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 governor name */ 23 #define DEVFREQ_GOV_SIMPLE_ONDEMAND "simple_ondemand" 24 #define DEVFREQ_GOV_PERFORMANCE "performance" 25 #define DEVFREQ_GOV_POWERSAVE "powersave" 26 #define DEVFREQ_GOV_USERSPACE "userspace" 27 #define DEVFREQ_GOV_PASSIVE "passive" 28 29 /* DEVFREQ notifier interface */ 30 #define DEVFREQ_TRANSITION_NOTIFIER (0) 31 32 /* Transition notifiers of DEVFREQ_TRANSITION_NOTIFIER */ 33 #define DEVFREQ_PRECHANGE (0) 34 #define DEVFREQ_POSTCHANGE (1) 35 36 struct devfreq; 37 struct devfreq_governor; 38 39 /** 40 * struct devfreq_dev_status - Data given from devfreq user device to 41 * governors. Represents the performance 42 * statistics. 43 * @total_time: The total time represented by this instance of 44 * devfreq_dev_status 45 * @busy_time: The time that the device was working among the 46 * total_time. 47 * @current_frequency: The operating frequency. 48 * @private_data: An entry not specified by the devfreq framework. 49 * A device and a specific governor may have their 50 * own protocol with private_data. However, because 51 * this is governor-specific, a governor using this 52 * will be only compatible with devices aware of it. 53 */ 54 struct devfreq_dev_status { 55 /* both since the last measure */ 56 unsigned long total_time; 57 unsigned long busy_time; 58 unsigned long current_frequency; 59 void *private_data; 60 }; 61 62 /* 63 * The resulting frequency should be at most this. (this bound is the 64 * least upper bound; thus, the resulting freq should be lower or same) 65 * If the flag is not set, the resulting frequency should be at most the 66 * bound (greatest lower bound) 67 */ 68 #define DEVFREQ_FLAG_LEAST_UPPER_BOUND 0x1 69 70 /** 71 * struct devfreq_dev_profile - Devfreq's user device profile 72 * @initial_freq: The operating frequency when devfreq_add_device() is 73 * called. 74 * @polling_ms: The polling interval in ms. 0 disables polling. 75 * @target: The device should set its operating frequency at 76 * freq or lowest-upper-than-freq value. If freq is 77 * higher than any operable frequency, set maximum. 78 * Before returning, target function should set 79 * freq at the current frequency. 80 * The "flags" parameter's possible values are 81 * explained above with "DEVFREQ_FLAG_*" macros. 82 * @get_dev_status: The device should provide the current performance 83 * status to devfreq. Governors are recommended not to 84 * use this directly. Instead, governors are recommended 85 * to use devfreq_update_stats() along with 86 * devfreq.last_status. 87 * @get_cur_freq: The device should provide the current frequency 88 * at which it is operating. 89 * @exit: An optional callback that is called when devfreq 90 * is removing the devfreq object due to error or 91 * from devfreq_remove_device() call. If the user 92 * has registered devfreq->nb at a notifier-head, 93 * this is the time to unregister it. 94 * @freq_table: Optional list of frequencies to support statistics 95 * and freq_table must be generated in ascending order. 96 * @max_state: The size of freq_table. 97 */ 98 struct devfreq_dev_profile { 99 unsigned long initial_freq; 100 unsigned int polling_ms; 101 102 int (*target)(struct device *dev, unsigned long *freq, u32 flags); 103 int (*get_dev_status)(struct device *dev, 104 struct devfreq_dev_status *stat); 105 int (*get_cur_freq)(struct device *dev, unsigned long *freq); 106 void (*exit)(struct device *dev); 107 108 unsigned long *freq_table; 109 unsigned int max_state; 110 }; 111 112 /** 113 * struct devfreq - Device devfreq structure 114 * @node: list node - contains the devices with devfreq that have been 115 * registered. 116 * @lock: a mutex to protect accessing devfreq. 117 * @dev: device registered by devfreq class. dev.parent is the device 118 * using devfreq. 119 * @profile: device-specific devfreq profile 120 * @governor: method how to choose frequency based on the usage. 121 * @governor_name: devfreq governor name for use with this devfreq 122 * @nb: notifier block used to notify devfreq object that it should 123 * reevaluate operable frequencies. Devfreq users may use 124 * devfreq.nb to the corresponding register notifier call chain. 125 * @work: delayed work for load monitoring. 126 * @previous_freq: previously configured frequency value. 