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 /* update_devfreq() - Reevaluate the device and configure frequency */ 232 int update_devfreq(struct devfreq *devfreq); 233 234 /* Helper functions for devfreq user device driver with OPP. */ 235 struct dev_pm_opp *devfreq_recommended_opp(struct device *dev, 236 unsigned long *freq, u32 flags); 237 int devfreq_register_opp_notifier(struct device *dev, 238 struct devfreq *devfreq); 239 int devfreq_unregister_opp_notifier(struct device *dev, 240 struct devfreq *devfreq); 241 int devm_devfreq_register_opp_notifier(struct device *dev, 242 struct devfreq *devfreq); 243 void devm_devfreq_unregister_opp_notifier(struct device *dev, 244 struct devfreq *devfreq); 245 int devfreq_register_notifier(struct devfreq *devfreq, 246 struct notifier_block *nb, 247 unsigned int list); 248 int devfreq_unregister_notifier(struct devfreq *devfreq, 249 struct notifier_block *nb, 250 unsigned int list); 251 int devm_devfreq_register_notifier(struct device *dev, 252 struct devfreq *devfreq, 253 struct notifier_block *nb, 254 unsigned int list); 255 void devm_devfreq_unregister_notifier(struct device *dev, 256 struct devfreq *devfreq, 257 struct notifier_block *nb, 258 unsigned int list); 259 struct devfreq *devfreq_get_devfreq_by_node(struct device_node *node); 260 struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev, 261 const char *phandle_name, int index); 262 263 #if IS_ENABLED(CONFIG_DEVFREQ_GOV_SIMPLE_ONDEMAND) 264 /** 265 * struct devfreq_simple_ondemand_data - ``void *data`` fed to struct devfreq 266 * and devfreq_add_device 267 * @upthreshold: If the load is over this value, the frequency jumps. 268 * Specify 0 to use the default. Valid value = 0 to 100. 269 * @downdifferential: If the load is under upthreshold - downdifferential, 270 * the governor may consider slowing the frequency down. 271 * Specify 0 to use the default. Valid value = 0 to 100. 272 * downdifferential < upthreshold must hold. 273 * 274 * If the fed devfreq_simple_ondemand_data pointer is NULL to the governor, 275 * the governor uses the default values. 276 */ 277 struct devfreq_simple_ondemand_data { 278 unsigned int upthreshold; 279 unsigned int downdifferential; 280 }; 281 #endif 282 283 #if IS_ENABLED(CONFIG_DEVFREQ_GOV_PASSIVE) 284 /** 285 * struct devfreq_passive_data - ``void *data`` fed to struct devfreq 286 * and devfreq_add_device 287 * @parent: the devfreq instance of parent device. 288 * @get_target_freq: Optional callback, Returns desired operating frequency 289 * for the device using passive governor. That is called 290 * when passive governor should decide the next frequency 291 * by using the new frequency of parent devfreq device 292 * using governors except for passive governor. 293 * If the devfreq device has the specific method to decide 294 * the next frequency, should use this callback. 295 * @this: the devfreq instance of own device. 296 * @nb: the notifier block for DEVFREQ_TRANSITION_NOTIFIER list 297 * 298 * The devfreq_passive_data have to set the devfreq instance of parent 299 * device with governors except for the passive governor. But, don't need to 300 * initialize the 'this' and 'nb' field because the devfreq core will handle 301 * them. 302 */ 303 struct devfreq_passive_data { 304 /* Should set the devfreq instance of parent device */ 305 struct devfreq *parent; 306 307 /* Optional callback to decide the next frequency of passvice device */ 308 int (*get_target_freq)(struct devfreq *this, unsigned long *freq); 309 310 /* For passive governor's internal use. Don't need to set them */ 311 struct devfreq *this; 312 struct notifier_block nb; 313 }; 314 #endif 315 316 #else /* !CONFIG_PM_DEVFREQ */ 317 static inline struct devfreq *devfreq_add_device(struct device *dev, 318 struct devfreq_dev_profile *profile, 319 const char *governor_name, 320 void *data) 321 { 322 return ERR_PTR(-ENOSYS); 323 } 324 325 static inline int devfreq_remove_device(struct devfreq *devfreq) 326 { 327 return 0; 328 } 329 330 static inline struct devfreq *devm_devfreq_add_device(struct device *dev, 331 struct devfreq_dev_profile *profile, 332 const char *governor_name, 333 void *data) 334 { 335 return ERR_PTR(-ENOSYS); 336 } 337 338 static inline void devm_devfreq_remove_device(struct device *dev, 339 struct devfreq *devfreq) 340 { 341 } 342 343 static inline int devfreq_suspend_device(struct devfreq *devfreq) 344 { 345 return 0; 346 } 347 348 static inline int devfreq_resume_device(struct devfreq *devfreq) 349 { 350 return 0; 351 } 352 353 static inline void devfreq_suspend(void) {} 354 static inline void devfreq_resume(void) {} 355 356 static inline struct dev_pm_opp *devfreq_recommended_opp(struct device *dev, 357 unsigned long *freq, u32 flags) 358 { 359 return ERR_PTR(-EINVAL); 360 } 361 362 static inline int devfreq_register_opp_notifier(struct device *dev, 363 struct devfreq *devfreq) 364 { 365 return -EINVAL; 366 } 367 368 static inline int devfreq_unregister_opp_notifier(struct device *dev, 369 struct devfreq *devfreq) 370 { 371 return -EINVAL; 372 } 373 374 static inline int devm_devfreq_register_opp_notifier(struct device *dev, 375 struct devfreq *devfreq) 376 { 377 return -EINVAL; 378 } 379 380 static inline void devm_devfreq_unregister_opp_notifier(struct device *dev, 381 struct devfreq *devfreq) 382 { 383 } 384 385 static inline int devfreq_register_notifier(struct devfreq *devfreq, 386 struct notifier_block *nb, 387 unsigned int list) 388 { 389 return 0; 390 } 391 392 static inline int devfreq_unregister_notifier(struct devfreq *devfreq, 393 struct notifier_block *nb, 394 unsigned int list) 395 { 396 return 0; 397 } 398 399 static inline int devm_devfreq_register_notifier(struct device *dev, 400 struct devfreq *devfreq, 401 struct notifier_block *nb, 402 unsigned int list) 403 { 404 return 0; 405 } 406 407 static inline void devm_devfreq_unregister_notifier(struct device *dev, 408 struct devfreq *devfreq, 409 struct notifier_block *nb, 410 unsigned int list) 411 { 412 } 413 414 static inline struct devfreq *devfreq_get_devfreq_by_node(struct device_node *node) 415 { 416 return ERR_PTR(-ENODEV); 417 } 418 419 static inline struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev, 420 const char *phandle_name, int index) 421 { 422 return ERR_PTR(-ENODEV); 423 } 424 425 static inline int devfreq_update_stats(struct devfreq *df) 426 { 427 return -EINVAL; 428 } 429 #endif /* CONFIG_PM_DEVFREQ */ 430 431 #endif /* __LINUX_DEVFREQ_H__ */ 432