drivers/devfreq/devfreq.c

   1 /*
   2  * devfreq: Generic Dynamic Voltage and Frequency Scaling (DVFS) Framework
   3  *          for Non-CPU Devices.
   4  *
   5  * Copyright (C) 2011 Samsung Electronics
   6  *      MyungJoo Ham <[email protected]>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  */
  12
  13 #include <linux/kernel.h>
  14 #include <linux/sched.h>
  15 #include <linux/errno.h>
  16 #include <linux/err.h>
  17 #include <linux/init.h>
  18 #include <linux/export.h>
  19 #include <linux/slab.h>
  20 #include <linux/stat.h>
  21 #include <linux/pm_opp.h>
  22 #include <linux/devfreq.h>
  23 #include <linux/workqueue.h>
  24 #include <linux/platform_device.h>
  25 #include <linux/list.h>
  26 #include <linux/printk.h>
  27 #include <linux/hrtimer.h>
  28 #include <linux/of.h>
  29 #include "governor.h"
  30
  31 static struct class *devfreq_class;
  32
  33 /*
  34  * devfreq core provides delayed work based load monitoring helper
  35  * functions. Governors can use these or can implement their own
  36  * monitoring mechanism.
  37  */
  38 static struct workqueue_struct *devfreq_wq;
  39
  40 /* The list of all device-devfreq governors */
  41 static LIST_HEAD(devfreq_governor_list);
  42 /* The list of all device-devfreq */
  43 static LIST_HEAD(devfreq_list);
  44 static DEFINE_MUTEX(devfreq_list_lock);
  45
  46 /**
  47  * find_device_devfreq() - find devfreq struct using device pointer
  48  * @dev:        device pointer used to lookup device devfreq.
  49  *
  50  * Search the list of device devfreqs and return the matched device's
  51  * devfreq info. devfreq_list_lock should be held by the caller.
  52  */
  53 static struct devfreq *find_device_devfreq(struct device *dev)
  54 {
  55         struct devfreq *tmp_devfreq;
  56
  57         if (IS_ERR_OR_NULL(dev)) {
  58                 pr_err("DEVFREQ: %s: Invalid parameters\n", __func__);
  59                 return ERR_PTR(-EINVAL);
  60         }
  61         WARN(!mutex_is_locked(&devfreq_list_lock),
  62              "devfreq_list_lock must be locked.");
  63
  64         list_for_each_entry(tmp_devfreq, &devfreq_list, node) {
  65                 if (tmp_devfreq->dev.parent == dev)
  66                         return tmp_devfreq;
  67         }
  68
  69         return ERR_PTR(-ENODEV);
  70 }
  71
  72 /**
  73  * devfreq_get_freq_level() - Lookup freq_table for the frequency
  74  * @devfreq:    the devfreq instance
  75  * @freq:       the target frequency
  76  */
  77 static int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq)
  78 {
  79         int lev;
  80
  81         for (lev = 0; lev < devfreq->profile->max_state; lev++)
  82                 if (freq == devfreq->profile->freq_table[lev])
  83                         return lev;
  84
  85         return -EINVAL;
  86 }
  87
  88 /**
  89  * devfreq_set_freq_table() - Initialize freq_table for the frequency
  90  * @devfreq:    the devfreq instance
  91  */
  92 static void devfreq_set_freq_table(struct devfreq *devfreq)
  93 {
  94         struct devfreq_dev_profile *profile = devfreq->profile;
  95         struct dev_pm_opp *opp;
  96         unsigned long freq;
  97         int i, count;
  98
  99         /* Initialize the freq_table from OPP table */
 100         count = dev_pm_opp_get_opp_count(devfreq->dev.parent);
 101         if (count <= 0)
 102                 return;
 103
 104         profile->max_state = count;
 105         profile->freq_table = devm_kcalloc(devfreq->dev.parent,
 106                                         profile->max_state,
 107                                         sizeof(*profile->freq_table),
 108                                         GFP_KERNEL);
 109         if (!profile->freq_table) {
 110                 profile->max_state = 0;
 111                 return;
 112         }
 113
 114         rcu_read_lock();
 115         for (i = 0, freq = 0; i < profile->max_state; i++, freq++) {
 116                 opp = dev_pm_opp_find_freq_ceil(devfreq->dev.parent, &freq);
 117                 if (IS_ERR(opp)) {
 118                         devm_kfree(devfreq->dev.parent, profile->freq_table);
 119                         profile->max_state = 0;
 120                         rcu_read_unlock();
 121                         return;
 122                 }
 123                 profile->freq_table[i] = freq;
 124         }
 125         rcu_read_unlock();
 126 }
 127
 128 /**
 129  * devfreq_update_status() - Update statistics of devfreq behavior
 130  * @devfreq:    the devfreq instance
 131  * @freq:       the update target frequency
 132  */
 133 static int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
 134 {
 135         int lev, prev_lev, ret = 0;
 136         unsigned long cur_time;
 137
 138         cur_time = jiffies;
 139
 140         /* Immediately exit if previous_freq is not initialized yet. */
 141         if (!devfreq->previous_freq)
 142                 goto out;
 143
 144         prev_lev = devfreq_get_freq_level(devfreq, devfreq->previous_freq);
 145         if (prev_lev < 0) {
 146                 ret = prev_lev;
 147                 goto out;
 148         }
 149
 150         devfreq->time_in_state[prev_lev] +=
 151                          cur_time - devfreq->last_stat_updated;
 152
 153         lev = devfreq_get_freq_level(devfreq, freq);
 154         if (lev < 0) {
 155                 ret = lev;
 156                 goto out;
 157         }
 158
 159         if (lev != prev_lev) {
 160                 devfreq->trans_table[(prev_lev *
 161                                 devfreq->profile->max_state) + lev]++;
 162                 devfreq->total_trans++;
 163         }
 164
 165 out:
 166         devfreq->last_stat_updated = cur_time;
 167         return ret;
 168 }
 169
 170 /**
 171  * find_devfreq_governor() - find devfreq governor from name
 172  * @name:       name of the governor
 173  *
 174  * Search the list of devfreq governors and return the matched
 175  * governor's pointer. devfreq_list_lock should be held by the caller.
