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 && dev->driver && dev->driver->pm)
 254                 callback = dev->driver->pm->runtime_idle;
 255
 256         if (callback)
 257                 __rpm_callback(callback, dev);
 258
 259         dev->power.idle_notification = false;
 260         wake_up_all(&dev->power.wait_queue);
 261
 262  out:
 263         trace_rpm_return_int(dev, _THIS_IP_, retval);
 264         return retval;
 265 }
 266
 267 /**
 268  * rpm_callback - Run a given runtime PM callback for a given device.
 269  * @cb: Runtime PM callback to run.
 270  * @dev: Device to run the callback for.
 271  */
 272 static int rpm_callback(int (*cb)(struct device *), struct device *dev)
 273 {
 274         int retval;
 275
 276         if (!cb)
 277                 return -ENOSYS;
 278
 279         retval = __rpm_callback(cb, dev);
 280
 281         dev->power.runtime_error = retval;
 282         return retval != -EACCES ? retval : -EIO;
 283 }
 284
 285 struct rpm_qos_data {
 286         ktime_t time_now;
 287         s64 constraint_ns;
 288 };
 289
 290 /**
 291  * rpm_update_qos_constraint - Update a given PM QoS constraint data.
 292  * @dev: Device whose timing data to use.
 293  * @data: PM QoS constraint data to update.
 294  *
 295  * Use the suspend timing data of @dev to update PM QoS constraint data pointed
 296  * to by @data.
 297  */
 298 static int rpm_update_qos_constraint(struct device *dev, void *data)
 299 {
 300         struct rpm_qos_data *qos = data;
 301         unsigned long flags;
 302         s64 delta_ns;
 303         int ret = 0;
 304
 305         spin_lock_irqsave(&dev->power.lock, flags);
 306
 307         if (dev->power.max_time_suspended_ns < 0)
 308                 goto out;
 309
 310         delta_ns = dev->power.max_time_suspended_ns -
 311                 ktime_to_ns(ktime_sub(qos->time_now, dev->power.suspend_time));
 312         if (delta_ns <= 0) {
 313                 ret = -EBUSY;
 314                 goto out;
 315         }
 316
 317         if (qos->constraint_ns > delta_ns || qos->constraint_ns == 0)
 318                 qos->constraint_ns = delta_ns;
 319
 320  out:
 321         spin_unlock_irqrestore(&dev->power.lock, flags);
 322
 323         return ret;
 324 }
 325
 326 /**
 327  * rpm_suspend - Carry out runtime suspend of given device.
 328  * @dev: Device to suspend.
 329  * @rpmflags: Flag bits.
 330  *
 331  * Check if the device's runtime PM status allows it to be suspended.
 332  * Cancel a pending idle notification, autosuspend or suspend. If
 333  * another suspend has been started earlier, either return immediately
 334  * or wait for it to finish, depending on the RPM_NOWAIT and RPM_ASYNC
 335  * flags. If the RPM_ASYNC flag is set then queue a suspend request;
 336  * otherwise run the ->runtime_suspend() callback directly. When
 337  * ->runtime_suspend succeeded, if a deferred resume was requested while
 338  * the callback was running then carry it out, otherwise send an idle
 339  * notification for its parent (if the suspend succeeded and both
 340  * ignore_children of parent->power and irq_safe of dev->power are not set).
 341  * If ->runtime_suspend failed with -EAGAIN or -EBUSY, and if the RPM_AUTO
 342  * flag is set and the next autosuspend-delay expiration time is in the
 343  * future, schedule another autosuspend attempt.
 344  *
 345  * This function must be called under dev->power.lock with interrupts disabled.
 346  */
 347 static int rpm_suspend(struct device *dev, int rpmflags)
 348         __releases(&dev->power.lock) __acquires(&dev->power.lock)
 349 {
 350         int (*callback)(struct device *);
 351         struct device *parent = NULL;
 352         struct rpm_qos_data qos;
 353         int retval;
 354
 355         trace_rpm_suspend(dev, rpmflags);
 356
 357  repeat:
 358         retval = rpm_check_suspend_allowed(dev);
 359
 360         if (retval < 0)
 361                 ;       /* Conditions are wrong. */
 362
 363         /* Synchronous suspends are not allowed in the RPM_RESUMING state. */
 364         else if (dev->power.runtime_status == RPM_RESUMING &&
 365             !(rpmflags & RPM_ASYNC))
 366                 retval = -EAGAIN;
 367         if (retval)
 368                 goto out;
 369
 370         /* If the autosuspend_delay time hasn't expired yet, reschedule. */
 371         if ((rpmflags & RPM_AUTO)
 372             && dev->power.runtime_status != RPM_SUSPENDING) {
 373                 unsigned long expires = pm_runtime_autosuspend_expiration(dev);
 374
 375                 if (expires != 0) {
 376                         /* Pending requests need to be canceled. */
 377                         dev->power.request = RPM_REQ_NONE;
 378
 379                         /*
 380                          * Optimization: If the timer is already running and is
 381                          * set to expire at or before the autosuspend delay,
 382                          * avoid the overhead of resetting it.  Just let it
 383                          * expire; pm_suspend_timer_fn() will take care of the
 384                          * rest.
