drivers/base/power/runtime.c

   1 /*
   2  * drivers/base/power/runtime.c - Helper functions for device runtime PM
   3  *
   4  * Copyright (c) 2009 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc.
   5  * Copyright (C) 2010 Alan Stern <stern@rowland.harvard.edu>
   6  *
   7  * This file is released under the GPLv2.
   8  */
   9
  10 #include <linux/sched.h>
  11 #include <linux/export.h>
  12 #include <linux/pm_runtime.h>
  13 #include <linux/pm_wakeirq.h>
  14 #include <trace/events/rpm.h>
  15 #include "power.h"
  16
  17 typedef int (*pm_callback_t)(struct device *);
  18
  19 static pm_callback_t __rpm_get_callback(struct device *dev, size_t cb_offset)
  20 {
  21         pm_callback_t cb;
  22         const struct dev_pm_ops *ops;
  23
  24         if (dev->pm_domain)
  25                 ops = &dev->pm_domain->ops;
  26         else if (dev->type && dev->type->pm)
  27                 ops = dev->type->pm;
  28         else if (dev->class && dev->class->pm)
  29                 ops = dev->class->pm;
  30         else if (dev->bus && dev->bus->pm)
  31                 ops = dev->bus->pm;
  32         else
  33                 ops = NULL;
  34
  35         if (ops)
  36                 cb = *(pm_callback_t *)((void *)ops + cb_offset);
  37         else
  38                 cb = NULL;
  39
  40         if (!cb && dev->driver && dev->driver->pm)
  41                 cb = *(pm_callback_t *)((void *)dev->driver->pm + cb_offset);
  42
  43         return cb;
  44 }
  45
  46 #define RPM_GET_CALLBACK(dev, callback) \
  47                 __rpm_get_callback(dev, offsetof(struct dev_pm_ops, callback))
  48
  49 static int rpm_resume(struct device *dev, int rpmflags);
  50 static int rpm_suspend(struct device *dev, int rpmflags);
  51
  52 /**
  53  * update_pm_runtime_accounting - Update the time accounting of power states
  54  * @dev: Device to update the accounting for
  55  *
  56  * In order to be able to have time accounting of the various power states
  57  * (as used by programs such as PowerTOP to show the effectiveness of runtime
  58  * PM), we need to track the time spent in each state.
  59  * update_pm_runtime_accounting must be called each time before the
  60  * runtime_status field is updated, to account the time in the old state
  61  * correctly.
  62  */
  63 void update_pm_runtime_accounting(struct device *dev)
  64 {
  65         unsigned long now = jiffies;
  66         unsigned long delta;
  67
  68         delta = now - dev->power.accounting_timestamp;
  69
  70         dev->power.accounting_timestamp = now;
  71
  72         if (dev->power.disable_depth > 0)
  73                 return;
  74
  75         if (dev->power.runtime_status == RPM_SUSPENDED)
  76                 dev->power.suspended_jiffies += delta;
  77         else
  78                 dev->power.active_jiffies += delta;
  79 }
  80
  81 static void __update_runtime_status(struct device *dev, enum rpm_status status)
  82 {
  83         update_pm_runtime_accounting(dev);
  84         dev->power.runtime_status = status;
  85 }
  86
  87 /**
  88  * pm_runtime_deactivate_timer - Deactivate given device's suspend timer.
  89  * @dev: Device to handle.
  90  */
  91 static void pm_runtime_deactivate_timer(struct device *dev)
  92 {
  93         if (dev->power.timer_expires > 0) {
  94                 del_timer(&dev->power.suspend_timer);
  95                 dev->power.timer_expires = 0;
  96         }
  97 }
  98
  99 /**
 100  * pm_runtime_cancel_pending - Deactivate suspend timer and cancel requests.
 101  * @dev: Device to handle.
 102  */
 103 static void pm_runtime_cancel_pending(struct device *dev)
 104 {
 105         pm_runtime_deactivate_timer(dev);
 106         /*
 107          * In case there's a request pending, make sure its work function will
 108          * return without doing anything.
 109          */
 110         dev->power.request = RPM_REQ_NONE;
 111 }
 112
 113 /*
 114  * pm_runtime_autosuspend_expiration - Get a device's autosuspend-delay expiration time.
 115  * @dev: Device to handle.
 116  *
 117  * Compute the autosuspend-delay expiration time based on the device's
 118  * power.last_busy time.  If the delay has already expired or is disabled
 119  * (negative) or the power.use_autosuspend flag isn't set, return 0.
 120  * Otherwise return the expiration time in jiffies (adjusted to be nonzero).
 121  *
 122  * This function may be called either with or without dev->power.lock held.
 123  * Either way it can be racy, since power.last_busy may be updated at any time.
 124  */
 125 unsigned long pm_runtime_autosuspend_expiration(struct device *dev)
 126 {
 127         int autosuspend_delay;
 128         long elapsed;
 129         unsigned long last_busy;
 130         unsigned long expires = 0;
 131
 132         if (!dev->power.use_autosuspend)
 133                 goto out;
 134
 135         autosuspend_delay = ACCESS_ONCE(dev->power.autosuspend_delay);
 136         if (autosuspend_delay < 0)
 137                 goto out;
 138
 139         last_busy = ACCESS_ONCE(dev->power.last_busy);
 140         elapsed = jiffies - last_busy;
 141         if (elapsed < 0)
 142                 goto out;       /* jiffies has wrapped around. */
 143
 144         /*
 145          * If the autosuspend_delay is >= 1 second, align the timer by rounding
 146          * up to the nearest second.
 147          */
 148         expires = last_busy + msecs_to_jiffies(autosuspend_delay);
 149         if (autosuspend_delay >= 1000)
 150                 expires = round_jiffies(expires);
 151         expires += !expires;
 152         if (elapsed >= expires - last_busy)
 153                 expires = 0;    /* Already expired. */
 154
 155  out:
 156         return expires;
 157 }
 158 EXPORT_SYMBOL_GPL(pm_runtime_autosuspend_expiration);
 159
 160 static int dev_memalloc_noio(struct device *dev, void *data)
 161 {
 162         return dev->power.memalloc_noio;
 163 }
 164
 165 /*
 166  * pm_runtime_set_memalloc_noio - Set a device's memalloc_noio flag.
 167  * @dev: Device to handle.
 168  * @enable: True for setting the flag and False for clearing the flag.
 169  *
 170  * Set the flag for all devices in the path from the device to the
 171  * root device in the device tree if @enable is true, otherwise clear
 172  * the flag for devices in the path whose siblings don't set the flag.
 173  *
 174  * The function should only be called by block device, or network
 175  * device driver for solving the deadlock problem during runtime
 176  * resume/suspend:
 177  *
 178  *     If memory allocation with GFP_KERNEL is called inside runtime
 179  *     resume/suspend callback of any one of its ancestors(or the
 180  *     block device itself), the deadlock may be triggered inside the
 181  *     memory allocation since it might not complete until the block
 182  *     device becomes active and the involed page I/O finishes. The
 183  *     situation is pointed out first by Alan Stern. Network device
 184  *     are involved in iSCSI kind of situation.
 185  *
 186  * The lock of dev_hotplug_mutex is held in the function for handling
 187  * hotplug race because pm_runtime_set_memalloc_noio() may be called
 188  * in async probe().
 189  *
 190  * The function should be called between device_add() and device_del()
 191  * on the affected device(block/network device).
