1	// SPDX-License-Identifier: GPL-2.0
2	/*
3	* drivers/base/power/main.c - Where the driver meets power management.
4	*
5	* Copyright (c) 2003 Patrick Mochel
6	* Copyright (c) 2003 Open Source Development Lab
7	*
8	* The driver model core calls device_pm_add() when a device is registered.
9	* This will initialize the embedded device_pm_info object in the device
10	* and add it to the list of power-controlled devices. sysfs entries for
11	* controlling device power management will also be added.
12	*
13	* A separate list is used for keeping track of power info, because the power
14	* domain dependencies may differ from the ancestral dependencies that the
15	* subsystem list maintains.
16	*/
17
18	#define pr_fmt(fmt) "PM: " fmt
19	#define dev_fmt pr_fmt
20
21	#include <linux/device.h>
22	#include <linux/export.h>
23	#include <linux/mutex.h>
24	#include <linux/pm.h>
25	#include <linux/pm_runtime.h>
26	#include <linux/pm-trace.h>
27	#include <linux/pm_wakeirq.h>
28	#include <linux/interrupt.h>
29	#include <linux/sched.h>
30	#include <linux/sched/debug.h>
31	#include <linux/async.h>
32	#include <linux/suspend.h>
33	#include <trace/events/power.h>
34	#include <linux/cpufreq.h>
35	#include <linux/devfreq.h>
36	#include <linux/timer.h>
37	#include <linux/nmi.h>
38
39	#include "../base.h"
40	#include "power.h"
41
42	typedef int (*pm_callback_t)(struct device *);
43
44	/*
45	* The entries in the dpm_list list are in a depth first order, simply
46	* because children are guaranteed to be discovered after parents, and
47	* are inserted at the back of the list on discovery.
48	*
49	* Since device_pm_add() may be called with a device lock held,
50	* we must never try to acquire a device lock while holding
51	* dpm_list_mutex.
52	*/
53
54	LIST_HEAD(dpm_list);
55	static LIST_HEAD(dpm_prepared_list);
56	static LIST_HEAD(dpm_suspended_list);
57	static LIST_HEAD(dpm_late_early_list);
58	static LIST_HEAD(dpm_noirq_list);
59
60	static DEFINE_MUTEX(dpm_list_mtx);
61	static pm_message_t pm_transition;
62
63	static DEFINE_MUTEX(async_wip_mtx);
64	static int async_error;
65
66	/**
67	* pm_hibernate_is_recovering - if recovering from hibernate due to error.
68	*
69	* Used to query if dev_pm_ops.thaw() is called for normal hibernation case or
70	* recovering from some error.
71	*
72	* Return: true for error case, false for normal case.
73	*/
74	bool pm_hibernate_is_recovering(void)
75	{
76	return pm_transition.event == PM_EVENT_RECOVER;
77	}
78	EXPORT_SYMBOL_GPL(pm_hibernate_is_recovering);
79
80	static const char *pm_verb(int event)
81	{
82	switch (event) {
83	case PM_EVENT_SUSPEND:
84	return "suspend";
85	case PM_EVENT_RESUME:
86	return "resume";
87	case PM_EVENT_FREEZE:
88	return "freeze";
89	case PM_EVENT_QUIESCE:
90	return "quiesce";
91	case PM_EVENT_HIBERNATE:
92	return "hibernate";
93	case PM_EVENT_THAW:
94	return "thaw";
95	case PM_EVENT_RESTORE:
96	return "restore";
97	case PM_EVENT_RECOVER:
98	return "recover";
99	case PM_EVENT_POWEROFF:
100	return "poweroff";
101	default:
102	return "(unknown PM event)";
103	}
104	}
105
106	/**
107	* device_pm_sleep_init - Initialize system suspend-related device fields.
108	* @dev: Device object being initialized.
109	*/
110	void device_pm_sleep_init(struct device *dev)
111	{
112	dev->power.is_prepared = false;
113	dev->power.is_suspended = false;
114	dev->power.is_noirq_suspended = false;
115	dev->power.is_late_suspended = false;
116	init_completion(x: &dev->power.completion);
117	complete_all(&dev->power.completion);
118	dev->power.wakeup = NULL;
119	INIT_LIST_HEAD(list: &dev->power.entry);
120	}
121
122	/**
123	* device_pm_lock - Lock the list of active devices used by the PM core.
124	*/
125	void device_pm_lock(void)
126	{
127	mutex_lock(&dpm_list_mtx);
128	}
129
130	/**
131	* device_pm_unlock - Unlock the list of active devices used by the PM core.
132	*/
133	void device_pm_unlock(void)
134	{
135	mutex_unlock(lock: &dpm_list_mtx);
136	}
137
138	/**
139	* device_pm_add - Add a device to the PM core's list of active devices.
140	* @dev: Device to add to the list.
141	*/
142	void device_pm_add(struct device *dev)
143	{
144	/* Skip PM setup/initialization. */
145	if (device_pm_not_required(dev))
146	return;
147
148	pr_debug("Adding info for %s:%s\n",
149	dev->bus ? dev->bus->name : "No Bus", dev_name(dev));
150	device_pm_check_callbacks(dev);
151	mutex_lock(&dpm_list_mtx);
152	if (dev->parent && dev->parent->power.is_prepared)
153	dev_warn(dev, "parent %s should not be sleeping\n",
154	dev_name(dev->parent));
155	list_add_tail(new: &dev->power.entry, head: &dpm_list);
156	dev->power.in_dpm_list = true;
157	mutex_unlock(lock: &dpm_list_mtx);
158	}
159
160	/**
161	* device_pm_remove - Remove a device from the PM core's list of active devices.
