drivers/base/power/runtime.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * drivers/base/power/runtime.c - Helper functions for device runtime PM
   4  *
   5  * Copyright (c) 2009 Rafael J. Wysocki <[email protected]>, Novell Inc.
   6  * Copyright (C) 2010 Alan Stern <[email protected]>
   7  */
   8 #include <linux/sched/mm.h>
   9 #include <linux/ktime.h>
  10 #include <linux/hrtimer.h>
  11 #include <linux/export.h>
  12 #include <linux/pm_runtime.h>
  13 #include <linux/pm_wakeirq.h>
  14 #include <trace/events/rpm.h>
  15
  16 #include "../base.h"
  17 #include "power.h"
  18
  19 typedef int (*pm_callback_t)(struct device *);
  20
  21 static pm_callback_t __rpm_get_callback(struct device *dev, size_t cb_offset)
  22 {
  23         pm_callback_t cb;
  24         const struct dev_pm_ops *ops;
  25
  26         if (dev->pm_domain)
  27                 ops = &dev->pm_domain->ops;
  28         else if (dev->type && dev->type->pm)
  29                 ops = dev->type->pm;
  30         else if (dev->class && dev->class->pm)
  31                 ops = dev->class->pm;
  32         else if (dev->bus && dev->bus->pm)
  33                 ops = dev->bus->pm;
  34         else
  35                 ops = NULL;
  36
  37         if (ops)
  38                 cb = *(pm_callback_t *)((void *)ops + cb_offset);
  39         else
  40                 cb = NULL;
  41
  42         if (!cb && dev->driver && dev->driver->pm)
  43                 cb = *(pm_callback_t *)((void *)dev->driver->pm + cb_offset);
  44
  45         return cb;
  46 }
  47
  48 #define RPM_GET_CALLBACK(dev, callback) \
  49                 __rpm_get_callback(dev, offsetof(struct dev_pm_ops, callback))
  50
  51 static int rpm_resume(struct device *dev, int rpmflags);
  52 static int rpm_suspend(struct device *dev, int rpmflags);
  53
  54 /**
  55  * update_pm_runtime_accounting - Update the time accounting of power states
  56  * @dev: Device to update the accounting for
  57  *
  58  * In order to be able to have time accounting of the various power states
  59  * (as used by programs such as PowerTOP to show the effectiveness of runtime
  60  * PM), we need to track the time spent in each state.
  61  * update_pm_runtime_accounting must be called each time before the
  62  * runtime_status field is updated, to account the time in the old state
  63  * correctly.
  64  */
  65 static void update_pm_runtime_accounting(struct device *dev)
  66 {
  67         u64 now, last, delta;
  68
  69         if (dev->power.disable_depth > 0)
  70                 return;
  71
  72         last = dev->power.accounting_timestamp;
  73
  74         now = ktime_get_mono_fast_ns();
  75         dev->power.accounting_timestamp = now;
  76
  77         /*
  78          * Because ktime_get_mono_fast_ns() is not monotonic during
  79          * timekeeping updates, ensure that 'now' is after the last saved
  80          * timesptamp.
  81          */
  82         if (now < last)
  83                 return;
  84
  85         delta = now - last;
  86
  87         if (dev->power.runtime_status == RPM_SUSPENDED)
  88                 dev->power.suspended_time += delta;
  89         else
  90                 dev->power.active_time += delta;
  91 }
  92
  93 static void __update_runtime_status(struct device *dev, enum rpm_status status)
  94 {
  95         update_pm_runtime_accounting(dev);
  96         dev->power.runtime_status = status;
  97 }
  98
  99 static u64 rpm_get_accounted_time(struct device *dev, bool suspended)
 100 {
 101         u64 time;
 102         unsigned long flags;
 103
 104         spin_lock_irqsave(&dev->power.lock, flags);
 105
 106         update_pm_runtime_accounting(dev);
 107         time = suspended ? dev->power.suspended_time : dev->power.active_time;
 108
 109         spin_unlock_irqrestore(&dev->power.lock, flags);
 110
 111         return time;
 112 }
 113
 114 u64 pm_runtime_active_time(struct device *dev)
 115 {
 116         return rpm_get_accounted_time(dev, false);
 117 }
 118
 119 u64 pm_runtime_suspended_time(struct device *dev)
 120 {
 121         return rpm_get_accounted_time(dev, true);
 122 }
 123 EXPORT_SYMBOL_GPL(pm_runtime_suspended_time);
 124
 125 /**
 126  * pm_runtime_deactivate_timer - Deactivate given device's suspend timer.
 127  * @dev: Device to handle.
 128  */
 129 static void pm_runtime_deactivate_timer(struct device *dev)
 130 {
 131         if (dev->power.timer_expires > 0) {
 132                 hrtimer_try_to_cancel(&dev->power.suspend_timer);
 133                 dev->power.timer_expires = 0;
 134         }
 135 }
 136
 137 /**
 138  * pm_runtime_cancel_pending - Deactivate suspend timer and cancel requests.
 139  * @dev: Device to handle.
 140  */
 141 static void pm_runtime_cancel_pending(struct device *dev)
 142 {
 143         pm_runtime_deactivate_timer(dev);
 144         /*
 145          * In case there's a request pending, make sure its work function will
 146          * return without doing anything.
 147          */
 148         dev->power.request = RPM_REQ_NONE;
 149 }
 150
 151 /*
 152  * pm_runtime_autosuspend_expiration - Get a device's autosuspend-delay expiration time.
 153  * @dev: Device to handle.
 154  *
 155  * Compute the autosuspend-delay expiration time based on the device's
 156  * power.last_busy time.  If the delay has already expired or is disabled
 157  * (negative) or the power.use_autosuspend flag isn't set, return 0.
 158  * Otherwise return the expiration time in nanoseconds (adjusted to be nonzero).
 159  *
 160  * This function may be called either with or without dev->power.lock held.
 161  * Either way it can be racy, since power.last_busy may be updated at any time.
 162  */
 163 u64 pm_runtime_autosuspend_expiration(struct device *dev)
 164 {
 165         int autosuspend_delay;
 166         u64 expires;
 167
 168         if (!dev->power.use_autosuspend)
 169                 return 0;
 170
 171         autosuspend_delay = READ_ONCE(dev->power.autosuspend_delay);
 172         if (autosuspend_delay < 0)
 173                 return 0;
 174
 175         expires  = READ_ONCE(dev->power.last_busy);
 176         expires += (u64)autosuspend_delay * NSEC_PER_MSEC;
 177         if (expires > ktime_get_mono_fast_ns())
 178                 return expires; /* Expires in the future */
 179
 180         return 0;
 181 }
 182 EXPORT_SYMBOL_GPL(pm_runtime_autosuspend_expiration);
 183
 184 static int dev_memalloc_noio(struct device *dev, void *data)
 185 {
 186         return dev->power.memalloc_noio;
 187 }
 188
 189 /*
 190  * pm_runtime_set_memalloc_noio - Set a device's memalloc_noio flag.
 191  * @dev: Device to handle.
 192  * @enable: True for setting the flag and False for clearing the flag.
 193  *
 194  * Set the flag for all devices in the path from the device to the
 195  * root device in the device tree if @enable is true, otherwise clear
 196  * the flag for devices in the path whose siblings don't set the flag.
 197  *
 198  * The function should only be called by block device, or network
 199  * device driver for solving the deadlock problem during runtime
 200  * resume/suspend:
 201  *
 202  *     If memory allocation with GFP_KERNEL is called inside runtime
 203  *     resume/suspend callback of any one of its ancestors(or the
 204  *     block device itself), the deadlock may be triggered inside the
 205  *     memory allocation since it might not complete until the block
 206  *     device becomes active and the involed page I/O finishes. The
 207  *     situation is pointed out first by Alan Stern. Network device
 208  *     are involved in iSCSI kind of situation.
 209  *
 210  * The lock of dev_hotplug_mutex is held in the function for handling
 211  * hotplug race because pm_runtime_set_memalloc_noio() may be called
 212  * in async probe().
 213  *
 214  * The function should be called between device_add() and device_del()
 215  * on the affected device(block/network device).
 216  */
 217 void pm_runtime_set_memalloc_noio(struct device *dev, bool enable)
 218 {
 219         static DEFINE_MUTEX(dev_hotplug_mutex);
 220
 221         mutex_lock(&dev_hotplug_mutex);
 222         for (;;) {
 223                 bool enabled;
 224
 225                 /* hold power lock since bitfield is not SMP-safe. */
 226                 spin_lock_irq(&dev->power.lock);
 227                 enabled = dev->power.memalloc_noio;
 228                 dev->power.memalloc_noio = enable;
 229                 spin_unlock_irq(&dev->power.lock);
 230
 231                 /*
 232                  * not need to enable ancestors any more if the device
 233                  * has been enabled.
