1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * drivers/base/power/runtime.c - Helper functions for device runtime PM
   4 *
   5 * Copyright (c) 2009 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc.
   6 * Copyright (C) 2010 Alan Stern <stern@rowland.harvard.edu>
   7 */
   8#include <linux/sched/mm.h>
   9#include <linux/ktime.h>
  10#include <linux/hrtimer.h>
  11#include <linux/export.h>
  12#include <linux/pm_runtime.h>
  13#include <linux/pm_wakeirq.h>
  14#include <trace/events/rpm.h>
  15
  16#include "../base.h"
  17#include "power.h"
  18
  19typedef int (*pm_callback_t)(struct device *);
  20
  21static pm_callback_t __rpm_get_callback(struct device *dev, size_t cb_offset)
  22{
  23	pm_callback_t cb;
  24	const struct dev_pm_ops *ops;
  25
  26	if (dev->pm_domain)
  27		ops = &dev->pm_domain->ops;
  28	else if (dev->type && dev->type->pm)
  29		ops = dev->type->pm;
  30	else if (dev->class && dev->class->pm)
  31		ops = dev->class->pm;
  32	else if (dev->bus && dev->bus->pm)
  33		ops = dev->bus->pm;
  34	else
  35		ops = NULL;
  36
  37	if (ops)
  38		cb = *(pm_callback_t *)((void *)ops + cb_offset);
  39	else
  40		cb = NULL;
  41
  42	if (!cb && dev->driver && dev->driver->pm)
  43		cb = *(pm_callback_t *)((void *)dev->driver->pm + cb_offset);
  44
  45	return cb;
  46}
  47
  48#define RPM_GET_CALLBACK(dev, callback) \
  49		__rpm_get_callback(dev, offsetof(struct dev_pm_ops, callback))
  50
  51static int rpm_resume(struct device *dev, int rpmflags);
  52static int rpm_suspend(struct device *dev, int rpmflags);
  53
  54/**
  55 * update_pm_runtime_accounting - Update the time accounting of power states
  56 * @dev: Device to update the accounting for
  57 *
  58 * In order to be able to have time accounting of the various power states
  59 * (as used by programs such as PowerTOP to show the effectiveness of runtime
  60 * PM), we need to track the time spent in each state.
  61 * update_pm_runtime_accounting must be called each time before the
  62 * runtime_status field is updated, to account the time in the old state
  63 * correctly.
  64 */
  65static void update_pm_runtime_accounting(struct device *dev)
  66{
  67	u64 now, last, delta;
  68
  69	if (dev->power.disable_depth > 0)
  70		return;
  71
  72	last = dev->power.accounting_timestamp;
  73
  74	now = ktime_get_mono_fast_ns();
  75	dev->power.accounting_timestamp = now;
  76
  77	/*
  78	 * Because ktime_get_mono_fast_ns() is not monotonic during
  79	 * timekeeping updates, ensure that 'now' is after the last saved
  80	 * timesptamp.
  81	 */
  82	if (now < last)
  83		return;
  84
  85	delta = now - last;
  86
  87	if (dev->power.runtime_status == RPM_SUSPENDED)
  88		dev->power.suspended_time += delta;
  89	else
  90		dev->power.active_time += delta;
  91}
  92
  93static void __update_runtime_status(struct device *dev, enum rpm_status status)
  94{
  95	update_pm_runtime_accounting(dev);
  96	dev->power.runtime_status = status;
  97}
  98
  99static u64 rpm_get_accounted_time(struct device *dev, bool suspended)
 100{
 101	u64 time;
 102	unsigned long flags;
 103
 104	spin_lock_irqsave(&dev->power.lock, flags);
 105
 106	update_pm_runtime_accounting(dev);
 107	time = suspended ? dev->power.suspended_time : dev->power.active_time;
 108
 109	spin_unlock_irqrestore(&dev->power.lock, flags);
 110
 111	return time;
 112}
 113
 114u64 pm_runtime_active_time(struct device *dev)
 115{
 116	return rpm_get_accounted_time(dev, false);
 117}
 118
 119u64 pm_runtime_suspended_time(struct device *dev)
 120{
 121	return rpm_get_accounted_time(dev, true);
 122}
 123EXPORT_SYMBOL_GPL(pm_runtime_suspended_time);
 124
 125/**
 126 * pm_runtime_deactivate_timer - Deactivate given device's suspend timer.
 127 * @dev: Device to handle.
 128 */
 129static void pm_runtime_deactivate_timer(struct device *dev)
 130{
 131	if (dev->power.timer_expires > 0) {
 132		hrtimer_try_to_cancel(&dev->power.suspend_timer);
 133		dev->power.timer_expires = 0;
 134	}
 135}
 136
 137/**
 138 * pm_runtime_cancel_pending - Deactivate suspend timer and cancel requests.
 139 * @dev: Device to handle.
 140 */
 141static void pm_runtime_cancel_pending(struct device *dev)
 142{
 143	pm_runtime_deactivate_timer(dev);
 144	/*
 145	 * In case there's a request pending, make sure its work function will
 146	 * return without doing anything.
 147	 */
 148	dev->power.request = RPM_REQ_NONE;
 149}
 150
 151/*
 152 * pm_runtime_autosuspend_expiration - Get a device's autosuspend-delay expiration time.
 153 * @dev: Device to handle.
 154 *
 155 * Compute the autosuspend-delay expiration time based on the device's
 156 * power.last_busy time.  If the delay has already expired or is disabled
 157 * (negative) or the power.use_autosuspend flag isn't set, return 0.
 158 * Otherwise return the expiration time in nanoseconds (adjusted to be nonzero).
 159 *
 160 * This function may be called either with or without dev->power.lock held.
 161 * Either way it can be racy, since power.last_busy may be updated at any time.
 162 */
 163u64 pm_runtime_autosuspend_expiration(struct device *dev)
 164{
 165	int autosuspend_delay;
 166	u64 expires;
 167
 168	if (!dev->power.use_autosuspend)
 169		return 0;
 170
 171	autosuspend_delay = READ_ONCE(dev->power.autosuspend_delay);
 172	if (autosuspend_delay < 0)
 173		return 0;
 174
 175	expires  = READ_ONCE(dev->power.last_busy);
 176	expires += (u64)autosuspend_delay * NSEC_PER_MSEC;
 177	if (expires > ktime_get_mono_fast_ns())
 178		return expires;	/* Expires in the future */
 179
 180	return 0;
 181}
 182EXPORT_SYMBOL_GPL(pm_runtime_autosuspend_expiration);
 183
 184static int dev_memalloc_noio(struct device *dev, void *data)
 185{
 186	return dev->power.memalloc_noio;
 187}
 188
 189/*
 190 * pm_runtime_set_memalloc_noio - Set a device's memalloc_noio flag.
 191 * @dev: Device to handle.
 192 * @enable: True for setting the flag and False for clearing the flag.
 193 *
 194 * Set the flag for all devices in the path from the device to the
 195 * root device in the device tree if @enable is true, otherwise clear
 196 * the flag for devices in the path whose siblings don't set the flag.
 197 *
 198 * The function should only be called by block device, or network
 199 * device driver for solving the deadlock problem during runtime
 200 * resume/suspend:
 201 *
 202 *     If memory allocation with GFP_KERNEL is called inside runtime
 203 *     resume/suspend callback of any one of its ancestors(or the
 204 *     block device itself), the deadlock may be triggered inside the
 205 *     memory allocation since it might not complete until the block
 206 *     device becomes active and the involed page I/O finishes. The
 207 *     situation is pointed out first by Alan Stern. Network device
 208 *     are involved in iSCSI kind of situation.
 209 *
 210 * The lock of dev_hotplug_mutex is held in the function for handling
 211 * hotplug race because pm_runtime_set_memalloc_noio() may be called
 212 * in async probe().
 213 *
 214 * The function should be called between device_add() and device_del()
 215 * on the affected device(block/network device).
 216 */
 217void pm_runtime_set_memalloc_noio(struct device *dev, bool enable)
 218{
 219	static DEFINE_MUTEX(dev_hotplug_mutex);
 220
 221	mutex_lock(&dev_hotplug_mutex);
 222	for (;;) {
 223		bool enabled;
 224
 225		/* hold power lock since bitfield is not SMP-safe. */
 226		spin_lock_irq(&dev->power.lock);
 227		enabled = dev->power.memalloc_noio;
 228		dev->power.memalloc_noio = enable;
 229		spin_unlock_irq(&dev->power.lock);
 230
 231		/*
 232		 * not need to enable ancestors any more if the device
 233		 * has been enabled.
 234		 */
 235		if (enabled && enable)
 236			break;
 237
 238		dev = dev->parent;
 239
 240		/*
 241		 * clear flag of the parent device only if all the
 242		 * children don't set the flag because ancestor's
 243		 * flag was set by any one of the descendants.
 244		 */
 245		if (!dev || (!enable &&
 246		    device_for_each_child(dev, NULL, dev_memalloc_noio)))
 
