drivers/devfreq/devfreq.c

   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 #include <linux/kernel.h>
  11 #include <linux/kmod.h>
  12 #include <linux/sched.h>
  13 #include <linux/debugfs.h>
  14 #include <linux/errno.h>
  15 #include <linux/err.h>
  16 #include <linux/init.h>
  17 #include <linux/export.h>
  18 #include <linux/slab.h>
  19 #include <linux/stat.h>
  20 #include <linux/pm_opp.h>
  21 #include <linux/devfreq.h>
  22 #include <linux/workqueue.h>
  23 #include <linux/platform_device.h>
  24 #include <linux/list.h>
  25 #include <linux/printk.h>
  26 #include <linux/hrtimer.h>
  27 #include <linux/of.h>
  28 #include <linux/pm_qos.h>
  29 #include "governor.h"
  30
  31 #define CREATE_TRACE_POINTS
  32 #include <trace/events/devfreq.h>
  33
  34 #define HZ_PER_KHZ      1000
  35
  36 static struct class *devfreq_class;
  37 static struct dentry *devfreq_debugfs;
  38
  39 /*
  40  * devfreq core provides delayed work based load monitoring helper
  41  * functions. Governors can use these or can implement their own
  42  * monitoring mechanism.
  43  */
  44 static struct workqueue_struct *devfreq_wq;
  45
  46 /* The list of all device-devfreq governors */
  47 static LIST_HEAD(devfreq_governor_list);
  48 /* The list of all device-devfreq */
  49 static LIST_HEAD(devfreq_list);
  50 static DEFINE_MUTEX(devfreq_list_lock);
  51
  52 static const char timer_name[][DEVFREQ_NAME_LEN] = {
  53         [DEVFREQ_TIMER_DEFERRABLE] = { "deferrable" },
  54         [DEVFREQ_TIMER_DELAYED] = { "delayed" },
  55 };
  56
  57 /**
  58  * find_device_devfreq() - find devfreq struct using device pointer
  59  * @dev:        device pointer used to lookup device devfreq.
  60  *
  61  * Search the list of device devfreqs and return the matched device's
  62  * devfreq info. devfreq_list_lock should be held by the caller.
  63  */
  64 static struct devfreq *find_device_devfreq(struct device *dev)
  65 {
  66         struct devfreq *tmp_devfreq;
  67
  68         lockdep_assert_held(&devfreq_list_lock);
  69
  70         if (IS_ERR_OR_NULL(dev)) {
  71                 pr_err("DEVFREQ: %s: Invalid parameters\n", __func__);
  72                 return ERR_PTR(-EINVAL);
  73         }
  74
  75         list_for_each_entry(tmp_devfreq, &devfreq_list, node) {
  76                 if (tmp_devfreq->dev.parent == dev)
  77                         return tmp_devfreq;
  78         }
  79
  80         return ERR_PTR(-ENODEV);
  81 }
  82
  83 static unsigned long find_available_min_freq(struct devfreq *devfreq)
  84 {
  85         struct dev_pm_opp *opp;
  86         unsigned long min_freq = 0;
  87
  88         opp = dev_pm_opp_find_freq_ceil(devfreq->dev.parent, &min_freq);
  89         if (IS_ERR(opp))
  90                 min_freq = 0;
  91         else
  92                 dev_pm_opp_put(opp);
  93
  94         return min_freq;
  95 }
  96
  97 static unsigned long find_available_max_freq(struct devfreq *devfreq)
  98 {
  99         struct dev_pm_opp *opp;
 100         unsigned long max_freq = ULONG_MAX;
 101
 102         opp = dev_pm_opp_find_freq_floor(devfreq->dev.parent, &max_freq);
 103         if (IS_ERR(opp))
 104                 max_freq = 0;
 105         else
 106                 dev_pm_opp_put(opp);
 107
 108         return max_freq;
 109 }
 110
 111 /**
 112  * get_freq_range() - Get the current freq range
 113  * @devfreq:    the devfreq instance
 114  * @min_freq:   the min frequency
 115  * @max_freq:   the max frequency
 116  *
 117  * This takes into consideration all constraints.
 118  */
 119 static void get_freq_range(struct devfreq *devfreq,
 120                            unsigned long *min_freq,
 121                            unsigned long *max_freq)
 122 {
 123         unsigned long *freq_table = devfreq->profile->freq_table;
 124         s32 qos_min_freq, qos_max_freq;
 125
 126         lockdep_assert_held(&devfreq->lock);
 127
 128         /*
 129          * Initialize minimum/maximum frequency from freq table.
 130          * The devfreq drivers can initialize this in either ascending or
 131          * descending order and devfreq core supports both.
 132          */
 133         if (freq_table[0] < freq_table[devfreq->profile->max_state - 1]) {
 134                 *min_freq = freq_table[0];
 135                 *max_freq = freq_table[devfreq->profile->max_state - 1];
 136         } else {
 137                 *min_freq = freq_table[devfreq->profile->max_state - 1];
 138                 *max_freq = freq_table[0];
 139         }
 140
 141         /* Apply constraints from PM QoS */
 142         qos_min_freq = dev_pm_qos_read_value(devfreq->dev.parent,
 143                                              DEV_PM_QOS_MIN_FREQUENCY);
 144         qos_max_freq = dev_pm_qos_read_value(devfreq->dev.parent,
 145                                              DEV_PM_QOS_MAX_FREQUENCY);
 146         *min_freq = max(*min_freq, (unsigned long)HZ_PER_KHZ * qos_min_freq);
 147         if (qos_max_freq != PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE)
 148                 *max_freq = min(*max_freq,
 149                                 (unsigned long)HZ_PER_KHZ * qos_max_freq);
 150
 151         /* Apply constraints from OPP interface */
 152         *min_freq = max(*min_freq, devfreq->scaling_min_freq);
 153         *max_freq = min(*max_freq, devfreq->scaling_max_freq);
 154
 155         if (*min_freq > *max_freq)
 156                 *min_freq = *max_freq;
 157 }
 158
 159 /**
 160  * devfreq_get_freq_level() - Lookup freq_table for the frequency
 161  * @devfreq:    the devfreq instance
 162  * @freq:       the target frequency
 163  */
 164 static int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq)
 165 {
 166         int lev;
 167
 168         for (lev = 0; lev < devfreq->profile->max_state; lev++)
 169                 if (freq == devfreq->profile->freq_table[lev])
 170                         return lev;
 171
 172         return -EINVAL;
 173 }
 174
 175 static int set_freq_table(struct devfreq *devfreq)
 176 {
 177         struct devfreq_dev_profile *profile = devfreq->profile;
 178         struct dev_pm_opp *opp;
 179         unsigned long freq;
 180         int i, count;
 181
 182         /* Initialize the freq_table from OPP table */
 183         count = dev_pm_opp_get_opp_count(devfreq->dev.parent);
 184         if (count <= 0)
 185                 return -EINVAL;
 186
 187         profile->max_state = count;
 188         profile->freq_table = devm_kcalloc(devfreq->dev.parent,
 189                                         profile->max_state,
 190                                         sizeof(*profile->freq_table),
 191                                         GFP_KERNEL);
 192         if (!profile->freq_table) {
 193                 profile->max_state = 0;
 194                 return -ENOMEM;
 195         }
 196
 197         for (i = 0, freq = 0; i < profile->max_state; i++, freq++) {
 198                 opp = dev_pm_opp_find_freq_ceil(devfreq->dev.parent, &freq);
 199                 if (IS_ERR(opp)) {
 200                         devm_kfree(devfreq->dev.parent, profile->freq_table);
 201                         profile->max_state = 0;
 202                         return PTR_ERR(opp);
 203                 }
 204                 dev_pm_opp_put(opp);
 205                 profile->freq_table[i] = freq;
 206         }
 207
 208         return 0;
 209 }
 210
 211 /**
 212  * devfreq_update_status() - Update statistics of devfreq behavior
 213  * @devfreq:    the devfreq instance
 214  * @freq:       the update target frequency
 215  */
 216 int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
 217 {
 218         int lev, prev_lev, ret = 0;
 219         u64 cur_time;
 220
 221         lockdep_assert_held(&devfreq->lock);
 222         cur_time = get_jiffies_64();
 223
 224         /* Immediately exit if previous_freq is not initialized yet. */
 225         if (!devfreq->previous_freq)
 226                 goto out;
 227
 228         prev_lev = devfreq_get_freq_level(devfreq, devfreq->previous_freq);
 229         if (prev_lev < 0) {
 230                 ret = prev_lev;
 231                 goto out;
 232         }
 233
 234         devfreq->stats.time_in_state[prev_lev] +=
 235                         cur_time - devfreq->stats.last_update;
 236
 237         lev = devfreq_get_freq_level(devfreq, freq);
 238         if (lev < 0) {
 239                 ret = lev;
 240                 goto out;
 241         }
 242
 243         if (lev != prev_lev) {
 244                 devfreq->stats.trans_table[
 245                         (prev_lev * devfreq->profile->max_state) + lev]++;
 246                 devfreq->stats.total_trans++;
 247         }
 248
 249 out:
 250         devfreq->stats.last_update = cur_time;
 251         return ret;
 252 }
 253 EXPORT_SYMBOL(devfreq_update_status);
 254
 255 /**
 256  * find_devfreq_governor() - find devfreq governor from name
 257  * @name:       name of the governor
 258  *
 259  * Search the list of devfreq governors and return the matched
 260  * governor's pointer. devfreq_list_lock should be held by the caller.
 261  */
 262 static struct devfreq_governor *find_devfreq_governor(const char *name)
 263 {
 264         struct devfreq_governor *tmp_governor;
 265
 266         lockdep_assert_held(&devfreq_list_lock);
 267
 268         if (IS_ERR_OR_NULL(name)) {
 269                 pr_err("DEVFREQ: %s: Invalid parameters\n", __func__);
 270                 return ERR_PTR(-EINVAL);
 271         }
 272
 273         list_for_each_entry(tmp_governor, &devfreq_governor_list, node) {
 274                 if (!strncmp(tmp_governor->name, name, DEVFREQ_NAME_LEN))
 275                         return tmp_governor;
 276         }
 277
 278         return ERR_PTR(-ENODEV);
 279 }
 280
 281 /**
 282  * try_then_request_governor() - Try to find the governor and request the
 283  *                               module if is not found.
