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MyungJoo Hama3c98b82011-10-02 00:19:15 +02001/*
2 * devfreq: Generic Dynamic Voltage and Frequency Scaling (DVFS) Framework
3 * for Non-CPU Devices.
4 *
5 * Copyright (C) 2011 Samsung Electronics
6 * MyungJoo Ham <myungjoo.ham@samsung.com>
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2 as
10 * published by the Free Software Foundation.
11 */
12
13#ifndef __LINUX_DEVFREQ_H__
14#define __LINUX_DEVFREQ_H__
15
16#include <linux/device.h>
17#include <linux/notifier.h>
18#include <linux/opp.h>
19
20#define DEVFREQ_NAME_LEN 16
21
22struct devfreq;
23
24/**
25 * struct devfreq_dev_status - Data given from devfreq user device to
26 * governors. Represents the performance
27 * statistics.
Nishanth Menone09651f2012-10-29 08:02:23 -050028 * @total_time: The total time represented by this instance of
MyungJoo Hama3c98b82011-10-02 00:19:15 +020029 * devfreq_dev_status
Nishanth Menone09651f2012-10-29 08:02:23 -050030 * @busy_time: The time that the device was working among the
MyungJoo Hama3c98b82011-10-02 00:19:15 +020031 * total_time.
Nishanth Menone09651f2012-10-29 08:02:23 -050032 * @current_frequency: The operating frequency.
33 * @private_data: An entry not specified by the devfreq framework.
MyungJoo Hama3c98b82011-10-02 00:19:15 +020034 * A device and a specific governor may have their
35 * own protocol with private_data. However, because
36 * this is governor-specific, a governor using this
37 * will be only compatible with devices aware of it.
38 */
39struct devfreq_dev_status {
40 /* both since the last measure */
41 unsigned long total_time;
42 unsigned long busy_time;
43 unsigned long current_frequency;
Jonathan Corbet1a51cfd2011-11-07 23:54:53 +010044 void *private_data;
MyungJoo Hama3c98b82011-10-02 00:19:15 +020045};
46
MyungJoo Hamab5f2992012-03-16 21:54:53 +010047/*
48 * The resulting frequency should be at most this. (this bound is the
49 * least upper bound; thus, the resulting freq should be lower or same)
50 * If the flag is not set, the resulting frequency should be at most the
51 * bound (greatest lower bound)
52 */
53#define DEVFREQ_FLAG_LEAST_UPPER_BOUND 0x1
54
MyungJoo Hama3c98b82011-10-02 00:19:15 +020055/**
56 * struct devfreq_dev_profile - Devfreq's user device profile
Nishanth Menone09651f2012-10-29 08:02:23 -050057 * @initial_freq: The operating frequency when devfreq_add_device() is
MyungJoo Hama3c98b82011-10-02 00:19:15 +020058 * called.
Nishanth Menone09651f2012-10-29 08:02:23 -050059 * @polling_ms: The polling interval in ms. 0 disables polling.
60 * @target: The device should set its operating frequency at
MyungJoo Hama3c98b82011-10-02 00:19:15 +020061 * freq or lowest-upper-than-freq value. If freq is
62 * higher than any operable frequency, set maximum.
63 * Before returning, target function should set
64 * freq at the current frequency.
MyungJoo Hamab5f2992012-03-16 21:54:53 +010065 * The "flags" parameter's possible values are
66 * explained above with "DEVFREQ_FLAG_*" macros.
Nishanth Menone09651f2012-10-29 08:02:23 -050067 * @get_dev_status: The device should provide the current performance
MyungJoo Hama3c98b82011-10-02 00:19:15 +020068 * status to devfreq, which is used by governors.
Nishanth Menone09651f2012-10-29 08:02:23 -050069 * @get_cur_freq: The device should provide the current frequency
Rajagopal Venkat7f98a902012-10-26 01:50:26 +020070 * at which it is operating.
