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 */
33 enum devfreq_timer {
34 	DEVFREQ_TIMER_DEFERRABLE = 0,
35 	DEVFREQ_TIMER_DELAYED,
36 	DEVFREQ_TIMER_NUM,
37 };
38 
39 struct devfreq;
40 struct devfreq_governor;
41 struct devfreq_cpu_data;
42 struct 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  */
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;
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  */
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;
112 
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);
118 
119 	unsigned long *freq_table;
120 	unsigned int max_state;
121 };
122 
123 /**
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.
129  */
130 struct devfreq_stats {
131 	unsigned int total_trans;
132 	unsigned int *trans_table;
133 	u64 *time_in_state;
134 	u64 last_update;
135 };
136 
137 /**
138  * struct devfreq - Device devfreq structure
139  * @node:	list node - contains the devices with devfreq that have been
140  *		registered.
141  * @lock:	a mutex to protect accessing devfreq.
142  * @dev:	device registered by devfreq class. dev.parent is the device
143  *		using devfreq.
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  * @freq_table:		current frequency table used by the devfreq driver.
152  * @max_state:		count of entry present in the frequency table.
153  * @previous_freq:	previously configured frequency value.
154  * @last_status:	devfreq user device info, performance statistics
155  * @data:	devfreq driver pass to governors, governor should not change it.
156  * @governor_data:	private data for governors, devfreq core doesn't touch it.
157  * @user_min_freq_req:	PM QoS minimum frequency request from user (via sysfs)
158  * @user_max_freq_req:	PM QoS maximum frequency request from user (via sysfs)
159  * @scaling_min_freq:	Limit minimum frequency requested by OPP interface
160  * @scaling_max_freq:	Limit maximum frequency requested by OPP interface
161  * @stop_polling:	 devfreq polling status of a device.
162  * @suspend_freq:	 frequency of a device set during suspend phase.
163  * @resume_freq:	 frequency of a device set in resume phase.
164  * @suspend_count:	 suspend requests counter for a device.
165  * @stats:	Statistics of devfreq device behavior
166  * @transition_notifier_list: list head of DEVFREQ_TRANSITION_NOTIFIER notifier
167  * @cdev:	Cooling device pointer if the devfreq has cooling property
168  * @nb_min:		Notifier block for DEV_PM_QOS_MIN_FREQUENCY
169  * @nb_max:		Notifier block for DEV_PM_QOS_MAX_FREQUENCY
170  *
171  * This structure stores the devfreq information for a given device.
172  *
173  * Note that when a governor accesses entries in struct devfreq in its
174  * functions except for the context of callbacks defined in struct
175  * devfreq_governor, the governor should protect its access with the
176  * struct mutex lock in struct devfreq. A governor may use this mutex
177  * to protect its own private data in ``void *data`` as well.
178  */
179 struct devfreq {
180 	struct list_head node;
181 
182 	struct mutex lock;
183 	struct device dev;
184 	struct devfreq_dev_profile *profile;
185 	const struct devfreq_governor *governor;
186 	struct opp_table *opp_table;
187 	struct notifier_block nb;
188 	struct delayed_work work;
189 
190 	unsigned long *freq_table;
191 	unsigned int max_state;
192 
193 	unsigned long previous_freq;
194 	struct devfreq_dev_status last_status;
195 
196 	void *data;
197 	void *governor_data;
198 
199 	struct dev_pm_qos_request user_min_freq_req;
200 	struct dev_pm_qos_request user_max_freq_req;
201 	unsigned long scaling_min_freq;
202 	unsigned long scaling_max_freq;
203 	bool stop_polling;
204 
205 	unsigned long suspend_freq;
206 	unsigned long resume_freq;
207 	atomic_t suspend_count;
208 
209 	/* information for device frequency transitions */
210 	struct devfreq_stats stats;
211 
212 	struct srcu_notifier_head transition_notifier_list;
213 
214 	/* Pointer to the cooling device if used for thermal mitigation */
215 	struct thermal_cooling_device *cdev;
216 
217 	struct notifier_block nb_min;
218 	struct notifier_block nb_max;
219 };
220 
221 struct devfreq_freqs {
222 	unsigned long old;
223 	unsigned long new;
224 };
225 