 284  * @name:       name of the governor
 285  *
 286  * Search the list of devfreq governors and request the module and try again
 287  * if is not found. This can happen when both drivers (the governor driver
 288  * and the driver that call devfreq_add_device) are built as modules.
 289  * devfreq_list_lock should be held by the caller. Returns the matched
 290  * governor's pointer or an error pointer.
 291  */
 292 static struct devfreq_governor *try_then_request_governor(const char *name)
 293 {
 294         struct devfreq_governor *governor;
 295         int err = 0;
 296
 297         lockdep_assert_held(&devfreq_list_lock);
 298
 299         if (IS_ERR_OR_NULL(name)) {
 300                 pr_err("DEVFREQ: %s: Invalid parameters\n", __func__);
 301                 return ERR_PTR(-EINVAL);
 302         }
 303
 304         governor = find_devfreq_governor(name);
 305         if (IS_ERR(governor)) {
 306                 mutex_unlock(&devfreq_list_lock);
 307
 308                 if (!strncmp(name, DEVFREQ_GOV_SIMPLE_ONDEMAND,
 309                              DEVFREQ_NAME_LEN))
 310                         err = request_module("governor_%s", "simpleondemand");
 311                 else
 312                         err = request_module("governor_%s", name);
 313                 /* Restore previous state before return */
 314                 mutex_lock(&devfreq_list_lock);
 315                 if (err)
 316                         return (err < 0) ? ERR_PTR(err) : ERR_PTR(-EINVAL);
 317
 318                 governor = find_devfreq_governor(name);
 319         }
 320
 321         return governor;
 322 }
 323
 324 static int devfreq_notify_transition(struct devfreq *devfreq,
 325                 struct devfreq_freqs *freqs, unsigned int state)
 326 {
 327         if (!devfreq)
 328                 return -EINVAL;
 329
 330         switch (state) {
 331         case DEVFREQ_PRECHANGE:
 332                 srcu_notifier_call_chain(&devfreq->transition_notifier_list,
 333                                 DEVFREQ_PRECHANGE, freqs);
 334                 break;
 335
 336         case DEVFREQ_POSTCHANGE:
 337                 srcu_notifier_call_chain(&devfreq->transition_notifier_list,
 338                                 DEVFREQ_POSTCHANGE, freqs);
 339                 break;
 340         default:
 341                 return -EINVAL;
 342         }
 343
 344         return 0;
 345 }
 346
 347 static int devfreq_set_target(struct devfreq *devfreq, unsigned long new_freq,
 348                               u32 flags)
 349 {
 350         struct devfreq_freqs freqs;
 351         unsigned long cur_freq;
 352         int err = 0;
 353
 354         if (devfreq->profile->get_cur_freq)
 355                 devfreq->profile->get_cur_freq(devfreq->dev.parent, &cur_freq);
 356         else
 357                 cur_freq = devfreq->previous_freq;
 358
 359         freqs.old = cur_freq;
 360         freqs.new = new_freq;
 361         devfreq_notify_transition(devfreq, &freqs, DEVFREQ_PRECHANGE);
 362
 363         err = devfreq->profile->target(devfreq->dev.parent, &new_freq, flags);
 364         if (err) {
 365                 freqs.new = cur_freq;
 366                 devfreq_notify_transition(devfreq, &freqs, DEVFREQ_POSTCHANGE);
 367                 return err;
 368         }
 369
 370         freqs.new = new_freq;
 371         devfreq_notify_transition(devfreq, &freqs, DEVFREQ_POSTCHANGE);
 372
 373         if (devfreq_update_status(devfreq, new_freq))
 374                 dev_err(&devfreq->dev,
 375                         "Couldn't update frequency transition information.\n");
 376
 377         devfreq->previous_freq = new_freq;
 378
 379         if (devfreq->suspend_freq)
 380                 devfreq->resume_freq = new_freq;
 381
 382         return err;
 383 }
 384
 385 /* Load monitoring helper functions for governors use */
 386
 387 /**
 388  * update_devfreq() - Reevaluate the device and configure frequency.
 389  * @devfreq:    the devfreq instance.
 390  *
 391  * Note: Lock devfreq->lock before calling update_devfreq
 392  *       This function is exported for governors.
 393  */
 394 int update_devfreq(struct devfreq *devfreq)
 395 {
 396         unsigned long freq, min_freq, max_freq;
 397         int err = 0;
 398         u32 flags = 0;
 399
 400         lockdep_assert_held(&devfreq->lock);
 401
 402         if (!devfreq->governor)
 403                 return -EINVAL;
 404
 405         /* Reevaluate the proper frequency */
 406         err = devfreq->governor->get_target_freq(devfreq, &freq);
 407         if (err)
 408                 return err;
 409         get_freq_range(devfreq, &min_freq, &max_freq);
 410
 411         if (freq < min_freq) {
 412                 freq = min_freq;
 413                 flags &= ~DEVFREQ_FLAG_LEAST_UPPER_BOUND; /* Use GLB */
 414         }
 415         if (freq > max_freq) {
 416                 freq = max_freq;
 417                 flags |= DEVFREQ_FLAG_LEAST_UPPER_BOUND; /* Use LUB */
 418         }
 419
 420         return devfreq_set_target(devfreq, freq, flags);
 421
 422 }
 423 EXPORT_SYMBOL(update_devfreq);
 424
 425 /**
 426  * devfreq_monitor() - Periodically poll devfreq objects.
 427  * @work:       the work struct used to run devfreq_monitor periodically.
 428  *
 429  */
 430 static void devfreq_monitor(struct work_struct *work)
 431 {
 432         int err;
 433         struct devfreq *devfreq = container_of(work,
 434                                         struct devfreq, work.work);
 435
 436         mutex_lock(&devfreq->lock);
 437         err = update_devfreq(devfreq);
 438         if (err)
 439                 dev_err(&devfreq->dev, "dvfs failed with (%d) error\n", err);
 440
 441         if (devfreq->stop_polling)
 442                 goto out;
 443
 444         queue_delayed_work(devfreq_wq, &devfreq->work,
 445                                 msecs_to_jiffies(devfreq->profile->polling_ms));
 446
 447 out:
 448         mutex_unlock(&devfreq->lock);
 449         trace_devfreq_monitor(devfreq);
 450 }
 451
 452 /**
 453  * devfreq_monitor_start() - Start load monitoring of devfreq instance
 454  * @devfreq:    the devfreq instance.
 455  *
 456  * Helper function for starting devfreq device load monitoring. By
 457  * default delayed work based monitoring is supported. Function
 458  * to be called from governor in response to DEVFREQ_GOV_START
 459  * event when device is added to devfreq framework.
 460  */
 461 void devfreq_monitor_start(struct devfreq *devfreq)
 462 {
 463         if (devfreq->governor->interrupt_driven)
 464                 return;
 465
 466         mutex_lock(&devfreq->lock);
 467         if (delayed_work_pending(&devfreq->work))
 468                 goto out;
 469
 470         switch (devfreq->profile->timer) {
 471         case DEVFREQ_TIMER_DEFERRABLE:
 472                 INIT_DEFERRABLE_WORK(&devfreq->work, devfreq_monitor);
 473                 break;
 474         case DEVFREQ_TIMER_DELAYED:
 475                 INIT_DELAYED_WORK(&devfreq->work, devfreq_monitor);
 476                 break;
 477         default:
 478                 goto out;
 479         }
 480
 481         if (devfreq->profile->polling_ms)
 482                 queue_delayed_work(devfreq_wq, &devfreq->work,
 483                         msecs_to_jiffies(devfreq->profile->polling_ms));
 484
 485 out:
 486         devfreq->stop_polling = false;
 487         mutex_unlock(&devfreq->lock);
 488 }
 489 EXPORT_SYMBOL(devfreq_monitor_start);
 490
 491 /**
 492  * devfreq_monitor_stop() - Stop load monitoring of a devfreq instance
 493  * @devfreq:    the devfreq instance.
 494  *
 495  * Helper function to stop devfreq device load monitoring. Function
 496  * to be called from governor in response to DEVFREQ_GOV_STOP
 497  * event when device is removed from devfreq framework.
 498  */
 499 void devfreq_monitor_stop(struct devfreq *devfreq)
 500 {
 501         if (devfreq->governor->interrupt_driven)
 502                 return;
 503
 504         mutex_lock(&devfreq->lock);
 505         if (devfreq->stop_polling) {
 506                 mutex_unlock(&devfreq->lock);
 507                 return;
 508         }
 509
 510         devfreq->stop_polling = true;
 511         mutex_unlock(&devfreq->lock);
 512         cancel_delayed_work_sync(&devfreq->work);
 513 }
 514 EXPORT_SYMBOL(devfreq_monitor_stop);
 515
 516 /**
 517  * devfreq_monitor_suspend() - Suspend load monitoring of a devfreq instance
 518  * @devfreq:    the devfreq instance.
 519  *
 520  * Helper function to suspend devfreq device load monitoring. Function
 521  * to be called from governor in response to DEVFREQ_GOV_SUSPEND
 522  * event or when polling interval is set to zero.
 523  *
 524  * Note: Though this function is same as devfreq_monitor_stop(),
 525  * intentionally kept separate to provide hooks for collecting
 526  * transition statistics.
