devfreq.h

  1/* SPDX-License-Identifier: GPL-2.0-only */
  2/*
  3 * devfreq: Generic Dynamic Voltage and Frequency Scaling (DVFS) Framework
  4 *	    for Non-CPU Devices.
  5 *
  6 * Copyright (C) 2011 Samsung Electronics
  7 *	MyungJoo Ham <myungjoo.ham@samsung.com>
  8 */
  9
 10#ifndef __LINUX_DEVFREQ_H__
 11#define __LINUX_DEVFREQ_H__
 12
 13#include <linux/device.h>
 14#include <linux/notifier.h>
 15#include <linux/pm_opp.h>
 16#include <linux/pm_qos.h>
 17
 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"
 24
 25/* DEVFREQ notifier interface */
 26#define DEVFREQ_TRANSITION_NOTIFIER	(0)
 27
 28/* Transition notifiers of DEVFREQ_TRANSITION_NOTIFIER */
 29#define	DEVFREQ_PRECHANGE		(0)
 30#define DEVFREQ_POSTCHANGE		(1)
 31
 32/* DEVFREQ work timers */
 33enum devfreq_timer {
 34	DEVFREQ_TIMER_DEFERRABLE = 0,
 35	DEVFREQ_TIMER_DELAYED,
 36	DEVFREQ_TIMER_NUM,
 37};
 38
 39struct devfreq;
 40struct devfreq_governor;
 41struct devfreq_cpu_data;
 42struct thermal_cooling_device;
 43
 44/**
 45 * struct devfreq_dev_status - Data given from devfreq user device to
 46 *			     governors. Represents the performance
 47 *			     statistics.
 48 * @total_time:		The total time represented by this instance of
 49 *			devfreq_dev_status
 50 * @busy_time:		The time that the device was working among the
 51 *			total_time.
 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.
 58 */
 59struct devfreq_dev_status {
 60	/* both since the last measure */
 61	unsigned long total_time;
 62	unsigned long busy_time;
 63	unsigned long current_frequency;
 64	void *private_data;
 65};
 66
 67/*
 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)
 72 */
 73#define DEVFREQ_FLAG_LEAST_UPPER_BOUND		0x1
 74
 75/**
 76 * struct devfreq_dev_profile - Devfreq's user device profile
 77 * @initial_freq:	The operating frequency when devfreq_add_device() is
 78 *			called.
 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.
103 *
104 * @is_cooling_device: A self-explanatory boolean giving the device a
105 *                     cooling effect property.
106 * @dev_groups:		Optional device-specific sysfs attribute groups that to
107 *			be attached to the devfreq device.
108 */
109struct devfreq_dev_profile {
110	unsigned long initial_freq;
111	unsigned int polling_ms;
112	enum devfreq_timer timer;
113
114	int (*target)(struct device *dev, unsigned long *freq, u32 flags);
115	int (*get_dev_status)(struct device *dev,
116			      struct devfreq_dev_status *stat);
117	int (*get_cur_freq)(struct device *dev, unsigned long *freq);
118	void (*exit)(struct device *dev);
119
120	unsigned long *freq_table;
121	unsigned int max_state;
122
123	bool is_cooling_device;
124
125	const struct attribute_group **dev_groups;
126};
127
128/**
129 * struct devfreq_stats - Statistics of devfreq device behavior
130 * @total_trans:	Number of devfreq transitions.
131 * @trans_table:	Statistics of devfreq transitions.
132 * @time_in_state:	Statistics of devfreq states.
133 * @last_update:	The last time stats were updated.
134 */
135struct devfreq_stats {
136	unsigned int total_trans;
137	unsigned int *trans_table;
138	u64 *time_in_state;
139	u64 last_update;
140};
141
142/**
143 * struct devfreq - Device devfreq structure
144 * @node:	list node - contains the devices with devfreq that have been
145 *		registered.
146 * @lock:	a mutex to protect accessing devfreq.