 234                  */
 235                 if (enabled && enable)
 236                         break;
 237
 238                 dev = dev->parent;
 239
 240                 /*
 241                  * clear flag of the parent device only if all the
 242                  * children don't set the flag because ancestor's
 243                  * flag was set by any one of the descendants.
 244                  */
 245                 if (!dev || (!enable &&
 246                              device_for_each_child(dev, NULL,
 247                                                    dev_memalloc_noio)))
 248                         break;
 249         }
 250         mutex_unlock(&dev_hotplug_mutex);
 251 }
 252 EXPORT_SYMBOL_GPL(pm_runtime_set_memalloc_noio);
 253
 254 /**
 255  * rpm_check_suspend_allowed - Test whether a device may be suspended.
 256  * @dev: Device to test.
 257  */
 258 static int rpm_check_suspend_allowed(struct device *dev)
 259 {
 260         int retval = 0;
 261
 262         if (dev->power.runtime_error)
 263                 retval = -EINVAL;
 264         else if (dev->power.disable_depth > 0)
 265                 retval = -EACCES;
 266         else if (atomic_read(&dev->power.usage_count) > 0)
 267                 retval = -EAGAIN;
 268         else if (!dev->power.ignore_children &&
 269                         atomic_read(&dev->power.child_count))
 270                 retval = -EBUSY;
 271
 272         /* Pending resume requests take precedence over suspends. */
 273         else if ((dev->power.deferred_resume
 274                         && dev->power.runtime_status == RPM_SUSPENDING)
 275             || (dev->power.request_pending
 276                         && dev->power.request == RPM_REQ_RESUME))
 277                 retval = -EAGAIN;
 278         else if (__dev_pm_qos_resume_latency(dev) == 0)
 279                 retval = -EPERM;
 280         else if (dev->power.runtime_status == RPM_SUSPENDED)
 281                 retval = 1;
 282
 283         return retval;
 284 }
 285
 286 static int rpm_get_suppliers(struct device *dev)
 287 {
 288         struct device_link *link;
 289
 290         list_for_each_entry_rcu(link, &dev->links.suppliers, c_node,
 291                                 device_links_read_lock_held()) {
 292                 int retval;
 293
 294                 if (!(link->flags & DL_FLAG_PM_RUNTIME))
 295                         continue;
 296
 297                 retval = pm_runtime_get_sync(link->supplier);
 298                 /* Ignore suppliers with disabled runtime PM. */
 299                 if (retval < 0 && retval != -EACCES) {
 300                         pm_runtime_put_noidle(link->supplier);
 301                         return retval;
 302                 }
 303                 refcount_inc(&link->rpm_active);
 304         }
 305         return 0;
 306 }
 307
 308 static void rpm_put_suppliers(struct device *dev)
 309 {
 310         struct device_link *link;
 311
 312         list_for_each_entry_rcu(link, &dev->links.suppliers, c_node,
 313                                 device_links_read_lock_held()) {
 314
 315                 while (refcount_dec_not_one(&link->rpm_active))
 316                         pm_runtime_put(link->supplier);
 317         }
 318 }
 319
 320 /**
 321  * __rpm_callback - Run a given runtime PM callback for a given device.
 322  * @cb: Runtime PM callback to run.
 323  * @dev: Device to run the callback for.
 324  */
 325 static int __rpm_callback(int (*cb)(struct device *), struct device *dev)
 326         __releases(&dev->power.lock) __acquires(&dev->power.lock)
 327 {
 328         int retval, idx;
 329         bool use_links = dev->power.links_count > 0;
 330
 331         if (dev->power.irq_safe) {
 332                 spin_unlock(&dev->power.lock);
 333         } else {
 334                 spin_unlock_irq(&dev->power.lock);
 335
 336                 /*
 337                  * Resume suppliers if necessary.
 338                  *
 339                  * The device's runtime PM status cannot change until this
 340                  * routine returns, so it is safe to read the status outside of
 341                  * the lock.
 342                  */
 343                 if (use_links && dev->power.runtime_status == RPM_RESUMING) {
 344                         idx = device_links_read_lock();
 345
 346                         retval = rpm_get_suppliers(dev);
 347                         if (retval)
 348                                 goto fail;
 349
 350                         device_links_read_unlock(idx);
 351                 }
 352         }
 353
 354         retval = cb(dev);
 355
 356         if (dev->power.irq_safe) {
 357                 spin_lock(&dev->power.lock);
 358         } else {
 359                 /*
 360                  * If the device is suspending and the callback has returned
 361                  * success, drop the usage counters of the suppliers that have
 362                  * been reference counted on its resume.
 363                  *
 364                  * Do that if resume fails too.
 365                  */
 366                 if (use_links
 367                     && ((dev->power.runtime_status == RPM_SUSPENDING && !retval)
 368                     || (dev->power.runtime_status == RPM_RESUMING && retval))) {
 369                         idx = device_links_read_lock();
 370
 371  fail:
 372                         rpm_put_suppliers(dev);
 373
 374                         device_links_read_unlock(idx);
 375                 }
 376
 377                 spin_lock_irq(&dev->power.lock);
 378         }
 379
 380         return retval;
 381 }
 382
 383 /**
 384  * rpm_idle - Notify device bus type if the device can be suspended.
 385  * @dev: Device to notify the bus type about.
 386  * @rpmflags: Flag bits.
 387  *
 388  * Check if the device's runtime PM status allows it to be suspended.  If
 389  * another idle notification has been started earlier, return immediately.  If
 390  * the RPM_ASYNC flag is set then queue an idle-notification request; otherwise
 391  * run the ->runtime_idle() callback directly. If the ->runtime_idle callback
 392  * doesn't exist or if it returns 0, call rpm_suspend with the RPM_AUTO flag.
 393  *
 394  * This function must be called under dev->power.lock with interrupts disabled.
 395  */
 396 static int rpm_idle(struct device *dev, int rpmflags)
 397 {
 398         int (*callback)(struct device *);
 399         int retval;
 400
 401         trace_rpm_idle_rcuidle(dev, rpmflags);
 402         retval = rpm_check_suspend_allowed(dev);
 403         if (retval < 0)
 404                 ;       /* Conditions are wrong. */
 405
 406         /* Idle notifications are allowed only in the RPM_ACTIVE state. */
 407         else if (dev->power.runtime_status != RPM_ACTIVE)
 408                 retval = -EAGAIN;
 409
 410         /*
 411          * Any pending request other than an idle notification takes
 412          * precedence over us, except that the timer may be running.
 413          */
 414         else if (dev->power.request_pending &&
 415             dev->power.request > RPM_REQ_IDLE)
 416                 retval = -EAGAIN;
 417
 418         /* Act as though RPM_NOWAIT is always set. */
 419         else if (dev->power.idle_notification)
 420                 retval = -EINPROGRESS;
 421         if (retval)
 422                 goto out;
 423
 424         /* Pending requests need to be canceled. */
 425         dev->power.request = RPM_REQ_NONE;
 426
 427         if (dev->power.no_callbacks)
 428                 goto out;
 429
 430         /* Carry out an asynchronous or a synchronous idle notification. */
 431         if (rpmflags & RPM_ASYNC) {
 432                 dev->power.request = RPM_REQ_IDLE;
 433                 if (!dev->power.request_pending) {
 434                         dev->power.request_pending = true;
 435                         queue_work(pm_wq, &dev->power.work);
 436                 }
 437                 trace_rpm_return_int_rcuidle(dev, _THIS_IP_, 0);
 438                 return 0;
 439         }
 440
 441         dev->power.idle_notification = true;
 442
 443         callback = RPM_GET_CALLBACK(dev, runtime_idle);
 444
 445         if (callback)
 446                 retval = __rpm_callback(callback, dev);
 447
 448         dev->power.idle_notification = false;
 449         wake_up_all(&dev->power.wait_queue);
 450
 451  out:
 452         trace_rpm_return_int_rcuidle(dev, _THIS_IP_, retval);
 453         return retval ? retval : rpm_suspend(dev, rpmflags | RPM_AUTO);
 454 }
 455
 456 /**
 457  * rpm_callback - Run a given runtime PM callback for a given device.
 458  * @cb: Runtime PM callback to run.
 459  * @dev: Device to run the callback for.
 460  */
 461 static int rpm_callback(int (*cb)(struct device *), struct device *dev)
 462 {
 463         int retval;
 464
 465         if (!cb)
 466                 return -ENOSYS;
 467
 468         if (dev->power.memalloc_noio) {
 469                 unsigned int noio_flag;
 470
 471                 /*
 472                  * Deadlock might be caused if memory allocation with
 473                  * GFP_KERNEL happens inside runtime_suspend and
 474                  * runtime_resume callbacks of one block device's
 475                  * ancestor or the block device itself. Network
 476                  * device might be thought as part of iSCSI block
 477                  * device, so network device and its ancestor should
 478                  * be marked as memalloc_noio too.