 176  */
 177 static struct devfreq_governor *find_devfreq_governor(const char *name)
 178 {
 179         struct devfreq_governor *tmp_governor;
 180
 181         if (IS_ERR_OR_NULL(name)) {
 182                 pr_err("DEVFREQ: %s: Invalid parameters\n", __func__);
 183                 return ERR_PTR(-EINVAL);
 184         }
 185         WARN(!mutex_is_locked(&devfreq_list_lock),
 186              "devfreq_list_lock must be locked.");
 187
 188         list_for_each_entry(tmp_governor, &devfreq_governor_list, node) {
 189                 if (!strncmp(tmp_governor->name, name, DEVFREQ_NAME_LEN))
 190                         return tmp_governor;
 191         }
 192
 193         return ERR_PTR(-ENODEV);
 194 }
 195
 196 static int devfreq_notify_transition(struct devfreq *devfreq,
 197                 struct devfreq_freqs *freqs, unsigned int state)
 198 {
 199         if (!devfreq)
 200                 return -EINVAL;
 201
 202         switch (state) {
 203         case DEVFREQ_PRECHANGE:
 204                 srcu_notifier_call_chain(&devfreq->transition_notifier_list,
 205                                 DEVFREQ_PRECHANGE, freqs);
 206                 break;
 207
 208         case DEVFREQ_POSTCHANGE:
 209                 srcu_notifier_call_chain(&devfreq->transition_notifier_list,
 210                                 DEVFREQ_POSTCHANGE, freqs);
 211                 break;
 212         default:
 213                 return -EINVAL;
 214         }
 215
 216         return 0;
 217 }
 218
 219 /* Load monitoring helper functions for governors use */
 220
 221 /**
 222  * update_devfreq() - Reevaluate the device and configure frequency.
 223  * @devfreq:    the devfreq instance.
 224  *
 225  * Note: Lock devfreq->lock before calling update_devfreq
 226  *       This function is exported for governors.
 227  */
 228 int update_devfreq(struct devfreq *devfreq)
 229 {
 230         struct devfreq_freqs freqs;
 231         unsigned long freq, cur_freq;
 232         int err = 0;
 233         u32 flags = 0;
 234
 235         if (!mutex_is_locked(&devfreq->lock)) {
 236                 WARN(true, "devfreq->lock must be locked by the caller.\n");
 237                 return -EINVAL;
 238         }
 239
 240         if (!devfreq->governor)
 241                 return -EINVAL;
 242
 243         /* Reevaluate the proper frequency */
 244         err = devfreq->governor->get_target_freq(devfreq, &freq);
 245         if (err)
 246                 return err;
 247
 248         /*
 249          * Adjust the frequency with user freq and QoS.
 250          *
 251          * List from the highest priority
 252          * max_freq
 253          * min_freq
 254          */
 255
 256         if (devfreq->min_freq && freq < devfreq->min_freq) {
 257                 freq = devfreq->min_freq;
 258                 flags &= ~DEVFREQ_FLAG_LEAST_UPPER_BOUND; /* Use GLB */
 259         }
 260         if (devfreq->max_freq && freq > devfreq->max_freq) {
 261                 freq = devfreq->max_freq;
 262                 flags |= DEVFREQ_FLAG_LEAST_UPPER_BOUND; /* Use LUB */
 263         }
 264
 265         if (devfreq->profile->get_cur_freq)
 266                 devfreq->profile->get_cur_freq(devfreq->dev.parent, &cur_freq);
 267         else
 268                 cur_freq = devfreq->previous_freq;
 269
 270         freqs.old = cur_freq;
 271         freqs.new = freq;
 272         devfreq_notify_transition(devfreq, &freqs, DEVFREQ_PRECHANGE);
 273
 274         err = devfreq->profile->target(devfreq->dev.parent, &freq, flags);
 275         if (err) {
 276                 freqs.new = cur_freq;
 277                 devfreq_notify_transition(devfreq, &freqs, DEVFREQ_POSTCHANGE);
 278                 return err;
 279         }
 280
 281         freqs.new = freq;
 282         devfreq_notify_transition(devfreq, &freqs, DEVFREQ_POSTCHANGE);
 283
 284         if (devfreq->profile->freq_table)
 285                 if (devfreq_update_status(devfreq, freq))
 286                         dev_err(&devfreq->dev,
 287                                 "Couldn't update frequency transition information.\n");
 288
 289         devfreq->previous_freq = freq;
 290         return err;
 291 }
 292 EXPORT_SYMBOL(update_devfreq);
 293
 294 /**
 295  * devfreq_monitor() - Periodically poll devfreq objects.
 296  * @work:       the work struct used to run devfreq_monitor periodically.
 297  *
 298  */
 299 static void devfreq_monitor(struct work_struct *work)
 300 {
 301         int err;
 302         struct devfreq *devfreq = container_of(work,
 303                                         struct devfreq, work.work);
 304
 305         mutex_lock(&devfreq->lock);
 306         err = update_devfreq(devfreq);
 307         if (err)
 308                 dev_err(&devfreq->dev, "dvfs failed with (%d) error\n", err);
 309
 310         queue_delayed_work(devfreq_wq, &devfreq->work,
 311                                 msecs_to_jiffies(devfreq->profile->polling_ms));
 312         mutex_unlock(&devfreq->lock);
 313 }
 314
 315 /**
 316  * devfreq_monitor_start() - Start load monitoring of devfreq instance
 317  * @devfreq:    the devfreq instance.
 318  *
 319  * Helper function for starting devfreq device load monitoing. By
 320  * default delayed work based monitoring is supported. Function
 321  * to be called from governor in response to DEVFREQ_GOV_START
 322  * event when device is added to devfreq framework.
 323  */
 324 void devfreq_monitor_start(struct devfreq *devfreq)
 325 {
 326         INIT_DEFERRABLE_WORK(&devfreq->work, devfreq_monitor);
 327         if (devfreq->profile->polling_ms)
 328                 queue_delayed_work(devfreq_wq, &devfreq->work,
 329                         msecs_to_jiffies(devfreq->profile->polling_ms));
 330 }
 331 EXPORT_SYMBOL(devfreq_monitor_start);
 332
 333 /**
 334  * devfreq_monitor_stop() - Stop load monitoring of a devfreq instance
 335  * @devfreq:    the devfreq instance.
 336  *
 337  * Helper function to stop devfreq device load monitoing. Function
 338  * to be called from governor in response to DEVFREQ_GOV_STOP
 339  * event when device is removed from devfreq framework.
 340  */
 341 void devfreq_monitor_stop(struct devfreq *devfreq)
 342 {
 343         cancel_delayed_work_sync(&devfreq->work);
 344 }
 345 EXPORT_SYMBOL(devfreq_monitor_stop);
 346
 347 /**
 348  * devfreq_monitor_suspend() - Suspend load monitoring of a devfreq instance
 349  * @devfreq:    the devfreq instance.
 350  *
 351  * Helper function to suspend devfreq device load monitoing. Function
 352  * to be called from governor in response to DEVFREQ_GOV_SUSPEND
 353  * event or when polling interval is set to zero.
 354  *
 355  * Note: Though this function is same as devfreq_monitor_stop(),
 356  * intentionally kept separate to provide hooks for collecting
 357  * transition statistics.
 358  */
 359 void devfreq_monitor_suspend(struct devfreq *devfreq)
 360 {
 361         mutex_lock(&devfreq->lock);
 362         if (devfreq->stop_polling) {
 363                 mutex_unlock(&devfreq->lock);
 364                 return;
 365         }
 366
 367         devfreq_update_status(devfreq, devfreq->previous_freq);
 368         devfreq->stop_polling = true;
 369         mutex_unlock(&devfreq->lock);
 370         cancel_delayed_work_sync(&devfreq->work);
 371 }
 372 EXPORT_SYMBOL(devfreq_monitor_suspend);
 373
 374 /**
 375  * devfreq_monitor_resume() - Resume load monitoring of a devfreq instance
 376  * @devfreq:    the devfreq instance.
