drivers/base/power/runtime.c

   1 /*
   2  * drivers/base/power/runtime.c - Helper functions for device runtime PM
   3  *
   4  * Copyright (c) 2009 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc.
   5  * Copyright (C) 2010 Alan Stern <stern@rowland.harvard.edu>
   6  *
   7  * This file is released under the GPLv2.
   8  */
   9
  10 #include <linux/sched.h>
  11 #include <linux/export.h>
  12 #include <linux/pm_runtime.h>
  13 #include <trace/events/rpm.h>
  14 #include "power.h"
  15
  16 static int rpm_resume(struct device *dev, int rpmflags);
  17 static int rpm_suspend(struct device *dev, int rpmflags);
  18
  19 /**
  20  * update_pm_runtime_accounting - Update the time accounting of power states
  21  * @dev: Device to update the accounting for
  22  *
  23  * In order to be able to have time accounting of the various power states
  24  * (as used by programs such as PowerTOP to show the effectiveness of runtime
  25  * PM), we need to track the time spent in each state.
  26  * update_pm_runtime_accounting must be called each time before the
  27  * runtime_status field is updated, to account the time in the old state
  28  * correctly.
  29  */
  30 void update_pm_runtime_accounting(struct device *dev)
  31 {
  32         unsigned long now = jiffies;
  33         unsigned long delta;
  34
  35         delta = now - dev->power.accounting_timestamp;
  36
  37         dev->power.accounting_timestamp = now;
  38
  39         if (dev->power.disable_depth > 0)
  40                 return;
  41
  42         if (dev->power.runtime_status == RPM_SUSPENDED)
  43                 dev->power.suspended_jiffies += delta;
  44         else
  45                 dev->power.active_jiffies += delta;
  46 }
  47
  48 static void __update_runtime_status(struct device *dev, enum rpm_status status)
  49 {
  50         update_pm_runtime_accounting(dev);
  51         dev->power.runtime_status = status;
  52 }
  53
  54 /**
  55  * pm_runtime_deactivate_timer - Deactivate given device's suspend timer.
  56  * @dev: Device to handle.
  57  */
  58 static void pm_runtime_deactivate_timer(struct device *dev)
  59 {
  60         if (dev->power.timer_expires > 0) {
  61                 del_timer(&dev->power.suspend_timer);
  62                 dev->power.timer_expires = 0;
  63         }
  64 }
  65
  66 /**
  67  * pm_runtime_cancel_pending - Deactivate suspend timer and cancel requests.
  68  * @dev: Device to handle.
  69  */
  70 static void pm_runtime_cancel_pending(struct device *dev)
  71 {
  72         pm_runtime_deactivate_timer(dev);
  73         /*
  74          * In case there's a request pending, make sure its work function will
  75          * return without doing anything.
  76          */
  77         dev->power.request = RPM_REQ_NONE;
  78 }
  79
  80 /*
  81  * pm_runtime_autosuspend_expiration - Get a device's autosuspend-delay expiration time.
  82  * @dev: Device to handle.
  83  *
  84  * Compute the autosuspend-delay expiration time based on the device's
  85  * power.last_busy time.  If the delay has already expired or is disabled
  86  * (negative) or the power.use_autosuspend flag isn't set, return 0.
  87  * Otherwise return the expiration time in jiffies (adjusted to be nonzero).
  88  *
  89  * This function may be called either with or without dev->power.lock held.
  90  * Either way it can be racy, since power.last_busy may be updated at any time.
  91  */
  92 unsigned long pm_runtime_autosuspend_expiration(struct device *dev)
  93 {
  94         int autosuspend_delay;
  95         long elapsed;
  96         unsigned long last_busy;
  97         unsigned long expires = 0;
  98
  99         if (!dev->power.use_autosuspend)
 100                 goto out;
 101
 102         autosuspend_delay = ACCESS_ONCE(dev->power.autosuspend_delay);
 103         if (autosuspend_delay < 0)
 104                 goto out;
 105
 106         last_busy = ACCESS_ONCE(dev->power.last_busy);
 107         elapsed = jiffies - last_busy;
 108         if (elapsed < 0)
 109                 goto out;       /* jiffies has wrapped around. */
 110
 111         /*
 112          * If the autosuspend_delay is >= 1 second, align the timer by rounding
 113          * up to the nearest second.
 114          */
 115         expires = last_busy + msecs_to_jiffies(autosuspend_delay);
 116         if (autosuspend_delay >= 1000)
 117                 expires = round_jiffies(expires);
 118         expires += !expires;
 119         if (elapsed >= expires - last_busy)
 120                 expires = 0;    /* Already expired. */
 121
 122  out:
 123         return expires;
 124 }
 125 EXPORT_SYMBOL_GPL(pm_runtime_autosuspend_expiration);
 126
 127 static int dev_memalloc_noio(struct device *dev, void *data)
 128 {
 129         return dev->power.memalloc_noio;
 130 }
 131
 132 /*
 133  * pm_runtime_set_memalloc_noio - Set a device's memalloc_noio flag.
 134  * @dev: Device to handle.
 135  * @enable: True for setting the flag and False for clearing the flag.
 136  *
 137  * Set the flag for all devices in the path from the device to the
 138  * root device in the device tree if @enable is true, otherwise clear
 139  * the flag for devices in the path whose siblings don't set the flag.
 140  *
 141  * The function should only be called by block device, or network
 142  * device driver for solving the deadlock problem during runtime
 143  * resume/suspend:
 144  *
 145  *     If memory allocation with GFP_KERNEL is called inside runtime
 146  *     resume/suspend callback of any one of its ancestors(or the
 147  *     block device itself), the deadlock may be triggered inside the
 148  *     memory allocation since it might not complete until the block
 149  *     device becomes active and the involed page I/O finishes. The
 150  *     situation is pointed out first by Alan Stern. Network device
 151  *     are involved in iSCSI kind of situation.
 152  *
 153  * The lock of dev_hotplug_mutex is held in the function for handling
 154  * hotplug race because pm_runtime_set_memalloc_noio() may be called
 155  * in async probe().
 156  *
 157  * The function should be called between device_add() and device_del()
 158  * on the affected device(block/network device).
 159  */
 160 void pm_runtime_set_memalloc_noio(struct device *dev, bool enable)
 161 {
 162         static DEFINE_MUTEX(dev_hotplug_mutex);
 163
 164         mutex_lock(&dev_hotplug_mutex);
 165         for (;;) {
 166                 bool enabled;
 167
 168                 /* hold power lock since bitfield is not SMP-safe. */
 169                 spin_lock_irq(&dev->power.lock);
 170                 enabled = dev->power.memalloc_noio;
 171                 dev->power.memalloc_noio = enable;
 172                 spin_unlock_irq(&dev->power.lock);
 173
 174                 /*
 175                  * not need to enable ancestors any more if the device
 176                  * has been enabled.
