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a3c98b8b MH |
1 | /* |
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 | ||
22 | struct devfreq; | |
23 | ||
24 | /** | |
25 | * struct devfreq_dev_status - Data given from devfreq user device to | |
26 | * governors. Represents the performance | |
27 | * statistics. | |
28 | * @total_time The total time represented by this instance of | |
29 | * devfreq_dev_status | |
30 | * @busy_time The time that the device was working among the | |
31 | * total_time. | |
32 | * @current_frequency The operating frequency. | |
33 | * @private_data An entry not specified by the devfreq framework. | |
34 | * 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 | */ | |
39 | struct devfreq_dev_status { | |
40 | /* both since the last measure */ | |
41 | unsigned long total_time; | |
42 | unsigned long busy_time; | |
43 | unsigned long current_frequency; | |
1a51cfdc | 44 | void *private_data; |
a3c98b8b MH |
45 | }; |
46 | ||
ab5f299f MH |
47 | /* |
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 | ||
a3c98b8b MH |
55 | /** |
56 | * struct devfreq_dev_profile - Devfreq's user device profile | |
57 | * @initial_freq The operating frequency when devfreq_add_device() is | |
58 | * called. | |
59 | * @polling_ms The polling interval in ms. 0 disables polling. | |
60 | * @target The device should set its operating frequency at | |
61 | * 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. | |
ab5f299f MH |
65 | * The "flags" parameter's possible values are |
66 | * explained above with "DEVFREQ_FLAG_*" macros. | |
a3c98b8b MH |
67 | * @get_dev_status The device should provide the current performance |
68 | * status to devfreq, which is used by governors. | |
7f98a905 RV |
69 | * @get_cur_freq The device should provide the current frequency |
70 | * at which it is operating. | |
a3c98b8b MH |
71 | * @exit An optional callback that is called when devfreq |
72 | * 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. | |
76 | */ | |
77 | struct devfreq_dev_profile { | |
78 | unsigned long initial_freq; | |
79 | unsigned int polling_ms; | |
80 | ||
ab5f299f | 81 | int (*target)(struct device *dev, unsigned long *freq, u32 flags); |
a3c98b8b MH |
82 | int (*get_dev_status)(struct device *dev, |
83 | struct devfreq_dev_status *stat); | |
7f98a905 | 84 | int (*get_cur_freq)(struct device *dev, unsigned long *freq); |
a3c98b8b MH |
85 | void (*exit)(struct device *dev); |
86 | }; | |
87 | ||
88 | /** | |
89 | * struct devfreq_governor - Devfreq policy governor | |
90 | * @name Governor's name | |
91 | * @get_target_freq Returns desired operating frequency for the device. | |
92 | * Basically, get_target_freq will run | |
93 | * devfreq_dev_profile.get_dev_status() to get the | |
94 | * status of the device (load = busy_time / total_time). | |
95 | * If no_central_polling is set, this callback is called | |
96 | * only with update_devfreq() notified by OPP. | |
7e6fdd4b RV |
97 | * @event_handler Callback for devfreq core framework to notify events |
98 | * to governors. Events include per device governor | |
99 | * init and exit, opp changes out of devfreq, suspend | |
100 | * and resume of per device devfreq during device idle. | |
a3c98b8b MH |
101 | * |
102 | * Note that the callbacks are called with devfreq->lock locked by devfreq. | |
103 | */ | |
104 | struct devfreq_governor { | |
105 | const char name[DEVFREQ_NAME_LEN]; | |
106 | int (*get_target_freq)(struct devfreq *this, unsigned long *freq); | |
7e6fdd4b RV |
107 | int (*event_handler)(struct devfreq *devfreq, |
108 | unsigned int event, void *data); | |
a3c98b8b MH |
109 | }; |
110 | ||
111 | /** | |
112 | * struct devfreq - Device devfreq structure | |
113 | * @node list node - contains the devices with devfreq that have been | |
114 | * registered. | |
115 | * @lock a mutex to protect accessing devfreq. | |
116 | * @dev device registered by devfreq class. dev.parent is the device | |
117 | * using devfreq. | |
118 | * @profile device-specific devfreq profile | |
119 | * @governor method how to choose frequency based on the usage. | |
120 | * @nb notifier block used to notify devfreq object that it should | |
121 | * reevaluate operable frequencies. Devfreq users may use | |
122 | * devfreq.nb to the corresponding register notifier call chain. | |
7e6fdd4b | 123 | * @work delayed work for load monitoring. |
a3c98b8b | 124 | * @previous_freq previously configured frequency value. |
a3c98b8b MH |
125 | * @data Private data of the governor. The devfreq framework does not |
126 | * touch this. | |
6530b9de MH |
127 | * @min_freq Limit minimum frequency requested by user (0: none) |
128 | * @max_freq Limit maximum frequency requested by user (0: none) | |
7e6fdd4b | 129 | * @stop_polling devfreq polling status of a device. |
a3c98b8b MH |
130 | * |
131 | * This structure stores the devfreq information for a give device. | |
