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 devfreq_cpu_data;
42 struct thermal_cooling_device;
45 * struct devfreq_dev_status - Data given from devfreq user device to
46 * governors. Represents the performance
48 * @total_time: The total time represented by this instance of
50 * @busy_time: The time that the device was working among the
52 * @current_frequency: The operating frequency.
53 * @private_data: An entry not specified by the devfreq framework.
54 * A device and a specific governor may have their
55 * own protocol with private_data. However, because
56 * this is governor-specific, a governor using this
57 * will be only compatible with devices aware of it.
59 struct devfreq_dev_status {
60 /* both since the last measure */
61 unsigned long total_time;
62 unsigned long busy_time;
63 unsigned long current_frequency;
68 * The resulting frequency should be at most this. (this bound is the
69 * least upper bound; thus, the resulting freq should be lower or same)
70 * If the flag is not set, the resulting frequency should be at most the
71 * bound (greatest lower bound)
73 #define DEVFREQ_FLAG_LEAST_UPPER_BOUND 0x1
76 * struct devfreq_dev_profile - Devfreq's user device profile
77 * @initial_freq: The operating frequency when devfreq_add_device() is
79 * @polling_ms: The polling interval in ms. 0 disables polling.
80 * @timer: Timer type is either deferrable or delayed timer.
81 * @target: The device should set its operating frequency at
82 * freq or lowest-upper-than-freq value. If freq is
83 * higher than any operable frequency, set maximum.
84 * Before returning, target function should set
85 * freq at the current frequency.
86 * The "flags" parameter's possible values are
87 * explained above with "DEVFREQ_FLAG_*" macros.
88 * @get_dev_status: The device should provide the current performance
89 * status to devfreq. Governors are recommended not to
90 * use this directly. Instead, governors are recommended
91 * to use devfreq_update_stats() along with
92 * devfreq.last_status.
93 * @get_cur_freq: The device should provide the current frequency
94 * at which it is operating.
95 * @exit: An optional callback that is called when devfreq
96 * is removing the devfreq object due to error or
97 * from devfreq_remove_device() call. If the user
98 * has registered devfreq->nb at a notifier-head,
99 * this is the time to unregister it.
100 * @freq_table: Optional list of frequencies to support statistics
101 * and freq_table must be generated in ascending order.
102 * @max_state: The size of freq_table.
104 * @is_cooling_device: A self-explanatory boolean giving the device a
105 * cooling effect property.
107 struct devfreq_dev_profile {
108 unsigned long initial_freq;
109 unsigned int polling_ms;
110 enum devfreq_timer timer;
111 bool is_cooling_device;
113 int (*target)(struct device *dev, unsigned long *freq, u32 flags);
114 int (*get_dev_status)(struct device *dev,
115 struct devfreq_dev_status *stat);
116 int (*get_cur_freq)(struct device *dev, unsigned long *freq);
117 void (*exit)(struct device *dev);
119 unsigned long *freq_table;
120 unsigned int max_state;
124 * struct devfreq_stats - Statistics of devfreq device behavior
125 * @total_trans: Number of devfreq transitions.
126 * @trans_table: Statistics of devfreq transitions.
127 * @time_in_state: Statistics of devfreq states.
128 * @last_update: The last time stats were updated.
130 struct devfreq_stats {
131 unsigned int total_trans;
132 unsigned int *trans_table;
138 * struct devfreq - Device devfreq structure
139 * @node: list node - contains the devices with devfreq that have been
141 * @lock: a mutex to protect accessing devfreq.
142 * @dev: device registered by devfreq class. dev.parent is the device
144 * @profile: device-specific devfreq profile
145 * @governor: method how to choose frequency based on the usage.
146 * @opp_table: Reference to OPP table of dev.parent, if one exists.
147 * @nb: notifier block used to notify devfreq object that it should
148 * reevaluate operable frequencies. Devfreq users may use
149 * devfreq.nb to the corresponding register notifier call chain.
150 * @work: delayed work for load monitoring.
151 * @previous_freq: previously configured frequency value.
152 * @last_status: devfreq user device info, performance statistics
153 * @data: Private data of the governor. The devfreq framework does not
155 * @user_min_freq_req: PM QoS minimum frequency request from user (via sysfs)
156 * @user_max_freq_req: PM QoS maximum frequency request from user (via sysfs)
157 * @scaling_min_freq: Limit minimum frequency requested by OPP interface
158 * @scaling_max_freq: Limit maximum frequency requested by OPP interface
159 * @stop_polling: devfreq polling status of a device.
160 * @suspend_freq: frequency of a device set during suspend phase.
161 * @resume_freq: frequency of a device set in resume phase.
162 * @suspend_count: suspend requests counter for a device.
163 * @stats: Statistics of devfreq device behavior
164 * @transition_notifier_list: list head of DEVFREQ_TRANSITION_NOTIFIER notifier
165 * @cdev: Cooling device pointer if the devfreq has cooling property
166 * @nb_min: Notifier block for DEV_PM_QOS_MIN_FREQUENCY
167 * @nb_max: Notifier block for DEV_PM_QOS_MAX_FREQUENCY
169 * This structure stores the devfreq information for a given device.