 177                  */
 178                 if (enabled && enable)
 179                         break;
 180
 181                 dev = dev->parent;
 182
 183                 /*
 184                  * clear flag of the parent device only if all the
 185                  * children don't set the flag because ancestor's
 186                  * flag was set by any one of the descendants.
 187                  */
 188                 if (!dev || (!enable &&
 189                              device_for_each_child(dev, NULL,
 190                                                    dev_memalloc_noio)))
 191                         break;
 192         }
 193         mutex_unlock(&dev_hotplug_mutex);
 194 }
 195 EXPORT_SYMBOL_GPL(pm_runtime_set_memalloc_noio);
 196
 197 /**
 198  * rpm_check_suspend_allowed - Test whether a device may be suspended.
 199  * @dev: Device to test.
 200  */
 201 static int rpm_check_suspend_allowed(struct device *dev)
 202 {
 203         int retval = 0;
 204
 205         if (dev->power.runtime_error)
 206                 retval = -EINVAL;
 207         else if (dev->power.disable_depth > 0)
 208                 retval = -EACCES;
 209         else if (atomic_read(&dev->power.usage_count) > 0)
 210                 retval = -EAGAIN;
 211         else if (!pm_children_suspended(dev))
 212                 retval = -EBUSY;
 213
 214         /* Pending resume requests take precedence over suspends. */
 215         else if ((dev->power.deferred_resume
 216                         && dev->power.runtime_status == RPM_SUSPENDING)
 217             || (dev->power.request_pending
 218                         && dev->power.request == RPM_REQ_RESUME))
 219                 retval = -EAGAIN;
 220         else if (__dev_pm_qos_read_value(dev) < 0)
 221                 retval = -EPERM;
 222         else if (dev->power.runtime_status == RPM_SUSPENDED)
 223                 retval = 1;
 224
 225         return retval;
 226 }
 227
 228 /**
 229  * __rpm_callback - Run a given runtime PM callback for a given device.
 230  * @cb: Runtime PM callback to run.
 231  * @dev: Device to run the callback for.
 232  */
 233 static int __rpm_callback(int (*cb)(struct device *), struct device *dev)
 234         __releases(&dev->power.lock) __acquires(&dev->power.lock)
 235 {
 236         int retval;
 237
 238         if (dev->power.irq_safe)
 239                 spin_unlock(&dev->power.lock);
 240         else
 241                 spin_unlock_irq(&dev->power.lock);
 242
 243         retval = cb(dev);
 244
 245         if (dev->power.irq_safe)
 246                 spin_lock(&dev->power.lock);
 247         else
 248                 spin_lock_irq(&dev->power.lock);
 249
 250         return retval;
 251 }
 252
 253 /**
 254  * rpm_idle - Notify device bus type if the device can be suspended.
 255  * @dev: Device to notify the bus type about.
 256  * @rpmflags: Flag bits.
 257  *
 258  * Check if the device's runtime PM status allows it to be suspended.  If
 259  * another idle notification has been started earlier, return immediately.  If
 260  * the RPM_ASYNC flag is set then queue an idle-notification request; otherwise
 261  * run the ->runtime_idle() callback directly.
 262  *
 263  * This function must be called under dev->power.lock with interrupts disabled.
 264  */
 265 static int rpm_idle(struct device *dev, int rpmflags)
 266 {
 267         int (*callback)(struct device *);
 268         int retval;
 269
 270         trace_rpm_idle(dev, rpmflags);
 271         retval = rpm_check_suspend_allowed(dev);
 272         if (retval < 0)
 273                 ;       /* Conditions are wrong. */
 274
 275         /* Idle notifications are allowed only in the RPM_ACTIVE state. */
 276         else if (dev->power.runtime_status != RPM_ACTIVE)
 277                 retval = -EAGAIN;
 278
 279         /*
 280          * Any pending request other than an idle notification takes
 281          * precedence over us, except that the timer may be running.
 282          */
 283         else if (dev->power.request_pending &&
 284             dev->power.request > RPM_REQ_IDLE)
 285                 retval = -EAGAIN;
 286
 287         /* Act as though RPM_NOWAIT is always set. */
 288         else if (dev->power.idle_notification)
 289                 retval = -EINPROGRESS;
 290         if (retval)
 291                 goto out;
 292
 293         /* Pending requests need to be canceled. */
 294         dev->power.request = RPM_REQ_NONE;
 295
 296         if (dev->power.no_callbacks) {
 297                 /* Assume ->runtime_idle() callback would have suspended. */
 298                 retval = rpm_suspend(dev, rpmflags);
 299                 goto out;
 300         }
 301
 302         /* Carry out an asynchronous or a synchronous idle notification. */
 303         if (rpmflags & RPM_ASYNC) {
 304                 dev->power.request = RPM_REQ_IDLE;
 305                 if (!dev->power.request_pending) {
 306                         dev->power.request_pending = true;
 307                         queue_work(pm_wq, &dev->power.work);
 308                 }
 309                 goto out;
 310         }
 311
 312         dev->power.idle_notification = true;
 313
 314         if (dev->pm_domain)
 315                 callback = dev->pm_domain->ops.runtime_idle;
 316         else if (dev->type && dev->type->pm)
 317                 callback = dev->type->pm->runtime_idle;
 318         else if (dev->class && dev->class->pm)
 319                 callback = dev->class->pm->runtime_idle;
 320         else if (dev->bus && dev->bus->pm)
 321                 callback = dev->bus->pm->runtime_idle;
 322         else
 323                 callback = NULL;
 324
 325         if (!callback && dev->driver && dev->driver->pm)
 326                 callback = dev->driver->pm->runtime_idle;
 327
 328         if (callback)
 329                 __rpm_callback(callback, dev);
 330
 331         dev->power.idle_notification = false;
 332         wake_up_all(&dev->power.wait_queue);
 333
 334  out:
 335         trace_rpm_return_int(dev, _THIS_IP_, retval);
 336         return retval;
 337 }
 338
 339 /**
 340  * rpm_callback - Run a given runtime PM callback for a given device.
 341  * @cb: Runtime PM callback to run.
 342  * @dev: Device to run the callback for.
 343  */
 344 static int rpm_callback(int (*cb)(struct device *), struct device *dev)
 345 {
 346         int retval;
 347
 348         if (!cb)
 349                 return -ENOSYS;
 350
 351         if (dev->power.memalloc_noio) {
 352                 unsigned int noio_flag;
 353
 354                 /*
 355                  * Deadlock might be caused if memory allocation with
 356                  * GFP_KERNEL happens inside runtime_suspend and
 357                  * runtime_resume callbacks of one block device's
 358                  * ancestor or the block device itself. Network
 359                  * device might be thought as part of iSCSI block
 360                  * device, so network device and its ancestor should
 361                  * be marked as memalloc_noio too.