 377  *
 378  * Helper function to resume devfreq device load monitoing. Function
 379  * to be called from governor in response to DEVFREQ_GOV_RESUME
 380  * event or when polling interval is set to non-zero.
 381  */
 382 void devfreq_monitor_resume(struct devfreq *devfreq)
 383 {
 384         unsigned long freq;
 385
 386         mutex_lock(&devfreq->lock);
 387         if (!devfreq->stop_polling)
 388                 goto out;
 389
 390         if (!delayed_work_pending(&devfreq->work) &&
 391                         devfreq->profile->polling_ms)
 392                 queue_delayed_work(devfreq_wq, &devfreq->work,
 393                         msecs_to_jiffies(devfreq->profile->polling_ms));
 394
 395         devfreq->last_stat_updated = jiffies;
 396         devfreq->stop_polling = false;
 397
 398         if (devfreq->profile->get_cur_freq &&
 399                 !devfreq->profile->get_cur_freq(devfreq->dev.parent, &freq))
 400                 devfreq->previous_freq = freq;
 401
 402 out:
 403         mutex_unlock(&devfreq->lock);
 404 }
 405 EXPORT_SYMBOL(devfreq_monitor_resume);
 406
 407 /**
 408  * devfreq_interval_update() - Update device devfreq monitoring interval
 409  * @devfreq:    the devfreq instance.
 410  * @delay:      new polling interval to be set.
 411  *
 412  * Helper function to set new load monitoring polling interval. Function
 413  * to be called from governor in response to DEVFREQ_GOV_INTERVAL event.
 414  */
 415 void devfreq_interval_update(struct devfreq *devfreq, unsigned int *delay)
 416 {
 417         unsigned int cur_delay = devfreq->profile->polling_ms;
 418         unsigned int new_delay = *delay;
 419
 420         mutex_lock(&devfreq->lock);
 421         devfreq->profile->polling_ms = new_delay;
 422
 423         if (devfreq->stop_polling)
 424                 goto out;
 425
 426         /* if new delay is zero, stop polling */
 427         if (!new_delay) {
 428                 mutex_unlock(&devfreq->lock);
 429                 cancel_delayed_work_sync(&devfreq->work);
 430                 return;
 431         }
 432
 433         /* if current delay is zero, start polling with new delay */
 434         if (!cur_delay) {
 435                 queue_delayed_work(devfreq_wq, &devfreq->work,
 436                         msecs_to_jiffies(devfreq->profile->polling_ms));
 437                 goto out;
 438         }
 439
 440         /* if current delay is greater than new delay, restart polling */
 441         if (cur_delay > new_delay) {
 442                 mutex_unlock(&devfreq->lock);
 443                 cancel_delayed_work_sync(&devfreq->work);
 444                 mutex_lock(&devfreq->lock);
 445                 if (!devfreq->stop_polling)
 446                         queue_delayed_work(devfreq_wq, &devfreq->work,
 447                               msecs_to_jiffies(devfreq->profile->polling_ms));
 448         }
 449 out:
 450         mutex_unlock(&devfreq->lock);
 451 }
 452 EXPORT_SYMBOL(devfreq_interval_update);
 453
 454 /**
 455  * devfreq_notifier_call() - Notify that the device frequency requirements
 456  *                         has been changed out of devfreq framework.
 457  * @nb:         the notifier_block (supposed to be devfreq->nb)
 458  * @type:       not used
 459  * @devp:       not used
 460  *
 461  * Called by a notifier that uses devfreq->nb.
 462  */
 463 static int devfreq_notifier_call(struct notifier_block *nb, unsigned long type,
 464                                  void *devp)
 465 {
 466         struct devfreq *devfreq = container_of(nb, struct devfreq, nb);
 467         int ret;
 468
 469         mutex_lock(&devfreq->lock);
 470         ret = update_devfreq(devfreq);
 471         mutex_unlock(&devfreq->lock);
 472
 473         return ret;
 474 }
 475
 476 /**
 477  * _remove_devfreq() - Remove devfreq from the list and release its resources.
 478  * @devfreq:    the devfreq struct
 479  */
 480 static void _remove_devfreq(struct devfreq *devfreq)
 481 {
 482         mutex_lock(&devfreq_list_lock);
 483         if (IS_ERR(find_device_devfreq(devfreq->dev.parent))) {
 484                 mutex_unlock(&devfreq_list_lock);
 485                 dev_warn(&devfreq->dev, "releasing devfreq which doesn't exist\n");
 486                 return;
 487         }
 488         list_del(&devfreq->node);
 489         mutex_unlock(&devfreq_list_lock);
 490
 491         if (devfreq->governor)
 492                 devfreq->governor->event_handler(devfreq,
 493                                                  DEVFREQ_GOV_STOP, NULL);
 494
 495         if (devfreq->profile->exit)
 496                 devfreq->profile->exit(devfreq->dev.parent);
 497
 498         mutex_destroy(&devfreq->lock);
 499         kfree(devfreq);
 500 }
 501
 502 /**
 503  * devfreq_dev_release() - Callback for struct device to release the device.
 504  * @dev:        the devfreq device
 505  *
 506  * This calls _remove_devfreq() if _remove_devfreq() is not called.
 507  */
 508 static void devfreq_dev_release(struct device *dev)
 509 {
 510         struct devfreq *devfreq = to_devfreq(dev);
 511
 512         _remove_devfreq(devfreq);
 513 }
 514
 515 /**
 516  * devfreq_add_device() - Add devfreq feature to the device
 517  * @dev:        the device to add devfreq feature.
 518  * @profile:    device-specific profile to run devfreq.
 519  * @governor_name:      name of the policy to choose frequency.
 520  * @data:       private data for the governor. The devfreq framework does not
 521  *              touch this value.
