include/linux/devfreq.h

   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__ */