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 /* 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"
25 /* DEVFREQ notifier interface */
26 #define DEVFREQ_TRANSITION_NOTIFIER (0)
28 /* Transition notifiers of DEVFREQ_TRANSITION_NOTIFIER */
29 #define DEVFREQ_PRECHANGE (0)
30 #define DEVFREQ_POSTCHANGE (1)
32 /* DEVFREQ work timers */
34 DEVFREQ_TIMER_DEFERRABLE = 0,
35 DEVFREQ_TIMER_DELAYED,
40 struct devfreq_governor;
41 struct thermal_cooling_device;
44 * struct devfreq_dev_status - Data given from devfreq user device to
45 * governors. Represents the performance
47 * @total_time: The total time represented by this instance of
49 * @busy_time: The time that the device was working among the
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.
58 struct devfreq_dev_status {
59 /* both since the last measure */
60 unsigned long total_time;
61 unsigned long busy_time;
62 unsigned long current_frequency;
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)
72 #define DEVFREQ_FLAG_LEAST_UPPER_BOUND 0x1
75 * struct devfreq_dev_profile - Devfreq's user device profile
76 * @initial_freq: The operating frequency when devfreq_add_device() is
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.
103 * @is_cooling_device: A self-explanatory boolean giving the device a
104 * cooling effect property.
106 struct devfreq_dev_profile {
107 unsigned long initial_freq;
108 unsigned int polling_ms;
109 enum devfreq_timer timer;
110 bool is_cooling_device;
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);
118 unsigned long *freq_table;
119 unsigned int max_state;
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.
129 struct devfreq_stats {
130 unsigned int total_trans;
131 unsigned int *trans_table;
137 * struct devfreq - Device devfreq structure
138 * @node: list node - contains the devices with devfreq that have been
140 * @lock: a mutex to protect accessing devfreq.
141 * @dev: device registered by devfreq class. dev.parent is the device
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: devfreq driver pass to governors, governor should not change it.
153 * @governor_data: private data for governors, devfreq core doesn't touch it.
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
168 * This structure stores the devfreq information for a given device.
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.
177 struct list_head node;
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;
187 unsigned long previous_freq;
188 struct devfreq_dev_status last_status;
193 struct dev_pm_qos_request user_min_freq_req;
194 struct dev_pm_qos_request user_max_freq_req;
195 unsigned long scaling_min_freq;
196 unsigned long scaling_max_freq;
199 unsigned long suspend_freq;
200 unsigned long resume_freq;
201 atomic_t suspend_count;
203 /* information for device frequency transitions */
204 struct devfreq_stats stats;
206 struct srcu_notifier_head transition_notifier_list;
208 /* Pointer to the cooling device if used for thermal mitigation */
209 struct thermal_cooling_device *cdev;
211 struct notifier_block nb_min;
212 struct notifier_block nb_max;
215 struct devfreq_freqs {
220 #if defined(CONFIG_PM_DEVFREQ)
221 struct devfreq *devfreq_add_device(struct device *dev,
222 struct devfreq_dev_profile *profile,
223 const char *governor_name,
225 int devfreq_remove_device(struct devfreq *devfreq);
226 struct devfreq *devm_devfreq_add_device(struct device *dev,
227 struct devfreq_dev_profile *profile,
228 const char *governor_name,
230 void devm_devfreq_remove_device(struct device *dev, struct devfreq *devfreq);
232 /* Supposed to be called by PM callbacks */
233 int devfreq_suspend_device(struct devfreq *devfreq);
234 int devfreq_resume_device(struct devfreq *devfreq);
236 void devfreq_suspend(void);
237 void devfreq_resume(void);
239 /* update_devfreq() - Reevaluate the device and configure frequency */
240 int update_devfreq(struct devfreq *devfreq);
242 /* Helper functions for devfreq user device driver with OPP. */
243 struct dev_pm_opp *devfreq_recommended_opp(struct device *dev,
244 unsigned long *freq, u32 flags);
245 int devfreq_register_opp_notifier(struct device *dev,
246 struct devfreq *devfreq);
247 int devfreq_unregister_opp_notifier(struct device *dev,
248 struct devfreq *devfreq);
249 int devm_devfreq_register_opp_notifier(struct device *dev,
250 struct devfreq *devfreq);
251 void devm_devfreq_unregister_opp_notifier(struct device *dev,
252 struct devfreq *devfreq);
253 int devfreq_register_notifier(struct devfreq *devfreq,
254 struct notifier_block *nb,
256 int devfreq_unregister_notifier(struct devfreq *devfreq,
257 struct notifier_block *nb,
259 int devm_devfreq_register_notifier(struct device *dev,
260 struct devfreq *devfreq,
261 struct notifier_block *nb,
263 void devm_devfreq_unregister_notifier(struct device *dev,
264 struct devfreq *devfreq,
265 struct notifier_block *nb,
267 struct devfreq *devfreq_get_devfreq_by_node(struct device_node *node);
268 struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev,
269 const char *phandle_name, int index);
271 #if IS_ENABLED(CONFIG_DEVFREQ_GOV_SIMPLE_ONDEMAND)
273 * struct devfreq_simple_ondemand_data - ``void *data`` fed to struct devfreq
274 * and devfreq_add_device
275 * @upthreshold: If the load is over this value, the frequency jumps.