 522  */
 523 struct devfreq *devfreq_add_device(struct device *dev,
 524                                    struct devfreq_dev_profile *profile,
 525                                    const char *governor_name,
 526                                    void *data)
 527 {
 528         struct devfreq *devfreq;
 529         struct devfreq_governor *governor;
 530         int err = 0;
 531
 532         if (!dev || !profile || !governor_name) {
 533                 dev_err(dev, "%s: Invalid parameters.\n", __func__);
 534                 return ERR_PTR(-EINVAL);
 535         }
 536
 537         mutex_lock(&devfreq_list_lock);
 538         devfreq = find_device_devfreq(dev);
 539         mutex_unlock(&devfreq_list_lock);
 540         if (!IS_ERR(devfreq)) {
 541                 dev_err(dev, "%s: Unable to create devfreq for the device. It already has one.\n", __func__);
 542                 err = -EINVAL;
 543                 goto err_out;
 544         }
 545
 546         devfreq = kzalloc(sizeof(struct devfreq), GFP_KERNEL);
 547         if (!devfreq) {
 548                 dev_err(dev, "%s: Unable to create devfreq for the device\n",
 549                         __func__);
 550                 err = -ENOMEM;
 551                 goto err_out;
 552         }
 553
 554         mutex_init(&devfreq->lock);
 555         mutex_lock(&devfreq->lock);
 556         devfreq->dev.parent = dev;
 557         devfreq->dev.class = devfreq_class;
 558         devfreq->dev.release = devfreq_dev_release;
 559         devfreq->profile = profile;
 560         strncpy(devfreq->governor_name, governor_name, DEVFREQ_NAME_LEN);
 561         devfreq->previous_freq = profile->initial_freq;
 562         devfreq->last_status.current_frequency = profile->initial_freq;
 563         devfreq->data = data;
 564         devfreq->nb.notifier_call = devfreq_notifier_call;
 565
 566         if (!devfreq->profile->max_state && !devfreq->profile->freq_table) {
 567                 mutex_unlock(&devfreq->lock);
 568                 devfreq_set_freq_table(devfreq);
 569                 mutex_lock(&devfreq->lock);
 570         }
 571
 572         dev_set_name(&devfreq->dev, "%s", dev_name(dev));
 573         err = device_register(&devfreq->dev);
 574         if (err) {
 575                 mutex_unlock(&devfreq->lock);
 576                 goto err_out;
 577         }
 578
 579         devfreq->trans_table =  devm_kzalloc(&devfreq->dev, sizeof(unsigned int) *
 580                                                 devfreq->profile->max_state *
 581                                                 devfreq->profile->max_state,
 582                                                 GFP_KERNEL);
 583         devfreq->time_in_state = devm_kzalloc(&devfreq->dev, sizeof(unsigned long) *
 584                                                 devfreq->profile->max_state,
 585                                                 GFP_KERNEL);
 586         devfreq->last_stat_updated = jiffies;
 587
 588         srcu_init_notifier_head(&devfreq->transition_notifier_list);
 589
 590         mutex_unlock(&devfreq->lock);
 591
 592         mutex_lock(&devfreq_list_lock);
 593         list_add(&devfreq->node, &devfreq_list);
 594
 595         governor = find_devfreq_governor(devfreq->governor_name);
 596         if (!IS_ERR(governor))
 597                 devfreq->governor = governor;
 598         if (devfreq->governor)
 599                 err = devfreq->governor->event_handler(devfreq,
 600                                         DEVFREQ_GOV_START, NULL);
 601         if (err) {
 602                 dev_err(dev, "%s: Unable to start governor for the device\n",
 603                         __func__);
 604                 goto err_init;
 605         }
 606         mutex_unlock(&devfreq_list_lock);
 607
 608         return devfreq;
 609
 610 err_init:
 611         list_del(&devfreq->node);
 612         mutex_unlock(&devfreq_list_lock);
 613
 614         device_unregister(&devfreq->dev);
 615 err_out:
 616         return ERR_PTR(err);
 617 }
 618 EXPORT_SYMBOL(devfreq_add_device);
 619
 620 /**
 621  * devfreq_remove_device() - Remove devfreq feature from a device.
 622  * @devfreq:    the devfreq instance to be removed
 623  *
 624  * The opposite of devfreq_add_device().
 625  */
 626 int devfreq_remove_device(struct devfreq *devfreq)
 627 {
 628         if (!devfreq)
 629                 return -EINVAL;
 630
 631         device_unregister(&devfreq->dev);
 632
 633         return 0;
 634 }
 635 EXPORT_SYMBOL(devfreq_remove_device);
 636
 637 static int devm_devfreq_dev_match(struct device *dev, void *res, void *data)
 638 {
 639         struct devfreq **r = res;
 640
 641         if (WARN_ON(!r || !*r))
 642                 return 0;
 643
 644         return *r == data;
 645 }
 646
 647 static void devm_devfreq_dev_release(struct device *dev, void *res)
 648 {
 649         devfreq_remove_device(*(struct devfreq **)res);
 650 }
 651
 652 /**
 653  * devm_devfreq_add_device() - Resource-managed devfreq_add_device()
 654  * @dev:        the device to add devfreq feature.
 655  * @profile:    device-specific profile to run devfreq.
 656  * @governor_name:      name of the policy to choose frequency.
 657  * @data:       private data for the governor. The devfreq framework does not
 658  *              touch this value.
 659  *
 660  * This function manages automatically the memory of devfreq device using device
 661  * resource management and simplify the free operation for memory of devfreq
 662  * device.
 663  */
 664 struct devfreq *devm_devfreq_add_device(struct device *dev,
 665                                         struct devfreq_dev_profile *profile,
 666                                         const char *governor_name,
 667                                         void *data)
 668 {
 669         struct devfreq **ptr, *devfreq;
 670
 671         ptr = devres_alloc(devm_devfreq_dev_release, sizeof(*ptr), GFP_KERNEL);
 672         if (!ptr)
 673                 return ERR_PTR(-ENOMEM);
 674
 675         devfreq = devfreq_add_device(dev, profile, governor_name, data);
 676         if (IS_ERR(devfreq)) {
 677                 devres_free(ptr);
 678                 return ERR_PTR(-ENOMEM);
 679         }
 680
 681         *ptr = devfreq;
 682         devres_add(dev, ptr);
 683
 684         return devfreq;
 685 }
 686 EXPORT_SYMBOL(devm_devfreq_add_device);
 687
 688 #ifdef CONFIG_OF
 689 /*
 690  * devfreq_get_devfreq_by_phandle - Get the devfreq device from devicetree
 691  * @dev - instance to the given device
 692  * @index - index into list of devfreq
 693  *
 694  * return the instance of devfreq device
 695  */
 696 struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev, int index)
 697 {
 698         struct device_node *node;
 699         struct devfreq *devfreq;
 700
 701         if (!dev)
 702                 return ERR_PTR(-EINVAL);
 703
 704         if (!dev->of_node)
 705                 return ERR_PTR(-EINVAL);
 706
 707         node = of_parse_phandle(dev->of_node, "devfreq", index);
 708         if (!node)
 709                 return ERR_PTR(-ENODEV);
 710
 711         mutex_lock(&devfreq_list_lock);
 712         list_for_each_entry(devfreq, &devfreq_list, node) {
 713                 if (devfreq->dev.parent
 714                         && devfreq->dev.parent->of_node == node) {
 715                         mutex_unlock(&devfreq_list_lock);
 716                         of_node_put(node);
 717                         return devfreq;
 718                 }
 719         }
 720         mutex_unlock(&devfreq_list_lock);
 721         of_node_put(node);
 722
 723         return ERR_PTR(-EPROBE_DEFER);
 724 }
 725 #else
 726 struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev, int index)
 727 {
 728         return ERR_PTR(-ENODEV);
 729 }
 730 #endif /* CONFIG_OF */
 731 EXPORT_SYMBOL_GPL(devfreq_get_devfreq_by_phandle);
 732
 733 /**
 734  * devm_devfreq_remove_device() - Resource-managed devfreq_remove_device()
 735  * @dev:        the device to add devfreq feature.
