kernel/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 typedef int (*pm_callback_t)(struct device *);
  17
  18 static pm_callback_t __rpm_get_callback(struct device *dev, size_t cb_offset)
  19 {
  20         pm_callback_t cb;
  21         const struct dev_pm_ops *ops;
  22
  23         if (dev->pm_domain)
  24                 ops = &dev->pm_domain->ops;
  25         else if (dev->type && dev->type->pm)
  26                 ops = dev->type->pm;
  27         else if (dev->class && dev->class->pm)
  28                 ops = dev->class->pm;
  29         else if (dev->bus && dev->bus->pm)
  30                 ops = dev->bus->pm;
  31         else
  32                 ops = NULL;
  33
  34         if (ops)
  35                 cb = *(pm_callback_t *)((void *)ops + cb_offset);
  36         else
  37                 cb = NULL;
  38
  39         if (!cb && dev->driver && dev->driver->pm)
  40                 cb = *(pm_callback_t *)((void *)dev->driver->pm + cb_offset);
  41
  42         return cb;
  43 }
  44
  45 #define RPM_GET_CALLBACK(dev, callback) \
  46                 __rpm_get_callback(dev, offsetof(struct dev_pm_ops, callback))
  47
  48 static int rpm_resume(struct device *dev, int rpmflags);
  49 static int rpm_suspend(struct device *dev, int rpmflags);
  50
  51 /**
  52  * update_pm_runtime_accounting - Update the time accounting of power states
  53  * @dev: Device to update the accounting for
  54  *
  55  * In order to be able to have time accounting of the various power states
  56  * (as used by programs such as PowerTOP to show the effectiveness of runtime
  57  * PM), we need to track the time spent in each state.
  58  * update_pm_runtime_accounting must be called each time before the
  59  * runtime_status field is updated, to account the time in the old state
  60  * correctly.
  61  */
  62 void update_pm_runtime_accounting(struct device *dev)
  63 {
  64         unsigned long now = jiffies;
  65         unsigned long delta;
  66
  67         delta = now - dev->power.accounting_timestamp;
  68
  69         dev->power.accounting_timestamp = now;
  70
  71         if (dev->power.disable_depth > 0)
  72                 return;
  73
  74         if (dev->power.runtime_status == RPM_SUSPENDED)
  75                 dev->power.suspended_jiffies += delta;
  76         else
  77                 dev->power.active_jiffies += delta;
  78 }
  79
  80 static void __update_runtime_status(struct device *dev, enum rpm_status status)
  81 {
  82         update_pm_runtime_accounting(dev);
  83         dev->power.runtime_status = status;
  84 }
  85
  86 /**
  87  * pm_runtime_deactivate_timer - Deactivate given device's suspend timer.
  88  * @dev: Device to handle.
  89  */
  90 static void pm_runtime_deactivate_timer(struct device *dev)
  91 {
  92         if (dev->power.timer_expires > 0) {
  93                 del_timer(&dev->power.suspend_timer);
  94                 dev->power.timer_expires = 0;
  95         }
  96 }
  97
  98 /**
  99  * pm_runtime_cancel_pending - Deactivate suspend timer and cancel requests.
 100  * @dev: Device to handle.
 101  */
 102 static void pm_runtime_cancel_pending(struct device *dev)
 103 {
 104         pm_runtime_deactivate_timer(dev);
 105         /*
 106          * In case there's a request pending, make sure its work function will
 107          * return without doing anything.
 108          */
 109         dev->power.request = RPM_REQ_NONE;
 110 }
 111
 112 /*
 113  * pm_runtime_autosuspend_expiration - Get a device's autosuspend-delay expiration time.
 114  * @dev: Device to handle.
 115  *
 116  * Compute the autosuspend-delay expiration time based on the device's
 117  * power.last_busy time.  If the delay has already expired or is disabled
 118  * (negative) or the power.use_autosuspend flag isn't set, return 0.
 119  * Otherwise return the expiration time in jiffies (adjusted to be nonzero).
 120  *
 121  * This function may be called either with or without dev->power.lock held.
 122  * Either way it can be racy, since power.last_busy may be updated at any time.
 123  */
 124 unsigned long pm_runtime_autosuspend_expiration(struct device *dev)
 125 {
 126         int autosuspend_delay;
 127         long elapsed;
 128         unsigned long last_busy;
 129         unsigned long expires = 0;
 130
 131         if (!dev->power.use_autosuspend)
 132                 goto out;
 133
 134         autosuspend_delay = ACCESS_ONCE(dev->power.autosuspend_delay);
 135         if (autosuspend_delay < 0)
 136                 goto out;
 137
 138         last_busy = ACCESS_ONCE(dev->power.last_busy);
 139         elapsed = jiffies - last_busy;
 140         if (elapsed < 0)
 141                 goto out;       /* jiffies has wrapped around. */
 142
 143         /*
 144          * If the autosuspend_delay is >= 1 second, align the timer by rounding
 145          * up to the nearest second.
 146          */
 147         expires = last_busy + msecs_to_jiffies(autosuspend_delay);
 148         if (autosuspend_delay >= 1000)
 149                 expires = round_jiffies(expires);
 150         expires += !expires;
 151         if (elapsed >= expires - last_busy)
 152                 expires = 0;    /* Already expired. */
 153
 154  out:
 155         return expires;
 156 }
 157 EXPORT_SYMBOL_GPL(pm_runtime_autosuspend_expiration);
 158
 159 static int dev_memalloc_noio(struct device *dev, void *data)
 160 {
 161         return dev->power.memalloc_noio;
 162 }
 163
 164 /*
 165  * pm_runtime_set_memalloc_noio - Set a device's memalloc_noio flag.
 166  * @dev: Device to handle.
 167  * @enable: True for setting the flag and False for clearing the flag.
 168  *
 169  * Set the flag for all devices in the path from the device to the
 170  * root device in the device tree if @enable is true, otherwise clear
 171  * the flag for devices in the path whose siblings don't set the flag.
 172  *
 173  * The function should only be called by block device, or network
 174  * device driver for solving the deadlock problem during runtime
 175  * resume/suspend:
 176  *
 177  *     If memory allocation with GFP_KERNEL is called inside runtime
 178  *     resume/suspend callback of any one of its ancestors(or the
 179  *     block device itself), the deadlock may be triggered inside the
 180  *     memory allocation since it might not complete until the block
 181  *     device becomes active and the involed page I/O finishes. The
 182  *     situation is pointed out first by Alan Stern. Network device
 183  *     are involved in iSCSI kind of situation.
 184  *
 185  * The lock of dev_hotplug_mutex is held in the function for handling
 186  * hotplug race because pm_runtime_set_memalloc_noio() may be called
 187  * in async probe().
 188  *
 189  * The function should be called between device_add() and device_del()
 190  * on the affected device(block/network device).
