1 /* 2 * devfreq: Generic Dynamic Voltage and Frequency Scaling (DVFS) Framework 3 * for Non-CPU Devices. 4 * 5 * Copyright (C) 2011 Samsung Electronics 6 * MyungJoo Ham <myungjoo.ham@samsung.com> 7 * 8 * This program is free software; you can redistribute it and/or modify 9 * it under the terms of the GNU General Public License version 2 as 10 * published by the Free Software Foundation. 11 */ 12 13 #ifndef __LINUX_DEVFREQ_H__ 14 #define __LINUX_DEVFREQ_H__ 15 16 #include <linux/device.h> 17 #include <linux/notifier.h> 18 #include <linux/pm_opp.h> 19 20 #define DEVFREQ_NAME_LEN 16 21 22 /* DEVFREQ notifier interface */ 23 #define DEVFREQ_TRANSITION_NOTIFIER (0) 24 25 /* Transition notifiers of DEVFREQ_TRANSITION_NOTIFIER */ 26 #define DEVFREQ_PRECHANGE (0) 27 #define DEVFREQ_POSTCHANGE (1) 28 29 struct devfreq; 30 struct devfreq_governor; 31 32 /** 33 * struct devfreq_dev_status - Data given from devfreq user device to 34 * governors. Represents the performance 35 * statistics. 36 * @total_time: The total time represented by this instance of 37 * devfreq_dev_status 38 * @busy_time: The time that the device was working among the 39 * total_time. 40 * @current_frequency: The operating frequency. 41 * @private_data: An entry not specified by the devfreq framework. 42 * A device and a specific governor may have their 43 * own protocol with private_data. However, because 44 * this is governor-specific, a governor using this 45 * will be only compatible with devices aware of it. 46 */ 47 struct devfreq_dev_status { 48 /* both since the last measure */ 49 unsigned long total_time; 50 unsigned long busy_time; 51 unsigned long current_frequency; 52 void *private_data; 53 }; 54 55 /* 56 * The resulting frequency should be at most this. (this bound is the 57 * least upper bound; thus, the resulting freq should be lower or same) 58 * If the flag is not set, the resulting frequency should be at most the 59 * bound (greatest lower bound) 60 */ 61 #define DEVFREQ_FLAG_LEAST_UPPER_BOUND 0x1 62 63 /** 64 * struct devfreq_dev_profile - Devfreq's user device profile 65 * @initial_freq: The operating frequency when devfreq_add_device() is 66 * called. 67 * @polling_ms: The polling interval in ms. 0 disables polling. 68 * @target: The device should set its operating frequency at 69 * freq or lowest-upper-than-freq value. If freq is 70 * higher than any operable frequency, set maximum. 71 * Before returning, target function should set 72 * freq at the current frequency. 73 * The "flags" parameter's possible values are 74 * explained above with "DEVFREQ_FLAG_*" macros. 75 * @get_dev_status: The device should provide the current performance 76 * status to devfreq. Governors are recommended not to 77 * use this directly. Instead, governors are recommended 78 * to use devfreq_update_stats() along with 79 * devfreq.last_status. 80 * @get_cur_freq: The device should provide the current frequency 81 * at which it is operating. 82 * @exit: An optional callback that is called when devfreq 83 * is removing the devfreq object due to error or 84 * from devfreq_remove_device() call. If the user 85 * has registered devfreq->nb at a notifier-head, 86 * this is the time to unregister it. 87 * @freq_table: Optional list of frequencies to support statistics. 88 * @max_state: The size of freq_table. 89 */ 90 struct devfreq_dev_profile { 91 unsigned long initial_freq; 92 unsigned int polling_ms; 93 94 int (*target)(struct device *dev, unsigned long *freq, u32 flags); 95 int (*get_dev_status)(struct device *dev, 96 struct devfreq_dev_status *stat); 97 int (*get_cur_freq)(struct device *dev, unsigned long *freq); 98 void (*exit)(struct device *dev); 99 100 unsigned long *freq_table; 101 unsigned int max_state; 102 }; 103 104 /** 105 * struct devfreq - Device devfreq structure 106 * @node: list node - contains the devices with devfreq that have been 107 * registered. 108 * @lock: a mutex to protect accessing devfreq. 109 * @dev: device registered by devfreq class. dev.parent is the device 110 * using devfreq. 111 * @profile: device-specific devfreq profile 112 * @governor: method how to choose frequency based on the usage. 113 * @governor_name: devfreq governor name for use with this devfreq 114 * @nb: notifier block used to notify devfreq object that it should 115 * reevaluate operable frequencies. Devfreq users may use 116 * devfreq.nb to the corresponding register notifier call chain. 117 * @work: delayed work for load monitoring. 118 * @previous_freq: previously configured frequency value. 