 192  */
 193 void pm_runtime_set_memalloc_noio(struct device *dev, bool enable)
 194 {
 195         static DEFINE_MUTEX(dev_hotplug_mutex);
 196
 197         mutex_lock(&dev_hotplug_mutex);
 198         for (;;) {
 199                 bool enabled;
 200
 201                 /* hold power lock since bitfield is not SMP-safe. */
 202                 spin_lock_irq(&dev->power.lock);
 203                 enabled = dev->power.memalloc_noio;
 204                 dev->power.memalloc_noio = enable;
 205                 spin_unlock_irq(&dev->power.lock);
 206
 207                 /*
 208                  * not need to enable ancestors any more if the device
 209                  * has been enabled.
 210                  */
 211                 if (enabled && enable)
 212                         break;
 213
 214                 dev = dev->parent;
 215
 216                 /*
 217                  * clear flag of the parent device only if all the
 218                  * children don't set the flag because ancestor's
 219                  * flag was set by any one of the descendants.
 220                  */
 221                 if (!dev || (!enable &&
 222                              device_for_each_child(dev, NULL,
 223                                                    dev_memalloc_noio)))
 224                         break;
 225         }
 226         mutex_unlock(&dev_hotplug_mutex);
 227 }
 228 EXPORT_SYMBOL_GPL(pm_runtime_set_memalloc_noio);
 229
 230 /**
 231  * rpm_check_suspend_allowed - Test whether a device may be suspended.
 232  * @dev: Device to test.
 233  */
 234 static int rpm_check_suspend_allowed(struct device *dev)
 235 {
 236         int retval = 0;
 237
 238         if (dev->power.runtime_error)
 239                 retval = -EINVAL;
 240         else if (dev->power.disable_depth > 0)
 241                 retval = -EACCES;
 242         else if (atomic_read(&dev->power.usage_count) > 0)
 243                 retval = -EAGAIN;
 244         else if (!dev->power.ignore_children &&
 245                         atomic_read(&dev->power.child_count))
 246                 retval = -EBUSY;
 247
 248         /* Pending resume requests take precedence over suspends. */
 249         else if ((dev->power.deferred_resume
 250                         && dev->power.runtime_status == RPM_SUSPENDING)
 251             || (dev->power.request_pending
 252                         && dev->power.request == RPM_REQ_RESUME))
 253                 retval = -EAGAIN;
 254         else if (__dev_pm_qos_read_value(dev) < 0)
 255                 retval = -EPERM;
 256         else if (dev->power.runtime_status == RPM_SUSPENDED)
 257                 retval = 1;
 258
 259         return retval;
 260 }
 261
 262 /**
 263  * __rpm_callback - Run a given runtime PM callback for a given device.
 264  * @cb: Runtime PM callback to run.
 265  * @dev: Device to run the callback for.
 266  */
 267 static int __rpm_callback(int (*cb)(struct device *), struct device *dev)
 268         __releases(&dev->power.lock) __acquires(&dev->power.lock)
 269 {
 270         int retval;
 271
 272         if (dev->power.irq_safe)
 273                 spin_unlock(&dev->power.lock);
 274         else
 275                 spin_unlock_irq(&dev->power.lock);
 276
 277         retval = cb(dev);
 278
 279         if (dev->power.irq_safe)
 280                 spin_lock(&dev->power.lock);
 281         else
 282                 spin_lock_irq(&dev->power.lock);
 283
 284         return retval;
 285 }
 286
 287 /**
 288  * rpm_idle - Notify device bus type if the device can be suspended.
 289  * @dev: Device to notify the bus type about.
 290  * @rpmflags: Flag bits.
 291  *
 292  * Check if the device's runtime PM status allows it to be suspended.  If
 293  * another idle notification has been started earlier, return immediately.  If
 294  * the RPM_ASYNC flag is set then queue an idle-notification request; otherwise
 295  * run the ->runtime_idle() callback directly. If the ->runtime_idle callback
 296  * doesn't exist or if it returns 0, call rpm_suspend with the RPM_AUTO flag.
 297  *
 298  * This function must be called under dev->power.lock with interrupts disabled.
 299  */
 300 static int rpm_idle(struct device *dev, int rpmflags)
 301 {
 302         int (*callback)(struct device *);
 303         int retval;
 304
 305         trace_rpm_idle_rcuidle(dev, rpmflags);
 306         retval = rpm_check_suspend_allowed(dev);
 307         if (retval < 0)
 308                 ;       /* Conditions are wrong. */
 309
 310         /* Idle notifications are allowed only in the RPM_ACTIVE state. */
 311         else if (dev->power.runtime_status != RPM_ACTIVE)
 312                 retval = -EAGAIN;
 313
 314         /*
 315          * Any pending request other than an idle notification takes
 316          * precedence over us, except that the timer may be running.
 317          */
 318         else if (dev->power.request_pending &&
 319             dev->power.request > RPM_REQ_IDLE)
 320                 retval = -EAGAIN;
 321
 322         /* Act as though RPM_NOWAIT is always set. */
 323         else if (dev->power.idle_notification)
 324                 retval = -EINPROGRESS;
 325         if (retval)
 326                 goto out;
 327
 328         /* Pending requests need to be canceled. */
 329         dev->power.request = RPM_REQ_NONE;
 330
 331         if (dev->power.no_callbacks)
 332                 goto out;
 333
 334         /* Carry out an asynchronous or a synchronous idle notification. */
 335         if (rpmflags & RPM_ASYNC) {
 336                 dev->power.request = RPM_REQ_IDLE;
 337                 if (!dev->power.request_pending) {
 338                         dev->power.request_pending = true;
 339                         queue_work(pm_wq, &dev->power.work);
 340                 }
 341                 trace_rpm_return_int_rcuidle(dev, _THIS_IP_, 0);
 342                 return 0;
 343         }
 344
 345         dev->power.idle_notification = true;
 346
 347         callback = RPM_GET_CALLBACK(dev, runtime_idle);
 348
 349         if (callback)
 350                 retval = __rpm_callback(callback, dev);
 351
 352         dev->power.idle_notification = false;
 353         wake_up_all(&dev->power.wait_queue);
 354
 355  out:
 356         trace_rpm_return_int_rcuidle(dev, _THIS_IP_, retval);
 357         return retval ? retval : rpm_suspend(dev, rpmflags | RPM_AUTO);
 358 }
 359
 360 /**
 361  * rpm_callback - Run a given runtime PM callback for a given device.
 362  * @cb: Runtime PM callback to run.
 363  * @dev: Device to run the callback for.
 364  */
 365 static int rpm_callback(int (*cb)(struct device *), struct device *dev)
 366 {
 367         int retval;
 368
 369         if (!cb)
 370                 return -ENOSYS;
 371
 372         if (dev->power.memalloc_noio) {
 373                 unsigned int noio_flag;
 374
 375                 /*
 376                  * Deadlock might be caused if memory allocation with
 377                  * GFP_KERNEL happens inside runtime_suspend and
 378                  * runtime_resume callbacks of one block device's
 379                  * ancestor or the block device itself. Network
 380                  * device might be thought as part of iSCSI block
 381                  * device, so network device and its ancestor should
 382                  * be marked as memalloc_noio too.
 383                  */
 384                 noio_flag = memalloc_noio_save();
 385                 retval = __rpm_callback(cb, dev);
 386                 memalloc_noio_restore(noio_flag);
 387         } else {
 388                 retval = __rpm_callback(cb, dev);
 389         }
 390
 391         dev->power.runtime_error = retval;
 392         return retval != -EACCES ? retval : -EIO;
 393 }
 394
 395 /**
 396  * rpm_suspend - Carry out runtime suspend of given device.
 397  * @dev: Device to suspend.
