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