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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 <linux/pm_wakeirq.h>
14 #include <trace/events/rpm.h>
15 #include "power.h"
16 
17 typedef int (*pm_callback_t)(struct device *);
18 
__rpm_get_callback(struct device * dev,size_t cb_offset)19 static pm_callback_t __rpm_get_callback(struct device *dev, size_t cb_offset)
20 {
21 	pm_callback_t cb;
22 	const struct dev_pm_ops *ops;
23 
24 	if (dev->pm_domain)
25 		ops = &dev->pm_domain->ops;
26 	else if (dev->type && dev->type->pm)
27 		ops = dev->type->pm;
28 	else if (dev->class && dev->class->pm)
29 		ops = dev->class->pm;
30 	else if (dev->bus && dev->bus->pm)
31 		ops = dev->bus->pm;
32 	else
33 		ops = NULL;
34 
35 	if (ops)
36 		cb = *(pm_callback_t *)((void *)ops + cb_offset);
37 	else
38 		cb = NULL;
39 
40 	if (!cb && dev->driver && dev->driver->pm)
41 		cb = *(pm_callback_t *)((void *)dev->driver->pm + cb_offset);
42 
43 	return cb;
44 }
45 
46 #define RPM_GET_CALLBACK(dev, callback) \
47 		__rpm_get_callback(dev, offsetof(struct dev_pm_ops, callback))
48 
49 static int rpm_resume(struct device *dev, int rpmflags);
50 static int rpm_suspend(struct device *dev, int rpmflags);
51 
52 /**
53  * update_pm_runtime_accounting - Update the time accounting of power states
54  * @dev: Device to update the accounting for
55  *
56  * In order to be able to have time accounting of the various power states
57  * (as used by programs such as PowerTOP to show the effectiveness of runtime
58  * PM), we need to track the time spent in each state.
59  * update_pm_runtime_accounting must be called each time before the
60  * runtime_status field is updated, to account the time in the old state
61  * correctly.
62  */
update_pm_runtime_accounting(struct device * dev)63 void update_pm_runtime_accounting(struct device *dev)
64 {
65 	unsigned long now = jiffies;
66 	unsigned long delta;
67 
68 	delta = now - dev->power.accounting_timestamp;
69 
70 	dev->power.accounting_timestamp = now;
71 
72 	if (dev->power.disable_depth > 0)
73 		return;
74 
75 	if (dev->power.runtime_status == RPM_SUSPENDED)
76 		dev->power.suspended_jiffies += delta;
77 	else
78 		dev->power.active_jiffies += delta;
79 }
80 
__update_runtime_status(struct device * dev,enum rpm_status status)81 static void __update_runtime_status(struct device *dev, enum rpm_status status)
82 {
83 	update_pm_runtime_accounting(dev);
84 	dev->power.runtime_status = status;
85 }
86 
87 /**
88  * pm_runtime_deactivate_timer - Deactivate given device's suspend timer.
89  * @dev: Device to handle.
90  */
pm_runtime_deactivate_timer(struct device * dev)91 static void pm_runtime_deactivate_timer(struct device *dev)
92 {
93 	if (dev->power.timer_expires > 0) {
94 		del_timer(&dev->power.suspend_timer);
95 		dev->power.timer_expires = 0;
96 	}
97 }
98 
99 /**
100  * pm_runtime_cancel_pending - Deactivate suspend timer and cancel requests.
101  * @dev: Device to handle.
102  */
pm_runtime_cancel_pending(struct device * dev)103 static void pm_runtime_cancel_pending(struct device *dev)
104 {
105 	pm_runtime_deactivate_timer(dev);
106 	/*
107 	 * In case there's a request pending, make sure its work function will
108 	 * return without doing anything.
109 	 */
110 	dev->power.request = RPM_REQ_NONE;
111 }
112 
113 /*
114  * pm_runtime_autosuspend_expiration - Get a device's autosuspend-delay expiration time.
115  * @dev: Device to handle.
116  *
117  * Compute the autosuspend-delay expiration time based on the device's
118  * power.last_busy time.  If the delay has already expired or is disabled
119  * (negative) or the power.use_autosuspend flag isn't set, return 0.
120  * Otherwise return the expiration time in jiffies (adjusted to be nonzero).
121  *
122  * This function may be called either with or without dev->power.lock held.
123  * Either way it can be racy, since power.last_busy may be updated at any time.
124  */
pm_runtime_autosuspend_expiration(struct device * dev)125 unsigned long pm_runtime_autosuspend_expiration(struct device *dev)
126 {
127 	int autosuspend_delay;
128 	long elapsed;
129 	unsigned long last_busy;
130 	unsigned long expires = 0;
131 
132 	if (!dev->power.use_autosuspend)
133 		goto out;
134 
135 	autosuspend_delay = ACCESS_ONCE(dev->power.autosuspend_delay);
136 	if (autosuspend_delay < 0)
137 		goto out;
138 
139 	last_busy = ACCESS_ONCE(dev->power.last_busy);
140 	elapsed = jiffies - last_busy;
141 	if (elapsed < 0)
142 		goto out;	/* jiffies has wrapped around. */
143 
144 	/*
145 	 * If the autosuspend_delay is >= 1 second, align the timer by rounding
146 	 * up to the nearest second.
147 	 */
148 	expires = last_busy + msecs_to_jiffies(autosuspend_delay);
149 	if (autosuspend_delay >= 1000)
150 		expires = round_jiffies(expires);
151 	expires += !expires;
152 	if (elapsed >= expires - last_busy)
153 		expires = 0;	/* Already expired. */
154 
155  out:
156 	return expires;
157 }
158 EXPORT_SYMBOL_GPL(pm_runtime_autosuspend_expiration);
159 
dev_memalloc_noio(struct device * dev,void * data)160 static int dev_memalloc_noio(struct device *dev, void *data)
161 {
162 	return dev->power.memalloc_noio;
163 }
164 
165 /*
166  * pm_runtime_set_memalloc_noio - Set a device's memalloc_noio flag.
167  * @dev: Device to handle.
168  * @enable: True for setting the flag and False for clearing the flag.
169  *
170  * Set the flag for all devices in the path from the device to the
171  * root device in the device tree if @enable is true, otherwise clear
172  * the flag for devices in the path whose siblings don't set the flag.
173  *
174  * The function should only be called by block device, or network
175  * device driver for solving the deadlock problem during runtime
176  * resume/suspend:
177  *
178  *     If memory allocation with GFP_KERNEL is called inside runtime
179  *     resume/suspend callback of any one of its ancestors(or the
180  *     block device itself), the deadlock may be triggered inside the
181  *     memory allocation since it might not complete until the block
182  *     device becomes active and the involed page I/O finishes. The
183  *     situation is pointed out first by Alan Stern. Network device
184  *     are involved in iSCSI kind of situation.
185  *
186  * The lock of dev_hotplug_mutex is held in the function for handling
187  * hotplug race because pm_runtime_set_memalloc_noio() may be called
188  * in async probe().
189  *
190  * The function should be called between device_add() and device_del()
191  * on the affected device(block/network device).
192  */
pm_runtime_set_memalloc_noio(struct device * dev,bool enable)193 void pm_runtime_set_memalloc_noio(struct device *dev, bool enable)
194 {
195 	static DEFINE_MUTEX(dev_hotplug_mutex);
196 
197 	mutex_lock(&dev_hotplug_mutex);
198 	for (;;) {
199 		bool enabled;
200 
201 		/* hold power lock since bitfield is not SMP-safe. */
202 		spin_lock_irq(&dev->power.lock);
203 		enabled = dev->power.memalloc_noio;
204 		dev->power.memalloc_noio = enable;
205 		spin_unlock_irq(&dev->power.lock);
206 
207 		/*
208 		 * not need to enable ancestors any more if the device
209 		 * has been enabled.