162	* @dev: Device to be removed from the list.
163	*/
164	void device_pm_remove(struct device *dev)
165	{
166	if (device_pm_not_required(dev))
167	return;
168
169	pr_debug("Removing info for %s:%s\n",
170	dev->bus ? dev->bus->name : "No Bus", dev_name(dev));
171	complete_all(&dev->power.completion);
172	mutex_lock(&dpm_list_mtx);
173	list_del_init(entry: &dev->power.entry);
174	dev->power.in_dpm_list = false;
175	mutex_unlock(lock: &dpm_list_mtx);
176	device_wakeup_disable(dev);
177	pm_runtime_remove(dev);
178	device_pm_check_callbacks(dev);
179	}
180
181	/**
182	* device_pm_move_before - Move device in the PM core's list of active devices.
183	* @deva: Device to move in dpm_list.
184	* @devb: Device @deva should come before.
185	*/
186	void device_pm_move_before(struct device *deva, struct device *devb)
187	{
188	pr_debug("Moving %s:%s before %s:%s\n",
189	deva->bus ? deva->bus->name : "No Bus", dev_name(deva),
190	devb->bus ? devb->bus->name : "No Bus", dev_name(devb));
191	/* Delete deva from dpm_list and reinsert before devb. */
192	list_move_tail(list: &deva->power.entry, head: &devb->power.entry);
193	}
194
195	/**
196	* device_pm_move_after - Move device in the PM core's list of active devices.
197	* @deva: Device to move in dpm_list.
198	* @devb: Device @deva should come after.
199	*/
200	void device_pm_move_after(struct device *deva, struct device *devb)
201	{
202	pr_debug("Moving %s:%s after %s:%s\n",
203	deva->bus ? deva->bus->name : "No Bus", dev_name(deva),
204	devb->bus ? devb->bus->name : "No Bus", dev_name(devb));
205	/* Delete deva from dpm_list and reinsert after devb. */
206	list_move(list: &deva->power.entry, head: &devb->power.entry);
207	}
208
209	/**
210	* device_pm_move_last - Move device to end of the PM core's list of devices.
211	* @dev: Device to move in dpm_list.
212	*/
213	void device_pm_move_last(struct device *dev)
214	{
215	pr_debug("Moving %s:%s to end of list\n",
216	dev->bus ? dev->bus->name : "No Bus", dev_name(dev));
217	list_move_tail(list: &dev->power.entry, head: &dpm_list);
218	}
219
220	static ktime_t initcall_debug_start(struct device *dev, void *cb)
221	{
222	if (!pm_print_times_enabled)
223	return 0;
224
225	dev_info(dev, "calling %ps @ %i, parent: %s\n", cb,
226	task_pid_nr(current),
227	dev->parent ? dev_name(dev->parent) : "none");
228	return ktime_get();
229	}
230
231	static void initcall_debug_report(struct device *dev, ktime_t calltime,
232	void *cb, int error)
233	{
234	ktime_t rettime;
235
236	if (!pm_print_times_enabled)
237	return;
238
239	rettime = ktime_get();
240	dev_info(dev, "%ps returned %d after %Ld usecs\n", cb, error,
241	(unsigned long long)ktime_us_delta(rettime, calltime));
242	}
243
244	/**
245	* dpm_wait - Wait for a PM operation to complete.
246	* @dev: Device to wait for.
247	* @async: If unset, wait only if the device's power.async_suspend flag is set.
248	*/
249	static void dpm_wait(struct device *dev, bool async)
250	{
251	if (!dev)
252	return;
253
254	if (async || (pm_async_enabled && dev->power.async_suspend))
255	wait_for_completion(&dev->power.completion);
256	}
257
258	static int dpm_wait_fn(struct device *dev, void *async_ptr)
259	{
260	dpm_wait(dev, async: *((bool *)async_ptr));
261	return 0;
262	}
263
264	static void dpm_wait_for_children(struct device *dev, bool async)
265	{
266	device_for_each_child(parent: dev, data: &async, fn: dpm_wait_fn);
267	}
268
269	static void dpm_wait_for_suppliers(struct device *dev, bool async)
270	{
271	struct device_link *link;
272	int idx;
273
274	idx = device_links_read_lock();
275
276	/*
277	* If the supplier goes away right after we've checked the link to it,
278	* we'll wait for its completion to change the state, but that's fine,
279	* because the only things that will block as a result are the SRCU
280	* callbacks freeing the link objects for the links in the list we're
281	* walking.
282	*/
283	dev_for_each_link_to_supplier(link, dev)
284	if (READ_ONCE(link->status) != DL_STATE_DORMANT &&
285	!device_link_flag_is_sync_state_only(flags: link->flags))
286	dpm_wait(dev: link->supplier, async);
287
288	device_links_read_unlock(idx);
289	}
290
291	static bool dpm_wait_for_superior(struct device *dev, bool async)
292	{
293	struct device *parent;
294
295	/*
296	* If the device is resumed asynchronously and the parent's callback
297	* deletes both the device and the parent itself, the parent object may
298	* be freed while this function is running, so avoid that by reference
299	* counting the parent once more unless the device has been deleted
300	* already (in which case return right away).
