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