210 		 */
211 		if (enabled && enable)
212 			break;
213 
214 		dev = dev->parent;
215 
216 		/*
217 		 * clear flag of the parent device only if all the
218 		 * children don't set the flag because ancestor's
219 		 * flag was set by any one of the descendants.
220 		 */
221 		if (!dev || (!enable &&
222 			     device_for_each_child(dev, NULL,
223 						   dev_memalloc_noio)))
224 			break;
225 	}
226 	mutex_unlock(&dev_hotplug_mutex);
227 }
228 EXPORT_SYMBOL_GPL(pm_runtime_set_memalloc_noio);
229 
230 /**
231  * rpm_check_suspend_allowed - Test whether a device may be suspended.
232  * @dev: Device to test.
233  */
rpm_check_suspend_allowed(struct device * dev)234 static int rpm_check_suspend_allowed(struct device *dev)
235 {
236 	int retval = 0;
237 
238 	if (dev->power.runtime_error)
239 		retval = -EINVAL;
240 	else if (dev->power.disable_depth > 0)
241 		retval = -EACCES;
242 	else if (atomic_read(&dev->power.usage_count) > 0)
243 		retval = -EAGAIN;
244 	else if (!pm_children_suspended(dev))
245 		retval = -EBUSY;
246 
247 	/* Pending resume requests take precedence over suspends. */
248 	else if ((dev->power.deferred_resume
249 			&& dev->power.runtime_status == RPM_SUSPENDING)
250 	    || (dev->power.request_pending
251 			&& dev->power.request == RPM_REQ_RESUME))
252 		retval = -EAGAIN;
253 	else if (__dev_pm_qos_read_value(dev) < 0)
254 		retval = -EPERM;
255 	else if (dev->power.runtime_status == RPM_SUSPENDED)
256 		retval = 1;
257 
258 	return retval;
259 }
260 
261 /**
262  * __rpm_callback - Run a given runtime PM callback for a given device.
263  * @cb: Runtime PM callback to run.
264  * @dev: Device to run the callback for.
265  */
__rpm_callback(int (* cb)(struct device *),struct device * dev)266 static int __rpm_callback(int (*cb)(struct device *), struct device *dev)
267 	__releases(&dev->power.lock) __acquires(&dev->power.lock)
268 {
269 	int retval;
270 
271 	if (dev->power.irq_safe)
272 		spin_unlock(&dev->power.lock);
273 	else
274 		spin_unlock_irq(&dev->power.lock);
275 
276 	retval = cb(dev);
277 
278 	if (dev->power.irq_safe)
279 		spin_lock(&dev->power.lock);
280 	else
281 		spin_lock_irq(&dev->power.lock);
282 
283 	return retval;
284 }
285 
286 /**
287  * rpm_idle - Notify device bus type if the device can be suspended.
288  * @dev: Device to notify the bus type about.
289  * @rpmflags: Flag bits.
290  *
291  * Check if the device's runtime PM status allows it to be suspended.  If
292  * another idle notification has been started earlier, return immediately.  If
293  * the RPM_ASYNC flag is set then queue an idle-notification request; otherwise
294  * run the ->runtime_idle() callback directly. If the ->runtime_idle callback
295  * doesn't exist or if it returns 0, call rpm_suspend with the RPM_AUTO flag.
296  *
297  * This function must be called under dev->power.lock with interrupts disabled.
298  */
rpm_idle(struct device * dev,int rpmflags)299 static int rpm_idle(struct device *dev, int rpmflags)
300 {
301 	int (*callback)(struct device *);
302 	int retval;
303 
304 	trace_rpm_idle_rcuidle(dev, rpmflags);
305 	retval = rpm_check_suspend_allowed(dev);
306 	if (retval < 0)
307 		;	/* Conditions are wrong. */
308 
309 	/* Idle notifications are allowed only in the RPM_ACTIVE state. */
310 	else if (dev->power.runtime_status != RPM_ACTIVE)
311 		retval = -EAGAIN;
312 
313 	/*
314 	 * Any pending request other than an idle notification takes
315 	 * precedence over us, except that the timer may be running.
316 	 */
317 	else if (dev->power.request_pending &&
318 	    dev->power.request > RPM_REQ_IDLE)
319 		retval = -EAGAIN;
320 
321 	/* Act as though RPM_NOWAIT is always set. */
322 	else if (dev->power.idle_notification)
323 		retval = -EINPROGRESS;
324 	if (retval)
325 		goto out;
326 
327 	/* Pending requests need to be canceled. */
328 	dev->power.request = RPM_REQ_NONE;
329 
330 	if (dev->power.no_callbacks)
331 		goto out;
332 
333 	/* Carry out an asynchronous or a synchronous idle notification. */
334 	if (rpmflags & RPM_ASYNC) {
335 		dev->power.request = RPM_REQ_IDLE;
336 		if (!dev->power.request_pending) {
337 			dev->power.request_pending = true;
338 			queue_work(pm_wq, &dev->power.work);
339 		}
340 		trace_rpm_return_int_rcuidle(dev, _THIS_IP_, 0);
341 		return 0;
342 	}
343 
344 	dev->power.idle_notification = true;
345 
346 	callback = RPM_GET_CALLBACK(dev, runtime_idle);
347 
348 	if (callback)
349 		retval = __rpm_callback(callback, dev);
350 
351 	dev->power.idle_notification = false;
352 	wake_up_all(&dev->power.wait_queue);
353 
354  out:
355 	trace_rpm_return_int_rcuidle(dev, _THIS_IP_, retval);
356 	return retval ? retval : rpm_suspend(dev, rpmflags | RPM_AUTO);
357 }
358 
359 /**
360  * rpm_callback - Run a given runtime PM callback for a given device.
361  * @cb: Runtime PM callback to run.
362  * @dev: Device to run the callback for.
363  */
rpm_callback(int (* cb)(struct device *),struct device * dev)364 static int rpm_callback(int (*cb)(struct device *), struct device *dev)
365 {
366 	int retval;
367 
368 	if (!cb)
369 		return -ENOSYS;
370 
371 	if (dev->power.memalloc_noio) {
372 		unsigned int noio_flag;
373 
374 		/*
375 		 * Deadlock might be caused if memory allocation with
376 		 * GFP_KERNEL happens inside runtime_suspend and
377 		 * runtime_resume callbacks of one block device's
378 		 * ancestor or the block device itself. Network
379 		 * device might be thought as part of iSCSI block
380 		 * device, so network device and its ancestor should
381 		 * be marked as memalloc_noio too.
382 		 */
383 		noio_flag = memalloc_noio_save();
384 		retval = __rpm_callback(cb, dev);
385 		memalloc_noio_restore(noio_flag);
386 	} else {
387 		retval = __rpm_callback(cb, dev);
388 	}
389 
390 	dev->power.runtime_error = retval;
391 	return retval != -EACCES ? retval : -EIO;
392 }
393 
394 /**
395  * rpm_suspend - Carry out runtime suspend of given device.
396  * @dev: Device to suspend.
397  * @rpmflags: Flag bits.
398  *
399  * Check if the device's runtime PM status allows it to be suspended.