 527  */
 528 void devfreq_monitor_suspend(struct devfreq *devfreq)
 529 {
 530         mutex_lock(&devfreq->lock);
 531         if (devfreq->stop_polling) {
 532                 mutex_unlock(&devfreq->lock);
 533                 return;
 534         }
 535
 536         devfreq_update_status(devfreq, devfreq->previous_freq);
 537         devfreq->stop_polling = true;
 538         mutex_unlock(&devfreq->lock);
 539
 540         if (devfreq->governor->interrupt_driven)
 541                 return;
 542
 543         cancel_delayed_work_sync(&devfreq->work);
 544 }
 545 EXPORT_SYMBOL(devfreq_monitor_suspend);
 546
 547 /**
 548  * devfreq_monitor_resume() - Resume load monitoring of a devfreq instance
 549  * @devfreq:    the devfreq instance.
 550  *
 551  * Helper function to resume devfreq device load monitoring. Function
 552  * to be called from governor in response to DEVFREQ_GOV_RESUME
 553  * event or when polling interval is set to non-zero.
 554  */
 555 void devfreq_monitor_resume(struct devfreq *devfreq)
 556 {
 557         unsigned long freq;
 558
 559         mutex_lock(&devfreq->lock);
 560         if (!devfreq->stop_polling)
 561                 goto out;
 562
 563         if (devfreq->governor->interrupt_driven)
 564                 goto out_update;
 565
 566         if (!delayed_work_pending(&devfreq->work) &&
 567                         devfreq->profile->polling_ms)
 568                 queue_delayed_work(devfreq_wq, &devfreq->work,
 569                         msecs_to_jiffies(devfreq->profile->polling_ms));
 570
 571 out_update:
 572         devfreq->stats.last_update = get_jiffies_64();
 573         devfreq->stop_polling = false;
 574
 575         if (devfreq->profile->get_cur_freq &&
 576                 !devfreq->profile->get_cur_freq(devfreq->dev.parent, &freq))
 577                 devfreq->previous_freq = freq;
 578
 579 out:
 580         mutex_unlock(&devfreq->lock);
 581 }
 582 EXPORT_SYMBOL(devfreq_monitor_resume);
 583
 584 /**
 585  * devfreq_update_interval() - Update device devfreq monitoring interval
 586  * @devfreq:    the devfreq instance.
 587  * @delay:      new polling interval to be set.
 588  *
 589  * Helper function to set new load monitoring polling interval. Function
 590  * to be called from governor in response to DEVFREQ_GOV_UPDATE_INTERVAL event.
 591  */
 592 void devfreq_update_interval(struct devfreq *devfreq, unsigned int *delay)
 593 {
 594         unsigned int cur_delay = devfreq->profile->polling_ms;
 595         unsigned int new_delay = *delay;
 596
 597         mutex_lock(&devfreq->lock);
 598         devfreq->profile->polling_ms = new_delay;
 599
 600         if (devfreq->stop_polling)
 601                 goto out;
 602
 603         if (devfreq->governor->interrupt_driven)
 604                 goto out;
 605
 606         /* if new delay is zero, stop polling */
 607         if (!new_delay) {
 608                 mutex_unlock(&devfreq->lock);
 609                 cancel_delayed_work_sync(&devfreq->work);
 610                 return;
 611         }
 612
 613         /* if current delay is zero, start polling with new delay */
 614         if (!cur_delay) {
 615                 queue_delayed_work(devfreq_wq, &devfreq->work,
 616                         msecs_to_jiffies(devfreq->profile->polling_ms));
 617                 goto out;
 618         }
 619
 620         /* if current delay is greater than new delay, restart polling */
 621         if (cur_delay > new_delay) {
 622                 mutex_unlock(&devfreq->lock);
 623                 cancel_delayed_work_sync(&devfreq->work);
 624                 mutex_lock(&devfreq->lock);
 625                 if (!devfreq->stop_polling)
 626                         queue_delayed_work(devfreq_wq, &devfreq->work,
 627                                 msecs_to_jiffies(devfreq->profile->polling_ms));
 628         }
 629 out:
 630         mutex_unlock(&devfreq->lock);
 631 }
 632 EXPORT_SYMBOL(devfreq_update_interval);
 633
 634 /**
 635  * devfreq_notifier_call() - Notify that the device frequency requirements
 636  *                           has been changed out of devfreq framework.
 637  * @nb:         the notifier_block (supposed to be devfreq->nb)
 638  * @type:       not used
 639  * @devp:       not used
 640  *
 641  * Called by a notifier that uses devfreq->nb.
 642  */
 643 static int devfreq_notifier_call(struct notifier_block *nb, unsigned long type,
 644                                  void *devp)
 645 {
 646         struct devfreq *devfreq = container_of(nb, struct devfreq, nb);
 647         int err = -EINVAL;
 648
 649         mutex_lock(&devfreq->lock);
 650
 651         devfreq->scaling_min_freq = find_available_min_freq(devfreq);
 652         if (!devfreq->scaling_min_freq)
 653                 goto out;
 654
 655         devfreq->scaling_max_freq = find_available_max_freq(devfreq);
 656         if (!devfreq->scaling_max_freq) {
 657                 devfreq->scaling_max_freq = ULONG_MAX;
 658                 goto out;
 659         }
 660
 661         err = update_devfreq(devfreq);
 662
 663 out:
 664         mutex_unlock(&devfreq->lock);
 665         if (err)
 666                 dev_err(devfreq->dev.parent,
 667                         "failed to update frequency from OPP notifier (%d)\n",
 668                         err);
 669
 670         return NOTIFY_OK;
 671 }
 672
 673 /**
 674  * qos_notifier_call() - Common handler for QoS constraints.
 675  * @devfreq:    the devfreq instance.
 676  */
 677 static int qos_notifier_call(struct devfreq *devfreq)
 678 {
 679         int err;
 680
 681         mutex_lock(&devfreq->lock);
 682         err = update_devfreq(devfreq);
 683         mutex_unlock(&devfreq->lock);
 684         if (err)
 685                 dev_err(devfreq->dev.parent,
 686                         "failed to update frequency from PM QoS (%d)\n",
 687                         err);
 688
 689         return NOTIFY_OK;
 690 }
 691
 692 /**
 693  * qos_min_notifier_call() - Callback for QoS min_freq changes.
 694  * @nb:         Should be devfreq->nb_min
 695  */
 696 static int qos_min_notifier_call(struct notifier_block *nb,
 697                                          unsigned long val, void *ptr)
 698 {
 699         return qos_notifier_call(container_of(nb, struct devfreq, nb_min));
 700 }
 701
 702 /**
 703  * qos_max_notifier_call() - Callback for QoS max_freq changes.
 704  * @nb:         Should be devfreq->nb_max
 705  */
 706 static int qos_max_notifier_call(struct notifier_block *nb,
 707                                          unsigned long val, void *ptr)
 708 {
 709         return qos_notifier_call(container_of(nb, struct devfreq, nb_max));
 710 }
 711
 712 /**
 713  * devfreq_dev_release() - Callback for struct device to release the device.
 714  * @dev:        the devfreq device
 715  *
 716  * Remove devfreq from the list and release its resources.
 717  */
 718 static void devfreq_dev_release(struct device *dev)
 719 {
 720         struct devfreq *devfreq = to_devfreq(dev);
 721         int err;
 722
 723         mutex_lock(&devfreq_list_lock);
 724         list_del(&devfreq->node);
 725         mutex_unlock(&devfreq_list_lock);
 726
 727         err = dev_pm_qos_remove_notifier(devfreq->dev.parent, &devfreq->nb_max,
 728                                          DEV_PM_QOS_MAX_FREQUENCY);
 729         if (err && err != -ENOENT)
 730                 dev_warn(dev->parent,
 731                         "Failed to remove max_freq notifier: %d\n", err);
 732         err = dev_pm_qos_remove_notifier(devfreq->dev.parent, &devfreq->nb_min,
 733                                          DEV_PM_QOS_MIN_FREQUENCY);
 734         if (err && err != -ENOENT)
 735                 dev_warn(dev->parent,
 736                         "Failed to remove min_freq notifier: %d\n", err);
 737
 738         if (dev_pm_qos_request_active(&devfreq->user_max_freq_req)) {
 739                 err = dev_pm_qos_remove_request(&devfreq->user_max_freq_req);
 740                 if (err < 0)
 741                         dev_warn(dev->parent,
 742                                 "Failed to remove max_freq request: %d\n", err);
 743         }
 744         if (dev_pm_qos_request_active(&devfreq->user_min_freq_req)) {
 745                 err = dev_pm_qos_remove_request(&devfreq->user_min_freq_req);
 746                 if (err < 0)
 747                         dev_warn(dev->parent,
 748                                 "Failed to remove min_freq request: %d\n", err);
 749         }
 750
 751         if (devfreq->profile->exit)
 752                 devfreq->profile->exit(devfreq->dev.parent);
 753
 754         mutex_destroy(&devfreq->lock);
 755         srcu_cleanup_notifier_head(&devfreq->transition_notifier_list);
 756         kfree(devfreq);
 757 }
 758
 759 /**
 760  * devfreq_add_device() - Add devfreq feature to the device
 761  * @dev:        the device to add devfreq feature.
 762  * @profile:    device-specific profile to run devfreq.
 763  * @governor_name:      name of the policy to choose frequency.
 764  * @data:       devfreq driver pass to governors, governor should not change it.