119 * @data: Private data of the governor. The devfreq framework does not 120 * touch this. 121 * @min_freq: Limit minimum frequency requested by user (0: none) 122 * @max_freq: Limit maximum frequency requested by user (0: none) 123 * @stop_polling: devfreq polling status of a device. 124 * @total_trans: Number of devfreq transitions 125 * @trans_table: Statistics of devfreq transitions 126 * @time_in_state: Statistics of devfreq states 127 * @last_stat_updated: The last time stat updated 128 * @transition_notifier_list: list head of DEVFREQ_TRANSITION_NOTIFIER notifier 129 * 130 * This structure stores the devfreq information for a give device. 131 * 132 * Note that when a governor accesses entries in struct devfreq in its 133 * functions except for the context of callbacks defined in struct 134 * devfreq_governor, the governor should protect its access with the 135 * struct mutex lock in struct devfreq. A governor may use this mutex 136 * to protect its own private data in void *data as well. 137 */ 138 struct devfreq { 139 struct list_head node; 140 141 struct mutex lock; 142 struct device dev; 143 struct devfreq_dev_profile *profile; 144 const struct devfreq_governor *governor; 145 char governor_name[DEVFREQ_NAME_LEN]; 146 struct notifier_block nb; 147 struct delayed_work work; 148 149 unsigned long previous_freq; 150 struct devfreq_dev_status last_status; 151 152 void *data; /* private data for governors */ 153 154 unsigned long min_freq; 155 unsigned long max_freq; 156 bool stop_polling; 157 158 /* information for device frequency transition */ 159 unsigned int total_trans; 160 unsigned int *trans_table; 161 unsigned long *time_in_state; 162 unsigned long last_stat_updated; 163 164 struct srcu_notifier_head transition_notifier_list; 165 }; 166 167 struct devfreq_freqs { 168 unsigned long old; 169 unsigned long new; 170 }; 171 172 #if defined(CONFIG_PM_DEVFREQ) 173 extern struct devfreq *devfreq_add_device(struct device *dev, 174 struct devfreq_dev_profile *profile, 175 const char *governor_name, 176 void *data); 177 extern int devfreq_remove_device(struct devfreq *devfreq); 178 extern struct devfreq *devm_devfreq_add_device(struct device *dev, 179 struct devfreq_dev_profile *profile, 180 const char *governor_name, 181 void *data); 182 extern void devm_devfreq_remove_device(struct device *dev, 183 struct devfreq *devfreq); 184 185 /* Supposed to be called by PM callbacks */ 186 extern int devfreq_suspend_device(struct devfreq *devfreq); 187 extern int devfreq_resume_device(struct devfreq *devfreq); 188 189 /* Helper functions for devfreq user device driver with OPP. */ 190 extern struct dev_pm_opp *devfreq_recommended_opp(struct device *dev, 191 unsigned long *freq, u32 flags); 192 extern int devfreq_register_opp_notifier(struct device *dev, 193 struct devfreq *devfreq); 194 extern int devfreq_unregister_opp_notifier(struct device *dev, 195 struct devfreq *devfreq); 196 extern int devm_devfreq_register_opp_notifier(struct device *dev, 197 struct devfreq *devfreq); 198 extern void devm_devfreq_unregister_opp_notifier(struct device *dev, 199 struct devfreq *devfreq); 200 extern int devfreq_register_notifier(struct devfreq *devfreq, 201 struct notifier_block *nb, 202 unsigned int list); 203 extern int devfreq_unregister_notifier(struct devfreq *devfreq, 204 struct notifier_block *nb, 205 unsigned int list); 206 extern int devm_devfreq_register_notifier(struct device *dev, 207 struct devfreq *devfreq, 208 struct notifier_block *nb, 209 unsigned int list); 210 extern void devm_devfreq_unregister_notifier(struct device *dev, 211 struct devfreq *devfreq, 212 struct notifier_block *nb, 213 unsigned int list); 214 extern struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev, 215 int index); 216 217 /** 218 * devfreq_update_stats() - update the last_status pointer in struct devfreq 219 * @df: the devfreq instance whose status needs updating 220 * 221 * Governors are recommended to use this function along with last_status, 222 * which allows other entities to reuse the last_status without affecting 223 * the values fetched later by governors. 224 */ 225 static inline int devfreq_update_stats(struct devfreq *df) 226 { 227 return df->profile->get_dev_status(df->dev.parent, &df->last_status); 228 } 229 230 #if IS_ENABLED(CONFIG_DEVFREQ_GOV_SIMPLE_ONDEMAND) 231 /** 232 * struct devfreq_simple_ondemand_data - void *data fed to struct devfreq 233 * and devfreq_add_device 234 * @upthreshold: If the load is over this value, the frequency jumps. 