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/pm_opp.h> 19 20 #define DEVFREQ_NAME_LEN 16 21 22 /* DEVFREQ notifier interface */ 23 #define DEVFREQ_TRANSITION_NOTIFIER (0) 24 25 /* Transition notifiers of DEVFREQ_TRANSITION_NOTIFIER */ 26 #define DEVFREQ_PRECHANGE (0) 27 #define DEVFREQ_POSTCHANGE (1) 28 29 struct devfreq; 30 31 /** 32 * struct devfreq_dev_status - Data given from devfreq user device to 33 * governors. Represents the performance 34 * statistics. 35 * @total_time: The total time represented by this instance of 36 * devfreq_dev_status 37 * @busy_time: The time that the device was working among the 38 * total_time. 39 * @current_frequency: The operating frequency. 40 * @private_data: An entry not specified by the devfreq framework. 41 * A device and a specific governor may have their 42 * own protocol with private_data. However, because 43 * this is governor-specific, a governor using this 44 * will be only compatible with devices aware of it. 45 */ 46 struct devfreq_dev_status { 47 /* both since the last measure */ 48 unsigned long total_time; 49 unsigned long busy_time; 50 unsigned long current_frequency; 51 void *private_data; 52 }; 53 54 /* 55 * The resulting frequency should be at most this. (this bound is the 56 * least upper bound; thus, the resulting freq should be lower or same) 57 * If the flag is not set, the resulting frequency should be at most the 58 * bound (greatest lower bound) 59 */ 60 #define DEVFREQ_FLAG_LEAST_UPPER_BOUND 0x1 61 62 /** 63 * struct devfreq_dev_profile - Devfreq's user device profile 64 * @initial_freq: The operating frequency when devfreq_add_device() is 65 * called. 66 * @polling_ms: The polling interval in ms. 0 disables polling. 67 * @target: The device should set its operating frequency at 68 * freq or lowest-upper-than-freq value. If freq is 69 * higher than any operable frequency, set maximum. 70 * Before returning, target function should set 71 * freq at the current frequency. 72 * The "flags" parameter's possible values are 73 * explained above with "DEVFREQ_FLAG_*" macros. 74 * @get_dev_status: The device should provide the current performance 75 * status to devfreq. Governors are recommended not to 76 * use this directly. Instead, governors are recommended 77 * to use devfreq_update_stats() along with 78 * devfreq.last_status. 79 * @get_cur_freq: The device should provide the current frequency 80 * at which it is operating. 81 * @exit: An optional callback that is called when devfreq 82 * is removing the devfreq object due to error or 83 * from devfreq_remove_device() call. If the user 84 * has registered devfreq->nb at a notifier-head, 85 * this is the time to unregister it. 86 * @freq_table: Optional list of frequencies to support statistics. 87 * @max_state: The size of freq_table. 88 */ 89 struct devfreq_dev_profile { 90 unsigned long initial_freq; 91 unsigned int polling_ms; 92 93 int (*target)(struct device *dev, unsigned long *freq, u32 flags); 94 int (*get_dev_status)(struct device *dev, 95 struct devfreq_dev_status *stat); 96 int (*get_cur_freq)(struct device *dev, unsigned long *freq); 97 void (*exit)(struct device *dev); 98 99 unsigned long *freq_table; 100 unsigned int max_state; 101 }; 102 103 /** 104 * struct devfreq_governor - Devfreq policy governor 105 * @node: list node - contains registered devfreq governors 106 * @name: Governor's name 107 * @immutable: Immutable flag for governor. If the value is 1, 108 * this govenror is never changeable to other governor. 109 * @get_target_freq: Returns desired operating frequency for the device. 110 * Basically, get_target_freq will run 111 * devfreq_dev_profile.get_dev_status() to get the 112 * status of the device (load = busy_time / total_time). 113 * If no_central_polling is set, this callback is called 114 * only with update_devfreq() notified by OPP. 115 * @event_handler: Callback for devfreq core framework to notify events 116 * to governors. Events include per device governor 117 * init and exit, opp changes out of devfreq, suspend 118 * and resume of per device devfreq during device idle. 119 * 120 * Note that the callbacks are called with devfreq->lock locked by devfreq. 121 */ 122 struct devfreq_governor { 123 struct list_head node; 124 125 const char name[DEVFREQ_NAME_LEN]; 126 const unsigned int immutable; 127 int (*get_target_freq)(struct devfreq *this, unsigned long *freq); 128 int (*event_handler)(struct devfreq *devfreq, 129 unsigned int event, void *data); 130 }; 131 132 /** 133 * struct devfreq - Device devfreq structure 134 * @node: list node - contains the devices with devfreq that have been 135 * registered. 136 * @lock: a mutex to protect accessing devfreq. 137 * @dev: device registered by devfreq class. dev.parent is the device 138 * using devfreq. 