400  * Cancel a pending idle notification, autosuspend or suspend. If
401  * another suspend has been started earlier, either return immediately
402  * or wait for it to finish, depending on the RPM_NOWAIT and RPM_ASYNC
403  * flags. If the RPM_ASYNC flag is set then queue a suspend request;
404  * otherwise run the ->runtime_suspend() callback directly. When
405  * ->runtime_suspend succeeded, if a deferred resume was requested while
406  * the callback was running then carry it out, otherwise send an idle
407  * notification for its parent (if the suspend succeeded and both
408  * ignore_children of parent->power and irq_safe of dev->power are not set).
409  * If ->runtime_suspend failed with -EAGAIN or -EBUSY, and if the RPM_AUTO
410  * flag is set and the next autosuspend-delay expiration time is in the
411  * future, schedule another autosuspend attempt.
412  *
413  * This function must be called under dev->power.lock with interrupts disabled.
414  */
rpm_suspend(struct device * dev,int rpmflags)415 static int rpm_suspend(struct device *dev, int rpmflags)
416 	__releases(&dev->power.lock) __acquires(&dev->power.lock)
417 {
418 	int (*callback)(struct device *);
419 	struct device *parent = NULL;
420 	int retval;
421 
422 	trace_rpm_suspend_rcuidle(dev, rpmflags);
423 
424  repeat:
425 	retval = rpm_check_suspend_allowed(dev);
426 
427 	if (retval < 0)
428 		;	/* Conditions are wrong. */
429 
430 	/* Synchronous suspends are not allowed in the RPM_RESUMING state. */
431 	else if (dev->power.runtime_status == RPM_RESUMING &&
432 	    !(rpmflags & RPM_ASYNC))
433 		retval = -EAGAIN;
434 	if (retval)
435 		goto out;
436 
437 	/* If the autosuspend_delay time hasn't expired yet, reschedule. */
438 	if ((rpmflags & RPM_AUTO)
439 	    && dev->power.runtime_status != RPM_SUSPENDING) {
440 		unsigned long expires = pm_runtime_autosuspend_expiration(dev);
441 
442 		if (expires != 0) {
443 			/* Pending requests need to be canceled. */
444 			dev->power.request = RPM_REQ_NONE;
445 
446 			/*
447 			 * Optimization: If the timer is already running and is
448 			 * set to expire at or before the autosuspend delay,
449 			 * avoid the overhead of resetting it.  Just let it
450 			 * expire; pm_suspend_timer_fn() will take care of the
451 			 * rest.
452 			 */
453 			if (!(dev->power.timer_expires && time_before_eq(
454 			    dev->power.timer_expires, expires))) {
455 				dev->power.timer_expires = expires;
456 				mod_timer(&dev->power.suspend_timer, expires);
457 			}
458 			dev->power.timer_autosuspends = 1;
459 			goto out;
460 		}
461 	}
462 
463 	/* Other scheduled or pending requests need to be canceled. */
464 	pm_runtime_cancel_pending(dev);
465 
466 	if (dev->power.runtime_status == RPM_SUSPENDING) {
467 		DEFINE_WAIT(wait);
468 
469 		if (rpmflags & (RPM_ASYNC | RPM_NOWAIT)) {
470 			retval = -EINPROGRESS;
471 			goto out;
472 		}
473 
474 		if (dev->power.irq_safe) {
475 			spin_unlock(&dev->power.lock);
476 
477 			cpu_relax();
478 
479 			spin_lock(&dev->power.lock);
480 			goto repeat;
481 		}
482 
483 		/* Wait for the other suspend running in parallel with us. */
484 		for (;;) {
485 			prepare_to_wait(&dev->power.wait_queue, &wait,
486 					TASK_UNINTERRUPTIBLE);
487 			if (dev->power.runtime_status != RPM_SUSPENDING)
488 				break;
489 
490 			spin_unlock_irq(&dev->power.lock);
491 
492 			schedule();
493 
494 			spin_lock_irq(&dev->power.lock);
495 		}
496 		finish_wait(&dev->power.wait_queue, &wait);
497 		goto repeat;
498 	}
499 
500 	if (dev->power.no_callbacks)
501 		goto no_callback;	/* Assume success. */
502 
503 	/* Carry out an asynchronous or a synchronous suspend. */
504 	if (rpmflags & RPM_ASYNC) {
505 		dev->power.request = (rpmflags & RPM_AUTO) ?
506 		    RPM_REQ_AUTOSUSPEND : RPM_REQ_SUSPEND;
507 		if (!dev->power.request_pending) {
508 			dev->power.request_pending = true;
509 			queue_work(pm_wq, &dev->power.work);
510 		}
511 		goto out;
512 	}
513 
514 	__update_runtime_status(dev, RPM_SUSPENDING);
515 
516 	callback = RPM_GET_CALLBACK(dev, runtime_suspend);
517 
518 	dev_pm_enable_wake_irq_check(dev, true);
519 	retval = rpm_callback(callback, dev);
520 	if (retval)
521 		goto fail;
522 
523  no_callback:
524 	__update_runtime_status(dev, RPM_SUSPENDED);
525 	pm_runtime_deactivate_timer(dev);
526 
527 	if (dev->parent) {
528 		parent = dev->parent;
529 		atomic_add_unless(&parent->power.child_count, -1, 0);
530 	}
531 	wake_up_all(&dev->power.wait_queue);
532 
533 	if (dev->power.deferred_resume) {
534 		dev->power.deferred_resume = false;
535 		rpm_resume(dev, 0);
536 		retval = -EAGAIN;
537 		goto out;
538 	}
539 
540 	/* Maybe the parent is now able to suspend. */
541 	if (parent && !parent->power.ignore_children && !dev->power.irq_safe) {
542 		spin_unlock(&dev->power.lock);
543 
544 		spin_lock(&parent->power.lock);
545 		rpm_idle(parent, RPM_ASYNC);
546 		spin_unlock(&parent->power.lock);
547 
548 		spin_lock(&dev->power.lock);
549 	}
550 
551  out:
552 	trace_rpm_return_int_rcuidle(dev, _THIS_IP_, retval);
553 
554 	return retval;
555 
556  fail:
557 	dev_pm_disable_wake_irq_check(dev);
558 	__update_runtime_status(dev, RPM_ACTIVE);
559 	dev->power.deferred_resume = false;
560 	wake_up_all(&dev->power.wait_queue);
561 
562 	if (retval == -EAGAIN || retval == -EBUSY) {
563 		dev->power.runtime_error = 0;
564 
565 		/*
566 		 * If the callback routine failed an autosuspend, and
567 		 * if the last_busy time has been updated so that there
568 		 * is a new autosuspend expiration time, automatically
569 		 * reschedule another autosuspend.
570 		 */
571 		if ((rpmflags & RPM_AUTO) &&
572 		    pm_runtime_autosuspend_expiration(dev) != 0)
573 			goto repeat;
574 	} else {
575 		pm_runtime_cancel_pending(dev);
576 	}
577 	goto out;
578 }
579 
580 /**
581  * rpm_resume - Carry out runtime resume of given device.
582  * @dev: Device to resume.
583  * @rpmflags: Flag bits.
584  *
585  * Check if the device's runtime PM status allows it to be resumed.  Cancel
586  * any scheduled or pending requests.  If another resume has been started
587  * earlier, either return immediately or wait for it to finish, depending on the
588  * RPM_NOWAIT and RPM_ASYNC flags.  Similarly, if there's a suspend running in
589  * parallel with this function, either tell the other process to resume after
590  * suspending (deferred_resume) or wait for it to finish.  If the RPM_ASYNC
591  * flag is set then queue a resume request; otherwise run the
592  * ->runtime_resume() callback directly.  Queue an idle notification for the
593  * device if the resume succeeded.
