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 #include <linux/pm_qos.h> 17 18 #define DEVFREQ_NAME_LEN 16 19 20 /* DEVFREQ governor name */ 21 #define DEVFREQ_GOV_SIMPLE_ONDEMAND "simple_ondemand" 22 #define DEVFREQ_GOV_PERFORMANCE "performance" 23 #define DEVFREQ_GOV_POWERSAVE "powersave" 24 #define DEVFREQ_GOV_USERSPACE "userspace" 25 #define DEVFREQ_GOV_PASSIVE "passive" 26 27 /* DEVFREQ notifier interface */ 28 #define DEVFREQ_TRANSITION_NOTIFIER (0) 29 30 /* Transition notifiers of DEVFREQ_TRANSITION_NOTIFIER */ 31 #define DEVFREQ_PRECHANGE (0) 32 #define DEVFREQ_POSTCHANGE (1) 33 34 /* DEVFREQ work timers */ 35 enum devfreq_timer { 36 DEVFREQ_TIMER_DEFERRABLE = 0, 37 DEVFREQ_TIMER_DELAYED, 38 DEVFREQ_TIMER_NUM, 39 }; 40 41 struct devfreq; 42 struct devfreq_governor; 43 44 /** 45 * struct devfreq_dev_status - Data given from devfreq user device to 46 * governors. Represents the performance 47 * statistics. 48 * @total_time: The total time represented by this instance of 49 * devfreq_dev_status 50 * @busy_time: The time that the device was working among the 51 * total_time. 52 * @current_frequency: The operating frequency. 53 * @private_data: An entry not specified by the devfreq framework. 54 * A device and a specific governor may have their 55 * own protocol with private_data. However, because 56 * this is governor-specific, a governor using this 57 * will be only compatible with devices aware of it. 58 */ 59 struct devfreq_dev_status { 60 /* both since the last measure */ 61 unsigned long total_time; 62 unsigned long busy_time; 63 unsigned long current_frequency; 64 void *private_data; 65 }; 66 67 /* 68 * The resulting frequency should be at most this. (this bound is the 69 * least upper bound; thus, the resulting freq should be lower or same) 70 * If the flag is not set, the resulting frequency should be at most the 71 * bound (greatest lower bound) 72 */ 73 #define DEVFREQ_FLAG_LEAST_UPPER_BOUND 0x1 74 75 /** 76 * struct devfreq_dev_profile - Devfreq's user device profile 77 * @initial_freq: The operating frequency when devfreq_add_device() is 78 * called. 79 * @polling_ms: The polling interval in ms. 0 disables polling. 80 * @timer: Timer type is either deferrable or delayed timer. 81 * @target: The device should set its operating frequency at 82 * freq or lowest-upper-than-freq value. If freq is 83 * higher than any operable frequency, set maximum. 84 * Before returning, target function should set 85 * freq at the current frequency. 86 * The "flags" parameter's possible values are 87 * explained above with "DEVFREQ_FLAG_*" macros. 88 * @get_dev_status: The device should provide the current performance 89 * status to devfreq. Governors are recommended not to 90 * use this directly. Instead, governors are recommended 91 * to use devfreq_update_stats() along with 92 * devfreq.last_status. 93 * @get_cur_freq: The device should provide the current frequency 94 * at which it is operating. 95 * @exit: An optional callback that is called when devfreq 96 * is removing the devfreq object due to error or 97 * from devfreq_remove_device() call. If the user 98 * has registered devfreq->nb at a notifier-head, 99 * this is the time to unregister it. 100 * @freq_table: Optional list of frequencies to support statistics 101 * and freq_table must be generated in ascending order. 102 * @max_state: The size of freq_table. 