139 * @profile: device-specific devfreq profile 140 * @governor: method how to choose frequency based on the usage. 141 * @governor_name: devfreq governor name for use with this devfreq 142 * @nb: notifier block used to notify devfreq object that it should 143 * reevaluate operable frequencies. Devfreq users may use 144 * devfreq.nb to the corresponding register notifier call chain. 145 * @work: delayed work for load monitoring. 146 * @previous_freq: previously configured frequency value. 147 * @data: Private data of the governor. The devfreq framework does not 148 * touch this. 149 * @min_freq: Limit minimum frequency requested by user (0: none) 150 * @max_freq: Limit maximum frequency requested by user (0: none) 151 * @stop_polling: devfreq polling status of a device. 152 * @total_trans: Number of devfreq transitions 153 * @trans_table: Statistics of devfreq transitions 154 * @time_in_state: Statistics of devfreq states 155 * @last_stat_updated: The last time stat updated 156 * @transition_notifier_list: list head of DEVFREQ_TRANSITION_NOTIFIER notifier 157 * 158 * This structure stores the devfreq information for a give device. 159 * 160 * Note that when a governor accesses entries in struct devfreq in its 161 * functions except for the context of callbacks defined in struct 162 * devfreq_governor, the governor should protect its access with the 163 * struct mutex lock in struct devfreq. A governor may use this mutex 164 * to protect its own private data in void *data as well. 165 */ 166 struct devfreq { 167 struct list_head node; 168 169 struct mutex lock; 170 struct device dev; 171 struct devfreq_dev_profile *profile; 172 const struct devfreq_governor *governor; 173 char governor_name[DEVFREQ_NAME_LEN]; 174 struct notifier_block nb; 175 struct delayed_work work; 176 177 unsigned long previous_freq; 178 struct devfreq_dev_status last_status; 179 180 void *data; /* private data for governors */ 181 182 unsigned long min_freq; 183 unsigned long max_freq; 184 bool stop_polling; 185 186 /* information for device frequency transition */ 187 unsigned int total_trans; 188 unsigned int *trans_table; 189 unsigned long *time_in_state; 190 unsigned long last_stat_updated; 191 192 struct srcu_notifier_head transition_notifier_list; 193 }; 194 195 struct devfreq_freqs { 196 unsigned long old; 197 unsigned long new; 198 }; 199 200 #if defined(CONFIG_PM_DEVFREQ) 201 extern struct devfreq *devfreq_add_device(struct device *dev, 202 struct devfreq_dev_profile *profile, 203 const char *governor_name, 204 void *data); 205 extern int devfreq_remove_device(struct devfreq *devfreq); 206 extern struct devfreq *devm_devfreq_add_device(struct device *dev, 207 struct devfreq_dev_profile *profile, 208 const char *governor_name, 209 void *data); 210 extern void devm_devfreq_remove_device(struct device *dev, 211 struct devfreq *devfreq); 212 213 /* Supposed to be called by PM callbacks */ 214 extern int devfreq_suspend_device(struct devfreq *devfreq); 215 extern int devfreq_resume_device(struct devfreq *devfreq); 216 217 /* Helper functions for devfreq user device driver with OPP. */ 218 extern struct dev_pm_opp *devfreq_recommended_opp(struct device *dev, 219 unsigned long *freq, u32 flags); 220 extern int devfreq_register_opp_notifier(struct device *dev, 221 struct devfreq *devfreq); 222 extern int devfreq_unregister_opp_notifier(struct device *dev, 223 struct devfreq *devfreq); 224 extern int devm_devfreq_register_opp_notifier(struct device *dev, 225 struct devfreq *devfreq); 226 extern void devm_devfreq_unregister_opp_notifier(struct device *dev, 227 struct devfreq *devfreq); 228 extern int devfreq_register_notifier(struct devfreq *devfreq, 229 struct notifier_block *nb, 230 unsigned int list); 231 extern int devfreq_unregister_notifier(struct devfreq *devfreq, 232 struct notifier_block *nb, 233 unsigned int list); 234 extern int devm_devfreq_register_notifier(struct device *dev, 235 struct devfreq *devfreq, 236 struct notifier_block *nb, 237 unsigned int list); 238 extern void devm_devfreq_unregister_notifier(struct device *dev, 239 struct devfreq *devfreq, 240 struct notifier_block *nb, 241 unsigned int list); 242 extern struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev, 243 int index); 244 245 /** 246 * devfreq_update_stats() - update the last_status pointer in struct devfreq 247 * @df: the devfreq instance whose status needs updating 248 * 249 * Governors are recommended to use this function along with last_status, 250 * which allows other entities to reuse the last_status without affecting 251 * the values fetched later by governors. 