147 * @dev:	device registered by devfreq class. dev.parent is the device
148 *		using devfreq.
149 * @profile:	device-specific devfreq profile
150 * @governor:	method how to choose frequency based on the usage.
151 * @opp_table:	Reference to OPP table of dev.parent, if one exists.
152 * @nb:		notifier block used to notify devfreq object that it should
153 *		reevaluate operable frequencies. Devfreq users may use
154 *		devfreq.nb to the corresponding register notifier call chain.
155 * @work:	delayed work for load monitoring.
156 * @freq_table:		current frequency table used by the devfreq driver.
157 * @max_state:		count of entry present in the frequency table.
158 * @previous_freq:	previously configured frequency value.
159 * @last_status:	devfreq user device info, performance statistics
160 * @data:	devfreq driver pass to governors, governor should not change it.
161 * @governor_data:	private data for governors, devfreq core doesn't touch it.
162 * @user_min_freq_req:	PM QoS minimum frequency request from user (via sysfs)
163 * @user_max_freq_req:	PM QoS maximum frequency request from user (via sysfs)
164 * @scaling_min_freq:	Limit minimum frequency requested by OPP interface
165 * @scaling_max_freq:	Limit maximum frequency requested by OPP interface
166 * @stop_polling:	 devfreq polling status of a device.
167 * @suspend_freq:	 frequency of a device set during suspend phase.
168 * @resume_freq:	 frequency of a device set in resume phase.
169 * @suspend_count:	 suspend requests counter for a device.
170 * @stats:	Statistics of devfreq device behavior
171 * @transition_notifier_list: list head of DEVFREQ_TRANSITION_NOTIFIER notifier
172 * @cdev:	Cooling device pointer if the devfreq has cooling property
173 * @nb_min:		Notifier block for DEV_PM_QOS_MIN_FREQUENCY
174 * @nb_max:		Notifier block for DEV_PM_QOS_MAX_FREQUENCY
175 *
176 * This structure stores the devfreq information for a given device.
177 *
178 * Note that when a governor accesses entries in struct devfreq in its
179 * functions except for the context of callbacks defined in struct
180 * devfreq_governor, the governor should protect its access with the
181 * struct mutex lock in struct devfreq. A governor may use this mutex
182 * to protect its own private data in ``void *data`` as well.
183 */
184struct devfreq {
185	struct list_head node;
186
187	struct mutex lock;
188	struct device dev;
189	struct devfreq_dev_profile *profile;
190	const struct devfreq_governor *governor;
191	struct opp_table *opp_table;
192	struct notifier_block nb;
193	struct delayed_work work;
194
195	unsigned long *freq_table;
196	unsigned int max_state;
197
198	unsigned long previous_freq;
199	struct devfreq_dev_status last_status;
200
201	void *data;
202	void *governor_data;
203
204	struct dev_pm_qos_request user_min_freq_req;
205	struct dev_pm_qos_request user_max_freq_req;
206	unsigned long scaling_min_freq;
207	unsigned long scaling_max_freq;
208	bool stop_polling;
209
210	unsigned long suspend_freq;
211	unsigned long resume_freq;
212	atomic_t suspend_count;
213
214	/* information for device frequency transitions */
215	struct devfreq_stats stats;
216
217	struct srcu_notifier_head transition_notifier_list;
218
219	/* Pointer to the cooling device if used for thermal mitigation */
220	struct thermal_cooling_device *cdev;
221
222	struct notifier_block nb_min;
223	struct notifier_block nb_max;
224};
225
226struct devfreq_freqs {
227	unsigned long old;
228	unsigned long new;
229};
230
231#if defined(CONFIG_PM_DEVFREQ)
232struct devfreq *devfreq_add_device(struct device *dev,
233				struct devfreq_dev_profile *profile,
234				const char *governor_name,
235				void *data);