 362                  */
 363                 noio_flag = memalloc_noio_save();
 364                 retval = __rpm_callback(cb, dev);
 365                 memalloc_noio_restore(noio_flag);
 366         } else {
 367                 retval = __rpm_callback(cb, dev);
 368         }
 369
 370         dev->power.runtime_error = retval;
 371         return retval != -EACCES ? retval : -EIO;
 372 }
 373
 374 /**
 375  * rpm_suspend - Carry out runtime suspend of given device.
 376  * @dev: Device to suspend.
 377  * @rpmflags: Flag bits.
 378  *
 379  * Check if the device's runtime PM status allows it to be suspended.
 380  * Cancel a pending idle notification, autosuspend or suspend. If
 381  * another suspend has been started earlier, either return immediately
 382  * or wait for it to finish, depending on the RPM_NOWAIT and RPM_ASYNC
 383  * flags. If the RPM_ASYNC flag is set then queue a suspend request;
 384  * otherwise run the ->runtime_suspend() callback directly. When
 385  * ->runtime_suspend succeeded, if a deferred resume was requested while
 386  * the callback was running then carry it out, otherwise send an idle
 387  * notification for its parent (if the suspend succeeded and both
 388  * ignore_children of parent->power and irq_safe of dev->power are not set).
 389  * If ->runtime_suspend failed with -EAGAIN or -EBUSY, and if the RPM_AUTO
 390  * flag is set and the next autosuspend-delay expiration time is in the
 391  * future, schedule another autosuspend attempt.
 392  *
 393  * This function must be called under dev->power.lock with interrupts disabled.
 394  */
 395 static int rpm_suspend(struct device *dev, int rpmflags)
 396         __releases(&dev->power.lock) __acquires(&dev->power.lock)
 397 {
 398         int (*callback)(struct device *);
 399         struct device *parent = NULL;
 400         int retval;
 401
 402         trace_rpm_suspend(dev, rpmflags);
 403
 404  repeat:
 405         retval = rpm_check_suspend_allowed(dev);
 406
 407         if (retval < 0)
 408                 ;       /* Conditions are wrong. */
 409
 410         /* Synchronous suspends are not allowed in the RPM_RESUMING state. */
 411         else if (dev->power.runtime_status == RPM_RESUMING &&
 412             !(rpmflags & RPM_ASYNC))
 413                 retval = -EAGAIN;
 414         if (retval)
 415                 goto out;
 416
 417         /* If the autosuspend_delay time hasn't expired yet, reschedule. */
 418         if ((rpmflags & RPM_AUTO)
 419             && dev->power.runtime_status != RPM_SUSPENDING) {
 420                 unsigned long expires = pm_runtime_autosuspend_expiration(dev);
 421
 422                 if (expires != 0) {
 423                         /* Pending requests need to be canceled. */
 424                         dev->power.request = RPM_REQ_NONE;
 425
 426                         /*
 427                          * Optimization: If the timer is already running and is
 428                          * set to expire at or before the autosuspend delay,
 429                          * avoid the overhead of resetting it.  Just let it
 430                          * expire; pm_suspend_timer_fn() will take care of the
 431                          * rest.
 432                          */
 433                         if (!(dev->power.timer_expires && time_before_eq(
 434                             dev->power.timer_expires, expires))) {
 435                                 dev->power.timer_expires = expires;
 436                                 mod_timer(&dev->power.suspend_timer, expires);
 437                         }
 438                         dev->power.timer_autosuspends = 1;
 439                         goto out;
 440                 }
 441         }
 442
 443         /* Other scheduled or pending requests need to be canceled. */
 444         pm_runtime_cancel_pending(dev);
 445
 446         if (dev->power.runtime_status == RPM_SUSPENDING) {
 447                 DEFINE_WAIT(wait);
 448
 449                 if (rpmflags & (RPM_ASYNC | RPM_NOWAIT)) {
 450                         retval = -EINPROGRESS;
 451                         goto out;
 452                 }
 453
 454                 if (dev->power.irq_safe) {
 455                         spin_unlock(&dev->power.lock);
 456
 457                         cpu_relax();
 458
 459                         spin_lock(&dev->power.lock);
 460                         goto repeat;
 461                 }
 462
 463                 /* Wait for the other suspend running in parallel with us. */
 464                 for (;;) {
 465                         prepare_to_wait(&dev->power.wait_queue, &wait,
 466                                         TASK_UNINTERRUPTIBLE);
 467                         if (dev->power.runtime_status != RPM_SUSPENDING)
 468                                 break;
 469
 470                         spin_unlock_irq(&dev->power.lock);
 471
 472                         schedule();
 473
 474                         spin_lock_irq(&dev->power.lock);
 475                 }
 476                 finish_wait(&dev->power.wait_queue, &wait);
 477                 goto repeat;
 478         }
 479
 480         if (dev->power.no_callbacks)
 481                 goto no_callback;       /* Assume success. */
 482
 483         /* Carry out an asynchronous or a synchronous suspend. */
 484         if (rpmflags & RPM_ASYNC) {
 485                 dev->power.request = (rpmflags & RPM_AUTO) ?
 486                     RPM_REQ_AUTOSUSPEND : RPM_REQ_SUSPEND;
 487                 if (!dev->power.request_pending) {
 488                         dev->power.request_pending = true;
 489                         queue_work(pm_wq, &dev->power.work);
 490                 }
 491                 goto out;
 492         }
 493
 494         __update_runtime_status(dev, RPM_SUSPENDING);
 495
 496         if (dev->pm_domain)
 497                 callback = dev->pm_domain->ops.runtime_suspend;
 498         else if (dev->type && dev->type->pm)
 499                 callback = dev->type->pm->runtime_suspend;
 500         else if (dev->class && dev->class->pm)
 501                 callback = dev->class->pm->runtime_suspend;
 502         else if (dev->bus && dev->bus->pm)
 503                 callback = dev->bus->pm->runtime_suspend;
 504         else
 505                 callback = NULL;
 506
 507         if (!callback && dev->driver && dev->driver->pm)
 508                 callback = dev->driver->pm->runtime_suspend;
 509
 510         retval = rpm_callback(callback, dev);
 511         if (retval)
 512                 goto fail;
 513
 514  no_callback:
 515         __update_runtime_status(dev, RPM_SUSPENDED);
 516         pm_runtime_deactivate_timer(dev);
 517
 518         if (dev->parent) {
 519                 parent = dev->parent;
 520                 atomic_add_unless(&parent->power.child_count, -1, 0);
 521         }
 522         wake_up_all(&dev->power.wait_queue);
 523
 524         if (dev->power.deferred_resume) {
 525                 dev->power.deferred_resume = false;
 526                 rpm_resume(dev, 0);
 527                 retval = -EAGAIN;
 528                 goto out;
 529         }
 530
 531         /* Maybe the parent is now able to suspend. */
 532         if (parent && !parent->power.ignore_children && !dev->power.irq_safe) {
 533                 spin_unlock(&dev->power.lock);
 534
 535                 spin_lock(&parent->power.lock);
 536                 rpm_idle(parent, RPM_ASYNC);
 537                 spin_unlock(&parent->power.lock);
 538
 539                 spin_lock(&dev->power.lock);
 540         }
 541
 542  out:
 543         trace_rpm_return_int(dev, _THIS_IP_, retval);
 544
 545         return retval;
 546
 547  fail:
 548         __update_runtime_status(dev, RPM_ACTIVE);
 549         dev->power.deferred_resume = false;
 550         wake_up_all(&dev->power.wait_queue);
 551
 552         if (retval == -EAGAIN || retval == -EBUSY) {
 553                 dev->power.runtime_error = 0;
 554
 555                 /*
 556                  * If the callback routine failed an autosuspend, and
 557                  * if the last_busy time has been updated so that there
 558                  * is a new autosuspend expiration time, automatically
 559                  * reschedule another autosuspend.
