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 #ifdef CONFIG_PM_RUNTIME
  49
  50 static int rpm_resume(struct device *dev, int rpmflags);
  51 static int rpm_suspend(struct device *dev, int rpmflags);
  52
  53 /**
  54  * update_pm_runtime_accounting - Update the time accounting of power states
  55  * @dev: Device to update the accounting for
  56  *
  57  * In order to be able to have time accounting of the various power states
  58  * (as used by programs such as PowerTOP to show the effectiveness of runtime
  59  * PM), we need to track the time spent in each state.
  60  * update_pm_runtime_accounting must be called each time before the
  61  * runtime_status field is updated, to account the time in the old state
  62  * correctly.
  63  */
  64 void update_pm_runtime_accounting(struct device *dev)
  65 {
  66         unsigned long now = jiffies;
  67         unsigned long delta;
  68
  69         delta = now - dev->power.accounting_timestamp;
  70
  71         dev->power.accounting_timestamp = now;
  72
  73         if (dev->power.disable_depth > 0)
  74                 return;
  75
  76         if (dev->power.runtime_status == RPM_SUSPENDED)
  77                 dev->power.suspended_jiffies += delta;
  78         else
  79                 dev->power.active_jiffies += delta;
  80 }
  81
  82 static void __update_runtime_status(struct device *dev, enum rpm_status status)
  83 {
  84         update_pm_runtime_accounting(dev);
  85         dev->power.runtime_status = status;
  86 }
  87
  88 /**
  89  * pm_runtime_deactivate_timer - Deactivate given device's suspend timer.
  90  * @dev: Device to handle.
  91  */
  92 static void pm_runtime_deactivate_timer(struct device *dev)
  93 {
  94         if (dev->power.timer_expires > 0) {
  95                 del_timer(&dev->power.suspend_timer);
  96                 dev->power.timer_expires = 0;
  97         }
  98 }
  99
 100 /**
 101  * pm_runtime_cancel_pending - Deactivate suspend timer and cancel requests.
 102  * @dev: Device to handle.
 103  */
 104 static void pm_runtime_cancel_pending(struct device *dev)
 105 {
 106         pm_runtime_deactivate_timer(dev);
 107         /*
 108          * In case there's a request pending, make sure its work function will
 109          * return without doing anything.
 110          */
 111         dev->power.request = RPM_REQ_NONE;
 112 }
 113
 114 /*
 115  * pm_runtime_autosuspend_expiration - Get a device's autosuspend-delay expiration time.
 116  * @dev: Device to handle.
 117  *
 118  * Compute the autosuspend-delay expiration time based on the device's
 119  * power.last_busy time.  If the delay has already expired or is disabled
 120  * (negative) or the power.use_autosuspend flag isn't set, return 0.
 121  * Otherwise return the expiration time in jiffies (adjusted to be nonzero).
 122  *
 123  * This function may be called either with or without dev->power.lock held.
 124  * Either way it can be racy, since power.last_busy may be updated at any time.
 125  */
 126 unsigned long pm_runtime_autosuspend_expiration(struct device *dev)
 127 {
 128         int autosuspend_delay;
 129         long elapsed;
 130         unsigned long last_busy;
 131         unsigned long expires = 0;
 132
 133         if (!dev->power.use_autosuspend)
 134                 goto out;
 135
 136         autosuspend_delay = ACCESS_ONCE(dev->power.autosuspend_delay);
 137         if (autosuspend_delay < 0)
 138                 goto out;
 139
 140         last_busy = ACCESS_ONCE(dev->power.last_busy);
 141         elapsed = jiffies - last_busy;
 142         if (elapsed < 0)
 143                 goto out;       /* jiffies has wrapped around. */
 144
 145         /*
 146          * If the autosuspend_delay is >= 1 second, align the timer by rounding
 147          * up to the nearest second.
 148          */
 149         expires = last_busy + msecs_to_jiffies(autosuspend_delay);
 150         if (autosuspend_delay >= 1000)
 151                 expires = round_jiffies(expires);
 152         expires += !expires;
 153         if (elapsed >= expires - last_busy)
 154                 expires = 0;    /* Already expired. */
 155
 156  out:
 157         return expires;
 158 }
 159 EXPORT_SYMBOL_GPL(pm_runtime_autosuspend_expiration);
 160
 161 static int dev_memalloc_noio(struct device *dev, void *data)
 162 {
 163         return dev->power.memalloc_noio;
 164 }
 165
 166 /*
 167  * pm_runtime_set_memalloc_noio - Set a device's memalloc_noio flag.
 168  * @dev: Device to handle.
 169  * @enable: True for setting the flag and False for clearing the flag.
 170  *
 171  * Set the flag for all devices in the path from the device to the
 172  * root device in the device tree if @enable is true, otherwise clear
 173  * the flag for devices in the path whose siblings don't set the flag.
 174  *
 175  * The function should only be called by block device, or network
 176  * device driver for solving the deadlock problem during runtime
 177  * resume/suspend:
 178  *
 179  *     If memory allocation with GFP_KERNEL is called inside runtime
 180  *     resume/suspend callback of any one of its ancestors(or the
 181  *     block device itself), the deadlock may be triggered inside the
 182  *     memory allocation since it might not complete until the block
 183  *     device becomes active and the involed page I/O finishes. The
 184  *     situation is pointed out first by Alan Stern. Network device
 185  *     are involved in iSCSI kind of situation.
 186  *
 187  * The lock of dev_hotplug_mutex is held in the function for handling
 188  * hotplug race because pm_runtime_set_memalloc_noio() may be called
 189  * in async probe().
 190  *
 191  * The function should be called between device_add() and device_del()
 192  * on the affected device(block/network device).
 193  */
 194 void pm_runtime_set_memalloc_noio(struct device *dev, bool enable)
 195 {
 196         static DEFINE_MUTEX(dev_hotplug_mutex);
 197
 198         mutex_lock(&dev_hotplug_mutex);
 199         for (;;) {
 200                 bool enabled;
 201
 202                 /* hold power lock since bitfield is not SMP-safe. */
 203                 spin_lock_irq(&dev->power.lock);
 204                 enabled = dev->power.memalloc_noio;
 205                 dev->power.memalloc_noio = enable;
 206                 spin_unlock_irq(&dev->power.lock);
 207
 208                 /*
 209                  * not need to enable ancestors any more if the device
 210                  * has been enabled.
 211                  */
 212                 if (enabled && enable)
 213                         break;
 214
 215                 dev = dev->parent;
 216
 217                 /*
 218                  * clear flag of the parent device only if all the
 219                  * children don't set the flag because ancestor's
 220                  * flag was set by any one of the descendants.
 221                  */
 222                 if (!dev || (!enable &&
 223                              device_for_each_child(dev, NULL,
 224                                                    dev_memalloc_noio)))
 225                         break;
 226         }
 227         mutex_unlock(&dev_hotplug_mutex);
 228 }
 229 EXPORT_SYMBOL_GPL(pm_runtime_set_memalloc_noio);
 230
 231 /**
 232  * rpm_check_suspend_allowed - Test whether a device may be suspended.