 247			break;
 248	}
 249	mutex_unlock(&dev_hotplug_mutex);
 250}
 251EXPORT_SYMBOL_GPL(pm_runtime_set_memalloc_noio);
 252
 253/**
 254 * rpm_check_suspend_allowed - Test whether a device may be suspended.
 255 * @dev: Device to test.
 256 */
 257static int rpm_check_suspend_allowed(struct device *dev)
 258{
 259	int retval = 0;
 260
 261	if (dev->power.runtime_error)
 262		retval = -EINVAL;
 263	else if (dev->power.disable_depth > 0)
 264		retval = -EACCES;
 265	else if (atomic_read(&dev->power.usage_count))
 266		retval = -EAGAIN;
 267	else if (!dev->power.ignore_children && atomic_read(&dev->power.child_count))
 
 268		retval = -EBUSY;
 269
 270	/* Pending resume requests take precedence over suspends. */
 271	else if ((dev->power.deferred_resume &&
 272	    dev->power.runtime_status == RPM_SUSPENDING) ||
 273	    (dev->power.request_pending && dev->power.request == RPM_REQ_RESUME))
 
 274		retval = -EAGAIN;
 275	else if (__dev_pm_qos_resume_latency(dev) == 0)
 276		retval = -EPERM;
 277	else if (dev->power.runtime_status == RPM_SUSPENDED)
 278		retval = 1;
 279
 280	return retval;
 281}
 282
 283static int rpm_get_suppliers(struct device *dev)
 284{
 285	struct device_link *link;
 286
 287	list_for_each_entry_rcu(link, &dev->links.suppliers, c_node,
 288				device_links_read_lock_held()) {
 289		int retval;
 290
 291		if (!(link->flags & DL_FLAG_PM_RUNTIME))
 292			continue;
 293
 294		retval = pm_runtime_get_sync(link->supplier);
 295		/* Ignore suppliers with disabled runtime PM. */
 296		if (retval < 0 && retval != -EACCES) {
 297			pm_runtime_put_noidle(link->supplier);
 298			return retval;
 299		}
 300		refcount_inc(&link->rpm_active);
 301	}
 302	return 0;
 303}
 304
 305/**
 306 * pm_runtime_release_supplier - Drop references to device link's supplier.
 307 * @link: Target device link.
 308 *
 309 * Drop all runtime PM references associated with @link to its supplier device.
 310 */
 311void pm_runtime_release_supplier(struct device_link *link)
 312{
 313	struct device *supplier = link->supplier;
 314
 315	/*
 316	 * The additional power.usage_count check is a safety net in case
 317	 * the rpm_active refcount becomes saturated, in which case
 318	 * refcount_dec_not_one() would return true forever, but it is not
 319	 * strictly necessary.
 320	 */
 321	while (refcount_dec_not_one(&link->rpm_active) &&
 322	       atomic_read(&supplier->power.usage_count) > 0)
 323		pm_runtime_put_noidle(supplier);
 324}
 325
 326static void __rpm_put_suppliers(struct device *dev, bool try_to_suspend)
 327{
 328	struct device_link *link;
 329
 330	list_for_each_entry_rcu(link, &dev->links.suppliers, c_node,
 331				device_links_read_lock_held()) {
 332		pm_runtime_release_supplier(link);
 
 
 
 333		if (try_to_suspend)
 334			pm_request_idle(link->supplier);
 335	}
 336}
 337
 338static void rpm_put_suppliers(struct device *dev)
 339{
 340	__rpm_put_suppliers(dev, true);
 341}
 342
 343static void rpm_suspend_suppliers(struct device *dev)
 344{
 345	struct device_link *link;
 346	int idx = device_links_read_lock();
 347
 348	list_for_each_entry_rcu(link, &dev->links.suppliers, c_node,
 349				device_links_read_lock_held())
 350		pm_request_idle(link->supplier);
 351
 352	device_links_read_unlock(idx);
 353}
 354
 355/**
 356 * __rpm_callback - Run a given runtime PM callback for a given device.
 357 * @cb: Runtime PM callback to run.
 358 * @dev: Device to run the callback for.
 359 */
 360static int __rpm_callback(int (*cb)(struct device *), struct device *dev)
 361	__releases(&dev->power.lock) __acquires(&dev->power.lock)
 362{
 363	int retval = 0, idx;
 364	bool use_links = dev->power.links_count > 0;
 365
 366	if (dev->power.irq_safe) {
 367		spin_unlock(&dev->power.lock);
 368	} else {
 369		spin_unlock_irq(&dev->power.lock);
 370
 371		/*
 372		 * Resume suppliers if necessary.
 373		 *
 374		 * The device's runtime PM status cannot change until this
 375		 * routine returns, so it is safe to read the status outside of
 376		 * the lock.
 377		 */
 378		if (use_links && dev->power.runtime_status == RPM_RESUMING) {
 379			idx = device_links_read_lock();
 380
 381			retval = rpm_get_suppliers(dev);
 382			if (retval) {
 383				rpm_put_suppliers(dev);
 384				goto fail;
 385			}
 386
 387			device_links_read_unlock(idx);
 388		}
 389	}
 390
 391	if (cb)
 392		retval = cb(dev);
 393
 394	if (dev->power.irq_safe) {
 395		spin_lock(&dev->power.lock);
 396	} else {
 397		/*
 398		 * If the device is suspending and the callback has returned
 399		 * success, drop the usage counters of the suppliers that have
 400		 * been reference counted on its resume.
 401		 *
 402		 * Do that if resume fails too.
 403		 */
 404		if (use_links &&
 405		    ((dev->power.runtime_status == RPM_SUSPENDING && !retval) ||
 406		    (dev->power.runtime_status == RPM_RESUMING && retval))) {
 407			idx = device_links_read_lock();
 408
 409			__rpm_put_suppliers(dev, false);
 410
 411fail:
 412			device_links_read_unlock(idx);
 413		}
 414
 415		spin_lock_irq(&dev->power.lock);
 416	}
 417
 418	return retval;
 419}
 420
 421/**
 422 * rpm_callback - Run a given runtime PM callback for a given device.
 423 * @cb: Runtime PM callback to run.
 424 * @dev: Device to run the callback for.
 425 */
 426static int rpm_callback(int (*cb)(struct device *), struct device *dev)
 427{
 428	int retval;
 429
 430	if (dev->power.memalloc_noio) {
 431		unsigned int noio_flag;
 432
 433		/*
 434		 * Deadlock might be caused if memory allocation with
 435		 * GFP_KERNEL happens inside runtime_suspend and
 436		 * runtime_resume callbacks of one block device's
 437		 * ancestor or the block device itself. Network
 438		 * device might be thought as part of iSCSI block
 439		 * device, so network device and its ancestor should
 440		 * be marked as memalloc_noio too.
 441		 */
 442		noio_flag = memalloc_noio_save();
 443		retval = __rpm_callback(cb, dev);
 444		memalloc_noio_restore(noio_flag);
 445	} else {
 446		retval = __rpm_callback(cb, dev);
 447	}
 448
 449	dev->power.runtime_error = retval;
 450	return retval != -EACCES ? retval : -EIO;
 451}
 452
 453/**
 454 * rpm_idle - Notify device bus type if the device can be suspended.
 455 * @dev: Device to notify the bus type about.
 456 * @rpmflags: Flag bits.
 457 *
 458 * Check if the device's runtime PM status allows it to be suspended.  If
 459 * another idle notification has been started earlier, return immediately.  If
 460 * the RPM_ASYNC flag is set then queue an idle-notification request; otherwise
 461 * run the ->runtime_idle() callback directly. If the ->runtime_idle callback
 462 * doesn't exist or if it returns 0, call rpm_suspend with the RPM_AUTO flag.
 463 *
 464 * This function must be called under dev->power.lock with interrupts disabled.
 465 */
 466static int rpm_idle(struct device *dev, int rpmflags)
 467{
 468	int (*callback)(struct device *);
 469	int retval;
 470
 471	trace_rpm_idle_rcuidle(dev, rpmflags);
 472	retval = rpm_check_suspend_allowed(dev);
 473	if (retval < 0)
 474		;	/* Conditions are wrong. */
 475
 476	/* Idle notifications are allowed only in the RPM_ACTIVE state. */
 477	else if (dev->power.runtime_status != RPM_ACTIVE)
 478		retval = -EAGAIN;
 479
 480	/*
 481	 * Any pending request other than an idle notification takes
 482	 * precedence over us, except that the timer may be running.
 483	 */
 484	else if (dev->power.request_pending &&
 485	    dev->power.request > RPM_REQ_IDLE)
 486		retval = -EAGAIN;
 487
 488	/* Act as though RPM_NOWAIT is always set. */
 489	else if (dev->power.idle_notification)
 490		retval = -EINPROGRESS;
 491
 492	if (retval)
 493		goto out;
 494
 495	/* Pending requests need to be canceled. */
 496	dev->power.request = RPM_REQ_NONE;
 497
 498	callback = RPM_GET_CALLBACK(dev, runtime_idle);
 499
 500	/* If no callback assume success. */
 501	if (!callback || dev->power.no_callbacks)
 502		goto out;
 503
 504	/* Carry out an asynchronous or a synchronous idle notification. */
 505	if (rpmflags & RPM_ASYNC) {
 506		dev->power.request = RPM_REQ_IDLE;
 507		if (!dev->power.request_pending) {
 508			dev->power.request_pending = true;
 509			queue_work(pm_wq, &dev->power.work);
 510		}
 511		trace_rpm_return_int_rcuidle(dev, _THIS_IP_, 0);
 512		return 0;
 513	}
 514
 515	dev->power.idle_notification = true;
 516
 517	if (dev->power.irq_safe)
 518		spin_unlock(&dev->power.lock);
 519	else
 520		spin_unlock_irq(&dev->power.lock);
 521
 522	retval = callback(dev);
 523
 524	if (dev->power.irq_safe)
 525		spin_lock(&dev->power.lock);
 526	else
 527		spin_lock_irq(&dev->power.lock);
 528
 529	dev->power.idle_notification = false;
 530	wake_up_all(&dev->power.wait_queue);
 531
 532 out:
 533	trace_rpm_return_int_rcuidle(dev, _THIS_IP_, retval);
 534	return retval ? retval : rpm_suspend(dev, rpmflags | RPM_AUTO);
 535}
 536
 537/**
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 538 * rpm_suspend - Carry out runtime suspend of given device.
 539 * @dev: Device to suspend.
 540 * @rpmflags: Flag bits.
 541 *
 542 * Check if the device's runtime PM status allows it to be suspended.
 543 * Cancel a pending idle notification, autosuspend or suspend. If
 544 * another suspend has been started earlier, either return immediately
 545 * or wait for it to finish, depending on the RPM_NOWAIT and RPM_ASYNC
 546 * flags. If the RPM_ASYNC flag is set then queue a suspend request;
 547 * otherwise run the ->runtime_suspend() callback directly. When
 548 * ->runtime_suspend succeeded, if a deferred resume was requested while
 549 * the callback was running then carry it out, otherwise send an idle
 550 * notification for its parent (if the suspend succeeded and both
 551 * ignore_children of parent->power and irq_safe of dev->power are not set).
 552 * If ->runtime_suspend failed with -EAGAIN or -EBUSY, and if the RPM_AUTO
 553 * flag is set and the next autosuspend-delay expiration time is in the
 554 * future, schedule another autosuspend attempt.
 555 *
 556 * This function must be called under dev->power.lock with interrupts disabled.
 557 */
 558static int rpm_suspend(struct device *dev, int rpmflags)
 559	__releases(&dev->power.lock) __acquires(&dev->power.lock)
 560{
 561	int (*callback)(struct device *);
 562	struct device *parent = NULL;
 563	int retval;
 564
 565	trace_rpm_suspend_rcuidle(dev, rpmflags);
 566
 567 repeat:
 568	retval = rpm_check_suspend_allowed(dev);
 569	if (retval < 0)
 570		goto out;	/* Conditions are wrong. */
 571
 572	/* Synchronous suspends are not allowed in the RPM_RESUMING state. */
 573	if (dev->power.runtime_status == RPM_RESUMING && !(rpmflags & RPM_ASYNC))
 574		retval = -EAGAIN;
 575
 576	if (retval)
 577		goto out;
 578
 579	/* If the autosuspend_delay time hasn't expired yet, reschedule. */
 580	if ((rpmflags & RPM_AUTO) && dev->power.runtime_status != RPM_SUSPENDING) {
 
