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>
17 #define DEVFREQ_NAME_LEN 16
19 /* DEVFREQ governor name */
20 #define DEVFREQ_GOV_SIMPLE_ONDEMAND "simple_ondemand"
21 #define DEVFREQ_GOV_PERFORMANCE "performance"
22 #define DEVFREQ_GOV_POWERSAVE "powersave"
23 #define DEVFREQ_GOV_USERSPACE "userspace"
24 #define DEVFREQ_GOV_PASSIVE "passive"
26 /* DEVFREQ notifier interface */
27 #define DEVFREQ_TRANSITION_NOTIFIER (0)
29 /* Transition notifiers of DEVFREQ_TRANSITION_NOTIFIER */
30 #define DEVFREQ_PRECHANGE (0)
31 #define DEVFREQ_POSTCHANGE (1)
34 struct devfreq_governor;
37 * struct devfreq_dev_status - Data given from devfreq user device to
38 * governors. Represents the performance
40 * @total_time: The total time represented by this instance of
42 * @busy_time: The time that the device was working among the
44 * @current_frequency: The operating frequency.
45 * @private_data: An entry not specified by the devfreq framework.
46 * A device and a specific governor may have their
47 * own protocol with private_data. However, because
48 * this is governor-specific, a governor using this
49 * will be only compatible with devices aware of it.
51 struct devfreq_dev_status {
52 /* both since the last measure */
53 unsigned long total_time;
54 unsigned long busy_time;
55 unsigned long current_frequency;
60 * The resulting frequency should be at most this. (this bound is the
61 * least upper bound; thus, the resulting freq should be lower or same)
62 * If the flag is not set, the resulting frequency should be at most the
63 * bound (greatest lower bound)
65 #define DEVFREQ_FLAG_LEAST_UPPER_BOUND 0x1
68 * struct devfreq_dev_profile - Devfreq's user device profile
69 * @initial_freq: The operating frequency when devfreq_add_device() is
71 * @polling_ms: The polling interval in ms. 0 disables polling.
72 * @target: The device should set its operating frequency at
73 * freq or lowest-upper-than-freq value. If freq is
74 * higher than any operable frequency, set maximum.
75 * Before returning, target function should set
76 * freq at the current frequency.
77 * The "flags" parameter's possible values are
78 * explained above with "DEVFREQ_FLAG_*" macros.
79 * @get_dev_status: The device should provide the current performance
80 * status to devfreq. Governors are recommended not to
81 * use this directly. Instead, governors are recommended
82 * to use devfreq_update_stats() along with
83 * devfreq.last_status.
84 * @get_cur_freq: The device should provide the current frequency
85 * at which it is operating.
86 * @exit: An optional callback that is called when devfreq
87 * is removing the devfreq object due to error or
88 * from devfreq_remove_device() call. If the user
89 * has registered devfreq->nb at a notifier-head,
90 * this is the time to unregister it.
91 * @freq_table: Optional list of frequencies to support statistics
92 * and freq_table must be generated in ascending order.
93 * @max_state: The size of freq_table.
95 struct devfreq_dev_profile {
96 unsigned long initial_freq;
97 unsigned int polling_ms;
99 int (*target)(struct device *dev, unsigned long *freq, u32 flags);
100 int (*get_dev_status)(struct device *dev,
101 struct devfreq_dev_status *stat);
102 int (*get_cur_freq)(struct device *dev, unsigned long *freq);
103 void (*exit)(struct device *dev);
105 unsigned long *freq_table;
106 unsigned int max_state;
110 * struct devfreq - Device devfreq structure
111 * @node: list node - contains the devices with devfreq that have been
113 * @lock: a mutex to protect accessing devfreq.
114 * @dev: device registered by devfreq class. dev.parent is the device
116 * @profile: device-specific devfreq profile
117 * @governor: method how to choose frequency based on the usage.
118 * @governor_name: devfreq governor name for use with this devfreq
119 * @nb: notifier block used to notify devfreq object that it should
120 * reevaluate operable frequencies. Devfreq users may use
121 * devfreq.nb to the corresponding register notifier call chain.