 385                          */
 386                         if (!(dev->power.timer_expires && time_before_eq(
 387                             dev->power.timer_expires, expires))) {
 388                                 dev->power.timer_expires = expires;
 389                                 mod_timer(&dev->power.suspend_timer, expires);
 390                         }
 391                         dev->power.timer_autosuspends = 1;
 392                         goto out;
 393                 }
 394         }
 395
 396         /* Other scheduled or pending requests need to be canceled. */
 397         pm_runtime_cancel_pending(dev);
 398
 399         if (dev->power.runtime_status == RPM_SUSPENDING) {
 400                 DEFINE_WAIT(wait);
 401
 402                 if (rpmflags & (RPM_ASYNC | RPM_NOWAIT)) {
 403                         retval = -EINPROGRESS;
 404                         goto out;
 405                 }
 406
 407                 if (dev->power.irq_safe) {
 408                         spin_unlock(&dev->power.lock);
 409
 410                         cpu_relax();
 411
 412                         spin_lock(&dev->power.lock);
 413                         goto repeat;
 414                 }
 415
 416                 /* Wait for the other suspend running in parallel with us. */
 417                 for (;;) {
 418                         prepare_to_wait(&dev->power.wait_queue, &wait,
 419                                         TASK_UNINTERRUPTIBLE);
 420                         if (dev->power.runtime_status != RPM_SUSPENDING)
 421                                 break;
 422
 423                         spin_unlock_irq(&dev->power.lock);
 424
 425                         schedule();
 426
 427                         spin_lock_irq(&dev->power.lock);
 428                 }
 429                 finish_wait(&dev->power.wait_queue, &wait);
 430                 goto repeat;
 431         }
 432
 433         dev->power.deferred_resume = false;
 434         if (dev->power.no_callbacks)
 435                 goto no_callback;       /* Assume success. */
 436
 437         /* Carry out an asynchronous or a synchronous suspend. */
 438         if (rpmflags & RPM_ASYNC) {
 439                 dev->power.request = (rpmflags & RPM_AUTO) ?
 440                     RPM_REQ_AUTOSUSPEND : RPM_REQ_SUSPEND;
 441                 if (!dev->power.request_pending) {
 442                         dev->power.request_pending = true;
 443                         queue_work(pm_wq, &dev->power.work);
 444                 }
 445                 goto out;
 446         }
 447
 448         qos.constraint_ns = __dev_pm_qos_read_value(dev);
 449         if (qos.constraint_ns < 0) {
 450                 /* Negative constraint means "never suspend". */
 451                 retval = -EPERM;
 452                 goto out;
 453         }
 454         qos.constraint_ns *= NSEC_PER_USEC;
 455         qos.time_now = ktime_get();
 456
 457         __update_runtime_status(dev, RPM_SUSPENDING);
 458
 459         if (!dev->power.ignore_children) {
 460                 if (dev->power.irq_safe)
 461                         spin_unlock(&dev->power.lock);
 462                 else
 463                         spin_unlock_irq(&dev->power.lock);
 464
 465                 retval = device_for_each_child(dev, &qos,
 466                                                rpm_update_qos_constraint);
 467
 468                 if (dev->power.irq_safe)
 469                         spin_lock(&dev->power.lock);
 470                 else
 471                         spin_lock_irq(&dev->power.lock);
 472
 473                 if (retval)
 474                         goto fail;
 475         }
 476
 477         dev->power.suspend_time = qos.time_now;
 478         dev->power.max_time_suspended_ns = qos.constraint_ns ? : -1;
 479
 480         if (dev->pm_domain)
 481                 callback = dev->pm_domain->ops.runtime_suspend;
 482         else if (dev->type && dev->type->pm)
 483                 callback = dev->type->pm->runtime_suspend;
 484         else if (dev->class && dev->class->pm)
 485                 callback = dev->class->pm->runtime_suspend;
 486         else if (dev->bus && dev->bus->pm)
 487                 callback = dev->bus->pm->runtime_suspend;
 488         else
 489                 callback = NULL;
 490
 491         if (!callback && dev->driver && dev->driver->pm)
 492                 callback = dev->driver->pm->runtime_suspend;
 493
 494         retval = rpm_callback(callback, dev);
 495         if (retval)
 496                 goto fail;
 497
 498  no_callback:
 499         __update_runtime_status(dev, RPM_SUSPENDED);
 500         pm_runtime_deactivate_timer(dev);
 501
 502         if (dev->parent) {
 503                 parent = dev->parent;
 504                 atomic_add_unless(&parent->power.child_count, -1, 0);
 505         }
 506         wake_up_all(&dev->power.wait_queue);
 507
 508         if (dev->power.deferred_resume) {
 509                 rpm_resume(dev, 0);
 510                 retval = -EAGAIN;
 511                 goto out;
 512         }
 513
 514         /* Maybe the parent is now able to suspend. */
 515         if (parent && !parent->power.ignore_children && !dev->power.irq_safe) {
 516                 spin_unlock(&dev->power.lock);
 517
 518                 spin_lock(&parent->power.lock);
 519                 rpm_idle(parent, RPM_ASYNC);
 520                 spin_unlock(&parent->power.lock);
 521
 522                 spin_lock(&dev->power.lock);
 523         }
 524
 525  out:
 526         trace_rpm_return_int(dev, _THIS_IP_, retval);
 527
 528         return retval;
 529
 530  fail:
 531         __update_runtime_status(dev, RPM_ACTIVE);
 532         dev->power.suspend_time = ktime_set(0, 0);
 533         dev->power.max_time_suspended_ns = -1;
 534         dev->power.deferred_resume = false;
 535         if (retval == -EAGAIN || retval == -EBUSY) {
 536                 dev->power.runtime_error = 0;
 537
 538                 /*
 539                  * If the callback routine failed an autosuspend, and
 540                  * if the last_busy time has been updated so that there
 541                  * is a new autosuspend expiration time, automatically
 542                  * reschedule another autosuspend.