301	*/
302	mutex_lock(&dpm_list_mtx);
303
304	if (!device_pm_initialized(dev)) {
305	mutex_unlock(lock: &dpm_list_mtx);
306	return false;
307	}
308
309	parent = get_device(dev: dev->parent);
310
311	mutex_unlock(lock: &dpm_list_mtx);
312
313	dpm_wait(dev: parent, async);
314	put_device(dev: parent);
315
316	dpm_wait_for_suppliers(dev, async);
317
318	/*
319	* If the parent's callback has deleted the device, attempting to resume
320	* it would be invalid, so avoid doing that then.
321	*/
322	return device_pm_initialized(dev);
323	}
324
325	static void dpm_wait_for_consumers(struct device *dev, bool async)
326	{
327	struct device_link *link;
328	int idx;
329
330	idx = device_links_read_lock();
331
332	/*
333	* The status of a device link can only be changed from "dormant" by a
334	* probe, but that cannot happen during system suspend/resume. In
335	* theory it can change to "dormant" at that time, but then it is
336	* reasonable to wait for the target device anyway (eg. if it goes
337	* away, it's better to wait for it to go away completely and then
338	* continue instead of trying to continue in parallel with its
339	* unregistration).
340	*/
341	dev_for_each_link_to_consumer(link, dev)
342	if (READ_ONCE(link->status) != DL_STATE_DORMANT &&
343	!device_link_flag_is_sync_state_only(flags: link->flags))
344	dpm_wait(dev: link->consumer, async);
345
346	device_links_read_unlock(idx);
347	}
348
349	static void dpm_wait_for_subordinate(struct device *dev, bool async)
350	{
351	dpm_wait_for_children(dev, async);
352	dpm_wait_for_consumers(dev, async);
353	}
354
355	/**
356	* pm_op - Return the PM operation appropriate for given PM event.
357	* @ops: PM operations to choose from.
358	* @state: PM transition of the system being carried out.
359	*/
360	static pm_callback_t pm_op(const struct dev_pm_ops *ops, pm_message_t state)
361	{
362	switch (state.event) {
363	#ifdef CONFIG_SUSPEND
364	case PM_EVENT_SUSPEND:
365	return ops->suspend;
366	case PM_EVENT_RESUME:
367	return ops->resume;
368	#endif /* CONFIG_SUSPEND */
369	#ifdef CONFIG_HIBERNATE_CALLBACKS
370	case PM_EVENT_FREEZE:
371	case PM_EVENT_QUIESCE:
372	return ops->freeze;
373	case PM_EVENT_POWEROFF:
374	case PM_EVENT_HIBERNATE:
375	return ops->poweroff;
376	case PM_EVENT_THAW:
377	case PM_EVENT_RECOVER:
378	return ops->thaw;
379	case PM_EVENT_RESTORE:
380	return ops->restore;
381	#endif /* CONFIG_HIBERNATE_CALLBACKS */
382	}
383
384	return NULL;
385	}
386
387	/**
388	* pm_late_early_op - Return the PM operation appropriate for given PM event.
389	* @ops: PM operations to choose from.
390	* @state: PM transition of the system being carried out.
391	*
392	* Runtime PM is disabled for @dev while this function is being executed.
393	*/
394	static pm_callback_t pm_late_early_op(const struct dev_pm_ops *ops,
395	pm_message_t state)
396	{
397	switch (state.event) {
398	#ifdef CONFIG_SUSPEND
399	case PM_EVENT_SUSPEND:
400	return ops->suspend_late;
401	case PM_EVENT_RESUME:
402	return ops->resume_early;
403	#endif /* CONFIG_SUSPEND */
404	#ifdef CONFIG_HIBERNATE_CALLBACKS
405	case PM_EVENT_FREEZE:
406	case PM_EVENT_QUIESCE:
407	return ops->freeze_late;
408	case PM_EVENT_POWEROFF:
409	case PM_EVENT_HIBERNATE:
410	return ops->poweroff_late;
411	case PM_EVENT_THAW:
412	case PM_EVENT_RECOVER:
413	return ops->thaw_early;
414	case PM_EVENT_RESTORE:
415	return ops->restore_early;
416	#endif /* CONFIG_HIBERNATE_CALLBACKS */
417	}
418
419	return NULL;
420	}
421
422	/**
423	* pm_noirq_op - Return the PM operation appropriate for given PM event.
424	* @ops: PM operations to choose from.
425	* @state: PM transition of the system being carried out.
426	*
427	* The driver of @dev will not receive interrupts while this function is being
428	* executed.
429	*/
430	static pm_callback_t pm_noirq_op(const struct dev_pm_ops *ops, pm_message_t state)
431	{
432	switch (state.event) {
433	#ifdef CONFIG_SUSPEND
434	case PM_EVENT_SUSPEND:
435	return ops->suspend_noirq;
436	case PM_EVENT_RESUME:
437	return ops->resume_noirq;
438	#endif /* CONFIG_SUSPEND */
439	#ifdef CONFIG_HIBERNATE_CALLBACKS
440	case PM_EVENT_FREEZE:
441	case PM_EVENT_QUIESCE:
442	return ops->freeze_noirq;
443	case PM_EVENT_POWEROFF:
444	case PM_EVENT_HIBERNATE:
445	return ops->poweroff_noirq;
446	case PM_EVENT_THAW:
447	case PM_EVENT_RECOVER:
448	return ops->thaw_noirq;
449	case PM_EVENT_RESTORE:
450	return ops->restore_noirq;
451	#endif /* CONFIG_HIBERNATE_CALLBACKS */
452	}
453
454	return NULL;
455	}
456
457	static void pm_dev_dbg(struct device *dev, pm_message_t state, const char *info)
458	{
459	dev_dbg(dev, "%s%s%s driver flags: %x\n", info, pm_verb(state.event),
460	((state.event & PM_EVENT_SLEEP) && device_may_wakeup(dev)) ?