 560                  */
 561                 if ((rpmflags & RPM_AUTO) &&
 562                     pm_runtime_autosuspend_expiration(dev) != 0)
 563                         goto repeat;
 564         } else {
 565                 pm_runtime_cancel_pending(dev);
 566         }
 567         goto out;
 568 }
 569
 570 /**
 571  * rpm_resume - Carry out runtime resume of given device.
 572  * @dev: Device to resume.
 573  * @rpmflags: Flag bits.
 574  *
 575  * Check if the device's runtime PM status allows it to be resumed.  Cancel
 576  * any scheduled or pending requests.  If another resume has been started
 577  * earlier, either return immediately or wait for it to finish, depending on the
 578  * RPM_NOWAIT and RPM_ASYNC flags.  Similarly, if there's a suspend running in
 579  * parallel with this function, either tell the other process to resume after
 580  * suspending (deferred_resume) or wait for it to finish.  If the RPM_ASYNC
 581  * flag is set then queue a resume request; otherwise run the
 582  * ->runtime_resume() callback directly.  Queue an idle notification for the
 583  * device if the resume succeeded.
 584  *
 585  * This function must be called under dev->power.lock with interrupts disabled.
 586  */
 587 static int rpm_resume(struct device *dev, int rpmflags)
 588         __releases(&dev->power.lock) __acquires(&dev->power.lock)
 589 {
 590         int (*callback)(struct device *);
 591         struct device *parent = NULL;
 592         int retval = 0;
 593
 594         trace_rpm_resume(dev, rpmflags);
 595
 596  repeat:
 597         if (dev->power.runtime_error)
 598                 retval = -EINVAL;
 599         else if (dev->power.disable_depth == 1 && dev->power.is_suspended
 600             && dev->power.runtime_status == RPM_ACTIVE)
 601                 retval = 1;
 602         else if (dev->power.disable_depth > 0)
 603                 retval = -EACCES;
 604         if (retval)
 605                 goto out;
 606
 607         /*
 608          * Other scheduled or pending requests need to be canceled.  Small
 609          * optimization: If an autosuspend timer is running, leave it running
 610          * rather than cancelling it now only to restart it again in the near
 611          * future.
 612          */
 613         dev->power.request = RPM_REQ_NONE;
 614         if (!dev->power.timer_autosuspends)
 615                 pm_runtime_deactivate_timer(dev);
 616
 617         if (dev->power.runtime_status == RPM_ACTIVE) {
 618                 retval = 1;
 619                 goto out;
 620         }
 621
 622         if (dev->power.runtime_status == RPM_RESUMING
 623             || dev->power.runtime_status == RPM_SUSPENDING) {
 624                 DEFINE_WAIT(wait);
 625
 626                 if (rpmflags & (RPM_ASYNC | RPM_NOWAIT)) {
 627                         if (dev->power.runtime_status == RPM_SUSPENDING)
 628                                 dev->power.deferred_resume = true;
 629                         else
 630                                 retval = -EINPROGRESS;
 631                         goto out;
 632                 }
 633
 634                 if (dev->power.irq_safe) {
 635                         spin_unlock(&dev->power.lock);
 636
 637                         cpu_relax();
 638
 639                         spin_lock(&dev->power.lock);
 640                         goto repeat;
 641                 }
 642
 643                 /* Wait for the operation carried out in parallel with us. */
 644                 for (;;) {
 645                         prepare_to_wait(&dev->power.wait_queue, &wait,
 646                                         TASK_UNINTERRUPTIBLE);
 647                         if (dev->power.runtime_status != RPM_RESUMING
 648                             && dev->power.runtime_status != RPM_SUSPENDING)
 649                                 break;
 650
 651                         spin_unlock_irq(&dev->power.lock);
 652
 653                         schedule();
 654
 655                         spin_lock_irq(&dev->power.lock);
 656                 }
 657                 finish_wait(&dev->power.wait_queue, &wait);
 658                 goto repeat;
 659         }
 660
 661         /*
 662          * See if we can skip waking up the parent.  This is safe only if
 663          * power.no_callbacks is set, because otherwise we don't know whether
 664          * the resume will actually succeed.
 665          */
 666         if (dev->power.no_callbacks && !parent && dev->parent) {
 667                 spin_lock_nested(&dev->parent->power.lock, SINGLE_DEPTH_NESTING);
 668                 if (dev->parent->power.disable_depth > 0
 669                     || dev->parent->power.ignore_children
 670                     || dev->parent->power.runtime_status == RPM_ACTIVE) {
 671                         atomic_inc(&dev->parent->power.child_count);
 672                         spin_unlock(&dev->parent->power.lock);
 673                         retval = 1;
 674                         goto no_callback;       /* Assume success. */
 675                 }
 676                 spin_unlock(&dev->parent->power.lock);
 677         }
 678
 679         /* Carry out an asynchronous or a synchronous resume. */
 680         if (rpmflags & RPM_ASYNC) {
 681                 dev->power.request = RPM_REQ_RESUME;
 682                 if (!dev->power.request_pending) {
 683                         dev->power.request_pending = true;
 684                         queue_work(pm_wq, &dev->power.work);
 685                 }
 686                 retval = 0;
 687                 goto out;
 688         }
 689
 690         if (!parent && dev->parent) {
 691                 /*
 692                  * Increment the parent's usage counter and resume it if
 693                  * necessary.  Not needed if dev is irq-safe; then the
 694                  * parent is permanently resumed.