 479                  */
 480                 noio_flag = memalloc_noio_save();
 481                 retval = __rpm_callback(cb, dev);
 482                 memalloc_noio_restore(noio_flag);
 483         } else {
 484                 retval = __rpm_callback(cb, dev);
 485         }
 486
 487         dev->power.runtime_error = retval;
 488         return retval != -EACCES ? retval : -EIO;
 489 }
 490
 491 /**
 492  * rpm_suspend - Carry out runtime suspend of given device.
 493  * @dev: Device to suspend.
 494  * @rpmflags: Flag bits.
 495  *
 496  * Check if the device's runtime PM status allows it to be suspended.
 497  * Cancel a pending idle notification, autosuspend or suspend. If
 498  * another suspend has been started earlier, either return immediately
 499  * or wait for it to finish, depending on the RPM_NOWAIT and RPM_ASYNC
 500  * flags. If the RPM_ASYNC flag is set then queue a suspend request;
 501  * otherwise run the ->runtime_suspend() callback directly. When
 502  * ->runtime_suspend succeeded, if a deferred resume was requested while
 503  * the callback was running then carry it out, otherwise send an idle
 504  * notification for its parent (if the suspend succeeded and both
 505  * ignore_children of parent->power and irq_safe of dev->power are not set).
 506  * If ->runtime_suspend failed with -EAGAIN or -EBUSY, and if the RPM_AUTO
 507  * flag is set and the next autosuspend-delay expiration time is in the
 508  * future, schedule another autosuspend attempt.
 509  *
 510  * This function must be called under dev->power.lock with interrupts disabled.
 511  */
 512 static int rpm_suspend(struct device *dev, int rpmflags)
 513         __releases(&dev->power.lock) __acquires(&dev->power.lock)
 514 {
 515         int (*callback)(struct device *);
 516         struct device *parent = NULL;
 517         int retval;
 518
 519         trace_rpm_suspend_rcuidle(dev, rpmflags);
 520
 521  repeat:
 522         retval = rpm_check_suspend_allowed(dev);
 523         if (retval < 0)
 524                 goto out;       /* Conditions are wrong. */
 525
 526         /* Synchronous suspends are not allowed in the RPM_RESUMING state. */
 527         if (dev->power.runtime_status == RPM_RESUMING && !(rpmflags & RPM_ASYNC))
 528                 retval = -EAGAIN;
 529         if (retval)
 530                 goto out;
 531
 532         /* If the autosuspend_delay time hasn't expired yet, reschedule. */
 533         if ((rpmflags & RPM_AUTO)
 534             && dev->power.runtime_status != RPM_SUSPENDING) {
 535                 u64 expires = pm_runtime_autosuspend_expiration(dev);
 536
 537                 if (expires != 0) {
 538                         /* Pending requests need to be canceled. */
 539                         dev->power.request = RPM_REQ_NONE;
 540
 541                         /*
 542                          * Optimization: If the timer is already running and is
 543                          * set to expire at or before the autosuspend delay,
 544                          * avoid the overhead of resetting it.  Just let it
 545                          * expire; pm_suspend_timer_fn() will take care of the
 546                          * rest.
 547                          */
 548                         if (!(dev->power.timer_expires &&
 549                                         dev->power.timer_expires <= expires)) {
 550                                 /*
 551                                  * We add a slack of 25% to gather wakeups
 552                                  * without sacrificing the granularity.
 553                                  */
 554                                 u64 slack = (u64)READ_ONCE(dev->power.autosuspend_delay) *
 555                                                     (NSEC_PER_MSEC >> 2);
 556
 557                                 dev->power.timer_expires = expires;
 558                                 hrtimer_start_range_ns(&dev->power.suspend_timer,
 559                                                 ns_to_ktime(expires),
 560                                                 slack,
 561                                                 HRTIMER_MODE_ABS);
 562                         }
 563                         dev->power.timer_autosuspends = 1;
 564                         goto out;
 565                 }
 566         }
 567
 568         /* Other scheduled or pending requests need to be canceled. */
 569         pm_runtime_cancel_pending(dev);
 570
 571         if (dev->power.runtime_status == RPM_SUSPENDING) {
 572                 DEFINE_WAIT(wait);
 573
 574                 if (rpmflags & (RPM_ASYNC | RPM_NOWAIT)) {
 575                         retval = -EINPROGRESS;
 576                         goto out;
 577                 }
 578
 579                 if (dev->power.irq_safe) {
 580                         spin_unlock(&dev->power.lock);
 581
 582                         cpu_relax();
 583
 584                         spin_lock(&dev->power.lock);
 585                         goto repeat;
 586                 }
 587
 588                 /* Wait for the other suspend running in parallel with us. */
 589                 for (;;) {
 590                         prepare_to_wait(&dev->power.wait_queue, &wait,
 591                                         TASK_UNINTERRUPTIBLE);
 592                         if (dev->power.runtime_status != RPM_SUSPENDING)
 593                                 break;
 594
 595                         spin_unlock_irq(&dev->power.lock);
 596
 597                         schedule();
 598
 599                         spin_lock_irq(&dev->power.lock);
 600                 }
 601                 finish_wait(&dev->power.wait_queue, &wait);
 602                 goto repeat;
 603         }
 604
 605         if (dev->power.no_callbacks)
 606                 goto no_callback;       /* Assume success. */
 607
 608         /* Carry out an asynchronous or a synchronous suspend. */
 609         if (rpmflags & RPM_ASYNC) {
 610                 dev->power.request = (rpmflags & RPM_AUTO) ?
 611                     RPM_REQ_AUTOSUSPEND : RPM_REQ_SUSPEND;
 612                 if (!dev->power.request_pending) {
 613                         dev->power.request_pending = true;
 614                         queue_work(pm_wq, &dev->power.work);
 615                 }
 616                 goto out;
 617         }
 618
 619         __update_runtime_status(dev, RPM_SUSPENDING);
 620
 621         callback = RPM_GET_CALLBACK(dev, runtime_suspend);
 622
 623         dev_pm_enable_wake_irq_check(dev, true);
 624         retval = rpm_callback(callback, dev);
 625         if (retval)
 626                 goto fail;
 627
 628  no_callback:
 629         __update_runtime_status(dev, RPM_SUSPENDED);
 630         pm_runtime_deactivate_timer(dev);
 631
 632         if (dev->parent) {
 633                 parent = dev->parent;
 634                 atomic_add_unless(&parent->power.child_count, -1, 0);
 635         }
 636         wake_up_all(&dev->power.wait_queue);
 637
 638         if (dev->power.deferred_resume) {
 639                 dev->power.deferred_resume = false;
 640                 rpm_resume(dev, 0);
 641                 retval = -EAGAIN;
 642                 goto out;
 643         }
 644
 645         /* Maybe the parent is now able to suspend. */
 646         if (parent && !parent->power.ignore_children && !dev->power.irq_safe) {
 647                 spin_unlock(&dev->power.lock);
 648
 649                 spin_lock(&parent->power.lock);
 650                 rpm_idle(parent, RPM_ASYNC);
 651                 spin_unlock(&parent->power.lock);
 652
 653                 spin_lock(&dev->power.lock);
 654         }
 655
 656  out:
 657         trace_rpm_return_int_rcuidle(dev, _THIS_IP_, retval);
 658
 659         return retval;
 660
 661  fail:
 662         dev_pm_disable_wake_irq_check(dev);
 663         __update_runtime_status(dev, RPM_ACTIVE);
 664         dev->power.deferred_resume = false;
 665         wake_up_all(&dev->power.wait_queue);
 666
 667         if (retval == -EAGAIN || retval == -EBUSY) {
 668                 dev->power.runtime_error = 0;
 669
 670                 /*
 671                  * If the callback routine failed an autosuspend, and
 672                  * if the last_busy time has been updated so that there
 673                  * is a new autosuspend expiration time, automatically
 674                  * reschedule another autosuspend.
 675                  */
 676                 if ((rpmflags & RPM_AUTO) &&
 677                     pm_runtime_autosuspend_expiration(dev) != 0)
 678                         goto repeat;
 679         } else {
 680                 pm_runtime_cancel_pending(dev);
 681         }
 682         goto out;
 683 }
 684
 685 /**
 686  * rpm_resume - Carry out runtime resume of given device.
 687  * @dev: Device to resume.
 688  * @rpmflags: Flag bits.
 689  *
 690  * Check if the device's runtime PM status allows it to be resumed.  Cancel
 691  * any scheduled or pending requests.  If another resume has been started
 692  * earlier, either return immediately or wait for it to finish, depending on the
 693  * RPM_NOWAIT and RPM_ASYNC flags.  Similarly, if there's a suspend running in
 694  * parallel with this function, either tell the other process to resume after
 695  * suspending (deferred_resume) or wait for it to finish.  If the RPM_ASYNC
 696  * flag is set then queue a resume request; otherwise run the
 697  * ->runtime_resume() callback directly.  Queue an idle notification for the
 698  * device if the resume succeeded.
