drivers/base/power/runtime.c

   1 /*
   2  * drivers/base/power/runtime.c - Helper functions for device runtime PM
   3  *
   4  * Copyright (c) 2009 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc.
   5  * Copyright (C) 2010 Alan Stern <stern@rowland.harvard.edu>
   6  *
   7  * This file is released under the GPLv2.
   8  */
   9
  10 #include <linux/sched.h>
  11 #include <linux/export.h>
  12 #include <linux/pm_runtime.h>
  13 #include <trace/events/rpm.h>
  14 #include "power.h"
  15
  16 static int rpm_resume(struct device *dev, int rpmflags);
  17 static int rpm_suspend(struct device *dev, int rpmflags);
  18
  19 /**
  20  * update_pm_runtime_accounting - Update the time accounting of power states
  21  * @dev: Device to update the accounting for
  22  *
  23  * In order to be able to have time accounting of the various power states
  24  * (as used by programs such as PowerTOP to show the effectiveness of runtime
  25  * PM), we need to track the time spent in each state.
  26  * update_pm_runtime_accounting must be called each time before the
  27  * runtime_status field is updated, to account the time in the old state
  28  * correctly.
  29  */
  30 void update_pm_runtime_accounting(struct device *dev)
  31 {
  32         unsigned long now = jiffies;
  33         unsigned long delta;
  34
  35         delta = now - dev->power.accounting_timestamp;
  36
  37         dev->power.accounting_timestamp = now;
  38
  39         if (dev->power.disable_depth > 0)
  40                 return;
  41
  42         if (dev->power.runtime_status == RPM_SUSPENDED)
  43                 dev->power.suspended_jiffies += delta;
  44         else
  45                 dev->power.active_jiffies += delta;
  46 }
  47
  48 static void __update_runtime_status(struct device *dev, enum rpm_status status)
  49 {
  50         update_pm_runtime_accounting(dev);
  51         dev->power.runtime_status = status;
  52 }
  53
  54 /**
  55  * pm_runtime_deactivate_timer - Deactivate given device's suspend timer.
  56  * @dev: Device to handle.
  57  */
  58 static void pm_runtime_deactivate_timer(struct device *dev)
  59 {
  60         if (dev->power.timer_expires > 0) {
  61                 del_timer(&dev->power.suspend_timer);
  62                 dev->power.timer_expires = 0;
  63         }
  64 }
  65
  66 /**
  67  * pm_runtime_cancel_pending - Deactivate suspend timer and cancel requests.
  68  * @dev: Device to handle.
  69  */
  70 static void pm_runtime_cancel_pending(struct device *dev)
  71 {
  72         pm_runtime_deactivate_timer(dev);
  73         /*
  74          * In case there's a request pending, make sure its work function will
  75          * return without doing anything.
  76          */
  77         dev->power.request = RPM_REQ_NONE;
  78 }
  79
  80 /*
  81  * pm_runtime_autosuspend_expiration - Get a device's autosuspend-delay expiration time.
  82  * @dev: Device to handle.
  83  *
  84  * Compute the autosuspend-delay expiration time based on the device's
  85  * power.last_busy time.  If the delay has already expired or is disabled
  86  * (negative) or the power.use_autosuspend flag isn't set, return 0.
  87  * Otherwise return the expiration time in jiffies (adjusted to be nonzero).
  88  *
  89  * This function may be called either with or without dev->power.lock held.
  90  * Either way it can be racy, since power.last_busy may be updated at any time.
  91  */
  92 unsigned long pm_runtime_autosuspend_expiration(struct device *dev)
  93 {
  94         int autosuspend_delay;
  95         long elapsed;
  96         unsigned long last_busy;
  97         unsigned long expires = 0;
  98
  99         if (!dev->power.use_autosuspend)
 100                 goto out;
 101
 102         autosuspend_delay = ACCESS_ONCE(dev->power.autosuspend_delay);
 103         if (autosuspend_delay < 0)
 104                 goto out;
 105
 106         last_busy = ACCESS_ONCE(dev->power.last_busy);
 107         elapsed = jiffies - last_busy;
 108         if (elapsed < 0)
 109                 goto out;       /* jiffies has wrapped around. */
 110
 111         /*
 112          * If the autosuspend_delay is >= 1 second, align the timer by rounding
 113          * up to the nearest second.
 114          */
 115         expires = last_busy + msecs_to_jiffies(autosuspend_delay);
 116         if (autosuspend_delay >= 1000)
 117                 expires = round_jiffies(expires);
 118         expires += !expires;
 119         if (elapsed >= expires - last_busy)
 120                 expires = 0;    /* Already expired. */
 121
 122  out:
 123         return expires;
 124 }
 125 EXPORT_SYMBOL_GPL(pm_runtime_autosuspend_expiration);
 126
 127 /**
 128  * rpm_check_suspend_allowed - Test whether a device may be suspended.
 129  * @dev: Device to test.
 130  */
 131 static int rpm_check_suspend_allowed(struct device *dev)
 132 {
 133         int retval = 0;
 134
 135         if (dev->power.runtime_error)
 136                 retval = -EINVAL;
 137         else if (dev->power.disable_depth > 0)
 138                 retval = -EACCES;
 139         else if (atomic_read(&dev->power.usage_count) > 0)
 140                 retval = -EAGAIN;
 141         else if (!pm_children_suspended(dev))
 142                 retval = -EBUSY;
 143
 144         /* Pending resume requests take precedence over suspends. */
 145         else if ((dev->power.deferred_resume
 146                         && dev->power.runtime_status == RPM_SUSPENDING)
 147             || (dev->power.request_pending
 148                         && dev->power.request == RPM_REQ_RESUME))
 149                 retval = -EAGAIN;
 150         else if (dev->power.runtime_status == RPM_SUSPENDED)
 151                 retval = 1;
 152
 153         return retval;
 154 }
 155
 156 /**
 157  * __rpm_callback - Run a given runtime PM callback for a given device.
 158  * @cb: Runtime PM callback to run.
 159  * @dev: Device to run the callback for.
 160  */
 161 static int __rpm_callback(int (*cb)(struct device *), struct device *dev)
 162         __releases(&dev->power.lock) __acquires(&dev->power.lock)
 163 {
 164         int retval;
 165
 166         if (dev->power.irq_safe)
 167                 spin_unlock(&dev->power.lock);
 168         else
 169                 spin_unlock_irq(&dev->power.lock);
 170
 171         retval = cb(dev);
 172
 173         if (dev->power.irq_safe)
 174                 spin_lock(&dev->power.lock);
 175         else
 176                 spin_lock_irq(&dev->power.lock);
 177
 178         return retval;
 179 }
 180
 181 /**
 182  * rpm_idle - Notify device bus type if the device can be suspended.