 695                  */
 696                 parent = dev->parent;
 697                 if (dev->power.irq_safe)
 698                         goto skip_parent;
 699                 spin_unlock(&dev->power.lock);
 700
 701                 pm_runtime_get_noresume(parent);
 702
 703                 spin_lock(&parent->power.lock);
 704                 /*
 705                  * We can resume if the parent's runtime PM is disabled or it
 706                  * is set to ignore children.
 707                  */
 708                 if (!parent->power.disable_depth
 709                     && !parent->power.ignore_children) {
 710                         rpm_resume(parent, 0);
 711                         if (parent->power.runtime_status != RPM_ACTIVE)
 712                                 retval = -EBUSY;
 713                 }
 714                 spin_unlock(&parent->power.lock);
 715
 716                 spin_lock(&dev->power.lock);
 717                 if (retval)
 718                         goto out;
 719                 goto repeat;
 720         }
 721  skip_parent:
 722
 723         if (dev->power.no_callbacks)
 724                 goto no_callback;       /* Assume success. */
 725
 726         __update_runtime_status(dev, RPM_RESUMING);
 727
 728         if (dev->pm_domain)
 729                 callback = dev->pm_domain->ops.runtime_resume;
 730         else if (dev->type && dev->type->pm)
 731                 callback = dev->type->pm->runtime_resume;
 732         else if (dev->class && dev->class->pm)
 733                 callback = dev->class->pm->runtime_resume;
 734         else if (dev->bus && dev->bus->pm)
 735                 callback = dev->bus->pm->runtime_resume;
 736         else
 737                 callback = NULL;
 738
 739         if (!callback && dev->driver && dev->driver->pm)
 740                 callback = dev->driver->pm->runtime_resume;
 741
 742         retval = rpm_callback(callback, dev);
 743         if (retval) {
 744                 __update_runtime_status(dev, RPM_SUSPENDED);
 745                 pm_runtime_cancel_pending(dev);
 746         } else {
 747  no_callback:
 748                 __update_runtime_status(dev, RPM_ACTIVE);
 749                 if (parent)
 750                         atomic_inc(&parent->power.child_count);
 751         }
 752         wake_up_all(&dev->power.wait_queue);
 753
 754         if (retval >= 0)
 755                 rpm_idle(dev, RPM_ASYNC);
 756
 757  out:
 758         if (parent && !dev->power.irq_safe) {
 759                 spin_unlock_irq(&dev->power.lock);
 760
 761                 pm_runtime_put(parent);
 762
 763                 spin_lock_irq(&dev->power.lock);
 764         }
 765
 766         trace_rpm_return_int(dev, _THIS_IP_, retval);
 767
 768         return retval;
 769 }
 770
 771 /**
 772  * pm_runtime_work - Universal runtime PM work function.
 773  * @work: Work structure used for scheduling the execution of this function.
 774  *
 775  * Use @work to get the device object the work is to be done for, determine what
 776  * is to be done and execute the appropriate runtime PM function.
 777  */
 778 static void pm_runtime_work(struct work_struct *work)
 779 {
 780         struct device *dev = container_of(work, struct device, power.work);
 781         enum rpm_request req;
 782
 783         spin_lock_irq(&dev->power.lock);
 784
 785         if (!dev->power.request_pending)
 786                 goto out;
 787
 788         req = dev->power.request;
 789         dev->power.request = RPM_REQ_NONE;
 790         dev->power.request_pending = false;
 791
 792         switch (req) {
 793         case RPM_REQ_NONE:
 794                 break;
 795         case RPM_REQ_IDLE:
 796                 rpm_idle(dev, RPM_NOWAIT);
 797                 break;
 798         case RPM_REQ_SUSPEND:
 799                 rpm_suspend(dev, RPM_NOWAIT);
 800                 break;
 801         case RPM_REQ_AUTOSUSPEND:
 802                 rpm_suspend(dev, RPM_NOWAIT | RPM_AUTO);
 803                 break;
 804         case RPM_REQ_RESUME:
 805                 rpm_resume(dev, RPM_NOWAIT);
 806                 break;
 807         }
 808
 809  out:
 810         spin_unlock_irq(&dev->power.lock);
 811 }
 812
 813 /**
 814  * pm_suspend_timer_fn - Timer function for pm_schedule_suspend().
 815  * @data: Device pointer passed by pm_schedule_suspend().
 816  *
 817  * Check if the time is right and queue a suspend request.
 818  */
 819 static void pm_suspend_timer_fn(unsigned long data)
 820 {
 821         struct device *dev = (struct device *)data;
 822         unsigned long flags;
 823         unsigned long expires;
 824
 825         spin_lock_irqsave(&dev->power.lock, flags);
 826
 827         expires = dev->power.timer_expires;
 828         /* If 'expire' is after 'jiffies' we've been called too early. */
 829         if (expires > 0 && !time_after(expires, jiffies)) {
 830                 dev->power.timer_expires = 0;
 831                 rpm_suspend(dev, dev->power.timer_autosuspends ?
 832                     (RPM_ASYNC | RPM_AUTO) : RPM_ASYNC);
 833         }
 834
 835         spin_unlock_irqrestore(&dev->power.lock, flags);
 836 }
 837
 838 /**
 839  * pm_schedule_suspend - Set up a timer to submit a suspend request in future.
 840  * @dev: Device to suspend.
 841  * @delay: Time to wait before submitting a suspend request, in milliseconds.
 842  */
 843 int pm_schedule_suspend(struct device *dev, unsigned int delay)
 844 {
 845         unsigned long flags;
 846         int retval;
 847
 848         spin_lock_irqsave(&dev->power.lock, flags);
 849
 850         if (!delay) {
 851                 retval = rpm_suspend(dev, RPM_ASYNC);
 852                 goto out;
 853         }
 854
 855         retval = rpm_check_suspend_allowed(dev);
 856         if (retval)
 857                 goto out;
 858
 859         /* Other scheduled or pending requests need to be canceled. */
 860         pm_runtime_cancel_pending(dev);
 861
 862         dev->power.timer_expires = jiffies + msecs_to_jiffies(delay);
 863         dev->power.timer_expires += !dev->power.timer_expires;
 864         dev->power.timer_autosuspends = 0;
 865         mod_timer(&dev->power.suspend_timer, dev->power.timer_expires);
 866
 867  out:
 868         spin_unlock_irqrestore(&dev->power.lock, flags);
 869
 870         return retval;
 871 }
 872 EXPORT_SYMBOL_GPL(pm_schedule_suspend);
 873
 874 /**
 875  * __pm_runtime_idle - Entry point for runtime idle operations.
 876  * @dev: Device to send idle notification for.
 877  * @rpmflags: Flag bits.
 878  *
 879  * If the RPM_GET_PUT flag is set, decrement the device's usage count and
 880  * return immediately if it is larger than zero.  Then carry out an idle
 881  * notification, either synchronous or asynchronous.