 233  * @dev: Device to test.
 234  */
 235 static int rpm_check_suspend_allowed(struct device *dev)
 236 {
 237         int retval = 0;
 238
 239         if (dev->power.runtime_error)
 240                 retval = -EINVAL;
 241         else if (dev->power.disable_depth > 0)
 242                 retval = -EACCES;
 243         else if (atomic_read(&dev->power.usage_count) > 0)
 244                 retval = -EAGAIN;
 245         else if (!pm_children_suspended(dev))
 246                 retval = -EBUSY;
 247
 248         /* Pending resume requests take precedence over suspends. */
 249         else if ((dev->power.deferred_resume
 250                         && dev->power.runtime_status == RPM_SUSPENDING)
 251             || (dev->power.request_pending
 252                         && dev->power.request == RPM_REQ_RESUME))
 253                 retval = -EAGAIN;
 254         else if (__dev_pm_qos_read_value(dev) < 0)
 255                 retval = -EPERM;
 256         else if (dev->power.runtime_status == RPM_SUSPENDED)
 257                 retval = 1;
 258
 259         return retval;
 260 }
 261
 262 /**
 263  * __rpm_callback - Run a given runtime PM callback for a given device.
 264  * @cb: Runtime PM callback to run.
 265  * @dev: Device to run the callback for.
 266  */
 267 static int __rpm_callback(int (*cb)(struct device *), struct device *dev)
 268         __releases(&dev->power.lock) __acquires(&dev->power.lock)
 269 {
 270         int retval;
 271
 272         if (dev->power.irq_safe)
 273                 spin_unlock(&dev->power.lock);
 274         else
 275                 spin_unlock_irq(&dev->power.lock);
 276
 277         retval = cb(dev);
 278
 279         if (dev->power.irq_safe)
 280                 spin_lock(&dev->power.lock);
 281         else
 282                 spin_lock_irq(&dev->power.lock);
 283
 284         return retval;
 285 }
 286
 287 /**
 288  * rpm_idle - Notify device bus type if the device can be suspended.
 289  * @dev: Device to notify the bus type about.
 290  * @rpmflags: Flag bits.
 291  *
 292  * Check if the device's runtime PM status allows it to be suspended.  If
 293  * another idle notification has been started earlier, return immediately.  If
 294  * the RPM_ASYNC flag is set then queue an idle-notification request; otherwise
 295  * run the ->runtime_idle() callback directly. If the ->runtime_idle callback
 296  * doesn't exist or if it returns 0, call rpm_suspend with the RPM_AUTO flag.
 297  *
 298  * This function must be called under dev->power.lock with interrupts disabled.
 299  */
 300 static int rpm_idle(struct device *dev, int rpmflags)
 301 {
 302         int (*callback)(struct device *);
 303         int retval;
 304
 305         trace_rpm_idle(dev, rpmflags);
 306         retval = rpm_check_suspend_allowed(dev);
 307         if (retval < 0)
 308                 ;       /* Conditions are wrong. */
 309
 310         /* Idle notifications are allowed only in the RPM_ACTIVE state. */
 311         else if (dev->power.runtime_status != RPM_ACTIVE)
 312                 retval = -EAGAIN;
 313
 314         /*
 315          * Any pending request other than an idle notification takes
 316          * precedence over us, except that the timer may be running.
 317          */
 318         else if (dev->power.request_pending &&
 319             dev->power.request > RPM_REQ_IDLE)
 320                 retval = -EAGAIN;
 321
 322         /* Act as though RPM_NOWAIT is always set. */
 323         else if (dev->power.idle_notification)
 324                 retval = -EINPROGRESS;
 325         if (retval)
 326                 goto out;
 327
 328         /* Pending requests need to be canceled. */
 329         dev->power.request = RPM_REQ_NONE;
 330
 331         if (dev->power.no_callbacks)
 332                 goto out;
 333
 334         /* Carry out an asynchronous or a synchronous idle notification. */
 335         if (rpmflags & RPM_ASYNC) {
 336                 dev->power.request = RPM_REQ_IDLE;
 337                 if (!dev->power.request_pending) {
 338                         dev->power.request_pending = true;
 339                         queue_work(pm_wq, &dev->power.work);
 340                 }
 341                 trace_rpm_return_int(dev, _THIS_IP_, 0);
 342                 return 0;
 343         }
 344
 345         dev->power.idle_notification = true;
 346
 347         callback = RPM_GET_CALLBACK(dev, runtime_idle);
 348
 349         if (callback)
 350                 retval = __rpm_callback(callback, dev);
 351
 352         dev->power.idle_notification = false;
 353         wake_up_all(&dev->power.wait_queue);
 354
 355  out:
 356         trace_rpm_return_int(dev, _THIS_IP_, retval);
 357         return retval ? retval : rpm_suspend(dev, rpmflags | RPM_AUTO);
 358 }
 359
 360 /**
 361  * rpm_callback - Run a given runtime PM callback for a given device.
 362  * @cb: Runtime PM callback to run.
 363  * @dev: Device to run the callback for.
 364  */
 365 static int rpm_callback(int (*cb)(struct device *), struct device *dev)
 366 {
 367         int retval;
 368
 369         if (!cb)
 370                 return -ENOSYS;
 371
 372         if (dev->power.memalloc_noio) {
 373                 unsigned int noio_flag;
 374
 375                 /*
 376                  * Deadlock might be caused if memory allocation with
 377                  * GFP_KERNEL happens inside runtime_suspend and
 378                  * runtime_resume callbacks of one block device's
 379                  * ancestor or the block device itself. Network
 380                  * device might be thought as part of iSCSI block
 381                  * device, so network device and its ancestor should
 382                  * be marked as memalloc_noio too.
 383                  */
 384                 noio_flag = memalloc_noio_save();
 385                 retval = __rpm_callback(cb, dev);
 386                 memalloc_noio_restore(noio_flag);
 387         } else {
 388                 retval = __rpm_callback(cb, dev);
 389         }
 390
 391         dev->power.runtime_error = retval;
 392         return retval != -EACCES ? retval : -EIO;
 393 }
 394
 395 /**
 396  * rpm_suspend - Carry out runtime suspend of given device.
 397  * @dev: Device to suspend.
 398  * @rpmflags: Flag bits.
 399  *
 400  * Check if the device's runtime PM status allows it to be suspended.
 401  * Cancel a pending idle notification, autosuspend or suspend. If
 402  * another suspend has been started earlier, either return immediately
 403  * or wait for it to finish, depending on the RPM_NOWAIT and RPM_ASYNC
 404  * flags. If the RPM_ASYNC flag is set then queue a suspend request;
 405  * otherwise run the ->runtime_suspend() callback directly. When
 406  * ->runtime_suspend succeeded, if a deferred resume was requested while
 407  * the callback was running then carry it out, otherwise send an idle
 408  * notification for its parent (if the suspend succeeded and both
 409  * ignore_children of parent->power and irq_safe of dev->power are not set).