 398  * @rpmflags: Flag bits.
 399  *
 400  * Check if the device's runtime PM status allows it to be suspended.
 401  * Cancel a pending idle notification, autosuspend or suspend. If
 402  * another suspend has been started earlier, either return immediately
 403  * or wait for it to finish, depending on the RPM_NOWAIT and RPM_ASYNC
 404  * flags. If the RPM_ASYNC flag is set then queue a suspend request;
 405  * otherwise run the ->runtime_suspend() callback directly. When
 406  * ->runtime_suspend succeeded, if a deferred resume was requested while
 407  * the callback was running then carry it out, otherwise send an idle
 408  * notification for its parent (if the suspend succeeded and both
 409  * ignore_children of parent->power and irq_safe of dev->power are not set).
 410  * If ->runtime_suspend failed with -EAGAIN or -EBUSY, and if the RPM_AUTO
 411  * flag is set and the next autosuspend-delay expiration time is in the
 412  * future, schedule another autosuspend attempt.
 413  *
 414  * This function must be called under dev->power.lock with interrupts disabled.
 415  */
 416 static int rpm_suspend(struct device *dev, int rpmflags)
 417         __releases(&dev->power.lock) __acquires(&dev->power.lock)
 418 {
 419         int (*callback)(struct device *);
 420         struct device *parent = NULL;
 421         int retval;
 422
 423         trace_rpm_suspend_rcuidle(dev, rpmflags);
 424
 425  repeat:
 426         retval = rpm_check_suspend_allowed(dev);
 427
 428         if (retval < 0)
 429                 ;       /* Conditions are wrong. */
 430
 431         /* Synchronous suspends are not allowed in the RPM_RESUMING state. */
 432         else if (dev->power.runtime_status == RPM_RESUMING &&
 433             !(rpmflags & RPM_ASYNC))
 434                 retval = -EAGAIN;
 435         if (retval)
 436                 goto out;
 437
 438         /* If the autosuspend_delay time hasn't expired yet, reschedule. */
 439         if ((rpmflags & RPM_AUTO)
 440             && dev->power.runtime_status != RPM_SUSPENDING) {
 441                 unsigned long expires = pm_runtime_autosuspend_expiration(dev);
 442
 443                 if (expires != 0) {
 444                         /* Pending requests need to be canceled. */
 445                         dev->power.request = RPM_REQ_NONE;
 446
 447                         /*
 448                          * Optimization: If the timer is already running and is
 449                          * set to expire at or before the autosuspend delay,
 450                          * avoid the overhead of resetting it.  Just let it
 451                          * expire; pm_suspend_timer_fn() will take care of the
 452                          * rest.
 453                          */
 454                         if (!(dev->power.timer_expires && time_before_eq(
 455                             dev->power.timer_expires, expires))) {
 456                                 dev->power.timer_expires = expires;
 457                                 mod_timer(&dev->power.suspend_timer, expires);
 458                         }
 459                         dev->power.timer_autosuspends = 1;
 460                         goto out;
 461                 }
 462         }
 463
 464         /* Other scheduled or pending requests need to be canceled. */
 465         pm_runtime_cancel_pending(dev);
 466
 467         if (dev->power.runtime_status == RPM_SUSPENDING) {
 468                 DEFINE_WAIT(wait);
 469
 470                 if (rpmflags & (RPM_ASYNC | RPM_NOWAIT)) {
 471                         retval = -EINPROGRESS;
 472                         goto out;
 473                 }
 474
 475                 if (dev->power.irq_safe) {
 476                         spin_unlock(&dev->power.lock);
 477
 478                         cpu_relax();
 479
 480                         spin_lock(&dev->power.lock);
 481                         goto repeat;
 482                 }
 483
 484                 /* Wait for the other suspend running in parallel with us. */
 485                 for (;;) {
 486                         prepare_to_wait(&dev->power.wait_queue, &wait,
 487                                         TASK_UNINTERRUPTIBLE);
 488                         if (dev->power.runtime_status != RPM_SUSPENDING)
 489                                 break;
 490
 491                         spin_unlock_irq(&dev->power.lock);
 492
 493                         schedule();
 494
 495                         spin_lock_irq(&dev->power.lock);
 496                 }
 497                 finish_wait(&dev->power.wait_queue, &wait);
 498                 goto repeat;
 499         }
 500
 501         if (dev->power.no_callbacks)
 502                 goto no_callback;       /* Assume success. */
 503
 504         /* Carry out an asynchronous or a synchronous suspend. */
 505         if (rpmflags & RPM_ASYNC) {
 506                 dev->power.request = (rpmflags & RPM_AUTO) ?
 507                     RPM_REQ_AUTOSUSPEND : RPM_REQ_SUSPEND;
 508                 if (!dev->power.request_pending) {
 509                         dev->power.request_pending = true;
 510                         queue_work(pm_wq, &dev->power.work);
 511                 }
 512                 goto out;
 513         }
 514
 515         __update_runtime_status(dev, RPM_SUSPENDING);
 516
 517         callback = RPM_GET_CALLBACK(dev, runtime_suspend);
 518
 519         dev_pm_enable_wake_irq(dev);
 520         retval = rpm_callback(callback, dev);
 521         if (retval)
 522                 goto fail;
 523
 524  no_callback:
 525         __update_runtime_status(dev, RPM_SUSPENDED);
 526         pm_runtime_deactivate_timer(dev);
 527
 528         if (dev->parent) {
 529                 parent = dev->parent;
 530                 atomic_add_unless(&parent->power.child_count, -1, 0);
 531         }
 532         wake_up_all(&dev->power.wait_queue);
 533
 534         if (dev->power.deferred_resume) {
 535                 dev->power.deferred_resume = false;
 536                 rpm_resume(dev, 0);
 537                 retval = -EAGAIN;
 538                 goto out;
 539         }
 540
 541         /* Maybe the parent is now able to suspend. */
 542         if (parent && !parent->power.ignore_children && !dev->power.irq_safe) {
 543                 spin_unlock(&dev->power.lock);
 544
 545                 spin_lock(&parent->power.lock);
 546                 rpm_idle(parent, RPM_ASYNC);
 547                 spin_unlock(&parent->power.lock);
 548
 549                 spin_lock(&dev->power.lock);
 550         }
 551
 552  out:
 553         trace_rpm_return_int_rcuidle(dev, _THIS_IP_, retval);
 554
 555         return retval;
 556
 557  fail:
 558         dev_pm_disable_wake_irq(dev);
 559         __update_runtime_status(dev, RPM_ACTIVE);
 560         dev->power.deferred_resume = false;
 561         wake_up_all(&dev->power.wait_queue);
 562
 563         if (retval == -EAGAIN || retval == -EBUSY) {
 564                 dev->power.runtime_error = 0;
 565
 566                 /*
 567                  * If the callback routine failed an autosuspend, and
 568                  * if the last_busy time has been updated so that there
 569                  * is a new autosuspend expiration time, automatically
 570                  * reschedule another autosuspend.
 571                  */
 572                 if ((rpmflags & RPM_AUTO) &&
 573                     pm_runtime_autosuspend_expiration(dev) != 0)
 574                         goto repeat;
 575         } else {
 576                 pm_runtime_cancel_pending(dev);
 577         }
 578         goto out;
 579 }
 580
 581 /**
 582  * rpm_resume - Carry out runtime resume of given device.
 583  * @dev: Device to resume.
 584  * @rpmflags: Flag bits.
