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 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 extern void devfreq_suspend(void); 209 extern void devfreq_resume(void); 210 211 /** 212 * update_devfreq() - Reevaluate the device and configure frequency 213 * @devfreq: the devfreq device 214 * 215 * Note: devfreq->lock must be held 216 */ 217 extern int update_devfreq(struct devfreq *devfreq); 218 219 /* Helper functions for devfreq user device driver with OPP. */ 220 extern struct dev_pm_opp *devfreq_recommended_opp(struct device *dev, 221 unsigned long *freq, u32 flags); 222 extern int devfreq_register_opp_notifier(struct device *dev, 223 struct devfreq *devfreq); 224 extern int devfreq_unregister_opp_notifier(struct device *dev, 225 struct devfreq *devfreq); 226 extern int devm_devfreq_register_opp_notifier(struct device *dev, 227 struct devfreq *devfreq); 228 extern void devm_devfreq_unregister_opp_notifier(struct device *dev, 229 struct devfreq *devfreq); 230 extern int devfreq_register_notifier(struct devfreq *devfreq, 231 struct notifier_block *nb, 232 unsigned int list); 233 extern int devfreq_unregister_notifier(struct devfreq *devfreq, 234 struct notifier_block *nb, 235 unsigned int list); 236 extern int devm_devfreq_register_notifier(struct device *dev, 237 struct devfreq *devfreq, 238 struct notifier_block *nb, 239 unsigned int list); 240 extern void devm_devfreq_unregister_notifier(struct device *dev, 241 struct devfreq *devfreq, 242 struct notifier_block *nb, 243 unsigned int list); 244 extern struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev, 245 int index); 246 247 #if IS_ENABLED(CONFIG_DEVFREQ_GOV_SIMPLE_ONDEMAND) 248 /** 249 * struct devfreq_simple_ondemand_data - void *data fed to struct devfreq 250 * and devfreq_add_device 251 * @upthreshold: If the load is over this value, the frequency jumps. 252 * Specify 0 to use the default. Valid value = 0 to 100. 253 * @downdifferential: If the load is under upthreshold - downdifferential, 254 * the governor may consider slowing the frequency down. 255 * Specify 0 to use the default. Valid value = 0 to 100. 256 * downdifferential < upthreshold must hold. 257 * 258 * If the fed devfreq_simple_ondemand_data pointer is NULL to the governor, 259 * the governor uses the default values. 260 */ 261 struct devfreq_simple_ondemand_data { 262 unsigned int upthreshold; 263 unsigned int downdifferential; 264 }; 265 #endif 266 267 #if IS_ENABLED(CONFIG_DEVFREQ_GOV_PASSIVE) 268 /** 269 * struct devfreq_passive_data - void *data fed to struct devfreq 270 * and devfreq_add_device 271 * @parent: the devfreq instance of parent device. 272 * @get_target_freq: Optional callback, Returns desired operating frequency 273 * for the device using passive governor. That is called 274 * when passive governor should decide the next frequency 275 * by using the new frequency of parent devfreq device 276 * using governors except for passive governor. 277 * If the devfreq device has the specific method to decide 278 * the next frequency, should use this callback. 279 * @this: the devfreq instance of own device. 280 * @nb: the notifier block for DEVFREQ_TRANSITION_NOTIFIER list 281 * 282 * The devfreq_passive_data have to set the devfreq instance of parent 283 * device with governors except for the passive governor. But, don't need to 284 * initialize the 'this' and 'nb' field because the devfreq core will handle 285 * them. 286 */ 287 struct devfreq_passive_data { 288 /* Should set the devfreq instance of parent device */ 289 struct devfreq *parent; 290 291 /* Optional callback to decide the next frequency of passvice device */ 292 int (*get_target_freq)(struct devfreq *this, unsigned long *freq); 293 294 /* For passive governor's internal use. Don't need to set them */ 295 struct devfreq *this; 296 struct notifier_block nb; 297 }; 298 #endif 299 300 #else /* !CONFIG_PM_DEVFREQ */ 301 static inline struct devfreq *devfreq_add_device(struct device *dev, 302 struct devfreq_dev_profile *profile, 303 const char *governor_name, 304 void *data) 305 { 306 return ERR_PTR(-ENOSYS); 307 } 308 309 static inline int devfreq_remove_device(struct devfreq *devfreq) 310 { 311 return 0; 312 } 313 314 static inline struct devfreq *devm_devfreq_add_device(struct device *dev, 315 struct devfreq_dev_profile *profile, 316 const char *governor_name, 317 void *data) 318 { 319 return ERR_PTR(-ENOSYS); 320 } 321 322 static inline void devm_devfreq_remove_device(struct device *dev, 323 struct devfreq *devfreq) 324 { 325 } 326 327 static inline int devfreq_suspend_device(struct devfreq *devfreq) 328 { 329 return 0; 330 } 331 332 static inline int devfreq_resume_device(struct devfreq *devfreq) 333 { 334 return 0; 335 } 336 337 static inline void devfreq_suspend(void) {} 338 static inline void devfreq_resume(void) {} 339 340 static inline struct dev_pm_opp *devfreq_recommended_opp(struct device *dev, 341 unsigned long *freq, u32 flags) 342 { 343 return ERR_PTR(-EINVAL); 344 } 345 346 static inline int devfreq_register_opp_notifier(struct device *dev, 347 struct devfreq *devfreq) 348 { 349 return -EINVAL; 350 } 351 352 static inline int devfreq_unregister_opp_notifier(struct device *dev, 353 struct devfreq *devfreq) 354 { 355 return -EINVAL; 356 } 357 358 static inline int devm_devfreq_register_opp_notifier(struct device *dev, 359 struct devfreq *devfreq) 360 { 361 return -EINVAL; 362 } 363 364 static inline void devm_devfreq_unregister_opp_notifier(struct device *dev, 365 struct devfreq *devfreq) 366 { 367 } 368 369 static inline int devfreq_register_notifier(struct devfreq *devfreq, 370 struct notifier_block *nb, 371 unsigned int list) 372 { 373 return 0; 374 } 375 376 static inline int devfreq_unregister_notifier(struct devfreq *devfreq, 377 struct notifier_block *nb, 378 unsigned int list) 379 { 380 return 0; 381 } 382 383 static inline int devm_devfreq_register_notifier(struct device *dev, 384 struct devfreq *devfreq, 385 struct notifier_block *nb, 386 unsigned int list) 387 { 388 return 0; 389 } 390 391 static inline void devm_devfreq_unregister_notifier(struct device *dev, 392 struct devfreq *devfreq, 393 struct notifier_block *nb, 394 unsigned int list) 395 { 396 } 397 398 static inline struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev, 399 int index) 400 { 401 return ERR_PTR(-ENODEV); 402 } 403 404 static inline int devfreq_update_stats(struct devfreq *df) 405 { 406 return -EINVAL; 407 } 408 #endif /* CONFIG_PM_DEVFREQ */ 409 410 #endif /* __LINUX_DEVFREQ_H__ */ 411