122 * @work: delayed work for load monitoring.
123 * @previous_freq: previously configured frequency value.
124 * @data: devfreq driver pass to governors, governor should not change it.
125 * @governor_data: private data for governors, devfreq core doesn't touch it.
126 * @min_freq: Limit minimum frequency requested by user (0: none)
127 * @max_freq: Limit maximum frequency requested by user (0: none)
128 * @scaling_min_freq: Limit minimum frequency requested by OPP interface
129 * @scaling_max_freq: Limit maximum frequency requested by OPP interface
130 * @stop_polling: devfreq polling status of a device.
131 * @suspend_freq: frequency of a device set during suspend phase.
132 * @resume_freq: frequency of a device set in resume phase.
133 * @suspend_count: suspend requests counter for 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
140 * This structure stores the devfreq information for a give device.
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.
149 struct list_head node;
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;
159 unsigned long previous_freq;
160 struct devfreq_dev_status last_status;
165 unsigned long min_freq;
166 unsigned long max_freq;
167 unsigned long scaling_min_freq;
168 unsigned long scaling_max_freq;
171 unsigned long suspend_freq;
172 unsigned long resume_freq;
173 atomic_t suspend_count;
175 /* information for device frequency transition */
176 unsigned int total_trans;
177 unsigned int *trans_table;
178 unsigned long *time_in_state;
179 unsigned long last_stat_updated;
181 struct srcu_notifier_head transition_notifier_list;
184 struct devfreq_freqs {
189 #if defined(CONFIG_PM_DEVFREQ)
190 extern struct devfreq *devfreq_add_device(struct device *dev,
191 struct devfreq_dev_profile *profile,
192 const char *governor_name,
194 extern int devfreq_remove_device(struct devfreq *devfreq);
195 extern struct devfreq *devm_devfreq_add_device(struct device *dev,
196 struct devfreq_dev_profile *profile,
197 const char *governor_name,
199 extern void devm_devfreq_remove_device(struct device *dev,
200 struct devfreq *devfreq);
202 /* Supposed to be called by PM callbacks */
203 extern int devfreq_suspend_device(struct devfreq *devfreq);
204 extern int devfreq_resume_device(struct devfreq *devfreq);
206 extern void devfreq_suspend(void);
207 extern void devfreq_resume(void);
210 * update_devfreq() - Reevaluate the device and configure frequency
211 * @devfreq: the devfreq device
213 * Note: devfreq->lock must be held
215 extern int update_devfreq(struct devfreq *devfreq);
217 /* Helper functions for devfreq user device driver with OPP. */
218 extern struct dev_pm_opp *devfreq_recommended_opp(struct device *dev,
219 unsigned long *freq, u32 flags);
220 extern int devfreq_register_opp_notifier(struct device *dev,
221 struct devfreq *devfreq);
222 extern int devfreq_unregister_opp_notifier(struct device *dev,
223 struct devfreq *devfreq);
224 extern int devm_devfreq_register_opp_notifier(struct device *dev,
225 struct devfreq *devfreq);
226 extern void devm_devfreq_unregister_opp_notifier(struct device *dev,
227 struct devfreq *devfreq);
228 extern int devfreq_register_notifier(struct devfreq *devfreq,
229 struct notifier_block *nb,
231 extern int devfreq_unregister_notifier(struct devfreq *devfreq,
232 struct notifier_block *nb,
234 extern int devm_devfreq_register_notifier(struct device *dev,
235 struct devfreq *devfreq,
236 struct notifier_block *nb,
238 extern void devm_devfreq_unregister_notifier(struct device *dev,
239 struct devfreq *devfreq,
240 struct notifier_block *nb,
242 extern struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev,
245 #if IS_ENABLED(CONFIG_DEVFREQ_GOV_SIMPLE_ONDEMAND)
247 * struct devfreq_simple_ondemand_data - void *data fed to struct devfreq
248 * and devfreq_add_device
249 * @upthreshold: If the load is over this value, the frequency jumps.
250 * Specify 0 to use the default. Valid value = 0 to 100.