 585  *
 586  * Check if the device's runtime PM status allows it to be resumed.  Cancel
 587  * any scheduled or pending requests.  If another resume has been started
 588  * earlier, either return immediately or wait for it to finish, depending on the
 589  * RPM_NOWAIT and RPM_ASYNC flags.  Similarly, if there's a suspend running in
 590  * parallel with this function, either tell the other process to resume after
 591  * suspending (deferred_resume) or wait for it to finish.  If the RPM_ASYNC
 592  * flag is set then queue a resume request; otherwise run the
 593  * ->runtime_resume() callback directly.  Queue an idle notification for the
 594  * device if the resume succeeded.
 595  *
 596  * This function must be called under dev->power.lock with interrupts disabled.
 597  */
 598 static int rpm_resume(struct device *dev, int rpmflags)
 599         __releases(&dev->power.lock) __acquires(&dev->power.lock)
 600 {
 601         int (*callback)(struct device *);
 602         struct device *parent = NULL;
 603         int retval = 0;
 604
 605         trace_rpm_resume_rcuidle(dev, rpmflags);
 606
 607  repeat:
 608         if (dev->power.runtime_error)
 609                 retval = -EINVAL;
 610         else if (dev->power.disable_depth == 1 && dev->power.is_suspended
 611             && dev->power.runtime_status == RPM_ACTIVE)
 612                 retval = 1;
 613         else if (dev->power.disable_depth > 0)
 614                 retval = -EACCES;
 615         if (retval)
 616                 goto out;
 617
 618         /*
 619          * Other scheduled or pending requests need to be canceled.  Small
 620          * optimization: If an autosuspend timer is running, leave it running
 621          * rather than cancelling it now only to restart it again in the near
 622          * future.
 623          */
 624         dev->power.request = RPM_REQ_NONE;
 625         if (!dev->power.timer_autosuspends)
 626                 pm_runtime_deactivate_timer(dev);
 627
 628         if (dev->power.runtime_status == RPM_ACTIVE) {
 629                 retval = 1;
 630                 goto out;
 631         }
 632
 633         if (dev->power.runtime_status == RPM_RESUMING
 634             || dev->power.runtime_status == RPM_SUSPENDING) {
 635                 DEFINE_WAIT(wait);
 636
 637                 if (rpmflags & (RPM_ASYNC | RPM_NOWAIT)) {
 638                         if (dev->power.runtime_status == RPM_SUSPENDING)
 639                                 dev->power.deferred_resume = true;
 640                         else
 641                                 retval = -EINPROGRESS;
 642                         goto out;
 643                 }
 644
 645                 if (dev->power.irq_safe) {
 646                         spin_unlock(&dev->power.lock);
 647
 648                         cpu_relax();
 649
 650                         spin_lock(&dev->power.lock);
 651                         goto repeat;
 652                 }
 653
 654                 /* Wait for the operation carried out in parallel with us. */
 655                 for (;;) {
 656                         prepare_to_wait(&dev->power.wait_queue, &wait,
 657                                         TASK_UNINTERRUPTIBLE);
 658                         if (dev->power.runtime_status != RPM_RESUMING
 659                             && dev->power.runtime_status != RPM_SUSPENDING)
 660                                 break;
 661
 662                         spin_unlock_irq(&dev->power.lock);
 663
 664                         schedule();
 665
 666                         spin_lock_irq(&dev->power.lock);
 667                 }
 668                 finish_wait(&dev->power.wait_queue, &wait);
 669                 goto repeat;
 670         }
 671
 672         /*
 673          * See if we can skip waking up the parent.  This is safe only if
 674          * power.no_callbacks is set, because otherwise we don't know whether
 675          * the resume will actually succeed.
 676          */
 677         if (dev->power.no_callbacks && !parent && dev->parent) {
 678                 spin_lock_nested(&dev->parent->power.lock, SINGLE_DEPTH_NESTING);
 679                 if (dev->parent->power.disable_depth > 0
 680                     || dev->parent->power.ignore_children
 681                     || dev->parent->power.runtime_status == RPM_ACTIVE) {
 682                         atomic_inc(&dev->parent->power.child_count);
 683                         spin_unlock(&dev->parent->power.lock);
 684                         retval = 1;
 685                         goto no_callback;       /* Assume success. */
 686                 }
 687                 spin_unlock(&dev->parent->power.lock);
 688         }
 689
 690         /* Carry out an asynchronous or a synchronous resume. */
 691         if (rpmflags & RPM_ASYNC) {
 692                 dev->power.request = RPM_REQ_RESUME;
 693                 if (!dev->power.request_pending) {
 694                         dev->power.request_pending = true;
 695                         queue_work(pm_wq, &dev->power.work);
 696                 }
 697                 retval = 0;
 698                 goto out;
 699         }
 700
 701         if (!parent && dev->parent) {
 702                 /*
 703                  * Increment the parent's usage counter and resume it if
 704                  * necessary.  Not needed if dev is irq-safe; then the
 705                  * parent is permanently resumed.
 706                  */
 707                 parent = dev->parent;
 708                 if (dev->power.irq_safe)
 709                         goto skip_parent;
 710                 spin_unlock(&dev->power.lock);
 711
 712                 pm_runtime_get_noresume(parent);
 713
 714                 spin_lock(&parent->power.lock);
 715                 /*
 716                  * Resume the parent if it has runtime PM enabled and not been
 717                  * set to ignore its children.
 718                  */
 719                 if (!parent->power.disable_depth
 720                     && !parent->power.ignore_children) {
 721                         rpm_resume(parent, 0);
 722                         if (parent->power.runtime_status != RPM_ACTIVE)
 723                                 retval = -EBUSY;
 724                 }
 725                 spin_unlock(&parent->power.lock);
 726
 727                 spin_lock(&dev->power.lock);
 728                 if (retval)
 729                         goto out;
 730                 goto repeat;
 731         }
 732  skip_parent:
 733
 734         if (dev->power.no_callbacks)
 735                 goto no_callback;       /* Assume success. */
 736
 737         __update_runtime_status(dev, RPM_RESUMING);
 738
 739         callback = RPM_GET_CALLBACK(dev, runtime_resume);
 740
 741         dev_pm_disable_wake_irq(dev);
 742         retval = rpm_callback(callback, dev);
 743         if (retval) {
 744                 __update_runtime_status(dev, RPM_SUSPENDED);
 745                 pm_runtime_cancel_pending(dev);
 746                 dev_pm_enable_wake_irq(dev);
 747         } else {
 748  no_callback:
 749                 __update_runtime_status(dev, RPM_ACTIVE);
 750                 pm_runtime_mark_last_busy(dev);
 751                 if (parent)
 752                         atomic_inc(&parent->power.child_count);
 753         }
 754         wake_up_all(&dev->power.wait_queue);
 755
 756         if (retval >= 0)
 757                 rpm_idle(dev, RPM_ASYNC);
 758
 759  out:
 760         if (parent && !dev->power.irq_safe) {
 761                 spin_unlock_irq(&dev->power.lock);
 762
 763                 pm_runtime_put(parent);
 764
 765                 spin_lock_irq(&dev->power.lock);
 766         }
 767
 768         trace_rpm_return_int_rcuidle(dev, _THIS_IP_, retval);
 769
 770         return retval;
 771 }
 772
 773 /**
 774  * pm_runtime_work - Universal runtime PM work function.
 775  * @work: Work structure used for scheduling the execution of this function.
 776  *
 777  * Use @work to get the device object the work is to be done for, determine what
 778  * is to be done and execute the appropriate runtime PM function.