 183  * @dev: Device to notify the bus type about.
 184  * @rpmflags: Flag bits.
 185  *
 186  * Check if the device's runtime PM status allows it to be suspended.  If
 187  * another idle notification has been started earlier, return immediately.  If
 188  * the RPM_ASYNC flag is set then queue an idle-notification request; otherwise
 189  * run the ->runtime_idle() callback directly.
 190  *
 191  * This function must be called under dev->power.lock with interrupts disabled.
 192  */
 193 static int rpm_idle(struct device *dev, int rpmflags)
 194 {
 195         int (*callback)(struct device *);
 196         int retval;
 197
 198         trace_rpm_idle(dev, rpmflags);
 199         retval = rpm_check_suspend_allowed(dev);
 200         if (retval < 0)
 201                 ;       /* Conditions are wrong. */
 202
 203         /* Idle notifications are allowed only in the RPM_ACTIVE state. */
 204         else if (dev->power.runtime_status != RPM_ACTIVE)
 205                 retval = -EAGAIN;
 206
 207         /*
 208          * Any pending request other than an idle notification takes
 209          * precedence over us, except that the timer may be running.
 210          */
 211         else if (dev->power.request_pending &&
 212             dev->power.request > RPM_REQ_IDLE)
 213                 retval = -EAGAIN;
 214
 215         /* Act as though RPM_NOWAIT is always set. */
 216         else if (dev->power.idle_notification)
 217                 retval = -EINPROGRESS;
 218         if (retval)
 219                 goto out;
 220
 221         /* Pending requests need to be canceled. */
 222         dev->power.request = RPM_REQ_NONE;
 223
 224         if (dev->power.no_callbacks) {
 225                 /* Assume ->runtime_idle() callback would have suspended. */
 226                 retval = rpm_suspend(dev, rpmflags);
 227                 goto out;
 228         }
 229
 230         /* Carry out an asynchronous or a synchronous idle notification. */
 231         if (rpmflags & RPM_ASYNC) {
 232                 dev->power.request = RPM_REQ_IDLE;
 233                 if (!dev->power.request_pending) {
 234                         dev->power.request_pending = true;
 235                         queue_work(pm_wq, &dev->power.work);
 236                 }
 237                 goto out;
 238         }
 239
 240         dev->power.idle_notification = true;
 241
 242         if (dev->pm_domain)
 243                 callback = dev->pm_domain->ops.runtime_idle;
 244         else if (dev->type && dev->type->pm)
 245                 callback = dev->type->pm->runtime_idle;
 246         else if (dev->class && dev->class->pm)
 247                 callback = dev->class->pm->runtime_idle;
 248         else if (dev->bus && dev->bus->pm)
 249                 callback = dev->bus->pm->runtime_idle;
 250         else
 251                 callback = NULL;
 252
 253         if (callback)
 254                 __rpm_callback(callback, dev);
 255
 256         dev->power.idle_notification = false;
 257         wake_up_all(&dev->power.wait_queue);
 258
 259  out:
 260         trace_rpm_return_int(dev, _THIS_IP_, retval);
 261         return retval;
 262 }
 263
 264 /**
 265  * rpm_callback - Run a given runtime PM callback for a given device.
 266  * @cb: Runtime PM callback to run.
 267  * @dev: Device to run the callback for.
 268  */
 269 static int rpm_callback(int (*cb)(struct device *), struct device *dev)
 270 {
 271         int retval;
 272
 273         if (!cb)
 274                 return -ENOSYS;
 275
 276         retval = __rpm_callback(cb, dev);
 277
 278         dev->power.runtime_error = retval;
 279         return retval != -EACCES ? retval : -EIO;
 280 }
 281
 282 struct rpm_qos_data {
 283         ktime_t time_now;
 284         s64 constraint_ns;
 285 };
 286
 287 /**
 288  * rpm_update_qos_constraint - Update a given PM QoS constraint data.
 289  * @dev: Device whose timing data to use.
 290  * @data: PM QoS constraint data to update.
 291  *
 292  * Use the suspend timing data of @dev to update PM QoS constraint data pointed
 293  * to by @data.
 294  */
 295 static int rpm_update_qos_constraint(struct device *dev, void *data)
 296 {
 297         struct rpm_qos_data *qos = data;
 298         unsigned long flags;
 299         s64 delta_ns;
 300         int ret = 0;
 301
 302         spin_lock_irqsave(&dev->power.lock, flags);
 303
 304         if (dev->power.max_time_suspended_ns < 0)
 305                 goto out;
 306
 307         delta_ns = dev->power.max_time_suspended_ns -
 308                 ktime_to_ns(ktime_sub(qos->time_now, dev->power.suspend_time));
 309         if (delta_ns <= 0) {
 310                 ret = -EBUSY;
 311                 goto out;
 312         }
 313
 314         if (qos->constraint_ns > delta_ns || qos->constraint_ns == 0)
 315                 qos->constraint_ns = delta_ns;
 316
 317  out:
 318         spin_unlock_irqrestore(&dev->power.lock, flags);
 319
 320         return ret;
 321 }
 322
 323 /**
 324  * rpm_suspend - Carry out runtime suspend of given device.
 325  * @dev: Device to suspend.
 326  * @rpmflags: Flag bits.
 327  *
 328  * Check if the device's runtime PM status allows it to be suspended.
 329  * Cancel a pending idle notification, autosuspend or suspend. If
 330  * another suspend has been started earlier, either return immediately
 331  * or wait for it to finish, depending on the RPM_NOWAIT and RPM_ASYNC
 332  * flags. If the RPM_ASYNC flag is set then queue a suspend request;
 333  * otherwise run the ->runtime_suspend() callback directly. When
 334  * ->runtime_suspend succeeded, if a deferred resume was requested while
 335  * the callback was running then carry it out, otherwise send an idle
 336  * notification for its parent (if the suspend succeeded and both
 337  * ignore_children of parent->power and irq_safe of dev->power are not set).
 338  * If ->runtime_suspend failed with -EAGAIN or -EBUSY, and if the RPM_AUTO
 339  * flag is set and the next autosuspend-delay expiration time is in the
 340  * future, schedule another autosuspend attempt.
 341  *
 342  * This function must be called under dev->power.lock with interrupts disabled.
