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 /* DEVFREQ governor name */ 19 #define DEVFREQ_GOV_SIMPLE_ONDEMAND "simple_ondemand" 20 #define DEVFREQ_GOV_PERFORMANCE "performance" 21 #define DEVFREQ_GOV_POWERSAVE "powersave" 22 #define DEVFREQ_GOV_USERSPACE "userspace" 23 #define DEVFREQ_GOV_PASSIVE "passive" 24 25 /* DEVFREQ notifier interface */ 26 #define DEVFREQ_TRANSITION_NOTIFIER (0) 27 28 /* Transition notifiers of DEVFREQ_TRANSITION_NOTIFIER */ 29 #define DEVFREQ_PRECHANGE (0) 30 #define DEVFREQ_POSTCHANGE (1) 31 32 /* DEVFREQ work timers */ 33 enum devfreq_timer { 34 DEVFREQ_TIMER_DEFERRABLE = 0, 35 DEVFREQ_TIMER_DELAYED, 36 DEVFREQ_TIMER_NUM, 37 }; 38 39 struct devfreq; 40 struct devfreq_governor; 41 struct thermal_cooling_device; 42 43 /** 44 * struct devfreq_dev_status - Data given from devfreq user device to 45 * governors. Represents the performance 46 * statistics. 47 * @total_time: The total time represented by this instance of 48 * devfreq_dev_status 49 * @busy_time: The time that the device was working among the 50 * total_time. 51 * @current_frequency: The operating frequency. 52 * @private_data: An entry not specified by the devfreq framework. 53 * A device and a specific governor may have their 54 * own protocol with private_data. However, because 55 * this is governor-specific, a governor using this 56 * will be only compatible with devices aware of it. 57 */ 58 struct devfreq_dev_status { 59 /* both since the last measure */ 60 unsigned long total_time; 61 unsigned long busy_time; 62 unsigned long current_frequency; 63 void *private_data; 64 }; 65 66 /* 67 * The resulting frequency should be at most this. (this bound is the 68 * least upper bound; thus, the resulting freq should be lower or same) 69 * If the flag is not set, the resulting frequency should be at most the 70 * bound (greatest lower bound) 71 */ 72 #define DEVFREQ_FLAG_LEAST_UPPER_BOUND 0x1 73 74 /** 75 * struct devfreq_dev_profile - Devfreq's user device profile 76 * @initial_freq: The operating frequency when devfreq_add_device() is 77 * called. 78 * @polling_ms: The polling interval in ms. 0 disables polling. 79 * @timer: Timer type is either deferrable or delayed timer. 80 * @target: The device should set its operating frequency at 81 * freq or lowest-upper-than-freq value. If freq is 82 * higher than any operable frequency, set maximum. 83 * Before returning, target function should set 84 * freq at the current frequency. 85 * The "flags" parameter's possible values are 86 * explained above with "DEVFREQ_FLAG_*" macros. 87 * @get_dev_status: The device should provide the current performance 88 * status to devfreq. Governors are recommended not to 89 * use this directly. Instead, governors are recommended 90 * to use devfreq_update_stats() along with 91 * devfreq.last_status. 92 * @get_cur_freq: The device should provide the current frequency 93 * at which it is operating. 94 * @exit: An optional callback that is called when devfreq 95 * is removing the devfreq object due to error or 96 * from devfreq_remove_device() call. If the user 97 * has registered devfreq->nb at a notifier-head, 98 * this is the time to unregister it. 99 * @freq_table: Optional list of frequencies to support statistics 100 * and freq_table must be generated in ascending order. 101 * @max_state: The size of freq_table. 102 * 103 * @is_cooling_device: A self-explanatory boolean giving the device a 104 * cooling effect property. 