 410  * If ->runtime_suspend failed with -EAGAIN or -EBUSY, and if the RPM_AUTO
 411  * flag is set and the next autosuspend-delay expiration time is in the
 412  * future, schedule another autosuspend attempt.
 413  *
 414  * This function must be called under dev->power.lock with interrupts disabled.
 415  */
 416 static int rpm_suspend(struct device *dev, int rpmflags)
 417         __releases(&dev->power.lock) __acquires(&dev->power.lock)
 418 {
 419         int (*callback)(struct device *);
 420         struct device *parent = NULL;
 421         int retval;
 422
 423         trace_rpm_suspend(dev, rpmflags);
 424
 425  repeat:
 426         retval = rpm_check_suspend_allowed(dev);
 427
 428         if (retval < 0)
 429                 ;       /* Conditions are wrong. */
 430
 431         /* Synchronous suspends are not allowed in the RPM_RESUMING state. */
 432         else if (dev->power.runtime_status == RPM_RESUMING &&
 433             !(rpmflags & RPM_ASYNC))
 434                 retval = -EAGAIN;
 435         if (retval)
 436                 goto out;
 437
 438         /* If the autosuspend_delay time hasn't expired yet, reschedule. */
 439         if ((rpmflags & RPM_AUTO)
 440             && dev->power.runtime_status != RPM_SUSPENDING) {
 441                 unsigned long expires = pm_runtime_autosuspend_expiration(dev);
 442
 443                 if (expires != 0) {
 444                         /* Pending requests need to be canceled. */
 445                         dev->power.request = RPM_REQ_NONE;
 446
 447                         /*
 448                          * Optimization: If the timer is already running and is
 449                          * set to expire at or before the autosuspend delay,
 450                          * avoid the overhead of resetting it.  Just let it
 451                          * expire; pm_suspend_timer_fn() will take care of the
 452                          * rest.
 453                          */
 454                         if (!(dev->power.timer_expires && time_before_eq(
 455                             dev->power.timer_expires, expires))) {
 456                                 dev->power.timer_expires = expires;
 457                                 mod_timer(&dev->power.suspend_timer, expires);
 458                         }
 459                         dev->power.timer_autosuspends = 1;
 460                         goto out;
 461                 }
 462         }
 463
 464         /* Other scheduled or pending requests need to be canceled. */
 465         pm_runtime_cancel_pending(dev);
 466
 467         if (dev->power.runtime_status == RPM_SUSPENDING) {
 468                 DEFINE_WAIT(wait);
 469
 470                 if (rpmflags & (RPM_ASYNC | RPM_NOWAIT)) {
 471                         retval = -EINPROGRESS;
 472                         goto out;
 473                 }
 474
 475                 if (dev->power.irq_safe) {
 476                         spin_unlock(&dev->power.lock);
 477
 478                         cpu_relax();
 479
 480                         spin_lock(&dev->power.lock);
 481                         goto repeat;
 482                 }
 483
 484                 /* Wait for the other suspend running in parallel with us. */
 485                 for (;;) {
 486                         prepare_to_wait(&dev->power.wait_queue, &wait,
 487                                         TASK_UNINTERRUPTIBLE);
 488                         if (dev->power.runtime_status != RPM_SUSPENDING)
 489                                 break;
 490
 491                         spin_unlock_irq(&dev->power.lock);
 492
 493                         schedule();
 494
 495                         spin_lock_irq(&dev->power.lock);
 496                 }
 497                 finish_wait(&dev->power.wait_queue, &wait);
 498                 goto repeat;
 499         }
 500
 501         if (dev->power.no_callbacks)
 502                 goto no_callback;       /* Assume success. */
 503
 504         /* Carry out an asynchronous or a synchronous suspend. */
 505         if (rpmflags & RPM_ASYNC) {
 506                 dev->power.request = (rpmflags & RPM_AUTO) ?
 507                     RPM_REQ_AUTOSUSPEND : RPM_REQ_SUSPEND;
 508                 if (!dev->power.request_pending) {
 509                         dev->power.request_pending = true;
 510                         queue_work(pm_wq, &dev->power.work);
 511                 }
 512                 goto out;
 513         }
 514
 515         __update_runtime_status(dev, RPM_SUSPENDING);
 516
 517         callback = RPM_GET_CALLBACK(dev, runtime_suspend);
 518
 519         retval = rpm_callback(callback, dev);
 520         if (retval)
 521                 goto fail;
 522
 523  no_callback:
 524         __update_runtime_status(dev, RPM_SUSPENDED);
 525         pm_runtime_deactivate_timer(dev);
 526
 527         if (dev->parent) {
 528                 parent = dev->parent;
 529                 atomic_add_unless(&parent->power.child_count, -1, 0);
 530         }
 531         wake_up_all(&dev->power.wait_queue);
 532
 533         if (dev->power.deferred_resume) {
 534                 dev->power.deferred_resume = false;
 535                 rpm_resume(dev, 0);
 536                 retval = -EAGAIN;
 537                 goto out;
 538         }
 539
 540         /* Maybe the parent is now able to suspend. */
 541         if (parent && !parent->power.ignore_children && !dev->power.irq_safe) {
 542                 spin_unlock(&dev->power.lock);
 543
 544                 spin_lock(&parent->power.lock);
 545                 rpm_idle(parent, RPM_ASYNC);
 546                 spin_unlock(&parent->power.lock);
 547
 548                 spin_lock(&dev->power.lock);
 549         }
 550
 551  out:
 552         trace_rpm_return_int(dev, _THIS_IP_, retval);
 553
 554         return retval;
 555
 556  fail:
 557         __update_runtime_status(dev, RPM_ACTIVE);
 558         dev->power.deferred_resume = false;
 559         wake_up_all(&dev->power.wait_queue);
 560
 561         if (retval == -EAGAIN || retval == -EBUSY) {
 562                 dev->power.runtime_error = 0;
 563
 564                 /*
 565                  * If the callback routine failed an autosuspend, and
 566                  * if the last_busy time has been updated so that there
 567                  * is a new autosuspend expiration time, automatically
 568                  * reschedule another autosuspend.
 569                  */
 570                 if ((rpmflags & RPM_AUTO) &&
 571                     pm_runtime_autosuspend_expiration(dev) != 0)
 572                         goto repeat;
 573         } else {
 574                 pm_runtime_cancel_pending(dev);
 575         }
 576         goto out;
 577 }
 578
 579 /**
 580  * rpm_resume - Carry out runtime resume of given device.
 581  * @dev: Device to resume.
 582  * @rpmflags: Flag bits.