461	", may wakeup" : "", dev->power.driver_flags);
462	}
463
464	static void pm_dev_err(struct device *dev, pm_message_t state, const char *info,
465	int error)
466	{
467	dev_err(dev, "failed to %s%s: error %d\n", pm_verb(state.event), info,
468	error);
469	}
470
471	static void dpm_show_time(ktime_t starttime, pm_message_t state, int error,
472	const char *info)
473	{
474	ktime_t calltime;
475	u64 usecs64;
476	int usecs;
477
478	calltime = ktime_get();
479	usecs64 = ktime_to_ns(ktime_sub(calltime, starttime));
480	do_div(usecs64, NSEC_PER_USEC);
481	usecs = usecs64;
482	if (usecs == 0)
483	usecs = 1;
484
485	pm_pr_dbg("%s%s%s of devices %s after %ld.%03ld msecs\n",
486	info ?: "", info ? " " : "", pm_verb(state.event),
487	error ? "aborted" : "complete",
488	usecs / USEC_PER_MSEC, usecs % USEC_PER_MSEC);
489	}
490
491	static int dpm_run_callback(pm_callback_t cb, struct device *dev,
492	pm_message_t state, const char *info)
493	{
494	ktime_t calltime;
495	int error;
496
497	if (!cb)
498	return 0;
499
500	calltime = initcall_debug_start(dev, cb);
501
502	pm_dev_dbg(dev, state, info);
503	trace_device_pm_callback_start(dev, pm_ops: info, event: state.event);
504	error = cb(dev);
505	trace_device_pm_callback_end(dev, error);
506	suspend_report_result(dev, cb, error);
507
508	initcall_debug_report(dev, calltime, cb, error);
509
510	return error;
511	}
512
513	#ifdef CONFIG_DPM_WATCHDOG
514	struct dpm_watchdog {
515	struct device *dev;
516	struct task_struct *tsk;
517	struct timer_list timer;
518	bool fatal;
519	};
520
521	#define DECLARE_DPM_WATCHDOG_ON_STACK(wd) \
522	struct dpm_watchdog wd
523
524	static bool __read_mostly dpm_watchdog_all_cpu_backtrace;
525	module_param(dpm_watchdog_all_cpu_backtrace, bool, 0644);
526	MODULE_PARM_DESC(dpm_watchdog_all_cpu_backtrace,
527	"Backtrace all CPUs on DPM watchdog timeout");
528
529	/**
530	* dpm_watchdog_handler - Driver suspend / resume watchdog handler.
531	* @t: The timer that PM watchdog depends on.
532	*
533	* Called when a driver has timed out suspending or resuming.
534	* There's not much we can do here to recover so panic() to
535	* capture a crash-dump in pstore.
536	*/
537	static void dpm_watchdog_handler(struct timer_list *t)
538	{
539	struct dpm_watchdog *wd = timer_container_of(wd, t, timer);
540	struct timer_list *timer = &wd->timer;
541	unsigned int time_left;
542
543	if (wd->fatal) {
544	unsigned int this_cpu = smp_processor_id();
545
546	dev_emerg(wd->dev, "**** DPM device timeout ****\n");
547	show_stack(task: wd->tsk, NULL, KERN_EMERG);
548	if (dpm_watchdog_all_cpu_backtrace)
549	trigger_allbutcpu_cpu_backtrace(exclude_cpu: this_cpu);
550	panic(fmt: "%s %s: unrecoverable failure\n",
551	dev_driver_string(dev: wd->dev), dev_name(dev: wd->dev));
552	}
553
554	time_left = CONFIG_DPM_WATCHDOG_TIMEOUT - CONFIG_DPM_WATCHDOG_WARNING_TIMEOUT;
555	dev_warn(wd->dev, "**** DPM device timeout after %u seconds; %u seconds until panic ****\n",
556	CONFIG_DPM_WATCHDOG_WARNING_TIMEOUT, time_left);
557	show_stack(task: wd->tsk, NULL, KERN_WARNING);
558
559	wd->fatal = true;
560	mod_timer(timer, expires: jiffies + HZ * time_left);
561	}
562
563	/**
564	* dpm_watchdog_set - Enable pm watchdog for given device.
565	* @wd: Watchdog. Must be allocated on the stack.
566	* @dev: Device to handle.
567	*/
568	static void dpm_watchdog_set(struct dpm_watchdog *wd, struct device *dev)
569	{
570	struct timer_list *timer = &wd->timer;
571
572	wd->dev = dev;
573	wd->tsk = current;
574	wd->fatal = CONFIG_DPM_WATCHDOG_TIMEOUT == CONFIG_DPM_WATCHDOG_WARNING_TIMEOUT;
575
576	timer_setup_on_stack(timer, dpm_watchdog_handler, 0);
577	/* use same timeout value for both suspend and resume */
578	timer->expires = jiffies + HZ * CONFIG_DPM_WATCHDOG_WARNING_TIMEOUT;
579	add_timer(timer);
580	}
581
582	/**
583	* dpm_watchdog_clear - Disable suspend/resume watchdog.
584	* @wd: Watchdog to disable.