 699  *
 700  * This function must be called under dev->power.lock with interrupts disabled.
 701  */
 702 static int rpm_resume(struct device *dev, int rpmflags)
 703         __releases(&dev->power.lock) __acquires(&dev->power.lock)
 704 {
 705         int (*callback)(struct device *);
 706         struct device *parent = NULL;
 707         int retval = 0;
 708
 709         trace_rpm_resume_rcuidle(dev, rpmflags);
 710
 711  repeat:
 712         if (dev->power.runtime_error)
 713                 retval = -EINVAL;
 714         else if (dev->power.disable_depth == 1 && dev->power.is_suspended
 715             && dev->power.runtime_status == RPM_ACTIVE)
 716                 retval = 1;
 717         else if (dev->power.disable_depth > 0)
 718                 retval = -EACCES;
 719         if (retval)
 720                 goto out;
 721
 722         /*
 723          * Other scheduled or pending requests need to be canceled.  Small
 724          * optimization: If an autosuspend timer is running, leave it running
 725          * rather than cancelling it now only to restart it again in the near
 726          * future.
 727          */
 728         dev->power.request = RPM_REQ_NONE;
 729         if (!dev->power.timer_autosuspends)
 730                 pm_runtime_deactivate_timer(dev);
 731
 732         if (dev->power.runtime_status == RPM_ACTIVE) {
 733                 retval = 1;
 734                 goto out;
 735         }
 736
 737         if (dev->power.runtime_status == RPM_RESUMING
 738             || dev->power.runtime_status == RPM_SUSPENDING) {
 739                 DEFINE_WAIT(wait);
 740
 741                 if (rpmflags & (RPM_ASYNC | RPM_NOWAIT)) {
 742                         if (dev->power.runtime_status == RPM_SUSPENDING)
 743                                 dev->power.deferred_resume = true;
 744                         else
 745                                 retval = -EINPROGRESS;
 746                         goto out;
 747                 }
 748
 749                 if (dev->power.irq_safe) {
 750                         spin_unlock(&dev->power.lock);
 751
 752                         cpu_relax();
 753
 754                         spin_lock(&dev->power.lock);
 755                         goto repeat;
 756                 }
 757
 758                 /* Wait for the operation carried out in parallel with us. */
 759                 for (;;) {
 760                         prepare_to_wait(&dev->power.wait_queue, &wait,
 761                                         TASK_UNINTERRUPTIBLE);
 762                         if (dev->power.runtime_status != RPM_RESUMING
 763                             && dev->power.runtime_status != RPM_SUSPENDING)
 764                                 break;
 765
 766                         spin_unlock_irq(&dev->power.lock);
 767
 768                         schedule();
 769
 770                         spin_lock_irq(&dev->power.lock);
 771                 }
 772                 finish_wait(&dev->power.wait_queue, &wait);
 773                 goto repeat;
 774         }
 775
 776         /*
 777          * See if we can skip waking up the parent.  This is safe only if
 778          * power.no_callbacks is set, because otherwise we don't know whether
 779          * the resume will actually succeed.
 780          */
 781         if (dev->power.no_callbacks && !parent && dev->parent) {
 782                 spin_lock_nested(&dev->parent->power.lock, SINGLE_DEPTH_NESTING);
 783                 if (dev->parent->power.disable_depth > 0
 784                     || dev->parent->power.ignore_children
 785                     || dev->parent->power.runtime_status == RPM_ACTIVE) {
 786                         atomic_inc(&dev->parent->power.child_count);
 787                         spin_unlock(&dev->parent->power.lock);
 788                         retval = 1;
 789                         goto no_callback;       /* Assume success. */
 790                 }
 791                 spin_unlock(&dev->parent->power.lock);
 792         }
 793
 794         /* Carry out an asynchronous or a synchronous resume. */
 795         if (rpmflags & RPM_ASYNC) {
 796                 dev->power.request = RPM_REQ_RESUME;
 797                 if (!dev->power.request_pending) {
 798                         dev->power.request_pending = true;
 799                         queue_work(pm_wq, &dev->power.work);
 800                 }
 801                 retval = 0;
 802                 goto out;
 803         }
 804
 805         if (!parent && dev->parent) {
 806                 /*
 807                  * Increment the parent's usage counter and resume it if
 808                  * necessary.  Not needed if dev is irq-safe; then the
 809                  * parent is permanently resumed.
 810                  */
 811                 parent = dev->parent;
 812                 if (dev->power.irq_safe)
 813                         goto skip_parent;
 814                 spin_unlock(&dev->power.lock);
 815
 816                 pm_runtime_get_noresume(parent);
 817
 818                 spin_lock(&parent->power.lock);
 819                 /*
 820                  * Resume the parent if it has runtime PM enabled and not been
 821                  * set to ignore its children.
 822                  */
 823                 if (!parent->power.disable_depth
 824                     && !parent->power.ignore_children) {
 825                         rpm_resume(parent, 0);
 826                         if (parent->power.runtime_status != RPM_ACTIVE)
 827                                 retval = -EBUSY;
 828                 }
 829                 spin_unlock(&parent->power.lock);
 830
 831                 spin_lock(&dev->power.lock);
 832                 if (retval)
 833                         goto out;
 834                 goto repeat;
 835         }
 836  skip_parent:
 837
 838         if (dev->power.no_callbacks)
 839                 goto no_callback;       /* Assume success. */
 840
 841         __update_runtime_status(dev, RPM_RESUMING);
 842
 843         callback = RPM_GET_CALLBACK(dev, runtime_resume);
 844
 845         dev_pm_disable_wake_irq_check(dev);
 846         retval = rpm_callback(callback, dev);
 847         if (retval) {
 848                 __update_runtime_status(dev, RPM_SUSPENDED);
 849                 pm_runtime_cancel_pending(dev);
 850                 dev_pm_enable_wake_irq_check(dev, false);
 851         } else {
 852  no_callback:
 853                 __update_runtime_status(dev, RPM_ACTIVE);
 854                 pm_runtime_mark_last_busy(dev);
 855                 if (parent)
 856                         atomic_inc(&parent->power.child_count);
 857         }
 858         wake_up_all(&dev->power.wait_queue);
 859
 860         if (retval >= 0)
 861                 rpm_idle(dev, RPM_ASYNC);
 862
 863  out:
 864         if (parent && !dev->power.irq_safe) {
 865                 spin_unlock_irq(&dev->power.lock);
 866
 867                 pm_runtime_put(parent);
 868
 869                 spin_lock_irq(&dev->power.lock);
 870         }
 871
 872         trace_rpm_return_int_rcuidle(dev, _THIS_IP_, retval);
 873
 874         return retval;
 875 }
 876
 877 /**
 878  * pm_runtime_work - Universal runtime PM work function.
 879  * @work: Work structure used for scheduling the execution of this function.
 880  *
 881  * Use @work to get the device object the work is to be done for, determine what
 882  * is to be done and execute the appropriate runtime PM function.
 883  */
 884 static void pm_runtime_work(struct work_struct *work)
 885 {
 886         struct device *dev = container_of(work, struct device, power.work);
 887         enum rpm_request req;
 888
 889         spin_lock_irq(&dev->power.lock);
 890
 891         if (!dev->power.request_pending)
 892                 goto out;
 893
 894         req = dev->power.request;
 895         dev->power.request = RPM_REQ_NONE;
 896         dev->power.request_pending = false;
 897
 898         switch (req) {
 899         case RPM_REQ_NONE:
 900                 break;
 901         case RPM_REQ_IDLE:
 902                 rpm_idle(dev, RPM_NOWAIT);
 903                 break;
 904         case RPM_REQ_SUSPEND:
 905                 rpm_suspend(dev, RPM_NOWAIT);
 906                 break;
 907         case RPM_REQ_AUTOSUSPEND:
 908                 rpm_suspend(dev, RPM_NOWAIT | RPM_AUTO);
 909                 break;
 910         case RPM_REQ_RESUME:
 911                 rpm_resume(dev, RPM_NOWAIT);
 912                 break;
 913         }
 914
 915  out:
 916         spin_unlock_irq(&dev->power.lock);
 917 }
 918
 919 /**
 920  * pm_suspend_timer_fn - Timer function for pm_schedule_suspend().
 921  * @data: Device pointer passed by pm_schedule_suspend().
 922  *
 923  * Check if the time is right and queue a suspend request.