235 * Specify 0 to use the default. Valid value = 0 to 100. 236 * @downdifferential: If the load is under upthreshold - downdifferential, 237 * the governor may consider slowing the frequency down. 238 * Specify 0 to use the default. Valid value = 0 to 100. 239 * downdifferential < upthreshold must hold. 240 * 241 * If the fed devfreq_simple_ondemand_data pointer is NULL to the governor, 242 * the governor uses the default values. 243 */ 244 struct devfreq_simple_ondemand_data { 245 unsigned int upthreshold; 246 unsigned int downdifferential; 247 }; 248 #endif 249 250 #if IS_ENABLED(CONFIG_DEVFREQ_GOV_PASSIVE) 251 /** 252 * struct devfreq_passive_data - void *data fed to struct devfreq 253 * and devfreq_add_device 254 * @parent: the devfreq instance of parent device. 255 * @get_target_freq: Optional callback, Returns desired operating frequency 256 * for the device using passive governor. That is called 257 * when passive governor should decide the next frequency 258 * by using the new frequency of parent devfreq device 259 * using governors except for passive governor. 260 * If the devfreq device has the specific method to decide 261 * the next frequency, should use this callback. 262 * @this: the devfreq instance of own device. 263 * @nb: the notifier block for DEVFREQ_TRANSITION_NOTIFIER list 264 * 265 * The devfreq_passive_data have to set the devfreq instance of parent 266 * device with governors except for the passive governor. But, don't need to 267 * initialize the 'this' and 'nb' field because the devfreq core will handle 268 * them. 269 */ 270 struct devfreq_passive_data { 271 /* Should set the devfreq instance of parent device */ 272 struct devfreq *parent; 273 274 /* Optional callback to decide the next frequency of passvice device */ 275 int (*get_target_freq)(struct devfreq *this, unsigned long *freq); 276 277 /* For passive governor's internal use. Don't need to set them */ 278 struct devfreq *this; 279 struct notifier_block nb; 280 }; 281 #endif 282 283 #else /* !CONFIG_PM_DEVFREQ */ 284 static inline struct devfreq *devfreq_add_device(struct device *dev, 285 struct devfreq_dev_profile *profile, 286 const char *governor_name, 287 void *data) 288 { 289 return ERR_PTR(-ENOSYS); 290 } 291 292 static inline int devfreq_remove_device(struct devfreq *devfreq) 293 { 294 return 0; 295 } 296 297 static inline struct devfreq *devm_devfreq_add_device(struct device *dev, 298 struct devfreq_dev_profile *profile, 299 const char *governor_name, 300 void *data) 301 { 302 return ERR_PTR(-ENOSYS); 303 } 304 305 static inline void devm_devfreq_remove_device(struct device *dev, 306 struct devfreq *devfreq) 307 { 308 } 309 310 static inline int devfreq_suspend_device(struct devfreq *devfreq) 311 { 312 return 0; 313 } 314 315 static inline int devfreq_resume_device(struct devfreq *devfreq) 316 { 317 return 0; 318 } 319 320 static inline struct dev_pm_opp *devfreq_recommended_opp(struct device *dev, 321 unsigned long *freq, u32 flags) 322 { 323 return ERR_PTR(-EINVAL); 324 } 325 326 static inline int devfreq_register_opp_notifier(struct device *dev, 327 struct devfreq *devfreq) 328 { 329 return -EINVAL; 330 } 331 332 static inline int devfreq_unregister_opp_notifier(struct device *dev, 333 struct devfreq *devfreq) 334 { 335 return -EINVAL; 336 } 337 338 static inline int devm_devfreq_register_opp_notifier(struct device *dev, 339 struct devfreq *devfreq) 340 { 341 return -EINVAL; 342 } 343 344 static inline void devm_devfreq_unregister_opp_notifier(struct device *dev, 345 struct devfreq *devfreq) 346 { 347 } 348 349 static inline int devfreq_register_notifier(struct devfreq *devfreq, 350 struct notifier_block *nb, 351 unsigned int list) 352 { 353 return 0; 354 } 355 356 static inline int devfreq_unregister_notifier(struct devfreq *devfreq, 357 struct notifier_block *nb, 358 unsigned int list) 359 { 360 return 0; 361 } 362 363 static inline int devm_devfreq_register_notifier(struct device *dev, 364 struct devfreq *devfreq, 365 struct notifier_block *nb, 366 unsigned int list) 367 { 368 return 0; 369 } 370 371 static inline void devm_devfreq_unregister_notifier(struct device *dev, 372 struct devfreq *devfreq, 373 struct notifier_block *nb, 374 unsigned int list) 375 { 376 } 377 378 static inline struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev, 379 int index) 380 { 381 return ERR_PTR(-ENODEV); 382 } 383 384 static inline int devfreq_update_stats(struct devfreq *df) 385 { 386 return -EINVAL; 387 } 388 #endif /* CONFIG_PM_DEVFREQ */ 389 390 #endif /* __LINUX_DEVFREQ_H__ */ 391