236int devfreq_remove_device(struct devfreq *devfreq);
237struct devfreq *devm_devfreq_add_device(struct device *dev,
238				struct devfreq_dev_profile *profile,
239				const char *governor_name,
240				void *data);
241void devm_devfreq_remove_device(struct device *dev, struct devfreq *devfreq);
242
243/* Supposed to be called by PM callbacks */
244int devfreq_suspend_device(struct devfreq *devfreq);
245int devfreq_resume_device(struct devfreq *devfreq);
246
247void devfreq_suspend(void);
248void devfreq_resume(void);
249
250/* update_devfreq() - Reevaluate the device and configure frequency */
251int update_devfreq(struct devfreq *devfreq);
252
253/* Helper functions for devfreq user device driver with OPP. */
254struct dev_pm_opp *devfreq_recommended_opp(struct device *dev,
255				unsigned long *freq, u32 flags);
256int devfreq_register_opp_notifier(struct device *dev,
257				struct devfreq *devfreq);
258int devfreq_unregister_opp_notifier(struct device *dev,
259				struct devfreq *devfreq);
260int devm_devfreq_register_opp_notifier(struct device *dev,
261				struct devfreq *devfreq);
262void devm_devfreq_unregister_opp_notifier(struct device *dev,
263				struct devfreq *devfreq);
264int devfreq_register_notifier(struct devfreq *devfreq,
265				struct notifier_block *nb,
266				unsigned int list);
267int devfreq_unregister_notifier(struct devfreq *devfreq,
268				struct notifier_block *nb,
269				unsigned int list);
270int devm_devfreq_register_notifier(struct device *dev,
271				struct devfreq *devfreq,
272				struct notifier_block *nb,
273				unsigned int list);
274void devm_devfreq_unregister_notifier(struct device *dev,
275				struct devfreq *devfreq,
276				struct notifier_block *nb,
277				unsigned int list);
278struct devfreq *devfreq_get_devfreq_by_node(struct device_node *node);
279struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev,
280				const char *phandle_name, int index);
281#endif /* CONFIG_PM_DEVFREQ */
282
283/**
284 * struct devfreq_simple_ondemand_data - ``void *data`` fed to struct devfreq
285 *	and devfreq_add_device
286 * @upthreshold:	If the load is over this value, the frequency jumps.
287 *			Specify 0 to use the default. Valid value = 0 to 100.
288 * @downdifferential:	If the load is under upthreshold - downdifferential,
289 *			the governor may consider slowing the frequency down.
290 *			Specify 0 to use the default. Valid value = 0 to 100.
291 *			downdifferential < upthreshold must hold.
292 *
293 * If the fed devfreq_simple_ondemand_data pointer is NULL to the governor,
294 * the governor uses the default values.
295 */
296struct devfreq_simple_ondemand_data {
297	unsigned int upthreshold;
298	unsigned int downdifferential;
299};
300
301enum devfreq_parent_dev_type {
302	DEVFREQ_PARENT_DEV,
303	CPUFREQ_PARENT_DEV,
304};
305
306/**
307 * struct devfreq_passive_data - ``void *data`` fed to struct devfreq
308 *	and devfreq_add_device
309 * @parent:	the devfreq instance of parent device.
310 * @get_target_freq:	Optional callback, Returns desired operating frequency
311 *			for the device using passive governor. That is called
312 *			when passive governor should decide the next frequency
313 *			by using the new frequency of parent devfreq device
314 *			using governors except for passive governor.
315 *			If the devfreq device has the specific method to decide
316 *			the next frequency, should use this callback.
317 * @parent_type:	the parent type of the device.
318 * @this:		the devfreq instance of own device.
319 * @nb:			the notifier block for DEVFREQ_TRANSITION_NOTIFIER or
320 *			CPUFREQ_TRANSITION_NOTIFIER list.
321 * @cpu_data_list:	the list of cpu frequency data for all cpufreq_policy.