 924  */
 925 static enum hrtimer_restart  pm_suspend_timer_fn(struct hrtimer *timer)
 926 {
 927         struct device *dev = container_of(timer, struct device, power.suspend_timer);
 928         unsigned long flags;
 929         u64 expires;
 930
 931         spin_lock_irqsave(&dev->power.lock, flags);
 932
 933         expires = dev->power.timer_expires;
 934         /*
 935          * If 'expires' is after the current time, we've been called
 936          * too early.
 937          */
 938         if (expires > 0 && expires < ktime_get_mono_fast_ns()) {
 939                 dev->power.timer_expires = 0;
 940                 rpm_suspend(dev, dev->power.timer_autosuspends ?
 941                     (RPM_ASYNC | RPM_AUTO) : RPM_ASYNC);
 942         }
 943
 944         spin_unlock_irqrestore(&dev->power.lock, flags);
 945
 946         return HRTIMER_NORESTART;
 947 }
 948
 949 /**
 950  * pm_schedule_suspend - Set up a timer to submit a suspend request in future.
 951  * @dev: Device to suspend.
 952  * @delay: Time to wait before submitting a suspend request, in milliseconds.
 953  */
 954 int pm_schedule_suspend(struct device *dev, unsigned int delay)
 955 {
 956         unsigned long flags;
 957         u64 expires;
 958         int retval;
 959
 960         spin_lock_irqsave(&dev->power.lock, flags);
 961
 962         if (!delay) {
 963                 retval = rpm_suspend(dev, RPM_ASYNC);
 964                 goto out;
 965         }
 966
 967         retval = rpm_check_suspend_allowed(dev);
 968         if (retval)
 969                 goto out;
 970
 971         /* Other scheduled or pending requests need to be canceled. */
 972         pm_runtime_cancel_pending(dev);
 973
 974         expires = ktime_get_mono_fast_ns() + (u64)delay * NSEC_PER_MSEC;
 975         dev->power.timer_expires = expires;
 976         dev->power.timer_autosuspends = 0;
 977         hrtimer_start(&dev->power.suspend_timer, expires, HRTIMER_MODE_ABS);
 978
 979  out:
 980         spin_unlock_irqrestore(&dev->power.lock, flags);
 981
 982         return retval;
 983 }
 984 EXPORT_SYMBOL_GPL(pm_schedule_suspend);
 985
 986 /**
 987  * __pm_runtime_idle - Entry point for runtime idle operations.
 988  * @dev: Device to send idle notification for.
 989  * @rpmflags: Flag bits.
 990  *
 991  * If the RPM_GET_PUT flag is set, decrement the device's usage count and
 992  * return immediately if it is larger than zero.  Then carry out an idle
 993  * notification, either synchronous or asynchronous.
 994  *
 995  * This routine may be called in atomic context if the RPM_ASYNC flag is set,
 996  * or if pm_runtime_irq_safe() has been called.
 997  */
 998 int __pm_runtime_idle(struct device *dev, int rpmflags)
 999 {
1000         unsigned long flags;
1001         int retval;
1002
1003         if (rpmflags & RPM_GET_PUT) {
1004                 if (!atomic_dec_and_test(&dev->power.usage_count)) {
1005                         trace_rpm_usage_rcuidle(dev, rpmflags);
1006                         return 0;
1007                 }
1008         }
1009
1010         might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe);
1011
1012         spin_lock_irqsave(&dev->power.lock, flags);
1013         retval = rpm_idle(dev, rpmflags);
1014         spin_unlock_irqrestore(&dev->power.lock, flags);
1015
1016         return retval;
1017 }
1018 EXPORT_SYMBOL_GPL(__pm_runtime_idle);
1019
1020 /**
1021  * __pm_runtime_suspend - Entry point for runtime put/suspend operations.
1022  * @dev: Device to suspend.
1023  * @rpmflags: Flag bits.
1024  *
1025  * If the RPM_GET_PUT flag is set, decrement the device's usage count and
1026  * return immediately if it is larger than zero.  Then carry out a suspend,
1027  * either synchronous or asynchronous.
1028  *
1029  * This routine may be called in atomic context if the RPM_ASYNC flag is set,
1030  * or if pm_runtime_irq_safe() has been called.
1031  */
1032 int __pm_runtime_suspend(struct device *dev, int rpmflags)
1033 {
1034         unsigned long flags;
1035         int retval;
1036
1037         if (rpmflags & RPM_GET_PUT) {
1038                 if (!atomic_dec_and_test(&dev->power.usage_count)) {
1039                         trace_rpm_usage_rcuidle(dev, rpmflags);
1040                         return 0;
1041                 }
1042         }
1043
1044         might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe);
1045
1046         spin_lock_irqsave(&dev->power.lock, flags);
1047         retval = rpm_suspend(dev, rpmflags);
1048         spin_unlock_irqrestore(&dev->power.lock, flags);
1049
1050         return retval;
1051 }
1052 EXPORT_SYMBOL_GPL(__pm_runtime_suspend);
1053
1054 /**
1055  * __pm_runtime_resume - Entry point for runtime resume operations.
1056  * @dev: Device to resume.
1057  * @rpmflags: Flag bits.
1058  *
1059  * If the RPM_GET_PUT flag is set, increment the device's usage count.  Then
1060  * carry out a resume, either synchronous or asynchronous.
1061  *
1062  * This routine may be called in atomic context if the RPM_ASYNC flag is set,
1063  * or if pm_runtime_irq_safe() has been called.
1064  */
1065 int __pm_runtime_resume(struct device *dev, int rpmflags)
1066 {
1067         unsigned long flags;
1068         int retval;
1069
1070         might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe &&
1071                         dev->power.runtime_status != RPM_ACTIVE);
1072
1073         if (rpmflags & RPM_GET_PUT)
1074                 atomic_inc(&dev->power.usage_count);
1075
1076         spin_lock_irqsave(&dev->power.lock, flags);
1077         retval = rpm_resume(dev, rpmflags);
1078         spin_unlock_irqrestore(&dev->power.lock, flags);
1079
1080         return retval;
1081 }
1082 EXPORT_SYMBOL_GPL(__pm_runtime_resume);
1083
1084 /**
1085  * pm_runtime_get_if_active - Conditionally bump up device usage counter.
1086  * @dev: Device to handle.
1087  * @ign_usage_count: Whether or not to look at the current usage counter value.
1088  *
1089  * Return -EINVAL if runtime PM is disabled for @dev.
1090  *
1091  * Otherwise, if the runtime PM status of @dev is %RPM_ACTIVE and either
1092  * @ign_usage_count is %true or the runtime PM usage counter of @dev is not
1093  * zero, increment the usage counter of @dev and return 1. Otherwise, return 0
1094  * without changing the usage counter.
1095  *
1096  * If @ign_usage_count is %true, this function can be used to prevent suspending
1097  * the device when its runtime PM status is %RPM_ACTIVE.
1098  *
1099  * If @ign_usage_count is %false, this function can be used to prevent
1100  * suspending the device when both its runtime PM status is %RPM_ACTIVE and its
1101  * runtime PM usage counter is not zero.
1102  *
1103  * The caller is resposible for decrementing the runtime PM usage counter of
1104  * @dev after this function has returned a positive value for it.
1105  */
1106 int pm_runtime_get_if_active(struct device *dev, bool ign_usage_count)
1107 {
1108         unsigned long flags;
1109         int retval;
1110
1111         spin_lock_irqsave(&dev->power.lock, flags);
1112         if (dev->power.disable_depth > 0) {
1113                 retval = -EINVAL;
1114         } else if (dev->power.runtime_status != RPM_ACTIVE) {
1115                 retval = 0;
1116         } else if (ign_usage_count) {
1117                 retval = 1;
1118                 atomic_inc(&dev->power.usage_count);
1119         } else {
1120                 retval = atomic_inc_not_zero(&dev->power.usage_count);
1121         }
1122         trace_rpm_usage_rcuidle(dev, 0);
1123         spin_unlock_irqrestore(&dev->power.lock, flags);
1124
1125         return retval;
1126 }
1127 EXPORT_SYMBOL_GPL(pm_runtime_get_if_active);
1128
1129 /**
1130  * __pm_runtime_set_status - Set runtime PM status of a device.
1131  * @dev: Device to handle.
1132  * @status: New runtime PM status of the device.
1133  *
1134  * If runtime PM of the device is disabled or its power.runtime_error field is
1135  * different from zero, the status may be changed either to RPM_ACTIVE, or to
1136  * RPM_SUSPENDED, as long as that reflects the actual state of the device.
1137  * However, if the device has a parent and the parent is not active, and the
1138  * parent's power.ignore_children flag is unset, the device's status cannot be
1139  * set to RPM_ACTIVE, so -EBUSY is returned in that case.
1140  *
1141  * If successful, __pm_runtime_set_status() clears the power.runtime_error field
1142  * and the device parent's counter of unsuspended children is modified to
1143  * reflect the new status.  If the new status is RPM_SUSPENDED, an idle
1144  * notification request for the parent is submitted.