 779  */
 780 static void pm_runtime_work(struct work_struct *work)
 781 {
 782         struct device *dev = container_of(work, struct device, power.work);
 783         enum rpm_request req;
 784
 785         spin_lock_irq(&dev->power.lock);
 786
 787         if (!dev->power.request_pending)
 788                 goto out;
 789
 790         req = dev->power.request;
 791         dev->power.request = RPM_REQ_NONE;
 792         dev->power.request_pending = false;
 793
 794         switch (req) {
 795         case RPM_REQ_NONE:
 796                 break;
 797         case RPM_REQ_IDLE:
 798                 rpm_idle(dev, RPM_NOWAIT);
 799                 break;
 800         case RPM_REQ_SUSPEND:
 801                 rpm_suspend(dev, RPM_NOWAIT);
 802                 break;
 803         case RPM_REQ_AUTOSUSPEND:
 804                 rpm_suspend(dev, RPM_NOWAIT | RPM_AUTO);
 805                 break;
 806         case RPM_REQ_RESUME:
 807                 rpm_resume(dev, RPM_NOWAIT);
 808                 break;
 809         }
 810
 811  out:
 812         spin_unlock_irq(&dev->power.lock);
 813 }
 814
 815 /**
 816  * pm_suspend_timer_fn - Timer function for pm_schedule_suspend().
 817  * @data: Device pointer passed by pm_schedule_suspend().
 818  *
 819  * Check if the time is right and queue a suspend request.
 820  */
 821 static void pm_suspend_timer_fn(unsigned long data)
 822 {
 823         struct device *dev = (struct device *)data;
 824         unsigned long flags;
 825         unsigned long expires;
 826
 827         spin_lock_irqsave(&dev->power.lock, flags);
 828
 829         expires = dev->power.timer_expires;
 830         /* If 'expire' is after 'jiffies' we've been called too early. */
 831         if (expires > 0 && !time_after(expires, jiffies)) {
 832                 dev->power.timer_expires = 0;
 833                 rpm_suspend(dev, dev->power.timer_autosuspends ?
 834                     (RPM_ASYNC | RPM_AUTO) : RPM_ASYNC);
 835         }
 836
 837         spin_unlock_irqrestore(&dev->power.lock, flags);
 838 }
 839
 840 /**
 841  * pm_schedule_suspend - Set up a timer to submit a suspend request in future.
 842  * @dev: Device to suspend.
 843  * @delay: Time to wait before submitting a suspend request, in milliseconds.
 844  */
 845 int pm_schedule_suspend(struct device *dev, unsigned int delay)
 846 {
 847         unsigned long flags;
 848         int retval;
 849
 850         spin_lock_irqsave(&dev->power.lock, flags);
 851
 852         if (!delay) {
 853                 retval = rpm_suspend(dev, RPM_ASYNC);
 854                 goto out;
 855         }
 856
 857         retval = rpm_check_suspend_allowed(dev);
 858         if (retval)
 859                 goto out;
 860
 861         /* Other scheduled or pending requests need to be canceled. */
 862         pm_runtime_cancel_pending(dev);
 863
 864         dev->power.timer_expires = jiffies + msecs_to_jiffies(delay);
 865         dev->power.timer_expires += !dev->power.timer_expires;
 866         dev->power.timer_autosuspends = 0;
 867         mod_timer(&dev->power.suspend_timer, dev->power.timer_expires);
 868
 869  out:
 870         spin_unlock_irqrestore(&dev->power.lock, flags);
 871
 872         return retval;
 873 }
 874 EXPORT_SYMBOL_GPL(pm_schedule_suspend);
 875
 876 /**
 877  * __pm_runtime_idle - Entry point for runtime idle operations.
 878  * @dev: Device to send idle notification for.
 879  * @rpmflags: Flag bits.
 880  *
 881  * If the RPM_GET_PUT flag is set, decrement the device's usage count and
 882  * return immediately if it is larger than zero.  Then carry out an idle
 883  * notification, either synchronous or asynchronous.
 884  *
 885  * This routine may be called in atomic context if the RPM_ASYNC flag is set,
 886  * or if pm_runtime_irq_safe() has been called.
 887  */
 888 int __pm_runtime_idle(struct device *dev, int rpmflags)
 889 {
 890         unsigned long flags;
 891         int retval;
 892
 893         might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe);
 894
 895         if (rpmflags & RPM_GET_PUT) {
 896                 if (!atomic_dec_and_test(&dev->power.usage_count))
 897                         return 0;
 898         }
 899
 900         spin_lock_irqsave(&dev->power.lock, flags);
 901         retval = rpm_idle(dev, rpmflags);
 902         spin_unlock_irqrestore(&dev->power.lock, flags);
 903
 904         return retval;
 905 }
 906 EXPORT_SYMBOL_GPL(__pm_runtime_idle);
 907
 908 /**
 909  * __pm_runtime_suspend - Entry point for runtime put/suspend operations.
 910  * @dev: Device to suspend.
 911  * @rpmflags: Flag bits.
 912  *
 913  * If the RPM_GET_PUT flag is set, decrement the device's usage count and
 914  * return immediately if it is larger than zero.  Then carry out a suspend,
 915  * either synchronous or asynchronous.
 916  *
 917  * This routine may be called in atomic context if the RPM_ASYNC flag is set,
 918  * or if pm_runtime_irq_safe() has been called.
 919  */
 920 int __pm_runtime_suspend(struct device *dev, int rpmflags)
 921 {
 922         unsigned long flags;
 923         int retval;
 924
 925         might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe);
 926
 927         if (rpmflags & RPM_GET_PUT) {
 928                 if (!atomic_dec_and_test(&dev->power.usage_count))
 929                         return 0;
 930         }
 931
 932         spin_lock_irqsave(&dev->power.lock, flags);
 933         retval = rpm_suspend(dev, rpmflags);
 934         spin_unlock_irqrestore(&dev->power.lock, flags);
 935
 936         return retval;
 937 }
 938 EXPORT_SYMBOL_GPL(__pm_runtime_suspend);
 939
 940 /**
 941  * __pm_runtime_resume - Entry point for runtime resume operations.
 942  * @dev: Device to resume.
 943  * @rpmflags: Flag bits.
 944  *
 945  * If the RPM_GET_PUT flag is set, increment the device's usage count.  Then
 946  * carry out a resume, either synchronous or asynchronous.
 947  *
 948  * This routine may be called in atomic context if the RPM_ASYNC flag is set,
 949  * or if pm_runtime_irq_safe() has been called.
 950  */
 951 int __pm_runtime_resume(struct device *dev, int rpmflags)
 952 {
 953         unsigned long flags;
 954         int retval;
 955
 956         might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe);
 957
 958         if (rpmflags & RPM_GET_PUT)
 959                 atomic_inc(&dev->power.usage_count);
 960
 961         spin_lock_irqsave(&dev->power.lock, flags);
 962         retval = rpm_resume(dev, rpmflags);
 963         spin_unlock_irqrestore(&dev->power.lock, flags);
 964
 965         return retval;
 966 }
 967 EXPORT_SYMBOL_GPL(__pm_runtime_resume);
 968
 969 /**
 970  * pm_runtime_get_if_in_use - Conditionally bump up the device's usage counter.
 971  * @dev: Device to handle.
 972  *
 973  * Return -EINVAL if runtime PM is disabled for the device.
 974  *
 975  * If that's not the case and if the device's runtime PM status is RPM_ACTIVE
 976  * and the runtime PM usage counter is nonzero, increment the counter and
 977  * return 1.  Otherwise return 0 without changing the counter.