127 * @data: Private data of the governor. The devfreq framework does not 128 * touch this. 129 * @min_freq: Limit minimum frequency requested by user (0: none) 130 * @max_freq: Limit maximum frequency requested by user (0: none) 131 * @scaling_min_freq: Limit minimum frequency requested by OPP interface 132 * @scaling_max_freq: Limit maximum frequency requested by OPP interface 133 * @stop_polling: devfreq polling status of a device. 134 * @total_trans: Number of devfreq transitions 135 * @trans_table: Statistics of devfreq transitions 136 * @time_in_state: Statistics of devfreq states 137 * @last_stat_updated: The last time stat updated 138 * @transition_notifier_list: list head of DEVFREQ_TRANSITION_NOTIFIER notifier 139 * 140 * This structure stores the devfreq information for a give device. 141 * 142 * Note that when a governor accesses entries in struct devfreq in its 143 * functions except for the context of callbacks defined in struct 144 * devfreq_governor, the governor should protect its access with the 145 * struct mutex lock in struct devfreq. A governor may use this mutex 146 * to protect its own private data in void *data as well. 147 */ 148 struct devfreq { 149 struct list_head node; 150 151 struct mutex lock; 152 struct device dev; 153 struct devfreq_dev_profile *profile; 154 const struct devfreq_governor *governor; 155 char governor_name[DEVFREQ_NAME_LEN]; 156 struct notifier_block nb; 157 struct delayed_work work; 158 159 unsigned long previous_freq; 160 struct devfreq_dev_status last_status; 161 162 void *data; /* private data for governors */ 163 164 unsigned long min_freq; 165 unsigned long max_freq; 166 unsigned long scaling_min_freq; 167 unsigned long scaling_max_freq; 168 bool stop_polling; 169 170 /* information for device frequency transition */ 171 unsigned int total_trans; 172 unsigned int *trans_table; 173 unsigned long *time_in_state; 174 unsigned long last_stat_updated; 175 176 struct srcu_notifier_head transition_notifier_list; 177 }; 178 179 struct devfreq_freqs { 180 unsigned long old; 181 unsigned long new; 182 }; 183 184 #if defined(CONFIG_PM_DEVFREQ) 185 extern struct devfreq *devfreq_add_device(struct device *dev, 186 struct devfreq_dev_profile *profile, 187 const char *governor_name, 188 void *data); 189 extern int devfreq_remove_device(struct devfreq *devfreq); 190 extern struct devfreq *devm_devfreq_add_device(struct device *dev, 191 struct devfreq_dev_profile *profile, 192 const char *governor_name, 193 void *data); 194 extern void devm_devfreq_remove_device(struct device *dev, 195 struct devfreq *devfreq); 196 197 /* Supposed to be called by PM callbacks */ 198 extern int devfreq_suspend_device(struct devfreq *devfreq); 199 extern int devfreq_resume_device(struct devfreq *devfreq); 200 201 /** 202 * update_devfreq() - Reevaluate the device and configure frequency 203 * @devfreq: the devfreq device 204 * 205 * Note: devfreq->lock must be held 206 */ 207 extern int update_devfreq(struct devfreq *devfreq); 208 209 /* Helper functions for devfreq user device driver with OPP. */ 210 extern struct dev_pm_opp *devfreq_recommended_opp(struct device *dev, 211 unsigned long *freq, u32 flags); 212 extern int devfreq_register_opp_notifier(struct device *dev, 213 struct devfreq *devfreq); 214 extern int devfreq_unregister_opp_notifier(struct device *dev, 215 struct devfreq *devfreq); 216 extern int devm_devfreq_register_opp_notifier(struct device *dev, 217 struct devfreq *devfreq); 218 extern void devm_devfreq_unregister_opp_notifier(struct device *dev, 219 struct devfreq *devfreq); 220 extern int devfreq_register_notifier(struct devfreq *devfreq, 221 struct notifier_block *nb, 222 unsigned int list); 223 extern int devfreq_unregister_notifier(struct devfreq *devfreq, 224 struct notifier_block *nb, 225 unsigned int list); 226 extern int devm_devfreq_register_notifier(struct device *dev, 227 struct devfreq *devfreq, 228 struct notifier_block *nb, 229 unsigned int list); 230 extern void devm_devfreq_unregister_notifier(struct device *dev, 231 struct devfreq *devfreq, 232 struct notifier_block *nb, 233 unsigned int list); 234 extern struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev, 235 int index); 236 237 #if IS_ENABLED(CONFIG_DEVFREQ_GOV_SIMPLE_ONDEMAND) 238 /** 239 * struct devfreq_simple_ondemand_data - void *data fed to struct devfreq 240 * and devfreq_add_device 241 * @upthreshold: If the load is over this value, the frequency jumps. 