 191  */
 192 void pm_runtime_set_memalloc_noio(struct device *dev, bool enable)
 193 {
 194         static DEFINE_MUTEX(dev_hotplug_mutex);
 195
 196         mutex_lock(&dev_hotplug_mutex);
 197         for (;;) {
 198                 bool enabled;
 199
 200                 /* hold power lock since bitfield is not SMP-safe. */
 201                 spin_lock_irq(&dev->power.lock);
 202                 enabled = dev->power.memalloc_noio;
 203                 dev->power.memalloc_noio = enable;
 204                 spin_unlock_irq(&dev->power.lock);
 205
 206                 /*
 207                  * not need to enable ancestors any more if the device
 208                  * has been enabled.
 209                  */
 210                 if (enabled && enable)
 211                         break;
 212
 213                 dev = dev->parent;
 214
 215                 /*
 216                  * clear flag of the parent device only if all the
 217                  * children don't set the flag because ancestor's
 218                  * flag was set by any one of the descendants.
 219                  */
 220                 if (!dev || (!enable &&
 221                              device_for_each_child(dev, NULL,
 222                                                    dev_memalloc_noio)))
 223                         break;
 224         }
 225         mutex_unlock(&dev_hotplug_mutex);
 226 }
 227 EXPORT_SYMBOL_GPL(pm_runtime_set_memalloc_noio);
 228
 229 /**
 230  * rpm_check_suspend_allowed - Test whether a device may be suspended.
 231  * @dev: Device to test.
 232  */
 233 static int rpm_check_suspend_allowed(struct device *dev)
 234 {
 235         int retval = 0;
 236
 237         if (dev->power.runtime_error)
 238                 retval = -EINVAL;
 239         else if (dev->power.disable_depth > 0)
 240                 retval = -EACCES;
 241         else if (atomic_read(&dev->power.usage_count) > 0)
 242                 retval = -EAGAIN;
 243         else if (!pm_children_suspended(dev))
 244                 retval = -EBUSY;
 245
 246         /* Pending resume requests take precedence over suspends. */
 247         else if ((dev->power.deferred_resume
 248                         && dev->power.runtime_status == RPM_SUSPENDING)
 249             || (dev->power.request_pending
 250                         && dev->power.request == RPM_REQ_RESUME))
 251                 retval = -EAGAIN;
 252         else if (__dev_pm_qos_read_value(dev) < 0)
 253                 retval = -EPERM;
 254         else if (dev->power.runtime_status == RPM_SUSPENDED)
 255                 retval = 1;
 256
 257         return retval;
 258 }
 259
 260 /**
 261  * __rpm_callback - Run a given runtime PM callback for a given device.
 262  * @cb: Runtime PM callback to run.
 263  * @dev: Device to run the callback for.
 264  */
 265 static int __rpm_callback(int (*cb)(struct device *), struct device *dev)
 266         __releases(&dev->power.lock) __acquires(&dev->power.lock)
 267 {
 268         int retval;
 269
 270         if (dev->power.irq_safe)
 271                 spin_unlock(&dev->power.lock);
 272         else
 273                 spin_unlock_irq(&dev->power.lock);
 274
 275         retval = cb(dev);
 276
 277         if (dev->power.irq_safe)
 278                 spin_lock(&dev->power.lock);
 279         else
 280                 spin_lock_irq(&dev->power.lock);
 281
 282         return retval;
 283 }
 284
 285 /**
 286  * rpm_idle - Notify device bus type if the device can be suspended.
 287  * @dev: Device to notify the bus type about.
 288  * @rpmflags: Flag bits.
 289  *
 290  * Check if the device's runtime PM status allows it to be suspended.  If
 291  * another idle notification has been started earlier, return immediately.  If
 292  * the RPM_ASYNC flag is set then queue an idle-notification request; otherwise
 293  * run the ->runtime_idle() callback directly. If the ->runtime_idle callback
 294  * doesn't exist or if it returns 0, call rpm_suspend with the RPM_AUTO flag.
 295  *
 296  * This function must be called under dev->power.lock with interrupts disabled.
 297  */
 298 static int rpm_idle(struct device *dev, int rpmflags)
 299 {
 300         int (*callback)(struct device *);
 301         int retval;
 302
 303         trace_rpm_idle(dev, rpmflags);
 304         retval = rpm_check_suspend_allowed(dev);
 305         if (retval < 0)
 306                 ;       /* Conditions are wrong. */
 307
 308         /* Idle notifications are allowed only in the RPM_ACTIVE state. */
 309         else if (dev->power.runtime_status != RPM_ACTIVE)
 310                 retval = -EAGAIN;
 311
 312         /*
 313          * Any pending request other than an idle notification takes
 314          * precedence over us, except that the timer may be running.
 315          */
 316         else if (dev->power.request_pending &&
 317             dev->power.request > RPM_REQ_IDLE)
 318                 retval = -EAGAIN;
 319
 320         /* Act as though RPM_NOWAIT is always set. */
 321         else if (dev->power.idle_notification)
 322                 retval = -EINPROGRESS;
 323         if (retval)
 324                 goto out;
 325
 326         /* Pending requests need to be canceled. */
 327         dev->power.request = RPM_REQ_NONE;
 328
 329         if (dev->power.no_callbacks)
 330                 goto out;
 331
 332         /* Carry out an asynchronous or a synchronous idle notification. */
 333         if (rpmflags & RPM_ASYNC) {
 334                 dev->power.request = RPM_REQ_IDLE;
 335                 if (!dev->power.request_pending) {
 336                         dev->power.request_pending = true;
 337                         queue_work(pm_wq, &dev->power.work);
 338                 }
 339                 trace_rpm_return_int(dev, _THIS_IP_, 0);
 340                 return 0;
 341         }
 342
 343         dev->power.idle_notification = true;
 344
 345         callback = RPM_GET_CALLBACK(dev, runtime_idle);
 346
 347         if (callback)
 348                 retval = __rpm_callback(callback, dev);
 349
 350         dev->power.idle_notification = false;
 351         wake_up_all(&dev->power.wait_queue);
 352
 353  out:
 354         trace_rpm_return_int(dev, _THIS_IP_, retval);
 355         return retval ? retval : rpm_suspend(dev, rpmflags | RPM_AUTO);
 356 }
 357
 358 /**
 359  * rpm_callback - Run a given runtime PM callback for a given device.
 360  * @cb: Runtime PM callback to run.
 361  * @dev: Device to run the callback for.
 362  */
 363 static int rpm_callback(int (*cb)(struct device *), struct device *dev)
 364 {
 365         int retval;
 366
 367         if (!cb)
 368                 return -ENOSYS;
 369
 370         if (dev->power.memalloc_noio) {
 371                 unsigned int noio_flag;
 372
 373                 /*
 374                  * Deadlock might be caused if memory allocation with
 375                  * GFP_KERNEL happens inside runtime_suspend and
 376                  * runtime_resume callbacks of one block device's
 377                  * ancestor or the block device itself. Network
 378                  * device might be thought as part of iSCSI block
 379                  * device, so network device and its ancestor should
 380                  * be marked as memalloc_noio too.
