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