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 * @freq_table: current frequency table used by the devfreq driver. 152 * @max_state: count of entry present in the frequency table. 153 * @previous_freq: previously configured frequency value. 154 * @last_status: devfreq user device info, performance statistics 155 * @data: devfreq driver pass to governors, governor should not change it. 156 * @governor_data: private data for governors, devfreq core doesn't touch it. 157 * @user_min_freq_req: PM QoS minimum frequency request from user (via sysfs) 158 * @user_max_freq_req: PM QoS maximum frequency request from user (via sysfs) 159 * @scaling_min_freq: Limit minimum frequency requested by OPP interface 160 * @scaling_max_freq: Limit maximum frequency requested by OPP interface 161 * @stop_polling: devfreq polling status of a device. 162 * @suspend_freq: frequency of a device set during suspend phase. 163 * @resume_freq: frequency of a device set in resume phase. 164 * @suspend_count: suspend requests counter for a device. 165 * @stats: Statistics of devfreq device behavior 166 * @transition_notifier_list: list head of DEVFREQ_TRANSITION_NOTIFIER notifier 167 * @cdev: Cooling device pointer if the devfreq has cooling property 168 * @nb_min: Notifier block for DEV_PM_QOS_MIN_FREQUENCY 169 * @nb_max: Notifier block for DEV_PM_QOS_MAX_FREQUENCY 170 * 171 * This structure stores the devfreq information for a given device. 172 * 173 * Note that when a governor accesses entries in struct devfreq in its 174 * functions except for the context of callbacks defined in struct 175 * devfreq_governor, the governor should protect its access with the 176 * struct mutex lock in struct devfreq. A governor may use this mutex 177 * to protect its own private data in ``void *data`` as well. 178 */ 179 struct devfreq { 180 struct list_head node; 181 182 struct mutex lock; 183 struct device dev; 184 struct devfreq_dev_profile *profile; 185 const struct devfreq_governor *governor; 186 struct opp_table *opp_table; 187 struct notifier_block nb; 188 struct delayed_work work; 189 190 unsigned long *freq_table; 191 unsigned int max_state; 192 193 unsigned long previous_freq; 194 struct devfreq_dev_status last_status; 195 196 void *data; 197 void *governor_data; 198 199 struct dev_pm_qos_request user_min_freq_req; 200 struct dev_pm_qos_request user_max_freq_req; 201 unsigned long scaling_min_freq; 202 unsigned long scaling_max_freq; 203 bool stop_polling; 204 205 unsigned long suspend_freq; 206 unsigned long resume_freq; 207 atomic_t suspend_count; 208 209 /* information for device frequency transitions */ 210 struct devfreq_stats stats; 211 212 struct srcu_notifier_head transition_notifier_list; 213 214 /* Pointer to the cooling device if used for thermal mitigation */ 215 struct thermal_cooling_device *cdev; 216 217 struct notifier_block nb_min; 218 struct notifier_block nb_max; 219 }; 220 221 struct devfreq_freqs { 222 unsigned long old; 223 unsigned long new; 224 }; 225 226 #if defined(CONFIG_PM_DEVFREQ) 227 struct devfreq *devfreq_add_device(struct device *dev, 228 struct devfreq_dev_profile *profile, 229 const char *governor_name, 230 void *data); 231 int devfreq_remove_device(struct devfreq *devfreq); 232 struct devfreq *devm_devfreq_add_device(struct device *dev, 233 struct devfreq_dev_profile *profile, 234 const char *governor_name, 235 void *data); 236 void devm_devfreq_remove_device(struct device *dev, struct devfreq *devfreq); 237 238 /* Supposed to be called by PM callbacks */ 239 int devfreq_suspend_device(struct devfreq *devfreq); 240 int devfreq_resume_device(struct devfreq *devfreq); 241 242 void devfreq_suspend(void); 243 void devfreq_resume(void); 244 245 /* update_devfreq() - Reevaluate the device and configure frequency */ 246 int update_devfreq(struct devfreq *devfreq); 247 248 /* Helper functions for devfreq user device driver with OPP. */ 249 struct dev_pm_opp *devfreq_recommended_opp(struct device *dev, 250 unsigned long *freq, u32 flags); 251 int devfreq_register_opp_notifier(struct device *dev, 252 struct devfreq *devfreq); 253 int devfreq_unregister_opp_notifier(struct device *dev, 254 struct devfreq *devfreq); 255 int devm_devfreq_register_opp_notifier(struct device *dev, 256 struct devfreq *devfreq); 257 void devm_devfreq_unregister_opp_notifier(struct device *dev, 258 struct devfreq *devfreq); 259 int devfreq_register_notifier(struct devfreq *devfreq, 260 struct notifier_block *nb, 261 unsigned int list); 262 int devfreq_unregister_notifier(struct devfreq *devfreq, 263 struct notifier_block *nb, 264 unsigned int list); 265 int devm_devfreq_register_notifier(struct device *dev, 266 struct devfreq *devfreq, 267 struct notifier_block *nb, 268 unsigned int list); 269 void devm_devfreq_unregister_notifier(struct device *dev, 270 struct devfreq *devfreq, 271 struct notifier_block *nb, 272 unsigned int list); 273 struct devfreq *devfreq_get_devfreq_by_node(struct device_node *node); 274 struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev, 275 const char *phandle_name, int index); 276 #endif /* CONFIG_PM_DEVFREQ */ 277 278 /** 279 * struct devfreq_simple_ondemand_data - ``void *data`` fed to struct devfreq 280 * and devfreq_add_device 281 * @upthreshold: If the load is over this value, the frequency jumps. 