 381                  */
 382                 noio_flag = memalloc_noio_save();
 383                 retval = __rpm_callback(cb, dev);
 384                 memalloc_noio_restore(noio_flag);
 385         } else {
 386                 retval = __rpm_callback(cb, dev);
 387         }
 388
 389         dev->power.runtime_error = retval;
 390         return retval != -EACCES ? retval : -EIO;
 391 }
 392
 393 /**
 394  * rpm_suspend - Carry out runtime suspend of given device.
 395  * @dev: Device to suspend.
 396  * @rpmflags: Flag bits.
 397  *
 398  * Check if the device's runtime PM status allows it to be suspended.
 399  * Cancel a pending idle notification, autosuspend or suspend. If
 400  * another suspend has been started earlier, either return immediately
 401  * or wait for it to finish, depending on the RPM_NOWAIT and RPM_ASYNC
 402  * flags. If the RPM_ASYNC flag is set then queue a suspend request;
 403  * otherwise run the ->runtime_suspend() callback directly. When
 404  * ->runtime_suspend succeeded, if a deferred resume was requested while
 405  * the callback was running then carry it out, otherwise send an idle
 406  * notification for its parent (if the suspend succeeded and both
 407  * ignore_children of parent->power and irq_safe of dev->power are not set).
 408  * If ->runtime_suspend failed with -EAGAIN or -EBUSY, and if the RPM_AUTO
 409  * flag is set and the next autosuspend-delay expiration time is in the
 410  * future, schedule another autosuspend attempt.
 411  *
 412  * This function must be called under dev->power.lock with interrupts disabled.
 413  */
 414 static int rpm_suspend(struct device *dev, int rpmflags)
 415         __releases(&dev->power.lock) __acquires(&dev->power.lock)
 416 {
 417         int (*callback)(struct device *);
 418         struct device *parent = NULL;
 419         int retval;
 420
 421         trace_rpm_suspend(dev, rpmflags);
 422
 423  repeat:
 424         retval = rpm_check_suspend_allowed(dev);
 425
 426         if (retval < 0)
 427                 ;       /* Conditions are wrong. */
 428
 429         /* Synchronous suspends are not allowed in the RPM_RESUMING state. */
 430         else if (dev->power.runtime_status == RPM_RESUMING &&
 431             !(rpmflags & RPM_ASYNC))
 432                 retval = -EAGAIN;
 433         if (retval)
 434                 goto out;
 435
 436         /* If the autosuspend_delay time hasn't expired yet, reschedule. */
 437         if ((rpmflags & RPM_AUTO)
 438             && dev->power.runtime_status != RPM_SUSPENDING) {
 439                 unsigned long expires = pm_runtime_autosuspend_expiration(dev);
 440
 441                 if (expires != 0) {
 442                         /* Pending requests need to be canceled. */
 443                         dev->power.request = RPM_REQ_NONE;
 444
 445                         /*
 446                          * Optimization: If the timer is already running and is
 447                          * set to expire at or before the autosuspend delay,
 448                          * avoid the overhead of resetting it.  Just let it
 449                          * expire; pm_suspend_timer_fn() will take care of the
 450                          * rest.
 451                          */
 452                         if (!(dev->power.timer_expires && time_before_eq(
 453                             dev->power.timer_expires, expires))) {
 454                                 dev->power.timer_expires = expires;
 455                                 mod_timer(&dev->power.suspend_timer, expires);
 456                         }
 457                         dev->power.timer_autosuspends = 1;
 458                         goto out;
 459                 }
 460         }
 461
 462         /* Other scheduled or pending requests need to be canceled. */
 463         pm_runtime_cancel_pending(dev);
 464
 465         if (dev->power.runtime_status == RPM_SUSPENDING) {
 466                 DEFINE_WAIT(wait);
 467
 468                 if (rpmflags & (RPM_ASYNC | RPM_NOWAIT)) {
 469                         retval = -EINPROGRESS;
 470                         goto out;
 471                 }
 472
 473                 if (dev->power.irq_safe) {
 474                         spin_unlock(&dev->power.lock);
 475
 476                         cpu_relax();
 477
 478                         spin_lock(&dev->power.lock);
 479                         goto repeat;
 480                 }
 481
 482                 /* Wait for the other suspend running in parallel with us. */
 483                 for (;;) {
 484                         prepare_to_wait(&dev->power.wait_queue, &wait,
 485                                         TASK_UNINTERRUPTIBLE);
 486                         if (dev->power.runtime_status != RPM_SUSPENDING)
 487                                 break;
 488
 489                         spin_unlock_irq(&dev->power.lock);
 490
 491                         schedule();
 492
 493                         spin_lock_irq(&dev->power.lock);
 494                 }
 495                 finish_wait(&dev->power.wait_queue, &wait);
 496                 goto repeat;
 497         }
 498
 499         if (dev->power.no_callbacks)
 500                 goto no_callback;       /* Assume success. */
 501
 502         /* Carry out an asynchronous or a synchronous suspend. */
 503         if (rpmflags & RPM_ASYNC) {
 504                 dev->power.request = (rpmflags & RPM_AUTO) ?
 505                     RPM_REQ_AUTOSUSPEND : RPM_REQ_SUSPEND;
 506                 if (!dev->power.request_pending) {
 507                         dev->power.request_pending = true;
 508                         queue_work(pm_wq, &dev->power.work);
 509                 }
 510                 goto out;
 511         }
 512
 513         __update_runtime_status(dev, RPM_SUSPENDING);
 514
 515         callback = RPM_GET_CALLBACK(dev, runtime_suspend);
 516
 517         retval = rpm_callback(callback, dev);
 518         if (retval)
 519                 goto fail;
 520
 521  no_callback:
 522         __update_runtime_status(dev, RPM_SUSPENDED);
 523         pm_runtime_deactivate_timer(dev);
 524
 525         if (dev->parent) {
 526                 parent = dev->parent;
 527                 atomic_add_unless(&parent->power.child_count, -1, 0);
 528         }
 529         wake_up_all(&dev->power.wait_queue);
 530
 531         if (dev->power.deferred_resume) {
 532                 dev->power.deferred_resume = false;
 533                 rpm_resume(dev, 0);
 534                 retval = -EAGAIN;
 535                 goto out;
 536         }
 537
 538         /* Maybe the parent is now able to suspend. */
 539         if (parent && !parent->power.ignore_children && !dev->power.irq_safe) {
 540                 spin_unlock(&dev->power.lock);
 541
 542                 spin_lock(&parent->power.lock);
 543                 rpm_idle(parent, RPM_ASYNC);
 544                 spin_unlock(&parent->power.lock);
 545
 546                 spin_lock(&dev->power.lock);
 547         }
 548
 549  out:
 550         trace_rpm_return_int(dev, _THIS_IP_, retval);
 551
 552         return retval;
 553
 554  fail:
 555         __update_runtime_status(dev, RPM_ACTIVE);
 556         dev->power.deferred_resume = false;
 557         wake_up_all(&dev->power.wait_queue);
 558
 559         if (retval == -EAGAIN || retval == -EBUSY) {
 560                 dev->power.runtime_error = 0;
 561
 562                 /*
 563                  * If the callback routine failed an autosuspend, and
 564                  * if the last_busy time has been updated so that there
 565                  * is a new autosuspend expiration time, automatically
 566                  * reschedule another autosuspend.