 583  *
 584  * Check if the device's runtime PM status allows it to be resumed.  Cancel
 585  * any scheduled or pending requests.  If another resume has been started
 586  * earlier, either return immediately or wait for it to finish, depending on the
 587  * RPM_NOWAIT and RPM_ASYNC flags.  Similarly, if there's a suspend running in
 588  * parallel with this function, either tell the other process to resume after
 589  * suspending (deferred_resume) or wait for it to finish.  If the RPM_ASYNC
 590  * flag is set then queue a resume request; otherwise run the
 591  * ->runtime_resume() callback directly.  Queue an idle notification for the
 592  * device if the resume succeeded.
 593  *
 594  * This function must be called under dev->power.lock with interrupts disabled.
 595  */
 596 static int rpm_resume(struct device *dev, int rpmflags)
 597         __releases(&dev->power.lock) __acquires(&dev->power.lock)
 598 {
 599         int (*callback)(struct device *);
 600         struct device *parent = NULL;
 601         int retval = 0;
 602
 603         trace_rpm_resume(dev, rpmflags);
 604
 605  repeat:
 606         if (dev->power.runtime_error)
 607                 retval = -EINVAL;
 608         else if (dev->power.disable_depth == 1 && dev->power.is_suspended
 609             && dev->power.runtime_status == RPM_ACTIVE)
 610                 retval = 1;
 611         else if (dev->power.disable_depth > 0)
 612                 retval = -EACCES;
 613         if (retval)
 614                 goto out;
 615
 616         /*
 617          * Other scheduled or pending requests need to be canceled.  Small
 618          * optimization: If an autosuspend timer is running, leave it running
 619          * rather than cancelling it now only to restart it again in the near
 620          * future.
 621          */
 622         dev->power.request = RPM_REQ_NONE;
 623         if (!dev->power.timer_autosuspends)
 624                 pm_runtime_deactivate_timer(dev);
 625
 626         if (dev->power.runtime_status == RPM_ACTIVE) {
 627                 retval = 1;
 628                 goto out;
 629         }
 630
 631         if (dev->power.runtime_status == RPM_RESUMING
 632             || dev->power.runtime_status == RPM_SUSPENDING) {
 633                 DEFINE_WAIT(wait);
 634
 635                 if (rpmflags & (RPM_ASYNC | RPM_NOWAIT)) {
 636                         if (dev->power.runtime_status == RPM_SUSPENDING)
 637                                 dev->power.deferred_resume = true;
 638                         else
 639                                 retval = -EINPROGRESS;
 640                         goto out;
 641                 }
 642
 643                 if (dev->power.irq_safe) {
 644                         spin_unlock(&dev->power.lock);
 645
 646                         cpu_relax();
 647
 648                         spin_lock(&dev->power.lock);
 649                         goto repeat;
 650                 }
 651
 652                 /* Wait for the operation carried out in parallel with us. */
 653                 for (;;) {
 654                         prepare_to_wait(&dev->power.wait_queue, &wait,
 655                                         TASK_UNINTERRUPTIBLE);
 656                         if (dev->power.runtime_status != RPM_RESUMING
 657                             && dev->power.runtime_status != RPM_SUSPENDING)
 658                                 break;
 659
 660                         spin_unlock_irq(&dev->power.lock);
 661
 662                         schedule();
 663
 664                         spin_lock_irq(&dev->power.lock);
 665                 }
 666                 finish_wait(&dev->power.wait_queue, &wait);
 667                 goto repeat;
 668         }
 669
 670         /*
 671          * See if we can skip waking up the parent.  This is safe only if
 672          * power.no_callbacks is set, because otherwise we don't know whether
 673          * the resume will actually succeed.
 674          */
 675         if (dev->power.no_callbacks && !parent && dev->parent) {
 676                 spin_lock_nested(&dev->parent->power.lock, SINGLE_DEPTH_NESTING);
 677                 if (dev->parent->power.disable_depth > 0
 678                     || dev->parent->power.ignore_children
 679                     || dev->parent->power.runtime_status == RPM_ACTIVE) {
 680                         atomic_inc(&dev->parent->power.child_count);
 681                         spin_unlock(&dev->parent->power.lock);
 682                         retval = 1;
 683                         goto no_callback;       /* Assume success. */
 684                 }
 685                 spin_unlock(&dev->parent->power.lock);
 686         }
 687
 688         /* Carry out an asynchronous or a synchronous resume. */
 689         if (rpmflags & RPM_ASYNC) {
 690                 dev->power.request = RPM_REQ_RESUME;
 691                 if (!dev->power.request_pending) {
 692                         dev->power.request_pending = true;
 693                         queue_work(pm_wq, &dev->power.work);
 694                 }
 695                 retval = 0;
 696                 goto out;
 697         }
 698
 699         if (!parent && dev->parent) {
 700                 /*
 701                  * Increment the parent's usage counter and resume it if
 702                  * necessary.  Not needed if dev is irq-safe; then the
 703                  * parent is permanently resumed.
 704                  */
 705                 parent = dev->parent;
 706                 if (dev->power.irq_safe)
 707                         goto skip_parent;
 708                 spin_unlock(&dev->power.lock);
 709
 710                 pm_runtime_get_noresume(parent);
 711
 712                 spin_lock(&parent->power.lock);
 713                 /*
 714                  * We can resume if the parent's runtime PM is disabled or it
 715                  * is set to ignore children.
 716                  */
 717                 if (!parent->power.disable_depth
 718                     && !parent->power.ignore_children) {
 719                         rpm_resume(parent, 0);
 720                         if (parent->power.runtime_status != RPM_ACTIVE)
 721                                 retval = -EBUSY;
 722                 }
 723                 spin_unlock(&parent->power.lock);
 724
 725                 spin_lock(&dev->power.lock);
 726                 if (retval)
 727                         goto out;
 728                 goto repeat;
 729         }
 730  skip_parent:
 731
 732         if (dev->power.no_callbacks)
 733                 goto no_callback;       /* Assume success. */
 734
 735         __update_runtime_status(dev, RPM_RESUMING);
 736
 737         callback = RPM_GET_CALLBACK(dev, runtime_resume);
 738
 739         retval = rpm_callback(callback, dev);
 740         if (retval) {
 741                 __update_runtime_status(dev, RPM_SUSPENDED);
 742                 pm_runtime_cancel_pending(dev);
 743         } else {
 744  no_callback:
 745                 __update_runtime_status(dev, RPM_ACTIVE);
 746                 if (parent)
 747                         atomic_inc(&parent->power.child_count);
 748         }
 749         wake_up_all(&dev->power.wait_queue);
 750
 751         if (retval >= 0)
 752                 rpm_idle(dev, RPM_ASYNC);
 753
 754  out:
 755         if (parent && !dev->power.irq_safe) {
 756                 spin_unlock_irq(&dev->power.lock);
 757
 758                 pm_runtime_put(parent);
 759
 760                 spin_lock_irq(&dev->power.lock);
 761         }
 762
 763         trace_rpm_return_int(dev, _THIS_IP_, retval);
 764
 765         return retval;
 766 }
 767
 768 /**
 769  * pm_runtime_work - Universal runtime PM work function.