 581		u64 expires = pm_runtime_autosuspend_expiration(dev);
 582
 583		if (expires != 0) {
 584			/* Pending requests need to be canceled. */
 585			dev->power.request = RPM_REQ_NONE;
 586
 587			/*
 588			 * Optimization: If the timer is already running and is
 589			 * set to expire at or before the autosuspend delay,
 590			 * avoid the overhead of resetting it.  Just let it
 591			 * expire; pm_suspend_timer_fn() will take care of the
 592			 * rest.
 593			 */
 594			if (!(dev->power.timer_expires &&
 595			    dev->power.timer_expires <= expires)) {
 596				/*
 597				 * We add a slack of 25% to gather wakeups
 598				 * without sacrificing the granularity.
 599				 */
 600				u64 slack = (u64)READ_ONCE(dev->power.autosuspend_delay) *
 601						    (NSEC_PER_MSEC >> 2);
 602
 603				dev->power.timer_expires = expires;
 604				hrtimer_start_range_ns(&dev->power.suspend_timer,
 605						       ns_to_ktime(expires),
 606						       slack,
 607						       HRTIMER_MODE_ABS);
 608			}
 609			dev->power.timer_autosuspends = 1;
 610			goto out;
 611		}
 612	}
 613
 614	/* Other scheduled or pending requests need to be canceled. */
 615	pm_runtime_cancel_pending(dev);
 616
 617	if (dev->power.runtime_status == RPM_SUSPENDING) {
 618		DEFINE_WAIT(wait);
 619
 620		if (rpmflags & (RPM_ASYNC | RPM_NOWAIT)) {
 621			retval = -EINPROGRESS;
 622			goto out;
 623		}
 624
 625		if (dev->power.irq_safe) {
 626			spin_unlock(&dev->power.lock);
 627
 628			cpu_relax();
 629
 630			spin_lock(&dev->power.lock);
 631			goto repeat;
 632		}
 633
 634		/* Wait for the other suspend running in parallel with us. */
 635		for (;;) {
 636			prepare_to_wait(&dev->power.wait_queue, &wait,
 637					TASK_UNINTERRUPTIBLE);
 638			if (dev->power.runtime_status != RPM_SUSPENDING)
 639				break;
 640
 641			spin_unlock_irq(&dev->power.lock);
 642
 643			schedule();
 644
 645			spin_lock_irq(&dev->power.lock);
 646		}
 647		finish_wait(&dev->power.wait_queue, &wait);
 648		goto repeat;
 649	}
 650
 651	if (dev->power.no_callbacks)
 652		goto no_callback;	/* Assume success. */
 653
 654	/* Carry out an asynchronous or a synchronous suspend. */
 655	if (rpmflags & RPM_ASYNC) {
 656		dev->power.request = (rpmflags & RPM_AUTO) ?
 657		    RPM_REQ_AUTOSUSPEND : RPM_REQ_SUSPEND;
 658		if (!dev->power.request_pending) {
 659			dev->power.request_pending = true;
 660			queue_work(pm_wq, &dev->power.work);
 661		}
 662		goto out;
 663	}
 664
 665	__update_runtime_status(dev, RPM_SUSPENDING);
 666
 667	callback = RPM_GET_CALLBACK(dev, runtime_suspend);
 668
 669	dev_pm_enable_wake_irq_check(dev, true);
 670	retval = rpm_callback(callback, dev);
 671	if (retval)
 672		goto fail;
 673
 674	dev_pm_enable_wake_irq_complete(dev);
 675
 676 no_callback:
 677	__update_runtime_status(dev, RPM_SUSPENDED);
 678	pm_runtime_deactivate_timer(dev);
 679
 680	if (dev->parent) {
 681		parent = dev->parent;
 682		atomic_add_unless(&parent->power.child_count, -1, 0);
 683	}
 684	wake_up_all(&dev->power.wait_queue);
 685
 686	if (dev->power.deferred_resume) {
 687		dev->power.deferred_resume = false;
 688		rpm_resume(dev, 0);
 689		retval = -EAGAIN;
 690		goto out;
 691	}
 692
 693	if (dev->power.irq_safe)
 694		goto out;
 695
 696	/* Maybe the parent is now able to suspend. */
 697	if (parent && !parent->power.ignore_children) {
 698		spin_unlock(&dev->power.lock);
 699
 700		spin_lock(&parent->power.lock);
 701		rpm_idle(parent, RPM_ASYNC);
 702		spin_unlock(&parent->power.lock);
 703
 704		spin_lock(&dev->power.lock);
 705	}
 706	/* Maybe the suppliers are now able to suspend. */
 707	if (dev->power.links_count > 0) {
 708		spin_unlock_irq(&dev->power.lock);
 709
 710		rpm_suspend_suppliers(dev);
 711
 712		spin_lock_irq(&dev->power.lock);
 713	}
 714
 715 out:
 716	trace_rpm_return_int_rcuidle(dev, _THIS_IP_, retval);
 717
 718	return retval;
 719
 720 fail:
 721	dev_pm_disable_wake_irq_check(dev, true);
 722	__update_runtime_status(dev, RPM_ACTIVE);
 723	dev->power.deferred_resume = false;
 724	wake_up_all(&dev->power.wait_queue);
 725
 726	if (retval == -EAGAIN || retval == -EBUSY) {
 727		dev->power.runtime_error = 0;
 728
 729		/*
 730		 * If the callback routine failed an autosuspend, and
 731		 * if the last_busy time has been updated so that there
 732		 * is a new autosuspend expiration time, automatically
 733		 * reschedule another autosuspend.
 734		 */
 735		if ((rpmflags & RPM_AUTO) &&
 736		    pm_runtime_autosuspend_expiration(dev) != 0)
 737			goto repeat;
 738	} else {
 739		pm_runtime_cancel_pending(dev);
 740	}
 741	goto out;
 742}
 743
 744/**
 745 * rpm_resume - Carry out runtime resume of given device.
 746 * @dev: Device to resume.
 747 * @rpmflags: Flag bits.
 748 *
 749 * Check if the device's runtime PM status allows it to be resumed.  Cancel
 750 * any scheduled or pending requests.  If another resume has been started
 751 * earlier, either return immediately or wait for it to finish, depending on the
 752 * RPM_NOWAIT and RPM_ASYNC flags.  Similarly, if there's a suspend running in
 753 * parallel with this function, either tell the other process to resume after
 754 * suspending (deferred_resume) or wait for it to finish.  If the RPM_ASYNC
 755 * flag is set then queue a resume request; otherwise run the
 756 * ->runtime_resume() callback directly.  Queue an idle notification for the
 757 * device if the resume succeeded.
 758 *
 759 * This function must be called under dev->power.lock with interrupts disabled.
 760 */
 761static int rpm_resume(struct device *dev, int rpmflags)
 762	__releases(&dev->power.lock) __acquires(&dev->power.lock)
 763{
 764	int (*callback)(struct device *);
 765	struct device *parent = NULL;
 766	int retval = 0;
 767
 768	trace_rpm_resume_rcuidle(dev, rpmflags);
 769
 770 repeat:
 771	if (dev->power.runtime_error) {
 772		retval = -EINVAL;
 773	} else if (dev->power.disable_depth > 0) {
 774		if (dev->power.runtime_status == RPM_ACTIVE &&
 775		    dev->power.last_status == RPM_ACTIVE)
 776			retval = 1;
 777		else
 778			retval = -EACCES;
 779	}
 780	if (retval)
 781		goto out;
 782
 783	/*
 784	 * Other scheduled or pending requests need to be canceled.  Small
 785	 * optimization: If an autosuspend timer is running, leave it running
 786	 * rather than cancelling it now only to restart it again in the near
 787	 * future.
 788	 */
 789	dev->power.request = RPM_REQ_NONE;
 790	if (!dev->power.timer_autosuspends)
 791		pm_runtime_deactivate_timer(dev);
 792
 793	if (dev->power.runtime_status == RPM_ACTIVE) {
 794		retval = 1;
 795		goto out;
 796	}
 797
 798	if (dev->power.runtime_status == RPM_RESUMING ||
 799	    dev->power.runtime_status == RPM_SUSPENDING) {
 800		DEFINE_WAIT(wait);
 801
 802		if (rpmflags & (RPM_ASYNC | RPM_NOWAIT)) {
 803			if (dev->power.runtime_status == RPM_SUSPENDING) {
 804				dev->power.deferred_resume = true;
 805				if (rpmflags & RPM_NOWAIT)
 806					retval = -EINPROGRESS;
 807			} else {
 808				retval = -EINPROGRESS;
 809			}
 810			goto out;
 811		}
 812
 813		if (dev->power.irq_safe) {
 814			spin_unlock(&dev->power.lock);
 815
 816			cpu_relax();
 817
 818			spin_lock(&dev->power.lock);