Nishanth Menone09651f2012-10-29 08:02:23 -050071 * @exit: An optional callback that is called when devfreq
MyungJoo Hama3c98b82011-10-02 00:19:15 +020072 * is removing the devfreq object due to error or
73 * from devfreq_remove_device() call. If the user
74 * has registered devfreq->nb at a notifier-head,
75 * this is the time to unregister it.
Jonghwa Leee552bba2012-08-23 20:00:46 +090076 * @freq_table: Optional list of frequencies to support statistics.
77 * @max_state: The size of freq_table.
MyungJoo Hama3c98b82011-10-02 00:19:15 +020078 */
79struct devfreq_dev_profile {
80 unsigned long initial_freq;
81 unsigned int polling_ms;
82
MyungJoo Hamab5f2992012-03-16 21:54:53 +010083 int (*target)(struct device *dev, unsigned long *freq, u32 flags);
MyungJoo Hama3c98b82011-10-02 00:19:15 +020084 int (*get_dev_status)(struct device *dev,
85 struct devfreq_dev_status *stat);
Rajagopal Venkat7f98a902012-10-26 01:50:26 +020086 int (*get_cur_freq)(struct device *dev, unsigned long *freq);
MyungJoo Hama3c98b82011-10-02 00:19:15 +020087 void (*exit)(struct device *dev);
Jonghwa Leee552bba2012-08-23 20:00:46 +090088
89 unsigned int *freq_table;
90 unsigned int max_state;
MyungJoo Hama3c98b82011-10-02 00:19:15 +020091};
92
93/**
94 * struct devfreq_governor - Devfreq policy governor
Nishanth Menon3aa173b2012-10-29 15:01:43 -050095 * @node: list node - contains registered devfreq governors
Nishanth Menone09651f2012-10-29 08:02:23 -050096 * @name: Governor's name
97 * @get_target_freq: Returns desired operating frequency for the device.
MyungJoo Hama3c98b82011-10-02 00:19:15 +020098 * Basically, get_target_freq will run
99 * devfreq_dev_profile.get_dev_status() to get the
100 * status of the device (load = busy_time / total_time).
101 * If no_central_polling is set, this callback is called
102 * only with update_devfreq() notified by OPP.
Nishanth Menone09651f2012-10-29 08:02:23 -0500103 * @event_handler: Callback for devfreq core framework to notify events
Rajagopal Venkat7e6fdd42012-10-26 01:50:09 +0200104 * to governors. Events include per device governor
105 * init and exit, opp changes out of devfreq, suspend
106 * and resume of per device devfreq during device idle.
MyungJoo Hama3c98b82011-10-02 00:19:15 +0200107 *
108 * Note that the callbacks are called with devfreq->lock locked by devfreq.
109 */
110struct devfreq_governor {
Nishanth Menon3aa173b2012-10-29 15:01:43 -0500111 struct list_head node;
112
MyungJoo Hama3c98b82011-10-02 00:19:15 +0200113 const char name[DEVFREQ_NAME_LEN];
114 int (*get_target_freq)(struct devfreq *this, unsigned long *freq);
Rajagopal Venkat7e6fdd42012-10-26 01:50:09 +0200115 int (*event_handler)(struct devfreq *devfreq,
116 unsigned int event, void *data);
MyungJoo Hama3c98b82011-10-02 00:19:15 +0200117};
118
119/**
120 * struct devfreq - Device devfreq structure
Nishanth Menone09651f2012-10-29 08:02:23 -0500121 * @node: list node - contains the devices with devfreq that have been
MyungJoo Hama3c98b82011-10-02 00:19:15 +0200122 * registered.
Nishanth Menone09651f2012-10-29 08:02:23 -0500123 * @lock: a mutex to protect accessing devfreq.
124 * @dev: device registered by devfreq class. dev.parent is the device
MyungJoo Hama3c98b82011-10-02 00:19:15 +0200125 * using devfreq.