226 #if defined(CONFIG_PM_DEVFREQ)
227 struct devfreq *devfreq_add_device(struct device *dev,
228 				struct devfreq_dev_profile *profile,
229 				const char *governor_name,
230 				void *data);
231 int devfreq_remove_device(struct devfreq *devfreq);
232 struct devfreq *devm_devfreq_add_device(struct device *dev,
233 				struct devfreq_dev_profile *profile,
234 				const char *governor_name,
235 				void *data);
236 void devm_devfreq_remove_device(struct device *dev, struct devfreq *devfreq);
237 
238 /* Supposed to be called by PM callbacks */
239 int devfreq_suspend_device(struct devfreq *devfreq);
240 int devfreq_resume_device(struct devfreq *devfreq);
241 
242 void devfreq_suspend(void);
243 void devfreq_resume(void);
244 
245 /* update_devfreq() - Reevaluate the device and configure frequency */
246 int update_devfreq(struct devfreq *devfreq);
247 
248 /* Helper functions for devfreq user device driver with OPP. */
249 struct dev_pm_opp *devfreq_recommended_opp(struct device *dev,
250 				unsigned long *freq, u32 flags);
251 int devfreq_register_opp_notifier(struct device *dev,
252 				struct devfreq *devfreq);
253 int devfreq_unregister_opp_notifier(struct device *dev,
254 				struct devfreq *devfreq);
255 int devm_devfreq_register_opp_notifier(struct device *dev,
256 				struct devfreq *devfreq);
257 void devm_devfreq_unregister_opp_notifier(struct device *dev,
258 				struct devfreq *devfreq);
259 int devfreq_register_notifier(struct devfreq *devfreq,
260 				struct notifier_block *nb,
261 				unsigned int list);
262 int devfreq_unregister_notifier(struct devfreq *devfreq,
263 				struct notifier_block *nb,
264 				unsigned int list);
265 int devm_devfreq_register_notifier(struct device *dev,
266 				struct devfreq *devfreq,
267 				struct notifier_block *nb,
268 				unsigned int list);
269 void devm_devfreq_unregister_notifier(struct device *dev,
270 				struct devfreq *devfreq,
271 				struct notifier_block *nb,
272 				unsigned int list);
273 struct devfreq *devfreq_get_devfreq_by_node(struct device_node *node);
274 struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev,
275 				const char *phandle_name, int index);
276 #endif /* CONFIG_PM_DEVFREQ */
277 
278 /**
279  * struct devfreq_simple_ondemand_data - ``void *data`` fed to struct devfreq
280  *	and devfreq_add_device
281  * @upthreshold:	If the load is over this value, the frequency jumps.
282  *			Specify 0 to use the default. Valid value = 0 to 100.
283  * @downdifferential:	If the load is under upthreshold - downdifferential,
284  *			the governor may consider slowing the frequency down.
285  *			Specify 0 to use the default. Valid value = 0 to 100.
286  *			downdifferential < upthreshold must hold.
287  *
288  * If the fed devfreq_simple_ondemand_data pointer is NULL to the governor,
289  * the governor uses the default values.
290  */
291 struct devfreq_simple_ondemand_data {
292 	unsigned int upthreshold;
293 	unsigned int downdifferential;
294 };
295 
296 enum devfreq_parent_dev_type {
297 	DEVFREQ_PARENT_DEV,
298 	CPUFREQ_PARENT_DEV,
299 };
300 
301 /**
302  * struct devfreq_passive_data - ``void *data`` fed to struct devfreq
303  *	and devfreq_add_device
304  * @parent:	the devfreq instance of parent device.
305  * @get_target_freq:	Optional callback, Returns desired operating frequency
306  *			for the device using passive governor. That is called
307  *			when passive governor should decide the next frequency
308  *			by using the new frequency of parent devfreq device
309  *			using governors except for passive governor.
310  *			If the devfreq device has the specific method to decide
311  *			the next frequency, should use this callback.
312  * @parent_type:	the parent type of the device.
313  * @this:		the devfreq instance of own device.
314  * @nb:			the notifier block for DEVFREQ_TRANSITION_NOTIFIER or
315  *			CPUFREQ_TRANSITION_NOTIFIER list.
316  * @cpu_data_list:	the list of cpu frequency data for all cpufreq_policy.
317  *
318  * The devfreq_passive_data have to set the devfreq instance of parent
319  * device with governors except for the passive governor. But, don't need to
320  * initialize the 'this' and 'nb' field because the devfreq core will handle
321  * them.