 819			goto repeat;
 820		}
 821
 822		/* Wait for the operation carried out in parallel with us. */
 823		for (;;) {
 824			prepare_to_wait(&dev->power.wait_queue, &wait,
 825					TASK_UNINTERRUPTIBLE);
 826			if (dev->power.runtime_status != RPM_RESUMING &&
 827			    dev->power.runtime_status != RPM_SUSPENDING)
 828				break;
 829
 830			spin_unlock_irq(&dev->power.lock);
 831
 832			schedule();
 833
 834			spin_lock_irq(&dev->power.lock);
 835		}
 836		finish_wait(&dev->power.wait_queue, &wait);
 837		goto repeat;
 838	}
 839
 840	/*
 841	 * See if we can skip waking up the parent.  This is safe only if
 842	 * power.no_callbacks is set, because otherwise we don't know whether
 843	 * the resume will actually succeed.
 844	 */
 845	if (dev->power.no_callbacks && !parent && dev->parent) {
 846		spin_lock_nested(&dev->parent->power.lock, SINGLE_DEPTH_NESTING);
 847		if (dev->parent->power.disable_depth > 0 ||
 848		    dev->parent->power.ignore_children ||
 849		    dev->parent->power.runtime_status == RPM_ACTIVE) {
 850			atomic_inc(&dev->parent->power.child_count);
 851			spin_unlock(&dev->parent->power.lock);
 852			retval = 1;
 853			goto no_callback;	/* Assume success. */
 854		}
 855		spin_unlock(&dev->parent->power.lock);
 856	}
 857
 858	/* Carry out an asynchronous or a synchronous resume. */
 859	if (rpmflags & RPM_ASYNC) {
 860		dev->power.request = RPM_REQ_RESUME;
 861		if (!dev->power.request_pending) {
 862			dev->power.request_pending = true;
 863			queue_work(pm_wq, &dev->power.work);
 864		}
 865		retval = 0;
 866		goto out;
 867	}
 868
 869	if (!parent && dev->parent) {
 870		/*
 871		 * Increment the parent's usage counter and resume it if
 872		 * necessary.  Not needed if dev is irq-safe; then the
 873		 * parent is permanently resumed.
 874		 */
 875		parent = dev->parent;
 876		if (dev->power.irq_safe)
 877			goto skip_parent;
 878
 879		spin_unlock(&dev->power.lock);
 880
 881		pm_runtime_get_noresume(parent);
 882
 883		spin_lock(&parent->power.lock);
 884		/*
 885		 * Resume the parent if it has runtime PM enabled and not been
 886		 * set to ignore its children.
 887		 */
 888		if (!parent->power.disable_depth &&
 889		    !parent->power.ignore_children) {
 890			rpm_resume(parent, 0);
 891			if (parent->power.runtime_status != RPM_ACTIVE)
 892				retval = -EBUSY;
 893		}
 894		spin_unlock(&parent->power.lock);
 895
 896		spin_lock(&dev->power.lock);
 897		if (retval)
 898			goto out;
 899
 900		goto repeat;
 901	}
 902 skip_parent:
 903
 904	if (dev->power.no_callbacks)
 905		goto no_callback;	/* Assume success. */
 906
 907	__update_runtime_status(dev, RPM_RESUMING);
 908
 909	callback = RPM_GET_CALLBACK(dev, runtime_resume);
 910
 911	dev_pm_disable_wake_irq_check(dev, false);
 912	retval = rpm_callback(callback, dev);
 913	if (retval) {
 914		__update_runtime_status(dev, RPM_SUSPENDED);
 915		pm_runtime_cancel_pending(dev);
 916		dev_pm_enable_wake_irq_check(dev, false);
 917	} else {
 918 no_callback:
 919		__update_runtime_status(dev, RPM_ACTIVE);
 920		pm_runtime_mark_last_busy(dev);
 921		if (parent)
 922			atomic_inc(&parent->power.child_count);
 923	}
 924	wake_up_all(&dev->power.wait_queue);
 925
 926	if (retval >= 0)
 927		rpm_idle(dev, RPM_ASYNC);
 928
 929 out:
 930	if (parent && !dev->power.irq_safe) {
 931		spin_unlock_irq(&dev->power.lock);
 932
 933		pm_runtime_put(parent);
 934
 935		spin_lock_irq(&dev->power.lock);
 936	}
 937
 938	trace_rpm_return_int_rcuidle(dev, _THIS_IP_, retval);
 939
 940	return retval;
 941}
 942
 943/**
 944 * pm_runtime_work - Universal runtime PM work function.
 945 * @work: Work structure used for scheduling the execution of this function.
 946 *
 947 * Use @work to get the device object the work is to be done for, determine what
 948 * is to be done and execute the appropriate runtime PM function.
 949 */
 950static void pm_runtime_work(struct work_struct *work)
 951{
 952	struct device *dev = container_of(work, struct device, power.work);
 953	enum rpm_request req;
 954
 955	spin_lock_irq(&dev->power.lock);
 956
 957	if (!dev->power.request_pending)
 958		goto out;
 959
 960	req = dev->power.request;
 961	dev->power.request = RPM_REQ_NONE;
 962	dev->power.request_pending = false;
 963
 964	switch (req) {
 965	case RPM_REQ_NONE:
 966		break;
 967	case RPM_REQ_IDLE:
 968		rpm_idle(dev, RPM_NOWAIT);
 969		break;
 970	case RPM_REQ_SUSPEND:
 971		rpm_suspend(dev, RPM_NOWAIT);
 972		break;
 973	case RPM_REQ_AUTOSUSPEND:
 974		rpm_suspend(dev, RPM_NOWAIT | RPM_AUTO);
 975		break;
 976	case RPM_REQ_RESUME:
 977		rpm_resume(dev, RPM_NOWAIT);
 978		break;
 979	}
 980
 981 out:
 982	spin_unlock_irq(&dev->power.lock);
 983}
 984
 985/**
 986 * pm_suspend_timer_fn - Timer function for pm_schedule_suspend().
 987 * @timer: hrtimer used by pm_schedule_suspend().
 988 *
 989 * Check if the time is right and queue a suspend request.
 990 */
 991static enum hrtimer_restart  pm_suspend_timer_fn(struct hrtimer *timer)
 992{
 993	struct device *dev = container_of(timer, struct device, power.suspend_timer);
 994	unsigned long flags;
 995	u64 expires;
 996
 997	spin_lock_irqsave(&dev->power.lock, flags);
 998
 999	expires = dev->power.timer_expires;
1000	/*
1001	 * If 'expires' is after the current time, we've been called
1002	 * too early.
1003	 */
1004	if (expires > 0 && expires < ktime_get_mono_fast_ns()) {
1005		dev->power.timer_expires = 0;
1006		rpm_suspend(dev, dev->power.timer_autosuspends ?
1007		    (RPM_ASYNC | RPM_AUTO) : RPM_ASYNC);
1008	}
1009
1010	spin_unlock_irqrestore(&dev->power.lock, flags);
1011
1012	return HRTIMER_NORESTART;
1013}
1014
1015/**
1016 * pm_schedule_suspend - Set up a timer to submit a suspend request in future.
1017 * @dev: Device to suspend.
1018 * @delay: Time to wait before submitting a suspend request, in milliseconds.
1019 */
1020int pm_schedule_suspend(struct device *dev, unsigned int delay)
1021{
1022	unsigned long flags;
1023	u64 expires;
1024	int retval;
1025
1026	spin_lock_irqsave(&dev->power.lock, flags);
1027
1028	if (!delay) {
1029		retval = rpm_suspend(dev, RPM_ASYNC);
1030		goto out;
1031	}
1032
1033	retval = rpm_check_suspend_allowed(dev);
1034	if (retval)
1035		goto out;
1036
1037	/* Other scheduled or pending requests need to be canceled. */
1038	pm_runtime_cancel_pending(dev);
1039
1040	expires = ktime_get_mono_fast_ns() + (u64)delay * NSEC_PER_MSEC;
1041	dev->power.timer_expires = expires;
1042	dev->power.timer_autosuspends = 0;
1043	hrtimer_start(&dev->power.suspend_timer, expires, HRTIMER_MODE_ABS);
1044
1045 out:
1046	spin_unlock_irqrestore(&dev->power.lock, flags);
1047
1048	return retval;
1049}
1050EXPORT_SYMBOL_GPL(pm_schedule_suspend);
1051
1052static int rpm_drop_usage_count(struct device *dev)
1053{
1054	int ret;
1055
1056	ret = atomic_sub_return(1, &dev->power.usage_count);
1057	if (ret >= 0)
1058		return ret;
1059
1060	/*
1061	 * Because rpm_resume() does not check the usage counter, it will resume
1062	 * the device even if the usage counter is 0 or negative, so it is
1063	 * sufficient to increment the usage counter here to reverse the change
1064	 * made above.
1065	 */
1066	atomic_inc(&dev->power.usage_count);