 765  */
 766 struct devfreq *devfreq_add_device(struct device *dev,
 767                                    struct devfreq_dev_profile *profile,
 768                                    const char *governor_name,
 769                                    void *data)
 770 {
 771         struct devfreq *devfreq;
 772         struct devfreq_governor *governor;
 773         int err = 0;
 774
 775         if (!dev || !profile || !governor_name) {
 776                 dev_err(dev, "%s: Invalid parameters.\n", __func__);
 777                 return ERR_PTR(-EINVAL);
 778         }
 779
 780         mutex_lock(&devfreq_list_lock);
 781         devfreq = find_device_devfreq(dev);
 782         mutex_unlock(&devfreq_list_lock);
 783         if (!IS_ERR(devfreq)) {
 784                 dev_err(dev, "%s: devfreq device already exists!\n",
 785                         __func__);
 786                 err = -EINVAL;
 787                 goto err_out;
 788         }
 789
 790         devfreq = kzalloc(sizeof(struct devfreq), GFP_KERNEL);
 791         if (!devfreq) {
 792                 err = -ENOMEM;
 793                 goto err_out;
 794         }
 795
 796         mutex_init(&devfreq->lock);
 797         mutex_lock(&devfreq->lock);
 798         devfreq->dev.parent = dev;
 799         devfreq->dev.class = devfreq_class;
 800         devfreq->dev.release = devfreq_dev_release;
 801         INIT_LIST_HEAD(&devfreq->node);
 802         devfreq->profile = profile;
 803         strscpy(devfreq->governor_name, governor_name, DEVFREQ_NAME_LEN);
 804         devfreq->previous_freq = profile->initial_freq;
 805         devfreq->last_status.current_frequency = profile->initial_freq;
 806         devfreq->data = data;
 807         devfreq->nb.notifier_call = devfreq_notifier_call;
 808
 809         if (devfreq->profile->timer < 0
 810                 || devfreq->profile->timer >= DEVFREQ_TIMER_NUM) {
 811                 mutex_unlock(&devfreq->lock);
 812                 err = -EINVAL;
 813                 goto err_dev;
 814         }
 815
 816         if (!devfreq->profile->max_state && !devfreq->profile->freq_table) {
 817                 mutex_unlock(&devfreq->lock);
 818                 err = set_freq_table(devfreq);
 819                 if (err < 0)
 820                         goto err_dev;
 821                 mutex_lock(&devfreq->lock);
 822         }
 823
 824         devfreq->scaling_min_freq = find_available_min_freq(devfreq);
 825         if (!devfreq->scaling_min_freq) {
 826                 mutex_unlock(&devfreq->lock);
 827                 err = -EINVAL;
 828                 goto err_dev;
 829         }
 830
 831         devfreq->scaling_max_freq = find_available_max_freq(devfreq);
 832         if (!devfreq->scaling_max_freq) {
 833                 mutex_unlock(&devfreq->lock);
 834                 err = -EINVAL;
 835                 goto err_dev;
 836         }
 837
 838         devfreq->suspend_freq = dev_pm_opp_get_suspend_opp_freq(dev);
 839         atomic_set(&devfreq->suspend_count, 0);
 840
 841         dev_set_name(&devfreq->dev, "%s", dev_name(dev));
 842         err = device_register(&devfreq->dev);
 843         if (err) {
 844                 mutex_unlock(&devfreq->lock);
 845                 put_device(&devfreq->dev);
 846                 goto err_out;
 847         }
 848
 849         devfreq->stats.trans_table = devm_kzalloc(&devfreq->dev,
 850                         array3_size(sizeof(unsigned int),
 851                                     devfreq->profile->max_state,
 852                                     devfreq->profile->max_state),
 853                         GFP_KERNEL);
 854         if (!devfreq->stats.trans_table) {
 855                 mutex_unlock(&devfreq->lock);
 856                 err = -ENOMEM;
 857                 goto err_devfreq;
 858         }
 859
 860         devfreq->stats.time_in_state = devm_kcalloc(&devfreq->dev,
 861                         devfreq->profile->max_state,
 862                         sizeof(*devfreq->stats.time_in_state),
 863                         GFP_KERNEL);
 864         if (!devfreq->stats.time_in_state) {
 865                 mutex_unlock(&devfreq->lock);
 866                 err = -ENOMEM;
 867                 goto err_devfreq;
 868         }
 869
 870         devfreq->stats.total_trans = 0;
 871         devfreq->stats.last_update = get_jiffies_64();
 872
 873         srcu_init_notifier_head(&devfreq->transition_notifier_list);
 874
 875         mutex_unlock(&devfreq->lock);
 876
 877         err = dev_pm_qos_add_request(dev, &devfreq->user_min_freq_req,
 878                                      DEV_PM_QOS_MIN_FREQUENCY, 0);
 879         if (err < 0)
 880                 goto err_devfreq;
 881         err = dev_pm_qos_add_request(dev, &devfreq->user_max_freq_req,
 882                                      DEV_PM_QOS_MAX_FREQUENCY,
 883                                      PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE);
 884         if (err < 0)
 885                 goto err_devfreq;
 886
 887         devfreq->nb_min.notifier_call = qos_min_notifier_call;
 888         err = dev_pm_qos_add_notifier(devfreq->dev.parent, &devfreq->nb_min,
 889                                       DEV_PM_QOS_MIN_FREQUENCY);
 890         if (err)
 891                 goto err_devfreq;
 892
 893         devfreq->nb_max.notifier_call = qos_max_notifier_call;
 894         err = dev_pm_qos_add_notifier(devfreq->dev.parent, &devfreq->nb_max,
 895                                       DEV_PM_QOS_MAX_FREQUENCY);
 896         if (err)
 897                 goto err_devfreq;
 898
 899         mutex_lock(&devfreq_list_lock);
 900
 901         governor = try_then_request_governor(devfreq->governor_name);
 902         if (IS_ERR(governor)) {
 903                 dev_err(dev, "%s: Unable to find governor for the device\n",
 904                         __func__);
 905                 err = PTR_ERR(governor);
 906                 goto err_init;
 907         }
 908
 909         devfreq->governor = governor;
 910         err = devfreq->governor->event_handler(devfreq, DEVFREQ_GOV_START,
 911                                                 NULL);
 912         if (err) {
 913                 dev_err(dev, "%s: Unable to start governor for the device\n",
 914                         __func__);
 915                 goto err_init;
 916         }
 917
 918         list_add(&devfreq->node, &devfreq_list);
 919
 920         mutex_unlock(&devfreq_list_lock);
 921
 922         return devfreq;
 923
 924 err_init:
 925         mutex_unlock(&devfreq_list_lock);
 926 err_devfreq:
 927         devfreq_remove_device(devfreq);
 928         devfreq = NULL;
 929 err_dev:
 930         kfree(devfreq);
 931 err_out:
 932         return ERR_PTR(err);
 933 }
 934 EXPORT_SYMBOL(devfreq_add_device);
 935
 936 /**
 937  * devfreq_remove_device() - Remove devfreq feature from a device.
 938  * @devfreq:    the devfreq instance to be removed
 939  *
 940  * The opposite of devfreq_add_device().
 941  */
 942 int devfreq_remove_device(struct devfreq *devfreq)
 943 {
 944         if (!devfreq)
 945                 return -EINVAL;
 946
 947         if (devfreq->governor)
 948                 devfreq->governor->event_handler(devfreq,
 949                                                  DEVFREQ_GOV_STOP, NULL);
 950         device_unregister(&devfreq->dev);
 951
 952         return 0;
 953 }
 954 EXPORT_SYMBOL(devfreq_remove_device);
 955
 956 static int devm_devfreq_dev_match(struct device *dev, void *res, void *data)
 957 {
 958         struct devfreq **r = res;
 959
 960         if (WARN_ON(!r || !*r))
 961                 return 0;
 962
 963         return *r == data;
 964 }
 965
 966 static void devm_devfreq_dev_release(struct device *dev, void *res)
 967 {
 968         devfreq_remove_device(*(struct devfreq **)res);
 969 }
 970
 971 /**
 972  * devm_devfreq_add_device() - Resource-managed devfreq_add_device()
 973  * @dev:        the device to add devfreq feature.
 974  * @profile:    device-specific profile to run devfreq.
 975  * @governor_name:      name of the policy to choose frequency.
 976  * @data:        devfreq driver pass to governors, governor should not change it.
 977  *
 978  * This function manages automatically the memory of devfreq device using device
 979  * resource management and simplify the free operation for memory of devfreq
 980  * device.
 981  */
 982 struct devfreq *devm_devfreq_add_device(struct device *dev,
 983                                         struct devfreq_dev_profile *profile,
 984                                         const char *governor_name,
 985                                         void *data)
 986 {
 987         struct devfreq **ptr, *devfreq;
 988
 989         ptr = devres_alloc(devm_devfreq_dev_release, sizeof(*ptr), GFP_KERNEL);
 990         if (!ptr)
 991                 return ERR_PTR(-ENOMEM);
 992
 993         devfreq = devfreq_add_device(dev, profile, governor_name, data);
 994         if (IS_ERR(devfreq)) {
 995                 devres_free(ptr);
 996                 return devfreq;
 997         }
 998
 999         *ptr = devfreq;
1000         devres_add(dev, ptr);
1001
1002         return devfreq;
1003 }
1004 EXPORT_SYMBOL(devm_devfreq_add_device);
1005
1006 #ifdef CONFIG_OF
1007 /*
1008  * devfreq_get_devfreq_by_node - Get the devfreq device from devicetree
1009  * @node - pointer to device_node
1010  *
1011  * return the instance of devfreq device
1012  */
1013 struct devfreq *devfreq_get_devfreq_by_node(struct device_node *node)
1014 {
1015         struct devfreq *devfreq;
1016
1017         if (!node)
1018                 return ERR_PTR(-EINVAL);
1019
1020         mutex_lock(&devfreq_list_lock);
1021         list_for_each_entry(devfreq, &devfreq_list, node) {
1022                 if (devfreq->dev.parent
1023                         && devfreq->dev.parent->of_node == node) {
1024                         mutex_unlock(&devfreq_list_lock);
1025                         return devfreq;
1026                 }
1027         }
1028         mutex_unlock(&devfreq_list_lock);
1029
1030         return ERR_PTR(-ENODEV);
1031 }
1032
1033 /*
1034  * devfreq_get_devfreq_by_phandle - Get the devfreq device from devicetree
1035  * @dev - instance to the given device
1036  * @phandle_name - name of property holding a phandle value
1037  * @index - index into list of devfreq
1038  *
1039  * return the instance of devfreq device
1040  */
1041 struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev,
1042                                         const char *phandle_name, int index)
1043 {
1044         struct device_node *node;
1045         struct devfreq *devfreq;
1046
1047         if (!dev || !phandle_name)
1048                 return ERR_PTR(-EINVAL);
1049
1050         if (!dev->of_node)
1051                 return ERR_PTR(-EINVAL);
1052
1053         node = of_parse_phandle(dev->of_node, phandle_name, index);
1054         if (!node)
1055                 return ERR_PTR(-ENODEV);
1056
1057         devfreq = devfreq_get_devfreq_by_node(node);
1058         of_node_put(node);
1059
1060         return devfreq;
1061 }
1062
1063 #else
1064 struct devfreq *devfreq_get_devfreq_by_node(struct device_node *node)
1065 {
1066         return ERR_PTR(-ENODEV);
1067 }
1068
1069 struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev,
1070                                         const char *phandle_name, int index)
1071 {
1072         return ERR_PTR(-ENODEV);
1073 }
1074 #endif /* CONFIG_OF */
1075 EXPORT_SYMBOL_GPL(devfreq_get_devfreq_by_node);
1076 EXPORT_SYMBOL_GPL(devfreq_get_devfreq_by_phandle);
1077
1078 /**
1079  * devm_devfreq_remove_device() - Resource-managed devfreq_remove_device()
1080  * @dev:        the device from which to remove devfreq feature.