103 */ 104 struct devfreq_dev_profile { 105 unsigned long initial_freq; 106 unsigned int polling_ms; 107 enum devfreq_timer timer; 108 109 int (*target)(struct device *dev, unsigned long *freq, u32 flags); 110 int (*get_dev_status)(struct device *dev, 111 struct devfreq_dev_status *stat); 112 int (*get_cur_freq)(struct device *dev, unsigned long *freq); 113 void (*exit)(struct device *dev); 114 115 unsigned long *freq_table; 116 unsigned int max_state; 117 }; 118 119 /** 120 * struct devfreq_stats - Statistics of devfreq device behavior 121 * @total_trans: Number of devfreq transitions. 122 * @trans_table: Statistics of devfreq transitions. 123 * @time_in_state: Statistics of devfreq states. 124 * @last_update: The last time stats were updated. 125 */ 126 struct devfreq_stats { 127 unsigned int total_trans; 128 unsigned int *trans_table; 129 u64 *time_in_state; 130 u64 last_update; 131 }; 132 133 /** 134 * struct devfreq - Device devfreq structure 135 * @node: list node - contains the devices with devfreq that have been 136 * registered. 137 * @lock: a mutex to protect accessing devfreq. 138 * @dev: device registered by devfreq class. dev.parent is the device 139 * using devfreq. 140 * @profile: device-specific devfreq profile 141 * @governor: method how to choose frequency based on the usage. 142 * @governor_name: devfreq governor name for use with this devfreq 143 * @nb: notifier block used to notify devfreq object that it should 144 * reevaluate operable frequencies. Devfreq users may use 145 * devfreq.nb to the corresponding register notifier call chain. 146 * @work: delayed work for load monitoring. 147 * @previous_freq: previously configured frequency value. 148 * @last_status: devfreq user device info, performance statistics 149 * @data: Private data of the governor. The devfreq framework does not 150 * touch this. 151 * @user_min_freq_req: PM QoS minimum frequency request from user (via sysfs) 152 * @user_max_freq_req: PM QoS maximum frequency request from user (via sysfs) 153 * @scaling_min_freq: Limit minimum frequency requested by OPP interface 154 * @scaling_max_freq: Limit maximum frequency requested by OPP interface 155 * @stop_polling: devfreq polling status of a device. 156 * @suspend_freq: frequency of a device set during suspend phase. 157 * @resume_freq: frequency of a device set in resume phase. 158 * @suspend_count: suspend requests counter for a device. 159 * @stats: Statistics of devfreq device behavior 160 * @transition_notifier_list: list head of DEVFREQ_TRANSITION_NOTIFIER notifier 161 * @nb_min: Notifier block for DEV_PM_QOS_MIN_FREQUENCY 162 * @nb_max: Notifier block for DEV_PM_QOS_MAX_FREQUENCY 163 * 164 * This structure stores the devfreq information for a given device. 165 * 166 * Note that when a governor accesses entries in struct devfreq in its 167 * functions except for the context of callbacks defined in struct 168 * devfreq_governor, the governor should protect its access with the 169 * struct mutex lock in struct devfreq. A governor may use this mutex 170 * to protect its own private data in ``void *data`` as well. 171 */ 172 struct devfreq { 173 struct list_head node; 174 175 struct mutex lock; 176 struct device dev; 177 struct devfreq_dev_profile *profile; 178 const struct devfreq_governor *governor; 179 char governor_name[DEVFREQ_NAME_LEN]; 180 struct notifier_block nb; 181 struct delayed_work work; 182 183 unsigned long previous_freq; 184 struct devfreq_dev_status last_status; 185 186 void *data; /* private data for governors */ 187 188 struct dev_pm_qos_request user_min_freq_req; 189 struct dev_pm_qos_request user_max_freq_req; 190 unsigned long scaling_min_freq; 191 unsigned long scaling_max_freq; 192 bool stop_polling; 193 194 unsigned long suspend_freq; 195 unsigned long resume_freq; 196 atomic_t suspend_count; 197 198 /* information for device frequency transitions */ 199 struct devfreq_stats stats; 200 201 struct