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