 567                  */
 568                 if ((rpmflags & RPM_AUTO) &&
 569                     pm_runtime_autosuspend_expiration(dev) != 0)
 570                         goto repeat;
 571         } else {
 572                 pm_runtime_cancel_pending(dev);
 573         }
 574         goto out;
 575 }
 576
 577 /**
 578  * rpm_resume - Carry out runtime resume of given device.
 579  * @dev: Device to resume.
 580  * @rpmflags: Flag bits.
 581  *
 582  * Check if the device's runtime PM status allows it to be resumed.  Cancel
 583  * any scheduled or pending requests.  If another resume has been started
 584  * earlier, either return immediately or wait for it to finish, depending on the
 585  * RPM_NOWAIT and RPM_ASYNC flags.  Similarly, if there's a suspend running in
 586  * parallel with this function, either tell the other process to resume after
 587  * suspending (deferred_resume) or wait for it to finish.  If the RPM_ASYNC
 588  * flag is set then queue a resume request; otherwise run the
 589  * ->runtime_resume() callback directly.  Queue an idle notification for the
 590  * device if the resume succeeded.
 591  *
 592  * This function must be called under dev->power.lock with interrupts disabled.
 593  */
 594 static int rpm_resume(struct device *dev, int rpmflags)
 595         __releases(&dev->power.lock) __acquires(&dev->power.lock)
 596 {
 597         int (*callback)(struct device *);
 598         struct device *parent = NULL;
 599         int retval = 0;
 600
 601         trace_rpm_resume(dev, rpmflags);
 602
 603  repeat:
 604         if (dev->power.runtime_error)
 605                 retval = -EINVAL;
 606         else if (dev->power.disable_depth == 1 && dev->power.is_suspended
 607             && dev->power.runtime_status == RPM_ACTIVE)
 608                 retval = 1;
 609         else if (dev->power.disable_depth > 0)
 610                 retval = -EACCES;
 611         if (retval)
 612                 goto out;
 613
 614         /*
 615          * Other scheduled or pending requests need to be canceled.  Small
 616          * optimization: If an autosuspend timer is running, leave it running
 617          * rather than cancelling it now only to restart it again in the near
 618          * future.
 619          */
 620         dev->power.request = RPM_REQ_NONE;
 621         if (!dev->power.timer_autosuspends)
 622                 pm_runtime_deactivate_timer(dev);
 623
 624         if (dev->power.runtime_status == RPM_ACTIVE) {
 625                 retval = 1;
 626                 goto out;
 627         }
 628
 629         if (dev->power.runtime_status == RPM_RESUMING
 630             || dev->power.runtime_status == RPM_SUSPENDING) {
 631                 DEFINE_WAIT(wait);
 632
 633                 if (rpmflags & (RPM_ASYNC | RPM_NOWAIT)) {
 634                         if (dev->power.runtime_status == RPM_SUSPENDING)
 635                                 dev->power.deferred_resume = true;
 636                         else
 637                                 retval = -EINPROGRESS;
 638                         goto out;
 639                 }
 640
 641                 if (dev->power.irq_safe) {
 642                         spin_unlock(&dev->power.lock);
 643
 644                         cpu_relax();
 645
 646                         spin_lock(&dev->power.lock);
 647                         goto repeat;
 648                 }
 649
 650                 /* Wait for the operation carried out in parallel with us. */
 651                 for (;;) {
 652                         prepare_to_wait(&dev->power.wait_queue, &wait,
 653                                         TASK_UNINTERRUPTIBLE);
 654                         if (dev->power.runtime_status != RPM_RESUMING
 655                             && dev->power.runtime_status != RPM_SUSPENDING)
 656                                 break;
 657
 658                         spin_unlock_irq(&dev->power.lock);
 659
 660                         schedule();
 661
 662                         spin_lock_irq(&dev->power.lock);
 663                 }
 664                 finish_wait(&dev->power.wait_queue, &wait);
 665                 goto repeat;
 666         }
 667
 668         /*
 669          * See if we can skip waking up the parent.  This is safe only if
 670          * power.no_callbacks is set, because otherwise we don't know whether
 671          * the resume will actually succeed.
 672          */
 673         if (dev->power.no_callbacks && !parent && dev->parent) {
 674                 spin_lock_nested(&dev->parent->power.lock, SINGLE_DEPTH_NESTING);
 675                 if (dev->parent->power.disable_depth > 0
 676                     || dev->parent->power.ignore_children
 677                     || dev->parent->power.runtime_status == RPM_ACTIVE) {
 678                         atomic_inc(&dev->parent->power.child_count);
 679                         spin_unlock(&dev->parent->power.lock);
 680                         retval = 1;
 681                         goto no_callback;       /* Assume success. */
 682                 }
 683                 spin_unlock(&dev->parent->power.lock);
 684         }
 685
 686         /* Carry out an asynchronous or a synchronous resume. */
 687         if (rpmflags & RPM_ASYNC) {
 688                 dev->power.request = RPM_REQ_RESUME;
 689                 if (!dev->power.request_pending) {
 690                         dev->power.request_pending = true;
 691                         queue_work(pm_wq, &dev->power.work);
 692                 }
 693                 retval = 0;
 694                 goto out;
 695         }
 696
 697         if (!parent && dev->parent) {
 698                 /*
 699                  * Increment the parent's usage counter and resume it if
 700                  * necessary.  Not needed if dev is irq-safe; then the
 701                  * parent is permanently resumed.
 702                  */
 703                 parent = dev->parent;
 704                 if (dev->power.irq_safe)
 705                         goto skip_parent;
 706                 spin_unlock(&dev->power.lock);
 707
 708                 pm_runtime_get_noresume(parent);
 709
 710                 spin_lock(&parent->power.lock);
 711                 /*
 712                  * We can resume if the parent's runtime PM is disabled or it
 713                  * is set to ignore children.
