1 /* SPDX-License-Identifier: GPL-2.0-only */ 2 /* 3 * devfreq: Generic Dynamic Voltage and Frequency Scaling (DVFS) Framework 4 * for Non-CPU Devices. 5 * 6 * Copyright (C) 2011 Samsung Electronics 7 * MyungJoo Ham <myungjoo.ham@samsung.com> 8 */ 9 10 #ifndef __LINUX_DEVFREQ_H__ 11 #define __LINUX_DEVFREQ_H__ 12 13 #include <linux/device.h> 14 #include <linux/notifier.h> 15 #include <linux/pm_opp.h> 16 17 #define DEVFREQ_NAME_LEN 16 18 19 /* DEVFREQ governor name */ 20 #define DEVFREQ_GOV_SIMPLE_ONDEMAND "simple_ondemand" 21 #define DEVFREQ_GOV_PERFORMANCE "performance" 22 #define DEVFREQ_GOV_POWERSAVE "powersave" 23 #define DEVFREQ_GOV_USERSPACE "userspace" 24 #define DEVFREQ_GOV_PASSIVE "passive" 25 26 /* DEVFREQ notifier interface */ 27 #define DEVFREQ_TRANSITION_NOTIFIER (0) 28 29 /* Transition notifiers of DEVFREQ_TRANSITION_NOTIFIER */ 30 #define DEVFREQ_PRECHANGE (0) 31 #define DEVFREQ_POSTCHANGE (1) 32 33 struct devfreq; 34 struct devfreq_governor; 35 36 /** 37 * struct devfreq_dev_status - Data given from devfreq user device to 38 * governors. Represents the performance 39 * statistics. 40 * @total_time: The total time represented by this instance of 41 * devfreq_dev_status 42 * @busy_time: The time that the device was working among the 43 * total_time. 44 * @current_frequency: The operating frequency. 45 * @private_data: An entry not specified by the devfreq framework. 46 * A device and a specific governor may have their 47 * own protocol with private_data. However, because 48 * this is governor-specific, a governor using this 49 * will be only compatible with devices aware of it. 50 */ 51 struct devfreq_dev_status { 52 /* both since the last measure */ 53 unsigned long total_time; 54 unsigned long busy_time; 55 unsigned long current_frequency; 56 void *private_data; 57 }; 58 59 /* 60 * The resulting frequency should be at most this. (this bound is the 61 * least upper bound; thus, the resulting freq should be lower or same) 62 * If the flag is not set, the resulting frequency should be at most the 63 * bound (greatest lower bound) 64 */ 65 #define DEVFREQ_FLAG_LEAST_UPPER_BOUND 0x1 66 67 /** 68 * struct devfreq_dev_profile - Devfreq's user device profile 69 * @initial_freq: The operating frequency when devfreq_add_device() is 70 * called. 71 * @polling_ms: The polling interval in ms. 0 disables polling. 72 * @target: The device should set its operating frequency at 73 * freq or lowest-upper-than-freq value. If freq is 74 * higher than any operable frequency, set maximum. 75 * Before returning, target function should set 76 * freq at the current frequency. 77 * The "flags" parameter's possible values are 78 * explained above with "DEVFREQ_FLAG_*" macros. 79 * @get_dev_status: The device should provide the current performance 80 * status to devfreq. Governors are recommended not to 81 * use this directly. Instead, governors are recommended 82 * to use devfreq_update_stats() along with 83 * devfreq.last_status. 84 * @get_cur_freq: The device should provide the current frequency 85 * at which it is operating. 86 * @exit: An optional callback that is called when devfreq 87 * is removing the devfreq object due to error or 88 * from devfreq_remove_device() call. If the user 89 * has registered devfreq->nb at a notifier-head, 90 * this is the time to unregister it. 91 * @freq_table: Optional list of frequencies to support statistics 92 * and freq_table must be generated in ascending order. 93 * @max_state: The size of freq_table. 94 */ 95 struct devfreq_dev_profile { 96 unsigned long initial_freq; 97 unsigned int polling_ms; 98 99 int (*target)(struct device *dev, unsigned long *freq, u32 flags); 100 int (*get_dev_status)(struct device *dev, 101 struct devfreq_dev_status *stat); 102 int (*get_cur_freq)(struct device *dev, unsigned long *freq); 103 void (*exit)(struct device *dev); 104 105 unsigned long *freq_table; 106 unsigned int max_state; 107 }; 108 109 /** 110 * struct devfreq - Device devfreq structure 111 * @node: list node - contains the devices with devfreq that have been 112 * registered. 113 * @lock: a mutex to protect accessing devfreq. 114 * @dev: device registered by devfreq class. dev.parent is the device 115 * using devfreq. 116 * @profile: device-specific devfreq profile 117 * @governor: method how to choose frequency based on the usage. 118 * @governor_name: devfreq governor name for use with this devfreq 119 * @nb: notifier block used to notify devfreq object that it should 120 * reevaluate operable frequencies. Devfreq users may use 121 * devfreq.nb to the corresponding register notifier call chain. 122 * @work: delayed work for load monitoring. 123 * @previous_freq: previously configured frequency value. 