594  *
595  * This function must be called under dev->power.lock with interrupts disabled.
596  */
rpm_resume(struct device * dev,int rpmflags)597 static int rpm_resume(struct device *dev, int rpmflags)
598 	__releases(&dev->power.lock) __acquires(&dev->power.lock)
599 {
600 	int (*callback)(struct device *);
601 	struct device *parent = NULL;
602 	int retval = 0;
603 
604 	trace_rpm_resume_rcuidle(dev, rpmflags);
605 
606  repeat:
607 	if (dev->power.runtime_error)
608 		retval = -EINVAL;
609 	else if (dev->power.disable_depth == 1 && dev->power.is_suspended
610 	    && dev->power.runtime_status == RPM_ACTIVE)
611 		retval = 1;
612 	else if (dev->power.disable_depth > 0)
613 		retval = -EACCES;
614 	if (retval)
615 		goto out;
616 
617 	/*
618 	 * Other scheduled or pending requests need to be canceled.  Small
619 	 * optimization: If an autosuspend timer is running, leave it running
620 	 * rather than cancelling it now only to restart it again in the near
621 	 * future.
622 	 */
623 	dev->power.request = RPM_REQ_NONE;
624 	if (!dev->power.timer_autosuspends)
625 		pm_runtime_deactivate_timer(dev);
626 
627 	if (dev->power.runtime_status == RPM_ACTIVE) {
628 		retval = 1;
629 		goto out;
630 	}
631 
632 	if (dev->power.runtime_status == RPM_RESUMING
633 	    || dev->power.runtime_status == RPM_SUSPENDING) {
634 		DEFINE_WAIT(wait);
635 
636 		if (rpmflags & (RPM_ASYNC | RPM_NOWAIT)) {
637 			if (dev->power.runtime_status == RPM_SUSPENDING)
638 				dev->power.deferred_resume = true;
639 			else
640 				retval = -EINPROGRESS;
641 			goto out;
642 		}
643 
644 		if (dev->power.irq_safe) {
645 			spin_unlock(&dev->power.lock);
646 
647 			cpu_relax();
648 
649 			spin_lock(&dev->power.lock);
650 			goto repeat;
651 		}
652 
653 		/* Wait for the operation carried out in parallel with us. */
654 		for (;;) {
655 			prepare_to_wait(&dev->power.wait_queue, &wait,
656 					TASK_UNINTERRUPTIBLE);
657 			if (dev->power.runtime_status != RPM_RESUMING
658 			    && dev->power.runtime_status != RPM_SUSPENDING)
659 				break;
660 
661 			spin_unlock_irq(&dev->power.lock);
662 
663 			schedule();
664 
665 			spin_lock_irq(&dev->power.lock);
666 		}
667 		finish_wait(&dev->power.wait_queue, &wait);
668 		goto repeat;
669 	}
670 
671 	/*
672 	 * See if we can skip waking up the parent.  This is safe only if
673 	 * power.no_callbacks is set, because otherwise we don't know whether
674 	 * the resume will actually succeed.
675 	 */
676 	if (dev->power.no_callbacks && !parent && dev->parent) {
677 		spin_lock_nested(&dev->parent->power.lock, SINGLE_DEPTH_NESTING);
678 		if (dev->parent->power.disable_depth > 0
679 		    || dev->parent->power.ignore_children
680 		    || dev->parent->power.runtime_status == RPM_ACTIVE) {
681 			atomic_inc(&dev->parent->power.child_count);
682 			spin_unlock(&dev->parent->power.lock);
683 			retval = 1;
684 			goto no_callback;	/* Assume success. */
685 		}
686 		spin_unlock(&dev->parent->power.lock);
687 	}
688 
689 	/* Carry out an asynchronous or a synchronous resume. */
690 	if (rpmflags & RPM_ASYNC) {
691 		dev->power.request = RPM_REQ_RESUME;
692 		if (!dev->power.request_pending) {
693 			dev->power.request_pending = true;
694 			queue_work(pm_wq, &dev->power.work);
695 		}
696 		retval = 0;
697 		goto out;
698 	}
699 
700 	if (!parent && dev->parent) {
701 		/*
702 		 * Increment the parent's usage counter and resume it if
703 		 * necessary.  Not needed if dev is irq-safe; then the
704 		 * parent is permanently resumed.
705 		 */
706 		parent = dev->parent;
707 		if (dev->power.irq_safe)
708 			goto skip_parent;
709 		spin_unlock(&dev->power.lock);
710 
711 		pm_runtime_get_noresume(parent);
712 
713 		spin_lock(&parent->power.lock);
714 		/*
715 		 * We can resume if the parent's runtime PM is disabled or it
716 		 * is set to ignore children.
717 		 */
718 		if (!parent->power.disable_depth
719 		    && !parent->power.ignore_children) {
720 			rpm_resume(parent, 0);
721 			if (parent->power.runtime_status != RPM_ACTIVE)
722 				retval = -EBUSY;
723 		}
724 		spin_unlock(&parent->power.lock);
725 
726 		spin_lock(&dev->power.lock);
727 		if (retval)
728 			goto out;
729 		goto repeat;
730 	}
731  skip_parent:
732 
733 	if (dev->power.no_callbacks)
734 		goto no_callback;	/* Assume success. */
735 
736 	__update_runtime_status(dev, RPM_RESUMING);
737 
738 	callback = RPM_GET_CALLBACK(dev, runtime_resume);
739 
740 	dev_pm_disable_wake_irq_check(dev);
741 	retval = rpm_callback(callback, dev);
742 	if (retval) {
743 		__update_runtime_status(dev, RPM_SUSPENDED);
744 		pm_runtime_cancel_pending(dev);
745 		dev_pm_enable_wake_irq_check(dev, false);
746 	} else {
747  no_callback:
748 		__update_runtime_status(dev, RPM_ACTIVE);
749 		pm_runtime_mark_last_busy(dev);
750 		if (parent)
751 			atomic_inc(&parent->power.child_count);
752 	}
753 	wake_up_all(&dev->power.wait_queue);
754 
755 	if (retval >= 0)
756 		rpm_idle(dev, RPM_ASYNC);
757 
758  out:
759 	if (parent && !dev->power.irq_safe) {
760 		spin_unlock_irq(&dev->power.lock);
761 
762 		pm_runtime_put(parent);
763 
764 		spin_lock_irq(&dev->power.lock);
765 	}
766 
767 	trace_rpm_return_int_rcuidle(dev, _THIS_IP_, retval);
768 
769 	return retval;
770 }
771 
772 /**
773  * pm_runtime_work - Universal runtime PM work function.
774  * @work: Work structure used for scheduling the execution of this function.
775  *
776  * Use @work to get the device object the work is to be done for, determine what
777  * is to be done and execute the appropriate runtime PM function.
