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 * @get_target_freq: Returns desired operating frequency for the device. 108 * Basically, get_target_freq will run 109 * devfreq_dev_profile.get_dev_status() to get the 110 * status of the device (load = busy_time / total_time). 111 * If no_central_polling is set, this callback is called 112 * only with update_devfreq() notified by OPP. 113 * @event_handler: Callback for devfreq core framework to notify events 114 * to governors. Events include per device governor 115 * init and exit, opp changes out of devfreq, suspend 116 * and resume of per device devfreq during device idle. 117 * 118 * Note that the callbacks are called with devfreq->lock locked by devfreq. 119 */ 120 struct devfreq_governor { 121 struct list_head node; 122 123 const char name[DEVFREQ_NAME_LEN]; 124 int (*get_target_freq)(struct devfreq *this, unsigned long *freq); 125 int (*event_handler)(struct devfreq *devfreq, 126 unsigned int event, void *data); 127 }; 128 129 /** 130 * struct devfreq - Device devfreq structure 131 * @node: list node - contains the devices with devfreq that have been 132 * registered. 133 * @lock: a mutex to protect accessing devfreq. 134 * @dev: device registered by devfreq class. dev.parent is the device 135 * using devfreq. 136 * @profile: device-specific devfreq profile 137 * @governor: method how to choose frequency based on the usage. 138 * @governor_name: devfreq governor name for use with this devfreq 139 * @nb: notifier block used to notify devfreq object that it should 140 * reevaluate operable frequencies. Devfreq users may use 141 * devfreq.nb to the corresponding register notifier call chain. 142 * @work: delayed work for load monitoring. 143 * @previous_freq: previously configured frequency value. 144 * @data: Private data of the governor. The devfreq framework does not 145 * touch this. 146 * @min_freq: Limit minimum frequency requested by user (0: none) 147 * @max_freq: Limit maximum frequency requested by user (0: none) 148 * @stop_polling: devfreq polling status of a device. 149 * @total_trans: Number of devfreq transitions 150 * @trans_table: Statistics of devfreq transitions 151 * @time_in_state: Statistics of devfreq states 152 * @last_stat_updated: The last time stat updated 153 * @transition_notifier_list: list head of DEVFREQ_TRANSITION_NOTIFIER notifier 154 * 155 * This structure stores the devfreq information for a give device. 156 * 157 * Note that when a governor accesses entries in struct devfreq in its 158 * functions except for the context of callbacks defined in struct 159 * devfreq_governor, the governor should protect its access with the 160 * struct mutex lock in struct devfreq. A governor may use this mutex 161 * to protect its own private data in void *data as well. 162 */ 163 struct devfreq { 164 struct list_head node; 165 166 struct mutex lock; 167 struct device dev; 168 struct devfreq_dev_profile *profile; 169 const struct devfreq_governor *governor; 170 char governor_name[DEVFREQ_NAME_LEN]; 171 struct notifier_block nb; 172 struct delayed_work work; 173 174 unsigned long previous_freq; 175 struct devfreq_dev_status last_status; 176 177 void *data; /* private data for governors */ 178 179 unsigned long min_freq; 180 unsigned long max_freq; 181 bool stop_polling; 182 183 /* information for device frequency transition */ 184 unsigned int total_trans; 185 unsigned int *trans_table; 186 unsigned long *time_in_state; 187 unsigned long last_stat_updated; 188 189 struct srcu_notifier_head transition_notifier_list; 190 }; 191 192 struct devfreq_freqs { 193 unsigned long old; 194 unsigned long new; 195 }; 196 197 #if defined(CONFIG_PM_DEVFREQ) 198 extern struct devfreq *devfreq_add_device(struct device *dev, 199 struct devfreq_dev_profile *profile, 200 const char *governor_name, 201 void *data); 202 extern int devfreq_remove_device(struct devfreq *devfreq); 203 extern struct devfreq *devm_devfreq_add_device(struct device *dev, 204 struct devfreq_dev_profile *profile, 205 const char *governor_name, 206 void *data); 207 extern void devm_devfreq_remove_device(struct device *dev, 208 struct devfreq *devfreq); 209 210 /* Supposed to be called by PM callbacks */ 211 extern int devfreq_suspend_device(struct devfreq *devfreq); 212 extern int devfreq_resume_device(struct devfreq *devfreq); 213 214 /* Helper functions for devfreq user device driver with OPP. */ 215 extern struct dev_pm_opp *devfreq_recommended_opp(struct device *dev, 216 unsigned long *freq, u32 flags); 217 extern int devfreq_register_opp_notifier(struct device *dev, 218 struct devfreq *devfreq); 219 extern int devfreq_unregister_opp_notifier(struct device *dev, 220 struct devfreq *devfreq); 221 extern int devm_devfreq_register_opp_notifier(struct device *dev, 222 struct devfreq *devfreq); 223 extern void devm_devfreq_unregister_opp_notifier(struct device *dev, 224 struct devfreq *devfreq); 225 extern int devfreq_register_notifier(struct devfreq *devfreq, 226 struct notifier_block *nb, 227 unsigned int list); 228 extern int devfreq_unregister_notifier(struct devfreq *devfreq, 229 struct notifier_block *nb, 230 unsigned int list); 231 extern int devm_devfreq_register_notifier(struct device *dev, 232 struct devfreq *devfreq, 233 struct notifier_block *nb, 234 unsigned int list); 235 extern void devm_devfreq_unregister_notifier(struct device *dev, 236 struct devfreq *devfreq, 237 struct notifier_block *nb, 238 unsigned int list); 239 extern struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev, 240 int index); 241 242 /** 243 * devfreq_update_stats() - update the last_status pointer in struct devfreq 244 * @df: the devfreq instance whose status needs updating 245 * 246 * Governors are recommended to use this function along with last_status, 247 * which allows other entities to reuse the last_status without affecting 248 * the values fetched later by governors. 