105 */ 106 struct devfreq_dev_profile { 107 unsigned long initial_freq; 108 unsigned int polling_ms; 109 enum devfreq_timer timer; 110 bool is_cooling_device; 111 112 int (*target)(struct device *dev, unsigned long *freq, u32 flags); 113 int (*get_dev_status)(struct device *dev, 114 struct devfreq_dev_status *stat); 115 int (*get_cur_freq)(struct device *dev, unsigned long *freq); 116 void (*exit)(struct device *dev); 117 118 unsigned long *freq_table; 119 unsigned int max_state; 120 }; 121 122 /** 123 * struct devfreq_stats - Statistics of devfreq device behavior 124 * @total_trans: Number of devfreq transitions. 125 * @trans_table: Statistics of devfreq transitions. 126 * @time_in_state: Statistics of devfreq states. 127 * @last_update: The last time stats were updated. 128 */ 129 struct devfreq_stats { 130 unsigned int total_trans; 131 unsigned int *trans_table; 132 u64 *time_in_state; 133 u64 last_update; 134 }; 135 136 /** 137 * struct devfreq - Device devfreq structure 138 * @node: list node - contains the devices with devfreq that have been 139 * registered. 140 * @lock: a mutex to protect accessing devfreq. 141 * @dev: device registered by devfreq class. dev.parent is the device 142 * using devfreq. 143 * @profile: device-specific devfreq profile 144 * @governor: method how to choose frequency based on the usage. 145 * @opp_table: Reference to OPP table of dev.parent, if one exists. 146 * @nb: notifier block used to notify devfreq object that it should 147 * reevaluate operable frequencies. Devfreq users may use 148 * devfreq.nb to the corresponding register notifier call chain. 149 * @work: delayed work for load monitoring. 150 * @previous_freq: previously configured frequency value. 151 * @last_status: devfreq user device info, performance statistics 152 * @data: Private data of the governor. The devfreq framework does not 153 * touch this. 154 * @user_min_freq_req: PM QoS minimum frequency request from user (via sysfs) 155 * @user_max_freq_req: PM QoS maximum frequency request from user (via sysfs) 156 * @scaling_min_freq: Limit minimum frequency requested by OPP interface 157 * @scaling_max_freq: Limit maximum frequency requested by OPP interface 158 * @stop_polling: devfreq polling status of a device. 159 * @suspend_freq: frequency of a device set during suspend phase. 160 * @resume_freq: frequency of a device set in resume phase. 161 * @suspend_count: suspend requests counter for a device. 162 * @stats: Statistics of devfreq device behavior 163 * @transition_notifier_list: list head of DEVFREQ_TRANSITION_NOTIFIER notifier 164 * @cdev: Cooling device pointer if the devfreq has cooling property 165 * @nb_min: Notifier block for DEV_PM_QOS_MIN_FREQUENCY 166 * @nb_max: Notifier block for DEV_PM_QOS_MAX_FREQUENCY 167 * 168 * This structure stores the devfreq information for a given device. 169 * 170 * Note that when a governor accesses entries in struct devfreq in its 171 * functions except for the context of callbacks defined in struct 172 * devfreq_governor, the governor should protect its access with the 173 * struct mutex lock in struct devfreq. A governor may use this mutex 174 * to protect its own private data in ``void *data`` as well. 175 */ 176 struct devfreq { 177 struct list_head node; 178 179 struct mutex lock; 180 struct device dev; 181 struct devfreq_dev_profile *profile; 182 const struct devfreq_governor *governor; 183 struct opp_table *opp_table; 184 struct notifier_block nb; 185 struct delayed_work work; 186 187 unsigned long previous_freq; 188 struct devfreq_dev_status last_status; 189 190 void *data; /* private data for governors */ 191 192 struct dev_pm_qos_request user_min_freq_req; 193 struct dev_pm_qos_request user_max_freq_req; 194 unsigned long scaling_min_freq; 195 unsigned long scaling_max_freq; 196 bool stop_polling; 197 198 unsigned long suspend_freq; 199 unsigned long resume_freq; 200 atomic_t suspend_count; 201 202 /* information for device frequency transitions */ 203 struct devfreq_stats stats; 204 205 