 770  * @work: Work structure used for scheduling the execution of this function.
 771  *
 772  * Use @work to get the device object the work is to be done for, determine what
 773  * is to be done and execute the appropriate runtime PM function.
 774  */
 775 static void pm_runtime_work(struct work_struct *work)
 776 {
 777         struct device *dev = container_of(work, struct device, power.work);
 778         enum rpm_request req;
 779
 780         spin_lock_irq(&dev->power.lock);
 781
 782         if (!dev->power.request_pending)
 783                 goto out;
 784
 785         req = dev->power.request;
 786         dev->power.request = RPM_REQ_NONE;
 787         dev->power.request_pending = false;
 788
 789         switch (req) {
 790         case RPM_REQ_NONE:
 791                 break;
 792         case RPM_REQ_IDLE:
 793                 rpm_idle(dev, RPM_NOWAIT);
 794                 break;
 795         case RPM_REQ_SUSPEND:
 796                 rpm_suspend(dev, RPM_NOWAIT);
 797                 break;
 798         case RPM_REQ_AUTOSUSPEND:
 799                 rpm_suspend(dev, RPM_NOWAIT | RPM_AUTO);
 800                 break;
 801         case RPM_REQ_RESUME:
 802                 rpm_resume(dev, RPM_NOWAIT);
 803                 break;
 804         }
 805
 806  out:
 807         spin_unlock_irq(&dev->power.lock);
 808 }
 809
 810 /**
 811  * pm_suspend_timer_fn - Timer function for pm_schedule_suspend().
 812  * @data: Device pointer passed by pm_schedule_suspend().
 813  *
 814  * Check if the time is right and queue a suspend request.
 815  */
 816 static void pm_suspend_timer_fn(unsigned long data)
 817 {
 818         struct device *dev = (struct device *)data;
 819         unsigned long flags;
 820         unsigned long expires;
 821
 822         spin_lock_irqsave(&dev->power.lock, flags);
 823
 824         expires = dev->power.timer_expires;
 825         /* If 'expire' is after 'jiffies' we've been called too early. */
 826         if (expires > 0 && !time_after(expires, jiffies)) {
 827                 dev->power.timer_expires = 0;
 828                 rpm_suspend(dev, dev->power.timer_autosuspends ?
 829                     (RPM_ASYNC | RPM_AUTO) : RPM_ASYNC);
 830         }
 831
 832         spin_unlock_irqrestore(&dev->power.lock, flags);
 833 }
 834
 835 /**
 836  * pm_schedule_suspend - Set up a timer to submit a suspend request in future.
 837  * @dev: Device to suspend.
 838  * @delay: Time to wait before submitting a suspend request, in milliseconds.
 839  */
 840 int pm_schedule_suspend(struct device *dev, unsigned int delay)
 841 {
 842         unsigned long flags;
 843         int retval;
 844
 845         spin_lock_irqsave(&dev->power.lock, flags);
 846
 847         if (!delay) {
 848                 retval = rpm_suspend(dev, RPM_ASYNC);
 849                 goto out;
 850         }
 851
 852         retval = rpm_check_suspend_allowed(dev);
 853         if (retval)
 854                 goto out;
 855
 856         /* Other scheduled or pending requests need to be canceled. */
 857         pm_runtime_cancel_pending(dev);
 858
 859         dev->power.timer_expires = jiffies + msecs_to_jiffies(delay);
 860         dev->power.timer_expires += !dev->power.timer_expires;
 861         dev->power.timer_autosuspends = 0;
 862         mod_timer(&dev->power.suspend_timer, dev->power.timer_expires);
 863
 864  out:
 865         spin_unlock_irqrestore(&dev->power.lock, flags);
 866
 867         return retval;
 868 }
 869 EXPORT_SYMBOL_GPL(pm_schedule_suspend);
 870
 871 /**
 872  * __pm_runtime_idle - Entry point for runtime idle operations.
 873  * @dev: Device to send idle notification for.
 874  * @rpmflags: Flag bits.
 875  *
 876  * If the RPM_GET_PUT flag is set, decrement the device's usage count and
 877  * return immediately if it is larger than zero.  Then carry out an idle
 878  * notification, either synchronous or asynchronous.
 879  *
 880  * This routine may be called in atomic context if the RPM_ASYNC flag is set,
 881  * or if pm_runtime_irq_safe() has been called.
 882  */
 883 int __pm_runtime_idle(struct device *dev, int rpmflags)
 884 {
 885         unsigned long flags;
 886         int retval;
 887
 888         might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe);
 889
 890         if (rpmflags & RPM_GET_PUT) {
 891                 if (!atomic_dec_and_test(&dev->power.usage_count))
 892                         return 0;
 893         }
 894
 895         spin_lock_irqsave(&dev->power.lock, flags);
 896         retval = rpm_idle(dev, rpmflags);
 897         spin_unlock_irqrestore(&dev->power.lock, flags);
 898
 899         return retval;
 900 }
 901 EXPORT_SYMBOL_GPL(__pm_runtime_idle);
 902
 903 /**
 904  * __pm_runtime_suspend - Entry point for runtime put/suspend operations.
 905  * @dev: Device to suspend.
 906  * @rpmflags: Flag bits.
 907  *
 908  * If the RPM_GET_PUT flag is set, decrement the device's usage count and
 909  * return immediately if it is larger than zero.  Then carry out a suspend,
 910  * either synchronous or asynchronous.
 911  *
 912  * This routine may be called in atomic context if the RPM_ASYNC flag is set,
 913  * or if pm_runtime_irq_safe() has been called.
 914  */
 915 int __pm_runtime_suspend(struct device *dev, int rpmflags)
 916 {
 917         unsigned long flags;
 918         int retval;
 919
 920         might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe);
 921
 922         if (rpmflags & RPM_GET_PUT) {
 923                 if (!atomic_dec_and_test(&dev->power.usage_count))
 924                         return 0;
 925         }
 926
 927         spin_lock_irqsave(&dev->power.lock, flags);
 928         retval = rpm_suspend(dev, rpmflags);
 929         spin_unlock_irqrestore(&dev->power.lock, flags);
 930
 931         return retval;
 932 }
 933 EXPORT_SYMBOL_GPL(__pm_runtime_suspend);
 934
 935 /**
 936  * __pm_runtime_resume - Entry point for runtime resume operations.
 937  * @dev: Device to resume.
 938  * @rpmflags: Flag bits.
 939  *
 940  * If the RPM_GET_PUT flag is set, increment the device's usage count.  Then
 941  * carry out a resume, either synchronous or asynchronous.
 942  *
 943  * This routine may be called in atomic context if the RPM_ASYNC flag is set,
 944  * or if pm_runtime_irq_safe() has been called.