242 * Specify 0 to use the default. Valid value = 0 to 100. 243 * @downdifferential: If the load is under upthreshold - downdifferential, 244 * the governor may consider slowing the frequency down. 245 * Specify 0 to use the default. Valid value = 0 to 100. 246 * downdifferential < upthreshold must hold. 247 * 248 * If the fed devfreq_simple_ondemand_data pointer is NULL to the governor, 249 * the governor uses the default values. 250 */ 251 struct devfreq_simple_ondemand_data { 252 unsigned int upthreshold; 253 unsigned int downdifferential; 254 }; 255 #endif 256 257 #if IS_ENABLED(CONFIG_DEVFREQ_GOV_PASSIVE) 258 /** 259 * struct devfreq_passive_data - void *data fed to struct devfreq 260 * and devfreq_add_device 261 * @parent: the devfreq instance of parent device. 262 * @get_target_freq: Optional callback, Returns desired operating frequency 263 * for the device using passive governor. That is called 264 * when passive governor should decide the next frequency 265 * by using the new frequency of parent devfreq device 266 * using governors except for passive governor. 267 * If the devfreq device has the specific method to decide 268 * the next frequency, should use this callback. 269 * @this: the devfreq instance of own device. 270 * @nb: the notifier block for DEVFREQ_TRANSITION_NOTIFIER list 271 * 272 * The devfreq_passive_data have to set the devfreq instance of parent 273 * device with governors except for the passive governor. But, don't need to 274 * initialize the 'this' and 'nb' field because the devfreq core will handle 275 * them. 276 */ 277 struct devfreq_passive_data { 278 /* Should set the devfreq instance of parent device */ 279 struct devfreq *parent; 280 281 /* Optional callback to decide the next frequency of passvice device */ 282 int (*get_target_freq)(struct devfreq *this, unsigned long *freq); 283 284 /* For passive governor's internal use. Don't need to set them */ 285 struct devfreq *this; 286 struct notifier_block nb; 287 }; 288 #endif 289 290 #else /* !CONFIG_PM_DEVFREQ */ 291 static inline struct devfreq *devfreq_add_device(struct device *dev, 292 struct devfreq_dev_profile *profile, 293 const char *governor_name, 294 void *data) 295 { 296 return ERR_PTR(-ENOSYS); 297 } 298 299 static inline int devfreq_remove_device(struct devfreq *devfreq) 300 { 301 return 0; 302 } 303 304 static inline struct devfreq *devm_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 void devm_devfreq_remove_device(struct device *dev, 313 struct devfreq *devfreq) 314 { 315 } 316 317 static inline int devfreq_suspend_device(struct devfreq *devfreq) 318 { 319 return 0; 320 } 321 322 static inline int devfreq_resume_device(struct devfreq *devfreq) 323 { 324 return 0; 325 } 326 327 static inline struct dev_pm_opp *devfreq_recommended_opp(struct device *dev, 328 unsigned long *freq, u32 flags) 329 { 330 return ERR_PTR(-EINVAL); 331 } 332 333 static inline int devfreq_register_opp_notifier(struct device *dev, 334 struct devfreq *devfreq) 335 { 336 return -EINVAL; 337 } 338 339 static inline int devfreq_unregister_opp_notifier(struct device *dev, 340 struct devfreq *devfreq) 341 { 342 return -EINVAL; 343 } 344 345 static inline int devm_devfreq_register_opp_notifier(struct device *dev, 346 struct devfreq *devfreq) 347 { 348 return -EINVAL; 349 } 350 351 static inline void devm_devfreq_unregister_opp_notifier(struct device *dev, 352 struct devfreq *devfreq) 353 { 354 } 355 356 static inline int devfreq_register_notifier(struct devfreq *devfreq, 357 struct notifier_block *nb, 358 unsigned int list) 359 { 360 return 0; 361 } 362 363 static inline int devfreq_unregister_notifier(struct devfreq *devfreq, 364 struct notifier_block *nb, 365 unsigned int list) 366 { 367 return 0; 368 } 369 370 static inline int devm_devfreq_register_notifier(struct device *dev, 371 struct devfreq *devfreq, 372 struct notifier_block *nb, 373 unsigned int list) 374 { 375 return 0; 376 } 377 378 static inline void devm_devfreq_unregister_notifier(struct device *dev, 379 struct devfreq *devfreq, 380 struct notifier_block *nb, 381 unsigned int list) 382 { 383 } 384 385 static inline struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev, 386 int index) 387 { 388 return ERR_PTR(-ENODEV); 389 } 390 391 static inline int devfreq_update_stats(struct devfreq *df) 392 { 393 return -EINVAL; 394 } 395 #endif /* CONFIG_PM_DEVFREQ */ 396 397 #endif /* __LINUX_DEVFREQ_H__ */ 398