2 * devfreq: Generic Dynamic Voltage and Frequency Scaling (DVFS) Framework
5 * Copyright (C) 2011 Samsung Electronics
6 * MyungJoo Ham <myungjoo.ham@samsung.com>
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2 as
10 * published by the Free Software Foundation.
13 #ifndef __LINUX_DEVFREQ_H__
14 #define __LINUX_DEVFREQ_H__
16 #include <linux/device.h>
17 #include <linux/notifier.h>
18 #include <linux/pm_opp.h>
20 #define DEVFREQ_NAME_LEN 16
22 /* DEVFREQ notifier interface */
23 #define DEVFREQ_TRANSITION_NOTIFIER (0)
25 /* Transition notifiers of DEVFREQ_TRANSITION_NOTIFIER */
26 #define DEVFREQ_PRECHANGE (0)
27 #define DEVFREQ_POSTCHANGE (1)
32 * struct devfreq_dev_status - Data given from devfreq user device to
33 * governors. Represents the performance
35 * @total_time: The total time represented by this instance of
37 * @busy_time: The time that the device was working among the
39 * @current_frequency: The operating frequency.
40 * @private_data: An entry not specified by the devfreq framework.
41 * A device and a specific governor may have their
42 * own protocol with private_data. However, because
43 * this is governor-specific, a governor using this
44 * will be only compatible with devices aware of it.
46 struct devfreq_dev_status
{
47 /* both since the last measure */
48 unsigned long total_time
;
49 unsigned long busy_time
;
50 unsigned long current_frequency
;
55 * The resulting frequency should be at most this. (this bound is the
56 * least upper bound; thus, the resulting freq should be lower or same)
57 * If the flag is not set, the resulting frequency should be at most the
58 * bound (greatest lower bound)
60 #define DEVFREQ_FLAG_LEAST_UPPER_BOUND 0x1
63 * struct devfreq_dev_profile - Devfreq's user device profile
64 * @initial_freq: The operating frequency when devfreq_add_device() is
66 * @polling_ms: The polling interval in ms. 0 disables polling.
67 * @target: The device should set its operating frequency at
68 * freq or lowest-upper-than-freq value. If freq is
69 * higher than any operable frequency, set maximum.
70 * Before returning, target function should set
71 * freq at the current frequency.
72 * The "flags" parameter's possible values are
73 * explained above with "DEVFREQ_FLAG_*" macros.
74 * @get_dev_status: The device should provide the current performance
75 * status to devfreq. Governors are recommended not to
76 * use this directly. Instead, governors are recommended
77 * to use devfreq_update_stats() along with
78 * devfreq.last_status.
79 * @get_cur_freq: The device should provide the current frequency
80 * at which it is operating.
81 * @exit: An optional callback that is called when devfreq
82 * is removing the devfreq object due to error or
83 * from devfreq_remove_device() call. If the user
84 * has registered devfreq->nb at a notifier-head,
85 * this is the time to unregister it.
86 * @freq_table: Optional list of frequencies to support statistics.
87 * @max_state: The size of freq_table.
89 struct devfreq_dev_profile
{
90 unsigned long initial_freq
;
91 unsigned int polling_ms
;
93 int (*target
)(struct device
*dev
, unsigned long *freq
, u32 flags
);
94 int (*get_dev_status
)(struct device
*dev
,
95 struct devfreq_dev_status
*stat
);
96 int (*get_cur_freq
)(struct device
*dev
, unsigned long *freq
);
97 void (*exit
)(struct device
*dev
);
99 unsigned long *freq_table
;
100 unsigned int max_state
;
104 * struct devfreq_governor - Devfreq policy governor
105 * @node: list node - contains registered devfreq governors
106 * @name: Governor's name
107 * @immutable: Immutable flag for governor. If the value is 1,
108 * this govenror is never changeable to other governor.
109 * @get_target_freq: Returns desired operating frequency for the device.
110 * Basically, get_target_freq will run
111 * devfreq_dev_profile.get_dev_status() to get the
112 * status of the device (load = busy_time / total_time).
113 * If no_central_polling is set, this callback is called
114 * only with update_devfreq() notified by OPP.
115 * @event_handler: Callback for devfreq core framework to notify events
116 * to governors. Events include per device governor
117 * init and exit, opp changes out of devfreq, suspend
118 * and resume of per device devfreq during device idle.
