1 /* SPDX-License-Identifier: GPL-2.0-only */
3 * devfreq: Generic Dynamic Voltage and Frequency Scaling (DVFS) Framework
6 * Copyright (C) 2011 Samsung Electronics
7 * MyungJoo Ham <myungjoo.ham@samsung.com>
10 #ifndef __LINUX_DEVFREQ_H__
11 #define __LINUX_DEVFREQ_H__
13 #include <linux/device.h>
14 #include <linux/notifier.h>
15 #include <linux/pm_opp.h>
16 #include <linux/pm_qos.h>
18 #define DEVFREQ_NAME_LEN 16
20 /* DEVFREQ governor name */
21 #define DEVFREQ_GOV_SIMPLE_ONDEMAND "simple_ondemand"
22 #define DEVFREQ_GOV_PERFORMANCE "performance"
23 #define DEVFREQ_GOV_POWERSAVE "powersave"
24 #define DEVFREQ_GOV_USERSPACE "userspace"
25 #define DEVFREQ_GOV_PASSIVE "passive"
27 /* DEVFREQ notifier interface */
28 #define DEVFREQ_TRANSITION_NOTIFIER (0)
30 /* Transition notifiers of DEVFREQ_TRANSITION_NOTIFIER */
31 #define DEVFREQ_PRECHANGE (0)
32 #define DEVFREQ_POSTCHANGE (1)
35 struct devfreq_governor;
38 * struct devfreq_dev_status - Data given from devfreq user device to
39 * governors. Represents the performance
41 * @total_time: The total time represented by this instance of
43 * @busy_time: The time that the device was working among the
45 * @current_frequency: The operating frequency.
46 * @private_data: An entry not specified by the devfreq framework.
47 * A device and a specific governor may have their
48 * own protocol with private_data. However, because
49 * this is governor-specific, a governor using this
50 * will be only compatible with devices aware of it.
52 struct devfreq_dev_status {
53 /* both since the last measure */
54 unsigned long total_time;
55 unsigned long busy_time;
56 unsigned long current_frequency;
61 * The resulting frequency should be at most this. (this bound is the
62 * least upper bound; thus, the resulting freq should be lower or same)
63 * If the flag is not set, the resulting frequency should be at most the
64 * bound (greatest lower bound)
66 #define DEVFREQ_FLAG_LEAST_UPPER_BOUND 0x1
69 * struct devfreq_dev_profile - Devfreq's user device profile
70 * @initial_freq: The operating frequency when devfreq_add_device() is
72 * @polling_ms: The polling interval in ms. 0 disables polling.
73 * @target: The device should set its operating frequency at
74 * freq or lowest-upper-than-freq value. If freq is
75 * higher than any operable frequency, set maximum.
76 * Before returning, target function should set
77 * freq at the current frequency.
78 * The "flags" parameter's possible values are
79 * explained above with "DEVFREQ_FLAG_*" macros.
80 * @get_dev_status: The device should provide the current performance
81 * status to devfreq. Governors are recommended not to
82 * use this directly. Instead, governors are recommended
83 * to use devfreq_update_stats() along with
84 * devfreq.last_status.
85 * @get_cur_freq: The device should provide the current frequency
86 * at which it is operating.
87 * @exit: An optional callback that is called when devfreq
88 * is removing the devfreq object due to error or
89 * from devfreq_remove_device() call. If the user
90 * has registered devfreq->nb at a notifier-head,
91 * this is the time to unregister it.
92 * @freq_table: Optional list of frequencies to support statistics
93 * and freq_table must be generated in ascending order.
94 * @max_state: The size of freq_table.
96 struct devfreq_dev_profile {
97 unsigned long initial_freq;
98 unsigned int polling_ms;
100 int (*target)(struct device *dev, unsigned long *freq, u32 flags);
101 int (*get_dev_status)(struct device *dev,
102 struct devfreq_dev_status *stat);
103 int (*get_cur_freq)(struct device *dev, unsigned long *freq);
104 void (*exit)(struct device *dev);
106 unsigned long *freq_table;
107 unsigned int max_state;
111 * struct devfreq_stats - Statistics of devfreq device behavior
112 * @total_trans: Number of devfreq transitions.
113 * @trans_table: Statistics of devfreq transitions.
114 * @time_in_state: Statistics of devfreq states.
115 * @last_update: The last time stats were updated.
117 struct devfreq_stats {
118 unsigned int total_trans;
119 unsigned int *trans_table;
125 * struct devfreq - Device devfreq structure
126 * @node: list node - contains the devices with devfreq that have been
128 * @lock: a mutex to protect accessing devfreq.
