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