1145  *
1146  * If @dev has any suppliers (as reflected by device links to them), and @status
1147  * is RPM_ACTIVE, they will be activated upfront and if the activation of one
1148  * of them fails, the status of @dev will be changed to RPM_SUSPENDED (instead
1149  * of the @status value) and the suppliers will be deacticated on exit.  The
1150  * error returned by the failing supplier activation will be returned in that
1151  * case.
1152  */
1153 int __pm_runtime_set_status(struct device *dev, unsigned int status)
1154 {
1155         struct device *parent = dev->parent;
1156         bool notify_parent = false;
1157         int error = 0;
1158
1159         if (status != RPM_ACTIVE && status != RPM_SUSPENDED)
1160                 return -EINVAL;
1161
1162         spin_lock_irq(&dev->power.lock);
1163
1164         /*
1165          * Prevent PM-runtime from being enabled for the device or return an
1166          * error if it is enabled already and working.
1167          */
1168         if (dev->power.runtime_error || dev->power.disable_depth)
1169                 dev->power.disable_depth++;
1170         else
1171                 error = -EAGAIN;
1172
1173         spin_unlock_irq(&dev->power.lock);
1174
1175         if (error)
1176                 return error;
1177
1178         /*
1179          * If the new status is RPM_ACTIVE, the suppliers can be activated
1180          * upfront regardless of the current status, because next time
1181          * rpm_put_suppliers() runs, the rpm_active refcounts of the links
1182          * involved will be dropped down to one anyway.
1183          */
1184         if (status == RPM_ACTIVE) {
1185                 int idx = device_links_read_lock();
1186
1187                 error = rpm_get_suppliers(dev);
1188                 if (error)
1189                         status = RPM_SUSPENDED;
1190
1191                 device_links_read_unlock(idx);
1192         }
1193
1194         spin_lock_irq(&dev->power.lock);
1195
1196         if (dev->power.runtime_status == status || !parent)
1197                 goto out_set;
1198
1199         if (status == RPM_SUSPENDED) {
1200                 atomic_add_unless(&parent->power.child_count, -1, 0);
1201                 notify_parent = !parent->power.ignore_children;
1202         } else {
1203                 spin_lock_nested(&parent->power.lock, SINGLE_DEPTH_NESTING);
1204
1205                 /*
1206                  * It is invalid to put an active child under a parent that is
1207                  * not active, has runtime PM enabled and the
1208                  * 'power.ignore_children' flag unset.
1209                  */
1210                 if (!parent->power.disable_depth
1211                     && !parent->power.ignore_children
1212                     && parent->power.runtime_status != RPM_ACTIVE) {
1213                         dev_err(dev, "runtime PM trying to activate child device %s but parent (%s) is not active\n",
1214                                 dev_name(dev),
1215                                 dev_name(parent));
1216                         error = -EBUSY;
1217                 } else if (dev->power.runtime_status == RPM_SUSPENDED) {
1218                         atomic_inc(&parent->power.child_count);
1219                 }
1220
1221                 spin_unlock(&parent->power.lock);
1222
1223                 if (error) {
1224                         status = RPM_SUSPENDED;
1225                         goto out;
1226                 }
1227         }
1228
1229  out_set:
1230         __update_runtime_status(dev, status);
1231         if (!error)
1232                 dev->power.runtime_error = 0;
1233
1234  out:
1235         spin_unlock_irq(&dev->power.lock);
1236
1237         if (notify_parent)
1238                 pm_request_idle(parent);
1239
1240         if (status == RPM_SUSPENDED) {
1241                 int idx = device_links_read_lock();
1242
1243                 rpm_put_suppliers(dev);
1244
1245                 device_links_read_unlock(idx);
1246         }
1247
1248         pm_runtime_enable(dev);
1249
1250         return error;
1251 }
1252 EXPORT_SYMBOL_GPL(__pm_runtime_set_status);
1253
1254 /**
1255  * __pm_runtime_barrier - Cancel pending requests and wait for completions.
1256  * @dev: Device to handle.
1257  *
1258  * Flush all pending requests for the device from pm_wq and wait for all
1259  * runtime PM operations involving the device in progress to complete.
1260  *
1261  * Should be called under dev->power.lock with interrupts disabled.
1262  */
1263 static void __pm_runtime_barrier(struct device *dev)
1264 {
1265         pm_runtime_deactivate_timer(dev);
1266
1267         if (dev->power.request_pending) {
1268                 dev->power.request = RPM_REQ_NONE;
1269                 spin_unlock_irq(&dev->power.lock);
1270
1271                 cancel_work_sync(&dev->power.work);
1272
1273                 spin_lock_irq(&dev->power.lock);
1274                 dev->power.request_pending = false;
1275         }
1276
1277         if (dev->power.runtime_status == RPM_SUSPENDING
1278             || dev->power.runtime_status == RPM_RESUMING
1279             || dev->power.idle_notification) {
1280                 DEFINE_WAIT(wait);
1281
1282                 /* Suspend, wake-up or idle notification in progress. */
1283                 for (;;) {
1284                         prepare_to_wait(&dev->power.wait_queue, &wait,
1285                                         TASK_UNINTERRUPTIBLE);
1286                         if (dev->power.runtime_status != RPM_SUSPENDING
1287                             && dev->power.runtime_status != RPM_RESUMING
1288                             && !dev->power.idle_notification)
1289                                 break;
1290                         spin_unlock_irq(&dev->power.lock);
1291
1292                         schedule();
1293
1294                         spin_lock_irq(&dev->power.lock);
1295                 }
1296                 finish_wait(&dev->power.wait_queue, &wait);
1297         }
1298 }
1299
1300 /**
1301  * pm_runtime_barrier - Flush pending requests and wait for completions.
1302  * @dev: Device to handle.
1303  *
1304  * Prevent the device from being suspended by incrementing its usage counter and
1305  * if there's a pending resume request for the device, wake the device up.
1306  * Next, make sure that all pending requests for the device have been flushed
1307  * from pm_wq and wait for all runtime PM operations involving the device in
1308  * progress to complete.
1309  *
1310  * Return value:
1311  * 1, if there was a resume request pending and the device had to be woken up,
1312  * 0, otherwise
1313  */
1314 int pm_runtime_barrier(struct device *dev)
1315 {
1316         int retval = 0;
1317
1318         pm_runtime_get_noresume(dev);
1319         spin_lock_irq(&dev->power.lock);
1320
1321         if (dev->power.request_pending
1322             && dev->power.request == RPM_REQ_RESUME) {
1323                 rpm_resume(dev, 0);
1324                 retval = 1;
1325         }
1326
1327         __pm_runtime_barrier(dev);
1328
1329         spin_unlock_irq(&dev->power.lock);
1330         pm_runtime_put_noidle(dev);
1331
1332         return retval;
1333 }
1334 EXPORT_SYMBOL_GPL(pm_runtime_barrier);
1335
1336 /**
1337  * __pm_runtime_disable - Disable runtime PM of a device.
1338  * @dev: Device to handle.
1339  * @check_resume: If set, check if there's a resume request for the device.
1340  *
1341  * Increment power.disable_depth for the device and if it was zero previously,
1342  * cancel all pending runtime PM requests for the device and wait for all
1343  * operations in progress to complete.  The device can be either active or
1344  * suspended after its runtime PM has been disabled.
1345  *
1346  * If @check_resume is set and there's a resume request pending when
1347  * __pm_runtime_disable() is called and power.disable_depth is zero, the
1348  * function will wake up the device before disabling its runtime PM.
1349  */
1350 void __pm_runtime_disable(struct device *dev, bool check_resume)
1351 {
1352         spin_lock_irq(&dev->power.lock);
1353
1354         if (dev->power.disable_depth > 0) {
1355                 dev->power.disable_depth++;
1356                 goto out;
1357         }
1358
1359         /*
1360          * Wake up the device if there's a resume request pending, because that
1361          * means there probably is some I/O to process and disabling runtime PM
1362          * shouldn't prevent the device from processing the I/O.
1363          */
1364         if (check_resume && dev->power.request_pending
1365             && dev->power.request == RPM_REQ_RESUME) {
1366                 /*
1367                  * Prevent suspends and idle notifications from being carried
1368                  * out after we have woken up the device.
1369                  */
1370                 pm_runtime_get_noresume(dev);
1371
1372                 rpm_resume(dev, 0);
1373
1374                 pm_runtime_put_noidle(dev);
1375         }
1376
1377         /* Update time accounting before disabling PM-runtime. */
1378         update_pm_runtime_accounting(dev);
1379
1380         if (!dev->power.disable_depth++)
1381                 __pm_runtime_barrier(dev);
1382
1383  out:
1384         spin_unlock_irq(&dev->power.lock);
1385 }
1386 EXPORT_SYMBOL_GPL(__pm_runtime_disable);
1387
1388 /**
1389  * pm_runtime_enable - Enable runtime PM of a device.