 714                  */
 715                 if (!parent->power.disable_depth
 716                     && !parent->power.ignore_children) {
 717                         rpm_resume(parent, 0);
 718                         if (parent->power.runtime_status != RPM_ACTIVE)
 719                                 retval = -EBUSY;
 720                 }
 721                 spin_unlock(&parent->power.lock);
 722
 723                 spin_lock(&dev->power.lock);
 724                 if (retval)
 725                         goto out;
 726                 goto repeat;
 727         }
 728  skip_parent:
 729
 730         if (dev->power.no_callbacks)
 731                 goto no_callback;       /* Assume success. */
 732
 733         __update_runtime_status(dev, RPM_RESUMING);
 734
 735         callback = RPM_GET_CALLBACK(dev, runtime_resume);
 736
 737         retval = rpm_callback(callback, dev);
 738         if (retval) {
 739                 __update_runtime_status(dev, RPM_SUSPENDED);
 740                 pm_runtime_cancel_pending(dev);
 741         } else {
 742  no_callback:
 743                 __update_runtime_status(dev, RPM_ACTIVE);
 744                 if (parent)
 745                         atomic_inc(&parent->power.child_count);
 746         }
 747         wake_up_all(&dev->power.wait_queue);
 748
 749         if (retval >= 0)
 750                 rpm_idle(dev, RPM_ASYNC);
 751
 752  out:
 753         if (parent && !dev->power.irq_safe) {
 754                 spin_unlock_irq(&dev->power.lock);
 755
 756                 pm_runtime_put(parent);
 757
 758                 spin_lock_irq(&dev->power.lock);
 759         }
 760
 761         trace_rpm_return_int(dev, _THIS_IP_, retval);
 762
 763         return retval;
 764 }
 765
 766 /**
 767  * pm_runtime_work - Universal runtime PM work function.
 768  * @work: Work structure used for scheduling the execution of this function.
 769  *
 770  * Use @work to get the device object the work is to be done for, determine what
 771  * is to be done and execute the appropriate runtime PM function.
 772  */
 773 static void pm_runtime_work(struct work_struct *work)
 774 {
 775         struct device *dev = container_of(work, struct device, power.work);
 776         enum rpm_request req;
 777
 778         spin_lock_irq(&dev->power.lock);
 779
 780         if (!dev->power.request_pending)
 781                 goto out;
 782
 783         req = dev->power.request;
 784         dev->power.request = RPM_REQ_NONE;
 785         dev->power.request_pending = false;
 786
 787         switch (req) {
 788         case RPM_REQ_NONE:
 789                 break;
 790         case RPM_REQ_IDLE:
 791                 rpm_idle(dev, RPM_NOWAIT);
 792                 break;
 793         case RPM_REQ_SUSPEND:
 794                 rpm_suspend(dev, RPM_NOWAIT);
 795                 break;
 796         case RPM_REQ_AUTOSUSPEND:
 797                 rpm_suspend(dev, RPM_NOWAIT | RPM_AUTO);
 798                 break;
 799         case RPM_REQ_RESUME:
 800                 rpm_resume(dev, RPM_NOWAIT);
 801                 break;
 802         }
 803
 804  out:
 805         spin_unlock_irq(&dev->power.lock);
 806 }
 807
 808 /**
 809  * pm_suspend_timer_fn - Timer function for pm_schedule_suspend().
 810  * @data: Device pointer passed by pm_schedule_suspend().
 811  *
 812  * Check if the time is right and queue a suspend request.
 813  */
 814 static void pm_suspend_timer_fn(unsigned long data)
 815 {
 816         struct device *dev = (struct device *)data;
 817         unsigned long flags;
 818         unsigned long expires;
 819
 820         spin_lock_irqsave(&dev->power.lock, flags);
 821
 822         expires = dev->power.timer_expires;
 823         /* If 'expire' is after 'jiffies' we've been called too early. */
 824         if (expires > 0 && !time_after(expires, jiffies)) {
 825                 dev->power.timer_expires = 0;
 826                 rpm_suspend(dev, dev->power.timer_autosuspends ?
 827                     (RPM_ASYNC | RPM_AUTO) : RPM_ASYNC);
 828         }
 829
 830         spin_unlock_irqrestore(&dev->power.lock, flags);
 831 }
 832
 833 /**
 834  * pm_schedule_suspend - Set up a timer to submit a suspend request in future.
 835  * @dev: Device to suspend.
 836  * @delay: Time to wait before submitting a suspend request, in milliseconds.
 837  */
 838 int pm_schedule_suspend(struct device *dev, unsigned int delay)
 839 {
 840         unsigned long flags;
 841         int retval;
 842
 843         spin_lock_irqsave(&dev->power.lock, flags);
 844
 845         if (!delay) {
 846                 retval = rpm_suspend(dev, RPM_ASYNC);
 847                 goto out;
 848         }
 849
 850         retval = rpm_check_suspend_allowed(dev);
 851         if (retval)
 852                 goto out;
 853
 854         /* Other scheduled or pending requests need to be canceled. */
 855         pm_runtime_cancel_pending(dev);
 856
 857         dev->power.timer_expires = jiffies + msecs_to_jiffies(delay);
 858         dev->power.timer_expires += !dev->power.timer_expires;
 859         dev->power.timer_autosuspends = 0;
 860         mod_timer(&dev->power.suspend_timer, dev->power.timer_expires);
 861
 862  out:
 863         spin_unlock_irqrestore(&dev->power.lock, flags);
 864
 865         return retval;
 866 }
 867 EXPORT_SYMBOL_GPL(pm_schedule_suspend);
 868
 869 /**
 870  * __pm_runtime_idle - Entry point for runtime idle operations.
 871  * @dev: Device to send idle notification for.
 872  * @rpmflags: Flag bits.
 873  *
 874  * If the RPM_GET_PUT flag is set, decrement the device's usage count and
 875  * return immediately if it is larger than zero.  Then carry out an idle
 876  * notification, either synchronous or asynchronous.
 877  *
 878  * This routine may be called in atomic context if the RPM_ASYNC flag is set,
 879  * or if pm_runtime_irq_safe() has been called.
 880  */
 881 int __pm_runtime_idle(struct device *dev, int rpmflags)
 882 {
 883         unsigned long flags;
 884         int retval;
 885
 886         might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe);
 887
 888         if (rpmflags & RPM_GET_PUT) {
 889                 if (!atomic_dec_and_test(&dev->power.usage_count))
 890                         return 0;
 891         }
 892
 893         spin_lock_irqsave(&dev->power.lock, flags);
 894         retval = rpm_idle(dev, rpmflags);
 895         spin_unlock_irqrestore(&dev->power.lock, flags);
 896
 897         return retval;
 898 }
 899 EXPORT_SYMBOL_GPL(__pm_runtime_idle);
 900
 901 /**
 902  * __pm_runtime_suspend - Entry point for runtime put/suspend operations.
 903  * @dev: Device to suspend.
 904  * @rpmflags: Flag bits.
 905  *
 906  * If the RPM_GET_PUT flag is set, decrement the device's usage count and
 907  * return immediately if it is larger than zero.  Then carry out a suspend,
 908  * either synchronous or asynchronous.
 909  *
 910  * This routine may be called in atomic context if the RPM_ASYNC flag is set,
 911  * or if pm_runtime_irq_safe() has been called.
 912  */
 913 int __pm_runtime_suspend(struct device *dev, int rpmflags)
 914 {
 915         unsigned long flags;
 916         int retval;
 917
 918         might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe);
 919
 920         if (rpmflags & RPM_GET_PUT) {
 921                 if (!atomic_dec_and_test(&dev->power.usage_count))
 922                         return 0;
 923         }
 924
 925         spin_lock_irqsave(&dev->power.lock, flags);
 926         retval = rpm_suspend(dev, rpmflags);
 927         spin_unlock_irqrestore(&dev->power.lock, flags);
 928
 929         return retval;
 930 }
 931 EXPORT_SYMBOL_GPL(__pm_runtime_suspend);
 932
 933 /**
 934  * __pm_runtime_resume - Entry point for runtime resume operations.