585	*/
586	static void dpm_watchdog_clear(struct dpm_watchdog *wd)
587	{
588	struct timer_list *timer = &wd->timer;
589
590	timer_delete_sync(timer);
591	timer_destroy_on_stack(timer);
592	}
593	#else
594	#define DECLARE_DPM_WATCHDOG_ON_STACK(wd)
595	#define dpm_watchdog_set(x, y)
596	#define dpm_watchdog_clear(x)
597	#endif
598
599	/*------------------------- Resume routines -------------------------*/
600
601	/**
602	* dev_pm_skip_resume - System-wide device resume optimization check.
603	* @dev: Target device.
604	*
605	* Return:
606	* - %false if the transition under way is RESTORE.
607	* - Return value of dev_pm_skip_suspend() if the transition under way is THAW.
608	* - The logical negation of %power.must_resume otherwise (that is, when the
609	* transition under way is RESUME).
610	*/
611	bool dev_pm_skip_resume(struct device *dev)
612	{
613	if (pm_transition.event == PM_EVENT_RESTORE)
614	return false;
615
616	if (pm_transition.event == PM_EVENT_THAW)
617	return dev_pm_skip_suspend(dev);
618
619	return !dev->power.must_resume;
620	}
621
622	static bool is_async(struct device *dev)
623	{
624	return dev->power.async_suspend && pm_async_enabled
625	&& !pm_trace_is_enabled();
626	}
627
628	static bool __dpm_async(struct device *dev, async_func_t func)
629	{
630	if (dev->power.work_in_progress)
631	return true;
632
633	if (!is_async(dev))
634	return false;
635
636	dev->power.work_in_progress = true;
637
638	get_device(dev);
639
640	if (async_schedule_dev_nocall(func, dev))
641	return true;
642
643	put_device(dev);
644
645	return false;
646	}
647
648	static bool dpm_async_fn(struct device *dev, async_func_t func)
649	{
650	guard(mutex)(T: &async_wip_mtx);
651
652	return __dpm_async(dev, func);
653	}
654
655	static int dpm_async_with_cleanup(struct device *dev, void *fn)
656	{
657	guard(mutex)(T: &async_wip_mtx);
658
659	if (!__dpm_async(dev, func: fn))
660	dev->power.work_in_progress = false;
661
662	return 0;
663	}
664
665	static void dpm_async_resume_children(struct device *dev, async_func_t func)
666	{
667	/*
668	* Prevent racing with dpm_clear_async_state() during initial list
669	* walks in dpm_noirq_resume_devices(), dpm_resume_early(), and
670	* dpm_resume().
671	*/
672	guard(mutex)(T: &dpm_list_mtx);
673
674	/*
675	* Start processing "async" children of the device unless it's been
676	* started already for them.
677	*/
678	device_for_each_child(parent: dev, data: func, fn: dpm_async_with_cleanup);
679	}
680
681	static void dpm_async_resume_subordinate(struct device *dev, async_func_t func)
682	{
683	struct device_link *link;
684	int idx;
685
686	dpm_async_resume_children(dev, func);
687
688	idx = device_links_read_lock();
689
690	/* Start processing the device's "async" consumers. */
691	dev_for_each_link_to_consumer(link, dev)
692	if (READ_ONCE(link->status) != DL_STATE_DORMANT)
693	dpm_async_with_cleanup(dev: link->consumer, fn: func);
694
695	device_links_read_unlock(idx);
696	}
697
698	static void dpm_clear_async_state(struct device *dev)
699	{
700	reinit_completion(x: &dev->power.completion);
701	dev->power.work_in_progress = false;
702	}
703
704	static bool dpm_root_device(struct device *dev)
705	{
706	lockdep_assert_held(&dpm_list_mtx);
707
708	/*
709	* Since this function is required to run under dpm_list_mtx, the
710	* list_empty() below will only return true if the device's list of
711	* consumers is actually empty before calling it.
712	*/
713	return !dev->parent && list_empty(head: &dev->links.suppliers);
714	}
715
716	static void async_resume_noirq(void *data, async_cookie_t cookie);
717
718	/**
719	* device_resume_noirq - Execute a "noirq resume" callback for given device.
720	* @dev: Device to handle.
721	* @state: PM transition of the system being carried out.
722	* @async: If true, the device is being resumed asynchronously.
723	*
724	* The driver of @dev will not receive interrupts while this function is being
725	* executed.
726	*/
727	static void device_resume_noirq(struct device *dev, pm_message_t state, bool async)
728	{
729	pm_callback_t callback = NULL;
730	const char *info = NULL;
731	bool skip_resume;
732	int error = 0;
733
734	TRACE_DEVICE(dev);
735	TRACE_RESUME(0);
736
737	if (dev->power.syscore || dev->power.direct_complete)
738	goto Out;
739
740	if (!dev->power.is_noirq_suspended) {
741	/*
742	* This means that system suspend has been aborted in the noirq
743	* phase before invoking the noirq suspend callback for the
744	* device, so if device_suspend_late() has left it in suspend,
745	* device_resume_early() should leave it in suspend either in
746	* case the early resume of it depends on the noirq resume that
747	* has not run.
748	*/
749	if (dev_pm_skip_suspend(dev))
750	dev->power.must_resume = false;
751
752	goto Out;
753	}
754
755	if (!dpm_wait_for_superior(dev, async))
756	goto Out;
757
758	skip_resume = dev_pm_skip_resume(dev);
759	/*
760	* If the driver callback is skipped below or by the middle layer
761	* callback and device_resume_early() also skips the driver callback for
762	* this device later, it needs to appear as "suspended" to PM-runtime,
763	* so change its status accordingly.