struct srcu_notifier_head transition_notifier_list; 206 207 /* Pointer to the cooling device if used for thermal mitigation */ 208 struct thermal_cooling_device *cdev; 209 210 struct notifier_block nb_min; 211 struct notifier_block nb_max; 212 }; 213 214 struct devfreq_freqs { 215 unsigned long old; 216 unsigned long new; 217 }; 218 219 #if defined(CONFIG_PM_DEVFREQ) 220 struct devfreq *devfreq_add_device(struct device *dev, 221 struct devfreq_dev_profile *profile, 222 const char *governor_name, 223 void *data); 224 int devfreq_remove_device(struct devfreq *devfreq); 225 struct devfreq *devm_devfreq_add_device(struct device *dev, 226 struct devfreq_dev_profile *profile, 227 const char *governor_name, 228 void *data); 229 void devm_devfreq_remove_device(struct device *dev, struct devfreq *devfreq); 230 231 /* Supposed to be called by PM callbacks */ 232 int devfreq_suspend_device(struct devfreq *devfreq); 233 int devfreq_resume_device(struct devfreq *devfreq); 234 235 void devfreq_suspend(void); 236 void devfreq_resume(void); 237 238 /* update_devfreq() - Reevaluate the device and configure frequency */ 239 int update_devfreq(struct devfreq *devfreq); 240 241 /* Helper functions for devfreq user device driver with OPP. */ 242 struct dev_pm_opp *devfreq_recommended_opp(struct device *dev, 243 unsigned long *freq, u32 flags); 244 int devfreq_register_opp_notifier(struct device *dev, 245 struct devfreq *devfreq); 246 int devfreq_unregister_opp_notifier(struct device *dev, 247 struct devfreq *devfreq); 248 int devm_devfreq_register_opp_notifier(struct device *dev, 249 struct devfreq *devfreq); 250 void devm_devfreq_unregister_opp_notifier(struct device *dev, 251 struct devfreq *devfreq); 252 int devfreq_register_notifier(struct devfreq *devfreq, 253 struct notifier_block *nb, 254 unsigned int list); 255 int devfreq_unregister_notifier(struct devfreq *devfreq, 256 struct notifier_block *nb, 257 unsigned int list); 258 int devm_devfreq_register_notifier(struct device *dev, 259 struct devfreq *devfreq, 260 struct notifier_block *nb, 261 unsigned int list); 262 void devm_devfreq_unregister_notifier(struct device *dev, 263 struct devfreq *devfreq, 264 struct notifier_block *nb, 265 unsigned int list); 266 struct devfreq *devfreq_get_devfreq_by_node(struct device_node *node); 267 struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev, 268 const char *phandle_name, int index); 269 270 #if IS_ENABLED(CONFIG_DEVFREQ_GOV_SIMPLE_ONDEMAND) 271 /** 272 * struct devfreq_simple_ondemand_data - ``void *data`` fed to struct devfreq 273 * and devfreq_add_device 274 * @upthreshold: If the load is over this value, the frequency jumps. 275 * Specify 0 to use the default. Valid value = 0 to 100. 276 * @downdifferential: If the load is under upthreshold - downdifferential, 277 * the governor may consider slowing the frequency down. 278 * Specify 0 to use the default. Valid value = 0 to 100. 279 * downdifferential < upthreshold must hold. 280 * 281 * If the fed devfreq_simple_ondemand_data pointer is NULL to the governor, 282 * the governor uses the default values. 283 */ 284 struct devfreq_simple_ondemand_data { 285 unsigned int upthreshold; 286 unsigned int downdifferential; 287 }; 288 #endif 289 290 #if IS_ENABLED(CONFIG_DEVFREQ_GOV_PASSIVE) 291 /** 292 * struct devfreq_passive_data - ``void *data`` fed to struct devfreq 293 * and devfreq_add_device 294 * @parent: the devfreq instance of parent device. 295 * @get_target_freq: Optional callback, Returns desired operating frequency 296 * for the device using passive governor. That is called 297 * when passive governor should decide the next frequency 298 * by using the new frequency of parent devfreq device 299 * using governors except for passive governor. 