276 * Specify 0 to use the default. Valid value = 0 to 100.
277 * @downdifferential: If the load is under upthreshold - downdifferential,
278 * the governor may consider slowing the frequency down.
279 * Specify 0 to use the default. Valid value = 0 to 100.
280 * downdifferential < upthreshold must hold.
282 * If the fed devfreq_simple_ondemand_data pointer is NULL to the governor,
283 * the governor uses the default values.
285 struct devfreq_simple_ondemand_data {
286 unsigned int upthreshold;
287 unsigned int downdifferential;
291 #if IS_ENABLED(CONFIG_DEVFREQ_GOV_PASSIVE)
293 * struct devfreq_passive_data - ``void *data`` fed to struct devfreq
294 * and devfreq_add_device
295 * @parent: the devfreq instance of parent device.
296 * @get_target_freq: Optional callback, Returns desired operating frequency
297 * for the device using passive governor. That is called
298 * when passive governor should decide the next frequency
299 * by using the new frequency of parent devfreq device
300 * using governors except for passive governor.
301 * If the devfreq device has the specific method to decide
302 * the next frequency, should use this callback.
303 * @this: the devfreq instance of own device.
304 * @nb: the notifier block for DEVFREQ_TRANSITION_NOTIFIER list
306 * The devfreq_passive_data have to set the devfreq instance of parent
307 * device with governors except for the passive governor. But, don't need to
308 * initialize the 'this' and 'nb' field because the devfreq core will handle
311 struct devfreq_passive_data {
312 /* Should set the devfreq instance of parent device */
313 struct devfreq *parent;
315 /* Optional callback to decide the next frequency of passvice device */
316 int (*get_target_freq)(struct devfreq *this, unsigned long *freq);
318 /* For passive governor's internal use. Don't need to set them */
319 struct devfreq *this;
320 struct notifier_block nb;
324 #else /* !CONFIG_PM_DEVFREQ */
325 static inline struct devfreq *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 int devfreq_remove_device(struct devfreq *devfreq)
338 static inline struct devfreq *devm_devfreq_add_device(struct device *dev,
339 struct devfreq_dev_profile *profile,
340 const char *governor_name,
343 return ERR_PTR(-ENOSYS);
346 static inline void devm_devfreq_remove_device(struct device *dev,
347 struct devfreq *devfreq)
351 static inline int devfreq_suspend_device(struct devfreq *devfreq)
356 static inline int devfreq_resume_device(struct devfreq *devfreq)
361 static inline void devfreq_suspend(void) {}
362 static inline void devfreq_resume(void) {}
364 static inline struct dev_pm_opp *devfreq_recommended_opp(struct device *dev,
365 unsigned long *freq, u32 flags)
367 return ERR_PTR(-EINVAL);
370 static inline int devfreq_register_opp_notifier(struct device *dev,
371 struct devfreq *devfreq)
376 static inline int devfreq_unregister_opp_notifier(struct device *dev,
377 struct devfreq *devfreq)
382 static inline int devm_devfreq_register_opp_notifier(struct device *dev,
383 struct devfreq *devfreq)
388 static inline void devm_devfreq_unregister_opp_notifier(struct device *dev,
389 struct devfreq *devfreq)
393 static inline int devfreq_register_notifier(struct devfreq *devfreq,
394 struct notifier_block *nb,
400 static inline int devfreq_unregister_notifier(struct devfreq *devfreq,
401 struct notifier_block *nb,
407 static inline int devm_devfreq_register_notifier(struct device *dev,
408 struct devfreq *devfreq,
409 struct notifier_block *nb,
415 static inline void devm_devfreq_unregister_notifier(struct device *dev,
416 struct devfreq *devfreq,
417 struct notifier_block *nb,
422 static inline struct devfreq *devfreq_get_devfreq_by_node(struct device_node *node)
424 return ERR_PTR(-ENODEV);
427 static inline struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev,
428 const char *phandle_name, int index)
430 return ERR_PTR(-ENODEV);
433 static inline int devfreq_update_stats(struct devfreq *df)
437 #endif /* CONFIG_PM_DEVFREQ */
439 #endif /* __LINUX_DEVFREQ_H__ */