 543                  */
 544                 if ((rpmflags & RPM_AUTO) &&
 545                     pm_runtime_autosuspend_expiration(dev) != 0)
 546                         goto repeat;
 547         } else {
 548                 pm_runtime_cancel_pending(dev);
 549         }
 550         wake_up_all(&dev->power.wait_queue);
 551         goto out;
 552 }
 553
 554 /**
 555  * rpm_resume - Carry out runtime resume of given device.
 556  * @dev: Device to resume.
 557  * @rpmflags: Flag bits.
 558  *
 559  * Check if the device's runtime PM status allows it to be resumed.  Cancel
 560  * any scheduled or pending requests.  If another resume has been started
 561  * earlier, either return immediately or wait for it to finish, depending on the
 562  * RPM_NOWAIT and RPM_ASYNC flags.  Similarly, if there's a suspend running in
 563  * parallel with this function, either tell the other process to resume after
 564  * suspending (deferred_resume) or wait for it to finish.  If the RPM_ASYNC
 565  * flag is set then queue a resume request; otherwise run the
 566  * ->runtime_resume() callback directly.  Queue an idle notification for the
 567  * device if the resume succeeded.
 568  *
 569  * This function must be called under dev->power.lock with interrupts disabled.
 570  */
 571 static int rpm_resume(struct device *dev, int rpmflags)
 572         __releases(&dev->power.lock) __acquires(&dev->power.lock)
 573 {
 574         int (*callback)(struct device *);
 575         struct device *parent = NULL;
 576         int retval = 0;
 577
 578         trace_rpm_resume(dev, rpmflags);
 579
 580  repeat:
 581         if (dev->power.runtime_error)
 582                 retval = -EINVAL;
 583         else if (dev->power.disable_depth > 0)
 584                 retval = -EACCES;
 585         if (retval)
 586                 goto out;
 587
 588         /*
 589          * Other scheduled or pending requests need to be canceled.  Small
 590          * optimization: If an autosuspend timer is running, leave it running
 591          * rather than cancelling it now only to restart it again in the near
 592          * future.
 593          */
 594         dev->power.request = RPM_REQ_NONE;
 595         if (!dev->power.timer_autosuspends)
 596                 pm_runtime_deactivate_timer(dev);
 597
 598         if (dev->power.runtime_status == RPM_ACTIVE) {
 599                 retval = 1;
 600                 goto out;
 601         }
 602
 603         if (dev->power.runtime_status == RPM_RESUMING
 604             || dev->power.runtime_status == RPM_SUSPENDING) {
 605                 DEFINE_WAIT(wait);
 606
 607                 if (rpmflags & (RPM_ASYNC | RPM_NOWAIT)) {
 608                         if (dev->power.runtime_status == RPM_SUSPENDING)
 609                                 dev->power.deferred_resume = true;
 610                         else
 611                                 retval = -EINPROGRESS;
 612                         goto out;
 613                 }
 614
 615                 if (dev->power.irq_safe) {
 616                         spin_unlock(&dev->power.lock);
 617
 618                         cpu_relax();
 619
 620                         spin_lock(&dev->power.lock);
 621                         goto repeat;
 622                 }
 623
 624                 /* Wait for the operation carried out in parallel with us. */
 625                 for (;;) {
 626                         prepare_to_wait(&dev->power.wait_queue, &wait,
 627                                         TASK_UNINTERRUPTIBLE);
 628                         if (dev->power.runtime_status != RPM_RESUMING
 629                             && dev->power.runtime_status != RPM_SUSPENDING)
 630                                 break;
 631
 632                         spin_unlock_irq(&dev->power.lock);
 633
 634                         schedule();
 635
 636                         spin_lock_irq(&dev->power.lock);
 637                 }
 638                 finish_wait(&dev->power.wait_queue, &wait);
 639                 goto repeat;
 640         }
 641
 642         /*
 643          * See if we can skip waking up the parent.  This is safe only if
 644          * power.no_callbacks is set, because otherwise we don't know whether
 645          * the resume will actually succeed.
 646          */
 647         if (dev->power.no_callbacks && !parent && dev->parent) {
 648                 spin_lock_nested(&dev->parent->power.lock, SINGLE_DEPTH_NESTING);
 649                 if (dev->parent->power.disable_depth > 0
 650                     || dev->parent->power.ignore_children
 651                     || dev->parent->power.runtime_status == RPM_ACTIVE) {
 652                         atomic_inc(&dev->parent->power.child_count);
 653                         spin_unlock(&dev->parent->power.lock);
 654                         goto no_callback;       /* Assume success. */
 655                 }
 656                 spin_unlock(&dev->parent->power.lock);
 657         }
 658
 659         /* Carry out an asynchronous or a synchronous resume. */
 660         if (rpmflags & RPM_ASYNC) {
 661                 dev->power.request = RPM_REQ_RESUME;
 662                 if (!dev->power.request_pending) {
 663                         dev->power.request_pending = true;
 664                         queue_work(pm_wq, &dev->power.work);
 665                 }
 666                 retval = 0;
 667                 goto out;
 668         }
 669
 670         if (!parent && dev->parent) {
 671                 /*
 672                  * Increment the parent's usage counter and resume it if
 673                  * necessary.  Not needed if dev is irq-safe; then the
 674                  * parent is permanently resumed.
 675                  */
 676                 parent = dev->parent;
 677                 if (dev->power.irq_safe)
 678                         goto skip_parent;
 679                 spin_unlock(&dev->power.lock);
 680
 681                 pm_runtime_get_noresume(parent);
 682
 683                 spin_lock(&parent->power.lock);
 684                 /*
 685                  * We can resume if the parent's runtime PM is disabled or it
 686                  * is set to ignore children.