778  */
pm_runtime_work(struct work_struct * work)779 static void pm_runtime_work(struct work_struct *work)
780 {
781 	struct device *dev = container_of(work, struct device, power.work);
782 	enum rpm_request req;
783 
784 	spin_lock_irq(&dev->power.lock);
785 
786 	if (!dev->power.request_pending)
787 		goto out;
788 
789 	req = dev->power.request;
790 	dev->power.request = RPM_REQ_NONE;
791 	dev->power.request_pending = false;
792 
793 	switch (req) {
794 	case RPM_REQ_NONE:
795 		break;
796 	case RPM_REQ_IDLE:
797 		rpm_idle(dev, RPM_NOWAIT);
798 		break;
799 	case RPM_REQ_SUSPEND:
800 		rpm_suspend(dev, RPM_NOWAIT);
801 		break;
802 	case RPM_REQ_AUTOSUSPEND:
803 		rpm_suspend(dev, RPM_NOWAIT | RPM_AUTO);
804 		break;
805 	case RPM_REQ_RESUME:
806 		rpm_resume(dev, RPM_NOWAIT);
807 		break;
808 	}
809 
810  out:
811 	spin_unlock_irq(&dev->power.lock);
812 }
813 
814 /**
815  * pm_suspend_timer_fn - Timer function for pm_schedule_suspend().
816  * @data: Device pointer passed by pm_schedule_suspend().
817  *
818  * Check if the time is right and queue a suspend request.
819  */
pm_suspend_timer_fn(unsigned long data)820 static void pm_suspend_timer_fn(unsigned long data)
821 {
822 	struct device *dev = (struct device *)data;
823 	unsigned long flags;
824 	unsigned long expires;
825 
826 	spin_lock_irqsave(&dev->power.lock, flags);
827 
828 	expires = dev->power.timer_expires;
829 	/* If 'expire' is after 'jiffies' we've been called too early. */
830 	if (expires > 0 && !time_after(expires, jiffies)) {
831 		dev->power.timer_expires = 0;
832 		rpm_suspend(dev, dev->power.timer_autosuspends ?
833 		    (RPM_ASYNC | RPM_AUTO) : RPM_ASYNC);
834 	}
835 
836 	spin_unlock_irqrestore(&dev->power.lock, flags);
837 }
838 
839 /**
840  * pm_schedule_suspend - Set up a timer to submit a suspend request in future.
841  * @dev: Device to suspend.
842  * @delay: Time to wait before submitting a suspend request, in milliseconds.
843  */
pm_schedule_suspend(struct device * dev,unsigned int delay)844 int pm_schedule_suspend(struct device *dev, unsigned int delay)
845 {
846 	unsigned long flags;
847 	int retval;
848 
849 	spin_lock_irqsave(&dev->power.lock, flags);
850 
851 	if (!delay) {
852 		retval = rpm_suspend(dev, RPM_ASYNC);
853 		goto out;
854 	}
855 
856 	retval = rpm_check_suspend_allowed(dev);
857 	if (retval)
858 		goto out;
859 
860 	/* Other scheduled or pending requests need to be canceled. */
861 	pm_runtime_cancel_pending(dev);
862 
863 	dev->power.timer_expires = jiffies + msecs_to_jiffies(delay);
864 	dev->power.timer_expires += !dev->power.timer_expires;
865 	dev->power.timer_autosuspends = 0;
866 	mod_timer(&dev->power.suspend_timer, dev->power.timer_expires);
867 
868  out:
869 	spin_unlock_irqrestore(&dev->power.lock, flags);
870 
871 	return retval;
872 }
873 EXPORT_SYMBOL_GPL(pm_schedule_suspend);
874 
875 /**
876  * __pm_runtime_idle - Entry point for runtime idle operations.
877  * @dev: Device to send idle notification for.
878  * @rpmflags: Flag bits.
879  *
880  * If the RPM_GET_PUT flag is set, decrement the device's usage count and
881  * return immediately if it is larger than zero.  Then carry out an idle
882  * notification, either synchronous or asynchronous.
883  *
884  * This routine may be called in atomic context if the RPM_ASYNC flag is set,
885  * or if pm_runtime_irq_safe() has been called.
886  */
__pm_runtime_idle(struct device * dev,int rpmflags)887 int __pm_runtime_idle(struct device *dev, int rpmflags)
888 {
889 	unsigned long flags;
890 	int retval;
891 
892 	if (rpmflags & RPM_GET_PUT) {
893 		if (!atomic_dec_and_test(&dev->power.usage_count))
894 			return 0;
895 	}
896 
897 	might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe);
898 
899 	spin_lock_irqsave(&dev->power.lock, flags);
900 	retval = rpm_idle(dev, rpmflags);
901 	spin_unlock_irqrestore(&dev->power.lock, flags);
902 
903 	return retval;
904 }
905 EXPORT_SYMBOL_GPL(__pm_runtime_idle);
906 
907 /**
908  * __pm_runtime_suspend - Entry point for runtime put/suspend operations.
909  * @dev: Device to suspend.
910  * @rpmflags: Flag bits.
911  *
912  * If the RPM_GET_PUT flag is set, decrement the device's usage count and
913  * return immediately if it is larger than zero.  Then carry out a suspend,
914  * either synchronous or asynchronous.
915  *
916  * This routine may be called in atomic context if the RPM_ASYNC flag is set,
917  * or if pm_runtime_irq_safe() has been called.
918  */
__pm_runtime_suspend(struct device * dev,int rpmflags)919 int __pm_runtime_suspend(struct device *dev, int rpmflags)
920 {
921 	unsigned long flags;
922 	int retval;
923 
924 	if (rpmflags & RPM_GET_PUT) {
925 		if (!atomic_dec_and_test(&dev->power.usage_count))
926 			return 0;
927 	}
928 
929 	might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe);
930 
931 	spin_lock_irqsave(&dev->power.lock, flags);
932 	retval = rpm_suspend(dev, rpmflags);
933 	spin_unlock_irqrestore(&dev->power.lock, flags);
934 
935 	return retval;
936 }
937 EXPORT_SYMBOL_GPL(__pm_runtime_suspend);
938 
939 /**
940  * __pm_runtime_resume - Entry point for runtime resume operations.
941  * @dev: Device to resume.
942  * @rpmflags: Flag bits.
943  *
944  * If the RPM_GET_PUT flag is set, increment the device's usage count.  Then
945  * carry out a resume, either synchronous or asynchronous.
946  *
947  * This routine may be called in atomic context if the RPM_ASYNC flag is set,
948  * or if pm_runtime_irq_safe() has been called.
949  */
__pm_runtime_resume(struct device * dev,int rpmflags)950 int __pm_runtime_resume(struct device *dev, int rpmflags)
951 {
952 	unsigned long flags;
953 	int retval;
954 
955 	might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe &&
956 			dev->power.runtime_status != RPM_ACTIVE);
957 
958 	if (rpmflags & RPM_GET_PUT)
959 		atomic_inc(&dev->power.usage_count);
960 
961 	spin_lock_irqsave(&dev->power.lock, flags);
962 	retval = rpm_resume(dev, rpmflags);
963 	spin_unlock_irqrestore(&dev->power.lock, flags);
964 
965 	return retval;
966 }
967 EXPORT_SYMBOL_GPL(__pm_runtime_resume);
968 
969 /**
970  * pm_runtime_get_if_in_use - Conditionally bump up the device's usage counter.
971  * @dev: Device to handle.
972  *
973  * Return -EINVAL if runtime PM is disabled for the device.
974  *
975  * If that's not the case and if the device's runtime PM status is RPM_ACTIVE
976  * and the runtime PM usage counter is nonzero, increment the counter and
977  * return 1.  Otherwise return 0 without changing the counter.
