include/linux/devfreq.h

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2 /*
   3  * devfreq: Generic Dynamic Voltage and Frequency Scaling (DVFS) Framework
   4  *          for Non-CPU Devices.
   5  *
   6  * Copyright (C) 2011 Samsung Electronics
   7  *      MyungJoo Ham <myungjoo.ham@samsung.com>
   8  */
   9
  10 #ifndef __LINUX_DEVFREQ_H__
  11 #define __LINUX_DEVFREQ_H__
  12
  13 #include <linux/device.h>
  14 #include <linux/notifier.h>
  15 #include <linux/pm_opp.h>
  16 #include <linux/pm_qos.h>
  17
  18 /* DEVFREQ governor name */
  19 #define DEVFREQ_GOV_SIMPLE_ONDEMAND     "simple_ondemand"
  20 #define DEVFREQ_GOV_PERFORMANCE         "performance"
  21 #define DEVFREQ_GOV_POWERSAVE           "powersave"
  22 #define DEVFREQ_GOV_USERSPACE           "userspace"
  23 #define DEVFREQ_GOV_PASSIVE             "passive"
  24
  25 /* DEVFREQ notifier interface */
  26 #define DEVFREQ_TRANSITION_NOTIFIER     (0)
  27
  28 /* Transition notifiers of DEVFREQ_TRANSITION_NOTIFIER */
  29 #define DEVFREQ_PRECHANGE               (0)
  30 #define DEVFREQ_POSTCHANGE              (1)
  31
  32 /* DEVFREQ work timers */
  33 enum devfreq_timer {
  34         DEVFREQ_TIMER_DEFERRABLE = 0,
  35         DEVFREQ_TIMER_DELAYED,
  36         DEVFREQ_TIMER_NUM,
  37 };
  38
  39 struct devfreq;
  40 struct devfreq_governor;
  41 struct thermal_cooling_device;
  42
  43 /**
  44  * struct devfreq_dev_status - Data given from devfreq user device to
  45  *                           governors. Represents the performance
  46  *                           statistics.
  47  * @total_time:         The total time represented by this instance of
  48  *                      devfreq_dev_status
  49  * @busy_time:          The time that the device was working among the
  50  *                      total_time.
  51  * @current_frequency:  The operating frequency.
  52  * @private_data:       An entry not specified by the devfreq framework.
  53  *                      A device and a specific governor may have their
  54  *                      own protocol with private_data. However, because
  55  *                      this is governor-specific, a governor using this
  56  *                      will be only compatible with devices aware of it.
  57  */
  58 struct devfreq_dev_status {
  59         /* both since the last measure */
  60         unsigned long total_time;
  61         unsigned long busy_time;
  62         unsigned long current_frequency;
  63         void *private_data;
  64 };
  65
  66 /*
  67  * The resulting frequency should be at most this. (this bound is the
  68  * least upper bound; thus, the resulting freq should be lower or same)
  69  * If the flag is not set, the resulting frequency should be at most the
  70  * bound (greatest lower bound)
  71  */
  72 #define DEVFREQ_FLAG_LEAST_UPPER_BOUND          0x1
  73
  74 /**
  75  * struct devfreq_dev_profile - Devfreq's user device profile
  76  * @initial_freq:       The operating frequency when devfreq_add_device() is
  77  *                      called.
  78  * @polling_ms:         The polling interval in ms. 0 disables polling.
  79  * @timer:              Timer type is either deferrable or delayed timer.
  80  * @target:             The device should set its operating frequency at
  81  *                      freq or lowest-upper-than-freq value. If freq is
  82  *                      higher than any operable frequency, set maximum.
  83  *                      Before returning, target function should set
  84  *                      freq at the current frequency.
  85  *                      The "flags" parameter's possible values are
  86  *                      explained above with "DEVFREQ_FLAG_*" macros.
  87  * @get_dev_status:     The device should provide the current performance
  88  *                      status to devfreq. Governors are recommended not to
  89  *                      use this directly. Instead, governors are recommended
  90  *                      to use devfreq_update_stats() along with
  91  *                      devfreq.last_status.
  92  * @get_cur_freq:       The device should provide the current frequency
  93  *                      at which it is operating.
  94  * @exit:               An optional callback that is called when devfreq
  95  *                      is removing the devfreq object due to error or
  96  *                      from devfreq_remove_device() call. If the user
  97  *                      has registered devfreq->nb at a notifier-head,
  98  *                      this is the time to unregister it.
  99  * @freq_table:         Optional list of frequencies to support statistics
 100  *                      and freq_table must be generated in ascending order.
 101  * @max_state:          The size of freq_table.