 687                  */
 688                 if (!parent->power.disable_depth
 689                     && !parent->power.ignore_children) {
 690                         rpm_resume(parent, 0);
 691                         if (parent->power.runtime_status != RPM_ACTIVE)
 692                                 retval = -EBUSY;
 693                 }
 694                 spin_unlock(&parent->power.lock);
 695
 696                 spin_lock(&dev->power.lock);
 697                 if (retval)
 698                         goto out;
 699                 goto repeat;
 700         }
 701  skip_parent:
 702
 703         if (dev->power.no_callbacks)
 704                 goto no_callback;       /* Assume success. */
 705
 706         dev->power.suspend_time = ktime_set(0, 0);
 707         dev->power.max_time_suspended_ns = -1;
 708
 709         __update_runtime_status(dev, RPM_RESUMING);
 710
 711         if (dev->pm_domain)
 712                 callback = dev->pm_domain->ops.runtime_resume;
 713         else if (dev->type && dev->type->pm)
 714                 callback = dev->type->pm->runtime_resume;
 715         else if (dev->class && dev->class->pm)
 716                 callback = dev->class->pm->runtime_resume;
 717         else if (dev->bus && dev->bus->pm)
 718                 callback = dev->bus->pm->runtime_resume;
 719         else
 720                 callback = NULL;
 721
 722         if (!callback && dev->driver && dev->driver->pm)
 723                 callback = dev->driver->pm->runtime_resume;
 724
 725         retval = rpm_callback(callback, dev);
 726         if (retval) {
 727                 __update_runtime_status(dev, RPM_SUSPENDED);
 728                 pm_runtime_cancel_pending(dev);
 729         } else {
 730  no_callback:
 731                 __update_runtime_status(dev, RPM_ACTIVE);
 732                 if (parent)
 733                         atomic_inc(&parent->power.child_count);
 734         }
 735         wake_up_all(&dev->power.wait_queue);
 736
 737         if (!retval)
 738                 rpm_idle(dev, RPM_ASYNC);
 739
 740  out:
 741         if (parent && !dev->power.irq_safe) {
 742                 spin_unlock_irq(&dev->power.lock);
 743
 744                 pm_runtime_put(parent);
 745
 746                 spin_lock_irq(&dev->power.lock);
 747         }
 748
 749         trace_rpm_return_int(dev, _THIS_IP_, retval);
 750
 751         return retval;
 752 }
 753
 754 /**
 755  * pm_runtime_work - Universal runtime PM work function.
 756  * @work: Work structure used for scheduling the execution of this function.
 757  *
 758  * Use @work to get the device object the work is to be done for, determine what
 759  * is to be done and execute the appropriate runtime PM function.
 760  */
 761 static void pm_runtime_work(struct work_struct *work)
 762 {
 763         struct device *dev = container_of(work, struct device, power.work);
 764         enum rpm_request req;
 765
 766         spin_lock_irq(&dev->power.lock);
 767
 768         if (!dev->power.request_pending)
 769                 goto out;
 770
 771         req = dev->power.request;
 772         dev->power.request = RPM_REQ_NONE;
 773         dev->power.request_pending = false;
 774
 775         switch (req) {
 776         case RPM_REQ_NONE:
 777                 break;
 778         case RPM_REQ_IDLE:
 779                 rpm_idle(dev, RPM_NOWAIT);
 780                 break;
 781         case RPM_REQ_SUSPEND:
 782                 rpm_suspend(dev, RPM_NOWAIT);
 783                 break;
 784         case RPM_REQ_AUTOSUSPEND:
 785                 rpm_suspend(dev, RPM_NOWAIT | RPM_AUTO);
 786                 break;
 787         case RPM_REQ_RESUME:
 788                 rpm_resume(dev, RPM_NOWAIT);
 789                 break;
 790         }
 791
 792  out:
 793         spin_unlock_irq(&dev->power.lock);
 794 }
 795
 796 /**
 797  * pm_suspend_timer_fn - Timer function for pm_schedule_suspend().
 798  * @data: Device pointer passed by pm_schedule_suspend().
 799  *
 800  * Check if the time is right and queue a suspend request.
 801  */
 802 static void pm_suspend_timer_fn(unsigned long data)
 803 {
 804         struct device *dev = (struct device *)data;
 805         unsigned long flags;
 806         unsigned long expires;
 807
 808         spin_lock_irqsave(&dev->power.lock, flags);
 809
 810         expires = dev->power.timer_expires;
 811         /* If 'expire' is after 'jiffies' we've been called too early. */
 812         if (expires > 0 && !time_after(expires, jiffies)) {
 813                 dev->power.timer_expires = 0;
 814                 rpm_suspend(dev, dev->power.timer_autosuspends ?
 815                     (RPM_ASYNC | RPM_AUTO) : RPM_ASYNC);
 816         }
 817
 818         spin_unlock_irqrestore(&dev->power.lock, flags);
 819 }
 820
 821 /**
 822  * pm_schedule_suspend - Set up a timer to submit a suspend request in future.
 823  * @dev: Device to suspend.
 824  * @delay: Time to wait before submitting a suspend request, in milliseconds.
