemand_data {
293 unsigned int upthreshold;
294 unsigned int downdifferential;
295 };
296
297 enum devfreq_parent_dev_type {
298 DEVFREQ_PARENT_DEV,
299 CPUFREQ_PARENT_DEV,
300 };
301
302 /**
303 * struct devfreq_passive_data - ``void *data`` fed to struct devfreq
304 * and devfreq_add_device
305 * @parent: the devfreq instance of parent device.
306 * @get_target_freq: Optional callback, Returns desired operating frequency
307 * for the device using passive governor. That is called
308 * when passive governor should decide the next frequency
309 * by using the new frequency of parent devfreq device
310 * using governors except for passive governor.
311 * If the devfreq device has the specific method to decide
312 * the next frequency, should use this callback.
313 * @parent_type: the parent type of the device.
314 * @this: the devfreq instance of own device.
315 * @nb: the notifier block for DEVFREQ_TRANSITION_NOTIFIER or
316 * CPUFREQ_TRANSITION_NOTIFIER list.
317 * @cpu_data_list: the list of cpu frequency data for all cpufreq_policy.
318 *
319 * The devfreq_passive_data have to set the devfreq instance of parent
320 * device with governors except for the passive governor. But, don't need to
321 * initialize the 'this' and 'nb' field because the devfreq core will handle
322 * them.
323 */
324 struct devfreq_passive_data {
325 /* Should set the devfreq instance of parent device */
326 struct devfreq *parent;
327
328 /* Optional callback to decide the next frequency of passvice device */
329 int (*get_target_freq)(struct devfreq *this, unsigned long *freq);
330
331 /* Should set the type of parent device */
332 enum devfreq_parent_dev_type parent_type;
333
334 /* For passive governor's internal use. Don't need to set them */
335 struct devfreq *this;
336 struct notifier_block nb;
337 struct list_head cpu_data_list;
338 };
339
340 #if !defined(CONFIG_PM_DEVFREQ)
341 static inline struct devfreq *devfreq_add_device(struct device *dev,
342 struct devfreq_dev_profile *profile,
343 const char *governor_name,
344 void *data)
345 {
346 return ERR_PTR(-ENOSYS);
347 }
348
349 static inline int devfreq_remove_device(struct devfreq *devfreq)
350 {
351 return 0;
352 }
353
354 static inline struct devfreq *devm_devfreq_add_device(struct device *dev,
355 struct devfreq_dev_profile *profile,
356 const char *governor_name,
357 void *data)
358 {
359 return ERR_PTR(-ENOSYS);
360 }
361
362 static inline void devm_devfreq_remove_device(struct device *dev,
363 struct devfreq *devfreq)
364 {
365 }
366
367 static inline int devfreq_suspend_device(struct devfreq *devfreq)
368 {
369 return 0;
370 }
371
372 static inline int devfreq_resume_device(struct devfreq *devfreq)
373 {
374 return 0;
375 }
376
377 static inline void devfreq_suspend(void) {}
378 static inline void devfreq_resume(void) {}
379
380 static inline struct dev_pm_opp *devfreq_recommended_opp(struct device *dev,
381 unsigned long *freq, u32 flags)
382 {
383 return ERR_PTR(-EINVAL);
384 }
385
386 static inline int devfreq_register_opp_notifier(struct device *dev,
387 struct devfreq *devfreq)
388 {
389 return -EINVAL;
390 }
391
392 static inline int devfreq_unregister_opp_notifier(struct device *dev,
393 struct devfreq *devfreq)
394 {
395 return -EINVAL;
396 }
397
398 static inline int devm_devfreq_register_opp_notifier(struct device *dev,
399 struct devfreq *devfreq)
400 {
401 return -EINVAL;
402 }
403
404 static inline void devm_devfreq_unregister_opp_notifier(struct device *dev,
405 struct devfreq *devfreq)
406 {
407 }
408
409 static inline int devfreq_register_notifier(struct devfreq *devfreq,
410 struct notifier_block *nb,
411 unsigned int list)
412 {
413 return 0;
414 }
415
416 static inline int devfreq_unregister_notifier(struct devfreq *devfreq,
417 struct notifier_block *nb,
418 unsigned int list)
419 {
420 return 0;
421 }
422
423 static inline int devm_devfreq_register_notifier(struct device *dev,
424 struct devfreq *devfreq,
425 struct notifier_block *nb,
426 unsigned int list)
427 {
428 return 0;
429 }
430
431 static inline void devm_devfreq_unregister_notifier(struct device *dev,
432 struct devfreq *devfreq,
433 struct notifier_block *nb,
434 unsigned int list)
435 {
436 }
437
438 static inline struct devfreq *devfreq_get_devfreq_by_node(struct device_node *node)
439 {
440 return ERR_PTR(-ENODEV);
441 }
442
443 static inline struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev,
444 const char *phandle_name, int index)
445 {
446 return ERR_PTR(-ENODEV);
447 }
448
449 static inline int devfreq_update_stats(struct devfreq *df)
450 {
451 return -EINVAL;
452 }
453 #endif /* CONFIG_PM_DEVFREQ */
454
455 #endif /* __LINUX_DEVFREQ_H__ */
456
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