srcu_notifier_head transition_notifier_list; 202 203 struct notifier_block nb_min; 204 struct notifier_block nb_max; 205 }; 206 207 struct devfreq_freqs { 208 unsigned long old; 209 unsigned long new; 210 }; 211 212 #if defined(CONFIG_PM_DEVFREQ) 213 struct devfreq *devfreq_add_device(struct device *dev, 214 struct devfreq_dev_profile *profile, 215 const char *governor_name, 216 void *data); 217 int devfreq_remove_device(struct devfreq *devfreq); 218 struct devfreq *devm_devfreq_add_device(struct device *dev, 219 struct devfreq_dev_profile *profile, 220 const char *governor_name, 221 void *data); 222 void devm_devfreq_remove_device(struct device *dev, struct devfreq *devfreq); 223 224 /* Supposed to be called by PM callbacks */ 225 int devfreq_suspend_device(struct devfreq *devfreq); 226 int devfreq_resume_device(struct devfreq *devfreq); 227 228 void devfreq_suspend(void); 229 void devfreq_resume(void); 230 231 /** 232 * update_devfreq() - Reevaluate the device and configure frequency 233 * @devfreq: the devfreq device 234 * 235 * Note: devfreq->lock must be held 236 */ 237 int update_devfreq(struct devfreq *devfreq); 238 239 /* Helper functions for devfreq user device driver with OPP. */ 240 struct dev_pm_opp *devfreq_recommended_opp(struct device *dev, 241 unsigned long *freq, u32 flags); 242 int devfreq_register_opp_notifier(struct device *dev, 243 struct devfreq *devfreq); 244 int devfreq_unregister_opp_notifier(struct device *dev, 245 struct devfreq *devfreq); 246 int devm_devfreq_register_opp_notifier(struct device *dev, 247 struct devfreq *devfreq); 248 void devm_devfreq_unregister_opp_notifier(struct device *dev, 249 struct devfreq *devfreq); 250 int devfreq_register_notifier(struct devfreq *devfreq, 251 struct notifier_block *nb, 252 unsigned int list); 253 int devfreq_unregister_notifier(struct devfreq *devfreq, 254 struct notifier_block *nb, 255 unsigned int list); 256 int devm_devfreq_register_notifier(struct device *dev, 257 struct devfreq *devfreq, 258 struct notifier_block *nb, 259 unsigned int list); 260 void devm_devfreq_unregister_notifier(struct device *dev, 261 struct devfreq *devfreq, 262 struct notifier_block *nb, 263 unsigned int list); 264 struct devfreq *devfreq_get_devfreq_by_node(struct device_node *node); 265 struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev, 266 const char *phandle_name, int index); 267 268 #if IS_ENABLED(CONFIG_DEVFREQ_GOV_SIMPLE_ONDEMAND) 269 /** 270 * struct devfreq_simple_ondemand_data - ``void *data`` fed to struct devfreq 271 * and devfreq_add_device 272 * @upthreshold: If the load is over this value, the frequency jumps. 273 * Specify 0 to use the default. Valid value = 0 to 100. 274 * @downdifferential: If the load is under upthreshold - downdifferential, 275 * the governor may consider slowing the frequency down. 276 * Specify 0 to use the default. Valid value = 0 to 100. 277 * downdifferential < upthreshold must hold. 278 * 279 * If the fed devfreq_simple_ondemand_data pointer is NULL to the governor, 280 * the governor uses the default values. 281 */ 282 struct devfreq_simple_ondemand_data { 283 unsigned int upthreshold; 284 unsigned int downdifferential; 285 }; 286 #endif 287 288 #if IS_ENABLED(CONFIG_DEVFREQ_GOV_PASSIVE) 289 /** 290 * struct devfreq_passive_data - ``void *data`` fed to struct devfreq 291 * and devfreq_add_device 292 * @parent: the devfreq instance of parent device. 293 * @get_target_freq: Optional callback, Returns desired operating frequency 294 * for the device using passive governor. That is called 295 * when passive governor should decide the next frequency 296 * by using the new frequency of parent devfreq device 297 * using governors except for passive governor. 