 825  */
 826 int pm_schedule_suspend(struct device *dev, unsigned int delay)
 827 {
 828         unsigned long flags;
 829         int retval;
 830
 831         spin_lock_irqsave(&dev->power.lock, flags);
 832
 833         if (!delay) {
 834                 retval = rpm_suspend(dev, RPM_ASYNC);
 835                 goto out;
 836         }
 837
 838         retval = rpm_check_suspend_allowed(dev);
 839         if (retval)
 840                 goto out;
 841
 842         /* Other scheduled or pending requests need to be canceled. */
 843         pm_runtime_cancel_pending(dev);
 844
 845         dev->power.timer_expires = jiffies + msecs_to_jiffies(delay);
 846         dev->power.timer_expires += !dev->power.timer_expires;
 847         dev->power.timer_autosuspends = 0;
 848         mod_timer(&dev->power.suspend_timer, dev->power.timer_expires);
 849
 850  out:
 851         spin_unlock_irqrestore(&dev->power.lock, flags);
 852
 853         return retval;
 854 }
 855 EXPORT_SYMBOL_GPL(pm_schedule_suspend);
 856
 857 /**
 858  * __pm_runtime_idle - Entry point for runtime idle operations.
 859  * @dev: Device to send idle notification for.
 860  * @rpmflags: Flag bits.
 861  *
 862  * If the RPM_GET_PUT flag is set, decrement the device's usage count and
 863  * return immediately if it is larger than zero.  Then carry out an idle
 864  * notification, either synchronous or asynchronous.
 865  *
 866  * This routine may be called in atomic context if the RPM_ASYNC flag is set,
 867  * or if pm_runtime_irq_safe() has been called.
 868  */
 869 int __pm_runtime_idle(struct device *dev, int rpmflags)
 870 {
 871         unsigned long flags;
 872         int retval;
 873
 874         might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe);
 875
 876         if (rpmflags & RPM_GET_PUT) {
 877                 if (!atomic_dec_and_test(&dev->power.usage_count))
 878                         return 0;
 879         }
 880
 881         spin_lock_irqsave(&dev->power.lock, flags);
 882         retval = rpm_idle(dev, rpmflags);
 883         spin_unlock_irqrestore(&dev->power.lock, flags);
 884
 885         return retval;
 886 }
 887 EXPORT_SYMBOL_GPL(__pm_runtime_idle);
 888
 889 /**
 890  * __pm_runtime_suspend - Entry point for runtime put/suspend operations.
 891  * @dev: Device to suspend.
 892  * @rpmflags: Flag bits.
 893  *
 894  * If the RPM_GET_PUT flag is set, decrement the device's usage count and
 895  * return immediately if it is larger than zero.  Then carry out a suspend,
 896  * either synchronous or asynchronous.
 897  *
 898  * This routine may be called in atomic context if the RPM_ASYNC flag is set,
 899  * or if pm_runtime_irq_safe() has been called.
 900  */
 901 int __pm_runtime_suspend(struct device *dev, int rpmflags)
 902 {
 903         unsigned long flags;
 904         int retval;
 905
 906         might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe);
 907
 908         if (rpmflags & RPM_GET_PUT) {
 909                 if (!atomic_dec_and_test(&dev->power.usage_count))
 910                         return 0;
 911         }
 912
 913         spin_lock_irqsave(&dev->power.lock, flags);
 914         retval = rpm_suspend(dev, rpmflags);
 915         spin_unlock_irqrestore(&dev->power.lock, flags);
 916
 917         return retval;
 918 }
 919 EXPORT_SYMBOL_GPL(__pm_runtime_suspend);
 920
 921 /**
 922  * __pm_runtime_resume - Entry point for runtime resume operations.
 923  * @dev: Device to resume.
 924  * @rpmflags: Flag bits.
 925  *
 926  * If the RPM_GET_PUT flag is set, increment the device's usage count.  Then
 927  * carry out a resume, either synchronous or asynchronous.
 928  *
 929  * This routine may be called in atomic context if the RPM_ASYNC flag is set,
 930  * or if pm_runtime_irq_safe() has been called.
 931  */
 932 int __pm_runtime_resume(struct device *dev, int rpmflags)
 933 {
 934         unsigned long flags;
 935         int retval;
 936
 937         might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe);
 938
 939         if (rpmflags & RPM_GET_PUT)
 940                 atomic_inc(&dev->power.usage_count);
 941
 942         spin_lock_irqsave(&dev->power.lock, flags);
 943         retval = rpm_resume(dev, rpmflags);
 944         spin_unlock_irqrestore(&dev->power.lock, flags);
 945
 946         return retval;
 947 }
 948 EXPORT_SYMBOL_GPL(__pm_runtime_resume);
 949
 950 /**
 951  * __pm_runtime_set_status - Set runtime PM status of a device.
 952  * @dev: Device to handle.
 953  * @status: New runtime PM status of the device.
 954  *
 955  * If runtime PM of the device is disabled or its power.runtime_error field is
 956  * different from zero, the status may be changed either to RPM_ACTIVE, or to
 957  * RPM_SUSPENDED, as long as that reflects the actual state of the device.
 958  * However, if the device has a parent and the parent is not active, and the
 959  * parent's power.ignore_children flag is unset, the device's status cannot be
 960  * set to RPM_ACTIVE, so -EBUSY is returned in that case.
 961  *
 962  * If successful, __pm_runtime_set_status() clears the power.runtime_error field
 963  * and the device parent's counter of unsuspended children is modified to
 964  * reflect the new status.  If the new status is RPM_SUSPENDED, an idle
 965  * notification request for the parent is submitted.