 736  * @devfreq:    the devfreq instance to be removed
 737  */
 738 void devm_devfreq_remove_device(struct device *dev, struct devfreq *devfreq)
 739 {
 740         WARN_ON(devres_release(dev, devm_devfreq_dev_release,
 741                                devm_devfreq_dev_match, devfreq));
 742 }
 743 EXPORT_SYMBOL(devm_devfreq_remove_device);
 744
 745 /**
 746  * devfreq_suspend_device() - Suspend devfreq of a device.
 747  * @devfreq: the devfreq instance to be suspended
 748  *
 749  * This function is intended to be called by the pm callbacks
 750  * (e.g., runtime_suspend, suspend) of the device driver that
 751  * holds the devfreq.
 752  */
 753 int devfreq_suspend_device(struct devfreq *devfreq)
 754 {
 755         if (!devfreq)
 756                 return -EINVAL;
 757
 758         if (!devfreq->governor)
 759                 return 0;
 760
 761         return devfreq->governor->event_handler(devfreq,
 762                                 DEVFREQ_GOV_SUSPEND, NULL);
 763 }
 764 EXPORT_SYMBOL(devfreq_suspend_device);
 765
 766 /**
 767  * devfreq_resume_device() - Resume devfreq of a device.
 768  * @devfreq: the devfreq instance to be resumed
 769  *
 770  * This function is intended to be called by the pm callbacks
 771  * (e.g., runtime_resume, resume) of the device driver that
 772  * holds the devfreq.
 773  */
 774 int devfreq_resume_device(struct devfreq *devfreq)
 775 {
 776         if (!devfreq)
 777                 return -EINVAL;
 778
 779         if (!devfreq->governor)
 780                 return 0;
 781
 782         return devfreq->governor->event_handler(devfreq,
 783                                 DEVFREQ_GOV_RESUME, NULL);
 784 }
 785 EXPORT_SYMBOL(devfreq_resume_device);
 786
 787 /**
 788  * devfreq_add_governor() - Add devfreq governor
 789  * @governor:   the devfreq governor to be added
 790  */
 791 int devfreq_add_governor(struct devfreq_governor *governor)
 792 {
 793         struct devfreq_governor *g;
 794         struct devfreq *devfreq;
 795         int err = 0;
 796
 797         if (!governor) {
 798                 pr_err("%s: Invalid parameters.\n", __func__);
 799                 return -EINVAL;
 800         }
 801
 802         mutex_lock(&devfreq_list_lock);
 803         g = find_devfreq_governor(governor->name);
 804         if (!IS_ERR(g)) {
 805                 pr_err("%s: governor %s already registered\n", __func__,
 806                        g->name);
 807                 err = -EINVAL;
 808                 goto err_out;
 809         }
 810
 811         list_add(&governor->node, &devfreq_governor_list);
 812
 813         list_for_each_entry(devfreq, &devfreq_list, node) {
 814                 int ret = 0;
 815                 struct device *dev = devfreq->dev.parent;
 816
 817                 if (!strncmp(devfreq->governor_name, governor->name,
 818                              DEVFREQ_NAME_LEN)) {
 819                         /* The following should never occur */
 820                         if (devfreq->governor) {
 821                                 dev_warn(dev,
 822                                          "%s: Governor %s already present\n",
 823                                          __func__, devfreq->governor->name);
 824                                 ret = devfreq->governor->event_handler(devfreq,
 825                                                         DEVFREQ_GOV_STOP, NULL);
 826                                 if (ret) {
 827                                         dev_warn(dev,
 828                                                  "%s: Governor %s stop = %d\n",
 829                                                  __func__,
 830                                                  devfreq->governor->name, ret);
 831                                 }
 832                                 /* Fall through */
 833                         }
 834                         devfreq->governor = governor;
 835                         ret = devfreq->governor->event_handler(devfreq,
 836                                                 DEVFREQ_GOV_START, NULL);
 837                         if (ret) {
 838                                 dev_warn(dev, "%s: Governor %s start=%d\n",
 839                                          __func__, devfreq->governor->name,
 840                                          ret);
 841                         }
 842                 }
 843         }
 844
 845 err_out:
 846         mutex_unlock(&devfreq_list_lock);
 847
 848         return err;
 849 }
 850 EXPORT_SYMBOL(devfreq_add_governor);
 851
 852 /**
 853  * devfreq_remove_governor() - Remove devfreq feature from a device.
 854  * @governor:   the devfreq governor to be removed
 855  */
 856 int devfreq_remove_governor(struct devfreq_governor *governor)
 857 {
 858         struct devfreq_governor *g;
 859         struct devfreq *devfreq;
 860         int err = 0;
 861
 862         if (!governor) {
 863                 pr_err("%s: Invalid parameters.\n", __func__);
 864                 return -EINVAL;
 865         }
 866
 867         mutex_lock(&devfreq_list_lock);
 868         g = find_devfreq_governor(governor->name);
 869         if (IS_ERR(g)) {
 870                 pr_err("%s: governor %s not registered\n", __func__,
 871                        governor->name);
 872                 err = PTR_ERR(g);
 873                 goto err_out;
 874         }
 875         list_for_each_entry(devfreq, &devfreq_list, node) {
 876                 int ret;
 877                 struct device *dev = devfreq->dev.parent;
 878
 879                 if (!strncmp(devfreq->governor_name, governor->name,
 880                              DEVFREQ_NAME_LEN)) {
 881                         /* we should have a devfreq governor! */
 882                         if (!devfreq->governor) {
 883                                 dev_warn(dev, "%s: Governor %s NOT present\n",
 884                                          __func__, governor->name);
 885                                 continue;
 886                                 /* Fall through */
 887                         }
 888                         ret = devfreq->governor->event_handler(devfreq,
 889                                                 DEVFREQ_GOV_STOP, NULL);
 890                         if (ret) {
 891                                 dev_warn(dev, "%s: Governor %s stop=%d\n",
 892                                          __func__, devfreq->governor->name,
 893                                          ret);
 894                         }
 895                         devfreq->governor = NULL;
 896                 }
 897         }
 898
 899         list_del(&governor->node);
 900 err_out:
 901         mutex_unlock(&devfreq_list_lock);
 902
 903         return err;
 904 }
 905 EXPORT_SYMBOL(devfreq_remove_governor);
 906
 907 static ssize_t governor_show(struct device *dev,
 908                              struct device_attribute *attr, char *buf)
 909 {
 910         if (!to_devfreq(dev)->governor)
 911                 return -EINVAL;
 912