 945  */
 946 int __pm_runtime_resume(struct device *dev, int rpmflags)
 947 {
 948         unsigned long flags;
 949         int retval;
 950
 951         might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe);
 952
 953         if (rpmflags & RPM_GET_PUT)
 954                 atomic_inc(&dev->power.usage_count);
 955
 956         spin_lock_irqsave(&dev->power.lock, flags);
 957         retval = rpm_resume(dev, rpmflags);
 958         spin_unlock_irqrestore(&dev->power.lock, flags);
 959
 960         return retval;
 961 }
 962 EXPORT_SYMBOL_GPL(__pm_runtime_resume);
 963
 964 /**
 965  * __pm_runtime_set_status - Set runtime PM status of a device.
 966  * @dev: Device to handle.
 967  * @status: New runtime PM status of the device.
 968  *
 969  * If runtime PM of the device is disabled or its power.runtime_error field is
 970  * different from zero, the status may be changed either to RPM_ACTIVE, or to
 971  * RPM_SUSPENDED, as long as that reflects the actual state of the device.
 972  * However, if the device has a parent and the parent is not active, and the
 973  * parent's power.ignore_children flag is unset, the device's status cannot be
 974  * set to RPM_ACTIVE, so -EBUSY is returned in that case.
 975  *
 976  * If successful, __pm_runtime_set_status() clears the power.runtime_error field
 977  * and the device parent's counter of unsuspended children is modified to
 978  * reflect the new status.  If the new status is RPM_SUSPENDED, an idle
 979  * notification request for the parent is submitted.
 980  */
 981 int __pm_runtime_set_status(struct device *dev, unsigned int status)
 982 {
 983         struct device *parent = dev->parent;
 984         unsigned long flags;
 985         bool notify_parent = false;
 986         int error = 0;
 987
 988         if (status != RPM_ACTIVE && status != RPM_SUSPENDED)
 989                 return -EINVAL;
 990
 991         spin_lock_irqsave(&dev->power.lock, flags);
 992
 993         if (!dev->power.runtime_error && !dev->power.disable_depth) {
 994                 error = -EAGAIN;
 995                 goto out;
 996         }
 997
 998         if (dev->power.runtime_status == status)
 999                 goto out_set;
1000
1001         if (status == RPM_SUSPENDED) {
1002                 /* It always is possible to set the status to 'suspended'. */
1003                 if (parent) {
1004                         atomic_add_unless(&parent->power.child_count, -1, 0);
1005                         notify_parent = !parent->power.ignore_children;
1006                 }
1007                 goto out_set;
1008         }
1009
1010         if (parent) {
1011                 spin_lock_nested(&parent->power.lock, SINGLE_DEPTH_NESTING);
1012
1013                 /*
1014                  * It is invalid to put an active child under a parent that is
1015                  * not active, has runtime PM enabled and the
1016                  * 'power.ignore_children' flag unset.
1017                  */
1018                 if (!parent->power.disable_depth
1019                     && !parent->power.ignore_children
1020                     && parent->power.runtime_status != RPM_ACTIVE)
1021                         error = -EBUSY;
1022                 else if (dev->power.runtime_status == RPM_SUSPENDED)
1023                         atomic_inc(&parent->power.child_count);
1024
1025                 spin_unlock(&parent->power.lock);
1026
1027                 if (error)
1028                         goto out;
1029         }
1030
1031  out_set:
1032         __update_runtime_status(dev, status);
1033         dev->power.runtime_error = 0;
1034  out:
1035         spin_unlock_irqrestore(&dev->power.lock, flags);
1036
1037         if (notify_parent)
1038                 pm_request_idle(parent);
1039
1040         return error;
1041 }
1042 EXPORT_SYMBOL_GPL(__pm_runtime_set_status);
1043
1044 /**
1045  * __pm_runtime_barrier - Cancel pending requests and wait for completions.
1046  * @dev: Device to handle.
1047  *
1048  * Flush all pending requests for the device from pm_wq and wait for all
1049  * runtime PM operations involving the device in progress to complete.
1050  *
1051  * Should be called under dev->power.lock with interrupts disabled.
1052  */
1053 static void __pm_runtime_barrier(struct device *dev)
1054 {
1055         pm_runtime_deactivate_timer(dev);
1056
1057         if (dev->power.request_pending) {
1058                 dev->power.request = RPM_REQ_NONE;
1059                 spin_unlock_irq(&dev->power.lock);
1060
1061                 cancel_work_sync(&dev->power.work);
1062
1063                 spin_lock_irq(&dev->power.lock);
1064                 dev->power.request_pending = false;
1065         }
1066
1067         if (dev->power.runtime_status == RPM_SUSPENDING
1068             || dev->power.runtime_status == RPM_RESUMING
1069             || dev->power.idle_notification) {
1070                 DEFINE_WAIT(wait);
1071
1072                 /* Suspend, wake-up or idle notification in progress. */
1073                 for (;;) {
1074                         prepare_to_wait(&dev->power.wait_queue, &wait,
1075                                         TASK_UNINTERRUPTIBLE);
1076                         if (dev->power.runtime_status != RPM_SUSPENDING
1077                             && dev->power.runtime_status != RPM_RESUMING
1078                             && !dev->power.idle_notification)
1079                                 break;
1080                         spin_unlock_irq(&dev->power.lock);
1081
1082                         schedule();
1083
1084                         spin_lock_irq(&dev->power.lock);
1085                 }
1086                 finish_wait(&dev->power.wait_queue, &wait);
1087         }
1088 }
1089
1090 /**
1091  * pm_runtime_barrier - Flush pending requests and wait for completions.
1092  * @dev: Device to handle.
1093  *
1094  * Prevent the device from being suspended by incrementing its usage counter and
1095  * if there's a pending resume request for the device, wake the device up.
1096  * Next, make sure that all pending requests for the device have been flushed
1097  * from pm_wq and wait for all runtime PM operations involving the device in
1098  * progress to complete.
1099  *
1100  * Return value:
1101  * 1, if there was a resume request pending and the device had to be woken up,
1102  * 0, otherwise
1103  */
1104 int pm_runtime_barrier(struct device *dev)
1105 {
1106         int retval = 0;
1107
1108         pm_runtime_get_noresume(dev);
1109         spin_lock_irq(&dev->power.lock);
1110
1111         if (dev->power.request_pending
1112             && dev->power.request == RPM_REQ_RESUME) {
1113                 rpm_resume(dev, 0);
1114                 retval = 1;
1115         }
1116
1117         __pm_runtime_barrier(dev);
1118
1119         spin_unlock_irq(&dev->power.lock);
1120         pm_runtime_put_noidle(dev);
1121
1122         return retval;
1123 }
1124 EXPORT_SYMBOL_GPL(pm_runtime_barrier);
1125
1126 /**
1127  * __pm_runtime_disable - Disable runtime PM of a device.