 966  */
 967 int __pm_runtime_set_status(struct device *dev, unsigned int status)
 968 {
 969         struct device *parent = dev->parent;
 970         unsigned long flags;
 971         bool notify_parent = false;
 972         int error = 0;
 973
 974         if (status != RPM_ACTIVE && status != RPM_SUSPENDED)
 975                 return -EINVAL;
 976
 977         spin_lock_irqsave(&dev->power.lock, flags);
 978
 979         if (!dev->power.runtime_error && !dev->power.disable_depth) {
 980                 error = -EAGAIN;
 981                 goto out;
 982         }
 983
 984         if (dev->power.runtime_status == status)
 985                 goto out_set;
 986
 987         if (status == RPM_SUSPENDED) {
 988                 /* It always is possible to set the status to 'suspended'. */
 989                 if (parent) {
 990                         atomic_add_unless(&parent->power.child_count, -1, 0);
 991                         notify_parent = !parent->power.ignore_children;
 992                 }
 993                 goto out_set;
 994         }
 995
 996         if (parent) {
 997                 spin_lock_nested(&parent->power.lock, SINGLE_DEPTH_NESTING);
 998
 999                 /*
1000                  * It is invalid to put an active child under a parent that is
1001                  * not active, has runtime PM enabled and the
1002                  * 'power.ignore_children' flag unset.
1003                  */
1004                 if (!parent->power.disable_depth
1005                     && !parent->power.ignore_children
1006                     && parent->power.runtime_status != RPM_ACTIVE)
1007                         error = -EBUSY;
1008                 else if (dev->power.runtime_status == RPM_SUSPENDED)
1009                         atomic_inc(&parent->power.child_count);
1010
1011                 spin_unlock(&parent->power.lock);
1012
1013                 if (error)
1014                         goto out;
1015         }
1016
1017  out_set:
1018         __update_runtime_status(dev, status);
1019         dev->power.runtime_error = 0;
1020  out:
1021         spin_unlock_irqrestore(&dev->power.lock, flags);
1022
1023         if (notify_parent)
1024                 pm_request_idle(parent);
1025
1026         return error;
1027 }
1028 EXPORT_SYMBOL_GPL(__pm_runtime_set_status);
1029
1030 /**
1031  * __pm_runtime_barrier - Cancel pending requests and wait for completions.
1032  * @dev: Device to handle.
1033  *
1034  * Flush all pending requests for the device from pm_wq and wait for all
1035  * runtime PM operations involving the device in progress to complete.
1036  *
1037  * Should be called under dev->power.lock with interrupts disabled.
1038  */
1039 static void __pm_runtime_barrier(struct device *dev)
1040 {
1041         pm_runtime_deactivate_timer(dev);
1042
1043         if (dev->power.request_pending) {
1044                 dev->power.request = RPM_REQ_NONE;
1045                 spin_unlock_irq(&dev->power.lock);
1046
1047                 cancel_work_sync(&dev->power.work);
1048
1049                 spin_lock_irq(&dev->power.lock);
1050                 dev->power.request_pending = false;
1051         }
1052
1053         if (dev->power.runtime_status == RPM_SUSPENDING
1054             || dev->power.runtime_status == RPM_RESUMING
1055             || dev->power.idle_notification) {
1056                 DEFINE_WAIT(wait);
1057
1058                 /* Suspend, wake-up or idle notification in progress. */
1059                 for (;;) {
1060                         prepare_to_wait(&dev->power.wait_queue, &wait,
1061                                         TASK_UNINTERRUPTIBLE);
1062                         if (dev->power.runtime_status != RPM_SUSPENDING
1063                             && dev->power.runtime_status != RPM_RESUMING
1064                             && !dev->power.idle_notification)
1065                                 break;
1066                         spin_unlock_irq(&dev->power.lock);
1067
1068                         schedule();
1069
1070                         spin_lock_irq(&dev->power.lock);
1071                 }
1072                 finish_wait(&dev->power.wait_queue, &wait);
1073         }
1074 }
1075
1076 /**
1077  * pm_runtime_barrier - Flush pending requests and wait for completions.
1078  * @dev: Device to handle.
1079  *
1080  * Prevent the device from being suspended by incrementing its usage counter and
1081  * if there's a pending resume request for the device, wake the device up.
1082  * Next, make sure that all pending requests for the device have been flushed
1083  * from pm_wq and wait for all runtime PM operations involving the device in
1084  * progress to complete.
1085  *
1086  * Return value:
1087  * 1, if there was a resume request pending and the device had to be woken up,
1088  * 0, otherwise
1089  */
1090 int pm_runtime_barrier(struct device *dev)
1091 {
1092         int retval = 0;
1093
1094         pm_runtime_get_noresume(dev);
1095         spin_lock_irq(&dev->power.lock);
1096
1097         if (dev->power.request_pending
1098             && dev->power.request == RPM_REQ_RESUME) {
1099                 rpm_resume(dev, 0);
1100                 retval = 1;
1101         }
1102
1103         __pm_runtime_barrier(dev);
1104
1105         spin_unlock_irq(&dev->power.lock);
1106         pm_runtime_put_noidle(dev);
1107
1108         return retval;
1109 }
1110 EXPORT_SYMBOL_GPL(pm_runtime_barrier);
1111
1112 /**
1113  * __pm_runtime_disable - Disable runtime PM of a device.
1114  * @dev: Device to handle.
1115  * @check_resume: If set, check if there's a resume request for the device.
1116  *
1117  * Increment power.disable_depth for the device and if was zero previously,
1118  * cancel all pending runtime PM requests for the device and wait for all
1119  * operations in progress to complete.  The device can be either active or
1120  * suspended after its runtime PM has been disabled.
1121  *
1122  * If @check_resume is set and there's a resume request pending when
1123  * __pm_runtime_disable() is called and power.disable_depth is zero, the
1124  * function will wake up the device before disabling its runtime PM.
1125  */
1126 void __pm_runtime_disable(struct device *dev, bool check_resume)
1127 {
1128         spin_lock_irq(&dev->power.lock);
1129
1130         if (dev->power.disable_depth > 0) {
1131                 dev->power.disable_depth++;
1132                 goto out;
1133         }
1134
1135         /*
1136          * Wake up the device if there's a resume request pending, because that
1137          * means there probably is some I/O to process and disabling runtime PM
1138          * shouldn't prevent the device from processing the I/O.
