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 #if IS_ENABLED(CONFIG_DEVFREQ_GOV_SIMPLE_ONDEMAND) 218 /** 219 * struct devfreq_simple_ondemand_data - void *data fed to struct devfreq 220 * and devfreq_add_device 221 * @upthreshold: If the load is over this value, the frequency jumps. 222 * Specify 0 to use the default. Valid value = 0 to 100. 223 * @downdifferential: If the load is under upthreshold - downdifferential, 224 * the governor may consider slowing the frequency down. 225 * Specify 0 to use the default. Valid value = 0 to 100. 226 * downdifferential < upthreshold must hold. 227 * 228 * If the fed devfreq_simple_ondemand_data pointer is NULL to the governor, 229 * the governor uses the default values. 230 */ 231 struct devfreq_simple_ondemand_data { 232 unsigned int upthreshold; 233 unsigned int downdifferential; 234 }; 235 #endif 236 237 #if IS_ENABLED(CONFIG_DEVFREQ_GOV_PASSIVE) 238 /** 239 * struct devfreq_passive_data - void *data fed to struct devfreq 240 * and devfreq_add_device 241 * @parent: the devfreq instance of parent device. 242 * @get_target_freq: Optional callback, Returns desired operating frequency 243 * for the device using passive governor. That is called 244 * when passive governor should decide the next frequency 245 * by using the new frequency of parent devfreq device 246 * using governors except for passive governor. 247 * If the devfreq device has the specific method to decide 248 * the next frequency, should use this callback. 249 * @this: the devfreq instance of own device. 250 * @nb: the notifier block for DEVFREQ_TRANSITION_NOTIFIER list 251 * 252 * The devfreq_passive_data have to set the devfreq instance of parent 253 * device with governors except for the passive governor. But, don't need to 254 * initialize the 'this' and 'nb' field because the devfreq core will handle 255 * them. 256 */ 257 struct devfreq_passive_data { 258 /* Should set the devfreq instance of parent device */ 259 struct devfreq *parent; 260 261 /* Optional callback to decide the next frequency of passvice device */ 262 int (*get_target_freq)(struct devfreq *this, unsigned long *freq); 263 264 /* For passive governor's internal use. Don't need to set them */ 265 struct devfreq *this; 266 struct notifier_block nb; 267 }; 268 #endif 269 270 #else /* !CONFIG_PM_DEVFREQ */ 271 static inline struct devfreq *devfreq_add_device(struct device *dev, 272 struct devfreq_dev_profile *profile, 273 const char *governor_name, 274 void *data) 275 { 276 return ERR_PTR(-ENOSYS); 277 } 278 279 static inline int devfreq_remove_device(struct devfreq *devfreq) 280 { 281 return 0; 282 } 283 284 static inline struct devfreq *devm_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 void devm_devfreq_remove_device(struct device *dev, 293 struct devfreq *devfreq) 294 { 295 } 296 297 static inline int devfreq_suspend_device(struct devfreq *devfreq) 298 { 299 return 0; 300 } 301 302 static inline int devfreq_resume_device(struct devfreq *devfreq) 303 { 304 return 0; 305 } 306 307 static inline struct dev_pm_opp *devfreq_recommended_opp(struct device *dev, 308 unsigned long *freq, u32 flags) 309 { 310 return ERR_PTR(-EINVAL); 311 } 312 313 static inline int devfreq_register_opp_notifier(struct device *dev, 314 struct devfreq *devfreq) 315 { 316 return -EINVAL; 317 } 318 319 static inline int devfreq_unregister_opp_notifier(struct device *dev, 320 struct devfreq *devfreq) 321 { 322 return -EINVAL; 323 } 324 325 static inline int devm_devfreq_register_opp_notifier(struct device *dev, 326 struct devfreq *devfreq) 327 { 328 return -EINVAL; 329 } 330 331 static inline void devm_devfreq_unregister_opp_notifier(struct device *dev, 332 struct devfreq *devfreq) 333 { 334 } 335 336 static inline int devfreq_register_notifier(struct devfreq *devfreq, 337 struct notifier_block *nb, 338 unsigned int list) 339 { 340 return 0; 341 } 342 343 static inline int devfreq_unregister_notifier(struct devfreq *devfreq, 344 struct notifier_block *nb, 345 unsigned int list) 346 { 347 return 0; 348 } 349 350 static inline int devm_devfreq_register_notifier(struct device *dev, 351 struct devfreq *devfreq, 352 struct notifier_block *nb, 353 unsigned int list) 354 { 355 return 0; 356 } 357 358 static inline void devm_devfreq_unregister_notifier(struct device *dev, 359 struct devfreq *devfreq, 360 struct notifier_block *nb, 361 unsigned int list) 362 { 363 } 364 365 static inline struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev, 366 int index) 367 { 368 return ERR_PTR(-ENODEV); 369 } 370 371 static inline int devfreq_update_stats(struct devfreq *df) 372 { 373 return -EINVAL; 374 } 375 #endif /* CONFIG_PM_DEVFREQ */ 376 377 #endif /* __LINUX_DEVFREQ_H__ */ 378