249 */ 250 static inline int devfreq_update_stats(struct devfreq *df) 251 { 252 return df->profile->get_dev_status(df->dev.parent, &df->last_status); 253 } 254 255 #if IS_ENABLED(CONFIG_DEVFREQ_GOV_SIMPLE_ONDEMAND) 256 /** 257 * struct devfreq_simple_ondemand_data - void *data fed to struct devfreq 258 * and devfreq_add_device 259 * @upthreshold: If the load is over this value, the frequency jumps. 260 * Specify 0 to use the default. Valid value = 0 to 100. 261 * @downdifferential: If the load is under upthreshold - downdifferential, 262 * the governor may consider slowing the frequency down. 263 * Specify 0 to use the default. Valid value = 0 to 100. 264 * downdifferential < upthreshold must hold. 265 * 266 * If the fed devfreq_simple_ondemand_data pointer is NULL to the governor, 267 * the governor uses the default values. 268 */ 269 struct devfreq_simple_ondemand_data { 270 unsigned int upthreshold; 271 unsigned int downdifferential; 272 }; 273 #endif 274 275 #if IS_ENABLED(CONFIG_DEVFREQ_GOV_PASSIVE) 276 /** 277 * struct devfreq_passive_data - void *data fed to struct devfreq 278 * and devfreq_add_device 279 * @parent: the devfreq instance of parent device. 280 * @get_target_freq: Optional callback, Returns desired operating frequency 281 * for the device using passive governor. That is called 282 * when passive governor should decide the next frequency 283 * by using the new frequency of parent devfreq device 284 * using governors except for passive governor. 285 * If the devfreq device has the specific method to decide 286 * the next frequency, should use this callback. 287 * @this: the devfreq instance of own device. 288 * @nb: the notifier block for DEVFREQ_TRANSITION_NOTIFIER list 289 * 290 * The devfreq_passive_data have to set the devfreq instance of parent 291 * device with governors except for the passive governor. But, don't need to 292 * initialize the 'this' and 'nb' field because the devfreq core will handle 293 * them. 294 */ 295 struct devfreq_passive_data { 296 /* Should set the devfreq instance of parent device */ 297 struct devfreq *parent; 298 299 /* Optional callback to decide the next frequency of passvice device */ 300 int (*get_target_freq)(struct devfreq *this, unsigned long *freq); 301 302 /* For passive governor's internal use. Don't need to set them */ 303 struct devfreq *this; 304 struct notifier_block nb; 305 }; 306 #endif 307 308 #else /* !CONFIG_PM_DEVFREQ */ 309 static inline struct devfreq *devfreq_add_device(struct device *dev, 310 struct devfreq_dev_profile *profile, 311 const char *governor_name, 312 void *data) 313 { 314 return ERR_PTR(-ENOSYS); 315 } 316 317 static inline int devfreq_remove_device(struct devfreq *devfreq) 318 { 319 return 0; 320 } 321 322 static inline struct devfreq *devm_devfreq_add_device(struct device *dev, 323 struct devfreq_dev_profile *profile, 324 const char *governor_name, 325 void *data) 326 { 327 return ERR_PTR(-ENOSYS); 328 } 329 330 static inline void devm_devfreq_remove_device(struct device *dev, 331 struct devfreq *devfreq) 332 { 333 } 334 335 static inline int devfreq_suspend_device(struct devfreq *devfreq) 336 { 337 return 0; 338 } 339 340 static inline int devfreq_resume_device(struct devfreq *devfreq) 341 { 342 return 0; 343 } 344 345 static inline struct dev_pm_opp *devfreq_recommended_opp(struct device *dev, 346 unsigned long *freq, u32 flags) 347 { 348 return ERR_PTR(-EINVAL); 349 } 350 351 static inline int devfreq_register_opp_notifier(struct device *dev, 352 struct devfreq *devfreq) 353 { 354 return -EINVAL; 355 } 356 357 static inline int devfreq_unregister_opp_notifier(struct device *dev, 358 struct devfreq *devfreq) 359 { 360 return -EINVAL; 361 } 362 363 static inline int devm_devfreq_register_opp_notifier(struct device *dev, 364 struct devfreq *devfreq) 365 { 366 return -EINVAL; 367 } 368 369 static inline void devm_devfreq_unregister_opp_notifier(struct device *dev, 370 struct devfreq *devfreq) 371 { 372 } 373 374 static inline int devfreq_register_notifier(struct devfreq *devfreq, 375 struct notifier_block *nb, 376 unsigned int list) 377 { 378 return 0; 379 } 380 381 static inline int devfreq_unregister_notifier(struct devfreq *devfreq, 382 struct notifier_block *nb, 383 unsigned int list) 384 { 385 return 0; 386 } 387 388 static inline int devm_devfreq_register_notifier(struct device *dev, 389 struct devfreq *devfreq, 390 struct notifier_block *nb, 391 unsigned int list) 392 { 393 return 0; 394 } 395 396 static inline void devm_devfreq_unregister_notifier(struct device *dev, 397 struct devfreq *devfreq, 398 struct notifier_block *nb, 399 unsigned int list) 400 { 401 } 402 403 static inline struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev, 404 int index) 405 { 406 return ERR_PTR(-ENODEV); 407 } 408 409 static inline int devfreq_update_stats(struct devfreq *df) 410 { 411 return -EINVAL; 412 } 413 #endif /* CONFIG_PM_DEVFREQ */ 414 415 #endif /* __LINUX_DEVFREQ_H__ */ 416