124 * @data: Private data of the governor. The devfreq framework does not 125 * touch this. 126 * @min_freq: Limit minimum frequency requested by user (0: none) 127 * @max_freq: Limit maximum frequency requested by user (0: none) 128 * @scaling_min_freq: Limit minimum frequency requested by OPP interface 129 * @scaling_max_freq: Limit maximum frequency requested by OPP interface 130 * @stop_polling: devfreq polling status of a device. 131 * @suspend_freq: frequency of a device set during suspend phase. 132 * @resume_freq: frequency of a device set in resume phase. 133 * @suspend_count: suspend requests counter for a device. 134 * @total_trans: Number of devfreq transitions 135 * @trans_table: Statistics of devfreq transitions 136 * @time_in_state: Statistics of devfreq states 137 * @last_stat_updated: The last time stat updated 138 * @transition_notifier_list: list head of DEVFREQ_TRANSITION_NOTIFIER notifier 139 * 140 * This structure stores the devfreq information for a give device. 141 * 142 * Note that when a governor accesses entries in struct devfreq in its 143 * functions except for the context of callbacks defined in struct 144 * devfreq_governor, the governor should protect its access with the 145 * struct mutex lock in struct devfreq. A governor may use this mutex 146 * to protect its own private data in void *data as well. 147 */ 148 struct devfreq { 149 struct list_head node; 150 151 struct mutex lock; 152 struct device dev; 153 struct devfreq_dev_profile *profile; 154 const struct devfreq_governor *governor; 155 char governor_name[DEVFREQ_NAME_LEN]; 156 struct notifier_block nb; 157 struct delayed_work work; 158 159 unsigned long previous_freq; 160 struct devfreq_dev_status last_status; 161 162 void *data; /* private data for governors */ 163 164 unsigned long min_freq; 165 unsigned long max_freq; 166 unsigned long scaling_min_freq; 167 unsigned long scaling_max_freq; 168 bool stop_polling; 169 170 unsigned long suspend_freq; 171 unsigned long resume_freq; 172 atomic_t suspend_count; 173 174 /* information for device frequency transition */ 175 unsigned int total_trans; 176 unsigned int *trans_table; 177 unsigned long *time_in_state; 178 unsigned long last_stat_updated; 179 180 struct srcu_notifier_head transition_notifier_list; 181 }; 182 183 struct devfreq_freqs { 184 unsigned long old; 185 unsigned long new; 186 }; 187 188 #if defined(CONFIG_PM_DEVFREQ) 189 extern struct devfreq *devfreq_add_device(struct device *dev, 190 struct devfreq_dev_profile *profile, 191 const char *governor_name, 192 void *data); 193 extern int devfreq_remove_device(struct devfreq *devfreq); 194 extern struct devfreq *devm_devfreq_add_device(struct device *dev, 195 struct devfreq_dev_profile *profile, 196 const char *governor_name, 197 void *data); 198 extern void devm_devfreq_remove_device(struct device *dev, 199 struct devfreq *devfreq); 200 201 /* Supposed to be called by PM callbacks */ 202 extern int devfreq_suspend_device(struct devfreq *devfreq); 203 extern int devfreq_resume_device(struct devfreq *devfreq); 204 205 extern void devfreq_suspend(void); 206 extern void devfreq_resume(void); 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 void devfreq_suspend(void) {} 335 static inline void devfreq_resume(void) {} 336 337 static inline struct dev_pm_opp *devfreq_recommended_opp(struct device *dev, 338 unsigned long *freq, u32 flags) 339 { 340 return ERR_PTR(-EINVAL); 341 } 342 343 static inline int devfreq_register_opp_notifier(struct device *dev, 344 struct devfreq *devfreq) 345 { 346 return -EINVAL; 347 } 348 349 static inline int devfreq_unregister_opp_notifier(struct device *dev, 350 struct devfreq *devfreq) 351 { 352 return -EINVAL; 353 } 354 355 static inline int devm_devfreq_register_opp_notifier(struct device *dev, 356 struct devfreq *devfreq) 357 { 358 return -EINVAL; 359 } 360 361 static inline void devm_devfreq_unregister_opp_notifier(struct device *dev, 362 struct devfreq *devfreq) 363 { 364 } 365 366 static inline int devfreq_register_notifier(struct devfreq *devfreq, 367 struct notifier_block *nb, 368 unsigned int list) 369 { 370 return 0; 371 } 372 373 static inline int devfreq_unregister_notifier(struct devfreq *devfreq, 374 struct notifier_block *nb, 375 unsigned int list) 376 { 377 return 0; 378 } 379 380 static inline int devm_devfreq_register_notifier(struct device *dev, 381 struct devfreq *devfreq, 382 struct notifier_block *nb, 383 unsigned int list) 384 { 385 return 0; 386 } 387 388 static inline void devm_devfreq_unregister_notifier(struct device *dev, 389 struct devfreq *devfreq, 390 struct notifier_block *nb, 391 unsigned int list) 392 { 393 } 394 395 static inline struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev, 396 int index) 397 { 398 return ERR_PTR(-ENODEV); 399 } 400 401 static inline int devfreq_update_stats(struct devfreq *df) 402 { 403 return -EINVAL; 404 } 405 #endif /* CONFIG_PM_DEVFREQ */ 406 407 #endif /* __LINUX_DEVFREQ_H__ */ 408