1081  * @devfreq:    the devfreq instance to be removed
1082  */
1083 void devm_devfreq_remove_device(struct device *dev, struct devfreq *devfreq)
1084 {
1085         WARN_ON(devres_release(dev, devm_devfreq_dev_release,
1086                                devm_devfreq_dev_match, devfreq));
1087 }
1088 EXPORT_SYMBOL(devm_devfreq_remove_device);
1089
1090 /**
1091  * devfreq_suspend_device() - Suspend devfreq of a device.
1092  * @devfreq: the devfreq instance to be suspended
1093  *
1094  * This function is intended to be called by the pm callbacks
1095  * (e.g., runtime_suspend, suspend) of the device driver that
1096  * holds the devfreq.
1097  */
1098 int devfreq_suspend_device(struct devfreq *devfreq)
1099 {
1100         int ret;
1101
1102         if (!devfreq)
1103                 return -EINVAL;
1104
1105         if (atomic_inc_return(&devfreq->suspend_count) > 1)
1106                 return 0;
1107
1108         if (devfreq->governor) {
1109                 ret = devfreq->governor->event_handler(devfreq,
1110                                         DEVFREQ_GOV_SUSPEND, NULL);
1111                 if (ret)
1112                         return ret;
1113         }
1114
1115         if (devfreq->suspend_freq) {
1116                 mutex_lock(&devfreq->lock);
1117                 ret = devfreq_set_target(devfreq, devfreq->suspend_freq, 0);
1118                 mutex_unlock(&devfreq->lock);
1119                 if (ret)
1120                         return ret;
1121         }
1122
1123         return 0;
1124 }
1125 EXPORT_SYMBOL(devfreq_suspend_device);
1126
1127 /**
1128  * devfreq_resume_device() - Resume devfreq of a device.
1129  * @devfreq: the devfreq instance to be resumed
1130  *
1131  * This function is intended to be called by the pm callbacks
1132  * (e.g., runtime_resume, resume) of the device driver that
1133  * holds the devfreq.
1134  */
1135 int devfreq_resume_device(struct devfreq *devfreq)
1136 {
1137         int ret;
1138
1139         if (!devfreq)
1140                 return -EINVAL;
1141
1142         if (atomic_dec_return(&devfreq->suspend_count) >= 1)
1143                 return 0;
1144
1145         if (devfreq->resume_freq) {
1146                 mutex_lock(&devfreq->lock);
1147                 ret = devfreq_set_target(devfreq, devfreq->resume_freq, 0);
1148                 mutex_unlock(&devfreq->lock);
1149                 if (ret)
1150                         return ret;
1151         }
1152
1153         if (devfreq->governor) {
1154                 ret = devfreq->governor->event_handler(devfreq,
1155                                         DEVFREQ_GOV_RESUME, NULL);
1156                 if (ret)
1157                         return ret;
1158         }
1159
1160         return 0;
1161 }
1162 EXPORT_SYMBOL(devfreq_resume_device);
1163
1164 /**
1165  * devfreq_suspend() - Suspend devfreq governors and devices
1166  *
1167  * Called during system wide Suspend/Hibernate cycles for suspending governors
1168  * and devices preserving the state for resume. On some platforms the devfreq
1169  * device must have precise state (frequency) after resume in order to provide
1170  * fully operating setup.
1171  */
1172 void devfreq_suspend(void)
1173 {
1174         struct devfreq *devfreq;
1175         int ret;
1176
1177         mutex_lock(&devfreq_list_lock);
1178         list_for_each_entry(devfreq, &devfreq_list, node) {
1179                 ret = devfreq_suspend_device(devfreq);
1180                 if (ret)
1181                         dev_err(&devfreq->dev,
1182                                 "failed to suspend devfreq device\n");
1183         }
1184         mutex_unlock(&devfreq_list_lock);
1185 }
1186
1187 /**
1188  * devfreq_resume() - Resume devfreq governors and devices
1189  *
1190  * Called during system wide Suspend/Hibernate cycle for resuming governors and
1191  * devices that are suspended with devfreq_suspend().
1192  */
1193 void devfreq_resume(void)
1194 {
1195         struct devfreq *devfreq;
1196         int ret;
1197
1198         mutex_lock(&devfreq_list_lock);
1199         list_for_each_entry(devfreq, &devfreq_list, node) {
1200                 ret = devfreq_resume_device(devfreq);
1201                 if (ret)
1202                         dev_warn(&devfreq->dev,
1203                                  "failed to resume devfreq device\n");
1204         }
1205         mutex_unlock(&devfreq_list_lock);
1206 }
1207
1208 /**
1209  * devfreq_add_governor() - Add devfreq governor
1210  * @governor:   the devfreq governor to be added
1211  */
1212 int devfreq_add_governor(struct devfreq_governor *governor)
1213 {
1214         struct devfreq_governor *g;
1215         struct devfreq *devfreq;
1216         int err = 0;
1217
1218         if (!governor) {
1219                 pr_err("%s: Invalid parameters.\n", __func__);
1220                 return -EINVAL;
1221         }
1222
1223         mutex_lock(&devfreq_list_lock);
1224         g = find_devfreq_governor(governor->name);
1225         if (!IS_ERR(g)) {
1226                 pr_err("%s: governor %s already registered\n", __func__,
1227                        g->name);
1228                 err = -EINVAL;
1229                 goto err_out;
1230         }
1231
1232         list_add(&governor->node, &devfreq_governor_list);
1233
1234         list_for_each_entry(devfreq, &devfreq_list, node) {
1235                 int ret = 0;
1236                 struct device *dev = devfreq->dev.parent;
1237
1238                 if (!strncmp(devfreq->governor_name, governor->name,
1239                              DEVFREQ_NAME_LEN)) {
1240                         /* The following should never occur */
1241                         if (devfreq->governor) {
1242                                 dev_warn(dev,
1243                                          "%s: Governor %s already present\n",
1244                                          __func__, devfreq->governor->name);
1245                                 ret = devfreq->governor->event_handler(devfreq,
1246                                                         DEVFREQ_GOV_STOP, NULL);
1247                                 if (ret) {
1248                                         dev_warn(dev,
1249                                                  "%s: Governor %s stop = %d\n",
1250                                                  __func__,
1251                                                  devfreq->governor->name, ret);
1252                                 }
1253                                 /* Fall through */
1254                         }
1255                         devfreq->governor = governor;
1256                         ret = devfreq->governor->event_handler(devfreq,
1257                                                 DEVFREQ_GOV_START, NULL);
1258                         if (ret) {
1259                                 dev_warn(dev, "%s: Governor %s start=%d\n",
1260                                          __func__, devfreq->governor->name,
1261                                          ret);
1262                         }
1263                 }
1264         }
1265
1266 err_out:
1267         mutex_unlock(&devfreq_list_lock);
1268
1269         return err;
1270 }
1271 EXPORT_SYMBOL(devfreq_add_governor);
1272
1273 /**
1274  * devfreq_remove_governor() - Remove devfreq feature from a device.