Nishanth Menone09651f2012-10-29 08:02:23 -0500126 * @profile: device-specific devfreq profile
127 * @governor: method how to choose frequency based on the usage.
Nishanth Menon1b5c1be2012-10-29 15:01:45 -0500128 * @governor_name: devfreq governor name for use with this devfreq
Nishanth Menone09651f2012-10-29 08:02:23 -0500129 * @nb: notifier block used to notify devfreq object that it should
MyungJoo Hama3c98b82011-10-02 00:19:15 +0200130 * reevaluate operable frequencies. Devfreq users may use
131 * devfreq.nb to the corresponding register notifier call chain.
Nishanth Menone09651f2012-10-29 08:02:23 -0500132 * @work: delayed work for load monitoring.
133 * @previous_freq: previously configured frequency value.
134 * @data: Private data of the governor. The devfreq framework does not
MyungJoo Hama3c98b82011-10-02 00:19:15 +0200135 * touch this.
Nishanth Menone09651f2012-10-29 08:02:23 -0500136 * @min_freq: Limit minimum frequency requested by user (0: none)
137 * @max_freq: Limit maximum frequency requested by user (0: none)
138 * @stop_polling: devfreq polling status of a device.
Jonghwa Leee552bba2012-08-23 20:00:46 +0900139 * @total_trans: Number of devfreq transitions
140 * @trans_table: Statistics of devfreq transitions
141 * @time_in_state: Statistics of devfreq states
142 * @last_stat_updated: The last time stat updated
MyungJoo Hama3c98b82011-10-02 00:19:15 +0200143 *
144 * This structure stores the devfreq information for a give device.
145 *
146 * Note that when a governor accesses entries in struct devfreq in its
147 * functions except for the context of callbacks defined in struct
148 * devfreq_governor, the governor should protect its access with the
149 * struct mutex lock in struct devfreq. A governor may use this mutex
150 * to protect its own private data in void *data as well.
151 */
152struct devfreq {
153 struct list_head node;
154
155 struct mutex lock;
156 struct device dev;
157 struct devfreq_dev_profile *profile;
158 const struct devfreq_governor *governor;
Nishanth Menon1b5c1be2012-10-29 15:01:45 -0500159 char governor_name[DEVFREQ_NAME_LEN];
MyungJoo Hama3c98b82011-10-02 00:19:15 +0200160 struct notifier_block nb;
Rajagopal Venkat7e6fdd42012-10-26 01:50:09 +0200161 struct delayed_work work;
MyungJoo Hama3c98b82011-10-02 00:19:15 +0200162
MyungJoo Hama3c98b82011-10-02 00:19:15 +0200163 unsigned long previous_freq;
MyungJoo Hama3c98b82011-10-02 00:19:15 +0200164
165 void *data; /* private data for governors */
166
MyungJoo Ham6530b9de2011-12-09 16:42:19 +0900167 unsigned long min_freq;
168 unsigned long max_freq;
Rajagopal Venkat7e6fdd42012-10-26 01:50:09 +0200169 bool stop_polling;
Jonghwa Leee552bba2012-08-23 20:00:46 +0900170
171 /* information for device freqeuncy transition */
172 unsigned int total_trans;
173 unsigned int *trans_table;
174 unsigned long *time_in_state;
175 unsigned long last_stat_updated;
MyungJoo Hama3c98b82011-10-02 00:19:15 +0200176};
177
178#if defined(CONFIG_PM_DEVFREQ)
179extern struct devfreq *devfreq_add_device(struct device *dev,
180 struct devfreq_dev_profile *profile,
Nishanth Menon1b5c1be2012-10-29 15:01:45 -0500181 const char *governor_name,
MyungJoo Hama3c98b82011-10-02 00:19:15 +0200182 void *data);
183extern int devfreq_remove_device(struct devfreq *devfreq);
Rajagopal Venkat206c30c2012-10-26 01:50:18 +0200184extern int devfreq_suspend_device(struct devfreq *devfreq);
185extern int devfreq_resume_device(struct devfreq *devfreq);
MyungJoo Hama3c98b82011-10-02 00:19:15 +0200186
187/* Helper functions for devfreq user device driver with OPP. */
188extern struct opp *devfreq_recommended_opp(struct device *dev,
MyungJoo Hamab5f2992012-03-16 21:54:53 +0100189 unsigned long *freq, u32 flags);
MyungJoo Hama3c98b82011-10-02 00:19:15 +0200190extern int devfreq_register_opp_notifier(struct device *dev,
191 struct devfreq *devfreq);
192extern int devfreq_unregister_opp_notifier(struct device *dev,
193 struct devfreq *devfreq);
194
MyungJoo Ham883d5882012-11-21 17:17:11 +0900195#if IS_ENABLED(CONFIG_DEVFREQ_GOV_SIMPLE_ONDEMAND)
MyungJoo Hamce26c5b2011-10-02 00:19:34 +0200196/**
197 * struct devfreq_simple_ondemand_data - void *data fed to struct devfreq
198 * and devfreq_add_device
Nishanth Menone09651f2012-10-29 08:02:23 -0500199 * @upthreshold: If the load is over this value, the frequency jumps.