 882  *
 883  * This routine may be called in atomic context if the RPM_ASYNC flag is set,
 884  * or if pm_runtime_irq_safe() has been called.
 885  */
 886 int __pm_runtime_idle(struct device *dev, int rpmflags)
 887 {
 888         unsigned long flags;
 889         int retval;
 890
 891         might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe);
 892
 893         if (rpmflags & RPM_GET_PUT) {
 894                 if (!atomic_dec_and_test(&dev->power.usage_count))
 895                         return 0;
 896         }
 897
 898         spin_lock_irqsave(&dev->power.lock, flags);
 899         retval = rpm_idle(dev, rpmflags);
 900         spin_unlock_irqrestore(&dev->power.lock, flags);
 901
 902         return retval;
 903 }
 904 EXPORT_SYMBOL_GPL(__pm_runtime_idle);
 905
 906 /**
 907  * __pm_runtime_suspend - Entry point for runtime put/suspend operations.
 908  * @dev: Device to suspend.
 909  * @rpmflags: Flag bits.
 910  *
 911  * If the RPM_GET_PUT flag is set, decrement the device's usage count and
 912  * return immediately if it is larger than zero.  Then carry out a suspend,
 913  * either synchronous or asynchronous.
 914  *
 915  * This routine may be called in atomic context if the RPM_ASYNC flag is set,
 916  * or if pm_runtime_irq_safe() has been called.
 917  */
 918 int __pm_runtime_suspend(struct device *dev, int rpmflags)
 919 {
 920         unsigned long flags;
 921         int retval;
 922
 923         might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe);
 924
 925         if (rpmflags & RPM_GET_PUT) {
 926                 if (!atomic_dec_and_test(&dev->power.usage_count))
 927                         return 0;
 928         }
 929
 930         spin_lock_irqsave(&dev->power.lock, flags);
 931         retval = rpm_suspend(dev, rpmflags);
 932         spin_unlock_irqrestore(&dev->power.lock, flags);
 933
 934         return retval;
 935 }
 936 EXPORT_SYMBOL_GPL(__pm_runtime_suspend);
 937
 938 /**
 939  * __pm_runtime_resume - Entry point for runtime resume operations.
 940  * @dev: Device to resume.
 941  * @rpmflags: Flag bits.
 942  *
 943  * If the RPM_GET_PUT flag is set, increment the device's usage count.  Then
 944  * carry out a resume, either synchronous or asynchronous.
 945  *
 946  * This routine may be called in atomic context if the RPM_ASYNC flag is set,
 947  * or if pm_runtime_irq_safe() has been called.
 948  */
 949 int __pm_runtime_resume(struct device *dev, int rpmflags)
 950 {
 951         unsigned long flags;
 952         int retval;
 953
 954         might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe);
 955
 956         if (rpmflags & RPM_GET_PUT)
 957                 atomic_inc(&dev->power.usage_count);
 958
 959         spin_lock_irqsave(&dev->power.lock, flags);
 960         retval = rpm_resume(dev, rpmflags);
 961         spin_unlock_irqrestore(&dev->power.lock, flags);
 962
 963         return retval;
 964 }
 965 EXPORT_SYMBOL_GPL(__pm_runtime_resume);
 966
 967 /**
 968  * __pm_runtime_set_status - Set runtime PM status of a device.
 969  * @dev: Device to handle.
 970  * @status: New runtime PM status of the device.
 971  *
 972  * If runtime PM of the device is disabled or its power.runtime_error field is
 973  * different from zero, the status may be changed either to RPM_ACTIVE, or to
 974  * RPM_SUSPENDED, as long as that reflects the actual state of the device.
 975  * However, if the device has a parent and the parent is not active, and the
 976  * parent's power.ignore_children flag is unset, the device's status cannot be
 977  * set to RPM_ACTIVE, so -EBUSY is returned in that case.
 978  *
 979  * If successful, __pm_runtime_set_status() clears the power.runtime_error field
 980  * and the device parent's counter of unsuspended children is modified to
 981  * reflect the new status.  If the new status is RPM_SUSPENDED, an idle
 982  * notification request for the parent is submitted.
 983  */
 984 int __pm_runtime_set_status(struct device *dev, unsigned int status)
 985 {
 986         struct device *parent = dev->parent;
 987         unsigned long flags;
 988         bool notify_parent = false;
 989         int error = 0;
 990
 991         if (status != RPM_ACTIVE && status != RPM_SUSPENDED)
 992                 return -EINVAL;
 993
 994         spin_lock_irqsave(&dev->power.lock, flags);
 995
 996         if (!dev->power.runtime_error && !dev->power.disable_depth) {
 997                 error = -EAGAIN;
 998                 goto out;
 999         }
1000
1001         if (dev->power.runtime_status == status)
1002                 goto out_set;
1003
1004         if (status == RPM_SUSPENDED) {
1005                 /* It always is possible to set the status to 'suspended'. */
1006                 if (parent) {
1007                         atomic_add_unless(&parent->power.child_count, -1, 0);
1008                         notify_parent = !parent->power.ignore_children;
1009                 }
1010                 goto out_set;
1011         }
1012
1013         if (parent) {
1014                 spin_lock_nested(&parent->power.lock, SINGLE_DEPTH_NESTING);
1015
1016                 /*
1017                  * It is invalid to put an active child under a parent that is
1018                  * not active, has runtime PM enabled and the
1019                  * 'power.ignore_children' flag unset.
1020                  */
1021                 if (!parent->power.disable_depth
1022                     && !parent->power.ignore_children
1023                     && parent->power.runtime_status != RPM_ACTIVE)
1024                         error = -EBUSY;
1025                 else if (dev->power.runtime_status == RPM_SUSPENDED)
1026                         atomic_inc(&parent->power.child_count);
1027
1028                 spin_unlock(&parent->power.lock);
1029
1030                 if (error)
1031                         goto out;
1032         }
1033
1034  out_set:
1035         __update_runtime_status(dev, status);
1036         dev->power.runtime_error = 0;
1037  out:
1038         spin_unlock_irqrestore(&dev->power.lock, flags);
1039
1040         if (notify_parent)
1041                 pm_request_idle(parent);
1042
1043         return error;
1044 }
1045 EXPORT_SYMBOL_GPL(__pm_runtime_set_status);
1046
1047 /**
1048  * __pm_runtime_barrier - Cancel pending requests and wait for completions.
1049  * @dev: Device to handle.
1050  *
1051  * Flush all pending requests for the device from pm_wq and wait for all
1052  * runtime PM operations involving the device in progress to complete.
1053  *
1054  * Should be called under dev->power.lock with interrupts disabled.
