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