132 | * | |
133 | * Note that when a governor accesses entries in struct devfreq in its | |
134 | * functions except for the context of callbacks defined in struct | |
135 | * devfreq_governor, the governor should protect its access with the | |
136 | * struct mutex lock in struct devfreq. A governor may use this mutex | |
137 | * to protect its own private data in void *data as well. | |
138 | */ | |
139 | struct devfreq { | |
140 | struct list_head node; | |
141 | ||
142 | struct mutex lock; | |
143 | struct device dev; | |
144 | struct devfreq_dev_profile *profile; | |
145 | const struct devfreq_governor *governor; | |
146 | struct notifier_block nb; | |
7e6fdd4b | 147 | struct delayed_work work; |
a3c98b8b | 148 | |
a3c98b8b | 149 | unsigned long previous_freq; |
a3c98b8b MH |
150 | |
151 | void *data; /* private data for governors */ | |
152 | ||
6530b9de MH |
153 | unsigned long min_freq; |
154 | unsigned long max_freq; | |
7e6fdd4b | 155 | bool stop_polling; |
a3c98b8b MH |
156 | }; |
157 | ||
158 | #if defined(CONFIG_PM_DEVFREQ) | |
159 | extern struct devfreq *devfreq_add_device(struct device *dev, | |
160 | struct devfreq_dev_profile *profile, | |
161 | const struct devfreq_governor *governor, | |
162 | void *data); | |
163 | extern int devfreq_remove_device(struct devfreq *devfreq); | |
206c30cf RV |
164 | extern int devfreq_suspend_device(struct devfreq *devfreq); |
165 | extern int devfreq_resume_device(struct devfreq *devfreq); | |
a3c98b8b MH |
166 | |
167 | /* Helper functions for devfreq user device driver with OPP. */ | |
168 | extern struct opp *devfreq_recommended_opp(struct device *dev, | |
ab5f299f | 169 | unsigned long *freq, u32 flags); |
a3c98b8b MH |
170 | extern int devfreq_register_opp_notifier(struct device *dev, |
171 | struct devfreq *devfreq); | |
172 | extern int devfreq_unregister_opp_notifier(struct device *dev, | |
173 | struct devfreq *devfreq); | |
174 | ||
ce26c5bb MH |
175 | #ifdef CONFIG_DEVFREQ_GOV_POWERSAVE |
176 | extern const struct devfreq_governor devfreq_powersave; | |
177 | #endif | |
178 | #ifdef CONFIG_DEVFREQ_GOV_PERFORMANCE | |
179 | extern const struct devfreq_governor devfreq_performance; | |
180 | #endif | |
181 | #ifdef CONFIG_DEVFREQ_GOV_USERSPACE | |
182 | extern const struct devfreq_governor devfreq_userspace; | |
183 | #endif | |
184 | #ifdef CONFIG_DEVFREQ_GOV_SIMPLE_ONDEMAND | |
185 | extern const struct devfreq_governor devfreq_simple_ondemand; | |
186 | /** | |
187 | * struct devfreq_simple_ondemand_data - void *data fed to struct devfreq | |
188 | * and devfreq_add_device | |
189 | * @ upthreshold If the load is over this value, the frequency jumps. | |
190 | * Specify 0 to use the default. Valid value = 0 to 100. | |
191 | * @ downdifferential If the load is under upthreshold - downdifferential, | |
192 | * the governor may consider slowing the frequency down. | |
193 | * Specify 0 to use the default. Valid value = 0 to 100. | |
194 | * downdifferential < upthreshold must hold. | |
195 | * | |
196 | * If the fed devfreq_simple_ondemand_data pointer is NULL to the governor, | |
197 | * the governor uses the default values. | |
198 | */ | |
199 | struct devfreq_simple_ondemand_data { | |
200 | unsigned int upthreshold; | |
201 | unsigned int downdifferential; | |
202 | }; | |
203 | #endif | |
204 | ||
a3c98b8b MH |
205 | #else /* !CONFIG_PM_DEVFREQ */ |
206 | static struct devfreq *devfreq_add_device(struct device *dev, | |
207 | struct devfreq_dev_profile *profile, | |
208 | struct devfreq_governor *governor, | |
a95e1f5d | 209 | void *data) |
a3c98b8b MH |
210 | { |
211 | return NULL; | |
212 | } | |
213 | ||
a95e1f5d | 214 | static int devfreq_remove_device(struct devfreq *devfreq) |
a3c98b8b MH |
215 | { |
216 | return 0; | |
217 | } | |
218 | ||
206c30cf RV |
219 | static int devfreq_suspend_device(struct devfreq *devfreq) |
220 | { | |
221 | return 0; | |
222 | } | |
223 | ||
224 | static int devfreq_resume_device(struct devfreq *devfreq) | |
225 | { | |
226 | return 0; | |
227 | } | |
228 | ||
a3c98b8b | 229 | static struct opp *devfreq_recommended_opp(struct device *dev, |
ab5f299f | 230 | unsigned long *freq, u32 flags) |
a3c98b8b MH |
231 | { |
232 | return -EINVAL; | |
233 | } | |
234 | ||
235 | static int devfreq_register_opp_notifier(struct device *dev, | |
236 | struct devfreq *devfreq) | |
237 | { | |
238 | return -EINVAL; | |
239 | } | |
240 | ||
241 | static int devfreq_unregister_opp_notifier(struct device *dev, | |
242 | struct devfreq *devfreq) | |
243 | { | |
244 | return -EINVAL; | |
245 | } | |
246 | ||
ce26c5bb MH |
247 | #define devfreq_powersave NULL |
248 | #define devfreq_performance NULL | |
249 | #define devfreq_userspace NULL | |
250 | #define devfreq_simple_ondemand NULL | |
251 | ||
a3c98b8b MH |
252 | #endif /* CONFIG_PM_DEVFREQ */ |
253 | ||
254 | #endif /* __LINUX_DEVFREQ_H__ */ |