 978  */
 979 int pm_runtime_get_if_in_use(struct device *dev)
 980 {
 981         unsigned long flags;
 982         int retval;
 983
 984         spin_lock_irqsave(&dev->power.lock, flags);
 985         retval = dev->power.disable_depth > 0 ? -EINVAL :
 986                 dev->power.runtime_status == RPM_ACTIVE
 987                         && atomic_inc_not_zero(&dev->power.usage_count);
 988         spin_unlock_irqrestore(&dev->power.lock, flags);
 989         return retval;
 990 }
 991 EXPORT_SYMBOL_GPL(pm_runtime_get_if_in_use);
 992
 993 /**
 994  * __pm_runtime_set_status - Set runtime PM status of a device.
 995  * @dev: Device to handle.
 996  * @status: New runtime PM status of the device.
 997  *
 998  * If runtime PM of the device is disabled or its power.runtime_error field is
 999  * different from zero, the status may be changed either to RPM_ACTIVE, or to
1000  * RPM_SUSPENDED, as long as that reflects the actual state of the device.
1001  * However, if the device has a parent and the parent is not active, and the
1002  * parent's power.ignore_children flag is unset, the device's status cannot be
1003  * set to RPM_ACTIVE, so -EBUSY is returned in that case.
1004  *
1005  * If successful, __pm_runtime_set_status() clears the power.runtime_error field
1006  * and the device parent's counter of unsuspended children is modified to
1007  * reflect the new status.  If the new status is RPM_SUSPENDED, an idle
1008  * notification request for the parent is submitted.
1009  */
1010 int __pm_runtime_set_status(struct device *dev, unsigned int status)
1011 {
1012         struct device *parent = dev->parent;
1013         unsigned long flags;
1014         bool notify_parent = false;
1015         int error = 0;
1016
1017         if (status != RPM_ACTIVE && status != RPM_SUSPENDED)
1018                 return -EINVAL;
1019
1020         spin_lock_irqsave(&dev->power.lock, flags);
1021
1022         if (!dev->power.runtime_error && !dev->power.disable_depth) {
1023                 error = -EAGAIN;
1024                 goto out;
1025         }
1026
1027         if (dev->power.runtime_status == status)
1028                 goto out_set;
1029
1030         if (status == RPM_SUSPENDED) {
1031                 /*
1032                  * It is invalid to suspend a device with an active child,
1033                  * unless it has been set to ignore its children.
1034                  */
1035                 if (!dev->power.ignore_children &&
1036                         atomic_read(&dev->power.child_count)) {
1037                         dev_err(dev, "runtime PM trying to suspend device but active child\n");
1038                         error = -EBUSY;
1039                         goto out;
1040                 }
1041
1042                 if (parent) {
1043                         atomic_add_unless(&parent->power.child_count, -1, 0);
1044                         notify_parent = !parent->power.ignore_children;
1045                 }
1046                 goto out_set;
1047         }
1048
1049         if (parent) {
1050                 spin_lock_nested(&parent->power.lock, SINGLE_DEPTH_NESTING);
1051
1052                 /*
1053                  * It is invalid to put an active child under a parent that is
1054                  * not active, has runtime PM enabled and the
1055                  * 'power.ignore_children' flag unset.
1056                  */
1057                 if (!parent->power.disable_depth
1058                     && !parent->power.ignore_children
1059                     && parent->power.runtime_status != RPM_ACTIVE) {
1060                         dev_err(dev, "runtime PM trying to activate child device %s but parent (%s) is not active\n",
1061                                 dev_name(dev),
1062                                 dev_name(parent));
1063                         error = -EBUSY;
1064                 } else if (dev->power.runtime_status == RPM_SUSPENDED) {
1065                         atomic_inc(&parent->power.child_count);
1066                 }
1067
1068                 spin_unlock(&parent->power.lock);
1069
1070                 if (error)
1071                         goto out;
1072         }
1073
1074  out_set:
1075         __update_runtime_status(dev, status);
1076         dev->power.runtime_error = 0;
1077  out:
1078         spin_unlock_irqrestore(&dev->power.lock, flags);
1079
1080         if (notify_parent)
1081                 pm_request_idle(parent);
1082
1083         return error;
1084 }
1085 EXPORT_SYMBOL_GPL(__pm_runtime_set_status);
1086
1087 /**
1088  * __pm_runtime_barrier - Cancel pending requests and wait for completions.
1089  * @dev: Device to handle.
1090  *
1091  * Flush all pending requests for the device from pm_wq and wait for all
1092  * runtime PM operations involving the device in progress to complete.
1093  *
1094  * Should be called under dev->power.lock with interrupts disabled.
1095  */
1096 static void __pm_runtime_barrier(struct device *dev)
1097 {
1098         pm_runtime_deactivate_timer(dev);
1099
1100         if (dev->power.request_pending) {
1101                 dev->power.request = RPM_REQ_NONE;
1102                 spin_unlock_irq(&dev->power.lock);
1103
1104                 cancel_work_sync(&dev->power.work);
1105
1106                 spin_lock_irq(&dev->power.lock);
1107                 dev->power.request_pending = false;
1108         }
1109
1110         if (dev->power.runtime_status == RPM_SUSPENDING
1111             || dev->power.runtime_status == RPM_RESUMING
1112             || dev->power.idle_notification) {
1113                 DEFINE_WAIT(wait);
1114
1115                 /* Suspend, wake-up or idle notification in progress. */
1116                 for (;;) {
1117                         prepare_to_wait(&dev->power.wait_queue, &wait,
1118                                         TASK_UNINTERRUPTIBLE);
1119                         if (dev->power.runtime_status != RPM_SUSPENDING
1120                             && dev->power.runtime_status != RPM_RESUMING
1121                             && !dev->power.idle_notification)
1122                                 break;
1123                         spin_unlock_irq(&dev->power.lock);
1124
1125                         schedule();
1126
1127                         spin_lock_irq(&dev->power.lock);
1128                 }
1129                 finish_wait(&dev->power.wait_queue, &wait);
1130         }
1131 }
1132
1133 /**
1134  * pm_runtime_barrier - Flush pending requests and wait for completions.
1135  * @dev: Device to handle.
1136  *
1137  * Prevent the device from being suspended by incrementing its usage counter and
1138  * if there's a pending resume request for the device, wake the device up.
1139  * Next, make sure that all pending requests for the device have been flushed
1140  * from pm_wq and wait for all runtime PM operations involving the device in
1141  * progress to complete.
1142  *
1143  * Return value:
1144  * 1, if there was a resume request pending and the device had to be woken up,
1145  * 0, otherwise
1146  */
1147 int pm_runtime_barrier(struct device *dev)
1148 {
1149         int retval = 0;
1150
1151         pm_runtime_get_noresume(dev);
1152         spin_lock_irq(&dev->power.lock);
1153
1154         if (dev->power.request_pending
1155             && dev->power.request == RPM_REQ_RESUME) {
1156                 rpm_resume(dev, 0);
1157                 retval = 1;
1158         }
1159
1160         __pm_runtime_barrier(dev);
1161
1162         spin_unlock_irq(&dev->power.lock);
1163         pm_runtime_put_noidle(dev);
1164
1165         return retval;
1166 }
1167 EXPORT_SYMBOL_GPL(pm_runtime_barrier);
1168
1169 /**
1170  * __pm_runtime_disable - Disable runtime PM of a device.
1171  * @dev: Device to handle.
1172  * @check_resume: If set, check if there's a resume request for the device.
1173  *
1174  * Increment power.disable_depth for the device and if it was zero previously,
1175  * cancel all pending runtime PM requests for the device and wait for all
1176  * operations in progress to complete.  The device can be either active or
1177  * suspended after its runtime PM has been disabled.