 343  */
 344 static int rpm_suspend(struct device *dev, int rpmflags)
 345         __releases(&dev->power.lock) __acquires(&dev->power.lock)
 346 {
 347         int (*callback)(struct device *);
 348         struct device *parent = NULL;
 349         struct rpm_qos_data qos;
 350         int retval;
 351
 352         trace_rpm_suspend(dev, rpmflags);
 353
 354  repeat:
 355         retval = rpm_check_suspend_allowed(dev);
 356
 357         if (retval < 0)
 358                 ;       /* Conditions are wrong. */
 359
 360         /* Synchronous suspends are not allowed in the RPM_RESUMING state. */
 361         else if (dev->power.runtime_status == RPM_RESUMING &&
 362             !(rpmflags & RPM_ASYNC))
 363                 retval = -EAGAIN;
 364         if (retval)
 365                 goto out;
 366
 367         /* If the autosuspend_delay time hasn't expired yet, reschedule. */
 368         if ((rpmflags & RPM_AUTO)
 369             && dev->power.runtime_status != RPM_SUSPENDING) {
 370                 unsigned long expires = pm_runtime_autosuspend_expiration(dev);
 371
 372                 if (expires != 0) {
 373                         /* Pending requests need to be canceled. */
 374                         dev->power.request = RPM_REQ_NONE;
 375
 376                         /*
 377                          * Optimization: If the timer is already running and is
 378                          * set to expire at or before the autosuspend delay,
 379                          * avoid the overhead of resetting it.  Just let it
 380                          * expire; pm_suspend_timer_fn() will take care of the
 381                          * rest.
 382                          */
 383                         if (!(dev->power.timer_expires && time_before_eq(
 384                             dev->power.timer_expires, expires))) {
 385                                 dev->power.timer_expires = expires;
 386                                 mod_timer(&dev->power.suspend_timer, expires);
 387                         }
 388                         dev->power.timer_autosuspends = 1;
 389                         goto out;
 390                 }
 391         }
 392
 393         /* Other scheduled or pending requests need to be canceled. */
 394         pm_runtime_cancel_pending(dev);
 395
 396         if (dev->power.runtime_status == RPM_SUSPENDING) {
 397                 DEFINE_WAIT(wait);
 398
 399                 if (rpmflags & (RPM_ASYNC | RPM_NOWAIT)) {
 400                         retval = -EINPROGRESS;
 401                         goto out;
 402                 }
 403
 404                 if (dev->power.irq_safe) {
 405                         spin_unlock(&dev->power.lock);
 406
 407                         cpu_relax();
 408
 409                         spin_lock(&dev->power.lock);
 410                         goto repeat;
 411                 }
 412
 413                 /* Wait for the other suspend running in parallel with us. */
 414                 for (;;) {
 415                         prepare_to_wait(&dev->power.wait_queue, &wait,
 416                                         TASK_UNINTERRUPTIBLE);
 417                         if (dev->power.runtime_status != RPM_SUSPENDING)
 418                                 break;
 419
 420                         spin_unlock_irq(&dev->power.lock);
 421
 422                         schedule();
 423
 424                         spin_lock_irq(&dev->power.lock);
 425                 }
 426                 finish_wait(&dev->power.wait_queue, &wait);
 427                 goto repeat;
 428         }
 429
 430         dev->power.deferred_resume = false;
 431         if (dev->power.no_callbacks)
 432                 goto no_callback;       /* Assume success. */
 433
 434         /* Carry out an asynchronous or a synchronous suspend. */
 435         if (rpmflags & RPM_ASYNC) {
 436                 dev->power.request = (rpmflags & RPM_AUTO) ?
 437                     RPM_REQ_AUTOSUSPEND : RPM_REQ_SUSPEND;
 438                 if (!dev->power.request_pending) {
 439                         dev->power.request_pending = true;
 440                         queue_work(pm_wq, &dev->power.work);
 441                 }
 442                 goto out;
 443         }
 444
 445         qos.constraint_ns = __dev_pm_qos_read_value(dev);
 446         if (qos.constraint_ns < 0) {
 447                 /* Negative constraint means "never suspend". */
 448                 retval = -EPERM;
 449                 goto out;
 450         }
 451         qos.constraint_ns *= NSEC_PER_USEC;
 452         qos.time_now = ktime_get();
 453
 454         __update_runtime_status(dev, RPM_SUSPENDING);
 455
 456         if (!dev->power.ignore_children) {
 457                 if (dev->power.irq_safe)
 458                         spin_unlock(&dev->power.lock);
 459                 else
 460                         spin_unlock_irq(&dev->power.lock);
 461
 462                 retval = device_for_each_child(dev, &qos,
 463                                                rpm_update_qos_constraint);
 464
 465                 if (dev->power.irq_safe)
 466                         spin_lock(&dev->power.lock);
 467                 else
 468                         spin_lock_irq(&dev->power.lock);
 469
 470                 if (retval)
 471                         goto fail;
 472         }
 473
 474         dev->power.suspend_time = qos.time_now;
 475         dev->power.max_time_suspended_ns = qos.constraint_ns ? : -1;
 476
 477         if (dev->pm_domain)
 478                 callback = dev->pm_domain->ops.runtime_suspend;
 479         else if (dev->type && dev->type->pm)
 480                 callback = dev->type->pm->runtime_suspend;
 481         else if (dev->class && dev->class->pm)
 482                 callback = dev->class->pm->runtime_suspend;
 483         else if (dev->bus && dev->bus->pm)
 484                 callback = dev->bus->pm->runtime_suspend;
 485         else
 486                 callback = NULL;
 487
 488         retval = rpm_callback(callback, dev);
 489         if (retval)
 490                 goto fail;
 491
 492  no_callback:
 493         __update_runtime_status(dev, RPM_SUSPENDED);
 494         pm_runtime_deactivate_timer(dev);
 495
 496         if (dev->parent) {
 497                 parent = dev->parent;
 498                 atomic_add_unless(&parent->power.child_count, -1, 0);
 499         }
 500         wake_up_all(&dev->power.wait_queue);
 501
 502         if (dev->power.deferred_resume) {
 503                 rpm_resume(dev, 0);
 504                 retval = -EAGAIN;
 505                 goto out;
 506         }
 507
 508         /* Maybe the parent is now able to suspend. */
 509         if (parent && !parent->power.ignore_children && !dev->power.irq_safe) {
 510                 spin_unlock(&dev->power.lock);
 511
 512                 spin_lock(&parent->power.lock);
 513                 rpm_idle(parent, RPM_ASYNC);
 514                 spin_unlock(&parent->power.lock);
 515
 516                 spin_lock(&dev->power.lock);
 517         }
 518
 519  out:
 520         trace_rpm_return_int(dev, _THIS_IP_, retval);
 521
 522         return retval;
 523
 524  fail:
 525         __update_runtime_status(dev, RPM_ACTIVE);
 526         dev->power.suspend_time = ktime_set(0, 0);
 527         dev->power.max_time_suspended_ns = -1;
 528         dev->power.deferred_resume = false;
 529         if (retval == -EAGAIN || retval == -EBUSY) {
 530                 dev->power.runtime_error = 0;
 531
 532                 /*
 533                  * If the callback routine failed an autosuspend, and
 534                  * if the last_busy time has been updated so that there
 535                  * is a new autosuspend expiration time, automatically
 536                  * reschedule another autosuspend.