 102  *
 103  * @is_cooling_device: A self-explanatory boolean giving the device a
 104  *                     cooling effect property.
 105  */
 106 struct devfreq_dev_profile {
 107         unsigned long initial_freq;
 108         unsigned int polling_ms;
 109         enum devfreq_timer timer;
 110         bool is_cooling_device;
 111
 112         int (*target)(struct device *dev, unsigned long *freq, u32 flags);
 113         int (*get_dev_status)(struct device *dev,
 114                               struct devfreq_dev_status *stat);
 115         int (*get_cur_freq)(struct device *dev, unsigned long *freq);
 116         void (*exit)(struct device *dev);
 117
 118         unsigned long *freq_table;
 119         unsigned int max_state;
 120 };
 121
 122 /**
 123  * struct devfreq_stats - Statistics of devfreq device behavior
 124  * @total_trans:        Number of devfreq transitions.
 125  * @trans_table:        Statistics of devfreq transitions.
 126  * @time_in_state:      Statistics of devfreq states.
 127  * @last_update:        The last time stats were updated.
 128  */
 129 struct devfreq_stats {
 130         unsigned int total_trans;
 131         unsigned int *trans_table;
 132         u64 *time_in_state;
 133         u64 last_update;
 134 };
 135
 136 /**
 137  * struct devfreq - Device devfreq structure
 138  * @node:       list node - contains the devices with devfreq that have been
 139  *              registered.
 140  * @lock:       a mutex to protect accessing devfreq.
 141  * @dev:        device registered by devfreq class. dev.parent is the device
 142  *              using devfreq.
 143  * @profile:    device-specific devfreq profile
 144  * @governor:   method how to choose frequency based on the usage.
 145  * @opp_table:  Reference to OPP table of dev.parent, if one exists.
 146  * @nb:         notifier block used to notify devfreq object that it should
 147  *              reevaluate operable frequencies. Devfreq users may use
 148  *              devfreq.nb to the corresponding register notifier call chain.
 149  * @work:       delayed work for load monitoring.
 150  * @previous_freq:      previously configured frequency value.
 151  * @last_status:        devfreq user device info, performance statistics
 152  * @data:       Private data of the governor. The devfreq framework does not
 153  *              touch this.
 154  * @user_min_freq_req:  PM QoS minimum frequency request from user (via sysfs)
 155  * @user_max_freq_req:  PM QoS maximum frequency request from user (via sysfs)
 156  * @scaling_min_freq:   Limit minimum frequency requested by OPP interface
 157  * @scaling_max_freq:   Limit maximum frequency requested by OPP interface
 158  * @stop_polling:        devfreq polling status of a device.
 159  * @suspend_freq:        frequency of a device set during suspend phase.
 160  * @resume_freq:         frequency of a device set in resume phase.
 161  * @suspend_count:       suspend requests counter for a device.
 162  * @stats:      Statistics of devfreq device behavior
 163  * @transition_notifier_list: list head of DEVFREQ_TRANSITION_NOTIFIER notifier
 164  * @cdev:       Cooling device pointer if the devfreq has cooling property
 165  * @nb_min:             Notifier block for DEV_PM_QOS_MIN_FREQUENCY
 166  * @nb_max:             Notifier block for DEV_PM_QOS_MAX_FREQUENCY
 167  *
 168  * This structure stores the devfreq information for a given device.
 169  *
 170  * Note that when a governor accesses entries in struct devfreq in its
 171  * functions except for the context of callbacks defined in struct
 172  * devfreq_governor, the governor should protect its access with the
 173  * struct mutex lock in struct devfreq. A governor may use this mutex
 174  * to protect its own private data in ``void *data`` as well.