978  */
pm_runtime_get_if_in_use(struct device * dev)979 int pm_runtime_get_if_in_use(struct device *dev)
980 {
981 	unsigned long flags;
982 	int retval;
983 
984 	spin_lock_irqsave(&dev->power.lock, flags);
985 	retval = dev->power.disable_depth > 0 ? -EINVAL :
986 		dev->power.runtime_status == RPM_ACTIVE
987 			&& atomic_inc_not_zero(&dev->power.usage_count);
988 	spin_unlock_irqrestore(&dev->power.lock, flags);
989 	return retval;
990 }
991 EXPORT_SYMBOL_GPL(pm_runtime_get_if_in_use);
992 
993 /**
994  * __pm_runtime_set_status - Set runtime PM status of a device.
995  * @dev: Device to handle.
996  * @status: New runtime PM status of the device.
997  *
998  * If runtime PM of the device is disabled or its power.runtime_error field is
999  * different from zero, the status may be changed either to RPM_ACTIVE, or to
1000  * RPM_SUSPENDED, as long as that reflects the actual state of the device.
1001  * However, if the device has a parent and the parent is not active, and the
1002  * parent's power.ignore_children flag is unset, the device's status cannot be
1003  * set to RPM_ACTIVE, so -EBUSY is returned in that case.
1004  *
1005  * If successful, __pm_runtime_set_status() clears the power.runtime_error field
1006  * and the device parent's counter of unsuspended children is modified to
1007  * reflect the new status.  If the new status is RPM_SUSPENDED, an idle
1008  * notification request for the parent is submitted.
1009  */
__pm_runtime_set_status(struct device * dev,unsigned int status)1010 int __pm_runtime_set_status(struct device *dev, unsigned int status)
1011 {
1012 	struct device *parent = dev->parent;
1013 	unsigned long flags;
1014 	bool notify_parent = false;
1015 	int error = 0;
1016 
1017 	if (status != RPM_ACTIVE && status != RPM_SUSPENDED)
1018 		return -EINVAL;
1019 
1020 	spin_lock_irqsave(&dev->power.lock, flags);
1021 
1022 	if (!dev->power.runtime_error && !dev->power.disable_depth) {
1023 		error = -EAGAIN;
1024 		goto out;
1025 	}
1026 
1027 	if (dev->power.runtime_status == status)
1028 		goto out_set;
1029 
1030 	if (status == RPM_SUSPENDED) {
1031 		/* It always is possible to set the status to 'suspended'. */
1032 		if (parent) {
1033 			atomic_add_unless(&parent->power.child_count, -1, 0);
1034 			notify_parent = !parent->power.ignore_children;
1035 		}
1036 		goto out_set;
1037 	}
1038 
1039 	if (parent) {
1040 		spin_lock_nested(&parent->power.lock, SINGLE_DEPTH_NESTING);
1041 
1042 		/*
1043 		 * It is invalid to put an active child under a parent that is
1044 		 * not active, has runtime PM enabled and the
1045 		 * 'power.ignore_children' flag unset.
1046 		 */
1047 		if (!parent->power.disable_depth
1048 		    && !parent->power.ignore_children
1049 		    && parent->power.runtime_status != RPM_ACTIVE) {
1050 			dev_err(dev, "runtime PM trying to activate child device %s but parent (%s) is not active\n",
1051 				dev_name(dev),
1052 				dev_name(parent));
1053 			error = -EBUSY;
1054 		} else if (dev->power.runtime_status == RPM_SUSPENDED) {
1055 			atomic_inc(&parent->power.child_count);
1056 		}
1057 
1058 		spin_unlock(&parent->power.lock);
1059 
1060 		if (error)
1061 			goto out;
1062 	}
1063 
1064  out_set:
1065 	__update_runtime_status(dev, status);
1066 	dev->power.runtime_error = 0;
1067  out:
1068 	spin_unlock_irqrestore(&dev->power.lock, flags);
1069 
1070 	if (notify_parent)
1071 		pm_request_idle(parent);
1072 
1073 	return error;
1074 }
1075 EXPORT_SYMBOL_GPL(__pm_runtime_set_status);
1076 
1077 /**
1078  * __pm_runtime_barrier - Cancel pending requests and wait for completions.
1079  * @dev: Device to handle.
1080  *
1081  * Flush all pending requests for the device from pm_wq and wait for all
1082  * runtime PM operations involving the device in progress to complete.
1083  *
1084  * Should be called under dev->power.lock with interrupts disabled.
1085  */
__pm_runtime_barrier(struct device * dev)1086 static void __pm_runtime_barrier(struct device *dev)
1087 {
1088 	pm_runtime_deactivate_timer(dev);
1089 
1090 	if (dev->power.request_pending) {
1091 		dev->power.request = RPM_REQ_NONE;
1092 		spin_unlock_irq(&dev->power.lock);
1093 
1094 		cancel_work_sync(&dev->power.work);
1095 
1096 		spin_lock_irq(&dev->power.lock);
1097 		dev->power.request_pending = false;
1098 	}
1099 
1100 	if (dev->power.runtime_status == RPM_SUSPENDING
1101 	    || dev->power.runtime_status == RPM_RESUMING
1102 	    || dev->power.idle_notification) {
1103 		DEFINE_WAIT(wait);
1104 
1105 		/* Suspend, wake-up or idle notification in progress. */
1106 		for (;;) {
1107 			prepare_to_wait(&dev->power.wait_queue, &wait,
1108 					TASK_UNINTERRUPTIBLE);
1109 			if (dev->power.runtime_status != RPM_SUSPENDING
1110 			    && dev->power.runtime_status != RPM_RESUMING
1111 			    && !dev->power.idle_notification)
1112 				break;
1113 			spin_unlock_irq(&dev->power.lock);
1114 
1115 			schedule();
1116 
1117 			spin_lock_irq(&dev->power.lock);
1118 		}
1119 		finish_wait(&dev->power.wait_queue, &wait);
1120 	}
1121 }
1122 
1123 /**
1124  * pm_runtime_barrier - Flush pending requests and wait for completions.
1125  * @dev: Device to handle.
1126  *
1127  * Prevent the device from being suspended by incrementing its usage counter and
1128  * if there's a pending resume request for the device, wake the device up.
1129  * Next, make sure that all pending requests for the device have been flushed
1130  * from pm_wq and wait for all runtime PM operations involving the device in
1131  * progress to complete.
1132  *
1133  * Return value:
1134  * 1, if there was a resume request pending and the device had to be woken up,
1135  * 0, otherwise
1136  */
pm_runtime_barrier(struct device * dev)1137 int pm_runtime_barrier(struct device *dev)
1138 {
1139 	int retval = 0;
1140 
1141 	pm_runtime_get_noresume(dev);
1142 	spin_lock_irq(&dev->power.lock);
1143 
1144 	if (dev->power.request_pending
1145 	    && dev->power.request == RPM_REQ_RESUME) {
1146 		rpm_resume(dev, 0);
1147 		retval = 1;
1148 	}
1149 
1150 	__pm_runtime_barrier(dev);
1151 
1152 	spin_unlock_irq(&dev->power.lock);
1153 	pm_runtime_put_noidle(dev);
1154 
1155 	return retval;
1156 }
1157 EXPORT_SYMBOL_GPL(pm_runtime_barrier);
1158 
1159 /**
1160  * __pm_runtime_disable - Disable runtime PM of a device.
1161  * @dev: Device to handle.
1162  * @check_resume: If set, check if there's a resume request for the device.
1163  *
1164  * Increment power.disable_depth for the device and if it was zero previously,
1165  * cancel all pending runtime PM requests for the device and wait for all
1166  * operations in progress to complete.  The device can be either active or
1167  * suspended after its runtime PM has been disabled.