1178  *
1179  * If @check_resume is set and there's a resume request pending when
1180  * __pm_runtime_disable() is called and power.disable_depth is zero, the
1181  * function will wake up the device before disabling its runtime PM.
1182  */
1183 void __pm_runtime_disable(struct device *dev, bool check_resume)
1184 {
1185         spin_lock_irq(&dev->power.lock);
1186
1187         if (dev->power.disable_depth > 0) {
1188                 dev->power.disable_depth++;
1189                 goto out;
1190         }
1191
1192         /*
1193          * Wake up the device if there's a resume request pending, because that
1194          * means there probably is some I/O to process and disabling runtime PM
1195          * shouldn't prevent the device from processing the I/O.
1196          */
1197         if (check_resume && dev->power.request_pending
1198             && dev->power.request == RPM_REQ_RESUME) {
1199                 /*
1200                  * Prevent suspends and idle notifications from being carried
1201                  * out after we have woken up the device.
1202                  */
1203                 pm_runtime_get_noresume(dev);
1204
1205                 rpm_resume(dev, 0);
1206
1207                 pm_runtime_put_noidle(dev);
1208         }
1209
1210         if (!dev->power.disable_depth++)
1211                 __pm_runtime_barrier(dev);
1212
1213  out:
1214         spin_unlock_irq(&dev->power.lock);
1215 }
1216 EXPORT_SYMBOL_GPL(__pm_runtime_disable);
1217
1218 /**
1219  * pm_runtime_enable - Enable runtime PM of a device.
1220  * @dev: Device to handle.
1221  */
1222 void pm_runtime_enable(struct device *dev)
1223 {
1224         unsigned long flags;
1225
1226         spin_lock_irqsave(&dev->power.lock, flags);
1227
1228         if (dev->power.disable_depth > 0)
1229                 dev->power.disable_depth--;
1230         else
1231                 dev_warn(dev, "Unbalanced %s!\n", __func__);
1232
1233         spin_unlock_irqrestore(&dev->power.lock, flags);
1234 }
1235 EXPORT_SYMBOL_GPL(pm_runtime_enable);
1236
1237 /**
1238  * pm_runtime_forbid - Block runtime PM of a device.
1239  * @dev: Device to handle.
1240  *
1241  * Increase the device's usage count and clear its power.runtime_auto flag,
1242  * so that it cannot be suspended at run time until pm_runtime_allow() is called
1243  * for it.
1244  */
1245 void pm_runtime_forbid(struct device *dev)
1246 {
1247         spin_lock_irq(&dev->power.lock);
1248         if (!dev->power.runtime_auto)
1249                 goto out;
1250
1251         dev->power.runtime_auto = false;
1252         atomic_inc(&dev->power.usage_count);
1253         rpm_resume(dev, 0);
1254
1255  out:
1256         spin_unlock_irq(&dev->power.lock);
1257 }
1258 EXPORT_SYMBOL_GPL(pm_runtime_forbid);
1259
1260 /**
1261  * pm_runtime_allow - Unblock runtime PM of a device.
1262  * @dev: Device to handle.
1263  *
1264  * Decrease the device's usage count and set its power.runtime_auto flag.
1265  */
1266 void pm_runtime_allow(struct device *dev)
1267 {
1268         spin_lock_irq(&dev->power.lock);
1269         if (dev->power.runtime_auto)
1270                 goto out;
1271
1272         dev->power.runtime_auto = true;
1273         if (atomic_dec_and_test(&dev->power.usage_count))
1274                 rpm_idle(dev, RPM_AUTO | RPM_ASYNC);
1275
1276  out:
1277         spin_unlock_irq(&dev->power.lock);
1278 }
1279 EXPORT_SYMBOL_GPL(pm_runtime_allow);
1280
1281 /**
1282  * pm_runtime_no_callbacks - Ignore runtime PM callbacks for a device.
1283  * @dev: Device to handle.
1284  *
1285  * Set the power.no_callbacks flag, which tells the PM core that this
1286  * device is power-managed through its parent and has no runtime PM
1287  * callbacks of its own.  The runtime sysfs attributes will be removed.
1288  */
1289 void pm_runtime_no_callbacks(struct device *dev)
1290 {
1291         spin_lock_irq(&dev->power.lock);
1292         dev->power.no_callbacks = 1;
1293         spin_unlock_irq(&dev->power.lock);
1294         if (device_is_registered(dev))
1295                 rpm_sysfs_remove(dev);
1296 }
1297 EXPORT_SYMBOL_GPL(pm_runtime_no_callbacks);
1298
1299 /**
1300  * pm_runtime_irq_safe - Leave interrupts disabled during callbacks.
1301  * @dev: Device to handle
1302  *
1303  * Set the power.irq_safe flag, which tells the PM core that the
1304  * ->runtime_suspend() and ->runtime_resume() callbacks for this device should
1305  * always be invoked with the spinlock held and interrupts disabled.  It also
1306  * causes the parent's usage counter to be permanently incremented, preventing
1307  * the parent from runtime suspending -- otherwise an irq-safe child might have
1308  * to wait for a non-irq-safe parent.
1309  */
1310 void pm_runtime_irq_safe(struct device *dev)
1311 {
1312         if (dev->parent)
1313                 pm_runtime_get_sync(dev->parent);
1314         spin_lock_irq(&dev->power.lock);
1315         dev->power.irq_safe = 1;
1316         spin_unlock_irq(&dev->power.lock);
1317 }
1318 EXPORT_SYMBOL_GPL(pm_runtime_irq_safe);
1319
1320 /**
1321  * update_autosuspend - Handle a change to a device's autosuspend settings.
1322  * @dev: Device to handle.
1323  * @old_delay: The former autosuspend_delay value.
1324  * @old_use: The former use_autosuspend value.
1325  *
1326  * Prevent runtime suspend if the new delay is negative and use_autosuspend is
1327  * set; otherwise allow it.  Send an idle notification if suspends are allowed.
1328  *
1329  * This function must be called under dev->power.lock with interrupts disabled.
1330  */
1331 static void update_autosuspend(struct device *dev, int old_delay, int old_use)
1332 {
1333         int delay = dev->power.autosuspend_delay;
1334
1335         /* Should runtime suspend be prevented now? */
1336         if (dev->power.use_autosuspend && delay < 0) {
1337
1338                 /* If it used to be allowed then prevent it. */
1339                 if (!old_use || old_delay >= 0) {
1340                         atomic_inc(&dev->power.usage_count);
1341                         rpm_resume(dev, 0);
1342                 }
1343         }
1344
1345         /* Runtime suspend should be allowed now. */
1346         else {
1347
1348                 /* If it used to be prevented then allow it. */
1349                 if (old_use && old_delay < 0)
1350                         atomic_dec(&dev->power.usage_count);
1351
1352                 /* Maybe we can autosuspend now. */
1353                 rpm_idle(dev, RPM_AUTO);
1354         }
1355 }
1356
1357 /**
1358  * pm_runtime_set_autosuspend_delay - Set a device's autosuspend_delay value.
1359  * @dev: Device to handle.
1360  * @delay: Value of the new delay in milliseconds.
1361  *
1362  * Set the device's power.autosuspend_delay value.  If it changes to negative
1363  * and the power.use_autosuspend flag is set, prevent runtime suspends.  If it
1364  * changes the other way, allow runtime suspends.