 537                  */
 538                 if ((rpmflags & RPM_AUTO) &&
 539                     pm_runtime_autosuspend_expiration(dev) != 0)
 540                         goto repeat;
 541         } else {
 542                 pm_runtime_cancel_pending(dev);
 543         }
 544         wake_up_all(&dev->power.wait_queue);
 545         goto out;
 546 }
 547
 548 /**
 549  * rpm_resume - Carry out runtime resume of given device.
 550  * @dev: Device to resume.
 551  * @rpmflags: Flag bits.
 552  *
 553  * Check if the device's runtime PM status allows it to be resumed.  Cancel
 554  * any scheduled or pending requests.  If another resume has been started
 555  * earlier, either return immediately or wait for it to finish, depending on the
 556  * RPM_NOWAIT and RPM_ASYNC flags.  Similarly, if there's a suspend running in
 557  * parallel with this function, either tell the other process to resume after
 558  * suspending (deferred_resume) or wait for it to finish.  If the RPM_ASYNC
 559  * flag is set then queue a resume request; otherwise run the
 560  * ->runtime_resume() callback directly.  Queue an idle notification for the
 561  * device if the resume succeeded.
 562  *
 563  * This function must be called under dev->power.lock with interrupts disabled.
 564  */
 565 static int rpm_resume(struct device *dev, int rpmflags)
 566         __releases(&dev->power.lock) __acquires(&dev->power.lock)
 567 {
 568         int (*callback)(struct device *);
 569         struct device *parent = NULL;
 570         int retval = 0;
 571
 572         trace_rpm_resume(dev, rpmflags);
 573
 574  repeat:
 575         if (dev->power.runtime_error)
 576                 retval = -EINVAL;
 577         else if (dev->power.disable_depth > 0)
 578                 retval = -EACCES;
 579         if (retval)
 580                 goto out;
 581
 582         /*
 583          * Other scheduled or pending requests need to be canceled.  Small
 584          * optimization: If an autosuspend timer is running, leave it running
 585          * rather than cancelling it now only to restart it again in the near
 586          * future.
 587          */
 588         dev->power.request = RPM_REQ_NONE;
 589         if (!dev->power.timer_autosuspends)
 590                 pm_runtime_deactivate_timer(dev);
 591
 592         if (dev->power.runtime_status == RPM_ACTIVE) {
 593                 retval = 1;
 594                 goto out;
 595         }
 596
 597         if (dev->power.runtime_status == RPM_RESUMING
 598             || dev->power.runtime_status == RPM_SUSPENDING) {
 599                 DEFINE_WAIT(wait);
 600
 601                 if (rpmflags & (RPM_ASYNC | RPM_NOWAIT)) {
 602                         if (dev->power.runtime_status == RPM_SUSPENDING)
 603                                 dev->power.deferred_resume = true;
 604                         else
 605                                 retval = -EINPROGRESS;
 606                         goto out;
 607                 }
 608
 609                 if (dev->power.irq_safe) {
 610                         spin_unlock(&dev->power.lock);
 611
 612                         cpu_relax();
 613
 614                         spin_lock(&dev->power.lock);
 615                         goto repeat;
 616                 }
 617
 618                 /* Wait for the operation carried out in parallel with us. */
 619                 for (;;) {
 620                         prepare_to_wait(&dev->power.wait_queue, &wait,
 621                                         TASK_UNINTERRUPTIBLE);
 622                         if (dev->power.runtime_status != RPM_RESUMING
 623                             && dev->power.runtime_status != RPM_SUSPENDING)
 624                                 break;
 625
 626                         spin_unlock_irq(&dev->power.lock);
 627
 628                         schedule();
 629
 630                         spin_lock_irq(&dev->power.lock);
 631                 }
 632                 finish_wait(&dev->power.wait_queue, &wait);
 633                 goto repeat;
 634         }
 635
 636         /*
 637          * See if we can skip waking up the parent.  This is safe only if
 638          * power.no_callbacks is set, because otherwise we don't know whether
 639          * the resume will actually succeed.
 640          */
 641         if (dev->power.no_callbacks && !parent && dev->parent) {
 642                 spin_lock_nested(&dev->parent->power.lock, SINGLE_DEPTH_NESTING);
 643                 if (dev->parent->power.disable_depth > 0
 644                     || dev->parent->power.ignore_children
 645                     || dev->parent->power.runtime_status == RPM_ACTIVE) {
 646                         atomic_inc(&dev->parent->power.child_count);
 647                         spin_unlock(&dev->parent->power.lock);
 648                         goto no_callback;       /* Assume success. */
 649                 }
 650                 spin_unlock(&dev->parent->power.lock);
 651         }
 652
 653         /* Carry out an asynchronous or a synchronous resume. */
 654         if (rpmflags & RPM_ASYNC) {
 655                 dev->power.request = RPM_REQ_RESUME;
 656                 if (!dev->power.request_pending) {
 657                         dev->power.request_pending = true;
 658                         queue_work(pm_wq, &dev->power.work);
 659                 }
 660                 retval = 0;
 661                 goto out;
 662         }
 663
 664         if (!parent && dev->parent) {
 665                 /*
 666                  * Increment the parent's usage counter and resume it if
 667                  * necessary.  Not needed if dev is irq-safe; then the
 668                  * parent is permanently resumed.
 669                  */
 670                 parent = dev->parent;
 671                 if (dev->power.irq_safe)
 672                         goto skip_parent;
 673                 spin_unlock(&dev->power.lock);
 674
 675                 pm_runtime_get_noresume(parent);
 676
 677                 spin_lock(&parent->power.lock);
 678                 /*
 679                  * We can resume if the parent's runtime PM is disabled or it
 680                  * is set to ignore children.
