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 devfreq_cpu_data; 42 struct thermal_cooling_device; 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 * @is_cooling_device: A self-explanatory boolean giving the device a 105 * cooling effect property. 106 */ 107 struct devfreq_dev_profile { 108 unsigned long initial_freq; 109 unsigned int polling_ms; 110 enum devfreq_timer timer; 111 bool is_cooling_device; 112 113 int (*target)(struct device *dev, unsigned long *freq, u32 flags); 114 int (*get_dev_status)(struct device *dev, 115 struct devfreq_dev_status *stat); 116 int (*get_cur_freq)(struct device *dev, unsigned long *freq); 117 void (*exit)(struct device *dev); 118 119 unsigned long *freq_table; 120 unsigned int max_state; 121 }; 122 123 /** 124 * struct devfreq_stats - Statistics of devfreq device behavior 125 * @total_trans: Number of devfreq transitions. 126 * @trans_table: Statistics of devfreq transitions. 127 * @time_in_state: Statistics of devfreq states. 128 * @last_update: The last time stats were updated. 129 */ 130 struct devfreq_stats { 131 unsigned int total_trans; 132 unsigned int *trans_table; 133 u64 *time_in_state; 134 u64 last_update; 135 }; 136 137 /** 138 * struct devfreq - Device devfreq structure 139 * @node: list node - contains the devices with devfreq that have been 140 * registered. 141 * @lock: a mutex to protect accessing devfreq. 142 * @dev: device registered by devfreq class. dev.parent is the device 143 * using devfreq. 144 * @profile: device-specific devfreq profile 145 * @governor: method how to choose frequency based on the usage. 146 * @opp_table: Reference to OPP table of dev.parent, if one exists. 147 * @nb: notifier block used to notify devfreq object that it should 148 * reevaluate operable frequencies. Devfreq users may use 149 * devfreq.nb to the corresponding register notifier call chain. 150 * @work: delayed work for load monitoring. 151 * @previous_freq: previously configured frequency value. 152 * @last_status: devfreq user device info, performance statistics 153 * @data: Private data of the governor. The devfreq framework does not 154 * touch this. 155 * @user_min_freq_req: PM QoS minimum frequency request from user (via sysfs) 156 * @user_max_freq_req: PM QoS maximum frequency request from user (via sysfs) 157 * @scaling_min_freq: Limit minimum frequency requested by OPP interface 158 * @scaling_max_freq: Limit maximum frequency requested by OPP interface 159 * @stop_polling: devfreq polling status of a device. 160 * @suspend_freq: frequency of a device set during suspend phase. 161 * @resume_freq: frequency of a device set in resume phase. 162 * @suspend_count: suspend requests counter for a device. 163 * @stats: Statistics of devfreq device behavior 164 * @transition_notifier_list: list head of DEVFREQ_TRANSITION_NOTIFIER notifier 165 * @cdev: Cooling device pointer if the devfreq has cooling property 166 * @nb_min: Notifier block for DEV_PM_QOS_MIN_FREQUENCY 167 * @nb_max: Notifier block for DEV_PM_QOS_MAX_FREQUENCY 168 * 169 * This structure stores the devfreq information for a given device. 170 * 171 * Note that when a governor accesses entries in struct devfreq in its 172 * functions except for the context of callbacks defined in struct 173 * devfreq_governor, the governor should protect its access with the 174 * struct mutex lock in struct devfreq. A governor may use this mutex 175 * to protect its own private data in ``void *data`` as well. 176 */ 177 struct devfreq { 178 struct list_head node; 179 180 struct mutex lock; 181 struct device dev; 182 struct devfreq_dev_profile *profile; 183 const struct devfreq_governor *governor; 184 struct opp_table *opp_table; 185 struct notifier_block nb; 186 struct delayed_work work; 187 188 unsigned long previous_freq; 189 struct devfreq_dev_status last_status; 190 191 void *data; /* private data for governors */ 192 193 struct dev_pm_qos_request user_min_freq_req; 194 struct dev_pm_qos_request user_max_freq_req; 195 unsigned long