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 * @opp_table: Reference to OPP table of dev.parent, if one exists. 141 * @nb: notifier block used to notify devfreq object that it should 142 * reevaluate operable frequencies. Devfreq users may use 143 * devfreq.nb to the corresponding register notifier call chain. 144 * @work: delayed work for load monitoring. 145 * @previous_freq: previously configured frequency value. 146 * @last_status: devfreq user device info, performance statistics 147 * @data: Private data of the governor. The devfreq framework does not 148 * touch this. 149 * @user_min_freq_req: PM QoS minimum frequency request from user (via sysfs) 150 * @user_max_freq_req: PM QoS maximum frequency request from user (via sysfs) 151 * @scaling_min_freq: Limit minimum frequency requested by OPP interface 152 * @scaling_max_freq: Limit maximum frequency requested by OPP interface 153 * @stop_polling: devfreq polling status of a device. 154 * @suspend_freq: frequency of a device set during suspend phase. 155 * @resume_freq: frequency of a device set in resume phase. 156 * @suspend_count: suspend requests counter for a device. 157 * @stats: Statistics of devfreq device behavior 158 * @transition_notifier_list: list head of DEVFREQ_TRANSITION_NOTIFIER notifier 159 * @nb_min: Notifier block for DEV_PM_QOS_MIN_FREQUENCY 160 * @nb_max: Notifier block for DEV_PM_QOS_MAX_FREQUENCY 161 * 162 * This structure stores the devfreq information for a given device. 163 * 164 * Note that when a governor accesses entries in struct devfreq in its 165 * functions except for the context of callbacks defined in struct 166 * devfreq_governor, the governor should protect its access with the 167 * struct mutex lock in struct devfreq. A governor may use this mutex 168 * to protect its own private data in ``void *data`` as well. 169 */ 170 struct devfreq { 171 struct list_head node; 172 173 struct mutex lock; 174 struct device dev; 175 struct devfreq_dev_profile *profile; 176 const struct devfreq_governor *governor; 177 struct opp_table *opp_table; 178 struct notifier_block nb; 179 struct delayed_work work; 180 181 unsigned long previous_freq; 182 struct devfreq_dev_status last_status; 183 184 void *data; /* private data for governors */ 185 186 struct dev_pm_qos_request user_min_freq_req; 187 struct dev_pm_qos_request user_max_freq_req; 188 unsigned long scaling_min_freq; 189 unsigned long scaling_max_freq; 190 bool stop_polling; 191 192 unsigned long suspend_freq; 193 unsigned long resume_freq; 194 atomic_t suspend_count; 195 196 /* information for device frequency transitions */ 197 struct devfreq_stats stats; 198 199 struct srcu_notifier_head transition_notifier_list; 200 201 struct notifier_block nb_min; 202 struct notifier_block nb_max; 203 }; 204 205 struct devfreq_freqs { 206 unsigned long old; 207 unsigned long new; 208 }; 209 210 #if defined(CONFIG_PM_DEVFREQ) 211 struct devfreq *devfreq_add_device(struct device *dev, 212 struct devfreq_dev_profile *profile, 213 const char *governor_name, 214 void *data); 215 int devfreq_remove_device(struct devfreq *devfreq); 216 struct devfreq *devm_devfreq_add_device(struct device *dev, 217 struct devfreq_dev_profile *profile, 218 const char *governor_name, 219 void *data); 220 void devm_devfreq_remove_device(struct device *dev, struct devfreq *devfreq); 221 222 /* Supposed to be called by PM callbacks */ 223 int devfreq_suspend_device(struct devfreq *devfreq); 224 int devfreq_resume_device(struct devfreq *devfreq); 225 226 void devfreq_suspend(void); 227 void devfreq_resume(void); 228 229 /* update_devfreq() - Reevaluate the device and configure frequency */ 230 int update_devfreq(struct devfreq *devfreq); 231 232 /* Helper functions for devfreq user device driver with OPP. */ 233 struct dev_pm_opp *devfreq_recommended_opp(struct device *dev, 234 unsigned long *freq, u32 flags); 235 int devfreq_register_opp_notifier(struct device *dev, 236 struct devfreq *devfreq); 237 int devfreq_unregister_opp_notifier(struct device *dev, 238 struct devfreq *devfreq); 239 int devm_devfreq_register_opp_notifier(struct device *dev, 240 struct devfreq *devfreq); 241 void devm_devfreq_unregister_opp_notifier(struct device *dev, 242 struct devfreq *devfreq); 243 int devfreq_register_notifier(struct devfreq *devfreq, 244 struct notifier_block *nb, 245 unsigned int list); 246 int devfreq_unregister_notifier(struct devfreq *devfreq, 247 struct notifier_block *nb, 248 unsigned int list); 249 int devm_devfreq_register_notifier(struct device *dev, 250 struct devfreq *devfreq, 251 struct notifier_block *nb, 252 unsigned int list); 253 void devm_devfreq_unregister_notifier(struct device *dev, 254 struct devfreq *devfreq, 255 struct notifier_block *nb, 256 unsigned int list); 257 struct devfreq *devfreq_get_devfreq_by_node(struct device_node *node); 258 struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev, 259 const char *phandle_name, int index); 260 261 #if IS_ENABLED(CONFIG_DEVFREQ_GOV_SIMPLE_ONDEMAND) 262 /** 263 * struct devfreq_simple_ondemand_data - ``void *data`` fed to struct devfreq 264 * and devfreq_add_device 265 * @upthreshold: If the load is over this value, the frequency jumps. 