 681                  */
 682                 if (!parent->power.disable_depth
 683                     && !parent->power.ignore_children) {
 684                         rpm_resume(parent, 0);
 685                         if (parent->power.runtime_status != RPM_ACTIVE)
 686                                 retval = -EBUSY;
 687                 }
 688                 spin_unlock(&parent->power.lock);
 689
 690                 spin_lock(&dev->power.lock);
 691                 if (retval)
 692                         goto out;
 693                 goto repeat;
 694         }
 695  skip_parent:
 696
 697         if (dev->power.no_callbacks)
 698                 goto no_callback;       /* Assume success. */
 699
 700         dev->power.suspend_time = ktime_set(0, 0);
 701         dev->power.max_time_suspended_ns = -1;
 702
 703         __update_runtime_status(dev, RPM_RESUMING);
 704
 705         if (dev->pm_domain)
 706                 callback = dev->pm_domain->ops.runtime_resume;
 707         else if (dev->type && dev->type->pm)
 708                 callback = dev->type->pm->runtime_resume;
 709         else if (dev->class && dev->class->pm)
 710                 callback = dev->class->pm->runtime_resume;
 711         else if (dev->bus && dev->bus->pm)
 712                 callback = dev->bus->pm->runtime_resume;
 713         else
 714                 callback = NULL;
 715
 716         retval = rpm_callback(callback, dev);
 717         if (retval) {
 718                 __update_runtime_status(dev, RPM_SUSPENDED);
 719                 pm_runtime_cancel_pending(dev);
 720         } else {
 721  no_callback:
 722                 __update_runtime_status(dev, RPM_ACTIVE);
 723                 if (parent)
 724                         atomic_inc(&parent->power.child_count);
 725         }
 726         wake_up_all(&dev->power.wait_queue);
 727
 728         if (!retval)
 729                 rpm_idle(dev, RPM_ASYNC);
 730
 731  out:
 732         if (parent && !dev->power.irq_safe) {
 733                 spin_unlock_irq(&dev->power.lock);
 734
 735                 pm_runtime_put(parent);
 736
 737                 spin_lock_irq(&dev->power.lock);
 738         }
 739
 740         trace_rpm_return_int(dev, _THIS_IP_, retval);
 741
 742         return retval;
 743 }
 744
 745 /**
 746  * pm_runtime_work - Universal runtime PM work function.
 747  * @work: Work structure used for scheduling the execution of this function.
 748  *
 749  * Use @work to get the device object the work is to be done for, determine what
 750  * is to be done and execute the appropriate runtime PM function.
 751  */
 752 static void pm_runtime_work(struct work_struct *work)
 753 {
 754         struct device *dev = container_of(work, struct device, power.work);
 755         enum rpm_request req;
 756
 757         spin_lock_irq(&dev->power.lock);
 758
 759         if (!dev->power.request_pending)
 760                 goto out;
 761
 762         req = dev->power.request;
 763         dev->power.request = RPM_REQ_NONE;
 764         dev->power.request_pending = false;
 765
 766         switch (req) {
 767         case RPM_REQ_NONE:
 768                 break;
 769         case RPM_REQ_IDLE:
 770                 rpm_idle(dev, RPM_NOWAIT);
 771                 break;
 772         case RPM_REQ_SUSPEND:
 773                 rpm_suspend(dev, RPM_NOWAIT);
 774                 break;
 775         case RPM_REQ_AUTOSUSPEND:
 776                 rpm_suspend(dev, RPM_NOWAIT | RPM_AUTO);
 777                 break;
 778         case RPM_REQ_RESUME:
 779                 rpm_resume(dev, RPM_NOWAIT);
 780                 break;
 781         }
 782
 783  out:
 784         spin_unlock_irq(&dev->power.lock);
 785 }
 786
 787 /**
 788  * pm_suspend_timer_fn - Timer function for pm_schedule_suspend().
 789  * @data: Device pointer passed by pm_schedule_suspend().
 790  *
 791  * Check if the time is right and queue a suspend request.
 792  */
 793 static void pm_suspend_timer_fn(unsigned long data)
 794 {
 795         struct device *dev = (struct device *)data;
 796         unsigned long flags;
 797         unsigned long expires;
 798
 799         spin_lock_irqsave(&dev->power.lock, flags);
 800
 801         expires = dev->power.timer_expires;
 802         /* If 'expire' is after 'jiffies' we've been called too early. */
 803         if (expires > 0 && !time_after(expires, jiffies)) {
 804                 dev->power.timer_expires = 0;
 805                 rpm_suspend(dev, dev->power.timer_autosuspends ?
 806                     (RPM_ASYNC | RPM_AUTO) : RPM_ASYNC);
 807         }
 808
 809         spin_unlock_irqrestore(&dev->power.lock, flags);
 810 }
 811
 812 /**
 813  * pm_schedule_suspend - Set up a timer to submit a suspend request in future.
 814  * @dev: Device to suspend.
 815  * @delay: Time to wait before submitting a suspend request, in milliseconds.
 816  */
 817 int pm_schedule_suspend(struct device *dev, unsigned int delay)
 818 {
 819         unsigned long flags;
 820         int retval;
 821
 822         spin_lock_irqsave(&dev->power.lock, flags);
 823
 824         if (!delay) {
 825                 retval = rpm_suspend(dev, RPM_ASYNC);
 826                 goto out;
 827         }
 828
 829         retval = rpm_check_suspend_allowed(dev);
 830         if (retval)
 831                 goto out;
 832
 833         /* Other scheduled or pending requests need to be canceled. */
 834         pm_runtime_cancel_pending(dev);
 835
 836         dev->power.timer_expires = jiffies + msecs_to_jiffies(delay);
 837         dev->power.timer_expires += !dev->power.timer_expires;
 838         dev->power.timer_autosuspends = 0;
 839         mod_timer(&dev->power.suspend_timer, dev->power.timer_expires);
 840
 841  out:
 842         spin_unlock_irqrestore(&dev->power.lock, flags);
 843
 844         return retval;
 845 }
 846 EXPORT_SYMBOL_GPL(pm_schedule_suspend);
 847
 848 /**
 849  * __pm_runtime_idle - Entry point for runtime idle operations.
 850  * @dev: Device to send idle notification for.
 851  * @rpmflags: Flag bits.
 852  *
 853  * If the RPM_GET_PUT flag is set, decrement the device's usage count and
 854  * return immediately if it is larger than zero.  Then carry out an idle
 855  * notification, either synchronous or asynchronous.
 856  *
 857  * This routine may be called in atomic context if the RPM_ASYNC flag is set,
 858  * or if pm_runtime_irq_safe() has been called.
 859  */
 860 int __pm_runtime_idle(struct device *dev, int rpmflags)
 861 {
 862         unsigned long flags;
 863         int retval;
 864
 865         might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe);
 866
 867         if (rpmflags & RPM_GET_PUT) {
 868                 if (!atomic_dec_and_test(&dev->power.usage_count))
 869                         return 0;
 870         }
 871
 872         spin_lock_irqsave(&dev->power.lock, flags);
 873         retval = rpm_idle(dev, rpmflags);
 874         spin_unlock_irqrestore(&dev->power.lock, flags);
 875
 876         return retval;
 877 }
 878 EXPORT_SYMBOL_GPL(__pm_runtime_idle);
 879
 880 /**
 881  * __pm_runtime_suspend - Entry point for runtime put/suspend operations.
 882  * @dev: Device to suspend.
 883  * @rpmflags: Flag bits.
 884  *
 885  * If the RPM_GET_PUT flag is set, decrement the device's usage count and
 886  * return immediately if it is larger than zero.  Then carry out a suspend,
 887  * either synchronous or asynchronous.