120 * Note that the callbacks are called with devfreq->lock locked by devfreq.
122 struct devfreq_governor
{
123 struct list_head node
;
125 const char name
[DEVFREQ_NAME_LEN
];
126 const unsigned int immutable
;
127 int (*get_target_freq
)(struct devfreq
*this, unsigned long *freq
);
128 int (*event_handler
)(struct devfreq
*devfreq
,
129 unsigned int event
, void *data
);
133 * struct devfreq - Device devfreq structure
134 * @node: list node - contains the devices with devfreq that have been
136 * @lock: a mutex to protect accessing devfreq.
137 * @dev: device registered by devfreq class. dev.parent is the device
139 * @profile: device-specific devfreq profile
140 * @governor: method how to choose frequency based on the usage.
141 * @governor_name: devfreq governor name for use with this devfreq
142 * @nb: notifier block used to notify devfreq object that it should
143 * reevaluate operable frequencies. Devfreq users may use
144 * devfreq.nb to the corresponding register notifier call chain.
145 * @work: delayed work for load monitoring.
146 * @previous_freq: previously configured frequency value.
147 * @data: Private data of the governor. The devfreq framework does not
149 * @min_freq: Limit minimum frequency requested by user (0: none)
150 * @max_freq: Limit maximum frequency requested by user (0: none)
151 * @stop_polling: devfreq polling status of a device.
152 * @total_trans: Number of devfreq transitions
153 * @trans_table: Statistics of devfreq transitions
154 * @time_in_state: Statistics of devfreq states
155 * @last_stat_updated: The last time stat updated
156 * @transition_notifier_list: list head of DEVFREQ_TRANSITION_NOTIFIER notifier
158 * This structure stores the devfreq information for a give device.
160 * Note that when a governor accesses entries in struct devfreq in its
161 * functions except for the context of callbacks defined in struct
162 * devfreq_governor, the governor should protect its access with the
163 * struct mutex lock in struct devfreq. A governor may use this mutex
164 * to protect its own private data in void *data as well.
167 struct list_head node
;
171 struct devfreq_dev_profile
*profile
;
172 const struct devfreq_governor
*governor
;
173 char governor_name
[DEVFREQ_NAME_LEN
];
174 struct notifier_block nb
;
175 struct delayed_work work
;
177 unsigned long previous_freq
;
178 struct devfreq_dev_status last_status
;
180 void *data
; /* private data for governors */
182 unsigned long min_freq
;
183 unsigned long max_freq
;
186 /* information for device frequency transition */
187 unsigned int total_trans
;
188 unsigned int *trans_table
;
189 unsigned long *time_in_state
;
190 unsigned long last_stat_updated
;
192 struct srcu_notifier_head transition_notifier_list
;
195 struct devfreq_freqs
{
200 #if defined(CONFIG_PM_DEVFREQ)
201 extern struct devfreq
*devfreq_add_device(struct device
*dev
,
202 struct devfreq_dev_profile
*profile
,
203 const char *governor_name
,
205 extern int devfreq_remove_device(struct devfreq
*devfreq
);
206 extern struct devfreq
*devm_devfreq_add_device(struct device
*dev
,
207 struct devfreq_dev_profile
*profile
,
208 const char *governor_name
,
210 extern void devm_devfreq_remove_device(struct device
*dev
,
211 struct devfreq
*devfreq
);
213 /* Supposed to be called by PM callbacks */
214 extern int devfreq_suspend_device(struct devfreq
*devfreq
);
215 extern int devfreq_resume_device(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
,
246 * devfreq_update_stats() - update the last_status pointer in struct devfreq
247 * @df: the devfreq instance whose status needs updating
249 * Governors are recommended to use this function along with last_status,
250 * which allows other entities to reuse the last_status without affecting
251 * the values fetched later by governors.
253 static inline int devfreq_update_stats(struct devfreq
*df
)
255 return df
->profile
->get_dev_status(df
->dev
.parent
, &df
->last_status
);
258 #if IS_ENABLED(CONFIG_DEVFREQ_GOV_SIMPLE_ONDEMAND)
260 * struct devfreq_simple_ondemand_data - void *data fed to struct devfreq
261 * and devfreq_add_device
262 * @upthreshold: If the load is over this value, the frequency jumps.