1067	dev_warn(dev, "Runtime PM usage count underflow!\n");
1068	return -EINVAL;
1069}
1070
1071/**
1072 * __pm_runtime_idle - Entry point for runtime idle operations.
1073 * @dev: Device to send idle notification for.
1074 * @rpmflags: Flag bits.
1075 *
1076 * If the RPM_GET_PUT flag is set, decrement the device's usage count and
1077 * return immediately if it is larger than zero (if it becomes negative, log a
1078 * warning, increment it, and return an error).  Then carry out an idle
1079 * notification, either synchronous or asynchronous.
1080 *
1081 * This routine may be called in atomic context if the RPM_ASYNC flag is set,
1082 * or if pm_runtime_irq_safe() has been called.
1083 */
1084int __pm_runtime_idle(struct device *dev, int rpmflags)
1085{
1086	unsigned long flags;
1087	int retval;
1088
1089	if (rpmflags & RPM_GET_PUT) {
1090		retval = rpm_drop_usage_count(dev);
1091		if (retval < 0) {
1092			return retval;
1093		} else if (retval > 0) {
1094			trace_rpm_usage_rcuidle(dev, rpmflags);
1095			return 0;
1096		}
1097	}
1098
1099	might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe);
1100
1101	spin_lock_irqsave(&dev->power.lock, flags);
1102	retval = rpm_idle(dev, rpmflags);
1103	spin_unlock_irqrestore(&dev->power.lock, flags);
1104
1105	return retval;
1106}
1107EXPORT_SYMBOL_GPL(__pm_runtime_idle);
1108
1109/**
1110 * __pm_runtime_suspend - Entry point for runtime put/suspend operations.
1111 * @dev: Device to suspend.
1112 * @rpmflags: Flag bits.
1113 *
1114 * If the RPM_GET_PUT flag is set, decrement the device's usage count and
1115 * return immediately if it is larger than zero (if it becomes negative, log a
1116 * warning, increment it, and return an error).  Then carry out a suspend,
1117 * either synchronous or asynchronous.
1118 *
1119 * This routine may be called in atomic context if the RPM_ASYNC flag is set,
1120 * or if pm_runtime_irq_safe() has been called.
1121 */
1122int __pm_runtime_suspend(struct device *dev, int rpmflags)
1123{
1124	unsigned long flags;
1125	int retval;
1126
1127	if (rpmflags & RPM_GET_PUT) {
1128		retval = rpm_drop_usage_count(dev);
1129		if (retval < 0) {
1130			return retval;
1131		} else if (retval > 0) {
1132			trace_rpm_usage_rcuidle(dev, rpmflags);
1133			return 0;
1134		}
1135	}
1136
1137	might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe);
1138
1139	spin_lock_irqsave(&dev->power.lock, flags);
1140	retval = rpm_suspend(dev, rpmflags);
1141	spin_unlock_irqrestore(&dev->power.lock, flags);
1142
1143	return retval;
1144}
1145EXPORT_SYMBOL_GPL(__pm_runtime_suspend);
1146
1147/**
1148 * __pm_runtime_resume - Entry point for runtime resume operations.
1149 * @dev: Device to resume.
1150 * @rpmflags: Flag bits.
1151 *
1152 * If the RPM_GET_PUT flag is set, increment the device's usage count.  Then
1153 * carry out a resume, either synchronous or asynchronous.
1154 *
1155 * This routine may be called in atomic context if the RPM_ASYNC flag is set,
1156 * or if pm_runtime_irq_safe() has been called.
1157 */
1158int __pm_runtime_resume(struct device *dev, int rpmflags)
1159{
1160	unsigned long flags;
1161	int retval;
1162
1163	might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe &&
1164			dev->power.runtime_status != RPM_ACTIVE);
1165
1166	if (rpmflags & RPM_GET_PUT)
1167		atomic_inc(&dev->power.usage_count);
1168
1169	spin_lock_irqsave(&dev->power.lock, flags);
1170	retval = rpm_resume(dev, rpmflags);
1171	spin_unlock_irqrestore(&dev->power.lock, flags);
1172
1173	return retval;
1174}
1175EXPORT_SYMBOL_GPL(__pm_runtime_resume);
1176
1177/**
1178 * pm_runtime_get_if_active - Conditionally bump up device usage counter.
1179 * @dev: Device to handle.
1180 * @ign_usage_count: Whether or not to look at the current usage counter value.
1181 *
1182 * Return -EINVAL if runtime PM is disabled for @dev.
1183 *
1184 * Otherwise, if the runtime PM status of @dev is %RPM_ACTIVE and either
1185 * @ign_usage_count is %true or the runtime PM usage counter of @dev is not
1186 * zero, increment the usage counter of @dev and return 1. Otherwise, return 0
1187 * without changing the usage counter.
1188 *
1189 * If @ign_usage_count is %true, this function can be used to prevent suspending
1190 * the device when its runtime PM status is %RPM_ACTIVE.
1191 *
1192 * If @ign_usage_count is %false, this function can be used to prevent
1193 * suspending the device when both its runtime PM status is %RPM_ACTIVE and its
1194 * runtime PM usage counter is not zero.
1195 *
1196 * The caller is responsible for decrementing the runtime PM usage counter of
1197 * @dev after this function has returned a positive value for it.
1198 */
1199int pm_runtime_get_if_active(struct device *dev, bool ign_usage_count)
1200{
1201	unsigned long flags;
1202	int retval;
1203
1204	spin_lock_irqsave(&dev->power.lock, flags);
1205	if (dev->power.disable_depth > 0) {
1206		retval = -EINVAL;
1207	} else if (dev->power.runtime_status != RPM_ACTIVE) {
1208		retval = 0;
1209	} else if (ign_usage_count) {
1210		retval = 1;
1211		atomic_inc(&dev->power.usage_count);
1212	} else {
1213		retval = atomic_inc_not_zero(&dev->power.usage_count);
1214	}
1215	trace_rpm_usage_rcuidle(dev, 0);
1216	spin_unlock_irqrestore(&dev->power.lock, flags);
1217
1218	return retval;
1219}
1220EXPORT_SYMBOL_GPL(pm_runtime_get_if_active);
1221
1222/**
1223 * __pm_runtime_set_status - Set runtime PM status of a device.
1224 * @dev: Device to handle.
1225 * @status: New runtime PM status of the device.
1226 *
1227 * If runtime PM of the device is disabled or its power.runtime_error field is
1228 * different from zero, the status may be changed either to RPM_ACTIVE, or to
1229 * RPM_SUSPENDED, as long as that reflects the actual state of the device.
1230 * However, if the device has a parent and the parent is not active, and the
1231 * parent's power.ignore_children flag is unset, the device's status cannot be
1232 * set to RPM_ACTIVE, so -EBUSY is returned in that case.
1233 *
1234 * If successful, __pm_runtime_set_status() clears the power.runtime_error field
1235 * and the device parent's counter of unsuspended children is modified to
1236 * reflect the new status.  If the new status is RPM_SUSPENDED, an idle
1237 * notification request for the parent is submitted.
1238 *
1239 * If @dev has any suppliers (as reflected by device links to them), and @status
1240 * is RPM_ACTIVE, they will be activated upfront and if the activation of one
1241 * of them fails, the status of @dev will be changed to RPM_SUSPENDED (instead
1242 * of the @status value) and the suppliers will be deacticated on exit.  The
1243 * error returned by the failing supplier activation will be returned in that
1244 * case.
1245 */
1246int __pm_runtime_set_status(struct device *dev, unsigned int status)
1247{
1248	struct device *parent = dev->parent;
1249	bool notify_parent = false;
1250	unsigned long flags;
1251	int error = 0;
1252
1253	if (status != RPM_ACTIVE && status != RPM_SUSPENDED)
1254		return -EINVAL;
1255
1256	spin_lock_irqsave(&dev->power.lock, flags);
1257
1258	/*
1259	 * Prevent PM-runtime from being enabled for the device or return an