 888  *
 889  * This routine may be called in atomic context if the RPM_ASYNC flag is set,
 890  * or if pm_runtime_irq_safe() has been called.
 891  */
 892 int __pm_runtime_suspend(struct device *dev, int rpmflags)
 893 {
 894         unsigned long flags;
 895         int retval;
 896
 897         might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe);
 898
 899         if (rpmflags & RPM_GET_PUT) {
 900                 if (!atomic_dec_and_test(&dev->power.usage_count))
 901                         return 0;
 902         }
 903
 904         spin_lock_irqsave(&dev->power.lock, flags);
 905         retval = rpm_suspend(dev, rpmflags);
 906         spin_unlock_irqrestore(&dev->power.lock, flags);
 907
 908         return retval;
 909 }
 910 EXPORT_SYMBOL_GPL(__pm_runtime_suspend);
 911
 912 /**
 913  * __pm_runtime_resume - Entry point for runtime resume operations.
 914  * @dev: Device to resume.
 915  * @rpmflags: Flag bits.
 916  *
 917  * If the RPM_GET_PUT flag is set, increment the device's usage count.  Then
 918  * carry out a resume, either synchronous or asynchronous.
 919  *
 920  * This routine may be called in atomic context if the RPM_ASYNC flag is set,
 921  * or if pm_runtime_irq_safe() has been called.
 922  */
 923 int __pm_runtime_resume(struct device *dev, int rpmflags)
 924 {
 925         unsigned long flags;
 926         int retval;
 927
 928         might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe);
 929
 930         if (rpmflags & RPM_GET_PUT)
 931                 atomic_inc(&dev->power.usage_count);
 932
 933         spin_lock_irqsave(&dev->power.lock, flags);
 934         retval = rpm_resume(dev, rpmflags);
 935         spin_unlock_irqrestore(&dev->power.lock, flags);
 936
 937         return retval;
 938 }
 939 EXPORT_SYMBOL_GPL(__pm_runtime_resume);
 940
 941 /**
 942  * __pm_runtime_set_status - Set runtime PM status of a device.
 943  * @dev: Device to handle.
 944  * @status: New runtime PM status of the device.
 945  *
 946  * If runtime PM of the device is disabled or its power.runtime_error field is
 947  * different from zero, the status may be changed either to RPM_ACTIVE, or to
 948  * RPM_SUSPENDED, as long as that reflects the actual state of the device.
 949  * However, if the device has a parent and the parent is not active, and the
 950  * parent's power.ignore_children flag is unset, the device's status cannot be
 951  * set to RPM_ACTIVE, so -EBUSY is returned in that case.
 952  *
 953  * If successful, __pm_runtime_set_status() clears the power.runtime_error field
 954  * and the device parent's counter of unsuspended children is modified to
 955  * reflect the new status.  If the new status is RPM_SUSPENDED, an idle
 956  * notification request for the parent is submitted.
 957  */
 958 int __pm_runtime_set_status(struct device *dev, unsigned int status)
 959 {
 960         struct device *parent = dev->parent;
 961         unsigned long flags;
 962         bool notify_parent = false;
 963         int error = 0;
 964
 965         if (status != RPM_ACTIVE && status != RPM_SUSPENDED)
 966                 return -EINVAL;
 967
 968         spin_lock_irqsave(&dev->power.lock, flags);
 969
 970         if (!dev->power.runtime_error && !dev->power.disable_depth) {
 971                 error = -EAGAIN;
 972                 goto out;
 973         }
 974
 975         if (dev->power.runtime_status == status)
 976                 goto out_set;
 977
 978         if (status == RPM_SUSPENDED) {
 979                 /* It always is possible to set the status to 'suspended'. */
 980                 if (parent) {
 981                         atomic_add_unless(&parent->power.child_count, -1, 0);
 982                         notify_parent = !parent->power.ignore_children;
 983                 }
 984                 goto out_set;
 985         }
 986
 987         if (parent) {
 988                 spin_lock_nested(&parent->power.lock, SINGLE_DEPTH_NESTING);
 989
 990                 /*
 991                  * It is invalid to put an active child under a parent that is
 992                  * not active, has runtime PM enabled and the
 993                  * 'power.ignore_children' flag unset.
 994                  */
 995                 if (!parent->power.disable_depth
 996                     && !parent->power.ignore_children
 997                     && parent->power.runtime_status != RPM_ACTIVE)
 998                         error = -EBUSY;
 999                 else if (dev->power.runtime_status == RPM_SUSPENDED)
1000                         atomic_inc(&parent->power.child_count);
1001
1002                 spin_unlock(&parent->power.lock);
1003
1004                 if (error)
1005                         goto out;
1006         }
1007
1008  out_set:
1009         __update_runtime_status(dev, status);
1010         dev->power.runtime_error = 0;
1011  out:
1012         spin_unlock_irqrestore(&dev->power.lock, flags);
1013
1014         if (notify_parent)
1015                 pm_request_idle(parent);
1016
1017         return error;
1018 }
1019 EXPORT_SYMBOL_GPL(__pm_runtime_set_status);
1020
1021 /**
1022  * __pm_runtime_barrier - Cancel pending requests and wait for completions.
1023  * @dev: Device to handle.
1024  *
1025  * Flush all pending requests for the device from pm_wq and wait for all
1026  * runtime PM operations involving the device in progress to complete.
1027  *
1028  * Should be called under dev->power.lock with interrupts disabled.
1029  */
1030 static void __pm_runtime_barrier(struct device *dev)
1031 {
1032         pm_runtime_deactivate_timer(dev);
1033
1034         if (dev->power.request_pending) {
1035                 dev->power.request = RPM_REQ_NONE;
1036                 spin_unlock_irq(&dev->power.lock);
1037
1038                 cancel_work_sync(&dev->power.work);
1039
1040                 spin_lock_irq(&dev->power.lock);
1041                 dev->power.request_pending = false;
1042         }
1043
1044         if (dev->power.runtime_status == RPM_SUSPENDING
1045             || dev->power.runtime_status == RPM_RESUMING
1046             || dev->power.idle_notification) {
1047                 DEFINE_WAIT(wait);
1048
1049                 /* Suspend, wake-up or idle notification in progress. */
1050                 for (;;) {
1051                         prepare_to_wait(&dev->power.wait_queue, &wait,
1052                                         TASK_UNINTERRUPTIBLE);
1053                         if (dev->power.runtime_status != RPM_SUSPENDING
1054                             && dev->power.runtime_status != RPM_RESUMING
1055                             && !dev->power.idle_notification)
1056                                 break;
1057                         spin_unlock_irq(&dev->power.lock);
1058
1059                         schedule();
1060
1061                         spin_lock_irq(&dev->power.lock);
1062                 }
1063                 finish_wait(&dev->power.wait_queue, &wait);
1064         }
1065 }
1066
1067 /**
1068  * pm_runtime_barrier - Flush pending requests and wait for completions.
