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