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