1069  * @dev: Device to handle.
1070  *
1071  * Prevent the device from being suspended by incrementing its usage counter and
1072  * if there's a pending resume request for the device, wake the device up.
1073  * Next, make sure that all pending requests for the device have been flushed
1074  * from pm_wq and wait for all runtime PM operations involving the device in
1075  * progress to complete.
1076  *
1077  * Return value:
1078  * 1, if there was a resume request pending and the device had to be woken up,
1079  * 0, otherwise
1080  */
1081 int pm_runtime_barrier(struct device *dev)
1082 {
1083         int retval = 0;
1084
1085         pm_runtime_get_noresume(dev);
1086         spin_lock_irq(&dev->power.lock);
1087
1088         if (dev->power.request_pending
1089             && dev->power.request == RPM_REQ_RESUME) {
1090                 rpm_resume(dev, 0);
1091                 retval = 1;
1092         }
1093
1094         __pm_runtime_barrier(dev);
1095
1096         spin_unlock_irq(&dev->power.lock);
1097         pm_runtime_put_noidle(dev);
1098
1099         return retval;
1100 }
1101 EXPORT_SYMBOL_GPL(pm_runtime_barrier);
1102
1103 /**
1104  * __pm_runtime_disable - Disable runtime PM of a device.
1105  * @dev: Device to handle.
1106  * @check_resume: If set, check if there's a resume request for the device.
1107  *
1108  * Increment power.disable_depth for the device and if was zero previously,
1109  * cancel all pending runtime PM requests for the device and wait for all
1110  * operations in progress to complete.  The device can be either active or
1111  * suspended after its runtime PM has been disabled.
1112  *
1113  * If @check_resume is set and there's a resume request pending when
1114  * __pm_runtime_disable() is called and power.disable_depth is zero, the
1115  * function will wake up the device before disabling its runtime PM.
1116  */
1117 void __pm_runtime_disable(struct device *dev, bool check_resume)
1118 {
1119         spin_lock_irq(&dev->power.lock);
1120
1121         if (dev->power.disable_depth > 0) {
1122                 dev->power.disable_depth++;
1123                 goto out;
1124         }
1125
1126         /*
1127          * Wake up the device if there's a resume request pending, because that
1128          * means there probably is some I/O to process and disabling runtime PM
1129          * shouldn't prevent the device from processing the I/O.
1130          */
1131         if (check_resume && dev->power.request_pending
1132             && dev->power.request == RPM_REQ_RESUME) {
1133                 /*
1134                  * Prevent suspends and idle notifications from being carried
1135                  * out after we have woken up the device.
1136                  */
1137                 pm_runtime_get_noresume(dev);
1138
1139                 rpm_resume(dev, 0);
1140
1141                 pm_runtime_put_noidle(dev);
1142         }
1143
1144         if (!dev->power.disable_depth++)
1145                 __pm_runtime_barrier(dev);
1146
1147  out:
1148         spin_unlock_irq(&dev->power.lock);
1149 }
1150 EXPORT_SYMBOL_GPL(__pm_runtime_disable);
1151
1152 /**
1153  * pm_runtime_enable - Enable runtime PM of a device.
1154  * @dev: Device to handle.
1155  */
1156 void pm_runtime_enable(struct device *dev)
1157 {
1158         unsigned long flags;
1159
1160         spin_lock_irqsave(&dev->power.lock, flags);
1161
1162         if (dev->power.disable_depth > 0)
1163                 dev->power.disable_depth--;
1164         else
1165                 dev_warn(dev, "Unbalanced %s!\n", __func__);
1166
1167         spin_unlock_irqrestore(&dev->power.lock, flags);
1168 }
1169 EXPORT_SYMBOL_GPL(pm_runtime_enable);
1170
1171 /**
1172  * pm_runtime_forbid - Block runtime PM of a device.
1173  * @dev: Device to handle.
1174  *
1175  * Increase the device's usage count and clear its power.runtime_auto flag,
1176  * so that it cannot be suspended at run time until pm_runtime_allow() is called
1177  * for it.
1178  */
1179 void pm_runtime_forbid(struct device *dev)
1180 {
1181         spin_lock_irq(&dev->power.lock);
1182         if (!dev->power.runtime_auto)
1183                 goto out;
1184
1185         dev->power.runtime_auto = false;
1186         atomic_inc(&dev->power.usage_count);
1187         rpm_resume(dev, 0);
1188
1189  out:
1190         spin_unlock_irq(&dev->power.lock);
1191 }
1192 EXPORT_SYMBOL_GPL(pm_runtime_forbid);
1193
1194 /**
1195  * pm_runtime_allow - Unblock runtime PM of a device.
1196  * @dev: Device to handle.
1197  *
1198  * Decrease the device's usage count and set its power.runtime_auto flag.
1199  */
1200 void pm_runtime_allow(struct device *dev)
1201 {
1202         spin_lock_irq(&dev->power.lock);
1203         if (dev->power.runtime_auto)
1204                 goto out;
1205
1206         dev->power.runtime_auto = true;
1207         if (atomic_dec_and_test(&dev->power.usage_count))
1208                 rpm_idle(dev, RPM_AUTO);
1209
1210  out:
1211         spin_unlock_irq(&dev->power.lock);
1212 }
1213 EXPORT_SYMBOL_GPL(pm_runtime_allow);
1214
1215 /**
1216  * pm_runtime_no_callbacks - Ignore runtime PM callbacks for a device.
1217  * @dev: Device to handle.
1218  *
1219  * Set the power.no_callbacks flag, which tells the PM core that this
1220  * device is power-managed through its parent and has no runtime PM
1221  * callbacks of its own.  The runtime sysfs attributes will be removed.
1222  */
1223 void pm_runtime_no_callbacks(struct device *dev)
1224 {
1225         spin_lock_irq(&dev->power.lock);
1226         dev->power.no_callbacks = 1;
1227         spin_unlock_irq(&dev->power.lock);
1228         if (device_is_registered(dev))
1229                 rpm_sysfs_remove(dev);
1230 }
1231 EXPORT_SYMBOL_GPL(pm_runtime_no_callbacks);
1232
1233 /**
1234  * pm_runtime_irq_safe - Leave interrupts disabled during callbacks.
1235  * @dev: Device to handle
1236  *
1237  * Set the power.irq_safe flag, which tells the PM core that the
1238  * ->runtime_suspend() and ->runtime_resume() callbacks for this device should
1239  * always be invoked with the spinlock held and interrupts disabled.  It also
1240  * causes the parent's usage counter to be permanently incremented, preventing
1241  * the parent from runtime suspending -- otherwise an irq-safe child might have
1242  * to wait for a non-irq-safe parent.