1168  *
1169  * If @check_resume is set and there's a resume request pending when
1170  * __pm_runtime_disable() is called and power.disable_depth is zero, the
1171  * function will wake up the device before disabling its runtime PM.
1172  */
__pm_runtime_disable(struct device * dev,bool check_resume)1173 void __pm_runtime_disable(struct device *dev, bool check_resume)
1174 {
1175 	spin_lock_irq(&dev->power.lock);
1176 
1177 	if (dev->power.disable_depth > 0) {
1178 		dev->power.disable_depth++;
1179 		goto out;
1180 	}
1181 
1182 	/*
1183 	 * Wake up the device if there's a resume request pending, because that
1184 	 * means there probably is some I/O to process and disabling runtime PM
1185 	 * shouldn't prevent the device from processing the I/O.
1186 	 */
1187 	if (check_resume && dev->power.request_pending
1188 	    && dev->power.request == RPM_REQ_RESUME) {
1189 		/*
1190 		 * Prevent suspends and idle notifications from being carried
1191 		 * out after we have woken up the device.
1192 		 */
1193 		pm_runtime_get_noresume(dev);
1194 
1195 		rpm_resume(dev, 0);
1196 
1197 		pm_runtime_put_noidle(dev);
1198 	}
1199 
1200 	if (!dev->power.disable_depth++)
1201 		__pm_runtime_barrier(dev);
1202 
1203  out:
1204 	spin_unlock_irq(&dev->power.lock);
1205 }
1206 EXPORT_SYMBOL_GPL(__pm_runtime_disable);
1207 
1208 /**
1209  * pm_runtime_enable - Enable runtime PM of a device.
1210  * @dev: Device to handle.
1211  */
pm_runtime_enable(struct device * dev)1212 void pm_runtime_enable(struct device *dev)
1213 {
1214 	unsigned long flags;
1215 
1216 	spin_lock_irqsave(&dev->power.lock, flags);
1217 
1218 	if (dev->power.disable_depth > 0)
1219 		dev->power.disable_depth--;
1220 	else
1221 		dev_warn(dev, "Unbalanced %s!\n", __func__);
1222 
1223 	spin_unlock_irqrestore(&dev->power.lock, flags);
1224 }
1225 EXPORT_SYMBOL_GPL(pm_runtime_enable);
1226 
1227 /**
1228  * pm_runtime_forbid - Block runtime PM of a device.
1229  * @dev: Device to handle.
1230  *
1231  * Increase the device's usage count and clear its power.runtime_auto flag,
1232  * so that it cannot be suspended at run time until pm_runtime_allow() is called
1233  * for it.
1234  */
pm_runtime_forbid(struct device * dev)1235 void pm_runtime_forbid(struct device *dev)
1236 {
1237 	spin_lock_irq(&dev->power.lock);
1238 	if (!dev->power.runtime_auto)
1239 		goto out;
1240 
1241 	dev->power.runtime_auto = false;
1242 	atomic_inc(&dev->power.usage_count);
1243 	rpm_resume(dev, 0);
1244 
1245  out:
1246 	spin_unlock_irq(&dev->power.lock);
1247 }
1248 EXPORT_SYMBOL_GPL(pm_runtime_forbid);
1249 
1250 /**
1251  * pm_runtime_allow - Unblock runtime PM of a device.
1252  * @dev: Device to handle.
1253  *
1254  * Decrease the device's usage count and set its power.runtime_auto flag.
1255  */
pm_runtime_allow(struct device * dev)1256 void pm_runtime_allow(struct device *dev)
1257 {
1258 	spin_lock_irq(&dev->power.lock);
1259 	if (dev->power.runtime_auto)
1260 		goto out;
1261 
1262 	dev->power.runtime_auto = true;
1263 	if (atomic_dec_and_test(&dev->power.usage_count))
1264 		rpm_idle(dev, RPM_AUTO | RPM_ASYNC);
1265 
1266  out:
1267 	spin_unlock_irq(&dev->power.lock);
1268 }
1269 EXPORT_SYMBOL_GPL(pm_runtime_allow);
1270 
1271 /**
1272  * pm_runtime_no_callbacks - Ignore runtime PM callbacks for a device.
1273  * @dev: Device to handle.
1274  *
1275  * Set the power.no_callbacks flag, which tells the PM core that this
1276  * device is power-managed through its parent and has no runtime PM
1277  * callbacks of its own.  The runtime sysfs attributes will be removed.
1278  */
pm_runtime_no_callbacks(struct device * dev)1279 void pm_runtime_no_callbacks(struct device *dev)
1280 {
1281 	spin_lock_irq(&dev->power.lock);
1282 	dev->power.no_callbacks = 1;
1283 	spin_unlock_irq(&dev->power.lock);
1284 	if (device_is_registered(dev))
1285 		rpm_sysfs_remove(dev);
1286 }
1287 EXPORT_SYMBOL_GPL(pm_runtime_no_callbacks);
1288 
1289 /**
1290  * pm_runtime_irq_safe - Leave interrupts disabled during callbacks.
1291  * @dev: Device to handle
1292  *
1293  * Set the power.irq_safe flag, which tells the PM core that the
1294  * ->runtime_suspend() and ->runtime_resume() callbacks for this device should
1295  * always be invoked with the spinlock held and interrupts disabled.  It also
1296  * causes the parent's usage counter to be permanently incremented, preventing
1297  * the parent from runtime suspending -- otherwise an irq-safe child might have
1298  * to wait for a non-irq-safe parent.
1299  */
pm_runtime_irq_safe(struct device * dev)1300 void pm_runtime_irq_safe(struct device *dev)
1301 {
1302 	if (dev->parent)
1303 		pm_runtime_get_sync(dev->parent);
1304 	spin_lock_irq(&dev->power.lock);
1305 	dev->power.irq_safe = 1;
1306 	spin_unlock_irq(&dev->power.lock);
1307 }
1308 EXPORT_SYMBOL_GPL(pm_runtime_irq_safe);
1309 
1310 /**
1311  * update_autosuspend - Handle a change to a device's autosuspend settings.
1312  * @dev: Device to handle.
1313  * @old_delay: The former autosuspend_delay value.
1314  * @old_use: The former use_autosuspend value.
1315  *
1316  * Prevent runtime suspend if the new delay is negative and use_autosuspend is
1317  * set; otherwise allow it.  Send an idle notification if suspends are allowed.
1318  *
1319  * This function must be called under dev->power.lock with interrupts disabled.
1320  */
update_autosuspend(struct device * dev,int old_delay,int old_use)1321 static void update_autosuspend(struct device *dev, int old_delay, int old_use)
1322 {
1323 	int delay = dev->power.autosuspend_delay;
1324 
1325 	/* Should runtime suspend be prevented now? */
1326 	if (dev->power.use_autosuspend && delay < 0) {
1327 
1328 		/* If it used to be allowed then prevent it. */
1329 		if (!old_use || old_delay >= 0) {
1330 			atomic_inc(&dev->power.usage_count);
1331 			rpm_resume(dev, 0);
1332 		}
1333 	}
1334 
1335 	/* Runtime suspend should be allowed now. */
1336 	else {
1337 
1338 		/* If it used to be prevented then allow it. */
1339 		if (old_use && old_delay < 0)
1340 			atomic_dec(&dev->power.usage_count);
1341 
1342 		/* Maybe we can autosuspend now. */
1343 		rpm_idle(dev, RPM_AUTO);
1344 	}
1345 }
1346 
1347 /**
1348  * pm_runtime_set_autosuspend_delay - Set a device's autosuspend_delay value.