1275  * @governor:   the devfreq governor to be removed
1276  */
1277 int devfreq_remove_governor(struct devfreq_governor *governor)
1278 {
1279         struct devfreq_governor *g;
1280         struct devfreq *devfreq;
1281         int err = 0;
1282
1283         if (!governor) {
1284                 pr_err("%s: Invalid parameters.\n", __func__);
1285                 return -EINVAL;
1286         }
1287
1288         mutex_lock(&devfreq_list_lock);
1289         g = find_devfreq_governor(governor->name);
1290         if (IS_ERR(g)) {
1291                 pr_err("%s: governor %s not registered\n", __func__,
1292                        governor->name);
1293                 err = PTR_ERR(g);
1294                 goto err_out;
1295         }
1296         list_for_each_entry(devfreq, &devfreq_list, node) {
1297                 int ret;
1298                 struct device *dev = devfreq->dev.parent;
1299
1300                 if (!strncmp(devfreq->governor_name, governor->name,
1301                              DEVFREQ_NAME_LEN)) {
1302                         /* we should have a devfreq governor! */
1303                         if (!devfreq->governor) {
1304                                 dev_warn(dev, "%s: Governor %s NOT present\n",
1305                                          __func__, governor->name);
1306                                 continue;
1307                                 /* Fall through */
1308                         }
1309                         ret = devfreq->governor->event_handler(devfreq,
1310                                                 DEVFREQ_GOV_STOP, NULL);
1311                         if (ret) {
1312                                 dev_warn(dev, "%s: Governor %s stop=%d\n",
1313                                          __func__, devfreq->governor->name,
1314                                          ret);
1315                         }
1316                         devfreq->governor = NULL;
1317                 }
1318         }
1319
1320         list_del(&governor->node);
1321 err_out:
1322         mutex_unlock(&devfreq_list_lock);
1323
1324         return err;
1325 }
1326 EXPORT_SYMBOL(devfreq_remove_governor);
1327
1328 static ssize_t name_show(struct device *dev,
1329                         struct device_attribute *attr, char *buf)
1330 {
1331         struct devfreq *df = to_devfreq(dev);
1332         return sprintf(buf, "%s\n", dev_name(df->dev.parent));
1333 }
1334 static DEVICE_ATTR_RO(name);
1335
1336 static ssize_t governor_show(struct device *dev,
1337                              struct device_attribute *attr, char *buf)
1338 {
1339         struct devfreq *df = to_devfreq(dev);
1340
1341         if (!df->governor)
1342                 return -EINVAL;
1343
1344         return sprintf(buf, "%s\n", df->governor->name);
1345 }
1346
1347 static ssize_t governor_store(struct device *dev, struct device_attribute *attr,
1348                               const char *buf, size_t count)
1349 {
1350         struct devfreq *df = to_devfreq(dev);
1351         int ret;
1352         char str_governor[DEVFREQ_NAME_LEN + 1];
1353         const struct devfreq_governor *governor, *prev_governor;
1354
1355         if (!df->governor)
1356                 return -EINVAL;
1357
1358         ret = sscanf(buf, "%" __stringify(DEVFREQ_NAME_LEN) "s", str_governor);
1359         if (ret != 1)
1360                 return -EINVAL;
1361
1362         mutex_lock(&devfreq_list_lock);
1363         governor = try_then_request_governor(str_governor);
1364         if (IS_ERR(governor)) {
1365                 ret = PTR_ERR(governor);
1366                 goto out;
1367         }
1368         if (df->governor == governor) {
1369                 ret = 0;
1370                 goto out;
1371         } else if (df->governor->immutable || governor->immutable) {
1372                 ret = -EINVAL;
1373                 goto out;
1374         }
1375
1376         ret = df->governor->event_handler(df, DEVFREQ_GOV_STOP, NULL);
1377         if (ret) {
1378                 dev_warn(dev, "%s: Governor %s not stopped(%d)\n",
1379                          __func__, df->governor->name, ret);
1380                 goto out;
1381         }
1382
1383         prev_governor = df->governor;
1384         df->governor = governor;
1385         strncpy(df->governor_name, governor->name, DEVFREQ_NAME_LEN);
1386         ret = df->governor->event_handler(df, DEVFREQ_GOV_START, NULL);
1387         if (ret) {
1388                 dev_warn(dev, "%s: Governor %s not started(%d)\n",
1389                          __func__, df->governor->name, ret);
1390                 df->governor = prev_governor;
1391                 strncpy(df->governor_name, prev_governor->name,
1392                         DEVFREQ_NAME_LEN);
1393                 ret = df->governor->event_handler(df, DEVFREQ_GOV_START, NULL);
1394                 if (ret) {
1395                         dev_err(dev,
1396                                 "%s: reverting to Governor %s failed (%d)\n",
1397                                 __func__, df->governor_name, ret);
1398                         df->governor = NULL;
1399                 }
1400         }
1401 out:
1402         mutex_unlock(&devfreq_list_lock);
1403
1404         if (!ret)
1405                 ret = count;
1406         return ret;
1407 }
1408 static DEVICE_ATTR_RW(governor);
1409
1410 static ssize_t available_governors_show(struct device *d,
1411                                         struct device_attribute *attr,
1412                                         char *buf)
1413 {
1414         struct devfreq *df = to_devfreq(d);
1415         ssize_t count = 0;
1416
1417         if (!df->governor)
1418                 return -EINVAL;
1419
1420         mutex_lock(&devfreq_list_lock);
1421
1422         /*
1423          * The devfreq with immutable governor (e.g., passive) shows
1424          * only own governor.
1425          */
1426         if (df->governor->immutable) {
1427                 count = scnprintf(&buf[count], DEVFREQ_NAME_LEN,
1428                                   "%s ", df->governor_name);
1429         /*
1430          * The devfreq device shows the registered governor except for
1431          * immutable governors such as passive governor .
1432          */
1433         } else {
1434                 struct devfreq_governor *governor;
1435
1436                 list_for_each_entry(governor, &devfreq_governor_list, node) {
1437                         if (governor->immutable)
1438                                 continue;
1439                         count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
1440                                            "%s ", governor->name);
1441                 }
1442         }
1443
1444         mutex_unlock(&devfreq_list_lock);
1445
1446         /* Truncate the trailing space */
1447         if (count)
1448                 count--;
1449
1450         count += sprintf(&buf[count], "\n");
1451
1452         return count;
1453 }
1454 static DEVICE_ATTR_RO(available_governors);
1455
1456 static ssize_t cur_freq_show(struct device *dev, struct device_attribute *attr,
1457                              char *buf)
1458 {
1459         unsigned long freq;
1460         struct devfreq *df = to_devfreq(dev);
1461
1462         if (!df->profile)
1463                 return -EINVAL;
1464
1465         if (df->profile->get_cur_freq &&
1466                 !df->profile->get_cur_freq(df->dev.parent, &freq))
1467                 return sprintf(buf, "%lu\n", freq);
1468
1469         return sprintf(buf, "%lu\n", df->previous_freq);
1470 }
1471 static DEVICE_ATTR_RO(cur_freq);
1472
1473 static ssize_t target_freq_show(struct device *dev,
1474                                 struct device_attribute *attr, char *buf)
1475 {
1476         struct devfreq *df = to_devfreq(dev);
1477
1478         return sprintf(buf, "%lu\n", df->previous_freq);
1479 }
1480 static DEVICE_ATTR_RO(target_freq);
1481
1482 static ssize_t polling_interval_show(struct device *dev,
1483                                      struct device_attribute *attr, char *buf)
1484 {
1485         struct devfreq *df = to_devfreq(dev);
1486
1487         if (!df->profile)
1488                 return -EINVAL;
1489
1490         return sprintf(buf, "%d\n", df->profile->polling_ms);
1491 }
1492
1493 static ssize_t polling_interval_store(struct device *dev,
1494                                       struct device_attribute *attr,
1495                                       const char *buf, size_t count)
1496 {
1497         struct devfreq *df = to_devfreq(dev);
1498         unsigned int value;
1499         int ret;
1500
1501         if (!df->governor)
1502                 return -EINVAL;
1503
1504         ret = sscanf(buf, "%u", &value);
1505         if (ret != 1)
1506                 return -EINVAL;
1507
1508         df->governor->event_handler(df, DEVFREQ_GOV_UPDATE_INTERVAL, &value);
1509         ret = count;
1510
1511         return ret;
1512 }
1513 static DEVICE_ATTR_RW(polling_interval);
1514
1515 static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr,
1516                               const char *buf, size_t count)
1517 {
1518         struct devfreq *df = to_devfreq(dev);
1519         unsigned long value;
1520         int ret;
1521
1522         /*
1523          * Protect against theoretical sysfs writes between
1524          * device_add and dev_pm_qos_add_request
1525          */
1526         if (!dev_pm_qos_request_active(&df->user_min_freq_req))
1527                 return -EAGAIN;
1528
1529         ret = sscanf(buf, "%lu", &value);
1530         if (ret != 1)
1531                 return -EINVAL;
1532
1533         /* Round down to kHz for PM QoS */
1534         ret = dev_pm_qos_update_request(&df->user_min_freq_req,
1535                                         value / HZ_PER_KHZ);
1536         if (ret < 0)
1537                 return ret;
1538
1539         return count;
1540 }
1541
1542 static ssize_t min_freq_show(struct device *dev, struct device_attribute *attr,
1543                              char *buf)
1544 {
1545         struct devfreq *df = to_devfreq(dev);
1546         unsigned long min_freq, max_freq;
1547
1548         mutex_lock(&df->lock);
1549         get_freq_range(df, &min_freq, &max_freq);
1550         mutex_unlock(&df->lock);
1551
1552         return sprintf(buf, "%lu\n", min_freq);
1553 }
1554 static DEVICE_ATTR_RW(min_freq);
1555
1556 static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr,
1557                               const char *buf, size_t count)
1558 {
1559         struct devfreq *df = to_devfreq(dev);
1560         unsigned long value;
1561         int ret;
1562
1563         /*
1564          * Protect against theoretical sysfs writes between
1565          * device_add and dev_pm_qos_add_request
1566          */
1567         if (!dev_pm_qos_request_active(&df->user_max_freq_req))
1568                 return -EINVAL;
1569
1570         ret = sscanf(buf, "%lu", &value);
1571         if (ret != 1)
1572                 return -EINVAL;
1573
1574         /*
1575          * PM QoS frequencies are in kHz so we need to convert. Convert by
1576          * rounding upwards so that the acceptable interval never shrinks.
1577          *
1578          * For example if the user writes "666666666" to sysfs this value will
1579          * be converted to 666667 kHz and back to 666667000 Hz before an OPP
1580          * lookup, this ensures that an OPP of 666666666Hz is still accepted.
1581          *
1582          * A value of zero means "no limit".