171 * Note that when a governor accesses entries in struct devfreq in its
172 * functions except for the context of callbacks defined in struct
173 * devfreq_governor, the governor should protect its access with the
174 * struct mutex lock in struct devfreq. A governor may use this mutex
175 * to protect its own private data in ``void *data`` as well.
178 struct list_head node;
182 struct devfreq_dev_profile *profile;
183 const struct devfreq_governor *governor;
184 struct opp_table *opp_table;
185 struct notifier_block nb;
186 struct delayed_work work;
188 unsigned long previous_freq;
189 struct devfreq_dev_status last_status;
191 void *data; /* private data for governors */
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)
292 enum devfreq_parent_dev_type {
298 * struct devfreq_passive_data - ``void *data`` fed to struct devfreq
299 * and devfreq_add_device
300 * @parent: the devfreq instance of parent device.
301 * @get_target_freq: Optional callback, Returns desired operating frequency
302 * for the device using passive governor. That is called
303 * when passive governor should decide the next frequency
304 * by using the new frequency of parent devfreq device
305 * using governors except for passive governor.
306 * If the devfreq device has the specific method to decide
307 * the next frequency, should use this callback.
308 * @parent_type: the parent type of the device.
309 * @this: the devfreq instance of own device.
310 * @nb: the notifier block for DEVFREQ_TRANSITION_NOTIFIER or
311 * CPUFREQ_TRANSITION_NOTIFIER list.
312 * @cpu_data_list: the list of cpu frequency data for all cpufreq_policy.
314 * The devfreq_passive_data have to set the devfreq instance of parent
315 * device with governors except for the passive governor. But, don't need to
316 * initialize the 'this' and 'nb' field because the devfreq core will handle
319 struct devfreq_passive_data {
320 /* Should set the devfreq instance of parent device */
321 struct devfreq *parent;
323 /* Optional callback to decide the next frequency of passvice device */
324 int (*get_target_freq)(struct devfreq *this, unsigned long *freq);
326 /* Should set the type of parent device */
327 enum devfreq_parent_dev_type parent_type;
329 /* For passive governor's internal use. Don't need to set them */
330 struct devfreq *this;
331 struct notifier_block nb;
332 struct list_head cpu_data_list;
336 #else /* !CONFIG_PM_DEVFREQ */
337 static inline struct devfreq *devfreq_add_device(struct device *dev,
338 struct devfreq_dev_profile *profile,
339 const char *governor_name,
342 return ERR_PTR(-ENOSYS);
345 static inline int devfreq_remove_device(struct devfreq *devfreq)
350 static inline struct devfreq *devm_devfreq_add_device(struct device *dev,
351 struct devfreq_dev_profile *profile,
352 const char *governor_name,
355 return ERR_PTR(-ENOSYS);
358 static inline void devm_devfreq_remove_device(struct device *dev,
359 struct devfreq *devfreq)
363 static inline int devfreq_suspend_device(struct devfreq *devfreq)
368 static inline int devfreq_resume_device(struct devfreq *devfreq)
373 static inline void devfreq_suspend(void) {}
374 static inline void devfreq_resume(void) {}
376 static inline struct dev_pm_opp *devfreq_recommended_opp(struct device *dev,
377 unsigned long *freq, u32 flags)
379 return ERR_PTR(-EINVAL);
382 static inline int devfreq_register_opp_notifier(struct device *dev,
383 struct devfreq *devfreq)
388 static inline int devfreq_unregister_opp_notifier(struct device *dev,
389 struct devfreq *devfreq)
394 static inline int devm_devfreq_register_opp_notifier(struct device *dev,
395 struct devfreq *devfreq)
400 static inline void devm_devfreq_unregister_opp_notifier(struct device *dev,
401 struct devfreq *devfreq)
405 static inline int devfreq_register_notifier(struct devfreq *devfreq,
406 struct notifier_block *nb,
412 static inline int devfreq_unregister_notifier(struct devfreq *devfreq,
413 struct notifier_block *nb,
419 static inline int devm_devfreq_register_notifier(struct device *dev,
420 struct devfreq *devfreq,
421 struct notifier_block *nb,
427 static inline void devm_devfreq_unregister_notifier(struct device *dev,
428 struct devfreq *devfreq,
429 struct notifier_block *nb,
434 static inline struct devfreq *devfreq_get_devfreq_by_node(struct device_node *node)
436 return ERR_PTR(-ENODEV);
439 static inline struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev,
440 const char *phandle_name, int index)
442 return ERR_PTR(-ENODEV);
445 static inline int devfreq_update_stats(struct devfreq *df)
449 #endif /* CONFIG_PM_DEVFREQ */
451 #endif /* __LINUX_DEVFREQ_H__ */