764	*
765	* Otherwise, the device is going to be resumed, so set its PM-runtime
766	* status to "active" unless its power.smart_suspend flag is clear, in
767	* which case it is not necessary to update its PM-runtime status.
768	*/
769	if (skip_resume)
770	pm_runtime_set_suspended(dev);
771	else if (dev_pm_smart_suspend(dev))
772	pm_runtime_set_active(dev);
773
774	if (dev->pm_domain) {
775	info = "noirq power domain ";
776	callback = pm_noirq_op(ops: &dev->pm_domain->ops, state);
777	} else if (dev->type && dev->type->pm) {
778	info = "noirq type ";
779	callback = pm_noirq_op(ops: dev->type->pm, state);
780	} else if (dev->class && dev->class->pm) {
781	info = "noirq class ";
782	callback = pm_noirq_op(ops: dev->class->pm, state);
783	} else if (dev->bus && dev->bus->pm) {
784	info = "noirq bus ";
785	callback = pm_noirq_op(ops: dev->bus->pm, state);
786	}
787	if (callback)
788	goto Run;
789
790	if (skip_resume)
791	goto Skip;
792
793	if (dev->driver && dev->driver->pm) {
794	info = "noirq driver ";
795	callback = pm_noirq_op(ops: dev->driver->pm, state);
796	}
797
798	Run:
799	error = dpm_run_callback(cb: callback, dev, state, info);
800
801	Skip:
802	dev->power.is_noirq_suspended = false;
803
804	Out:
805	complete_all(&dev->power.completion);
806	TRACE_RESUME(error);
807
808	if (error) {
809	WRITE_ONCE(async_error, error);
810	dpm_save_failed_dev(name: dev_name(dev));
811	pm_dev_err(dev, state, info: async ? " async noirq" : " noirq", error);
812	}
813
814	dpm_async_resume_subordinate(dev, func: async_resume_noirq);
815	}
816
817	static void async_resume_noirq(void *data, async_cookie_t cookie)
818	{
819	struct device *dev = data;
820
821	device_resume_noirq(dev, state: pm_transition, async: true);
822	put_device(dev);
823	}
824
825	static void dpm_noirq_resume_devices(pm_message_t state)
826	{
827	struct device *dev;
828	ktime_t starttime = ktime_get();
829
830	trace_suspend_resume(TPS("dpm_resume_noirq"), val: state.event, start: true);
831
832	async_error = 0;
833	pm_transition = state;
834
835	mutex_lock(&dpm_list_mtx);
836
837	/*
838	* Start processing "async" root devices upfront so they don't wait for
839	* the "sync" devices they don't depend on.
840	*/
841	list_for_each_entry(dev, &dpm_noirq_list, power.entry) {
842	dpm_clear_async_state(dev);
843	if (dpm_root_device(dev))
844	dpm_async_with_cleanup(dev, fn: async_resume_noirq);
845	}
846
847	while (!list_empty(head: &dpm_noirq_list)) {
848	dev = to_device(entry: dpm_noirq_list.next);
849	list_move_tail(list: &dev->power.entry, head: &dpm_late_early_list);
850
851	if (!dpm_async_fn(dev, func: async_resume_noirq)) {
852	get_device(dev);
853
854	mutex_unlock(lock: &dpm_list_mtx);
855
856	device_resume_noirq(dev, state, async: false);
857
858	put_device(dev);
859
860	mutex_lock(&dpm_list_mtx);
861	}
862	}
863	mutex_unlock(lock: &dpm_list_mtx);
864	async_synchronize_full();
865	dpm_show_time(starttime, state, error: 0, info: "noirq");
866	if (READ_ONCE(async_error))
867	dpm_save_failed_step(step: SUSPEND_RESUME_NOIRQ);
868
869	trace_suspend_resume(TPS("dpm_resume_noirq"), val: state.event, start: false);
870	}
871
872	/**
873	* dpm_resume_noirq - Execute "noirq resume" callbacks for all devices.
874	* @state: PM transition of the system being carried out.
875	*
876	* Invoke the "noirq" resume callbacks for all devices in dpm_noirq_list and
877	* allow device drivers' interrupt handlers to be called.
878	*/
879	void dpm_resume_noirq(pm_message_t state)
880	{
881	dpm_noirq_resume_devices(state);
882
883	resume_device_irqs();
884	device_wakeup_disarm_wake_irqs();
885	}
886
887	static void async_resume_early(void *data, async_cookie_t cookie);
888
889	/**
890	* device_resume_early - Execute an "early resume" callback for given device.
891	* @dev: Device to handle.
892	* @state: PM transition of the system being carried out.
893	* @async: If true, the device is being resumed asynchronously.
894	*
895	* Runtime PM is disabled for @dev while this function is being executed.