322  */
323 struct devfreq_passive_data {
324 	/* Should set the devfreq instance of parent device */
325 	struct devfreq *parent;
326 
327 	/* Optional callback to decide the next frequency of passvice device */
328 	int (*get_target_freq)(struct devfreq *this, unsigned long *freq);
329 
330 	/* Should set the type of parent device */
331 	enum devfreq_parent_dev_type parent_type;
332 
333 	/* For passive governor's internal use. Don't need to set them */
334 	struct devfreq *this;
335 	struct notifier_block nb;
336 	struct list_head cpu_data_list;
337 };
338 
339 #if !defined(CONFIG_PM_DEVFREQ)
devfreq_add_device(struct device * dev,struct devfreq_dev_profile * profile,const char * governor_name,void * data)340 static inline struct devfreq *devfreq_add_device(struct device *dev,
341 					struct devfreq_dev_profile *profile,
342 					const char *governor_name,
343 					void *data)
344 {
345 	return ERR_PTR(-ENOSYS);
346 }
347 
devfreq_remove_device(struct devfreq * devfreq)348 static inline int devfreq_remove_device(struct devfreq *devfreq)
349 {
350 	return 0;
351 }
352 
devm_devfreq_add_device(struct device * dev,struct devfreq_dev_profile * profile,const char * governor_name,void * data)353 static inline struct devfreq *devm_devfreq_add_device(struct device *dev,
354 					struct devfreq_dev_profile *profile,
355 					const char *governor_name,
356 					void *data)
357 {
358 	return ERR_PTR(-ENOSYS);
359 }
360 
devm_devfreq_remove_device(struct device * dev,struct devfreq * devfreq)361 static inline void devm_devfreq_remove_device(struct device *dev,
362 					struct devfreq *devfreq)
363 {
364 }
365 
devfreq_suspend_device(struct devfreq * devfreq)366 static inline int devfreq_suspend_device(struct devfreq *devfreq)
367 {
368 	return 0;
369 }
370 
devfreq_resume_device(struct devfreq * devfreq)371 static inline int devfreq_resume_device(struct devfreq *devfreq)
372 {
373 	return 0;
374 }
375 
devfreq_suspend(void)376 static inline void devfreq_suspend(void) {}
devfreq_resume(void)377 static inline void devfreq_resume(void) {}
378 
devfreq_recommended_opp(struct device * dev,unsigned long * freq,u32 flags)379 static inline struct dev_pm_opp *devfreq_recommended_opp(struct device *dev,
380 					unsigned long *freq, u32 flags)
381 {
382 	return ERR_PTR(-EINVAL);
383 }
384 
devfreq_register_opp_notifier(struct device * dev,struct devfreq * devfreq)385 static inline int devfreq_register_opp_notifier(struct device *dev,
386 					struct devfreq *devfreq)
387 {
388 	return -EINVAL;
389 }
390 
devfreq_unregister_opp_notifier(struct device * dev,struct devfreq * devfreq)391 static inline int devfreq_unregister_opp_notifier(struct device *dev,
392 					struct devfreq *devfreq)
393 {
394 	return -EINVAL;
395 }
396 
devm_devfreq_register_opp_notifier(struct device * dev,struct devfreq * devfreq)397 static inline int devm_devfreq_register_opp_notifier(struct device *dev,
398 					struct devfreq *devfreq)
399 {
400 	return -EINVAL;
401 }
402 
devm_devfreq_unregister_opp_notifier(struct device * dev,struct devfreq * devfreq)403 static inline void devm_devfreq_unregister_opp_notifier(struct device *dev,
404 					struct devfreq *devfreq)
405 {
406 }
407 
devfreq_register_notifier(struct devfreq * devfreq,struct notifier_block * nb,unsigned int list)408 static inline int devfreq_register_notifier(struct devfreq *devfreq,
409 					struct notifier_block *nb,
410 					unsigned int list)
411 {
412 	return 0;
413 }
414 
devfreq_unregister_notifier(struct devfreq * devfreq,struct notifier_block * nb,unsigned int list)415 static inline int devfreq_unregister_notifier(struct devfreq *devfreq,
416 					struct notifier_block *nb,
417 					unsigned int list)
418 {
419 	return 0;
420 }
421 
devm_devfreq_register_notifier(struct device * dev,struct devfreq * devfreq,struct notifier_block * nb,unsigned int list)422 static inline int devm_devfreq_register_notifier(struct device *dev,
423 					struct devfreq *devfreq,
424 					struct notifier_block *nb,
425 					unsigned int list)
426 {
427 	return 0;
428 }
429 
devm_devfreq_unregister_notifier(struct device * dev,struct devfreq * devfreq,struct notifier_block * nb,unsigned int list)430 static inline void devm_devfreq_unregister_notifier(struct device *dev,
431 					struct devfreq *devfreq,
432 					struct notifier_block *nb,
433 					unsigned int list)
434 {
435 }
436 
devfreq_get_devfreq_by_node(struct device_node * node)437 static inline struct devfreq *devfreq_get_devfreq_by_node(struct device_node *node)
438 {
439 	return ERR_PTR(-ENODEV);
440 }
441 
devfreq_get_devfreq_by_phandle(struct device * dev,const char * phandle_name,int index)442 static inline struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev,
443 					const char *phandle_name, int index)
444 {
445 	return ERR_PTR(-ENODEV);
446 }
447 
devfreq_update_stats(struct devfreq * df)448 static inline int devfreq_update_stats(struct devfreq *df)
449 {
450 	return -EINVAL;
451 }
452 #endif /* CONFIG_PM_DEVFREQ */
453 
454 #endif /* __LINUX_DEVFREQ_H__ */
455