1243  */
1244 void pm_runtime_irq_safe(struct device *dev)
1245 {
1246         if (dev->parent)
1247                 pm_runtime_get_sync(dev->parent);
1248         spin_lock_irq(&dev->power.lock);
1249         dev->power.irq_safe = 1;
1250         spin_unlock_irq(&dev->power.lock);
1251 }
1252 EXPORT_SYMBOL_GPL(pm_runtime_irq_safe);
1253
1254 /**
1255  * update_autosuspend - Handle a change to a device's autosuspend settings.
1256  * @dev: Device to handle.
1257  * @old_delay: The former autosuspend_delay value.
1258  * @old_use: The former use_autosuspend value.
1259  *
1260  * Prevent runtime suspend if the new delay is negative and use_autosuspend is
1261  * set; otherwise allow it.  Send an idle notification if suspends are allowed.
1262  *
1263  * This function must be called under dev->power.lock with interrupts disabled.
1264  */
1265 static void update_autosuspend(struct device *dev, int old_delay, int old_use)
1266 {
1267         int delay = dev->power.autosuspend_delay;
1268
1269         /* Should runtime suspend be prevented now? */
1270         if (dev->power.use_autosuspend && delay < 0) {
1271
1272                 /* If it used to be allowed then prevent it. */
1273                 if (!old_use || old_delay >= 0) {
1274                         atomic_inc(&dev->power.usage_count);
1275                         rpm_resume(dev, 0);
1276                 }
1277         }
1278
1279         /* Runtime suspend should be allowed now. */
1280         else {
1281
1282                 /* If it used to be prevented then allow it. */
1283                 if (old_use && old_delay < 0)
1284                         atomic_dec(&dev->power.usage_count);
1285
1286                 /* Maybe we can autosuspend now. */
1287                 rpm_idle(dev, RPM_AUTO);
1288         }
1289 }
1290
1291 /**
1292  * pm_runtime_set_autosuspend_delay - Set a device's autosuspend_delay value.
1293  * @dev: Device to handle.
1294  * @delay: Value of the new delay in milliseconds.
1295  *
1296  * Set the device's power.autosuspend_delay value.  If it changes to negative
1297  * and the power.use_autosuspend flag is set, prevent runtime suspends.  If it
1298  * changes the other way, allow runtime suspends.
1299  */
1300 void pm_runtime_set_autosuspend_delay(struct device *dev, int delay)
1301 {
1302         int old_delay, old_use;
1303
1304         spin_lock_irq(&dev->power.lock);
1305         old_delay = dev->power.autosuspend_delay;
1306         old_use = dev->power.use_autosuspend;
1307         dev->power.autosuspend_delay = delay;
1308         update_autosuspend(dev, old_delay, old_use);
1309         spin_unlock_irq(&dev->power.lock);
1310 }
1311 EXPORT_SYMBOL_GPL(pm_runtime_set_autosuspend_delay);
1312
1313 /**
1314  * __pm_runtime_use_autosuspend - Set a device's use_autosuspend flag.
1315  * @dev: Device to handle.
1316  * @use: New value for use_autosuspend.
1317  *
1318  * Set the device's power.use_autosuspend flag, and allow or prevent runtime
1319  * suspends as needed.
1320  */
1321 void __pm_runtime_use_autosuspend(struct device *dev, bool use)
1322 {
1323         int old_delay, old_use;
1324
1325         spin_lock_irq(&dev->power.lock);
1326         old_delay = dev->power.autosuspend_delay;
1327         old_use = dev->power.use_autosuspend;
1328         dev->power.use_autosuspend = use;
1329         update_autosuspend(dev, old_delay, old_use);
1330         spin_unlock_irq(&dev->power.lock);
1331 }
1332 EXPORT_SYMBOL_GPL(__pm_runtime_use_autosuspend);
1333
1334 /**
1335  * pm_runtime_init - Initialize runtime PM fields in given device object.
1336  * @dev: Device object to initialize.
1337  */
1338 void pm_runtime_init(struct device *dev)
1339 {
1340         dev->power.runtime_status = RPM_SUSPENDED;
1341         dev->power.idle_notification = false;
1342
1343         dev->power.disable_depth = 1;
1344         atomic_set(&dev->power.usage_count, 0);
1345
1346         dev->power.runtime_error = 0;
1347
1348         atomic_set(&dev->power.child_count, 0);
1349         pm_suspend_ignore_children(dev, false);
1350         dev->power.runtime_auto = true;
1351
1352         dev->power.request_pending = false;
1353         dev->power.request = RPM_REQ_NONE;
1354         dev->power.deferred_resume = false;
1355         dev->power.accounting_timestamp = jiffies;
1356         INIT_WORK(&dev->power.work, pm_runtime_work);
1357
1358         dev->power.timer_expires = 0;
1359         setup_timer(&dev->power.suspend_timer, pm_suspend_timer_fn,
1360                         (unsigned long)dev);
1361
1362         dev->power.suspend_time = ktime_set(0, 0);
1363         dev->power.max_time_suspended_ns = -1;
1364
1365         init_waitqueue_head(&dev->power.wait_queue);
1366 }
1367
1368 /**
1369  * pm_runtime_remove - Prepare for removing a device from device hierarchy.
1370  * @dev: Device object being removed from device hierarchy.
1371  */
1372 void pm_runtime_remove(struct device *dev)
1373 {
1374         __pm_runtime_disable(dev, false);
1375
1376         /* Change the status back to 'suspended' to match the initial status. */
1377         if (dev->power.runtime_status == RPM_ACTIVE)
1378                 pm_runtime_set_suspended(dev);
1379         if (dev->power.irq_safe && dev->parent)
1380                 pm_runtime_put_sync(dev->parent);
1381 }
1382
1383 /**
1384  * pm_runtime_update_max_time_suspended - Update device's suspend time data.
1385  * @dev: Device to handle.
1386  * @delta_ns: Value to subtract from the device's max_time_suspended_ns field.
1387  *
1388  * Update the device's power.max_time_suspended_ns field by subtracting
1389  * @delta_ns from it.  The resulting value of power.max_time_suspended_ns is
1390  * never negative.
1391  */
1392 void pm_runtime_update_max_time_suspended(struct device *dev, s64 delta_ns)
1393 {
1394         unsigned long flags;
1395
1396         spin_lock_irqsave(&dev->power.lock, flags);
1397
1398         if (delta_ns > 0 && dev->power.max_time_suspended_ns > 0) {
1399                 if (dev->power.max_time_suspended_ns > delta_ns)
1400                         dev->power.max_time_suspended_ns -= delta_ns;
1401                 else
1402                         dev->power.max_time_suspended_ns = 0;
1403         }
1404
1405         spin_unlock_irqrestore(&dev->power.lock, flags);
1406 }