MyungJoo Hamce26c5b2011-10-02 00:19:34 +0200200 * Specify 0 to use the default. Valid value = 0 to 100.
Nishanth Menone09651f2012-10-29 08:02:23 -0500201 * @downdifferential: If the load is under upthreshold - downdifferential,
MyungJoo Hamce26c5b2011-10-02 00:19:34 +0200202 * the governor may consider slowing the frequency down.
203 * Specify 0 to use the default. Valid value = 0 to 100.
204 * downdifferential < upthreshold must hold.
205 *
206 * If the fed devfreq_simple_ondemand_data pointer is NULL to the governor,
207 * the governor uses the default values.
208 */
209struct devfreq_simple_ondemand_data {
210 unsigned int upthreshold;
211 unsigned int downdifferential;
212};
213#endif
214
MyungJoo Hama3c98b82011-10-02 00:19:15 +0200215#else /* !CONFIG_PM_DEVFREQ */
216static struct devfreq *devfreq_add_device(struct device *dev,
217 struct devfreq_dev_profile *profile,
Nishanth Menon1b5c1be2012-10-29 15:01:45 -0500218 const char *governor_name,
MyungJoo Hama95e1f52012-01-11 17:44:28 +0900219 void *data)
MyungJoo Hama3c98b82011-10-02 00:19:15 +0200220{
221 return NULL;
222}
223
MyungJoo Hama95e1f52012-01-11 17:44:28 +0900224static int devfreq_remove_device(struct devfreq *devfreq)
MyungJoo Hama3c98b82011-10-02 00:19:15 +0200225{
226 return 0;
227}
228
Rajagopal Venkat206c30c2012-10-26 01:50:18 +0200229static int devfreq_suspend_device(struct devfreq *devfreq)
230{
231 return 0;
232}
233
234static int devfreq_resume_device(struct devfreq *devfreq)
235{
236 return 0;
237}
238
MyungJoo Hama3c98b82011-10-02 00:19:15 +0200239static struct opp *devfreq_recommended_opp(struct device *dev,
MyungJoo Hamab5f2992012-03-16 21:54:53 +0100240 unsigned long *freq, u32 flags)
MyungJoo Hama3c98b82011-10-02 00:19:15 +0200241{
242 return -EINVAL;
243}
244
245static int devfreq_register_opp_notifier(struct device *dev,
246 struct devfreq *devfreq)
247{
248 return -EINVAL;
249}
250
251static int devfreq_unregister_opp_notifier(struct device *dev,
252 struct devfreq *devfreq)
253{
254 return -EINVAL;
255}
256
MyungJoo Hama3c98b82011-10-02 00:19:15 +0200257#endif /* CONFIG_PM_DEVFREQ */
258
259#endif /* __LINUX_DEVFREQ_H__ */