1365  */
1366 void pm_runtime_set_autosuspend_delay(struct device *dev, int delay)
1367 {
1368         int old_delay, old_use;
1369
1370         spin_lock_irq(&dev->power.lock);
1371         old_delay = dev->power.autosuspend_delay;
1372         old_use = dev->power.use_autosuspend;
1373         dev->power.autosuspend_delay = delay;
1374         update_autosuspend(dev, old_delay, old_use);
1375         spin_unlock_irq(&dev->power.lock);
1376 }
1377 EXPORT_SYMBOL_GPL(pm_runtime_set_autosuspend_delay);
1378
1379 /**
1380  * __pm_runtime_use_autosuspend - Set a device's use_autosuspend flag.
1381  * @dev: Device to handle.
1382  * @use: New value for use_autosuspend.
1383  *
1384  * Set the device's power.use_autosuspend flag, and allow or prevent runtime
1385  * suspends as needed.
1386  */
1387 void __pm_runtime_use_autosuspend(struct device *dev, bool use)
1388 {
1389         int old_delay, old_use;
1390
1391         spin_lock_irq(&dev->power.lock);
1392         old_delay = dev->power.autosuspend_delay;
1393         old_use = dev->power.use_autosuspend;
1394         dev->power.use_autosuspend = use;
1395         update_autosuspend(dev, old_delay, old_use);
1396         spin_unlock_irq(&dev->power.lock);
1397 }
1398 EXPORT_SYMBOL_GPL(__pm_runtime_use_autosuspend);
1399
1400 /**
1401  * pm_runtime_init - Initialize runtime PM fields in given device object.
1402  * @dev: Device object to initialize.
1403  */
1404 void pm_runtime_init(struct device *dev)
1405 {
1406         dev->power.runtime_status = RPM_SUSPENDED;
1407         dev->power.idle_notification = false;
1408
1409         dev->power.disable_depth = 1;
1410         atomic_set(&dev->power.usage_count, 0);
1411
1412         dev->power.runtime_error = 0;
1413
1414         atomic_set(&dev->power.child_count, 0);
1415         pm_suspend_ignore_children(dev, false);
1416         dev->power.runtime_auto = true;
1417
1418         dev->power.request_pending = false;
1419         dev->power.request = RPM_REQ_NONE;
1420         dev->power.deferred_resume = false;
1421         dev->power.accounting_timestamp = jiffies;
1422         INIT_WORK(&dev->power.work, pm_runtime_work);
1423
1424         dev->power.timer_expires = 0;
1425         setup_timer(&dev->power.suspend_timer, pm_suspend_timer_fn,
1426                         (unsigned long)dev);
1427
1428         init_waitqueue_head(&dev->power.wait_queue);
1429 }
1430
1431 /**
1432  * pm_runtime_reinit - Re-initialize runtime PM fields in given device object.
1433  * @dev: Device object to re-initialize.
1434  */
1435 void pm_runtime_reinit(struct device *dev)
1436 {
1437         if (!pm_runtime_enabled(dev)) {
1438                 if (dev->power.runtime_status == RPM_ACTIVE)
1439                         pm_runtime_set_suspended(dev);
1440                 if (dev->power.irq_safe) {
1441                         spin_lock_irq(&dev->power.lock);
1442                         dev->power.irq_safe = 0;
1443                         spin_unlock_irq(&dev->power.lock);
1444                         if (dev->parent)
1445                                 pm_runtime_put(dev->parent);
1446                 }
1447         }
1448 }
1449
1450 /**
1451  * pm_runtime_remove - Prepare for removing a device from device hierarchy.
1452  * @dev: Device object being removed from device hierarchy.
1453  */
1454 void pm_runtime_remove(struct device *dev)
1455 {
1456         __pm_runtime_disable(dev, false);
1457         pm_runtime_reinit(dev);
1458 }
1459
1460 /**
1461  * pm_runtime_force_suspend - Force a device into suspend state if needed.
1462  * @dev: Device to suspend.
1463  *
1464  * Disable runtime PM so we safely can check the device's runtime PM status and
1465  * if it is active, invoke it's .runtime_suspend callback to bring it into
1466  * suspend state. Keep runtime PM disabled to preserve the state unless we
1467  * encounter errors.
1468  *
1469  * Typically this function may be invoked from a system suspend callback to make
1470  * sure the device is put into low power state.
1471  */
1472 int pm_runtime_force_suspend(struct device *dev)
1473 {
1474         int (*callback)(struct device *);
1475         int ret = 0;
1476
1477         pm_runtime_disable(dev);
1478         if (pm_runtime_status_suspended(dev))
1479                 return 0;
1480
1481         callback = RPM_GET_CALLBACK(dev, runtime_suspend);
1482
1483         if (!callback) {
1484                 ret = -ENOSYS;
1485                 goto err;
1486         }
1487
1488         ret = callback(dev);
1489         if (ret)
1490                 goto err;
1491
1492         /*
1493          * Increase the runtime PM usage count for the device's parent, in case
1494          * when we find the device being used when system suspend was invoked.
1495          * This informs pm_runtime_force_resume() to resume the parent
1496          * immediately, which is needed to be able to resume its children,
1497          * when not deferring the resume to be managed via runtime PM.
1498          */
1499         if (dev->parent && atomic_read(&dev->power.usage_count) > 1)
1500                 pm_runtime_get_noresume(dev->parent);
1501
1502         pm_runtime_set_suspended(dev);
1503         return 0;
1504 err:
1505         pm_runtime_enable(dev);
1506         return ret;
1507 }
1508 EXPORT_SYMBOL_GPL(pm_runtime_force_suspend);
1509
1510 /**
1511  * pm_runtime_force_resume - Force a device into resume state if needed.
1512  * @dev: Device to resume.
1513  *
1514  * Prior invoking this function we expect the user to have brought the device
1515  * into low power state by a call to pm_runtime_force_suspend(). Here we reverse
1516  * those actions and brings the device into full power, if it is expected to be
1517  * used on system resume. To distinguish that, we check whether the runtime PM
1518  * usage count is greater than 1 (the PM core increases the usage count in the
1519  * system PM prepare phase), as that indicates a real user (such as a subsystem,
1520  * driver, userspace, etc.) is using it. If that is the case, the device is
1521  * expected to be used on system resume as well, so then we resume it. In the
1522  * other case, we defer the resume to be managed via runtime PM.
1523  *
1524  * Typically this function may be invoked from a system resume callback.
1525  */
1526 int pm_runtime_force_resume(struct device *dev)
1527 {
1528         int (*callback)(struct device *);
1529         int ret = 0;
1530
1531         callback = RPM_GET_CALLBACK(dev, runtime_resume);
1532
1533         if (!callback) {
1534                 ret = -ENOSYS;
1535                 goto out;
1536         }
1537
1538         if (!pm_runtime_status_suspended(dev))
1539                 goto out;
1540
1541         /*
1542          * Decrease the parent's runtime PM usage count, if we increased it
1543          * during system suspend in pm_runtime_force_suspend().
1544         */
1545         if (atomic_read(&dev->power.usage_count) > 1) {
1546                 if (dev->parent)
1547                         pm_runtime_put_noidle(dev->parent);
1548         } else {
1549                 goto out;
1550         }
1551
1552         ret = pm_runtime_set_active(dev);
1553         if (ret)
1554                 goto out;
1555
1556         ret = callback(dev);
1557         if (ret) {
1558                 pm_runtime_set_suspended(dev);
1559                 goto out;
1560         }
1561
1562         pm_runtime_mark_last_busy(dev);
1563 out:
1564         pm_runtime_enable(dev);
1565         return ret;
1566 }
1567 EXPORT_SYMBOL_GPL(pm_runtime_force_resume);