252 */ 253 static inline int devfreq_update_stats(struct devfreq *df) 254 { 255 return df->profile->get_dev_status(df->dev.parent, &df->last_status); 256 } 257 258 #if IS_ENABLED(CONFIG_DEVFREQ_GOV_SIMPLE_ONDEMAND) 259 /** 260 * struct devfreq_simple_ondemand_data - void *data fed to struct devfreq 261 * and devfreq_add_device 262 * @upthreshold: If the load is over this value, the frequency jumps. 263 * Specify 0 to use the default. Valid value = 0 to 100. 264 * @downdifferential: If the load is under upthreshold - downdifferential, 265 * the governor may consider slowing the frequency down. 266 * Specify 0 to use the default. Valid value = 0 to 100. 267 * downdifferential < upthreshold must hold. 268 * 269 * If the fed devfreq_simple_ondemand_data pointer is NULL to the governor, 270 * the governor uses the default values. 271 */ 272 struct devfreq_simple_ondemand_data { 273 unsigned int upthreshold; 274 unsigned int downdifferential; 275 }; 276 #endif 277 278 #if IS_ENABLED(CONFIG_DEVFREQ_GOV_PASSIVE) 279 /** 280 * struct devfreq_passive_data - void *data fed to struct devfreq 281 * and devfreq_add_device 282 * @parent: the devfreq instance of parent device. 283 * @get_target_freq: Optional callback, Returns desired operating frequency 284 * for the device using passive governor. That is called 285 * when passive governor should decide the next frequency 286 * by using the new frequency of parent devfreq device 287 * using governors except for passive governor. 288 * If the devfreq device has the specific method to decide 289 * the next frequency, should use this callback. 290 * @this: the devfreq instance of own device. 291 * @nb: the notifier block for DEVFREQ_TRANSITION_NOTIFIER list 292 * 293 * The devfreq_passive_data have to set the devfreq instance of parent 294 * device with governors except for the passive governor. But, don't need to 295 * initialize the 'this' and 'nb' field because the devfreq core will handle 296 * them. 297 */ 298 struct devfreq_passive_data { 299 /* Should set the devfreq instance of parent device */ 300 struct devfreq *parent; 301 302 /* Optional callback to decide the next frequency of passvice device */ 303 int (*get_target_freq)(struct devfreq *this, unsigned long *freq); 304 305 /* For passive governor's internal use. Don't need to set them */ 306 struct devfreq *this; 307 struct notifier_block nb; 308 }; 309 #endif 310 311 #else /* !CONFIG_PM_DEVFREQ */ 312 static inline struct devfreq *devfreq_add_device(struct device *dev, 313 struct devfreq_dev_profile *profile, 314 const char *governor_name, 315 void *data) 316 { 317 return ERR_PTR(-ENOSYS); 318 } 319 320 static inline int devfreq_remove_device(struct devfreq *devfreq) 321 { 322 return 0; 323 } 324 325 static inline struct devfreq *devm_devfreq_add_device(struct device *dev, 326 struct devfreq_dev_profile *profile, 327 const char *governor_name, 328 void *data) 329 { 330 return ERR_PTR(-ENOSYS); 331 } 332 333 static inline void devm_devfreq_remove_device(struct device *dev, 334 struct devfreq *devfreq) 335 { 336 } 337 338 static inline int devfreq_suspend_device(struct devfreq *devfreq) 339 { 340 return 0; 341 } 342 343 static inline int devfreq_resume_device(struct devfreq *devfreq) 344 { 345 return 0; 346 } 347 348 static inline struct dev_pm_opp *devfreq_recommended_opp(struct device *dev, 349 unsigned long *freq, u32 flags) 350 { 351 return ERR_PTR(-EINVAL); 352 } 353 354 static inline int devfreq_register_opp_notifier(struct device *dev, 355 struct devfreq *devfreq) 356 { 357 return -EINVAL; 358 } 359 360 static inline int devfreq_unregister_opp_notifier(struct device *dev, 361 struct devfreq *devfreq) 362 { 363 return -EINVAL; 364 } 365 366 static inline int devm_devfreq_register_opp_notifier(struct device *dev, 367 struct devfreq *devfreq) 368 { 369 return -EINVAL; 370 } 371 372 static inline void devm_devfreq_unregister_opp_notifier(struct device *dev, 373 struct devfreq *devfreq) 374 { 375 } 376 377 static inline int devfreq_register_notifier(struct devfreq *devfreq, 378 struct notifier_block *nb, 379 unsigned int list) 380 { 381 return 0; 382 } 383 384 static inline int devfreq_unregister_notifier(struct devfreq *devfreq, 385 struct notifier_block *nb, 386 unsigned int list) 387 { 388 return 0; 389 } 390 391 static inline int devm_devfreq_register_notifier(struct device *dev, 392 struct devfreq *devfreq, 393 struct notifier_block *nb, 394 unsigned int list) 395 { 396 return 0; 397 } 398 399 static inline void devm_devfreq_unregister_notifier(struct device *dev, 400 struct devfreq *devfreq, 401 struct notifier_block *nb, 402 unsigned int list) 403 { 404 } 405 406 static inline struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev, 407 int index) 408 { 409 return ERR_PTR(-ENODEV); 410 } 411 412 static inline int devfreq_update_stats(struct devfreq *df) 413 { 414 return -EINVAL; 415 } 416 #endif /* CONFIG_PM_DEVFREQ */ 417 418 #endif /* __LINUX_DEVFREQ_H__ */ 419