1139          */
1140         if (check_resume && dev->power.request_pending
1141             && dev->power.request == RPM_REQ_RESUME) {
1142                 /*
1143                  * Prevent suspends and idle notifications from being carried
1144                  * out after we have woken up the device.
1145                  */
1146                 pm_runtime_get_noresume(dev);
1147
1148                 rpm_resume(dev, 0);
1149
1150                 pm_runtime_put_noidle(dev);
1151         }
1152
1153         if (!dev->power.disable_depth++)
1154                 __pm_runtime_barrier(dev);
1155
1156  out:
1157         spin_unlock_irq(&dev->power.lock);
1158 }
1159 EXPORT_SYMBOL_GPL(__pm_runtime_disable);
1160
1161 /**
1162  * pm_runtime_enable - Enable runtime PM of a device.
1163  * @dev: Device to handle.
1164  */
1165 void pm_runtime_enable(struct device *dev)
1166 {
1167         unsigned long flags;
1168
1169         spin_lock_irqsave(&dev->power.lock, flags);
1170
1171         if (dev->power.disable_depth > 0)
1172                 dev->power.disable_depth--;
1173         else
1174                 dev_warn(dev, "Unbalanced %s!\n", __func__);
1175
1176         spin_unlock_irqrestore(&dev->power.lock, flags);
1177 }
1178 EXPORT_SYMBOL_GPL(pm_runtime_enable);
1179
1180 /**
1181  * pm_runtime_forbid - Block runtime PM of a device.
1182  * @dev: Device to handle.
1183  *
1184  * Increase the device's usage count and clear its power.runtime_auto flag,
1185  * so that it cannot be suspended at run time until pm_runtime_allow() is called
1186  * for it.
1187  */
1188 void pm_runtime_forbid(struct device *dev)
1189 {
1190         spin_lock_irq(&dev->power.lock);
1191         if (!dev->power.runtime_auto)
1192                 goto out;
1193
1194         dev->power.runtime_auto = false;
1195         atomic_inc(&dev->power.usage_count);
1196         rpm_resume(dev, 0);
1197
1198  out:
1199         spin_unlock_irq(&dev->power.lock);
1200 }
1201 EXPORT_SYMBOL_GPL(pm_runtime_forbid);
1202
1203 /**
1204  * pm_runtime_allow - Unblock runtime PM of a device.
1205  * @dev: Device to handle.
1206  *
1207  * Decrease the device's usage count and set its power.runtime_auto flag.
1208  */
1209 void pm_runtime_allow(struct device *dev)
1210 {
1211         spin_lock_irq(&dev->power.lock);
1212         if (dev->power.runtime_auto)
1213                 goto out;
1214
1215         dev->power.runtime_auto = true;
1216         if (atomic_dec_and_test(&dev->power.usage_count))
1217                 rpm_idle(dev, RPM_AUTO);
1218
1219  out:
1220         spin_unlock_irq(&dev->power.lock);
1221 }
1222 EXPORT_SYMBOL_GPL(pm_runtime_allow);
1223
1224 /**
1225  * pm_runtime_no_callbacks - Ignore runtime PM callbacks for a device.
1226  * @dev: Device to handle.
1227  *
1228  * Set the power.no_callbacks flag, which tells the PM core that this
1229  * device is power-managed through its parent and has no runtime PM
1230  * callbacks of its own.  The runtime sysfs attributes will be removed.
1231  */
1232 void pm_runtime_no_callbacks(struct device *dev)
1233 {
1234         spin_lock_irq(&dev->power.lock);
1235         dev->power.no_callbacks = 1;
1236         spin_unlock_irq(&dev->power.lock);
1237         if (device_is_registered(dev))
1238                 rpm_sysfs_remove(dev);
1239 }
1240 EXPORT_SYMBOL_GPL(pm_runtime_no_callbacks);
1241
1242 /**
1243  * pm_runtime_irq_safe - Leave interrupts disabled during callbacks.
1244  * @dev: Device to handle
1245  *
1246  * Set the power.irq_safe flag, which tells the PM core that the
1247  * ->runtime_suspend() and ->runtime_resume() callbacks for this device should
1248  * always be invoked with the spinlock held and interrupts disabled.  It also
1249  * causes the parent's usage counter to be permanently incremented, preventing
1250  * the parent from runtime suspending -- otherwise an irq-safe child might have
1251  * to wait for a non-irq-safe parent.
1252  */
1253 void pm_runtime_irq_safe(struct device *dev)
1254 {
1255         if (dev->parent)
1256                 pm_runtime_get_sync(dev->parent);
1257         spin_lock_irq(&dev->power.lock);
1258         dev->power.irq_safe = 1;
1259         spin_unlock_irq(&dev->power.lock);
1260 }
1261 EXPORT_SYMBOL_GPL(pm_runtime_irq_safe);
1262
1263 /**
1264  * update_autosuspend - Handle a change to a device's autosuspend settings.
1265  * @dev: Device to handle.
1266  * @old_delay: The former autosuspend_delay value.
1267  * @old_use: The former use_autosuspend value.
1268  *
1269  * Prevent runtime suspend if the new delay is negative and use_autosuspend is
1270  * set; otherwise allow it.  Send an idle notification if suspends are allowed.
1271  *
1272  * This function must be called under dev->power.lock with interrupts disabled.