 175  */
 176 struct devfreq {
 177         struct list_head node;
 178
 179         struct mutex lock;
 180         struct device dev;
 181         struct devfreq_dev_profile *profile;
 182         const struct devfreq_governor *governor;
 183         struct opp_table *opp_table;
 184         struct notifier_block nb;
 185         struct delayed_work work;
 186
 187         unsigned long previous_freq;
 188         struct devfreq_dev_status last_status;
 189
 190         void *data; /* private data for governors */
 191
 192         struct dev_pm_qos_request user_min_freq_req;
 193         struct dev_pm_qos_request user_max_freq_req;
 194         unsigned long scaling_min_freq;
 195         unsigned long scaling_max_freq;
 196         bool stop_polling;
 197
 198         unsigned long suspend_freq;
 199         unsigned long resume_freq;
 200         atomic_t suspend_count;
 201
 202         /* information for device frequency transitions */
 203         struct devfreq_stats stats;
 204
 205         struct srcu_notifier_head transition_notifier_list;
 206
 207         /* Pointer to the cooling device if used for thermal mitigation */
 208         struct thermal_cooling_device *cdev;
 209
 210         struct notifier_block nb_min;
 211         struct notifier_block nb_max;
 212 };
 213
 214 struct devfreq_freqs {
 215         unsigned long old;
 216         unsigned long new;
 217 };
 218
 219 #if defined(CONFIG_PM_DEVFREQ)
 220 struct devfreq *devfreq_add_device(struct device *dev,
 221                                 struct devfreq_dev_profile *profile,
 222                                 const char *governor_name,
 223                                 void *data);
 224 int devfreq_remove_device(struct devfreq *devfreq);
 225 struct devfreq *devm_devfreq_add_device(struct device *dev,
 226                                 struct devfreq_dev_profile *profile,
 227                                 const char *governor_name,
 228                                 void *data);
 229 void devm_devfreq_remove_device(struct device *dev, struct devfreq *devfreq);
 230
 231 /* Supposed to be called by PM callbacks */
 232 int devfreq_suspend_device(struct devfreq *devfreq);
 233 int devfreq_resume_device(struct devfreq *devfreq);
 234
 235 void devfreq_suspend(void);
 236 void devfreq_resume(void);
 237
 238 /* update_devfreq() - Reevaluate the device and configure frequency */
 239 int update_devfreq(struct devfreq *devfreq);
 240
 241 /* Helper functions for devfreq user device driver with OPP. */
 242 struct dev_pm_opp *devfreq_recommended_opp(struct device *dev,
 243                                 unsigned long *freq, u32 flags);
 244 int devfreq_register_opp_notifier(struct device *dev,
 245                                 struct devfreq *devfreq);
 246 int devfreq_unregister_opp_notifier(struct device *dev,
 247                                 struct devfreq *devfreq);
 248 int devm_devfreq_register_opp_notifier(struct device *dev,
 249                                 struct devfreq *devfreq);
 250 void devm_devfreq_unregister_opp_notifier(struct device *dev,
 251                                 struct devfreq *devfreq);
 252 int devfreq_register_notifier(struct devfreq *devfreq,
 253                                 struct notifier_block *nb,
 254                                 unsigned int list);
 255 int devfreq_unregister_notifier(struct devfreq *devfreq,
 256                                 struct notifier_block *nb,
 257                                 unsigned int list);
 258 int devm_devfreq_register_notifier(struct device *dev,
 259                                 struct devfreq *devfreq,
 260                                 struct notifier_block *nb,
 261                                 unsigned int list);
 262 void devm_devfreq_unregister_notifier(struct device *dev,
 263                                 struct devfreq *devfreq,
 264                                 struct notifier_block *nb,
 265                                 unsigned int list);
 266 struct devfreq *devfreq_get_devfreq_by_node(struct device_node *node);
 267 struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev,
 268                                 const char *phandle_name, int index);
 269
 270 #if IS_ENABLED(CONFIG_DEVFREQ_GOV_SIMPLE_ONDEMAND)
 271 /**
 272  * struct devfreq_simple_ondemand_data - ``void *data`` fed to struct devfreq
 273  *      and devfreq_add_device
 274  * @upthreshold:        If the load is over this value, the frequency jumps.
 275  *                      Specify 0 to use the default. Valid value = 0 to 100.
 276  * @downdifferential:   If the load is under upthreshold - downdifferential,
 277  *                      the governor may consider slowing the frequency down.
 278  *                      Specify 0 to use the default. Valid value = 0 to 100.
 279  *                      downdifferential < upthreshold must hold.
 280  *
 281  * If the fed devfreq_simple_ondemand_data pointer is NULL to the governor,
 282  * the governor uses the default values.
 283  */
 284 struct devfreq_simple_ondemand_data {
 285         unsigned int upthreshold;
 286         unsigned int downdifferential;
 287 };
 288 #endif
 289
 290 #if IS_ENABLED(CONFIG_DEVFREQ_GOV_PASSIVE)
 291 /**
 292  * struct devfreq_passive_data - ``void *data`` fed to struct devfreq
 293  *      and devfreq_add_device
 294  * @parent:     the devfreq instance of parent device.
 295  * @get_target_freq:    Optional callback, Returns desired operating frequency
 296  *                      for the device using passive governor. That is called
 297  *                      when passive governor should decide the next frequency
 298  *                      by using the new frequency of parent devfreq device
 299  *                      using governors except for passive governor.
 300  *                      If the devfreq device has the specific method to decide
 301  *                      the next frequency, should use this callback.