1055  */
1056 static void __pm_runtime_barrier(struct device *dev)
1057 {
1058         pm_runtime_deactivate_timer(dev);
1059
1060         if (dev->power.request_pending) {
1061                 dev->power.request = RPM_REQ_NONE;
1062                 spin_unlock_irq(&dev->power.lock);
1063
1064                 cancel_work_sync(&dev->power.work);
1065
1066                 spin_lock_irq(&dev->power.lock);
1067                 dev->power.request_pending = false;
1068         }
1069
1070         if (dev->power.runtime_status == RPM_SUSPENDING
1071             || dev->power.runtime_status == RPM_RESUMING
1072             || dev->power.idle_notification) {
1073                 DEFINE_WAIT(wait);
1074
1075                 /* Suspend, wake-up or idle notification in progress. */
1076                 for (;;) {
1077                         prepare_to_wait(&dev->power.wait_queue, &wait,
1078                                         TASK_UNINTERRUPTIBLE);
1079                         if (dev->power.runtime_status != RPM_SUSPENDING
1080                             && dev->power.runtime_status != RPM_RESUMING
1081                             && !dev->power.idle_notification)
1082                                 break;
1083                         spin_unlock_irq(&dev->power.lock);
1084
1085                         schedule();
1086
1087                         spin_lock_irq(&dev->power.lock);
1088                 }
1089                 finish_wait(&dev->power.wait_queue, &wait);
1090         }
1091 }
1092
1093 /**
1094  * pm_runtime_barrier - Flush pending requests and wait for completions.
1095  * @dev: Device to handle.
1096  *
1097  * Prevent the device from being suspended by incrementing its usage counter and
1098  * if there's a pending resume request for the device, wake the device up.
1099  * Next, make sure that all pending requests for the device have been flushed
1100  * from pm_wq and wait for all runtime PM operations involving the device in
1101  * progress to complete.
1102  *
1103  * Return value:
1104  * 1, if there was a resume request pending and the device had to be woken up,
1105  * 0, otherwise
1106  */
1107 int pm_runtime_barrier(struct device *dev)
1108 {
1109         int retval = 0;
1110
1111         pm_runtime_get_noresume(dev);
1112         spin_lock_irq(&dev->power.lock);
1113
1114         if (dev->power.request_pending
1115             && dev->power.request == RPM_REQ_RESUME) {
1116                 rpm_resume(dev, 0);
1117                 retval = 1;
1118         }
1119
1120         __pm_runtime_barrier(dev);
1121
1122         spin_unlock_irq(&dev->power.lock);
1123         pm_runtime_put_noidle(dev);
1124
1125         return retval;
1126 }
1127 EXPORT_SYMBOL_GPL(pm_runtime_barrier);
1128
1129 /**
1130  * __pm_runtime_disable - Disable runtime PM of a device.
1131  * @dev: Device to handle.
1132  * @check_resume: If set, check if there's a resume request for the device.
1133  *
1134  * Increment power.disable_depth for the device and if was zero previously,
1135  * cancel all pending runtime PM requests for the device and wait for all
1136  * operations in progress to complete.  The device can be either active or
1137  * suspended after its runtime PM has been disabled.
1138  *
1139  * If @check_resume is set and there's a resume request pending when
1140  * __pm_runtime_disable() is called and power.disable_depth is zero, the
1141  * function will wake up the device before disabling its runtime PM.
1142  */
1143 void __pm_runtime_disable(struct device *dev, bool check_resume)
1144 {
1145         spin_lock_irq(&dev->power.lock);
1146
1147         if (dev->power.disable_depth > 0) {
1148                 dev->power.disable_depth++;
1149                 goto out;
1150         }
1151
1152         /*
1153          * Wake up the device if there's a resume request pending, because that
1154          * means there probably is some I/O to process and disabling runtime PM
1155          * shouldn't prevent the device from processing the I/O.
1156          */
1157         if (check_resume && dev->power.request_pending
1158             && dev->power.request == RPM_REQ_RESUME) {
1159                 /*
1160                  * Prevent suspends and idle notifications from being carried
1161                  * out after we have woken up the device.
1162                  */
1163                 pm_runtime_get_noresume(dev);
1164
1165                 rpm_resume(dev, 0);
1166
1167                 pm_runtime_put_noidle(dev);
1168         }
1169
1170         if (!dev->power.disable_depth++)
1171                 __pm_runtime_barrier(dev);
1172
1173  out:
1174         spin_unlock_irq(&dev->power.lock);
1175 }
1176 EXPORT_SYMBOL_GPL(__pm_runtime_disable);
1177
1178 /**
1179  * pm_runtime_enable - Enable runtime PM of a device.
1180  * @dev: Device to handle.
1181  */
1182 void pm_runtime_enable(struct device *dev)
1183 {
1184         unsigned long flags;
1185
1186         spin_lock_irqsave(&dev->power.lock, flags);
1187
1188         if (dev->power.disable_depth > 0)
1189                 dev->power.disable_depth--;
1190         else
1191                 dev_warn(dev, "Unbalanced %s!\n", __func__);
1192
1193         spin_unlock_irqrestore(&dev->power.lock, flags);
1194 }
1195 EXPORT_SYMBOL_GPL(pm_runtime_enable);
1196
1197 /**
1198  * pm_runtime_forbid - Block runtime PM of a device.
1199  * @dev: Device to handle.
1200  *
1201  * Increase the device's usage count and clear its power.runtime_auto flag,
1202  * so that it cannot be suspended at run time until pm_runtime_allow() is called
1203  * for it.
1204  */
1205 void pm_runtime_forbid(struct device *dev)
1206 {
1207         spin_lock_irq(&dev->power.lock);
1208         if (!dev->power.runtime_auto)
1209                 goto out;
1210
1211         dev->power.runtime_auto = false;
1212         atomic_inc(&dev->power.usage_count);
1213         rpm_resume(dev, 0);
1214
1215  out:
1216         spin_unlock_irq(&dev->power.lock);
1217 }
1218 EXPORT_SYMBOL_GPL(pm_runtime_forbid);
1219
1220 /**
1221  * pm_runtime_allow - Unblock runtime PM of a device.
1222  * @dev: Device to handle.
1223  *
1224  * Decrease the device's usage count and set its power.runtime_auto flag.
1225  */
1226 void pm_runtime_allow(struct device *dev)
1227 {
1228         spin_lock_irq(&dev->power.lock);
1229         if (dev->power.runtime_auto)
1230                 goto out;
1231
1232         dev->power.runtime_auto = true;
1233         if (atomic_dec_and_test(&dev->power.usage_count))
1234                 rpm_idle(dev, RPM_AUTO);
1235
1236  out:
1237         spin_unlock_irq(&dev->power.lock);
1238 }
1239 EXPORT_SYMBOL_GPL(pm_runtime_allow);
1240
1241 /**
1242  * pm_runtime_no_callbacks - Ignore runtime PM callbacks for a device.
1243  * @dev: Device to handle.