251 * @downdifferential: If the load is under upthreshold - downdifferential,
252 * the governor may consider slowing the frequency down.
253 * Specify 0 to use the default. Valid value = 0 to 100.
254 * downdifferential < upthreshold must hold.
256 * If the fed devfreq_simple_ondemand_data pointer is NULL to the governor,
257 * the governor uses the default values.
259 struct devfreq_simple_ondemand_data {
260 unsigned int upthreshold;
261 unsigned int downdifferential;
265 #if IS_ENABLED(CONFIG_DEVFREQ_GOV_PASSIVE)
267 * struct devfreq_passive_data - void *data fed to struct devfreq
268 * and devfreq_add_device
269 * @parent: the devfreq instance of parent device.
270 * @get_target_freq: Optional callback, Returns desired operating frequency
271 * for the device using passive governor. That is called
272 * when passive governor should decide the next frequency
273 * by using the new frequency of parent devfreq device
274 * using governors except for passive governor.
275 * If the devfreq device has the specific method to decide
276 * the next frequency, should use this callback.
277 * @this: the devfreq instance of own device.
278 * @nb: the notifier block for DEVFREQ_TRANSITION_NOTIFIER list
280 * The devfreq_passive_data have to set the devfreq instance of parent
281 * device with governors except for the passive governor. But, don't need to
282 * initialize the 'this' and 'nb' field because the devfreq core will handle
285 struct devfreq_passive_data {
286 /* Should set the devfreq instance of parent device */
287 struct devfreq *parent;
289 /* Optional callback to decide the next frequency of passvice device */
290 int (*get_target_freq)(struct devfreq *this, unsigned long *freq);
292 /* For passive governor's internal use. Don't need to set them */
293 struct devfreq *this;
294 struct notifier_block nb;
298 #else /* !CONFIG_PM_DEVFREQ */
299 static inline struct devfreq *devfreq_add_device(struct device *dev,
300 struct devfreq_dev_profile *profile,
301 const char *governor_name,
304 return ERR_PTR(-ENOSYS);
307 static inline int devfreq_remove_device(struct devfreq *devfreq)
312 static inline struct devfreq *devm_devfreq_add_device(struct device *dev,
313 struct devfreq_dev_profile *profile,
314 const char *governor_name,
317 return ERR_PTR(-ENOSYS);
320 static inline void devm_devfreq_remove_device(struct device *dev,
321 struct devfreq *devfreq)
325 static inline int devfreq_suspend_device(struct devfreq *devfreq)
330 static inline int devfreq_resume_device(struct devfreq *devfreq)
335 static inline void devfreq_suspend(void) {}
336 static inline void devfreq_resume(void) {}
338 static inline struct dev_pm_opp *devfreq_recommended_opp(struct device *dev,
339 unsigned long *freq, u32 flags)
341 return ERR_PTR(-EINVAL);
344 static inline int devfreq_register_opp_notifier(struct device *dev,
345 struct devfreq *devfreq)
350 static inline int devfreq_unregister_opp_notifier(struct device *dev,
351 struct devfreq *devfreq)
356 static inline int devm_devfreq_register_opp_notifier(struct device *dev,
357 struct devfreq *devfreq)
362 static inline void devm_devfreq_unregister_opp_notifier(struct device *dev,
363 struct devfreq *devfreq)
367 static inline int devfreq_register_notifier(struct devfreq *devfreq,
368 struct notifier_block *nb,
374 static inline int devfreq_unregister_notifier(struct devfreq *devfreq,
375 struct notifier_block *nb,
381 static inline int devm_devfreq_register_notifier(struct device *dev,
382 struct devfreq *devfreq,
383 struct notifier_block *nb,
389 static inline void devm_devfreq_unregister_notifier(struct device *dev,
390 struct devfreq *devfreq,
391 struct notifier_block *nb,
396 static inline struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev,
399 return ERR_PTR(-ENODEV);
402 static inline int devfreq_update_stats(struct devfreq *df)
406 #endif /* CONFIG_PM_DEVFREQ */
408 #endif /* __LINUX_DEVFREQ_H__ */