 913         return sprintf(buf, "%s\n", to_devfreq(dev)->governor->name);
 914 }
 915
 916 static ssize_t governor_store(struct device *dev, struct device_attribute *attr,
 917                               const char *buf, size_t count)
 918 {
 919         struct devfreq *df = to_devfreq(dev);
 920         int ret;
 921         char str_governor[DEVFREQ_NAME_LEN + 1];
 922         struct devfreq_governor *governor;
 923
 924         ret = sscanf(buf, "%" __stringify(DEVFREQ_NAME_LEN) "s", str_governor);
 925         if (ret != 1)
 926                 return -EINVAL;
 927
 928         mutex_lock(&devfreq_list_lock);
 929         governor = find_devfreq_governor(str_governor);
 930         if (IS_ERR(governor)) {
 931                 ret = PTR_ERR(governor);
 932                 goto out;
 933         }
 934         if (df->governor == governor) {
 935                 ret = 0;
 936                 goto out;
 937         }
 938
 939         if (df->governor) {
 940                 ret = df->governor->event_handler(df, DEVFREQ_GOV_STOP, NULL);
 941                 if (ret) {
 942                         dev_warn(dev, "%s: Governor %s not stopped(%d)\n",
 943                                  __func__, df->governor->name, ret);
 944                         goto out;
 945                 }
 946         }
 947         df->governor = governor;
 948         strncpy(df->governor_name, governor->name, DEVFREQ_NAME_LEN);
 949         ret = df->governor->event_handler(df, DEVFREQ_GOV_START, NULL);
 950         if (ret)
 951                 dev_warn(dev, "%s: Governor %s not started(%d)\n",
 952                          __func__, df->governor->name, ret);
 953 out:
 954         mutex_unlock(&devfreq_list_lock);
 955
 956         if (!ret)
 957                 ret = count;
 958         return ret;
 959 }
 960 static DEVICE_ATTR_RW(governor);
 961
 962 static ssize_t available_governors_show(struct device *d,
 963                                         struct device_attribute *attr,
 964                                         char *buf)
 965 {
 966         struct devfreq_governor *tmp_governor;
 967         ssize_t count = 0;
 968
 969         mutex_lock(&devfreq_list_lock);
 970         list_for_each_entry(tmp_governor, &devfreq_governor_list, node)
 971                 count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
 972                                    "%s ", tmp_governor->name);
 973         mutex_unlock(&devfreq_list_lock);
 974
 975         /* Truncate the trailing space */
 976         if (count)
 977                 count--;
 978
 979         count += sprintf(&buf[count], "\n");
 980
 981         return count;
 982 }
 983 static DEVICE_ATTR_RO(available_governors);
 984
 985 static ssize_t cur_freq_show(struct device *dev, struct device_attribute *attr,
 986                              char *buf)
 987 {
 988         unsigned long freq;
 989         struct devfreq *devfreq = to_devfreq(dev);
 990
 991         if (devfreq->profile->get_cur_freq &&
 992                 !devfreq->profile->get_cur_freq(devfreq->dev.parent, &freq))
 993                         return sprintf(buf, "%lu\n", freq);
 994
 995         return sprintf(buf, "%lu\n", devfreq->previous_freq);
 996 }
 997 static DEVICE_ATTR_RO(cur_freq);
 998
 999 static ssize_t target_freq_show(struct device *dev,
1000                                 struct device_attribute *attr, char *buf)
1001 {
1002         return sprintf(buf, "%lu\n", to_devfreq(dev)->previous_freq);
1003 }
1004 static DEVICE_ATTR_RO(target_freq);
1005
1006 static ssize_t polling_interval_show(struct device *dev,
1007                                      struct device_attribute *attr, char *buf)
1008 {
1009         return sprintf(buf, "%d\n", to_devfreq(dev)->profile->polling_ms);
1010 }
1011
1012 static ssize_t polling_interval_store(struct device *dev,
1013                                       struct device_attribute *attr,
1014                                       const char *buf, size_t count)
1015 {
1016         struct devfreq *df = to_devfreq(dev);
1017         unsigned int value;
1018         int ret;
1019
1020         if (!df->governor)
1021                 return -EINVAL;
1022
1023         ret = sscanf(buf, "%u", &value);
1024         if (ret != 1)
1025                 return -EINVAL;
1026
1027         df->governor->event_handler(df, DEVFREQ_GOV_INTERVAL, &value);
1028         ret = count;
1029
1030         return ret;
1031 }
1032 static DEVICE_ATTR_RW(polling_interval);
1033
1034 static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr,
1035                               const char *buf, size_t count)
1036 {
1037         struct devfreq *df = to_devfreq(dev);
1038         unsigned long value;
1039         int ret;
1040         unsigned long max;
1041
1042         ret = sscanf(buf, "%lu", &value);
1043         if (ret != 1)
1044                 return -EINVAL;
1045
1046         mutex_lock(&df->lock);
1047         max = df->max_freq;
1048         if (value && max && value > max) {
1049                 ret = -EINVAL;
1050                 goto unlock;
1051         }
1052
1053         df->min_freq = value;
1054         update_devfreq(df);
1055         ret = count;
1056 unlock:
1057         mutex_unlock(&df->lock);
1058         return ret;
1059 }
1060
1061 static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr,
1062                               const char *buf, size_t count)
1063 {
1064         struct devfreq *df = to_devfreq(dev);
1065         unsigned long value;
1066         int ret;
1067         unsigned long min;
1068
1069         ret = sscanf(buf, "%lu", &value);
1070         if (ret != 1)
1071                 return -EINVAL;
1072
1073         mutex_lock(&df->lock);
1074         min = df->min_freq;
1075         if (value && min && value < min) {
1076                 ret = -EINVAL;
1077                 goto unlock;
1078         }
1079
1080         df->max_freq = value;
1081         update_devfreq(df);
1082         ret = count;
1083 unlock:
1084         mutex_unlock(&df->lock);
1085         return ret;
1086 }
1087
1088 #define show_one(name)                                          \
1089 static ssize_t name##_show                                      \
1090 (struct device *dev, struct device_attribute *attr, char *buf)  \
1091 {                                                               \
1092         return sprintf(buf, "%lu\n", to_devfreq(dev)->name);    \
1093 }
1094 show_one(min_freq);
1095 show_one(max_freq);
1096
1097 static DEVICE_ATTR_RW(min_freq);
1098 static DEVICE_ATTR_RW(max_freq);
1099
1100 static ssize_t available_frequencies_show(struct device *d,
1101                                           struct device_attribute *attr,
1102                                           char *buf)
1103 {
1104         struct devfreq *df = to_devfreq(d);
1105         struct device *dev = df->dev.parent;
1106         struct dev_pm_opp *opp;
1107         ssize_t count = 0;
1108         unsigned long freq = 0;
1109
1110         rcu_read_lock();
1111         do {
1112                 opp = dev_pm_opp_find_freq_ceil(dev, &freq);