1390  * @dev: Device to handle.
1391  */
1392 void pm_runtime_enable(struct device *dev)
1393 {
1394         unsigned long flags;
1395
1396         spin_lock_irqsave(&dev->power.lock, flags);
1397
1398         if (dev->power.disable_depth > 0) {
1399                 dev->power.disable_depth--;
1400
1401                 /* About to enable runtime pm, set accounting_timestamp to now */
1402                 if (!dev->power.disable_depth)
1403                         dev->power.accounting_timestamp = ktime_get_mono_fast_ns();
1404         } else {
1405                 dev_warn(dev, "Unbalanced %s!\n", __func__);
1406         }
1407
1408         WARN(!dev->power.disable_depth &&
1409              dev->power.runtime_status == RPM_SUSPENDED &&
1410              !dev->power.ignore_children &&
1411              atomic_read(&dev->power.child_count) > 0,
1412              "Enabling runtime PM for inactive device (%s) with active children\n",
1413              dev_name(dev));
1414
1415         spin_unlock_irqrestore(&dev->power.lock, flags);
1416 }
1417 EXPORT_SYMBOL_GPL(pm_runtime_enable);
1418
1419 /**
1420  * pm_runtime_forbid - Block runtime PM of a device.
1421  * @dev: Device to handle.
1422  *
1423  * Increase the device's usage count and clear its power.runtime_auto flag,
1424  * so that it cannot be suspended at run time until pm_runtime_allow() is called
1425  * for it.
1426  */
1427 void pm_runtime_forbid(struct device *dev)
1428 {
1429         spin_lock_irq(&dev->power.lock);
1430         if (!dev->power.runtime_auto)
1431                 goto out;
1432
1433         dev->power.runtime_auto = false;
1434         atomic_inc(&dev->power.usage_count);
1435         rpm_resume(dev, 0);
1436
1437  out:
1438         spin_unlock_irq(&dev->power.lock);
1439 }
1440 EXPORT_SYMBOL_GPL(pm_runtime_forbid);
1441
1442 /**
1443  * pm_runtime_allow - Unblock runtime PM of a device.
1444  * @dev: Device to handle.
1445  *
1446  * Decrease the device's usage count and set its power.runtime_auto flag.
1447  */
1448 void pm_runtime_allow(struct device *dev)
1449 {
1450         spin_lock_irq(&dev->power.lock);
1451         if (dev->power.runtime_auto)
1452                 goto out;
1453
1454         dev->power.runtime_auto = true;
1455         if (atomic_dec_and_test(&dev->power.usage_count))
1456                 rpm_idle(dev, RPM_AUTO | RPM_ASYNC);
1457         else
1458                 trace_rpm_usage_rcuidle(dev, RPM_AUTO | RPM_ASYNC);
1459
1460  out:
1461         spin_unlock_irq(&dev->power.lock);
1462 }
1463 EXPORT_SYMBOL_GPL(pm_runtime_allow);
1464
1465 /**
1466  * pm_runtime_no_callbacks - Ignore runtime PM callbacks for a device.
1467  * @dev: Device to handle.
1468  *
1469  * Set the power.no_callbacks flag, which tells the PM core that this
1470  * device is power-managed through its parent and has no runtime PM
1471  * callbacks of its own.  The runtime sysfs attributes will be removed.
1472  */
1473 void pm_runtime_no_callbacks(struct device *dev)
1474 {
1475         spin_lock_irq(&dev->power.lock);
1476         dev->power.no_callbacks = 1;
1477         spin_unlock_irq(&dev->power.lock);
1478         if (device_is_registered(dev))
1479                 rpm_sysfs_remove(dev);
1480 }
1481 EXPORT_SYMBOL_GPL(pm_runtime_no_callbacks);
1482
1483 /**
1484  * pm_runtime_irq_safe - Leave interrupts disabled during callbacks.
1485  * @dev: Device to handle
1486  *
1487  * Set the power.irq_safe flag, which tells the PM core that the
1488  * ->runtime_suspend() and ->runtime_resume() callbacks for this device should
1489  * always be invoked with the spinlock held and interrupts disabled.  It also
1490  * causes the parent's usage counter to be permanently incremented, preventing
1491  * the parent from runtime suspending -- otherwise an irq-safe child might have
1492  * to wait for a non-irq-safe parent.
1493  */
1494 void pm_runtime_irq_safe(struct device *dev)
1495 {
1496         if (dev->parent)
1497                 pm_runtime_get_sync(dev->parent);
1498         spin_lock_irq(&dev->power.lock);
1499         dev->power.irq_safe = 1;
1500         spin_unlock_irq(&dev->power.lock);
1501 }
1502 EXPORT_SYMBOL_GPL(pm_runtime_irq_safe);
1503
1504 /**
1505  * update_autosuspend - Handle a change to a device's autosuspend settings.
1506  * @dev: Device to handle.
1507  * @old_delay: The former autosuspend_delay value.
1508  * @old_use: The former use_autosuspend value.
1509  *
1510  * Prevent runtime suspend if the new delay is negative and use_autosuspend is
1511  * set; otherwise allow it.  Send an idle notification if suspends are allowed.
1512  *
1513  * This function must be called under dev->power.lock with interrupts disabled.
1514  */
1515 static void update_autosuspend(struct device *dev, int old_delay, int old_use)
1516 {
1517         int delay = dev->power.autosuspend_delay;
1518
1519         /* Should runtime suspend be prevented now? */
1520         if (dev->power.use_autosuspend && delay < 0) {
1521
1522                 /* If it used to be allowed then prevent it. */
1523                 if (!old_use || old_delay >= 0) {
1524                         atomic_inc(&dev->power.usage_count);
1525                         rpm_resume(dev, 0);
1526                 } else {
1527                         trace_rpm_usage_rcuidle(dev, 0);
1528                 }
1529         }
1530
1531         /* Runtime suspend should be allowed now. */
1532         else {
1533
1534                 /* If it used to be prevented then allow it. */
1535                 if (old_use && old_delay < 0)
1536                         atomic_dec(&dev->power.usage_count);
1537
1538                 /* Maybe we can autosuspend now. */
1539                 rpm_idle(dev, RPM_AUTO);
1540         }
1541 }
1542
1543 /**
1544  * pm_runtime_set_autosuspend_delay - Set a device's autosuspend_delay value.
1545  * @dev: Device to handle.
1546  * @delay: Value of the new delay in milliseconds.
1547  *
1548  * Set the device's power.autosuspend_delay value.  If it changes to negative
1549  * and the power.use_autosuspend flag is set, prevent runtime suspends.  If it
1550  * changes the other way, allow runtime suspends.
1551  */
1552 void pm_runtime_set_autosuspend_delay(struct device *dev, int delay)
1553 {
1554         int old_delay, old_use;
1555
1556         spin_lock_irq(&dev->power.lock);
1557         old_delay = dev->power.autosuspend_delay;
1558         old_use = dev->power.use_autosuspend;
1559         dev->power.autosuspend_delay = delay;
1560         update_autosuspend(dev, old_delay, old_use);
1561         spin_unlock_irq(&dev->power.lock);
1562 }
1563 EXPORT_SYMBOL_GPL(pm_runtime_set_autosuspend_delay);
1564
1565 /**
1566  * __pm_runtime_use_autosuspend - Set a device's use_autosuspend flag.
1567  * @dev: Device to handle.
1568  * @use: New value for use_autosuspend.
1569  *
1570  * Set the device's power.use_autosuspend flag, and allow or prevent runtime
1571  * suspends as needed.
1572  */
1573 void __pm_runtime_use_autosuspend(struct device *dev, bool use)
1574 {
1575         int old_delay, old_use;
1576
1577         spin_lock_irq(&dev->power.lock);
1578         old_delay = dev->power.autosuspend_delay;
1579         old_use = dev->power.use_autosuspend;
1580         dev->power.use_autosuspend = use;
1581         update_autosuspend(dev, old_delay, old_use);
1582         spin_unlock_irq(&dev->power.lock);
1583 }
1584 EXPORT_SYMBOL_GPL(__pm_runtime_use_autosuspend);
1585
1586 /**
1587  * pm_runtime_init - Initialize runtime PM fields in given device object.
1588  * @dev: Device object to initialize.