 935  * @dev: Device to resume.
 936  * @rpmflags: Flag bits.
 937  *
 938  * If the RPM_GET_PUT flag is set, increment the device's usage count.  Then
 939  * carry out a resume, either synchronous or asynchronous.
 940  *
 941  * This routine may be called in atomic context if the RPM_ASYNC flag is set,
 942  * or if pm_runtime_irq_safe() has been called.
 943  */
 944 int __pm_runtime_resume(struct device *dev, int rpmflags)
 945 {
 946         unsigned long flags;
 947         int retval;
 948
 949         might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe);
 950
 951         if (rpmflags & RPM_GET_PUT)
 952                 atomic_inc(&dev->power.usage_count);
 953
 954         spin_lock_irqsave(&dev->power.lock, flags);
 955         retval = rpm_resume(dev, rpmflags);
 956         spin_unlock_irqrestore(&dev->power.lock, flags);
 957
 958         return retval;
 959 }
 960 EXPORT_SYMBOL_GPL(__pm_runtime_resume);
 961
 962 /**
 963  * __pm_runtime_set_status - Set runtime PM status of a device.
 964  * @dev: Device to handle.
 965  * @status: New runtime PM status of the device.
 966  *
 967  * If runtime PM of the device is disabled or its power.runtime_error field is
 968  * different from zero, the status may be changed either to RPM_ACTIVE, or to
 969  * RPM_SUSPENDED, as long as that reflects the actual state of the device.
 970  * However, if the device has a parent and the parent is not active, and the
 971  * parent's power.ignore_children flag is unset, the device's status cannot be
 972  * set to RPM_ACTIVE, so -EBUSY is returned in that case.
 973  *
 974  * If successful, __pm_runtime_set_status() clears the power.runtime_error field
 975  * and the device parent's counter of unsuspended children is modified to
 976  * reflect the new status.  If the new status is RPM_SUSPENDED, an idle
 977  * notification request for the parent is submitted.
 978  */
 979 int __pm_runtime_set_status(struct device *dev, unsigned int status)
 980 {
 981         struct device *parent = dev->parent;
 982         unsigned long flags;
 983         bool notify_parent = false;
 984         int error = 0;
 985
 986         if (status != RPM_ACTIVE && status != RPM_SUSPENDED)
 987                 return -EINVAL;
 988
 989         spin_lock_irqsave(&dev->power.lock, flags);
 990
 991         if (!dev->power.runtime_error && !dev->power.disable_depth) {
 992                 error = -EAGAIN;
 993                 goto out;
 994         }
 995
 996         if (dev->power.runtime_status == status)
 997                 goto out_set;
 998
 999         if (status == RPM_SUSPENDED) {
1000                 /* It always is possible to set the status to 'suspended'. */
1001                 if (parent) {
1002                         atomic_add_unless(&parent->power.child_count, -1, 0);
1003                         notify_parent = !parent->power.ignore_children;
1004                 }
1005                 goto out_set;
1006         }
1007
1008         if (parent) {
1009                 spin_lock_nested(&parent->power.lock, SINGLE_DEPTH_NESTING);
1010
1011                 /*
1012                  * It is invalid to put an active child under a parent that is
1013                  * not active, has runtime PM enabled and the
1014                  * 'power.ignore_children' flag unset.
1015                  */
1016                 if (!parent->power.disable_depth
1017                     && !parent->power.ignore_children
1018                     && parent->power.runtime_status != RPM_ACTIVE)
1019                         error = -EBUSY;
1020                 else if (dev->power.runtime_status == RPM_SUSPENDED)
1021                         atomic_inc(&parent->power.child_count);
1022
1023                 spin_unlock(&parent->power.lock);
1024
1025                 if (error)
1026                         goto out;
1027         }
1028
1029  out_set:
1030         __update_runtime_status(dev, status);
1031         dev->power.runtime_error = 0;
1032  out:
1033         spin_unlock_irqrestore(&dev->power.lock, flags);
1034
1035         if (notify_parent)
1036                 pm_request_idle(parent);
1037
1038         return error;
1039 }
1040 EXPORT_SYMBOL_GPL(__pm_runtime_set_status);
1041
1042 /**
1043  * __pm_runtime_barrier - Cancel pending requests and wait for completions.
1044  * @dev: Device to handle.
1045  *
1046  * Flush all pending requests for the device from pm_wq and wait for all
1047  * runtime PM operations involving the device in progress to complete.
1048  *
1049  * Should be called under dev->power.lock with interrupts disabled.
1050  */
1051 static void __pm_runtime_barrier(struct device *dev)
1052 {
1053         pm_runtime_deactivate_timer(dev);
1054
1055         if (dev->power.request_pending) {
1056                 dev->power.request = RPM_REQ_NONE;
1057                 spin_unlock_irq(&dev->power.lock);
1058
1059                 cancel_work_sync(&dev->power.work);
1060
1061                 spin_lock_irq(&dev->power.lock);
1062                 dev->power.request_pending = false;
1063         }
1064
1065         if (dev->power.runtime_status == RPM_SUSPENDING
1066             || dev->power.runtime_status == RPM_RESUMING
1067             || dev->power.idle_notification) {
1068                 DEFINE_WAIT(wait);
1069
1070                 /* Suspend, wake-up or idle notification in progress. */
1071                 for (;;) {
1072                         prepare_to_wait(&dev->power.wait_queue, &wait,
1073                                         TASK_UNINTERRUPTIBLE);
1074                         if (dev->power.runtime_status != RPM_SUSPENDING
1075                             && dev->power.runtime_status != RPM_RESUMING
1076                             && !dev->power.idle_notification)
1077                                 break;
1078                         spin_unlock_irq(&dev->power.lock);
1079
1080                         schedule();
1081
1082                         spin_lock_irq(&dev->power.lock);
1083                 }
1084                 finish_wait(&dev->power.wait_queue, &wait);
1085         }
1086 }
1087
1088 /**
1089  * pm_runtime_barrier - Flush pending requests and wait for completions.
1090  * @dev: Device to handle.
1091  *
1092  * Prevent the device from being suspended by incrementing its usage counter and
1093  * if there's a pending resume request for the device, wake the device up.
1094  * Next, make sure that all pending requests for the device have been flushed
1095  * from pm_wq and wait for all runtime PM operations involving the device in
1096  * progress to complete.
