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 - Device devfreq structure 112 * @node: list node - contains the devices with devfreq that have been 113 * registered. 114 * @lock: a mutex to protect accessing devfreq. 115 * @dev: device registered by devfreq class. dev.parent is the device 116 * using devfreq. 117 * @profile: device-specific devfreq profile 118 * @governor: method how to choose frequency based on the usage. 119 * @governor_name: devfreq governor name for use with this devfreq 120 * @nb: notifier block used to notify devfreq object that it should 121 * reevaluate operable frequencies. Devfreq users may use 122 * devfreq.nb to the corresponding register notifier call chain. 123 * @work: delayed work for load monitoring. 124 * @previous_freq: previously configured frequency value. 125 * @data: Private data of the governor. The devfreq framework does not 126 * touch this. 127 * @user_min_freq_req: PM QoS minimum frequency request from user (via sysfs) 128 * @user_max_freq_req: PM QoS maximum frequency request from user (via sysfs) 129 * @scaling_min_freq: Limit minimum frequency requested by OPP interface 130 * @scaling_max_freq: Limit maximum frequency requested by OPP interface 131 * @stop_polling: devfreq polling status of a device. 132 * @suspend_freq: frequency of a device set during suspend phase. 133 * @resume_freq: frequency of a device set in resume phase. 134 * @suspend_count: suspend requests counter for a device. 135 * @total_trans: Number of devfreq transitions 136 * @trans_table: Statistics of devfreq transitions 137 * @time_in_state: Statistics of devfreq states 138 * @last_stat_updated: The last time stat updated 139 * @transition_notifier_list: list head of DEVFREQ_TRANSITION_NOTIFIER notifier 140 * @nb_min: Notifier block for DEV_PM_QOS_MIN_FREQUENCY 141 * @nb_max: Notifier block for DEV_PM_QOS_MAX_FREQUENCY 142 * 143 * This structure stores the devfreq information for a give device. 144 * 145 * Note that when a governor accesses entries in struct devfreq in its 146 * functions except for the context of callbacks defined in struct 147 * devfreq_governor, the governor should protect its access with the 148 * struct mutex lock in struct devfreq. A governor may use this mutex 149 * to protect its own private data in void *data as well. 150 */ 151 struct devfreq { 152 struct list_head node; 153 154 struct mutex lock; 155 struct device dev; 156 struct devfreq_dev_profile *profile; 157 const struct devfreq_governor *governor; 158 char governor_name[DEVFREQ_NAME_LEN]; 159 struct notifier_block nb; 160 struct delayed_work work; 161 162 unsigned long previous_freq; 163 struct devfreq_dev_status last_status; 164 165 void *data; /* private data for governors */ 166 167 struct dev_pm_qos_request user_min_freq_req; 168 struct dev_pm_qos_request user_max_freq_req; 169 unsigned long scaling_min_freq; 170 unsigned long scaling_max_freq; 171 bool stop_polling; 172 173 unsigned long suspend_freq; 174 unsigned long resume_freq; 175 atomic_t suspend_count; 176 177 /* information for device frequency transition */ 178 unsigned int total_trans; 179 unsigned int *trans_table; 180 unsigned long *time_in_state; 181 unsigned long last_stat_updated; 182 183 struct srcu_notifier_head transition_notifier_list; 184 185 struct notifier_block nb_min; 186 struct notifier_block nb_max; 187 }; 188 189 struct devfreq_freqs { 190 unsigned long old; 191 unsigned long new; 192 }; 193 194 #if defined(CONFIG_PM_DEVFREQ) 195 extern struct devfreq *devfreq_add_device(struct device *dev, 196 struct devfreq_dev_profile *profile, 197 const char *governor_name, 198 void *data); 199 extern int devfreq_remove_device(struct devfreq *devfreq); 200 extern struct devfreq *devm_devfreq_add_device(struct device *dev, 201 struct devfreq_dev_profile *profile, 202 const char *governor_name, 203 void *data); 204 extern void devm_devfreq_remove_device(struct device *dev, 205 struct devfreq *devfreq); 206 207 /* Supposed to be called by PM callbacks */ 208 extern int devfreq_suspend_device(struct devfreq *devfreq); 209 extern int devfreq_resume_device(struct devfreq *devfreq); 210 211 extern void devfreq_suspend(void); 212 extern void devfreq_resume(void); 213 214 /** 215 * update_devfreq() - Reevaluate the device and configure frequency 216 * @devfreq: the devfreq device 217 * 218 * Note: devfreq->lock must be held 219 */ 220 extern int update_devfreq(struct devfreq *devfreq); 221 222 /* Helper functions for devfreq user device driver with OPP. */ 223 extern struct dev_pm_opp *devfreq_recommended_opp(struct device *dev, 224 unsigned long *freq, u32 flags); 225 extern int devfreq_register_opp_notifier(struct device *dev, 226 struct devfreq *devfreq); 227 extern int devfreq_unregister_opp_notifier(struct device *dev, 228 struct devfreq *devfreq); 229 extern int devm_devfreq_register_opp_notifier(struct device *dev, 230 struct devfreq *devfreq); 231 extern void devm_devfreq_unregister_opp_notifier(struct device *dev, 232 struct devfreq *devfreq); 233 extern int devfreq_register_notifier(struct devfreq *devfreq, 234 struct notifier_block *nb, 235 unsigned int list); 236 extern int devfreq_unregister_notifier(struct devfreq *devfreq, 237 struct notifier_block *nb, 238 unsigned int list); 239 extern int devm_devfreq_register_notifier(struct device *dev, 240 struct devfreq *devfreq, 241 struct notifier_block *nb, 242 unsigned int list); 243 extern void devm_devfreq_unregister_notifier(struct device *dev, 244 struct devfreq *devfreq, 245 struct notifier_block *nb, 246 unsigned int list); 247 extern struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev, 248 int index); 249 250 #if IS_ENABLED(CONFIG_DEVFREQ_GOV_SIMPLE_ONDEMAND) 251 /** 252 * struct devfreq_simple_ondemand_data - void *data fed to struct devfreq 253 * and devfreq_add_device 254 * @upthreshold: If the load is over this value, the frequency jumps. 