1583          */
1584         if (value)
1585                 value = DIV_ROUND_UP(value, HZ_PER_KHZ);
1586         else
1587                 value = PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE;
1588
1589         ret = dev_pm_qos_update_request(&df->user_max_freq_req, value);
1590         if (ret < 0)
1591                 return ret;
1592
1593         return count;
1594 }
1595
1596 static ssize_t max_freq_show(struct device *dev, struct device_attribute *attr,
1597                              char *buf)
1598 {
1599         struct devfreq *df = to_devfreq(dev);
1600         unsigned long min_freq, max_freq;
1601
1602         mutex_lock(&df->lock);
1603         get_freq_range(df, &min_freq, &max_freq);
1604         mutex_unlock(&df->lock);
1605
1606         return sprintf(buf, "%lu\n", max_freq);
1607 }
1608 static DEVICE_ATTR_RW(max_freq);
1609
1610 static ssize_t available_frequencies_show(struct device *d,
1611                                           struct device_attribute *attr,
1612                                           char *buf)
1613 {
1614         struct devfreq *df = to_devfreq(d);
1615         ssize_t count = 0;
1616         int i;
1617
1618         if (!df->profile)
1619                 return -EINVAL;
1620
1621         mutex_lock(&df->lock);
1622
1623         for (i = 0; i < df->profile->max_state; i++)
1624                 count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
1625                                 "%lu ", df->profile->freq_table[i]);
1626
1627         mutex_unlock(&df->lock);
1628         /* Truncate the trailing space */
1629         if (count)
1630                 count--;
1631
1632         count += sprintf(&buf[count], "\n");
1633
1634         return count;
1635 }
1636 static DEVICE_ATTR_RO(available_frequencies);
1637
1638 static ssize_t trans_stat_show(struct device *dev,
1639                                struct device_attribute *attr, char *buf)
1640 {
1641         struct devfreq *df = to_devfreq(dev);
1642         ssize_t len;
1643         int i, j;
1644         unsigned int max_state;
1645
1646         if (!df->profile)
1647                 return -EINVAL;
1648         max_state = df->profile->max_state;
1649
1650         if (max_state == 0)
1651                 return sprintf(buf, "Not Supported.\n");
1652
1653         mutex_lock(&df->lock);
1654         if (!df->stop_polling &&
1655                         devfreq_update_status(df, df->previous_freq)) {
1656                 mutex_unlock(&df->lock);
1657                 return 0;
1658         }
1659         mutex_unlock(&df->lock);
1660
1661         len = sprintf(buf, "     From  :   To\n");
1662         len += sprintf(buf + len, "           :");
1663         for (i = 0; i < max_state; i++)
1664                 len += sprintf(buf + len, "%10lu",
1665                                 df->profile->freq_table[i]);
1666
1667         len += sprintf(buf + len, "   time(ms)\n");
1668
1669         for (i = 0; i < max_state; i++) {
1670                 if (df->profile->freq_table[i]
1671                                         == df->previous_freq) {
1672                         len += sprintf(buf + len, "*");
1673                 } else {
1674                         len += sprintf(buf + len, " ");
1675                 }
1676                 len += sprintf(buf + len, "%10lu:",
1677                                 df->profile->freq_table[i]);
1678                 for (j = 0; j < max_state; j++)
1679                         len += sprintf(buf + len, "%10u",
1680                                 df->stats.trans_table[(i * max_state) + j]);
1681
1682                 len += sprintf(buf + len, "%10llu\n", (u64)
1683                         jiffies64_to_msecs(df->stats.time_in_state[i]));
1684         }
1685
1686         len += sprintf(buf + len, "Total transition : %u\n",
1687                                         df->stats.total_trans);
1688         return len;
1689 }
1690
1691 static ssize_t trans_stat_store(struct device *dev,
1692                                 struct device_attribute *attr,
1693                                 const char *buf, size_t count)
1694 {
1695         struct devfreq *df = to_devfreq(dev);
1696         int err, value;
1697
1698         if (!df->profile)
1699                 return -EINVAL;
1700
1701         if (df->profile->max_state == 0)
1702                 return count;
1703
1704         err = kstrtoint(buf, 10, &value);
1705         if (err || value != 0)
1706                 return -EINVAL;
1707
1708         mutex_lock(&df->lock);
1709         memset(df->stats.time_in_state, 0, (df->profile->max_state *
1710                                         sizeof(*df->stats.time_in_state)));
1711         memset(df->stats.trans_table, 0, array3_size(sizeof(unsigned int),
1712                                         df->profile->max_state,
1713                                         df->profile->max_state));
1714         df->stats.total_trans = 0;
1715         df->stats.last_update = get_jiffies_64();
1716         mutex_unlock(&df->lock);
1717
1718         return count;
1719 }
1720 static DEVICE_ATTR_RW(trans_stat);
1721
1722 static ssize_t timer_show(struct device *dev,
1723                              struct device_attribute *attr, char *buf)
1724 {
1725         struct devfreq *df = to_devfreq(dev);
1726
1727         if (!df->profile)
1728                 return -EINVAL;
1729
1730         return sprintf(buf, "%s\n", timer_name[df->profile->timer]);
1731 }
1732
1733 static ssize_t timer_store(struct device *dev, struct device_attribute *attr,
1734                               const char *buf, size_t count)
1735 {
1736         struct devfreq *df = to_devfreq(dev);
1737         char str_timer[DEVFREQ_NAME_LEN + 1];
1738         int timer = -1;
1739         int ret = 0, i;
1740
1741         if (!df->governor || !df->profile)
1742                 return -EINVAL;
1743
1744         ret = sscanf(buf, "%16s", str_timer);
1745         if (ret != 1)
1746                 return -EINVAL;
1747
1748         for (i = 0; i < DEVFREQ_TIMER_NUM; i++) {
1749                 if (!strncmp(timer_name[i], str_timer, DEVFREQ_NAME_LEN)) {
1750                         timer = i;
1751                         break;
1752                 }
1753         }
1754
1755         if (timer < 0) {
1756                 ret = -EINVAL;
1757                 goto out;
1758         }
1759
1760         if (df->profile->timer == timer) {
1761                 ret = 0;
1762                 goto out;
1763         }
1764
1765         mutex_lock(&df->lock);
1766         df->profile->timer = timer;
1767         mutex_unlock(&df->lock);
1768
1769         ret = df->governor->event_handler(df, DEVFREQ_GOV_STOP, NULL);
1770         if (ret) {
1771                 dev_warn(dev, "%s: Governor %s not stopped(%d)\n",
1772                          __func__, df->governor->name, ret);
1773                 goto out;
1774         }
1775
1776         ret = df->governor->event_handler(df, DEVFREQ_GOV_START, NULL);
1777         if (ret)
1778                 dev_warn(dev, "%s: Governor %s not started(%d)\n",
1779                          __func__, df->governor->name, ret);
1780 out:
1781         return ret ? ret : count;
1782 }
1783 static DEVICE_ATTR_RW(timer);
1784
1785 static struct attribute *devfreq_attrs[] = {
1786         &dev_attr_name.attr,
1787         &dev_attr_governor.attr,
1788         &dev_attr_available_governors.attr,
1789         &dev_attr_cur_freq.attr,
1790         &dev_attr_available_frequencies.attr,
1791         &dev_attr_target_freq.attr,
1792         &dev_attr_polling_interval.attr,
1793         &dev_attr_min_freq.attr,
1794         &dev_attr_max_freq.attr,
1795         &dev_attr_trans_stat.attr,
1796         &dev_attr_timer.attr,
1797         NULL,
1798 };
1799 ATTRIBUTE_GROUPS(devfreq);
1800
1801 /**
1802  * devfreq_summary_show() - Show the summary of the devfreq devices
1803  * @s:          seq_file instance to show the summary of devfreq devices
1804  * @data:       not used
1805  *
1806  * Show the summary of the devfreq devices via 'devfreq_summary' debugfs file.
1807  * It helps that user can know the detailed information of the devfreq devices.
1808  *
1809  * Return 0 always because it shows the information without any data change.
1810  */
1811 static int devfreq_summary_show(struct seq_file *s, void *data)
1812 {
1813         struct devfreq *devfreq;
1814         struct devfreq *p_devfreq = NULL;
1815         unsigned long cur_freq, min_freq, max_freq;
1816         unsigned int polling_ms;
1817         unsigned int timer;
1818
1819         seq_printf(s, "%-30s %-30s %-15s %-10s %10s %12s %12s %12s\n",
1820                         "dev",
1821                         "parent_dev",
1822                         "governor",
1823                         "timer",
1824                         "polling_ms",
1825                         "cur_freq_Hz",
1826                         "min_freq_Hz",
1827                         "max_freq_Hz");
1828         seq_printf(s, "%30s %30s %15s %10s %10s %12s %12s %12s\n",
1829                         "------------------------------",
1830                         "------------------------------",
1831                         "---------------",
1832                         "----------",
1833                         "----------",
1834                         "------------",
1835                         "------------",
1836                         "------------");
1837
1838         mutex_lock(&devfreq_list_lock);
1839
1840         list_for_each_entry_reverse(devfreq, &devfreq_list, node) {
1841 #if IS_ENABLED(CONFIG_DEVFREQ_GOV_PASSIVE)
1842                 if (!strncmp(devfreq->governor_name, DEVFREQ_GOV_PASSIVE,
1843                                                         DEVFREQ_NAME_LEN)) {
1844                         struct devfreq_passive_data *data = devfreq->data;
1845
1846                         if (data)
1847                                 p_devfreq = data->parent;
1848                 } else {
1849                         p_devfreq = NULL;
1850                 }
1851 #endif
1852
1853                 mutex_lock(&devfreq->lock);
1854                 cur_freq = devfreq->previous_freq;
1855                 get_freq_range(devfreq, &min_freq, &max_freq);
1856                 polling_ms = devfreq->profile->polling_ms;
1857                 timer = devfreq->profile->timer;
1858                 mutex_unlock(&devfreq->lock);
1859
1860                 seq_printf(s,
1861                         "%-30s %-30s %-15s %-10s %10d %12ld %12ld %12ld\n",
1862                         dev_name(&devfreq->dev),
1863                         p_devfreq ? dev_name(&p_devfreq->dev) : "null",
1864                         devfreq->governor_name,
1865                         polling_ms ? timer_name[timer] : "null",
1866                         polling_ms,
1867                         cur_freq,
1868                         min_freq,
1869                         max_freq);
1870         }
1871
1872         mutex_unlock(&devfreq_list_lock);
1873
1874         return 0;
1875 }
1876 DEFINE_SHOW_ATTRIBUTE(devfreq_summary);
1877
1878 static int __init devfreq_init(void)
1879 {
1880         devfreq_class = class_create(THIS_MODULE, "devfreq");
1881         if (IS_ERR(devfreq_class)) {
1882                 pr_err("%s: couldn't create class\n", __FILE__);
1883                 return PTR_ERR(devfreq_class);
1884         }
1885
1886         devfreq_wq = create_freezable_workqueue("devfreq_wq");
1887         if (!devfreq_wq) {
1888                 class_destroy(devfreq_class);
1889                 pr_err("%s: couldn't create workqueue\n", __FILE__);
1890                 return -ENOMEM;
1891         }
1892         devfreq_class->dev_groups = devfreq_groups;
1893
1894         devfreq_debugfs = debugfs_create_dir("devfreq", NULL);
1895         debugfs_create_file("devfreq_summary", 0444,
1896                                 devfreq_debugfs, NULL,
1897                                 &devfreq_summary_fops);
1898
1899         return 0;
1900 }
1901 subsys_initcall(devfreq_init);
1902
1903 /*
1904  * The following are helper functions for devfreq user device drivers with
1905  * OPP framework.