1097  *
1098  * Return value:
1099  * 1, if there was a resume request pending and the device had to be woken up,
1100  * 0, otherwise
1101  */
1102 int pm_runtime_barrier(struct device *dev)
1103 {
1104         int retval = 0;
1105
1106         pm_runtime_get_noresume(dev);
1107         spin_lock_irq(&dev->power.lock);
1108
1109         if (dev->power.request_pending
1110             && dev->power.request == RPM_REQ_RESUME) {
1111                 rpm_resume(dev, 0);
1112                 retval = 1;
1113         }
1114
1115         __pm_runtime_barrier(dev);
1116
1117         spin_unlock_irq(&dev->power.lock);
1118         pm_runtime_put_noidle(dev);
1119
1120         return retval;
1121 }
1122 EXPORT_SYMBOL_GPL(pm_runtime_barrier);
1123
1124 /**
1125  * __pm_runtime_disable - Disable runtime PM of a device.
1126  * @dev: Device to handle.
1127  * @check_resume: If set, check if there's a resume request for the device.
1128  *
1129  * Increment power.disable_depth for the device and if it was zero previously,
1130  * cancel all pending runtime PM requests for the device and wait for all
1131  * operations in progress to complete.  The device can be either active or
1132  * suspended after its runtime PM has been disabled.
1133  *
1134  * If @check_resume is set and there's a resume request pending when
1135  * __pm_runtime_disable() is called and power.disable_depth is zero, the
1136  * function will wake up the device before disabling its runtime PM.
1137  */
1138 void __pm_runtime_disable(struct device *dev, bool check_resume)
1139 {
1140         spin_lock_irq(&dev->power.lock);
1141
1142         if (dev->power.disable_depth > 0) {
1143                 dev->power.disable_depth++;
1144                 goto out;
1145         }
1146
1147         /*
1148          * Wake up the device if there's a resume request pending, because that
1149          * means there probably is some I/O to process and disabling runtime PM
1150          * shouldn't prevent the device from processing the I/O.
1151          */
1152         if (check_resume && dev->power.request_pending
1153             && dev->power.request == RPM_REQ_RESUME) {
1154                 /*
1155                  * Prevent suspends and idle notifications from being carried
1156                  * out after we have woken up the device.
1157                  */
1158                 pm_runtime_get_noresume(dev);
1159
1160                 rpm_resume(dev, 0);
1161
1162                 pm_runtime_put_noidle(dev);
1163         }
1164
1165         if (!dev->power.disable_depth++)
1166                 __pm_runtime_barrier(dev);
1167
1168  out:
1169         spin_unlock_irq(&dev->power.lock);
1170 }
1171 EXPORT_SYMBOL_GPL(__pm_runtime_disable);
1172
1173 /**
1174  * pm_runtime_enable - Enable runtime PM of a device.
1175  * @dev: Device to handle.
1176  */
1177 void pm_runtime_enable(struct device *dev)
1178 {
1179         unsigned long flags;
1180
1181         spin_lock_irqsave(&dev->power.lock, flags);
1182
1183         if (dev->power.disable_depth > 0)
1184                 dev->power.disable_depth--;
1185         else
1186                 dev_warn(dev, "Unbalanced %s!\n", __func__);
1187
1188         spin_unlock_irqrestore(&dev->power.lock, flags);
1189 }
1190 EXPORT_SYMBOL_GPL(pm_runtime_enable);
1191
1192 /**
1193  * pm_runtime_forbid - Block runtime PM of a device.
1194  * @dev: Device to handle.
1195  *
1196  * Increase the device's usage count and clear its power.runtime_auto flag,
1197  * so that it cannot be suspended at run time until pm_runtime_allow() is called
1198  * for it.
1199  */
1200 void pm_runtime_forbid(struct device *dev)
1201 {
1202         spin_lock_irq(&dev->power.lock);
1203         if (!dev->power.runtime_auto)
1204                 goto out;
1205
1206         dev->power.runtime_auto = false;
1207         atomic_inc(&dev->power.usage_count);
1208         rpm_resume(dev, 0);
1209
1210  out:
1211         spin_unlock_irq(&dev->power.lock);
1212 }
1213 EXPORT_SYMBOL_GPL(pm_runtime_forbid);
1214
1215 /**
1216  * pm_runtime_allow - Unblock runtime PM of a device.
1217  * @dev: Device to handle.
1218  *
1219  * Decrease the device's usage count and set its power.runtime_auto flag.
1220  */
1221 void pm_runtime_allow(struct device *dev)
1222 {
1223         spin_lock_irq(&dev->power.lock);
1224         if (dev->power.runtime_auto)
1225                 goto out;
1226
1227         dev->power.runtime_auto = true;
1228         if (atomic_dec_and_test(&dev->power.usage_count))
1229                 rpm_idle(dev, RPM_AUTO);
1230
1231  out:
1232         spin_unlock_irq(&dev->power.lock);
1233 }
1234 EXPORT_SYMBOL_GPL(pm_runtime_allow);
1235
1236 /**
1237  * pm_runtime_no_callbacks - Ignore runtime PM callbacks for a device.
1238  * @dev: Device to handle.
1239  *
1240  * Set the power.no_callbacks flag, which tells the PM core that this
1241  * device is power-managed through its parent and has no runtime PM
1242  * callbacks of its own.  The runtime sysfs attributes will be removed.
1243  */
1244 void pm_runtime_no_callbacks(struct device *dev)
1245 {
1246         spin_lock_irq(&dev->power.lock);
1247         dev->power.no_callbacks = 1;
1248         spin_unlock_irq(&dev->power.lock);
1249         if (device_is_registered(dev))
1250                 rpm_sysfs_remove(dev);
1251 }
1252 EXPORT_SYMBOL_GPL(pm_runtime_no_callbacks);
1253
1254 /**
1255  * pm_runtime_irq_safe - Leave interrupts disabled during callbacks.
1256  * @dev: Device to handle
1257  *
1258  * Set the power.irq_safe flag, which tells the PM core that the
1259  * ->runtime_suspend() and ->runtime_resume() callbacks for this device should
1260  * always be invoked with the spinlock held and interrupts disabled.  It also
1261  * causes the parent's usage counter to be permanently incremented, preventing
1262  * the parent from runtime suspending -- otherwise an irq-safe child might have
1263  * to wait for a non-irq-safe parent.
1264  */
1265 void pm_runtime_irq_safe(struct device *dev)
1266 {
1267         if (dev->parent)
1268                 pm_runtime_get_sync(dev->parent);
1269         spin_lock_irq(&dev->power.lock);
1270         dev->power.irq_safe = 1;
1271         spin_unlock_irq(&dev->power.lock);
1272 }
1273 EXPORT_SYMBOL_GPL(pm_runtime_irq_safe);
1274
1275 /**
1276  * update_autosuspend - Handle a change to a device's autosuspend settings.
1277  * @dev: Device to handle.
1278  * @old_delay: The former autosuspend_delay value.
1279  * @old_use: The former use_autosuspend value.
1280  *
1281  * Prevent runtime suspend if the new delay is negative and use_autosuspend is
1282  * set; otherwise allow it.  Send an idle notification if suspends are allowed.
1283  *
1284  * This function must be called under dev->power.lock with interrupts disabled.
