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 struct devfreq; 35 struct devfreq_governor; 36 37 /** 38 * struct devfreq_dev_status - Data given from devfreq user device to 39 * governors. Represents the performance 40 * statistics. 41 * @total_time: The total time represented by this instance of 42 * devfreq_dev_status 43 * @busy_time: The time that the device was working among the 44 * total_time. 45 * @current_frequency: The operating frequency. 46 * @private_data: An entry not specified by the devfreq framework. 47 * A device and a specific governor may have their 48 * own protocol with private_data. However, because 49 * this is governor-specific, a governor using this 50 * will be only compatible with devices aware of it. 51 */ 52 struct devfreq_dev_status { 53 /* both since the last measure */ 54 unsigned long total_time; 55 unsigned long busy_time; 56 unsigned long current_frequency; 57 void *private_data; 58 }; 59 60 /* 61 * The resulting frequency should be at most this. (this bound is the 62 * least upper bound; thus, the resulting freq should be lower or same) 63 * If the flag is not set, the resulting frequency should be at most the 64 * bound (greatest lower bound) 65 */ 66 #define DEVFREQ_FLAG_LEAST_UPPER_BOUND 0x1 67 68 /** 69 * struct devfreq_dev_profile - Devfreq's user device profile 70 * @initial_freq: The operating frequency when devfreq_add_device() is 71 * called. 72 * @polling_ms: The polling interval in ms. 0 disables polling. 73 * @target: The device should set its operating frequency at 74 * freq or lowest-upper-than-freq value. If freq is 75 * higher than any operable frequency, set maximum. 76 * Before returning, target function should set 77 * freq at the current frequency. 78 * The "flags" parameter's possible values are 79 * explained above with "DEVFREQ_FLAG_*" macros. 80 * @get_dev_status: The device should provide the current performance 81 * status to devfreq. Governors are recommended not to 82 * use this directly. Instead, governors are recommended 83 * to use devfreq_update_stats() along with 84 * devfreq.last_status. 85 * @get_cur_freq: The device should provide the current frequency 86 * at which it is operating. 87 * @exit: An optional callback that is called when devfreq 88 * is removing the devfreq object due to error or 89 * from devfreq_remove_device() call. If the user 90 * has registered devfreq->nb at a notifier-head, 91 * this is the time to unregister it. 92 * @freq_table: Optional list of frequencies to support statistics 93 * and freq_table must be generated in ascending order. 94 * @max_state: The size of freq_table. 95 */ 96 struct devfreq_dev_profile { 97 unsigned long initial_freq; 98 unsigned int polling_ms; 99 100 int (*target)(struct device *dev, unsigned long *freq, u32 flags); 101 int (*get_dev_status)(struct device *dev, 102 struct devfreq_dev_status *stat); 103 int (*get_cur_freq)(struct device *dev, unsigned long *freq); 104 void (*exit)(struct device *dev); 105 106 unsigned long *freq_table; 107 unsigned int max_state; 108 }; 109 110 /** 111 * struct devfreq_stats - Statistics of devfreq device behavior 112 * @total_trans: Number of devfreq transitions. 113 * @trans_table: Statistics of devfreq transitions. 114 * @time_in_state: Statistics of devfreq states. 115 * @last_update: The last time stats were updated. 116 */ 117 struct devfreq_stats { 118 unsigned int total_trans; 119 unsigned int *trans_table; 120 u64 *time_in_state; 121 u64 last_update; 122 }; 123 124 /** 125 * struct devfreq - Device devfreq structure 126 * @node: list node - contains the devices with devfreq that have been 127 * registered. 128 * @lock: a mutex to protect accessing devfreq. 129 * @dev: device registered by devfreq class. dev.parent is the device 130 * using devfreq. 131 * @profile: device-specific devfreq profile 132 * @governor: method how to choose frequency based on the usage. 133 * @governor_name: devfreq governor name for use with this devfreq 134 * @nb: notifier block used to notify devfreq object that it should 135 * reevaluate operable frequencies. Devfreq users may use 136 * devfreq.nb to the corresponding register notifier call chain. 137 * @work: delayed work for load monitoring. 138 * @previous_freq: previously configured frequency value. 139 * @last_status: devfreq user device info, performance statistics 140 * @data: Private data of the governor. The devfreq framework does not 141 * touch this. 142 * @user_min_freq_req: PM QoS minimum frequency request from user (via sysfs) 143 * @user_max_freq_req: PM QoS maximum frequency request from user (via sysfs) 144 * @scaling_min_freq: Limit minimum frequency requested by OPP interface 145 * @scaling_max_freq: Limit maximum frequency requested by OPP interface 146 * @stop_polling: devfreq polling status of a device. 