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 /* Helper functions for devfreq user device driver with OPP. */ 202 extern struct dev_pm_opp *devfreq_recommended_opp(struct device *dev, 203 unsigned long *freq, u32 flags); 204 extern int devfreq_register_opp_notifier(struct device *dev, 205 struct devfreq *devfreq); 206 extern int devfreq_unregister_opp_notifier(struct device *dev, 207 struct devfreq *devfreq); 208 extern int devm_devfreq_register_opp_notifier(struct device *dev, 209 struct devfreq *devfreq); 210 extern void devm_devfreq_unregister_opp_notifier(struct device *dev, 211 struct devfreq *devfreq); 212 extern int devfreq_register_notifier(struct devfreq *devfreq, 213 struct notifier_block *nb, 214 unsigned int list); 215 extern int devfreq_unregister_notifier(struct devfreq *devfreq, 216 struct notifier_block *nb, 217 unsigned int list); 218 extern int devm_devfreq_register_notifier(struct device *dev, 219 struct devfreq *devfreq, 220 struct notifier_block *nb, 221 unsigned int list); 222 extern void devm_devfreq_unregister_notifier(struct device *dev, 223 struct devfreq *devfreq, 224 struct notifier_block *nb, 225 unsigned int list); 226 extern struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev, 227 int index); 228 229 #if IS_ENABLED(CONFIG_DEVFREQ_GOV_SIMPLE_ONDEMAND) 230 /** 231 * struct devfreq_simple_ondemand_data - void *data fed to struct devfreq 232 * and devfreq_add_device 233 * @upthreshold: If the load is over this value, the frequency jumps. 234 * Specify 0 to use the default. Valid value = 0 to 100. 235 * @downdifferential: If the load is under upthreshold - downdifferential, 236 * the governor may consider slowing the frequency down. 237 * Specify 0 to use the default. Valid value = 0 to 100. 238 * downdifferential < upthreshold must hold. 239 * 240 * If the fed devfreq_simple_ondemand_data pointer is NULL to the governor, 241 * the governor uses the default values. 242 */ 243 struct devfreq_simple_ondemand_data { 244 unsigned int upthreshold; 245 unsigned int downdifferential; 246 }; 247 #endif 248 249 #if IS_ENABLED(CONFIG_DEVFREQ_GOV_PASSIVE) 250 /** 251 * struct devfreq_passive_data - void *data fed to struct devfreq 252 * and devfreq_add_device 253 * @parent: the devfreq instance of parent device. 254 * @get_target_freq: Optional callback, Returns desired operating frequency 255 * for the device using passive governor. That is called 256 * when passive governor should decide the next frequency 257 * by using the new frequency of parent devfreq device 258 * using governors except for passive governor. 259 * If the devfreq device has the specific method to decide 260 * the next frequency, should use this callback. 261 * @this: the devfreq instance of own device. 262 * @nb: the notifier block for DEVFREQ_TRANSITION_NOTIFIER list 263 * 264 * The devfreq_passive_data have to set the devfreq instance of parent 265 * device with governors except for the passive governor. But, don't need to 266 * initialize the 'this' and 'nb' field because the devfreq core will handle 267 * them. 268 */ 269 struct devfreq_passive_data { 270 /* Should set the devfreq instance of parent device */ 271 struct devfreq *parent; 272 273 /* Optional callback to decide the next frequency of passvice device */ 274 int (*get_target_freq)(struct devfreq *this, unsigned long *freq); 275 276 /* For passive governor's internal use. Don't need to set them */ 277 struct devfreq *this; 278 struct notifier_block nb; 279 }; 280 #endif 281 282 #else /* !CONFIG_PM_DEVFREQ */ 283 static inline struct devfreq *devfreq_add_device(struct device *dev, 284 struct devfreq_dev_profile *profile, 285 const char *governor_name, 286 void *data) 287 { 288 return ERR_PTR(-ENOSYS); 289 } 290 291 static inline int devfreq_remove_device(struct devfreq *devfreq) 292 { 293 return 0; 294 } 295 296 static inline struct devfreq *devm_devfreq_add_device(struct device *dev, 297 struct devfreq_dev_profile *profile, 298 const char *governor_name, 299 void *data) 300 { 301 return ERR_PTR(-ENOSYS); 302 } 303 304 static inline void devm_devfreq_remove_device(struct device *dev, 305 struct devfreq *devfreq) 306 { 307 } 308 309 static inline int devfreq_suspend_device(struct devfreq *devfreq) 310 { 311 return 0; 312 } 313 314 static inline int devfreq_resume_device(struct devfreq *devfreq) 315 { 316 return 0; 317 } 318 319 static inline struct dev_pm_opp *devfreq_recommended_opp(struct device *dev, 320 unsigned long *freq, u32 flags) 321 { 322 return ERR_PTR(-EINVAL); 323 } 324 325 static inline int devfreq_register_opp_notifier(struct device *dev, 326 struct devfreq *devfreq) 327 { 328 return -EINVAL; 329 } 330 331 static inline int devfreq_unregister_opp_notifier(struct device *dev, 332 struct devfreq *devfreq) 333 { 334 return -EINVAL; 335 } 336 337 static inline int devm_devfreq_register_opp_notifier(struct device *dev, 338 struct devfreq *devfreq) 339 { 340 return -EINVAL; 341 } 342 343 static inline void devm_devfreq_unregister_opp_notifier(struct device *dev, 344 struct devfreq *devfreq) 345 { 346 } 347 348 static inline int devfreq_register_notifier(struct devfreq *devfreq, 349 struct notifier_block *nb, 350 unsigned int list) 351 { 352 return 0; 353 } 354 355 static inline int devfreq_unregister_notifier(struct devfreq *devfreq, 356 struct notifier_block *nb, 357 unsigned int list) 358 { 359 return 0; 360 } 361 362 static inline int devm_devfreq_register_notifier(struct device *dev, 363 struct devfreq *devfreq, 364 struct notifier_block *nb, 365 unsigned int list) 366 { 367 return 0; 368 } 369 370 static inline void devm_devfreq_unregister_notifier(struct device *dev, 371 struct devfreq *devfreq, 372 struct notifier_block *nb, 373 unsigned int list) 374 { 375 } 376 377 static inline struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev, 378 int index) 379 { 380 return ERR_PTR(-ENODEV); 381 } 382 383 static inline int devfreq_update_stats(struct devfreq *df) 384 { 385 return -EINVAL; 386 } 387 #endif /* CONFIG_PM_DEVFREQ */ 388 389 #endif /* __LINUX_DEVFREQ_H__ */ 390