1260	 * error if it is enabled already and working.
1261	 */
1262	if (dev->power.runtime_error || dev->power.disable_depth)
1263		dev->power.disable_depth++;
1264	else
1265		error = -EAGAIN;
1266
1267	spin_unlock_irqrestore(&dev->power.lock, flags);
1268
1269	if (error)
1270		return error;
1271
1272	/*
1273	 * If the new status is RPM_ACTIVE, the suppliers can be activated
1274	 * upfront regardless of the current status, because next time
1275	 * rpm_put_suppliers() runs, the rpm_active refcounts of the links
1276	 * involved will be dropped down to one anyway.
1277	 */
1278	if (status == RPM_ACTIVE) {
1279		int idx = device_links_read_lock();
1280
1281		error = rpm_get_suppliers(dev);
1282		if (error)
1283			status = RPM_SUSPENDED;
1284
1285		device_links_read_unlock(idx);
1286	}
1287
1288	spin_lock_irqsave(&dev->power.lock, flags);
1289
1290	if (dev->power.runtime_status == status || !parent)
1291		goto out_set;
1292
1293	if (status == RPM_SUSPENDED) {
1294		atomic_add_unless(&parent->power.child_count, -1, 0);
1295		notify_parent = !parent->power.ignore_children;
1296	} else {
1297		spin_lock_nested(&parent->power.lock, SINGLE_DEPTH_NESTING);
1298
1299		/*
1300		 * It is invalid to put an active child under a parent that is
1301		 * not active, has runtime PM enabled and the
1302		 * 'power.ignore_children' flag unset.
1303		 */
1304		if (!parent->power.disable_depth &&
1305		    !parent->power.ignore_children &&
1306		    parent->power.runtime_status != RPM_ACTIVE) {
1307			dev_err(dev, "runtime PM trying to activate child device %s but parent (%s) is not active\n",
1308				dev_name(dev),
1309				dev_name(parent));
1310			error = -EBUSY;
1311		} else if (dev->power.runtime_status == RPM_SUSPENDED) {
1312			atomic_inc(&parent->power.child_count);
1313		}
1314
1315		spin_unlock(&parent->power.lock);
1316
1317		if (error) {
1318			status = RPM_SUSPENDED;
1319			goto out;
1320		}
1321	}
1322
1323 out_set:
1324	__update_runtime_status(dev, status);
1325	if (!error)
1326		dev->power.runtime_error = 0;
1327
1328 out:
1329	spin_unlock_irqrestore(&dev->power.lock, flags);
1330
1331	if (notify_parent)
1332		pm_request_idle(parent);
1333
1334	if (status == RPM_SUSPENDED) {
1335		int idx = device_links_read_lock();
1336
1337		rpm_put_suppliers(dev);
1338
1339		device_links_read_unlock(idx);
1340	}
1341
1342	pm_runtime_enable(dev);
1343
1344	return error;
1345}
1346EXPORT_SYMBOL_GPL(__pm_runtime_set_status);
1347
1348/**
1349 * __pm_runtime_barrier - Cancel pending requests and wait for completions.
1350 * @dev: Device to handle.
1351 *
1352 * Flush all pending requests for the device from pm_wq and wait for all
1353 * runtime PM operations involving the device in progress to complete.
1354 *
1355 * Should be called under dev->power.lock with interrupts disabled.
1356 */
1357static void __pm_runtime_barrier(struct device *dev)
1358{
1359	pm_runtime_deactivate_timer(dev);
1360
1361	if (dev->power.request_pending) {
1362		dev->power.request = RPM_REQ_NONE;
1363		spin_unlock_irq(&dev->power.lock);
1364
1365		cancel_work_sync(&dev->power.work);
1366
1367		spin_lock_irq(&dev->power.lock);
1368		dev->power.request_pending = false;
1369	}
1370
1371	if (dev->power.runtime_status == RPM_SUSPENDING ||
1372	    dev->power.runtime_status == RPM_RESUMING ||
1373	    dev->power.idle_notification) {
1374		DEFINE_WAIT(wait);
1375
1376		/* Suspend, wake-up or idle notification in progress. */
1377		for (;;) {
1378			prepare_to_wait(&dev->power.wait_queue, &wait,
1379					TASK_UNINTERRUPTIBLE);
1380			if (dev->power.runtime_status != RPM_SUSPENDING
1381			    && dev->power.runtime_status != RPM_RESUMING
1382			    && !dev->power.idle_notification)
1383				break;
1384			spin_unlock_irq(&dev->power.lock);
1385
1386			schedule();
1387
1388			spin_lock_irq(&dev->power.lock);
1389		}
1390		finish_wait(&dev->power.wait_queue, &wait);
1391	}
1392}
1393
1394/**
1395 * pm_runtime_barrier - Flush pending requests and wait for completions.
1396 * @dev: Device to handle.
1397 *
1398 * Prevent the device from being suspended by incrementing its usage counter and
1399 * if there's a pending resume request for the device, wake the device up.
1400 * Next, make sure that all pending requests for the device have been flushed
1401 * from pm_wq and wait for all runtime PM operations involving the device in
1402 * progress to complete.
1403 *
1404 * Return value:
1405 * 1, if there was a resume request pending and the device had to be woken up,
1406 * 0, otherwise
1407 */
1408int pm_runtime_barrier(struct device *dev)
1409{
1410	int retval = 0;
1411
1412	pm_runtime_get_noresume(dev);
1413	spin_lock_irq(&dev->power.lock);
1414
1415	if (dev->power.request_pending
1416	    && dev->power.request == RPM_REQ_RESUME) {
1417		rpm_resume(dev, 0);
1418		retval = 1;
1419	}
1420
1421	__pm_runtime_barrier(dev);
1422
1423	spin_unlock_irq(&dev->power.lock);
1424	pm_runtime_put_noidle(dev);
1425
1426	return retval;
1427}
1428EXPORT_SYMBOL_GPL(pm_runtime_barrier);
1429
1430/**
1431 * __pm_runtime_disable - Disable runtime PM of a device.
1432 * @dev: Device to handle.
1433 * @check_resume: If set, check if there's a resume request for the device.
1434 *
1435 * Increment power.disable_depth for the device and if it was zero previously,
1436 * cancel all pending runtime PM requests for the device and wait for all
1437 * operations in progress to complete.  The device can be either active or
1438 * suspended after its runtime PM has been disabled.
1439 *
1440 * If @check_resume is set and there's a resume request pending when
1441 * __pm_runtime_disable() is called and power.disable_depth is zero, the
1442 * function will wake up the device before disabling its runtime PM.
1443 */
1444void __pm_runtime_disable(struct device *dev, bool check_resume)
1445{
1446	spin_lock_irq(&dev->power.lock);
1447
1448	if (dev->power.disable_depth > 0) {
1449		dev->power.disable_depth++;
1450		goto out;
1451	}
1452
1453	/*
1454	 * Wake up the device if there's a resume request pending, because that
1455	 * means there probably is some I/O to process and disabling runtime PM
1456	 * shouldn't prevent the device from processing the I/O.
1457	 */
1458	if (check_resume && dev->power.request_pending &&
1459	    dev->power.request == RPM_REQ_RESUME) {
1460		/*
1461		 * Prevent suspends and idle notifications from being carried
1462		 * out after we have woken up the device.
1463		 */
1464		pm_runtime_get_noresume(dev);
1465
1466		rpm_resume(dev, 0);
1467
1468		pm_runtime_put_noidle(dev);
1469	}
1470
1471	/* Update time accounting before disabling PM-runtime. */
1472	update_pm_runtime_accounting(dev);
1473
1474	if (!dev->power.disable_depth++) {
1475		__pm_runtime_barrier(dev);
1476		dev->power.last_status = dev->power.runtime_status;
1477	}
1478
1479 out:
1480	spin_unlock_irq(&dev->power.lock);
1481}
1482EXPORT_SYMBOL_GPL(__pm_runtime_disable);
1483
1484/**
1485 * pm_runtime_enable - Enable runtime PM of a device.
1486 * @dev: Device to handle.
1487 */
1488void pm_runtime_enable(struct device *dev)
1489{
1490	unsigned long flags;
1491
1492	spin_lock_irqsave(&dev->power.lock, flags);
1493
1494	if (!dev->power.disable_depth) {
 