1128  * @dev: Device to handle.
1129  * @check_resume: If set, check if there's a resume request for the device.
1130  *
1131  * Increment power.disable_depth for the device and if it was zero previously,
1132  * cancel all pending runtime PM requests for the device and wait for all
1133  * operations in progress to complete.  The device can be either active or
1134  * suspended after its runtime PM has been disabled.
1135  *
1136  * If @check_resume is set and there's a resume request pending when
1137  * __pm_runtime_disable() is called and power.disable_depth is zero, the
1138  * function will wake up the device before disabling its runtime PM.
1139  */
1140 void __pm_runtime_disable(struct device *dev, bool check_resume)
1141 {
1142         spin_lock_irq(&dev->power.lock);
1143
1144         if (dev->power.disable_depth > 0) {
1145                 dev->power.disable_depth++;
1146                 goto out;
1147         }
1148
1149         /*
1150          * Wake up the device if there's a resume request pending, because that
1151          * means there probably is some I/O to process and disabling runtime PM
1152          * shouldn't prevent the device from processing the I/O.
1153          */
1154         if (check_resume && dev->power.request_pending
1155             && dev->power.request == RPM_REQ_RESUME) {
1156                 /*
1157                  * Prevent suspends and idle notifications from being carried
1158                  * out after we have woken up the device.
1159                  */
1160                 pm_runtime_get_noresume(dev);
1161
1162                 rpm_resume(dev, 0);
1163
1164                 pm_runtime_put_noidle(dev);
1165         }
1166
1167         if (!dev->power.disable_depth++)
1168                 __pm_runtime_barrier(dev);
1169
1170  out:
1171         spin_unlock_irq(&dev->power.lock);
1172 }
1173 EXPORT_SYMBOL_GPL(__pm_runtime_disable);
1174
1175 /**
1176  * pm_runtime_enable - Enable runtime PM of a device.
1177  * @dev: Device to handle.
1178  */
1179 void pm_runtime_enable(struct device *dev)
1180 {
1181         unsigned long flags;
1182
1183         spin_lock_irqsave(&dev->power.lock, flags);
1184
1185         if (dev->power.disable_depth > 0)
1186                 dev->power.disable_depth--;
1187         else
1188                 dev_warn(dev, "Unbalanced %s!\n", __func__);
1189
1190         spin_unlock_irqrestore(&dev->power.lock, flags);
1191 }
1192 EXPORT_SYMBOL_GPL(pm_runtime_enable);
1193
1194 /**
1195  * pm_runtime_forbid - Block runtime PM of a device.
1196  * @dev: Device to handle.
1197  *
1198  * Increase the device's usage count and clear its power.runtime_auto flag,
1199  * so that it cannot be suspended at run time until pm_runtime_allow() is called
1200  * for it.
1201  */
1202 void pm_runtime_forbid(struct device *dev)
1203 {
1204         spin_lock_irq(&dev->power.lock);
1205         if (!dev->power.runtime_auto)
1206                 goto out;
1207
1208         dev->power.runtime_auto = false;
1209         atomic_inc(&dev->power.usage_count);
1210         rpm_resume(dev, 0);
1211
1212  out:
1213         spin_unlock_irq(&dev->power.lock);
1214 }
1215 EXPORT_SYMBOL_GPL(pm_runtime_forbid);
1216
1217 /**
1218  * pm_runtime_allow - Unblock runtime PM of a device.
1219  * @dev: Device to handle.
1220  *
1221  * Decrease the device's usage count and set its power.runtime_auto flag.
1222  */
1223 void pm_runtime_allow(struct device *dev)
1224 {
1225         spin_lock_irq(&dev->power.lock);
1226         if (dev->power.runtime_auto)
1227                 goto out;
1228
1229         dev->power.runtime_auto = true;
1230         if (atomic_dec_and_test(&dev->power.usage_count))
1231                 rpm_idle(dev, RPM_AUTO);
1232
1233  out:
1234         spin_unlock_irq(&dev->power.lock);
1235 }
1236 EXPORT_SYMBOL_GPL(pm_runtime_allow);
1237
1238 /**
1239  * pm_runtime_no_callbacks - Ignore runtime PM callbacks for a device.
1240  * @dev: Device to handle.
1241  *
1242  * Set the power.no_callbacks flag, which tells the PM core that this
1243  * device is power-managed through its parent and has no runtime PM
1244  * callbacks of its own.  The runtime sysfs attributes will be removed.
1245  */
1246 void pm_runtime_no_callbacks(struct device *dev)
1247 {
1248         spin_lock_irq(&dev->power.lock);
1249         dev->power.no_callbacks = 1;
1250         spin_unlock_irq(&dev->power.lock);
1251         if (device_is_registered(dev))
1252                 rpm_sysfs_remove(dev);
1253 }
1254 EXPORT_SYMBOL_GPL(pm_runtime_no_callbacks);
1255
1256 /**
1257  * pm_runtime_irq_safe - Leave interrupts disabled during callbacks.
1258  * @dev: Device to handle
1259  *
1260  * Set the power.irq_safe flag, which tells the PM core that the
1261  * ->runtime_suspend() and ->runtime_resume() callbacks for this device should
1262  * always be invoked with the spinlock held and interrupts disabled.  It also
1263  * causes the parent's usage counter to be permanently incremented, preventing
1264  * the parent from runtime suspending -- otherwise an irq-safe child might have
1265  * to wait for a non-irq-safe parent.
1266  */
1267 void pm_runtime_irq_safe(struct device *dev)
1268 {
1269         if (dev->parent)
1270                 pm_runtime_get_sync(dev->parent);
1271         spin_lock_irq(&dev->power.lock);
1272         dev->power.irq_safe = 1;
1273         spin_unlock_irq(&dev->power.lock);
1274 }
1275 EXPORT_SYMBOL_GPL(pm_runtime_irq_safe);
1276
1277 /**
1278  * update_autosuspend - Handle a change to a device's autosuspend settings.
1279  * @dev: Device to handle.
1280  * @old_delay: The former autosuspend_delay value.
1281  * @old_use: The former use_autosuspend value.
1282  *
1283  * Prevent runtime suspend if the new delay is negative and use_autosuspend is
1284  * set; otherwise allow it.  Send an idle notification if suspends are allowed.
1285  *
1286  * This function must be called under dev->power.lock with interrupts disabled.
