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