896	*/
897	static void device_resume_early(struct device *dev, pm_message_t state, bool async)
898	{
899	pm_callback_t callback = NULL;
900	const char *info = NULL;
901	int error = 0;
902
903	TRACE_DEVICE(dev);
904	TRACE_RESUME(0);
905
906	if (dev->power.direct_complete)
907	goto Out;
908
909	if (!dev->power.is_late_suspended)
910	goto Out;
911
912	if (dev->power.syscore)
913	goto Skip;
914
915	if (!dpm_wait_for_superior(dev, async))
916	goto Out;
917
918	if (dev->pm_domain) {
919	info = "early power domain ";
920	callback = pm_late_early_op(ops: &dev->pm_domain->ops, state);
921	} else if (dev->type && dev->type->pm) {
922	info = "early type ";
923	callback = pm_late_early_op(ops: dev->type->pm, state);
924	} else if (dev->class && dev->class->pm) {
925	info = "early class ";
926	callback = pm_late_early_op(ops: dev->class->pm, state);
927	} else if (dev->bus && dev->bus->pm) {
928	info = "early bus ";
929	callback = pm_late_early_op(ops: dev->bus->pm, state);
930	}
931	if (callback)
932	goto Run;
933
934	if (dev_pm_skip_resume(dev))
935	goto Skip;
936
937	if (dev->driver && dev->driver->pm) {
938	info = "early driver ";
939	callback = pm_late_early_op(ops: dev->driver->pm, state);
940	}
941
942	Run:
943	error = dpm_run_callback(cb: callback, dev, state, info);
944
945	Skip:
946	dev->power.is_late_suspended = false;
947	pm_runtime_enable(dev);
948
949	Out:
950	TRACE_RESUME(error);
951
952	complete_all(&dev->power.completion);
953
954	if (error) {
955	WRITE_ONCE(async_error, error);
956	dpm_save_failed_dev(name: dev_name(dev));
957	pm_dev_err(dev, state, info: async ? " async early" : " early", error);
958	}
959
960	dpm_async_resume_subordinate(dev, func: async_resume_early);
961	}
962
963	static void async_resume_early(void *data, async_cookie_t cookie)
964	{
965	struct device *dev = data;
966
967	device_resume_early(dev, state: pm_transition, async: true);
968	put_device(dev);
969	}
970
971	/**
972	* dpm_resume_early - Execute "early resume" callbacks for all devices.
973	* @state: PM transition of the system being carried out.
974	*/
975	void dpm_resume_early(pm_message_t state)
976	{
977	struct device *dev;
978	ktime_t starttime = ktime_get();
979
980	trace_suspend_resume(TPS("dpm_resume_early"), val: state.event, start: true);
981
982	async_error = 0;
983	pm_transition = state;
984
985	mutex_lock(&dpm_list_mtx);
986
987	/*
988	* Start processing "async" root devices upfront so they don't wait for
989	* the "sync" devices they don't depend on.
990	*/
991	list_for_each_entry(dev, &dpm_late_early_list, power.entry) {
992	dpm_clear_async_state(dev);
993	if (dpm_root_device(dev))
994	dpm_async_with_cleanup(dev, fn: async_resume_early);
995	}
996
997	while (!list_empty(head: &dpm_late_early_list)) {
998	dev = to_device(entry: dpm_late_early_list.next);
999	list_move_tail(list: &dev->power.entry, head: &dpm_suspended_list);
1000
1001	if (!dpm_async_fn(dev, func: async_resume_early)) {
1002	get_device(dev);
1003
1004	mutex_unlock(lock: &dpm_list_mtx);
1005
1006	device_resume_early(dev, state, async: false);
1007
1008	put_device(dev);
1009
1010	mutex_lock(&dpm_list_mtx);
1011	}
1012	}
1013	mutex_unlock(lock: &dpm_list_mtx);
1014	async_synchronize_full();
1015	dpm_show_time(starttime, state, error: 0, info: "early");
1016	if (READ_ONCE(async_error))
1017	dpm_save_failed_step(step: SUSPEND_RESUME_EARLY);
1018
1019	trace_suspend_resume(TPS("dpm_resume_early"), val: state.event, start: false);
1020	}
1021
1022	/**
1023	* dpm_resume_start - Execute "noirq" and "early" device callbacks.
1024	* @state: PM transition of the system being carried out.
1025	*/
1026	void dpm_resume_start(pm_message_t state)
1027	{
1028	dpm_resume_noirq(state);
1029	dpm_resume_early(state);
1030	}
1031	EXPORT_SYMBOL_GPL(dpm_resume_start);
1032
1033	static void async_resume(void *data, async_cookie_t cookie);
1034
1035	/**
1036	* device_resume - Execute "resume" callbacks for given device.
1037	* @dev: Device to handle.
1038	* @state: PM transition of the system being carried out.
1039	* @async: If true, the device is being resumed asynchronously.
1040	*/
1041	static void device_resume(struct device *dev, pm_message_t state, bool async)
1042	{
1043	pm_callback_t callback = NULL;
1044	const char *info = NULL;
1045	int error = 0;
1046	DECLARE_DPM_WATCHDOG_ON_STACK(wd);
1047
1048	TRACE_DEVICE(dev);
1049	TRACE_RESUME(0);
1050
1051	if (dev->power.syscore)
1052	goto Complete;
1053
1054	if (!dev->power.is_suspended)
1055	goto Complete;
1056
1057	dev->power.is_suspended = false;
1058
1059	if (dev->power.direct_complete) {
1060	/*
1061	* Allow new children to be added under the device after this
1062	* point if it has no PM callbacks.
1063	*/
1064	if (dev->power.no_pm_callbacks)
1065	dev->power.is_prepared = false;
1066
1067	/* Match the pm_runtime_disable() in device_suspend(). */
1068	pm_runtime_enable(dev);
1069	goto Complete;
1070	}
1071
1072	if (!dpm_wait_for_superior(dev, async))
1073	goto Complete;
1074
1075	dpm_watchdog_set(wd: &wd, dev);
1076	device_lock(dev);
1077
1078	/*
1079	* This is a fib. But we'll allow new children to be added below
1080	* a resumed device, even if the device hasn't been completed yet.