1273  */
1274 static void update_autosuspend(struct device *dev, int old_delay, int old_use)
1275 {
1276         int delay = dev->power.autosuspend_delay;
1277
1278         /* Should runtime suspend be prevented now? */
1279         if (dev->power.use_autosuspend && delay < 0) {
1280
1281                 /* If it used to be allowed then prevent it. */
1282                 if (!old_use || old_delay >= 0) {
1283                         atomic_inc(&dev->power.usage_count);
1284                         rpm_resume(dev, 0);
1285                 }
1286         }
1287
1288         /* Runtime suspend should be allowed now. */
1289         else {
1290
1291                 /* If it used to be prevented then allow it. */
1292                 if (old_use && old_delay < 0)
1293                         atomic_dec(&dev->power.usage_count);
1294
1295                 /* Maybe we can autosuspend now. */
1296                 rpm_idle(dev, RPM_AUTO);
1297         }
1298 }
1299
1300 /**
1301  * pm_runtime_set_autosuspend_delay - Set a device's autosuspend_delay value.
1302  * @dev: Device to handle.
1303  * @delay: Value of the new delay in milliseconds.
1304  *
1305  * Set the device's power.autosuspend_delay value.  If it changes to negative
1306  * and the power.use_autosuspend flag is set, prevent runtime suspends.  If it
1307  * changes the other way, allow runtime suspends.
1308  */
1309 void pm_runtime_set_autosuspend_delay(struct device *dev, int delay)
1310 {
1311         int old_delay, old_use;
1312
1313         spin_lock_irq(&dev->power.lock);
1314         old_delay = dev->power.autosuspend_delay;
1315         old_use = dev->power.use_autosuspend;
1316         dev->power.autosuspend_delay = delay;
1317         update_autosuspend(dev, old_delay, old_use);
1318         spin_unlock_irq(&dev->power.lock);
1319 }
1320 EXPORT_SYMBOL_GPL(pm_runtime_set_autosuspend_delay);
1321
1322 /**
1323  * __pm_runtime_use_autosuspend - Set a device's use_autosuspend flag.
1324  * @dev: Device to handle.
1325  * @use: New value for use_autosuspend.
1326  *
1327  * Set the device's power.use_autosuspend flag, and allow or prevent runtime
1328  * suspends as needed.
1329  */
1330 void __pm_runtime_use_autosuspend(struct device *dev, bool use)
1331 {
1332         int old_delay, old_use;
1333
1334         spin_lock_irq(&dev->power.lock);
1335         old_delay = dev->power.autosuspend_delay;
1336         old_use = dev->power.use_autosuspend;
1337         dev->power.use_autosuspend = use;
1338         update_autosuspend(dev, old_delay, old_use);
1339         spin_unlock_irq(&dev->power.lock);
1340 }
1341 EXPORT_SYMBOL_GPL(__pm_runtime_use_autosuspend);
1342
1343 /**
1344  * pm_runtime_init - Initialize runtime PM fields in given device object.
1345  * @dev: Device object to initialize.
1346  */
1347 void pm_runtime_init(struct device *dev)
1348 {
1349         dev->power.runtime_status = RPM_SUSPENDED;
1350         dev->power.idle_notification = false;
1351
1352         dev->power.disable_depth = 1;
1353         atomic_set(&dev->power.usage_count, 0);
1354
1355         dev->power.runtime_error = 0;
1356
1357         atomic_set(&dev->power.child_count, 0);
1358         pm_suspend_ignore_children(dev, false);
1359         dev->power.runtime_auto = true;
1360
1361         dev->power.request_pending = false;
1362         dev->power.request = RPM_REQ_NONE;
1363         dev->power.deferred_resume = false;
1364         dev->power.accounting_timestamp = jiffies;
1365         INIT_WORK(&dev->power.work, pm_runtime_work);
1366
1367         dev->power.timer_expires = 0;
1368         setup_timer(&dev->power.suspend_timer, pm_suspend_timer_fn,
1369                         (unsigned long)dev);
1370
1371         dev->power.suspend_time = ktime_set(0, 0);
1372         dev->power.max_time_suspended_ns = -1;
1373
1374         init_waitqueue_head(&dev->power.wait_queue);
1375 }
1376
1377 /**
1378  * pm_runtime_remove - Prepare for removing a device from device hierarchy.
1379  * @dev: Device object being removed from device hierarchy.
1380  */
1381 void pm_runtime_remove(struct device *dev)
1382 {
1383         __pm_runtime_disable(dev, false);
1384
1385         /* Change the status back to 'suspended' to match the initial status. */
1386         if (dev->power.runtime_status == RPM_ACTIVE)
1387                 pm_runtime_set_suspended(dev);
1388         if (dev->power.irq_safe && dev->parent)
1389                 pm_runtime_put_sync(dev->parent);
1390 }
1391
1392 /**
1393  * pm_runtime_update_max_time_suspended - Update device's suspend time data.
1394  * @dev: Device to handle.
1395  * @delta_ns: Value to subtract from the device's max_time_suspended_ns field.
1396  *
1397  * Update the device's power.max_time_suspended_ns field by subtracting
1398  * @delta_ns from it.  The resulting value of power.max_time_suspended_ns is
1399  * never negative.
1400  */
1401 void pm_runtime_update_max_time_suspended(struct device *dev, s64 delta_ns)
1402 {
1403         unsigned long flags;
1404
1405         spin_lock_irqsave(&dev->power.lock, flags);
1406
1407         if (delta_ns > 0 && dev->power.max_time_suspended_ns > 0) {
1408                 if (dev->power.max_time_suspended_ns > delta_ns)
1409                         dev->power.max_time_suspended_ns -= delta_ns;
1410                 else
1411                         dev->power.max_time_suspended_ns = 0;
1412         }
1413
1414         spin_unlock_irqrestore(&dev->power.lock, flags);
1415 }