1113                 if (IS_ERR(opp))
1114                         break;
1115
1116                 count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
1117                                    "%lu ", freq);
1118                 freq++;
1119         } while (1);
1120         rcu_read_unlock();
1121
1122         /* Truncate the trailing space */
1123         if (count)
1124                 count--;
1125
1126         count += sprintf(&buf[count], "\n");
1127
1128         return count;
1129 }
1130 static DEVICE_ATTR_RO(available_frequencies);
1131
1132 static ssize_t trans_stat_show(struct device *dev,
1133                                struct device_attribute *attr, char *buf)
1134 {
1135         struct devfreq *devfreq = to_devfreq(dev);
1136         ssize_t len;
1137         int i, j;
1138         unsigned int max_state = devfreq->profile->max_state;
1139
1140         if (!devfreq->stop_polling &&
1141                         devfreq_update_status(devfreq, devfreq->previous_freq))
1142                 return 0;
1143         if (max_state == 0)
1144                 return sprintf(buf, "Not Supported.\n");
1145
1146         len = sprintf(buf, "     From  :   To\n");
1147         len += sprintf(buf + len, "           :");
1148         for (i = 0; i < max_state; i++)
1149                 len += sprintf(buf + len, "%10lu",
1150                                 devfreq->profile->freq_table[i]);
1151
1152         len += sprintf(buf + len, "   time(ms)\n");
1153
1154         for (i = 0; i < max_state; i++) {
1155                 if (devfreq->profile->freq_table[i]
1156                                         == devfreq->previous_freq) {
1157                         len += sprintf(buf + len, "*");
1158                 } else {
1159                         len += sprintf(buf + len, " ");
1160                 }
1161                 len += sprintf(buf + len, "%10lu:",
1162                                 devfreq->profile->freq_table[i]);
1163                 for (j = 0; j < max_state; j++)
1164                         len += sprintf(buf + len, "%10u",
1165                                 devfreq->trans_table[(i * max_state) + j]);
1166                 len += sprintf(buf + len, "%10u\n",
1167                         jiffies_to_msecs(devfreq->time_in_state[i]));
1168         }
1169
1170         len += sprintf(buf + len, "Total transition : %u\n",
1171                                         devfreq->total_trans);
1172         return len;
1173 }
1174 static DEVICE_ATTR_RO(trans_stat);
1175
1176 static struct attribute *devfreq_attrs[] = {
1177         &dev_attr_governor.attr,
1178         &dev_attr_available_governors.attr,
1179         &dev_attr_cur_freq.attr,
1180         &dev_attr_available_frequencies.attr,
1181         &dev_attr_target_freq.attr,
1182         &dev_attr_polling_interval.attr,
1183         &dev_attr_min_freq.attr,
1184         &dev_attr_max_freq.attr,
1185         &dev_attr_trans_stat.attr,
1186         NULL,
1187 };
1188 ATTRIBUTE_GROUPS(devfreq);
1189
1190 static int __init devfreq_init(void)
1191 {
1192         devfreq_class = class_create(THIS_MODULE, "devfreq");
1193         if (IS_ERR(devfreq_class)) {
1194                 pr_err("%s: couldn't create class\n", __FILE__);
1195                 return PTR_ERR(devfreq_class);
1196         }
1197
1198         devfreq_wq = create_freezable_workqueue("devfreq_wq");
1199         if (!devfreq_wq) {
1200                 class_destroy(devfreq_class);
1201                 pr_err("%s: couldn't create workqueue\n", __FILE__);
1202                 return -ENOMEM;
1203         }
1204         devfreq_class->dev_groups = devfreq_groups;
1205
1206         return 0;
1207 }
1208 subsys_initcall(devfreq_init);
1209
1210 /*
1211  * The followings are helper functions for devfreq user device drivers with
1212  * OPP framework.
1213  */
1214
1215 /**
1216  * devfreq_recommended_opp() - Helper function to get proper OPP for the
1217  *                           freq value given to target callback.
1218  * @dev:        The devfreq user device. (parent of devfreq)
1219  * @freq:       The frequency given to target function
1220  * @flags:      Flags handed from devfreq framework.
1221  *
1222  * Locking: This function must be called under rcu_read_lock(). opp is a rcu
1223  * protected pointer. The reason for the same is that the opp pointer which is
1224  * returned will remain valid for use with opp_get_{voltage, freq} only while
1225  * under the locked area. The pointer returned must be used prior to unlocking
1226  * with rcu_read_unlock() to maintain the integrity of the pointer.
1227  */
1228 struct dev_pm_opp *devfreq_recommended_opp(struct device *dev,
1229                                            unsigned long *freq,
1230                                            u32 flags)
1231 {
1232         struct dev_pm_opp *opp;
1233
1234         if (flags & DEVFREQ_FLAG_LEAST_UPPER_BOUND) {
1235                 /* The freq is an upper bound. opp should be lower */
1236                 opp = dev_pm_opp_find_freq_floor(dev, freq);
1237
1238                 /* If not available, use the closest opp */
1239                 if (opp == ERR_PTR(-ERANGE))
1240                         opp = dev_pm_opp_find_freq_ceil(dev, freq);
1241         } else {
1242                 /* The freq is an lower bound. opp should be higher */
1243                 opp = dev_pm_opp_find_freq_ceil(dev, freq);
1244
1245                 /* If not available, use the closest opp */
1246                 if (opp == ERR_PTR(-ERANGE))
1247                         opp = dev_pm_opp_find_freq_floor(dev, freq);
1248         }
1249
1250         return opp;
1251 }
1252 EXPORT_SYMBOL(devfreq_recommended_opp);
1253
1254 /**
1255  * devfreq_register_opp_notifier() - Helper function to get devfreq notified
1256  *                                 for any changes in the OPP availability
1257  *                                 changes
1258  * @dev:        The devfreq user device. (parent of devfreq)
1259  * @devfreq:    The devfreq object.
1260  */
1261 int devfreq_register_opp_notifier(struct device *dev, struct devfreq *devfreq)
1262 {
1263         struct srcu_notifier_head *nh;
1264         int ret = 0;
1265
1266         rcu_read_lock();
1267         nh = dev_pm_opp_get_notifier(dev);
1268         if (IS_ERR(nh))
1269                 ret = PTR_ERR(nh);
1270         rcu_read_unlock();
1271         if (!ret)
1272                 ret = srcu_notifier_chain_register(nh, &devfreq->nb);
1273
1274         return ret;
1275 }
1276 EXPORT_SYMBOL(devfreq_register_opp_notifier);
1277
1278 /**
1279  * devfreq_unregister_opp_notifier() - Helper function to stop getting devfreq
1280  *                                   notified for any changes in the OPP
1281  *                                   availability changes anymore.
1282  * @dev:        The devfreq user device. (parent of devfreq)
1283  * @devfreq:    The devfreq object.
1284  *
1285  * At exit() callback of devfreq_dev_profile, this must be included if
1286  * devfreq_recommended_opp is used.
