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