1589  */
1590 void pm_runtime_init(struct device *dev)
1591 {
1592         dev->power.runtime_status = RPM_SUSPENDED;
1593         dev->power.idle_notification = false;
1594
1595         dev->power.disable_depth = 1;
1596         atomic_set(&dev->power.usage_count, 0);
1597
1598         dev->power.runtime_error = 0;
1599
1600         atomic_set(&dev->power.child_count, 0);
1601         pm_suspend_ignore_children(dev, false);
1602         dev->power.runtime_auto = true;
1603
1604         dev->power.request_pending = false;
1605         dev->power.request = RPM_REQ_NONE;
1606         dev->power.deferred_resume = false;
1607         INIT_WORK(&dev->power.work, pm_runtime_work);
1608
1609         dev->power.timer_expires = 0;
1610         hrtimer_init(&dev->power.suspend_timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
1611         dev->power.suspend_timer.function = pm_suspend_timer_fn;
1612
1613         init_waitqueue_head(&dev->power.wait_queue);
1614 }
1615
1616 /**
1617  * pm_runtime_reinit - Re-initialize runtime PM fields in given device object.
1618  * @dev: Device object to re-initialize.
1619  */
1620 void pm_runtime_reinit(struct device *dev)
1621 {
1622         if (!pm_runtime_enabled(dev)) {
1623                 if (dev->power.runtime_status == RPM_ACTIVE)
1624                         pm_runtime_set_suspended(dev);
1625                 if (dev->power.irq_safe) {
1626                         spin_lock_irq(&dev->power.lock);
1627                         dev->power.irq_safe = 0;
1628                         spin_unlock_irq(&dev->power.lock);
1629                         if (dev->parent)
1630                                 pm_runtime_put(dev->parent);
1631                 }
1632         }
1633 }
1634
1635 /**
1636  * pm_runtime_remove - Prepare for removing a device from device hierarchy.
1637  * @dev: Device object being removed from device hierarchy.
1638  */
1639 void pm_runtime_remove(struct device *dev)
1640 {
1641         __pm_runtime_disable(dev, false);
1642         pm_runtime_reinit(dev);
1643 }
1644
1645 /**
1646  * pm_runtime_clean_up_links - Prepare links to consumers for driver removal.
1647  * @dev: Device whose driver is going to be removed.
1648  *
1649  * Check links from this device to any consumers and if any of them have active
1650  * runtime PM references to the device, drop the usage counter of the device
1651  * (as many times as needed).
1652  *
1653  * Links with the DL_FLAG_MANAGED flag unset are ignored.
1654  *
1655  * Since the device is guaranteed to be runtime-active at the point this is
1656  * called, nothing else needs to be done here.
1657  *
1658  * Moreover, this is called after device_links_busy() has returned 'false', so
1659  * the status of each link is guaranteed to be DL_STATE_SUPPLIER_UNBIND and
1660  * therefore rpm_active can't be manipulated concurrently.
1661  */
1662 void pm_runtime_clean_up_links(struct device *dev)
1663 {
1664         struct device_link *link;
1665         int idx;
1666
1667         idx = device_links_read_lock();
1668
1669         list_for_each_entry_rcu(link, &dev->links.consumers, s_node,
1670                                 device_links_read_lock_held()) {
1671                 if (!(link->flags & DL_FLAG_MANAGED))
1672                         continue;
1673
1674                 while (refcount_dec_not_one(&link->rpm_active))
1675                         pm_runtime_put_noidle(dev);
1676         }
1677
1678         device_links_read_unlock(idx);
1679 }
1680
1681 /**
1682  * pm_runtime_get_suppliers - Resume and reference-count supplier devices.
1683  * @dev: Consumer device.
1684  */
1685 void pm_runtime_get_suppliers(struct device *dev)
1686 {
1687         struct device_link *link;
1688         int idx;
1689
1690         idx = device_links_read_lock();
1691
1692         list_for_each_entry_rcu(link, &dev->links.suppliers, c_node,
1693                                 device_links_read_lock_held())
1694                 if (link->flags & DL_FLAG_PM_RUNTIME) {
1695                         link->supplier_preactivated = true;
1696                         refcount_inc(&link->rpm_active);
1697                         pm_runtime_get_sync(link->supplier);
1698                 }
1699
1700         device_links_read_unlock(idx);
1701 }
1702
1703 /**
1704  * pm_runtime_put_suppliers - Drop references to supplier devices.
1705  * @dev: Consumer device.
1706  */
1707 void pm_runtime_put_suppliers(struct device *dev)
1708 {
1709         struct device_link *link;
1710         int idx;
1711
1712         idx = device_links_read_lock();
1713
1714         list_for_each_entry_rcu(link, &dev->links.suppliers, c_node,
1715                                 device_links_read_lock_held())
1716                 if (link->supplier_preactivated) {
1717                         link->supplier_preactivated = false;
1718                         if (refcount_dec_not_one(&link->rpm_active))
1719                                 pm_runtime_put(link->supplier);
1720                 }
1721
1722         device_links_read_unlock(idx);
1723 }
1724
1725 void pm_runtime_new_link(struct device *dev)
1726 {
1727         spin_lock_irq(&dev->power.lock);
1728         dev->power.links_count++;
1729         spin_unlock_irq(&dev->power.lock);
1730 }
1731
1732 void pm_runtime_drop_link(struct device *dev)
1733 {
1734         spin_lock_irq(&dev->power.lock);
1735         WARN_ON(dev->power.links_count == 0);
1736         dev->power.links_count--;
1737         spin_unlock_irq(&dev->power.lock);
1738 }
1739
1740 static bool pm_runtime_need_not_resume(struct device *dev)
1741 {
1742         return atomic_read(&dev->power.usage_count) <= 1 &&
1743                 (atomic_read(&dev->power.child_count) == 0 ||
1744                  dev->power.ignore_children);
1745 }
1746
1747 /**
1748  * pm_runtime_force_suspend - Force a device into suspend state if needed.
1749  * @dev: Device to suspend.
1750  *
1751  * Disable runtime PM so we safely can check the device's runtime PM status and
1752  * if it is active, invoke its ->runtime_suspend callback to suspend it and
1753  * change its runtime PM status field to RPM_SUSPENDED.  Also, if the device's
1754  * usage and children counters don't indicate that the device was in use before
1755  * the system-wide transition under way, decrement its parent's children counter
1756  * (if there is a parent).  Keep runtime PM disabled to preserve the state
1757  * unless we encounter errors.
1758  *
1759  * Typically this function may be invoked from a system suspend callback to make
1760  * sure the device is put into low power state and it should only be used during
1761  * system-wide PM transitions to sleep states.  It assumes that the analogous
1762  * pm_runtime_force_resume() will be used to resume the device.
1763  */
1764 int pm_runtime_force_suspend(struct device *dev)
1765 {
1766         int (*callback)(struct device *);
1767         int ret;
1768
1769         pm_runtime_disable(dev);
1770         if (pm_runtime_status_suspended(dev))
1771                 return 0;
1772
1773         callback = RPM_GET_CALLBACK(dev, runtime_suspend);
1774
1775         ret = callback ? callback(dev) : 0;
1776         if (ret)
1777                 goto err;
1778
1779         /*
1780          * If the device can stay in suspend after the system-wide transition
1781          * to the working state that will follow, drop the children counter of
1782          * its parent, but set its status to RPM_SUSPENDED anyway in case this
1783          * function will be called again for it in the meantime.
1784          */
1785         if (pm_runtime_need_not_resume(dev))
1786                 pm_runtime_set_suspended(dev);
1787         else
1788                 __update_runtime_status(dev, RPM_SUSPENDED);
1789
1790         return 0;
1791
1792 err:
1793         pm_runtime_enable(dev);
1794         return ret;
1795 }
1796 EXPORT_SYMBOL_GPL(pm_runtime_force_suspend);
1797
1798 /**
1799  * pm_runtime_force_resume - Force a device into resume state if needed.
1800  * @dev: Device to resume.
1801  *
1802  * Prior invoking this function we expect the user to have brought the device
1803  * into low power state by a call to pm_runtime_force_suspend(). Here we reverse
1804  * those actions and bring the device into full power, if it is expected to be
1805  * used on system resume.  In the other case, we defer the resume to be managed
1806  * via runtime PM.
1807  *
1808  * Typically this function may be invoked from a system resume callback.
1809  */
1810 int pm_runtime_force_resume(struct device *dev)
1811 {
1812         int (*callback)(struct device *);
1813         int ret = 0;
1814
1815         if (!pm_runtime_status_suspended(dev) || pm_runtime_need_not_resume(dev))
1816                 goto out;
1817
1818         /*
1819          * The value of the parent's children counter is correct already, so
1820          * just update the status of the device.
1821          */
1822         __update_runtime_status(dev, RPM_ACTIVE);
1823
1824         callback = RPM_GET_CALLBACK(dev, runtime_resume);
1825
1826         ret = callback ? callback(dev) : 0;
1827         if (ret) {
1828                 pm_runtime_set_suspended(dev);
1829                 goto out;
1830         }
1831
1832         pm_runtime_mark_last_busy(dev);
1833 out:
1834         pm_runtime_enable(dev);
1835         return ret;
1836 }
1837 EXPORT_SYMBOL_GPL(pm_runtime_force_resume);