1287  */
1288 int devfreq_unregister_opp_notifier(struct device *dev, struct devfreq *devfreq)
1289 {
1290         struct srcu_notifier_head *nh;
1291         int ret = 0;
1292
1293         rcu_read_lock();
1294         nh = dev_pm_opp_get_notifier(dev);
1295         if (IS_ERR(nh))
1296                 ret = PTR_ERR(nh);
1297         rcu_read_unlock();
1298         if (!ret)
1299                 ret = srcu_notifier_chain_unregister(nh, &devfreq->nb);
1300
1301         return ret;
1302 }
1303 EXPORT_SYMBOL(devfreq_unregister_opp_notifier);
1304
1305 static void devm_devfreq_opp_release(struct device *dev, void *res)
1306 {
1307         devfreq_unregister_opp_notifier(dev, *(struct devfreq **)res);
1308 }
1309
1310 /**
1311  * devm_ devfreq_register_opp_notifier()
1312  *              - Resource-managed devfreq_register_opp_notifier()
1313  * @dev:        The devfreq user device. (parent of devfreq)
1314  * @devfreq:    The devfreq object.
1315  */
1316 int devm_devfreq_register_opp_notifier(struct device *dev,
1317                                        struct devfreq *devfreq)
1318 {
1319         struct devfreq **ptr;
1320         int ret;
1321
1322         ptr = devres_alloc(devm_devfreq_opp_release, sizeof(*ptr), GFP_KERNEL);
1323         if (!ptr)
1324                 return -ENOMEM;
1325
1326         ret = devfreq_register_opp_notifier(dev, devfreq);
1327         if (ret) {
1328                 devres_free(ptr);
1329                 return ret;
1330         }
1331
1332         *ptr = devfreq;
1333         devres_add(dev, ptr);
1334
1335         return 0;
1336 }
1337 EXPORT_SYMBOL(devm_devfreq_register_opp_notifier);
1338
1339 /**
1340  * devm_devfreq_unregister_opp_notifier()
1341  *              - Resource-managed devfreq_unregister_opp_notifier()
1342  * @dev:        The devfreq user device. (parent of devfreq)
1343  * @devfreq:    The devfreq object.
1344  */
1345 void devm_devfreq_unregister_opp_notifier(struct device *dev,
1346                                          struct devfreq *devfreq)
1347 {
1348         WARN_ON(devres_release(dev, devm_devfreq_opp_release,
1349                                devm_devfreq_dev_match, devfreq));
1350 }
1351 EXPORT_SYMBOL(devm_devfreq_unregister_opp_notifier);
1352
1353 /**
1354  * devfreq_register_notifier() - Register a driver with devfreq
1355  * @devfreq:    The devfreq object.
1356  * @nb:         The notifier block to register.
1357  * @list:       DEVFREQ_TRANSITION_NOTIFIER.
1358  */
1359 int devfreq_register_notifier(struct devfreq *devfreq,
1360                                 struct notifier_block *nb,
1361                                 unsigned int list)
1362 {
1363         int ret = 0;
1364
1365         if (!devfreq)
1366                 return -EINVAL;
1367
1368         switch (list) {
1369         case DEVFREQ_TRANSITION_NOTIFIER:
1370                 ret = srcu_notifier_chain_register(
1371                                 &devfreq->transition_notifier_list, nb);
1372                 break;
1373         default:
1374                 ret = -EINVAL;
1375         }
1376
1377         return ret;
1378 }
1379 EXPORT_SYMBOL(devfreq_register_notifier);
1380
1381 /*
1382  * devfreq_unregister_notifier() - Unregister a driver with devfreq
1383  * @devfreq:    The devfreq object.
1384  * @nb:         The notifier block to be unregistered.
1385  * @list:       DEVFREQ_TRANSITION_NOTIFIER.
1386  */
1387 int devfreq_unregister_notifier(struct devfreq *devfreq,
1388                                 struct notifier_block *nb,
1389                                 unsigned int list)
1390 {
1391         int ret = 0;
1392
1393         if (!devfreq)
1394                 return -EINVAL;
1395
1396         switch (list) {
1397         case DEVFREQ_TRANSITION_NOTIFIER:
1398                 ret = srcu_notifier_chain_unregister(
1399                                 &devfreq->transition_notifier_list, nb);
1400                 break;
1401         default:
1402                 ret = -EINVAL;
1403         }
1404
1405         return ret;
1406 }
1407 EXPORT_SYMBOL(devfreq_unregister_notifier);
1408
1409 struct devfreq_notifier_devres {
1410         struct devfreq *devfreq;
1411         struct notifier_block *nb;
1412         unsigned int list;
1413 };
1414
1415 static void devm_devfreq_notifier_release(struct device *dev, void *res)
1416 {
1417         struct devfreq_notifier_devres *this = res;
1418
1419         devfreq_unregister_notifier(this->devfreq, this->nb, this->list);
1420 }
1421
1422 /**
1423  * devm_devfreq_register_notifier()
1424         - Resource-managed devfreq_register_notifier()
1425  * @dev:        The devfreq user device. (parent of devfreq)
1426  * @devfreq:    The devfreq object.
1427  * @nb:         The notifier block to be unregistered.
1428  * @list:       DEVFREQ_TRANSITION_NOTIFIER.
1429  */
1430 int devm_devfreq_register_notifier(struct device *dev,
1431                                 struct devfreq *devfreq,
1432                                 struct notifier_block *nb,
1433                                 unsigned int list)
1434 {
1435         struct devfreq_notifier_devres *ptr;
1436         int ret;
1437
1438         ptr = devres_alloc(devm_devfreq_notifier_release, sizeof(*ptr),
1439                                 GFP_KERNEL);
1440         if (!ptr)
1441                 return -ENOMEM;
1442
1443         ret = devfreq_register_notifier(devfreq, nb, list);
1444         if (ret) {
1445                 devres_free(ptr);
1446                 return ret;
1447         }
1448
1449         ptr->devfreq = devfreq;
1450         ptr->nb = nb;
1451         ptr->list = list;
1452         devres_add(dev, ptr);
1453
1454         return 0;
1455 }
1456 EXPORT_SYMBOL(devm_devfreq_register_notifier);
1457
1458 /**
1459  * devm_devfreq_unregister_notifier()
1460         - Resource-managed devfreq_unregister_notifier()
1461  * @dev:        The devfreq user device. (parent of devfreq)
1462  * @devfreq:    The devfreq object.
1463  * @nb:         The notifier block to be unregistered.
1464  * @list:       DEVFREQ_TRANSITION_NOTIFIER.
1465  */
1466 void devm_devfreq_unregister_notifier(struct device *dev,
1467                                 struct devfreq *devfreq,
1468                                 struct notifier_block *nb,
1469                                 unsigned int list)
1470 {
1471         WARN_ON(devres_release(dev, devm_devfreq_notifier_release,
1472                                devm_devfreq_dev_match, devfreq));
1473 }
1474 EXPORT_SYMBOL(devm_devfreq_unregister_notifier);