300 * If the devfreq device has the specific method to decide 301 * the next frequency, should use this callback. 302 * @this: the devfreq instance of own device. 303 * @nb: the notifier block for DEVFREQ_TRANSITION_NOTIFIER list 304 * 305 * The devfreq_passive_data have to set the devfreq instance of parent 306 * device with governors except for the passive governor. But, don't need to 307 * initialize the 'this' and 'nb' field because the devfreq core will handle 308 * them. 309 */ 310 struct devfreq_passive_data { 311 /* Should set the devfreq instance of parent device */ 312 struct devfreq *parent; 313 314 /* Optional callback to decide the next frequency of passvice device */ 315 int (*get_target_freq)(struct devfreq *this, unsigned long *freq); 316 317 /* For passive governor's internal use. Don't need to set them */ 318 struct devfreq *this; 319 struct notifier_block nb; 320 }; 321 #endif 322 323 #else /* !CONFIG_PM_DEVFREQ */ 324 static inline struct devfreq *devfreq_add_device(struct device *dev, 325 struct devfreq_dev_profile *profile, 326 const char *governor_name, 327 void *data) 328 { 329 return ERR_PTR(-ENOSYS); 330 } 331 332 static inline int devfreq_remove_device(struct devfreq *devfreq) 333 { 334 return 0; 335 } 336 337 static inline struct devfreq *devm_devfreq_add_device(struct device *dev, 338 struct devfreq_dev_profile *profile, 339 const char *governor_name, 340 void *data) 341 { 342 return ERR_PTR(-ENOSYS); 343 } 344 345 static inline void devm_devfreq_remove_device(struct device *dev, 346 struct devfreq *devfreq) 347 { 348 } 349 350 static inline int devfreq_suspend_device(struct devfreq *devfreq) 351 { 352 return 0; 353 } 354 355 static inline int devfreq_resume_device(struct devfreq *devfreq) 356 { 357 return 0; 358 } 359 360 static inline void devfreq_suspend(void) {} 361 static inline void devfreq_resume(void) {} 362 363 static inline struct dev_pm_opp *devfreq_recommended_opp(struct device *dev, 364 unsigned long *freq, u32 flags) 365 { 366 return ERR_PTR(-EINVAL); 367 } 368 369 static inline int devfreq_register_opp_notifier(struct device *dev, 370 struct devfreq *devfreq) 371 { 372 return -EINVAL; 373 } 374 375 static inline int devfreq_unregister_opp_notifier(struct device *dev, 376 struct devfreq *devfreq) 377 { 378 return -EINVAL; 379 } 380 381 static inline int devm_devfreq_register_opp_notifier(struct device *dev, 382 struct devfreq *devfreq) 383 { 384 return -EINVAL; 385 } 386 387 static inline void devm_devfreq_unregister_opp_notifier(struct device *dev, 388 struct devfreq *devfreq) 389 { 390 } 391 392 static inline int devfreq_register_notifier(struct devfreq *devfreq, 393 struct notifier_block *nb, 394 unsigned int list) 395 { 396 return 0; 397 } 398 399 static inline int devfreq_unregister_notifier(struct devfreq *devfreq, 400 struct notifier_block *nb, 401 unsigned int list) 402 { 403 return 0; 404 } 405 406 static inline int devm_devfreq_register_notifier(struct device *dev, 407 struct devfreq *devfreq, 408 struct notifier_block *nb, 409 unsigned int list) 410 { 411 return 0; 412 } 413 414 static inline void devm_devfreq_unregister_notifier(struct device *dev, 415 struct devfreq *devfreq, 416 struct notifier_block *nb, 417 unsigned int list) 418 { 419 } 420 421 static inline struct devfreq *devfreq_get_devfreq_by_node(struct device_node *node) 422 { 423 return ERR_PTR(-ENODEV); 424 } 425 426 static inline struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev, 427 const char *phandle_name, int index) 428 { 429 return ERR_PTR(-ENODEV); 430 } 431 432 static inline int devfreq_update_stats(struct devfreq *df) 433 { 434 return -EINVAL; 435 } 436 #endif /* CONFIG_PM_DEVFREQ */ 437 438 #endif /* __LINUX_DEVFREQ_H__ */ 439