263 * Specify 0 to use the default. Valid value = 0 to 100.
264 * @downdifferential: If the load is under upthreshold - downdifferential,
265 * the governor may consider slowing the frequency down.
266 * Specify 0 to use the default. Valid value = 0 to 100.
267 * downdifferential < upthreshold must hold.
269 * If the fed devfreq_simple_ondemand_data pointer is NULL to the governor,
270 * the governor uses the default values.
272 struct devfreq_simple_ondemand_data
{
273 unsigned int upthreshold
;
274 unsigned int downdifferential
;
278 #if IS_ENABLED(CONFIG_DEVFREQ_GOV_PASSIVE)
280 * struct devfreq_passive_data - void *data fed to struct devfreq
281 * and devfreq_add_device
282 * @parent: the devfreq instance of parent device.
283 * @get_target_freq: Optional callback, Returns desired operating frequency
284 * for the device using passive governor. That is called
285 * when passive governor should decide the next frequency
286 * by using the new frequency of parent devfreq device
287 * using governors except for passive governor.
288 * If the devfreq device has the specific method to decide
289 * the next frequency, should use this callback.
290 * @this: the devfreq instance of own device.
291 * @nb: the notifier block for DEVFREQ_TRANSITION_NOTIFIER list
293 * The devfreq_passive_data have to set the devfreq instance of parent
294 * device with governors except for the passive governor. But, don't need to
295 * initialize the 'this' and 'nb' field because the devfreq core will handle
298 struct devfreq_passive_data
{
299 /* Should set the devfreq instance of parent device */
300 struct devfreq
*parent
;
302 /* Optional callback to decide the next frequency of passvice device */
303 int (*get_target_freq
)(struct devfreq
*this, unsigned long *freq
);
305 /* For passive governor's internal use. Don't need to set them */
306 struct devfreq
*this;
307 struct notifier_block nb
;
311 #else /* !CONFIG_PM_DEVFREQ */
312 static inline struct devfreq
*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 int devfreq_remove_device(struct devfreq
*devfreq
)
325 static inline struct devfreq
*devm_devfreq_add_device(struct device
*dev
,
326 struct devfreq_dev_profile
*profile
,
327 const char *governor_name
,
330 return ERR_PTR(-ENOSYS
);
333 static inline void devm_devfreq_remove_device(struct device
*dev
,
334 struct devfreq
*devfreq
)
338 static inline int devfreq_suspend_device(struct devfreq
*devfreq
)
343 static inline int devfreq_resume_device(struct devfreq
*devfreq
)
348 static inline struct dev_pm_opp
*devfreq_recommended_opp(struct device
*dev
,
349 unsigned long *freq
, u32 flags
)
351 return ERR_PTR(-EINVAL
);
354 static inline int devfreq_register_opp_notifier(struct device
*dev
,
355 struct devfreq
*devfreq
)
360 static inline int devfreq_unregister_opp_notifier(struct device
*dev
,
361 struct devfreq
*devfreq
)
366 static inline int devm_devfreq_register_opp_notifier(struct device
*dev
,
367 struct devfreq
*devfreq
)
372 static inline void devm_devfreq_unregister_opp_notifier(struct device
*dev
,
373 struct devfreq
*devfreq
)
377 static inline int devfreq_register_notifier(struct devfreq
*devfreq
,
378 struct notifier_block
*nb
,
384 static inline int devfreq_unregister_notifier(struct devfreq
*devfreq
,
385 struct notifier_block
*nb
,
391 static inline int devm_devfreq_register_notifier(struct device
*dev
,
392 struct devfreq
*devfreq
,
393 struct notifier_block
*nb
,
399 static inline void devm_devfreq_unregister_notifier(struct device
*dev
,
400 struct devfreq
*devfreq
,
401 struct notifier_block
*nb
,
406 static inline struct devfreq
*devfreq_get_devfreq_by_phandle(struct device
*dev
,
409 return ERR_PTR(-ENODEV
);
412 static inline int devfreq_update_stats(struct devfreq
*df
)
416 #endif /* CONFIG_PM_DEVFREQ */
418 #endif /* __LINUX_DEVFREQ_H__ */