1906  */
1907
1908 /**
1909  * devfreq_recommended_opp() - Helper function to get proper OPP for the
1910  *                           freq value given to target callback.
1911  * @dev:        The devfreq user device. (parent of devfreq)
1912  * @freq:       The frequency given to target function
1913  * @flags:      Flags handed from devfreq framework.
1914  *
1915  * The callers are required to call dev_pm_opp_put() for the returned OPP after
1916  * use.
1917  */
1918 struct dev_pm_opp *devfreq_recommended_opp(struct device *dev,
1919                                            unsigned long *freq,
1920                                            u32 flags)
1921 {
1922         struct dev_pm_opp *opp;
1923
1924         if (flags & DEVFREQ_FLAG_LEAST_UPPER_BOUND) {
1925                 /* The freq is an upper bound. opp should be lower */
1926                 opp = dev_pm_opp_find_freq_floor(dev, freq);
1927
1928                 /* If not available, use the closest opp */
1929                 if (opp == ERR_PTR(-ERANGE))
1930                         opp = dev_pm_opp_find_freq_ceil(dev, freq);
1931         } else {
1932                 /* The freq is an lower bound. opp should be higher */
1933                 opp = dev_pm_opp_find_freq_ceil(dev, freq);
1934
1935                 /* If not available, use the closest opp */
1936                 if (opp == ERR_PTR(-ERANGE))
1937                         opp = dev_pm_opp_find_freq_floor(dev, freq);
1938         }
1939
1940         return opp;
1941 }
1942 EXPORT_SYMBOL(devfreq_recommended_opp);
1943
1944 /**
1945  * devfreq_register_opp_notifier() - Helper function to get devfreq notified
1946  *                                   for any changes in the OPP availability
1947  *                                   changes
1948  * @dev:        The devfreq user device. (parent of devfreq)
1949  * @devfreq:    The devfreq object.
1950  */
1951 int devfreq_register_opp_notifier(struct device *dev, struct devfreq *devfreq)
1952 {
1953         return dev_pm_opp_register_notifier(dev, &devfreq->nb);
1954 }
1955 EXPORT_SYMBOL(devfreq_register_opp_notifier);
1956
1957 /**
1958  * devfreq_unregister_opp_notifier() - Helper function to stop getting devfreq
1959  *                                     notified for any changes in the OPP
1960  *                                     availability changes anymore.
1961  * @dev:        The devfreq user device. (parent of devfreq)
1962  * @devfreq:    The devfreq object.
1963  *
1964  * At exit() callback of devfreq_dev_profile, this must be included if
1965  * devfreq_recommended_opp is used.
1966  */
1967 int devfreq_unregister_opp_notifier(struct device *dev, struct devfreq *devfreq)
1968 {
1969         return dev_pm_opp_unregister_notifier(dev, &devfreq->nb);
1970 }
1971 EXPORT_SYMBOL(devfreq_unregister_opp_notifier);
1972
1973 static void devm_devfreq_opp_release(struct device *dev, void *res)
1974 {
1975         devfreq_unregister_opp_notifier(dev, *(struct devfreq **)res);
1976 }
1977
1978 /**
1979  * devm_devfreq_register_opp_notifier() - Resource-managed
1980  *                                        devfreq_register_opp_notifier()
1981  * @dev:        The devfreq user device. (parent of devfreq)
1982  * @devfreq:    The devfreq object.
1983  */
1984 int devm_devfreq_register_opp_notifier(struct device *dev,
1985                                        struct devfreq *devfreq)
1986 {
1987         struct devfreq **ptr;
1988         int ret;
1989
1990         ptr = devres_alloc(devm_devfreq_opp_release, sizeof(*ptr), GFP_KERNEL);
1991         if (!ptr)
1992                 return -ENOMEM;
1993
1994         ret = devfreq_register_opp_notifier(dev, devfreq);
1995         if (ret) {
1996                 devres_free(ptr);
1997                 return ret;
1998         }
1999
2000         *ptr = devfreq;
2001         devres_add(dev, ptr);
2002
2003         return 0;
2004 }
2005 EXPORT_SYMBOL(devm_devfreq_register_opp_notifier);
2006
2007 /**
2008  * devm_devfreq_unregister_opp_notifier() - Resource-managed
2009  *                                          devfreq_unregister_opp_notifier()
2010  * @dev:        The devfreq user device. (parent of devfreq)
2011  * @devfreq:    The devfreq object.
2012  */
2013 void devm_devfreq_unregister_opp_notifier(struct device *dev,
2014                                          struct devfreq *devfreq)
2015 {
2016         WARN_ON(devres_release(dev, devm_devfreq_opp_release,
2017                                devm_devfreq_dev_match, devfreq));
2018 }
2019 EXPORT_SYMBOL(devm_devfreq_unregister_opp_notifier);
2020
2021 /**
2022  * devfreq_register_notifier() - Register a driver with devfreq
2023  * @devfreq:    The devfreq object.
2024  * @nb:         The notifier block to register.
2025  * @list:       DEVFREQ_TRANSITION_NOTIFIER.
2026  */
2027 int devfreq_register_notifier(struct devfreq *devfreq,
2028                               struct notifier_block *nb,
2029                               unsigned int list)
2030 {
2031         int ret = 0;
2032
2033         if (!devfreq)
2034                 return -EINVAL;
2035
2036         switch (list) {
2037         case DEVFREQ_TRANSITION_NOTIFIER:
2038                 ret = srcu_notifier_chain_register(
2039                                 &devfreq->transition_notifier_list, nb);
2040                 break;
2041         default:
2042                 ret = -EINVAL;
2043         }
2044
2045         return ret;
2046 }
2047 EXPORT_SYMBOL(devfreq_register_notifier);
2048
2049 /*
2050  * devfreq_unregister_notifier() - Unregister a driver with devfreq
2051  * @devfreq:    The devfreq object.
2052  * @nb:         The notifier block to be unregistered.
2053  * @list:       DEVFREQ_TRANSITION_NOTIFIER.
2054  */
2055 int devfreq_unregister_notifier(struct devfreq *devfreq,
2056                                 struct notifier_block *nb,
2057                                 unsigned int list)
2058 {
2059         int ret = 0;
2060
2061         if (!devfreq)
2062                 return -EINVAL;
2063
2064         switch (list) {
2065         case DEVFREQ_TRANSITION_NOTIFIER:
2066                 ret = srcu_notifier_chain_unregister(
2067                                 &devfreq->transition_notifier_list, nb);
2068                 break;
2069         default:
2070                 ret = -EINVAL;
2071         }
2072
2073         return ret;
2074 }
2075 EXPORT_SYMBOL(devfreq_unregister_notifier);
2076
2077 struct devfreq_notifier_devres {
2078         struct devfreq *devfreq;
2079         struct notifier_block *nb;
2080         unsigned int list;
2081 };
2082
2083 static void devm_devfreq_notifier_release(struct device *dev, void *res)
2084 {
2085         struct devfreq_notifier_devres *this = res;
2086
2087         devfreq_unregister_notifier(this->devfreq, this->nb, this->list);
2088 }
2089
2090 /**
2091  * devm_devfreq_register_notifier()
2092  *      - Resource-managed devfreq_register_notifier()
2093  * @dev:        The devfreq user device. (parent of devfreq)
2094  * @devfreq:    The devfreq object.
2095  * @nb:         The notifier block to be unregistered.
2096  * @list:       DEVFREQ_TRANSITION_NOTIFIER.
2097  */
2098 int devm_devfreq_register_notifier(struct device *dev,
2099                                 struct devfreq *devfreq,
2100                                 struct notifier_block *nb,
2101                                 unsigned int list)
2102 {
2103         struct devfreq_notifier_devres *ptr;
2104         int ret;
2105
2106         ptr = devres_alloc(devm_devfreq_notifier_release, sizeof(*ptr),
2107                                 GFP_KERNEL);
2108         if (!ptr)
2109                 return -ENOMEM;
2110
2111         ret = devfreq_register_notifier(devfreq, nb, list);
2112         if (ret) {
2113                 devres_free(ptr);
2114                 return ret;
2115         }
2116
2117         ptr->devfreq = devfreq;
2118         ptr->nb = nb;
2119         ptr->list = list;
2120         devres_add(dev, ptr);
2121
2122         return 0;
2123 }
2124 EXPORT_SYMBOL(devm_devfreq_register_notifier);
2125
2126 /**
2127  * devm_devfreq_unregister_notifier()
2128  *      - Resource-managed devfreq_unregister_notifier()
2129  * @dev:        The devfreq user device. (parent of devfreq)
2130  * @devfreq:    The devfreq object.
2131  * @nb:         The notifier block to be unregistered.
2132  * @list:       DEVFREQ_TRANSITION_NOTIFIER.
2133  */
2134 void devm_devfreq_unregister_notifier(struct device *dev,
2135                                       struct devfreq *devfreq,
2136                                       struct notifier_block *nb,
2137                                       unsigned int list)
2138 {
2139         WARN_ON(devres_release(dev, devm_devfreq_notifier_release,
2140                                devm_devfreq_dev_match, devfreq));
2141 }
2142 EXPORT_SYMBOL(devm_devfreq_unregister_notifier);