147 * @suspend_freq: frequency of a device set during suspend phase. 148 * @resume_freq: frequency of a device set in resume phase. 149 * @suspend_count: suspend requests counter for a device. 150 * @stats: Statistics of devfreq device behavior 151 * @transition_notifier_list: list head of DEVFREQ_TRANSITION_NOTIFIER notifier 152 * @nb_min: Notifier block for DEV_PM_QOS_MIN_FREQUENCY 153 * @nb_max: Notifier block for DEV_PM_QOS_MAX_FREQUENCY 154 * 155 * This structure stores the devfreq information for a given device. 156 * 157 * Note that when a governor accesses entries in struct devfreq in its 158 * functions except for the context of callbacks defined in struct 159 * devfreq_governor, the governor should protect its access with the 160 * struct mutex lock in struct devfreq. A governor may use this mutex 161 * to protect its own private data in void *data as well. 162 */ 163 struct devfreq { 164 struct list_head node; 165 166 struct mutex lock; 167 struct device dev; 168 struct devfreq_dev_profile *profile; 169 const struct devfreq_governor *governor; 170 char governor_name[DEVFREQ_NAME_LEN]; 171 struct notifier_block nb; 172 struct delayed_work work; 173 174 unsigned long previous_freq; 175 struct devfreq_dev_status last_status; 176 177 void *data; /* private data for governors */ 178 179 struct dev_pm_qos_request user_min_freq_req; 180 struct dev_pm_qos_request user_max_freq_req; 181 unsigned long scaling_min_freq; 182 unsigned long scaling_max_freq; 183 bool stop_polling; 184 185 unsigned long suspend_freq; 186 unsigned long resume_freq; 187 atomic_t suspend_count; 188 189 /* information for device frequency transitions */ 190 struct devfreq_stats stats; 191 192 struct srcu_notifier_head transition_notifier_list; 193 194 struct notifier_block nb_min; 195 struct notifier_block nb_max; 196 }; 197 198 struct devfreq_freqs { 199 unsigned long old; 200 unsigned long new; 201 }; 202 203 #if defined(CONFIG_PM_DEVFREQ) 204 extern struct devfreq *devfreq_add_device(struct device *dev, 205 struct devfreq_dev_profile *profile, 206 const char *governor_name, 207 void *data); 208 extern int devfreq_remove_device(struct devfreq *devfreq); 209 extern struct devfreq *devm_devfreq_add_device(struct device *dev, 210 struct devfreq_dev_profile *profile, 211 const char *governor_name, 212 void *data); 213 extern void devm_devfreq_remove_device(struct device *dev, 214 struct devfreq *devfreq); 215 216 /* Supposed to be called by PM callbacks */ 217 extern int devfreq_suspend_device(struct devfreq *devfreq); 218 extern int devfreq_resume_device(struct devfreq *devfreq); 219 220 extern void devfreq_suspend(void); 221 extern void devfreq_resume(void); 222 223 /** 224 * update_devfreq() - Reevaluate the device and configure frequency 225 * @devfreq: the devfreq device 226 * 227 * Note: devfreq->lock must be held 228 */ 229 extern int update_devfreq(struct devfreq *devfreq); 230 231 /* Helper functions for devfreq user device driver with OPP. */ 232 extern struct dev_pm_opp *devfreq_recommended_opp(struct device *dev, 233 unsigned long *freq, u32 flags); 234 extern int devfreq_register_opp_notifier(struct device *dev, 235 struct devfreq *devfreq); 236 extern int devfreq_unregister_opp_notifier(struct device *dev, 237 struct devfreq *devfreq); 238 extern int devm_devfreq_register_opp_notifier(struct device *dev, 239 struct devfreq *devfreq); 240 extern void devm_devfreq_unregister_opp_notifier(struct device *dev, 241 struct devfreq *devfreq); 242 extern int devfreq_register_notifier(struct devfreq *devfreq, 243 struct notifier_block *nb, 244 unsigned int list); 245 extern int devfreq_unregister_notifier(struct devfreq *devfreq, 246 struct notifier_block *nb, 247 unsigned int list); 248 extern int devm_devfreq_register_notifier(struct device *dev, 249 struct devfreq *devfreq, 250 struct notifier_block *nb, 251 unsigned int list); 252 extern void devm_devfreq_unregister_notifier(struct device *dev, 253 struct devfreq *devfreq, 254 struct notifier_block *nb, 255 unsigned int list); 256 extern struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev, 257 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_phandle(struct device *dev, 411 int index) 412 { 413 return ERR_PTR(-ENODEV); 414 } 415 416 static inline int devfreq_update_stats(struct devfreq *df) 417 { 418 return -EINVAL; 419 } 420 #endif /* CONFIG_PM_DEVFREQ */ 421 422 #endif /* __LINUX_DEVFREQ_H__ */ 423