255 * Specify 0 to use the default. Valid value = 0 to 100. 256 * @downdifferential: If the load is under upthreshold - downdifferential, 257 * the governor may consider slowing the frequency down. 258 * Specify 0 to use the default. Valid value = 0 to 100. 259 * downdifferential < upthreshold must hold. 260 * 261 * If the fed devfreq_simple_ondemand_data pointer is NULL to the governor, 262 * the governor uses the default values. 263 */ 264 struct devfreq_simple_ondemand_data { 265 unsigned int upthreshold; 266 unsigned int downdifferential; 267 }; 268 #endif 269 270 #if IS_ENABLED(CONFIG_DEVFREQ_GOV_PASSIVE) 271 /** 272 * struct devfreq_passive_data - void *data fed to struct devfreq 273 * and devfreq_add_device 274 * @parent: the devfreq instance of parent device. 275 * @get_target_freq: Optional callback, Returns desired operating frequency 276 * for the device using passive governor. That is called 277 * when passive governor should decide the next frequency 278 * by using the new frequency of parent devfreq device 279 * using governors except for passive governor. 280 * If the devfreq device has the specific method to decide 281 * the next frequency, should use this callback. 282 * @this: the devfreq instance of own device. 283 * @nb: the notifier block for DEVFREQ_TRANSITION_NOTIFIER list 284 * 285 * The devfreq_passive_data have to set the devfreq instance of parent 286 * device with governors except for the passive governor. But, don't need to 287 * initialize the 'this' and 'nb' field because the devfreq core will handle 288 * them. 289 */ 290 struct devfreq_passive_data { 291 /* Should set the devfreq instance of parent device */ 292 struct devfreq *parent; 293 294 /* Optional callback to decide the next frequency of passvice device */ 295 int (*get_target_freq)(struct devfreq *this, unsigned long *freq); 296 297 /* For passive governor's internal use. Don't need to set them */ 298 struct devfreq *this; 299 struct notifier_block nb; 300 }; 301 #endif 302 303 #else /* !CONFIG_PM_DEVFREQ */ 304 static inline struct devfreq *devfreq_add_device(struct device *dev, 305 struct devfreq_dev_profile *profile, 306 const char *governor_name, 307 void *data) 308 { 309 return ERR_PTR(-ENOSYS); 310 } 311 312 static inline int devfreq_remove_device(struct devfreq *devfreq) 313 { 314 return 0; 315 } 316 317 static inline struct devfreq *devm_devfreq_add_device(struct device *dev, 318 struct devfreq_dev_profile *profile, 319 const char *governor_name, 320 void *data) 321 { 322 return ERR_PTR(-ENOSYS); 323 } 324 325 static inline void devm_devfreq_remove_device(struct device *dev, 326 struct devfreq *devfreq) 327 { 328 } 329 330 static inline int devfreq_suspend_device(struct devfreq *devfreq) 331 { 332 return 0; 333 } 334 335 static inline int devfreq_resume_device(struct devfreq *devfreq) 336 { 337 return 0; 338 } 339 340 static inline void devfreq_suspend(void) {} 341 static inline void devfreq_resume(void) {} 342 343 static inline struct dev_pm_opp *devfreq_recommended_opp(struct device *dev, 344 unsigned long *freq, u32 flags) 345 { 346 return ERR_PTR(-EINVAL); 347 } 348 349 static inline int devfreq_register_opp_notifier(struct device *dev, 350 struct devfreq *devfreq) 351 { 352 return -EINVAL; 353 } 354 355 static inline int devfreq_unregister_opp_notifier(struct device *dev, 356 struct devfreq *devfreq) 357 { 358 return -EINVAL; 359 } 360 361 static inline int devm_devfreq_register_opp_notifier(struct device *dev, 362 struct devfreq *devfreq) 363 { 364 return -EINVAL; 365 } 366 367 static inline void devm_devfreq_unregister_opp_notifier(struct device *dev, 368 struct devfreq *devfreq) 369 { 370 } 371 372 static inline int devfreq_register_notifier(struct devfreq *devfreq, 373 struct notifier_block *nb, 374 unsigned int list) 375 { 376 return 0; 377 } 378 379 static inline int devfreq_unregister_notifier(struct devfreq *devfreq, 380 struct notifier_block *nb, 381 unsigned int list) 382 { 383 return 0; 384 } 385 386 static inline int devm_devfreq_register_notifier(struct device *dev, 387 struct devfreq *devfreq, 388 struct notifier_block *nb, 389 unsigned int list) 390 { 391 return 0; 392 } 393 394 static inline void devm_devfreq_unregister_notifier(struct device *dev, 395 struct devfreq *devfreq, 396 struct notifier_block *nb, 397 unsigned int list) 398 { 399 } 400 401 static inline struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev, 402 int index) 403 { 404 return ERR_PTR(-ENODEV); 405 } 406 407 static inline int devfreq_update_stats(struct devfreq *df) 408 { 409 return -EINVAL; 410 } 411 #endif /* CONFIG_PM_DEVFREQ */ 412 413 #endif /* __LINUX_DEVFREQ_H__ */ 414