322 *
323 * The devfreq_passive_data have to set the devfreq instance of parent
324 * device with governors except for the passive governor. But, don't need to
325 * initialize the 'this' and 'nb' field because the devfreq core will handle
326 * them.
327 */
328struct devfreq_passive_data {
329	/* Should set the devfreq instance of parent device */
330	struct devfreq *parent;
331
332	/* Optional callback to decide the next frequency of passvice device */
333	int (*get_target_freq)(struct devfreq *this, unsigned long *freq);
334
335	/* Should set the type of parent device */
336	enum devfreq_parent_dev_type parent_type;
337
338	/* For passive governor's internal use. Don't need to set them */
339	struct devfreq *this;
340	struct notifier_block nb;
341	struct list_head cpu_data_list;
342};
343
344#if !defined(CONFIG_PM_DEVFREQ)
345static inline struct devfreq *devfreq_add_device(struct device *dev,
346					struct devfreq_dev_profile *profile,
347					const char *governor_name,
348					void *data)
349{
350	return ERR_PTR(-ENOSYS);
351}
352
353static inline int devfreq_remove_device(struct devfreq *devfreq)
354{
355	return 0;
356}
357
358static inline struct devfreq *devm_devfreq_add_device(struct device *dev,
359					struct devfreq_dev_profile *profile,
360					const char *governor_name,
361					void *data)
362{
363	return ERR_PTR(-ENOSYS);
364}
365
366static inline void devm_devfreq_remove_device(struct device *dev,
367					struct devfreq *devfreq)
368{
369}
370
371static inline int devfreq_suspend_device(struct devfreq *devfreq)
372{
373	return 0;
374}
375
376static inline int devfreq_resume_device(struct devfreq *devfreq)
377{
378	return 0;
379}
380
381static inline void devfreq_suspend(void) {}
382static inline void devfreq_resume(void) {}
383
384static inline struct dev_pm_opp *devfreq_recommended_opp(struct device *dev,
385					unsigned long *freq, u32 flags)
386{
387	return ERR_PTR(-EINVAL);
388}
389
390static inline int devfreq_register_opp_notifier(struct device *dev,
391					struct devfreq *devfreq)
392{
393	return -EINVAL;
394}
395
396static inline int devfreq_unregister_opp_notifier(struct device *dev,
397					struct devfreq *devfreq)
398{
399	return -EINVAL;
400}
401
402static inline int devm_devfreq_register_opp_notifier(struct device *dev,
403					struct devfreq *devfreq)
404{
405	return -EINVAL;
406}
407
408static inline void devm_devfreq_unregister_opp_notifier(struct device *dev,
409					struct devfreq *devfreq)
410{
411}
412
413static inline int devfreq_register_notifier(struct devfreq *devfreq,
414					struct notifier_block *nb,
415					unsigned int list)
416{
417	return 0;
418}
419
420static inline int devfreq_unregister_notifier(struct devfreq *devfreq,
421					struct notifier_block *nb,
422					unsigned int list)
423{
424	return 0;
425}
426
427static inline int devm_devfreq_register_notifier(struct device *dev,
428					struct devfreq *devfreq,
429					struct notifier_block *nb,
430					unsigned int list)
431{
432	return 0;
433}
434
435static inline void devm_devfreq_unregister_notifier(struct device *dev,
436					struct devfreq *devfreq,
437					struct notifier_block *nb,
438					unsigned int list)
439{
440}
441
442static inline struct devfreq *devfreq_get_devfreq_by_node(struct device_node *node)
443{
444	return ERR_PTR(-ENODEV);
445}
446
447static inline struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev,
448					const char *phandle_name, int index)
449{
450	return ERR_PTR(-ENODEV);
451}
452
453static inline int devfreq_update_stats(struct devfreq *df)
454{
455	return -EINVAL;
456}
457#endif /* CONFIG_PM_DEVFREQ */
458
459#endif /* __LINUX_DEVFREQ_H__ */