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