1244  *
1245  * Set the power.no_callbacks flag, which tells the PM core that this
1246  * device is power-managed through its parent and has no runtime PM
1247  * callbacks of its own.  The runtime sysfs attributes will be removed.
1248  */
1249 void pm_runtime_no_callbacks(struct device *dev)
1250 {
1251         spin_lock_irq(&dev->power.lock);
1252         dev->power.no_callbacks = 1;
1253         spin_unlock_irq(&dev->power.lock);
1254         if (device_is_registered(dev))
1255                 rpm_sysfs_remove(dev);
1256 }
1257 EXPORT_SYMBOL_GPL(pm_runtime_no_callbacks);
1258
1259 /**
1260  * pm_runtime_irq_safe - Leave interrupts disabled during callbacks.
1261  * @dev: Device to handle
1262  *
1263  * Set the power.irq_safe flag, which tells the PM core that the
1264  * ->runtime_suspend() and ->runtime_resume() callbacks for this device should
1265  * always be invoked with the spinlock held and interrupts disabled.  It also
1266  * causes the parent's usage counter to be permanently incremented, preventing
1267  * the parent from runtime suspending -- otherwise an irq-safe child might have
1268  * to wait for a non-irq-safe parent.
1269  */
1270 void pm_runtime_irq_safe(struct device *dev)
1271 {
1272         if (dev->parent)
1273                 pm_runtime_get_sync(dev->parent);
1274         spin_lock_irq(&dev->power.lock);
1275         dev->power.irq_safe = 1;
1276         spin_unlock_irq(&dev->power.lock);
1277 }
1278 EXPORT_SYMBOL_GPL(pm_runtime_irq_safe);
1279
1280 /**
1281  * update_autosuspend - Handle a change to a device's autosuspend settings.
1282  * @dev: Device to handle.
1283  * @old_delay: The former autosuspend_delay value.
1284  * @old_use: The former use_autosuspend value.
1285  *
1286  * Prevent runtime suspend if the new delay is negative and use_autosuspend is
1287  * set; otherwise allow it.  Send an idle notification if suspends are allowed.
1288  *
1289  * This function must be called under dev->power.lock with interrupts disabled.
1290  */
1291 static void update_autosuspend(struct device *dev, int old_delay, int old_use)
1292 {
1293         int delay = dev->power.autosuspend_delay;
1294
1295         /* Should runtime suspend be prevented now? */
1296         if (dev->power.use_autosuspend && delay < 0) {
1297
1298                 /* If it used to be allowed then prevent it. */
1299                 if (!old_use || old_delay >= 0) {
1300                         atomic_inc(&dev->power.usage_count);
1301                         rpm_resume(dev, 0);
1302                 }
1303         }
1304
1305         /* Runtime suspend should be allowed now. */
1306         else {
1307
1308                 /* If it used to be prevented then allow it. */
1309                 if (old_use && old_delay < 0)
1310                         atomic_dec(&dev->power.usage_count);
1311
1312                 /* Maybe we can autosuspend now. */
1313                 rpm_idle(dev, RPM_AUTO);
1314         }
1315 }
1316
1317 /**
1318  * pm_runtime_set_autosuspend_delay - Set a device's autosuspend_delay value.
1319  * @dev: Device to handle.
1320  * @delay: Value of the new delay in milliseconds.
1321  *
1322  * Set the device's power.autosuspend_delay value.  If it changes to negative
1323  * and the power.use_autosuspend flag is set, prevent runtime suspends.  If it
1324  * changes the other way, allow runtime suspends.
1325  */
1326 void pm_runtime_set_autosuspend_delay(struct device *dev, int delay)
1327 {
1328         int old_delay, old_use;
1329
1330         spin_lock_irq(&dev->power.lock);
1331         old_delay = dev->power.autosuspend_delay;
1332         old_use = dev->power.use_autosuspend;
1333         dev->power.autosuspend_delay = delay;
1334         update_autosuspend(dev, old_delay, old_use);
1335         spin_unlock_irq(&dev->power.lock);
1336 }
1337 EXPORT_SYMBOL_GPL(pm_runtime_set_autosuspend_delay);
1338
1339 /**
1340  * __pm_runtime_use_autosuspend - Set a device's use_autosuspend flag.
1341  * @dev: Device to handle.
1342  * @use: New value for use_autosuspend.
1343  *
1344  * Set the device's power.use_autosuspend flag, and allow or prevent runtime
1345  * suspends as needed.
1346  */
1347 void __pm_runtime_use_autosuspend(struct device *dev, bool use)
1348 {
1349         int old_delay, old_use;
1350
1351         spin_lock_irq(&dev->power.lock);
1352         old_delay = dev->power.autosuspend_delay;
1353         old_use = dev->power.use_autosuspend;
1354         dev->power.use_autosuspend = use;
1355         update_autosuspend(dev, old_delay, old_use);
1356         spin_unlock_irq(&dev->power.lock);
1357 }
1358 EXPORT_SYMBOL_GPL(__pm_runtime_use_autosuspend);
1359
1360 /**
1361  * pm_runtime_init - Initialize runtime PM fields in given device object.
1362  * @dev: Device object to initialize.
1363  */
1364 void pm_runtime_init(struct device *dev)
1365 {
1366         dev->power.runtime_status = RPM_SUSPENDED;
1367         dev->power.idle_notification = false;
1368
1369         dev->power.disable_depth = 1;
1370         atomic_set(&dev->power.usage_count, 0);
1371
1372         dev->power.runtime_error = 0;
1373
1374         atomic_set(&dev->power.child_count, 0);
1375         pm_suspend_ignore_children(dev, false);
1376         dev->power.runtime_auto = true;
1377
1378         dev->power.request_pending = false;
1379         dev->power.request = RPM_REQ_NONE;
1380         dev->power.deferred_resume = false;
1381         dev->power.accounting_timestamp = jiffies;
1382         INIT_WORK(&dev->power.work, pm_runtime_work);
1383
1384         dev->power.timer_expires = 0;
1385         setup_timer(&dev->power.suspend_timer, pm_suspend_timer_fn,
1386                         (unsigned long)dev);
1387
1388         init_waitqueue_head(&dev->power.wait_queue);
1389 }
1390
1391 /**
1392  * pm_runtime_remove - Prepare for removing a device from device hierarchy.
1393  * @dev: Device object being removed from device hierarchy.
1394  */
1395 void pm_runtime_remove(struct device *dev)
1396 {
1397         __pm_runtime_disable(dev, false);
1398
1399         /* Change the status back to 'suspended' to match the initial status. */
1400         if (dev->power.runtime_status == RPM_ACTIVE)
1401                 pm_runtime_set_suspended(dev);
1402         if (dev->power.irq_safe && dev->parent)
1403                 pm_runtime_put(dev->parent);
1404 }