1285  */
1286 static void update_autosuspend(struct device *dev, int old_delay, int old_use)
1287 {
1288         int delay = dev->power.autosuspend_delay;
1289
1290         /* Should runtime suspend be prevented now? */
1291         if (dev->power.use_autosuspend && delay < 0) {
1292
1293                 /* If it used to be allowed then prevent it. */
1294                 if (!old_use || old_delay >= 0) {
1295                         atomic_inc(&dev->power.usage_count);
1296                         rpm_resume(dev, 0);
1297                 }
1298         }
1299
1300         /* Runtime suspend should be allowed now. */
1301         else {
1302
1303                 /* If it used to be prevented then allow it. */
1304                 if (old_use && old_delay < 0)
1305                         atomic_dec(&dev->power.usage_count);
1306
1307                 /* Maybe we can autosuspend now. */
1308                 rpm_idle(dev, RPM_AUTO);
1309         }
1310 }
1311
1312 /**
1313  * pm_runtime_set_autosuspend_delay - Set a device's autosuspend_delay value.
1314  * @dev: Device to handle.
1315  * @delay: Value of the new delay in milliseconds.
1316  *
1317  * Set the device's power.autosuspend_delay value.  If it changes to negative
1318  * and the power.use_autosuspend flag is set, prevent runtime suspends.  If it
1319  * changes the other way, allow runtime suspends.
1320  */
1321 void pm_runtime_set_autosuspend_delay(struct device *dev, int delay)
1322 {
1323         int old_delay, old_use;
1324
1325         spin_lock_irq(&dev->power.lock);
1326         old_delay = dev->power.autosuspend_delay;
1327         old_use = dev->power.use_autosuspend;
1328         dev->power.autosuspend_delay = delay;
1329         update_autosuspend(dev, old_delay, old_use);
1330         spin_unlock_irq(&dev->power.lock);
1331 }
1332 EXPORT_SYMBOL_GPL(pm_runtime_set_autosuspend_delay);
1333
1334 /**
1335  * __pm_runtime_use_autosuspend - Set a device's use_autosuspend flag.
1336  * @dev: Device to handle.
1337  * @use: New value for use_autosuspend.
1338  *
1339  * Set the device's power.use_autosuspend flag, and allow or prevent runtime
1340  * suspends as needed.
1341  */
1342 void __pm_runtime_use_autosuspend(struct device *dev, bool use)
1343 {
1344         int old_delay, old_use;
1345
1346         spin_lock_irq(&dev->power.lock);
1347         old_delay = dev->power.autosuspend_delay;
1348         old_use = dev->power.use_autosuspend;
1349         dev->power.use_autosuspend = use;
1350         update_autosuspend(dev, old_delay, old_use);
1351         spin_unlock_irq(&dev->power.lock);
1352 }
1353 EXPORT_SYMBOL_GPL(__pm_runtime_use_autosuspend);
1354
1355 /**
1356  * pm_runtime_init - Initialize runtime PM fields in given device object.
1357  * @dev: Device object to initialize.
1358  */
1359 void pm_runtime_init(struct device *dev)
1360 {
1361         dev->power.runtime_status = RPM_SUSPENDED;
1362         dev->power.idle_notification = false;
1363
1364         dev->power.disable_depth = 1;
1365         atomic_set(&dev->power.usage_count, 0);
1366
1367         dev->power.runtime_error = 0;
1368
1369         atomic_set(&dev->power.child_count, 0);
1370         pm_suspend_ignore_children(dev, false);
1371         dev->power.runtime_auto = true;
1372
1373         dev->power.request_pending = false;
1374         dev->power.request = RPM_REQ_NONE;
1375         dev->power.deferred_resume = false;
1376         dev->power.accounting_timestamp = jiffies;
1377         INIT_WORK(&dev->power.work, pm_runtime_work);
1378
1379         dev->power.timer_expires = 0;
1380         setup_timer(&dev->power.suspend_timer, pm_suspend_timer_fn,
1381                         (unsigned long)dev);
1382
1383         init_waitqueue_head(&dev->power.wait_queue);
1384 }
1385
1386 /**
1387  * pm_runtime_remove - Prepare for removing a device from device hierarchy.
1388  * @dev: Device object being removed from device hierarchy.
1389  */
1390 void pm_runtime_remove(struct device *dev)
1391 {
1392         __pm_runtime_disable(dev, false);
1393
1394         /* Change the status back to 'suspended' to match the initial status. */
1395         if (dev->power.runtime_status == RPM_ACTIVE)
1396                 pm_runtime_set_suspended(dev);
1397         if (dev->power.irq_safe && dev->parent)
1398                 pm_runtime_put(dev->parent);
1399 }
1400
1401 /**
1402  * pm_runtime_force_suspend - Force a device into suspend state if needed.
1403  * @dev: Device to suspend.
1404  *
1405  * Disable runtime PM so we safely can check the device's runtime PM status and
1406  * if it is active, invoke it's .runtime_suspend callback to bring it into
1407  * suspend state. Keep runtime PM disabled to preserve the state unless we
1408  * encounter errors.
1409  *
1410  * Typically this function may be invoked from a system suspend callback to make
1411  * sure the device is put into low power state.
1412  */
1413 int pm_runtime_force_suspend(struct device *dev)
1414 {
1415         int (*callback)(struct device *);
1416         int ret = 0;
1417
1418         pm_runtime_disable(dev);
1419         if (pm_runtime_status_suspended(dev))
1420                 return 0;
1421
1422         callback = RPM_GET_CALLBACK(dev, runtime_suspend);
1423
1424         if (!callback) {
1425                 ret = -ENOSYS;
1426                 goto err;
1427         }
1428
1429         ret = callback(dev);
1430         if (ret)
1431                 goto err;
1432
1433         pm_runtime_set_suspended(dev);
1434         return 0;
1435 err:
1436         pm_runtime_enable(dev);
1437         return ret;
1438 }
1439 EXPORT_SYMBOL_GPL(pm_runtime_force_suspend);
1440
1441 /**
1442  * pm_runtime_force_resume - Force a device into resume state.
1443  * @dev: Device to resume.
1444  *
1445  * Prior invoking this function we expect the user to have brought the device
1446  * into low power state by a call to pm_runtime_force_suspend(). Here we reverse
1447  * those actions and brings the device into full power. We update the runtime PM
1448  * status and re-enables runtime PM.
1449  *
1450  * Typically this function may be invoked from a system resume callback to make
1451  * sure the device is put into full power state.
1452  */
1453 int pm_runtime_force_resume(struct device *dev)
1454 {
1455         int (*callback)(struct device *);
1456         int ret = 0;
1457
1458         callback = RPM_GET_CALLBACK(dev, runtime_resume);
1459
1460         if (!callback) {
1461                 ret = -ENOSYS;
1462                 goto out;
1463         }
1464
1465         ret = callback(dev);
1466         if (ret)
1467                 goto out;
1468
1469         pm_runtime_set_active(dev);
1470         pm_runtime_mark_last_busy(dev);
1471 out:
1472         pm_runtime_enable(dev);
1473         return ret;
1474 }
1475 EXPORT_SYMBOL_GPL(pm_runtime_force_resume);