266 * Specify 0 to use the default. Valid value = 0 to 100. 267 * @downdifferential: If the load is under upthreshold - downdifferential, 268 * the governor may consider slowing the frequency down. 269 * Specify 0 to use the default. Valid value = 0 to 100. 270 * downdifferential < upthreshold must hold. 271 * 272 * If the fed devfreq_simple_ondemand_data pointer is NULL to the governor, 273 * the governor uses the default values. 274 */ 275 struct devfreq_simple_ondemand_data { 276 unsigned int upthreshold; 277 unsigned int downdifferential; 278 }; 279 #endif 280 281 #if IS_ENABLED(CONFIG_DEVFREQ_GOV_PASSIVE) 282 /** 283 * struct devfreq_passive_data - ``void *data`` fed to struct devfreq 284 * and devfreq_add_device 285 * @parent: the devfreq instance of parent device. 286 * @get_target_freq: Optional callback, Returns desired operating frequency 287 * for the device using passive governor. That is called 288 * when passive governor should decide the next frequency 289 * by using the new frequency of parent devfreq device 290 * using governors except for passive governor. 291 * If the devfreq device has the specific method to decide 292 * the next frequency, should use this callback. 293 * @this: the devfreq instance of own device. 294 * @nb: the notifier block for DEVFREQ_TRANSITION_NOTIFIER list 295 * 296 * The devfreq_passive_data have to set the devfreq instance of parent 297 * device with governors except for the passive governor. But, don't need to 298 * initialize the 'this' and 'nb' field because the devfreq core will handle 299 * them. 300 */ 301 struct devfreq_passive_data { 302 /* Should set the devfreq instance of parent device */ 303 struct devfreq *parent; 304 305 /* Optional callback to decide the next frequency of passvice device */ 306 int (*get_target_freq)(struct devfreq *this, unsigned long *freq); 307 308 /* For passive governor's internal use. Don't need to set them */ 309 struct devfreq *this; 310 struct notifier_block nb; 311 }; 312 #endif 313 314 #else /* !CONFIG_PM_DEVFREQ */ 315 static inline struct devfreq *devfreq_add_device(struct device *dev, 316 struct devfreq_dev_profile *profile, 317 const char *governor_name, 318 void *data) 319 { 320 return ERR_PTR(-ENOSYS); 321 } 322 323 static inline int devfreq_remove_device(struct devfreq *devfreq) 324 { 325 return 0; 326 } 327 328 static inline struct devfreq *devm_devfreq_add_device(struct device *dev, 329 struct devfreq_dev_profile *profile, 330 const char *governor_name, 331 void *data) 332 { 333 return ERR_PTR(-ENOSYS); 334 } 335 336 static inline void devm_devfreq_remove_device(struct device *dev, 337 struct devfreq *devfreq) 338 { 339 } 340 341 static inline int devfreq_suspend_device(struct devfreq *devfreq) 342 { 343 return 0; 344 } 345 346 static inline int devfreq_resume_device(struct devfreq *devfreq) 347 { 348 return 0; 349 } 350 351 static inline void devfreq_suspend(void) {} 352 static inline void devfreq_resume(void) {} 353 354 static inline struct dev_pm_opp *devfreq_recommended_opp(struct device *dev, 355 unsigned long *freq, u32 flags) 356 { 357 return ERR_PTR(-EINVAL); 358 } 359 360 static inline int devfreq_register_opp_notifier(struct device *dev, 361 struct devfreq *devfreq) 362 { 363 return -EINVAL; 364 } 365 366 static inline int devfreq_unregister_opp_notifier(struct device *dev, 367 struct devfreq *devfreq) 368 { 369 return -EINVAL; 370 } 371 372 static inline int devm_devfreq_register_opp_notifier(struct device *dev, 373 struct devfreq *devfreq) 374 { 375 return -EINVAL; 376 } 377 378 static inline void devm_devfreq_unregister_opp_notifier(struct device *dev, 379 struct devfreq *devfreq) 380 { 381 } 382 383 static inline int devfreq_register_notifier(struct devfreq *devfreq, 384 struct notifier_block *nb, 385 unsigned int list) 386 { 387 return 0; 388 } 389 390 static inline int devfreq_unregister_notifier(struct devfreq *devfreq, 391 struct notifier_block *nb, 392 unsigned int list) 393 { 394 return 0; 395 } 396 397 static inline int devm_devfreq_register_notifier(struct device *dev, 398 struct devfreq *devfreq, 399 struct notifier_block *nb, 400 unsigned int list) 401 { 402 return 0; 403 } 404 405 static inline void devm_devfreq_unregister_notifier(struct device *dev, 406 struct devfreq *devfreq, 407 struct notifier_block *nb, 408 unsigned int list) 409 { 410 } 411 412 static inline struct devfreq *devfreq_get_devfreq_by_node(struct device_node *node) 413 { 414 return ERR_PTR(-ENODEV); 415 } 416 417 static inline struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev, 418 const char *phandle_name, int index) 419 { 420 return ERR_PTR(-ENODEV); 421 } 422 423 static inline int devfreq_update_stats(struct devfreq *df) 424 { 425 return -EINVAL; 426 } 427 #endif /* CONFIG_PM_DEVFREQ */ 428 429 #endif /* __LINUX_DEVFREQ_H__ */ 430