129 * @dev: device registered by devfreq class. dev.parent is the device
131 * @profile: device-specific devfreq profile
132 * @governor: method how to choose frequency based on the usage.
133 * @governor_name: devfreq governor name for use with this devfreq
134 * @nb: notifier block used to notify devfreq object that it should
135 * reevaluate operable frequencies. Devfreq users may use
136 * devfreq.nb to the corresponding register notifier call chain.
137 * @work: delayed work for load monitoring.
138 * @previous_freq: previously configured frequency value.
139 * @last_status: devfreq user device info, performance statistics
140 * @data: Private data of the governor. The devfreq framework does not
142 * @user_min_freq_req: PM QoS minimum frequency request from user (via sysfs)
143 * @user_max_freq_req: PM QoS maximum frequency request from user (via sysfs)
144 * @scaling_min_freq: Limit minimum frequency requested by OPP interface
145 * @scaling_max_freq: Limit maximum frequency requested by OPP interface
146 * @stop_polling: devfreq polling status of a device.
147 * @suspend_freq: frequency of a device set during suspend phase.
148 * @resume_freq: frequency of a device set in resume phase.
149 * @suspend_count: suspend requests counter for a device.
150 * @stats: Statistics of devfreq device behavior
151 * @transition_notifier_list: list head of DEVFREQ_TRANSITION_NOTIFIER notifier
152 * @nb_min: Notifier block for DEV_PM_QOS_MIN_FREQUENCY
153 * @nb_max: Notifier block for DEV_PM_QOS_MAX_FREQUENCY
155 * This structure stores the devfreq information for a given device.
157 * Note that when a governor accesses entries in struct devfreq in its
158 * functions except for the context of callbacks defined in struct
159 * devfreq_governor, the governor should protect its access with the
160 * struct mutex lock in struct devfreq. A governor may use this mutex
161 * to protect its own private data in void *data as well.
164 struct list_head node;
168 struct devfreq_dev_profile *profile;
169 const struct devfreq_governor *governor;
170 char governor_name[DEVFREQ_NAME_LEN];
171 struct notifier_block nb;
172 struct delayed_work work;
174 unsigned long previous_freq;
175 struct devfreq_dev_status last_status;
177 void *data; /* private data for governors */
179 struct dev_pm_qos_request user_min_freq_req;
180 struct dev_pm_qos_request user_max_freq_req;
181 unsigned long scaling_min_freq;
182 unsigned long scaling_max_freq;
185 unsigned long suspend_freq;
186 unsigned long resume_freq;
187 atomic_t suspend_count;
189 /* information for device frequency transitions */
190 struct devfreq_stats stats;
192 struct srcu_notifier_head transition_notifier_list;
194 struct notifier_block nb_min;
195 struct notifier_block nb_max;
198 struct devfreq_freqs {
203 #if defined(CONFIG_PM_DEVFREQ)
204 extern struct devfreq *devfreq_add_device(struct device *dev,
205 struct devfreq_dev_profile *profile,
206 const char *governor_name,
208 extern int devfreq_remove_device(struct devfreq *devfreq);
209 extern struct devfreq *devm_devfreq_add_device(struct device *dev,
210 struct devfreq_dev_profile *profile,
211 const char *governor_name,
213 extern void devm_devfreq_remove_device(struct device *dev,
214 struct devfreq *devfreq);
216 /* Supposed to be called by PM callbacks */
217 extern int devfreq_suspend_device(struct devfreq *devfreq);
218 extern int devfreq_resume_device(struct devfreq *devfreq);
220 extern void devfreq_suspend(void);
221 extern void devfreq_resume(void);
224 * update_devfreq() - Reevaluate the device and configure frequency
225 * @devfreq: the devfreq device
227 * Note: devfreq->lock must be held
229 extern int update_devfreq(struct devfreq *devfreq);
231 /* Helper functions for devfreq user device driver with OPP. */
232 extern struct dev_pm_opp *devfreq_recommended_opp(struct device *dev,
233 unsigned long *freq, u32 flags);
234 extern int devfreq_register_opp_notifier(struct device *dev,
235 struct devfreq *devfreq);
236 extern int devfreq_unregister_opp_notifier(struct device *dev,
237 struct devfreq *devfreq);
238 extern int devm_devfreq_register_opp_notifier(struct device *dev,
239 struct devfreq *devfreq);
240 extern void devm_devfreq_unregister_opp_notifier(struct device *dev,
241 struct devfreq *devfreq);
242 extern int devfreq_register_notifier(struct devfreq *devfreq,
243 struct notifier_block *nb,
245 extern int devfreq_unregister_notifier(struct devfreq *devfreq,
246 struct notifier_block *nb,
248 extern int devm_devfreq_register_notifier(struct device *dev,
249 struct devfreq *devfreq,
250 struct notifier_block *nb,
252 extern void devm_devfreq_unregister_notifier(struct device *dev,
253 struct devfreq *devfreq,
254 struct notifier_block *nb,
256 extern struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev,
259 #if IS_ENABLED(CONFIG_DEVFREQ_GOV_SIMPLE_ONDEMAND)
261 * struct devfreq_simple_ondemand_data - void *data fed to struct devfreq
262 * and devfreq_add_device
263 * @upthreshold: If the load is over this value, the frequency jumps.