 
 
 
 
 
1495		dev_warn(dev, "Unbalanced %s!\n", __func__);
1496		goto out;
1497	}
1498
1499	if (--dev->power.disable_depth > 0)
1500		goto out;
1501
1502	dev->power.last_status = RPM_INVALID;
1503	dev->power.accounting_timestamp = ktime_get_mono_fast_ns();
1504
1505	if (dev->power.runtime_status == RPM_SUSPENDED &&
1506	    !dev->power.ignore_children &&
1507	    atomic_read(&dev->power.child_count) > 0)
1508		dev_warn(dev, "Enabling runtime PM for inactive device with active children\n");
1509
1510out:
1511	spin_unlock_irqrestore(&dev->power.lock, flags);
1512}
1513EXPORT_SYMBOL_GPL(pm_runtime_enable);
1514
1515static void pm_runtime_disable_action(void *data)
1516{
1517	pm_runtime_dont_use_autosuspend(data);
1518	pm_runtime_disable(data);
1519}
1520
1521/**
1522 * devm_pm_runtime_enable - devres-enabled version of pm_runtime_enable.
1523 *
1524 * NOTE: this will also handle calling pm_runtime_dont_use_autosuspend() for
1525 * you at driver exit time if needed.
1526 *
1527 * @dev: Device to handle.
1528 */
1529int devm_pm_runtime_enable(struct device *dev)
1530{
1531	pm_runtime_enable(dev);
1532
1533	return devm_add_action_or_reset(dev, pm_runtime_disable_action, dev);
1534}
1535EXPORT_SYMBOL_GPL(devm_pm_runtime_enable);
1536
1537/**
1538 * pm_runtime_forbid - Block runtime PM of a device.
1539 * @dev: Device to handle.
1540 *
1541 * Increase the device's usage count and clear its power.runtime_auto flag,
1542 * so that it cannot be suspended at run time until pm_runtime_allow() is called
1543 * for it.
1544 */
1545void pm_runtime_forbid(struct device *dev)
1546{
1547	spin_lock_irq(&dev->power.lock);
1548	if (!dev->power.runtime_auto)
1549		goto out;
1550
1551	dev->power.runtime_auto = false;
1552	atomic_inc(&dev->power.usage_count);
1553	rpm_resume(dev, 0);
1554
1555 out:
1556	spin_unlock_irq(&dev->power.lock);
1557}
1558EXPORT_SYMBOL_GPL(pm_runtime_forbid);
1559
1560/**
1561 * pm_runtime_allow - Unblock runtime PM of a device.
1562 * @dev: Device to handle.
1563 *
1564 * Decrease the device's usage count and set its power.runtime_auto flag.
1565 */
1566void pm_runtime_allow(struct device *dev)
1567{
1568	int ret;
1569
1570	spin_lock_irq(&dev->power.lock);
1571	if (dev->power.runtime_auto)
1572		goto out;
1573
1574	dev->power.runtime_auto = true;
1575	ret = rpm_drop_usage_count(dev);
1576	if (ret == 0)
1577		rpm_idle(dev, RPM_AUTO | RPM_ASYNC);
1578	else if (ret > 0)
1579		trace_rpm_usage_rcuidle(dev, RPM_AUTO | RPM_ASYNC);
1580
1581 out:
1582	spin_unlock_irq(&dev->power.lock);
1583}
1584EXPORT_SYMBOL_GPL(pm_runtime_allow);
1585
1586/**
1587 * pm_runtime_no_callbacks - Ignore runtime PM callbacks for a device.
1588 * @dev: Device to handle.
1589 *
1590 * Set the power.no_callbacks flag, which tells the PM core that this
1591 * device is power-managed through its parent and has no runtime PM
1592 * callbacks of its own.  The runtime sysfs attributes will be removed.
1593 */
1594void pm_runtime_no_callbacks(struct device *dev)
1595{
1596	spin_lock_irq(&dev->power.lock);
1597	dev->power.no_callbacks = 1;
1598	spin_unlock_irq(&dev->power.lock);
1599	if (device_is_registered(dev))
1600		rpm_sysfs_remove(dev);
1601}
1602EXPORT_SYMBOL_GPL(pm_runtime_no_callbacks);
1603
1604/**
1605 * pm_runtime_irq_safe - Leave interrupts disabled during callbacks.
1606 * @dev: Device to handle
1607 *
1608 * Set the power.irq_safe flag, which tells the PM core that the
1609 * ->runtime_suspend() and ->runtime_resume() callbacks for this device should
1610 * always be invoked with the spinlock held and interrupts disabled.  It also
1611 * causes the parent's usage counter to be permanently incremented, preventing
1612 * the parent from runtime suspending -- otherwise an irq-safe child might have
1613 * to wait for a non-irq-safe parent.
1614 */
1615void pm_runtime_irq_safe(struct device *dev)
1616{
1617	if (dev->parent)
1618		pm_runtime_get_sync(dev->parent);
1619
1620	spin_lock_irq(&dev->power.lock);
1621	dev->power.irq_safe = 1;
1622	spin_unlock_irq(&dev->power.lock);
1623}
1624EXPORT_SYMBOL_GPL(pm_runtime_irq_safe);
1625
1626/**
1627 * update_autosuspend - Handle a change to a device's autosuspend settings.
1628 * @dev: Device to handle.
1629 * @old_delay: The former autosuspend_delay value.
1630 * @old_use: The former use_autosuspend value.
1631 *
1632 * Prevent runtime suspend if the new delay is negative and use_autosuspend is
1633 * set; otherwise allow it.  Send an idle notification if suspends are allowed.
1634 *
1635 * This function must be called under dev->power.lock with interrupts disabled.
1636 */
1637static void update_autosuspend(struct device *dev, int old_delay, int old_use)
1638{
1639	int delay = dev->power.autosuspend_delay;
1640
1641	/* Should runtime suspend be prevented now? */
1642	if (dev->power.use_autosuspend && delay < 0) {
1643
1644		/* If it used to be allowed then prevent it. */
1645		if (!old_use || old_delay >= 0) {
1646			atomic_inc(&dev->power.usage_count);
1647			rpm_resume(dev, 0);
1648		} else {
1649			trace_rpm_usage_rcuidle(dev, 0);
1650		}
1651	}
1652
1653	/* Runtime suspend should be allowed now. */
1654	else {
1655
1656		/* If it used to be prevented then allow it. */
1657		if (old_use && old_delay < 0)
1658			atomic_dec(&dev->power.usage_count);
1659
1660		/* Maybe we can autosuspend now. */
1661		rpm_idle(dev, RPM_AUTO);
1662	}
1663}
1664
1665/**
1666 * pm_runtime_set_autosuspend_delay - Set a device's autosuspend_delay value.
1667 * @dev: Device to handle.
1668 * @delay: Value of the new delay in milliseconds.
1669 *
1670 * Set the device's power.autosuspend_delay value.  If it changes to negative
1671 * and the power.use_autosuspend flag is set, prevent runtime suspends.  If it
1672 * changes the other way, allow runtime suspends.
1673 */
1674void pm_runtime_set_autosuspend_delay(struct device *dev, int delay)
1675{
1676	int old_delay, old_use;
1677
1678	spin_lock_irq(&dev->power.lock);
1679	old_delay = dev->power.autosuspend_delay;
1680	old_use = dev->power.use_autosuspend;
1681	dev->power.autosuspend_delay = delay;
1682	update_autosuspend(dev, old_delay, old_use);
1683	spin_unlock_irq(&dev->power.lock);
1684}
1685EXPORT_SYMBOL_GPL(pm_runtime_set_autosuspend_delay);
1686
1687/**
1688 * __pm_runtime_use_autosuspend - Set a device's use_autosuspend flag.
1689 * @dev: Device to handle.
1690 * @use: New value for use_autosuspend.
1691 *
1692 * Set the device's power.use_autosuspend flag, and allow or prevent runtime
1693 * suspends as needed.
1694 */
1695void __pm_runtime_use_autosuspend(struct device *dev, bool use)
1696{
1697	int old_delay, old_use;
1698
1699	spin_lock_irq(&dev->power.lock);
1700	old_delay = dev->power.autosuspend_delay;
1701	old_use = dev->power.use_autosuspend;
1702	dev->power.use_autosuspend = use;
1703	update_autosuspend(dev, old_delay, old_use);
1704	spin_unlock_irq(&dev->power.lock);
1705}
1706EXPORT_SYMBOL_GPL(__pm_runtime_use_autosuspend);
1707
1708/**
1709 * pm_runtime_init - Initialize runtime PM fields in given device object.
1710 * @dev: Device object to initialize.
1711 */
1712void pm_runtime_init(struct device *dev)
1713{
1714	dev->power.runtime_status = RPM_SUSPENDED;
1715	dev->power.last_status = RPM_INVALID;
1716	dev->power.idle_notification = false;
1717
1718	dev->power.disable_depth = 1;
1719	atomic_set(&dev->power.usage_count, 0);
1720
1721	dev->power.runtime_error = 0;
1722
1723	atomic_set(&dev->power.child_count, 0);
1724	pm_suspend_ignore_children(dev, false);
1725	dev->power.runtime_auto = true;
1726
1727	dev->power.request_pending = false;
1728	dev->power.request = RPM_REQ_NONE;
1729	dev->power.deferred_resume = false;
1730	dev->power.needs_force_resume = 0;
1731	INIT_WORK(&dev->power.work, pm_runtime_work);
1732
1733	dev->power.timer_expires = 0;
1734	hrtimer_init(&dev->power.suspend_timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
1735	dev->power.suspend_timer.function = pm_suspend_timer_fn;
1736
1737	init_waitqueue_head(&dev->power.wait_queue);
1738}
1739
1740/**
1741 * pm_runtime_reinit - Re-initialize runtime PM fields in given device object.
1742 * @dev: Device object to re-initialize.
1743 */
1744void pm_runtime_reinit(struct device *dev)
1745{
1746	if (!pm_runtime_enabled(dev)) {
1747		if (dev->power.runtime_status == RPM_ACTIVE)
1748			pm_runtime_set_suspended(dev);
1749		if (dev->power.irq_safe) {
1750			spin_lock_irq(&dev->power.lock);
1751			dev->power.irq_safe = 0;
1752			spin_unlock_irq(&dev->power.lock);
1753			if (dev->parent)
1754				pm_runtime_put(dev->parent);
1755		}
1756	}
1757}
1758
1759/**
1760 * pm_runtime_remove - Prepare for removing a device from device hierarchy.
1761 * @dev: Device object being removed from device hierarchy.
1762 */
1763void pm_runtime_remove(struct device *dev)
1764{
1765	__pm_runtime_disable(dev, false);
1766	pm_runtime_reinit(dev);
1767}
1768
1769/**
1770 * pm_runtime_get_suppliers - Resume and reference-count supplier devices.
1771 * @dev: Consumer device.
1772 */
1773void pm_runtime_get_suppliers(struct device *dev)
1774{
1775	struct device_link *link;
1776	int idx;
1777
1778	idx = device_links_read_lock();
1779
1780	list_for_each_entry_rcu(link, &dev->links.suppliers, c_node,
1781				device_links_read_lock_held())
1782		if (link->flags & DL_FLAG_PM_RUNTIME) {
1783			link->supplier_preactivated = true;
1784			pm_runtime_get_sync(link->supplier);
 