scaling_min_freq; 196 unsigned long scaling_max_freq; 197 bool stop_polling; 198 199 unsigned long suspend_freq; 200 unsigned long resume_freq; 201 atomic_t suspend_count; 202 203 /* information for device frequency transitions */ 204 struct devfreq_stats stats; 205 206 struct srcu_notifier_head transition_notifier_list; 207 208 /* Pointer to the cooling device if used for thermal mitigation */ 209 struct thermal_cooling_device *cdev; 210 211 struct notifier_block nb_min; 212 struct notifier_block nb_max; 213 }; 214 215 struct devfreq_freqs { 216 unsigned long old; 217 unsigned long new; 218 }; 219 220 #if defined(CONFIG_PM_DEVFREQ) 221 struct devfreq *devfreq_add_device(struct device *dev, 222 struct devfreq_dev_profile *profile, 223 const char *governor_name, 224 void *data); 225 int devfreq_remove_device(struct devfreq *devfreq); 226 struct devfreq *devm_devfreq_add_device(struct device *dev, 227 struct devfreq_dev_profile *profile, 228 const char *governor_name, 229 void *data); 230 void devm_devfreq_remove_device(struct device *dev, struct devfreq *devfreq); 231 232 /* Supposed to be called by PM callbacks */ 233 int devfreq_suspend_device(struct devfreq *devfreq); 234 int devfreq_resume_device(struct devfreq *devfreq); 235 236 void devfreq_suspend(void); 237 void devfreq_resume(void); 238 239 /* update_devfreq() - Reevaluate the device and configure frequency */ 240 int update_devfreq(struct devfreq *devfreq); 241 242 /* Helper functions for devfreq user device driver with OPP. */ 243 struct dev_pm_opp *devfreq_recommended_opp(struct device *dev, 244 unsigned long *freq, u32 flags); 245 int devfreq_register_opp_notifier(struct device *dev, 246 struct devfreq *devfreq); 247 int devfreq_unregister_opp_notifier(struct device *dev, 248 struct devfreq *devfreq); 249 int devm_devfreq_register_opp_notifier(struct device *dev, 250 struct devfreq *devfreq); 251 void devm_devfreq_unregister_opp_notifier(struct device *dev, 252 struct devfreq *devfreq); 253 int devfreq_register_notifier(struct devfreq *devfreq, 254 struct notifier_block *nb, 255 unsigned int list); 256 int devfreq_unregister_notifier(struct devfreq *devfreq, 257 struct notifier_block *nb, 258 unsigned int list); 259 int devm_devfreq_register_notifier(struct device *dev, 260 struct devfreq *devfreq, 261 struct notifier_block *nb, 262 unsigned int list); 263 void devm_devfreq_unregister_notifier(struct device *dev, 264 struct devfreq *devfreq, 265 struct notifier_block *nb, 266 unsigned int list); 267 struct devfreq *devfreq_get_devfreq_by_node(struct device_node *node); 268 struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev, 269 const char *phandle_name, int index); 270 271 #if IS_ENABLED(CONFIG_DEVFREQ_GOV_SIMPLE_ONDEMAND) 272 /** 273 * struct devfreq_simple_ondemand_data - ``void *data`` fed to struct devfreq 274 * and devfreq_add_device 275 * @upthreshold: If the load is over this value, the frequency jumps. 276 * Specify 0 to use the default. Valid value = 0 to 100. 277 * @downdifferential: If the load is under upthreshold - downdifferential, 278 * the governor may consider slowing the frequency down. 279 * Specify 0 to use the default. Valid value = 0 to 100. 280 * downdifferential < upthreshold must hold. 281 * 282 * If the fed devfreq_simple_ondemand_data pointer is NULL to the governor, 283 * the governor uses the default values. 284 */ 285 struct devfreq_simple_ondemand_data { 286 unsigned int upthreshold; 287 unsigned int downdifferential; 288 }; 289 #endif 290 291 #if IS_ENABLED(CONFIG_DEVFREQ_GOV_PASSIVE) 292 enum devfreq_parent_dev_type { 293 DEVFREQ_PARENT_DEV, 294 CPUFREQ_PARENT_DEV, 295 }; 296 297 /** 298 * struct devfreq_passive_data - ``void *data`` fed to struct devfreq 299 * and devfreq_add_device 300 * @parent: the devfreq instance of parent device. 301 * @get_target_freq: Optional callback, Returns desired operating frequency 302 * for the device using passive governor. That is called 303 * when passive governor should decide the next frequency 304 * by using the new frequency of parent devfreq device 305 * using governors except for passive governor. 