1349  * @dev: Device to handle.
1350  * @delay: Value of the new delay in milliseconds.
1351  *
1352  * Set the device's power.autosuspend_delay value.  If it changes to negative
1353  * and the power.use_autosuspend flag is set, prevent runtime suspends.  If it
1354  * changes the other way, allow runtime suspends.
1355  */
pm_runtime_set_autosuspend_delay(struct device * dev,int delay)1356 void pm_runtime_set_autosuspend_delay(struct device *dev, int delay)
1357 {
1358 	int old_delay, old_use;
1359 
1360 	spin_lock_irq(&dev->power.lock);
1361 	old_delay = dev->power.autosuspend_delay;
1362 	old_use = dev->power.use_autosuspend;
1363 	dev->power.autosuspend_delay = delay;
1364 	update_autosuspend(dev, old_delay, old_use);
1365 	spin_unlock_irq(&dev->power.lock);
1366 }
1367 EXPORT_SYMBOL_GPL(pm_runtime_set_autosuspend_delay);
1368 
1369 /**
1370  * __pm_runtime_use_autosuspend - Set a device's use_autosuspend flag.
1371  * @dev: Device to handle.
1372  * @use: New value for use_autosuspend.
1373  *
1374  * Set the device's power.use_autosuspend flag, and allow or prevent runtime
1375  * suspends as needed.
1376  */
__pm_runtime_use_autosuspend(struct device * dev,bool use)1377 void __pm_runtime_use_autosuspend(struct device *dev, bool use)
1378 {
1379 	int old_delay, old_use;
1380 
1381 	spin_lock_irq(&dev->power.lock);
1382 	old_delay = dev->power.autosuspend_delay;
1383 	old_use = dev->power.use_autosuspend;
1384 	dev->power.use_autosuspend = use;
1385 	update_autosuspend(dev, old_delay, old_use);
1386 	spin_unlock_irq(&dev->power.lock);
1387 }
1388 EXPORT_SYMBOL_GPL(__pm_runtime_use_autosuspend);
1389 
1390 /**
1391  * pm_runtime_init - Initialize runtime PM fields in given device object.
1392  * @dev: Device object to initialize.
1393  */
pm_runtime_init(struct device * dev)1394 void pm_runtime_init(struct device *dev)
1395 {
1396 	dev->power.runtime_status = RPM_SUSPENDED;
1397 	dev->power.idle_notification = false;
1398 
1399 	dev->power.disable_depth = 1;
1400 	atomic_set(&dev->power.usage_count, 0);
1401 
1402 	dev->power.runtime_error = 0;
1403 
1404 	atomic_set(&dev->power.child_count, 0);
1405 	pm_suspend_ignore_children(dev, false);
1406 	dev->power.runtime_auto = true;
1407 
1408 	dev->power.request_pending = false;
1409 	dev->power.request = RPM_REQ_NONE;
1410 	dev->power.deferred_resume = false;
1411 	dev->power.accounting_timestamp = jiffies;
1412 	INIT_WORK(&dev->power.work, pm_runtime_work);
1413 
1414 	dev->power.timer_expires = 0;
1415 	setup_timer(&dev->power.suspend_timer, pm_suspend_timer_fn,
1416 			(unsigned long)dev);
1417 
1418 	init_waitqueue_head(&dev->power.wait_queue);
1419 }
1420 
1421 /**
1422  * pm_runtime_reinit - Re-initialize runtime PM fields in given device object.
1423  * @dev: Device object to re-initialize.
1424  */
pm_runtime_reinit(struct device * dev)1425 void pm_runtime_reinit(struct device *dev)
1426 {
1427 	if (!pm_runtime_enabled(dev)) {
1428 		if (dev->power.runtime_status == RPM_ACTIVE)
1429 			pm_runtime_set_suspended(dev);
1430 		if (dev->power.irq_safe) {
1431 			spin_lock_irq(&dev->power.lock);
1432 			dev->power.irq_safe = 0;
1433 			spin_unlock_irq(&dev->power.lock);
1434 			if (dev->parent)
1435 				pm_runtime_put(dev->parent);
1436 		}
1437 	}
1438 }
1439 
1440 /**
1441  * pm_runtime_remove - Prepare for removing a device from device hierarchy.
1442  * @dev: Device object being removed from device hierarchy.
1443  */
pm_runtime_remove(struct device * dev)1444 void pm_runtime_remove(struct device *dev)
1445 {
1446 	__pm_runtime_disable(dev, false);
1447 	pm_runtime_reinit(dev);
1448 }
1449 
1450 /**
1451  * pm_runtime_force_suspend - Force a device into suspend state if needed.
1452  * @dev: Device to suspend.
1453  *
1454  * Disable runtime PM so we safely can check the device's runtime PM status and
1455  * if it is active, invoke it's .runtime_suspend callback to bring it into
1456  * suspend state. Keep runtime PM disabled to preserve the state unless we
1457  * encounter errors.
1458  *
1459  * Typically this function may be invoked from a system suspend callback to make
1460  * sure the device is put into low power state.
1461  */
pm_runtime_force_suspend(struct device * dev)1462 int pm_runtime_force_suspend(struct device *dev)
1463 {
1464 	int (*callback)(struct device *);
1465 	int ret = 0;
1466 
1467 	pm_runtime_disable(dev);
1468 	if (pm_runtime_status_suspended(dev))
1469 		return 0;
1470 
1471 	callback = RPM_GET_CALLBACK(dev, runtime_suspend);
1472 
1473 	if (!callback) {
1474 		ret = -ENOSYS;
1475 		goto err;
1476 	}
1477 
1478 	ret = callback(dev);
1479 	if (ret)
1480 		goto err;
1481 
1482 	pm_runtime_set_suspended(dev);
1483 	return 0;
1484 err:
1485 	pm_runtime_enable(dev);
1486 	return ret;
1487 }
1488 EXPORT_SYMBOL_GPL(pm_runtime_force_suspend);
1489 
1490 /**
1491  * pm_runtime_force_resume - Force a device into resume state.
1492  * @dev: Device to resume.
1493  *
1494  * Prior invoking this function we expect the user to have brought the device
1495  * into low power state by a call to pm_runtime_force_suspend(). Here we reverse
1496  * those actions and brings the device into full power. We update the runtime PM
1497  * status and re-enables runtime PM.
1498  *
1499  * Typically this function may be invoked from a system resume callback to make
1500  * sure the device is put into full power state.
1501  */
pm_runtime_force_resume(struct device * dev)1502 int pm_runtime_force_resume(struct device *dev)
1503 {
1504 	int (*callback)(struct device *);
1505 	int ret = 0;
1506 
1507 	callback = RPM_GET_CALLBACK(dev, runtime_resume);
1508 
1509 	if (!callback) {
1510 		ret = -ENOSYS;
1511 		goto out;
1512 	}
1513 
1514 	if (!pm_runtime_status_suspended(dev))
1515 		goto out;
1516 
1517 	ret = pm_runtime_set_active(dev);
1518 	if (ret)
1519 		goto out;
1520 
1521 	ret = callback(dev);
1522 	if (ret) {
1523 		pm_runtime_set_suspended(dev);
1524 		goto out;
1525 	}
1526 
1527 	pm_runtime_mark_last_busy(dev);
1528 out:
1529 	pm_runtime_enable(dev);
1530 	return ret;
1531 }
1532 EXPORT_SYMBOL_GPL(pm_runtime_force_resume);
1533