 302  * @this:       the devfreq instance of own device.
 303  * @nb:         the notifier block for DEVFREQ_TRANSITION_NOTIFIER list
 304  *
 305  * The devfreq_passive_data have to set the devfreq instance of parent
 306  * device with governors except for the passive governor. But, don't need to
 307  * initialize the 'this' and 'nb' field because the devfreq core will handle
 308  * them.
 309  */
 310 struct devfreq_passive_data {
 311         /* Should set the devfreq instance of parent device */
 312         struct devfreq *parent;
 313
 314         /* Optional callback to decide the next frequency of passvice device */
 315         int (*get_target_freq)(struct devfreq *this, unsigned long *freq);
 316
 317         /* For passive governor's internal use. Don't need to set them */
 318         struct devfreq *this;
 319         struct notifier_block nb;
 320 };
 321 #endif
 322
 323 #else /* !CONFIG_PM_DEVFREQ */
 324 static inline struct devfreq *devfreq_add_device(struct device *dev,
 325                                         struct devfreq_dev_profile *profile,
 326                                         const char *governor_name,
 327                                         void *data)
 328 {
 329         return ERR_PTR(-ENOSYS);
 330 }
 331
 332 static inline int devfreq_remove_device(struct devfreq *devfreq)
 333 {
 334         return 0;
 335 }
 336
 337 static inline struct devfreq *devm_devfreq_add_device(struct device *dev,
 338                                         struct devfreq_dev_profile *profile,
 339                                         const char *governor_name,
 340                                         void *data)
 341 {
 342         return ERR_PTR(-ENOSYS);
 343 }
 344
 345 static inline void devm_devfreq_remove_device(struct device *dev,
 346                                         struct devfreq *devfreq)
 347 {
 348 }
 349
 350 static inline int devfreq_suspend_device(struct devfreq *devfreq)
 351 {
 352         return 0;
 353 }
 354
 355 static inline int devfreq_resume_device(struct devfreq *devfreq)
 356 {
 357         return 0;
 358 }
 359
 360 static inline void devfreq_suspend(void) {}
 361 static inline void devfreq_resume(void) {}
 362
 363 static inline struct dev_pm_opp *devfreq_recommended_opp(struct device *dev,
 364                                         unsigned long *freq, u32 flags)
 365 {
 366         return ERR_PTR(-EINVAL);
 367 }
 368
 369 static inline int devfreq_register_opp_notifier(struct device *dev,
 370                                         struct devfreq *devfreq)
 371 {
 372         return -EINVAL;
 373 }
 374
 375 static inline int devfreq_unregister_opp_notifier(struct device *dev,
 376                                         struct devfreq *devfreq)
 377 {
 378         return -EINVAL;
 379 }
 380
 381 static inline int devm_devfreq_register_opp_notifier(struct device *dev,
 382                                         struct devfreq *devfreq)
 383 {
 384         return -EINVAL;
 385 }
 386
 387 static inline void devm_devfreq_unregister_opp_notifier(struct device *dev,
 388                                         struct devfreq *devfreq)
 389 {
 390 }
 391
 392 static inline int devfreq_register_notifier(struct devfreq *devfreq,
 393                                         struct notifier_block *nb,
 394                                         unsigned int list)
 395 {
 396         return 0;
 397 }
 398
 399 static inline int devfreq_unregister_notifier(struct devfreq *devfreq,
 400                                         struct notifier_block *nb,
 401                                         unsigned int list)
 402 {
 403         return 0;
 404 }
 405
 406 static inline int devm_devfreq_register_notifier(struct device *dev,
 407                                         struct devfreq *devfreq,
 408                                         struct notifier_block *nb,
 409                                         unsigned int list)
 410 {
 411         return 0;
 412 }
 413
 414 static inline void devm_devfreq_unregister_notifier(struct device *dev,
 415                                         struct devfreq *devfreq,
 416                                         struct notifier_block *nb,
 417                                         unsigned int list)
 418 {
 419 }
 420
 421 static inline struct devfreq *devfreq_get_devfreq_by_node(struct device_node *node)
 422 {
 423         return ERR_PTR(-ENODEV);
 424 }
 425
 426 static inline struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev,
 427                                         const char *phandle_name, int index)
 428 {
 429         return ERR_PTR(-ENODEV);
 430 }
 431
 432 static inline int devfreq_update_stats(struct devfreq *df)
 433 {
 434         return -EINVAL;
 435 }
 436 #endif /* CONFIG_PM_DEVFREQ */
 437
 438 #endif /* __LINUX_DEVFREQ_H__ */