264 * Specify 0 to use the default. Valid value = 0 to 100.
265 * @downdifferential: If the load is under upthreshold - downdifferential,
266 * the governor may consider slowing the frequency down.
267 * Specify 0 to use the default. Valid value = 0 to 100.
268 * downdifferential < upthreshold must hold.
270 * If the fed devfreq_simple_ondemand_data pointer is NULL to the governor,
271 * the governor uses the default values.
273 struct devfreq_simple_ondemand_data {
274 unsigned int upthreshold;
275 unsigned int downdifferential;
279 #if IS_ENABLED(CONFIG_DEVFREQ_GOV_PASSIVE)
281 * struct devfreq_passive_data - void *data fed to struct devfreq
282 * and devfreq_add_device
283 * @parent: the devfreq instance of parent device.
284 * @get_target_freq: Optional callback, Returns desired operating frequency
285 * for the device using passive governor. That is called
286 * when passive governor should decide the next frequency
287 * by using the new frequency of parent devfreq device
288 * using governors except for passive governor.
289 * If the devfreq device has the specific method to decide
290 * the next frequency, should use this callback.
291 * @this: the devfreq instance of own device.
292 * @nb: the notifier block for DEVFREQ_TRANSITION_NOTIFIER list
294 * The devfreq_passive_data have to set the devfreq instance of parent
295 * device with governors except for the passive governor. But, don't need to
296 * initialize the 'this' and 'nb' field because the devfreq core will handle
299 struct devfreq_passive_data {
300 /* Should set the devfreq instance of parent device */
301 struct devfreq *parent;
303 /* Optional callback to decide the next frequency of passvice device */
304 int (*get_target_freq)(struct devfreq *this, unsigned long *freq);
306 /* For passive governor's internal use. Don't need to set them */
307 struct devfreq *this;
308 struct notifier_block nb;
312 #else /* !CONFIG_PM_DEVFREQ */
313 static inline struct devfreq *devfreq_add_device(struct device *dev,
314 struct devfreq_dev_profile *profile,
315 const char *governor_name,
318 return ERR_PTR(-ENOSYS);
321 static inline int devfreq_remove_device(struct devfreq *devfreq)
326 static inline struct devfreq *devm_devfreq_add_device(struct device *dev,
327 struct devfreq_dev_profile *profile,
328 const char *governor_name,
331 return ERR_PTR(-ENOSYS);
334 static inline void devm_devfreq_remove_device(struct device *dev,
335 struct devfreq *devfreq)
339 static inline int devfreq_suspend_device(struct devfreq *devfreq)
344 static inline int devfreq_resume_device(struct devfreq *devfreq)
349 static inline void devfreq_suspend(void) {}
350 static inline void devfreq_resume(void) {}
352 static inline struct dev_pm_opp *devfreq_recommended_opp(struct device *dev,
353 unsigned long *freq, u32 flags)
355 return ERR_PTR(-EINVAL);
358 static inline int devfreq_register_opp_notifier(struct device *dev,
359 struct devfreq *devfreq)
364 static inline int devfreq_unregister_opp_notifier(struct device *dev,
365 struct devfreq *devfreq)
370 static inline int devm_devfreq_register_opp_notifier(struct device *dev,
371 struct devfreq *devfreq)
376 static inline void devm_devfreq_unregister_opp_notifier(struct device *dev,
377 struct devfreq *devfreq)
381 static inline int devfreq_register_notifier(struct devfreq *devfreq,
382 struct notifier_block *nb,
388 static inline int devfreq_unregister_notifier(struct devfreq *devfreq,
389 struct notifier_block *nb,
395 static inline int devm_devfreq_register_notifier(struct device *dev,
396 struct devfreq *devfreq,
397 struct notifier_block *nb,
403 static inline void devm_devfreq_unregister_notifier(struct device *dev,
404 struct devfreq *devfreq,
405 struct notifier_block *nb,
410 static inline struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev,
413 return ERR_PTR(-ENODEV);
416 static inline int devfreq_update_stats(struct devfreq *df)
420 #endif /* CONFIG_PM_DEVFREQ */
422 #endif /* __LINUX_DEVFREQ_H__ */