282 * Specify 0 to use the default. Valid value = 0 to 100. 283 * @downdifferential: If the load is under upthreshold - downdifferential, 284 * the governor may consider slowing the frequency down. 285 * Specify 0 to use the default. Valid value = 0 to 100. 286 * downdifferential < upthreshold must hold. 287 * 288 * If the fed devfreq_simple_ondemand_data pointer is NULL to the governor, 289 * the governor uses the default values. 290 */ 291 struct devfreq_simple_ondemand_data { 292 unsigned int upthreshold; 293 unsigned int downdifferential; 294 }; 295 296 enum devfreq_parent_dev_type { 297 DEVFREQ_PARENT_DEV, 298 CPUFREQ_PARENT_DEV, 299 }; 300 301 /** 302 * struct devfreq_passive_data - ``void *data`` fed to struct devfreq 303 * and devfreq_add_device 304 * @parent: the devfreq instance of parent device. 305 * @get_target_freq: Optional callback, Returns desired operating frequency 306 * for the device using passive governor. That is called 307 * when passive governor should decide the next frequency 308 * by using the new frequency of parent devfreq device 309 * using governors except for passive governor. 310 * If the devfreq device has the specific method to decide 311 * the next frequency, should use this callback. 312 * @parent_type: the parent type of the device. 313 * @this: the devfreq instance of own device. 314 * @nb: the notifier block for DEVFREQ_TRANSITION_NOTIFIER or 315 * CPUFREQ_TRANSITION_NOTIFIER list. 316 * @cpu_data_list: the list of cpu frequency data for all cpufreq_policy. 317 * 318 * The devfreq_passive_data have to set the devfreq instance of parent 319 * device with governors except for the passive governor. But, don't need to 320 * initialize the 'this' and 'nb' field because the devfreq core will handle 321 * them. 322 */ 323 struct devfreq_passive_data { 324 /* Should set the devfreq instance of parent device */ 325 struct devfreq *parent; 326 327 /* Optional callback to decide the next frequency of passvice device */ 328 int (*get_target_freq)(struct devfreq *this, unsigned long *freq); 329 330 /* Should set the type of parent device */ 331 enum devfreq_parent_dev_type parent_type; 332 333 /* For passive governor's internal use. Don't need to set them */ 334 struct devfreq *this; 335 struct notifier_block nb; 336 struct list_head cpu_data_list; 337 }; 338 339 #if !defined(CONFIG_PM_DEVFREQ) 340 static inline struct devfreq *devfreq_add_device(struct device *dev, 341 struct devfreq_dev_profile *profile, 342 const char *governor_name, 343 void *data) 344 { 345 return ERR_PTR(-ENOSYS); 346 } 347 348 static inline int devfreq_remove_device(struct devfreq *devfreq) 349 { 350 return 0; 351 } 352 353 static inline struct devfreq *devm_devfreq_add_device(struct device *dev, 354 struct devfreq_dev_profile *profile, 355 const char *governor_name, 356 void *data) 357 { 358 return ERR_PTR(-ENOSYS); 359 } 360 361 static inline void devm_devfreq_remove_device(struct device *dev, 362 struct devfreq *devfreq) 363 { 364 } 365 366 static inline int devfreq_suspend_device(struct devfreq *devfreq) 367 { 368 return 0; 369 } 370 371 static inline int devfreq_resume_device(struct devfreq *devfreq) 372 { 373 return 0; 374 } 375 376 static inline void devfreq_suspend(void) {} 377 static inline void devfreq_resume(void) {} 378 379 static inline struct dev_pm_opp *devfreq_recommended_opp(struct device *dev, 380 unsigned long *freq, u32 flags) 381 { 382 return ERR_PTR(-EINVAL); 383 } 384 385 static inline int devfreq_register_opp_notifier(struct device *dev, 386 struct devfreq *devfreq) 387 { 388 return -EINVAL; 389 } 390 391 static inline int devfreq_unregister_opp_notifier(struct device *dev, 392 struct devfreq *devfreq) 393 { 394 return -EINVAL; 395 } 396 397 static inline int devm_devfreq_register_opp_notifier(struct device *dev, 398 struct devfreq *devfreq) 399 { 400 return -EINVAL; 401 } 402 403 static inline void devm_devfreq_unregister_opp_notifier(struct device *dev, 404 struct devfreq *devfreq) 405 { 406 } 407 408 static inline int devfreq_register_notifier(struct devfreq *devfreq, 409 struct notifier_block *nb, 410 unsigned int list) 411 { 412 return 0; 413 } 414 415 static inline int devfreq_unregister_notifier(struct devfreq *devfreq, 416 struct notifier_block *nb, 417 unsigned int list) 418 { 419 return 0; 420 } 421 422 static inline int devm_devfreq_register_notifier(struct device *dev, 423 struct devfreq *devfreq, 424 struct notifier_block *nb, 425 unsigned int list) 426 { 427 return 0; 428 } 429 430 static inline void devm_devfreq_unregister_notifier(struct device *dev, 431 struct devfreq *devfreq, 432 struct notifier_block *nb, 433 unsigned int list) 434 { 435 } 436 437 static inline struct devfreq *devfreq_get_devfreq_by_node(struct device_node *node) 438 { 439 return ERR_PTR(-ENODEV); 440 } 441 442 static inline struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev, 443 const char *phandle_name, int index) 444 { 445 return ERR_PTR(-ENODEV); 446 } 447 448 static inline int devfreq_update_stats(struct devfreq *df) 449 { 450 return -EINVAL; 451 } 452 #endif /* CONFIG_PM_DEVFREQ */ 453 454 #endif /* __LINUX_DEVFREQ_H__ */ 455