306 * If the devfreq device has the specific method to decide 307 * the next frequency, should use this callback. 308 * @parent_type: the parent type of the device. 309 * @this: the devfreq instance of own device. 310 * @nb: the notifier block for DEVFREQ_TRANSITION_NOTIFIER or 311 * CPUFREQ_TRANSITION_NOTIFIER list. 312 * @cpu_data_list: the list of cpu frequency data for all cpufreq_policy. 313 * 314 * The devfreq_passive_data have to set the devfreq instance of parent 315 * device with governors except for the passive governor. But, don't need to 316 * initialize the 'this' and 'nb' field because the devfreq core will handle 317 * them. 318 */ 319 struct devfreq_passive_data { 320 /* Should set the devfreq instance of parent device */ 321 struct devfreq *parent; 322 323 /* Optional callback to decide the next frequency of passvice device */ 324 int (*get_target_freq)(struct devfreq *this, unsigned long *freq); 325 326 /* Should set the type of parent device */ 327 enum devfreq_parent_dev_type parent_type; 328 329 /* For passive governor's internal use. Don't need to set them */ 330 struct devfreq *this; 331 struct notifier_block nb; 332 struct list_head cpu_data_list; 333 }; 334 #endif 335 336 #else /* !CONFIG_PM_DEVFREQ */ 337 static inline struct devfreq *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 int devfreq_remove_device(struct devfreq *devfreq) 346 { 347 return 0; 348 } 349 350 static inline struct devfreq *devm_devfreq_add_device(struct device *dev, 351 struct devfreq_dev_profile *profile, 352 const char *governor_name, 353 void *data) 354 { 355 return ERR_PTR(-ENOSYS); 356 } 357 358 static inline void devm_devfreq_remove_device(struct device *dev, 359 struct devfreq *devfreq) 360 { 361 } 362 363 static inline int devfreq_suspend_device(struct devfreq *devfreq) 364 { 365 return 0; 366 } 367 368 static inline int devfreq_resume_device(struct devfreq *devfreq) 369 { 370 return 0; 371 } 372 373 static inline void devfreq_suspend(void) {} 374 static inline void devfreq_resume(void) {} 375 376 static inline struct dev_pm_opp *devfreq_recommended_opp(struct device *dev, 377 unsigned long *freq, u32 flags) 378 { 379 return ERR_PTR(-EINVAL); 380 } 381 382 static inline int devfreq_register_opp_notifier(struct device *dev, 383 struct devfreq *devfreq) 384 { 385 return -EINVAL; 386 } 387 388 static inline int devfreq_unregister_opp_notifier(struct device *dev, 389 struct devfreq *devfreq) 390 { 391 return -EINVAL; 392 } 393 394 static inline int devm_devfreq_register_opp_notifier(struct device *dev, 395 struct devfreq *devfreq) 396 { 397 return -EINVAL; 398 } 399 400 static inline void devm_devfreq_unregister_opp_notifier(struct device *dev, 401 struct devfreq *devfreq) 402 { 403 } 404 405 static inline int devfreq_register_notifier(struct devfreq *devfreq, 406 struct notifier_block *nb, 407 unsigned int list) 408 { 409 return 0; 410 } 411 412 static inline int devfreq_unregister_notifier(struct devfreq *devfreq, 413 struct notifier_block *nb, 414 unsigned int list) 415 { 416 return 0; 417 } 418 419 static inline int devm_devfreq_register_notifier(struct device *dev, 420 struct devfreq *devfreq, 421 struct notifier_block *nb, 422 unsigned int list) 423 { 424 return 0; 425 } 426 427 static inline void devm_devfreq_unregister_notifier(struct device *dev, 428 struct devfreq *devfreq, 429 struct notifier_block *nb, 430 unsigned int list) 431 { 432 } 433 434 static inline struct devfreq *devfreq_get_devfreq_by_node(struct device_node *node) 435 { 436 return ERR_PTR(-ENODEV); 437 } 438 439 static inline struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev, 440 const char *phandle_name, int index) 441 { 442 return ERR_PTR(-ENODEV); 443 } 444 445 static inline int devfreq_update_stats(struct devfreq *df) 446 { 447 return -EINVAL; 448 } 449 #endif /* CONFIG_PM_DEVFREQ */ 450 451 #endif /* __LINUX_DEVFREQ_H__ */ 452