298 * If the devfreq device has the specific method to decide 299 * the next frequency, should use this callback. 300 * @this: the devfreq instance of own device. 301 * @nb: the notifier block for DEVFREQ_TRANSITION_NOTIFIER list 302 * 303 * The devfreq_passive_data have to set the devfreq instance of parent 304 * device with governors except for the passive governor. But, don't need to 305 * initialize the 'this' and 'nb' field because the devfreq core will handle 306 * them. 307 */ 308 struct devfreq_passive_data { 309 /* Should set the devfreq instance of parent device */ 310 struct devfreq *parent; 311 312 /* Optional callback to decide the next frequency of passvice device */ 313 int (*get_target_freq)(struct devfreq *this, unsigned long *freq); 314 315 /* For passive governor's internal use. Don't need to set them */ 316 struct devfreq *this; 317 struct notifier_block nb; 318 }; 319 #endif 320 321 #else /* !CONFIG_PM_DEVFREQ */ 322 static inline struct devfreq *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 int devfreq_remove_device(struct devfreq *devfreq) 331 { 332 return 0; 333 } 334 335 static inline struct devfreq *devm_devfreq_add_device(struct device *dev, 336 struct devfreq_dev_profile *profile, 337 const char *governor_name, 338 void *data) 339 { 340 return ERR_PTR(-ENOSYS); 341 } 342 343 static inline void devm_devfreq_remove_device(struct device *dev, 344 struct devfreq *devfreq) 345 { 346 } 347 348 static inline int devfreq_suspend_device(struct devfreq *devfreq) 349 { 350 return 0; 351 } 352 353 static inline int devfreq_resume_device(struct devfreq *devfreq) 354 { 355 return 0; 356 } 357 358 static inline void devfreq_suspend(void) {} 359 static inline void devfreq_resume(void) {} 360 361 static inline struct dev_pm_opp *devfreq_recommended_opp(struct device *dev, 362 unsigned long *freq, u32 flags) 363 { 364 return ERR_PTR(-EINVAL); 365 } 366 367 static inline int devfreq_register_opp_notifier(struct device *dev, 368 struct devfreq *devfreq) 369 { 370 return -EINVAL; 371 } 372 373 static inline int devfreq_unregister_opp_notifier(struct device *dev, 374 struct devfreq *devfreq) 375 { 376 return -EINVAL; 377 } 378 379 static inline int devm_devfreq_register_opp_notifier(struct device *dev, 380 struct devfreq *devfreq) 381 { 382 return -EINVAL; 383 } 384 385 static inline void devm_devfreq_unregister_opp_notifier(struct device *dev, 386 struct devfreq *devfreq) 387 { 388 } 389 390 static inline int devfreq_register_notifier(struct devfreq *devfreq, 391 struct notifier_block *nb, 392 unsigned int list) 393 { 394 return 0; 395 } 396 397 static inline int devfreq_unregister_notifier(struct devfreq *devfreq, 398 struct notifier_block *nb, 399 unsigned int list) 400 { 401 return 0; 402 } 403 404 static inline int devm_devfreq_register_notifier(struct device *dev, 405 struct devfreq *devfreq, 406 struct notifier_block *nb, 407 unsigned int list) 408 { 409 return 0; 410 } 411 412 static inline void devm_devfreq_unregister_notifier(struct device *dev, 413 struct devfreq *devfreq, 414 struct notifier_block *nb, 415 unsigned int list) 416 { 417 } 418 419 static inline struct devfreq *devfreq_get_devfreq_by_node(struct device_node *node) 420 { 421 return ERR_PTR(-ENODEV); 422 } 423 424 static inline struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev, 425 const char *phandle_name, int index) 426 { 427 return ERR_PTR(-ENODEV); 428 } 429 430 static inline int devfreq_update_stats(struct devfreq *df) 431 { 432 return -EINVAL; 433 } 434 #endif /* CONFIG_PM_DEVFREQ */ 435 436 #endif /* __LINUX_DEVFREQ_H__ */ 437