1785		}
1786
1787	device_links_read_unlock(idx);
1788}
1789
1790/**
1791 * pm_runtime_put_suppliers - Drop references to supplier devices.
1792 * @dev: Consumer device.
1793 */
1794void pm_runtime_put_suppliers(struct device *dev)
1795{
1796	struct device_link *link;
 
 
1797	int idx;
1798
1799	idx = device_links_read_lock();
1800
1801	list_for_each_entry_rcu(link, &dev->links.suppliers, c_node,
1802				device_links_read_lock_held())
1803		if (link->supplier_preactivated) {
1804			link->supplier_preactivated = false;
1805			pm_runtime_put(link->supplier);
 
 
 
 
 
1806		}
1807
1808	device_links_read_unlock(idx);
1809}
1810
1811void pm_runtime_new_link(struct device *dev)
1812{
1813	spin_lock_irq(&dev->power.lock);
1814	dev->power.links_count++;
1815	spin_unlock_irq(&dev->power.lock);
1816}
1817
1818static void pm_runtime_drop_link_count(struct device *dev)
1819{
1820	spin_lock_irq(&dev->power.lock);
1821	WARN_ON(dev->power.links_count == 0);
1822	dev->power.links_count--;
1823	spin_unlock_irq(&dev->power.lock);
1824}
1825
1826/**
1827 * pm_runtime_drop_link - Prepare for device link removal.
1828 * @link: Device link going away.
1829 *
1830 * Drop the link count of the consumer end of @link and decrement the supplier
1831 * device's runtime PM usage counter as many times as needed to drop all of the
1832 * PM runtime reference to it from the consumer.
1833 */
1834void pm_runtime_drop_link(struct device_link *link)
1835{
1836	if (!(link->flags & DL_FLAG_PM_RUNTIME))
1837		return;
1838
1839	pm_runtime_drop_link_count(link->consumer);
1840	pm_runtime_release_supplier(link);
1841	pm_request_idle(link->supplier);
 
1842}
1843
1844static bool pm_runtime_need_not_resume(struct device *dev)
1845{
1846	return atomic_read(&dev->power.usage_count) <= 1 &&
1847		(atomic_read(&dev->power.child_count) == 0 ||
1848		 dev->power.ignore_children);
1849}
1850
1851/**
1852 * pm_runtime_force_suspend - Force a device into suspend state if needed.
1853 * @dev: Device to suspend.
1854 *
1855 * Disable runtime PM so we safely can check the device's runtime PM status and
1856 * if it is active, invoke its ->runtime_suspend callback to suspend it and
1857 * change its runtime PM status field to RPM_SUSPENDED.  Also, if the device's
1858 * usage and children counters don't indicate that the device was in use before
1859 * the system-wide transition under way, decrement its parent's children counter
1860 * (if there is a parent).  Keep runtime PM disabled to preserve the state
1861 * unless we encounter errors.
1862 *
1863 * Typically this function may be invoked from a system suspend callback to make
1864 * sure the device is put into low power state and it should only be used during
1865 * system-wide PM transitions to sleep states.  It assumes that the analogous
1866 * pm_runtime_force_resume() will be used to resume the device.
1867 */
1868int pm_runtime_force_suspend(struct device *dev)
1869{
1870	int (*callback)(struct device *);
1871	int ret;
1872
1873	pm_runtime_disable(dev);
1874	if (pm_runtime_status_suspended(dev))
1875		return 0;
1876
1877	callback = RPM_GET_CALLBACK(dev, runtime_suspend);
1878
1879	dev_pm_enable_wake_irq_check(dev, true);
1880	ret = callback ? callback(dev) : 0;
1881	if (ret)
1882		goto err;
1883
1884	dev_pm_enable_wake_irq_complete(dev);
1885
1886	/*
1887	 * If the device can stay in suspend after the system-wide transition
1888	 * to the working state that will follow, drop the children counter of
1889	 * its parent, but set its status to RPM_SUSPENDED anyway in case this
1890	 * function will be called again for it in the meantime.
1891	 */
1892	if (pm_runtime_need_not_resume(dev)) {
1893		pm_runtime_set_suspended(dev);
1894	} else {
1895		__update_runtime_status(dev, RPM_SUSPENDED);
1896		dev->power.needs_force_resume = 1;
1897	}
1898
1899	return 0;
1900
1901err:
1902	dev_pm_disable_wake_irq_check(dev, true);
1903	pm_runtime_enable(dev);
1904	return ret;
1905}
1906EXPORT_SYMBOL_GPL(pm_runtime_force_suspend);
1907
1908/**
1909 * pm_runtime_force_resume - Force a device into resume state if needed.
1910 * @dev: Device to resume.
1911 *
1912 * Prior invoking this function we expect the user to have brought the device
1913 * into low power state by a call to pm_runtime_force_suspend(). Here we reverse
1914 * those actions and bring the device into full power, if it is expected to be
1915 * used on system resume.  In the other case, we defer the resume to be managed
1916 * via runtime PM.
1917 *
1918 * Typically this function may be invoked from a system resume callback.
1919 */
1920int pm_runtime_force_resume(struct device *dev)
1921{
1922	int (*callback)(struct device *);
1923	int ret = 0;
1924
1925	if (!pm_runtime_status_suspended(dev) || !dev->power.needs_force_resume)
1926		goto out;
1927
1928	/*
1929	 * The value of the parent's children counter is correct already, so
1930	 * just update the status of the device.
1931	 */
1932	__update_runtime_status(dev, RPM_ACTIVE);
1933
1934	callback = RPM_GET_CALLBACK(dev, runtime_resume);
1935
1936	dev_pm_disable_wake_irq_check(dev, false);
1937	ret = callback ? callback(dev) : 0;
1938	if (ret) {
1939		pm_runtime_set_suspended(dev);
1940		dev_pm_enable_wake_irq_check(dev, false);
1941		goto out;
1942	}
1943
1944	pm_runtime_mark_last_busy(dev);
1945out:
1946	dev->power.needs_force_resume = 0;
1947	pm_runtime_enable(dev);
1948	return ret;
1949}
1950EXPORT_SYMBOL_GPL(pm_runtime_force_resume);