1287  */
1288 static void update_autosuspend(struct device *dev, int old_delay, int old_use)
1289 {
1290         int delay = dev->power.autosuspend_delay;
1291
1292         /* Should runtime suspend be prevented now? */
1293         if (dev->power.use_autosuspend && delay < 0) {
1294
1295                 /* If it used to be allowed then prevent it. */
1296                 if (!old_use || old_delay >= 0) {
1297                         atomic_inc(&dev->power.usage_count);
1298                         rpm_resume(dev, 0);
1299                 }
1300         }
1301
1302         /* Runtime suspend should be allowed now. */
1303         else {
1304
1305                 /* If it used to be prevented then allow it. */
1306                 if (old_use && old_delay < 0)
1307                         atomic_dec(&dev->power.usage_count);
1308
1309                 /* Maybe we can autosuspend now. */
1310                 rpm_idle(dev, RPM_AUTO);
1311         }
1312 }
1313
1314 /**
1315  * pm_runtime_set_autosuspend_delay - Set a device's autosuspend_delay value.
1316  * @dev: Device to handle.
1317  * @delay: Value of the new delay in milliseconds.
1318  *
1319  * Set the device's power.autosuspend_delay value.  If it changes to negative
1320  * and the power.use_autosuspend flag is set, prevent runtime suspends.  If it
1321  * changes the other way, allow runtime suspends.
1322  */
1323 void pm_runtime_set_autosuspend_delay(struct device *dev, int delay)
1324 {
1325         int old_delay, old_use;
1326
1327         spin_lock_irq(&dev->power.lock);
1328         old_delay = dev->power.autosuspend_delay;
1329         old_use = dev->power.use_autosuspend;
1330         dev->power.autosuspend_delay = delay;
1331         update_autosuspend(dev, old_delay, old_use);
1332         spin_unlock_irq(&dev->power.lock);
1333 }
1334 EXPORT_SYMBOL_GPL(pm_runtime_set_autosuspend_delay);
1335
1336 /**
1337  * __pm_runtime_use_autosuspend - Set a device's use_autosuspend flag.
1338  * @dev: Device to handle.
1339  * @use: New value for use_autosuspend.
1340  *
1341  * Set the device's power.use_autosuspend flag, and allow or prevent runtime
1342  * suspends as needed.
1343  */
1344 void __pm_runtime_use_autosuspend(struct device *dev, bool use)
1345 {
1346         int old_delay, old_use;
1347
1348         spin_lock_irq(&dev->power.lock);
1349         old_delay = dev->power.autosuspend_delay;
1350         old_use = dev->power.use_autosuspend;
1351         dev->power.use_autosuspend = use;
1352         update_autosuspend(dev, old_delay, old_use);
1353         spin_unlock_irq(&dev->power.lock);
1354 }
1355 EXPORT_SYMBOL_GPL(__pm_runtime_use_autosuspend);
1356
1357 /**
1358  * pm_runtime_init - Initialize runtime PM fields in given device object.
1359  * @dev: Device object to initialize.
1360  */
1361 void pm_runtime_init(struct device *dev)
1362 {
1363         dev->power.runtime_status = RPM_SUSPENDED;
1364         dev->power.idle_notification = false;
1365
1366         dev->power.disable_depth = 1;
1367         atomic_set(&dev->power.usage_count, 0);
1368
1369         dev->power.runtime_error = 0;
1370
1371         atomic_set(&dev->power.child_count, 0);
1372         pm_suspend_ignore_children(dev, false);
1373         dev->power.runtime_auto = true;
1374
1375         dev->power.request_pending = false;
1376         dev->power.request = RPM_REQ_NONE;
1377         dev->power.deferred_resume = false;
1378         dev->power.accounting_timestamp = jiffies;
1379         INIT_WORK(&dev->power.work, pm_runtime_work);
1380
1381         dev->power.timer_expires = 0;
1382         setup_timer(&dev->power.suspend_timer, pm_suspend_timer_fn,
1383                         (unsigned long)dev);
1384
1385         init_waitqueue_head(&dev->power.wait_queue);
1386 }
1387
1388 /**
1389  * pm_runtime_remove - Prepare for removing a device from device hierarchy.
1390  * @dev: Device object being removed from device hierarchy.
1391  */
1392 void pm_runtime_remove(struct device *dev)
1393 {
1394         __pm_runtime_disable(dev, false);
1395
1396         /* Change the status back to 'suspended' to match the initial status. */
1397         if (dev->power.runtime_status == RPM_ACTIVE)
1398                 pm_runtime_set_suspended(dev);
1399         if (dev->power.irq_safe && dev->parent)
1400                 pm_runtime_put(dev->parent);
1401 }
1402 #endif
1403
1404 /**
1405  * pm_runtime_force_suspend - Force a device into suspend state if needed.
1406  * @dev: Device to suspend.
1407  *
1408  * Disable runtime PM so we safely can check the device's runtime PM status and
1409  * if it is active, invoke it's .runtime_suspend callback to bring it into
1410  * suspend state. Keep runtime PM disabled to preserve the state unless we
1411  * encounter errors.
1412  *
1413  * Typically this function may be invoked from a system suspend callback to make
1414  * sure the device is put into low power state.
1415  */
1416 int pm_runtime_force_suspend(struct device *dev)
1417 {
1418         int (*callback)(struct device *);
1419         int ret = 0;
1420
1421         pm_runtime_disable(dev);
1422
1423         /*
1424          * Note that pm_runtime_status_suspended() returns false while
1425          * !CONFIG_PM_RUNTIME, which means the device will be put into low
1426          * power state.
1427          */
1428         if (pm_runtime_status_suspended(dev))
1429                 return 0;
1430
1431         callback = RPM_GET_CALLBACK(dev, runtime_suspend);
1432
1433         if (!callback) {
1434                 ret = -ENOSYS;
1435                 goto err;
1436         }
1437
1438         ret = callback(dev);
1439         if (ret)
1440                 goto err;
1441
1442         pm_runtime_set_suspended(dev);
1443         return 0;
1444 err:
1445         pm_runtime_enable(dev);
1446         return ret;
1447 }
1448 EXPORT_SYMBOL_GPL(pm_runtime_force_suspend);
1449
1450 /**
1451  * pm_runtime_force_resume - Force a device into resume state.
1452  * @dev: Device to resume.
1453  *
1454  * Prior invoking this function we expect the user to have brought the device
1455  * into low power state by a call to pm_runtime_force_suspend(). Here we reverse
1456  * those actions and brings the device into full power. We update the runtime PM
1457  * status and re-enables runtime PM.
1458  *
1459  * Typically this function may be invoked from a system resume callback to make
1460  * sure the device is put into full power state.
1461  */
1462 int pm_runtime_force_resume(struct device *dev)
1463 {
1464         int (*callback)(struct device *);
1465         int ret = 0;
1466
1467         callback = RPM_GET_CALLBACK(dev, runtime_resume);
1468
1469         if (!callback) {
1470                 ret = -ENOSYS;
1471                 goto out;
1472         }
1473
1474         ret = callback(dev);
1475         if (ret)
1476                 goto out;
1477
1478         pm_runtime_set_active(dev);
1479         pm_runtime_mark_last_busy(dev);
1480 out:
1481         pm_runtime_enable(dev);
1482         return ret;
1483 }
1484 EXPORT_SYMBOL_GPL(pm_runtime_force_resume);