1081	*/
1082	dev->power.is_prepared = false;
1083
1084	if (dev->pm_domain) {
1085	info = "power domain ";
1086	callback = pm_op(ops: &dev->pm_domain->ops, state);
1087	goto Driver;
1088	}
1089
1090	if (dev->type && dev->type->pm) {
1091	info = "type ";
1092	callback = pm_op(ops: dev->type->pm, state);
1093	goto Driver;
1094	}
1095
1096	if (dev->class && dev->class->pm) {
1097	info = "class ";
1098	callback = pm_op(ops: dev->class->pm, state);
1099	goto Driver;
1100	}
1101
1102	if (dev->bus) {
1103	if (dev->bus->pm) {
1104	info = "bus ";
1105	callback = pm_op(ops: dev->bus->pm, state);
1106	} else if (dev->bus->resume) {
1107	info = "legacy bus ";
1108	callback = dev->bus->resume;
1109	goto End;
1110	}
1111	}
1112
1113	Driver:
1114	if (!callback && dev->driver && dev->driver->pm) {
1115	info = "driver ";
1116	callback = pm_op(ops: dev->driver->pm, state);
1117	}
1118
1119	End:
1120	error = dpm_run_callback(cb: callback, dev, state, info);
1121
1122	device_unlock(dev);
1123	dpm_watchdog_clear(wd: &wd);
1124
1125	Complete:
1126	complete_all(&dev->power.completion);
1127
1128	TRACE_RESUME(error);
1129
1130	if (error) {
1131	WRITE_ONCE(async_error, error);
1132	dpm_save_failed_dev(name: dev_name(dev));
1133	pm_dev_err(dev, state, info: async ? " async" : "", error);
1134	}
1135
1136	dpm_async_resume_subordinate(dev, func: async_resume);
1137	}
1138
1139	static void async_resume(void *data, async_cookie_t cookie)
1140	{
1141	struct device *dev = data;
1142
1143	device_resume(dev, state: pm_transition, async: true);
1144	put_device(dev);
1145	}
1146
1147	/**
1148	* dpm_resume - Execute "resume" callbacks for non-sysdev devices.
1149	* @state: PM transition of the system being carried out.
1150	*
1151	* Execute the appropriate "resume" callback for all devices whose status
1152	* indicates that they are suspended.
1153	*/
1154	void dpm_resume(pm_message_t state)
1155	{
1156	struct device *dev;
1157	ktime_t starttime = ktime_get();
1158
1159	trace_suspend_resume(TPS("dpm_resume"), val: state.event, start: true);
1160
1161	pm_transition = state;
1162	async_error = 0;
1163
1164	mutex_lock(&dpm_list_mtx);
1165
1166	/*
1167	* Start processing "async" root devices upfront so they don't wait for
1168	* the "sync" devices they don't depend on.
1169	*/
1170	list_for_each_entry(dev, &dpm_suspended_list, power.entry) {
1171	dpm_clear_async_state(dev);
1172	if (dpm_root_device(dev))
1173	dpm_async_with_cleanup(dev, fn: async_resume);
1174	}
1175
1176	while (!list_empty(head: &dpm_suspended_list)) {
1177	dev = to_device(entry: dpm_suspended_list.next);
1178	list_move_tail(list: &dev->power.entry, head: &dpm_prepared_list);
1179
1180	if (!dpm_async_fn(dev, func: async_resume)) {
1181	get_device(dev);
1182
1183	mutex_unlock(lock: &dpm_list_mtx);
1184
1185	device_resume(dev, state, async: false);
1186
1187	put_device(dev);
1188
1189	mutex_lock(&dpm_list_mtx);
1190	}
1191	}
1192	mutex_unlock(lock: &dpm_list_mtx);
1193	async_synchronize_full();
1194	dpm_show_time(starttime, state, error: 0, NULL);
1195	if (READ_ONCE(async_error))
1196	dpm_save_failed_step(step: SUSPEND_RESUME);
1197
1198	cpufreq_resume();
1199	devfreq_resume();
1200	trace_suspend_resume(TPS("dpm_resume"), val: state.event, start: false);
1201	}
1202
1203	/**
1204	* device_complete - Complete a PM transition for given device.
1205	* @dev: Device to handle.
1206	* @state: PM transition of the system being carried out.
1207	*/
1208	static void device_complete(struct device *dev, pm_message_t state)
1209	{
1210	void (*callback)(struct device *) = NULL;
1211	const char *info = NULL;
1212
1213	if (dev->power.syscore)
1214	goto out;
1215
1216	device_lock(dev);
1217
1218	if (dev->pm_domain) {
1219	info = "completing power domain ";
1220	callback = dev->pm_domain->ops.complete;
1221	} else if (dev->type && dev->type->pm) {
1222	info = "completing type ";
1223	callback = dev->type->pm->complete;
1224	} else if (dev->class && dev->class->pm) {
1225	info = "completing class ";
1226	callback = dev->class->pm->complete;
1227	} else if (dev->bus && dev->bus->pm) {
1228	info = "completing bus ";
1229	callback = dev->bus->pm->complete;
1230	}
1231
1232	if (!callback && dev->driver && dev->driver->pm) {
1233	info = "completing driver ";
1234	callback = dev->driver->pm->complete;
1235	}
1236
1237	if (callback) {
1238	pm_dev_dbg(dev, state, info);
1239	callback(dev);
1240	}
1241
1242	device_unlock(dev);
1243
1244	out:
1245	/* If enabling runtime PM for the device is blocked, unblock it. */
1246	pm_runtime_unblock(dev);
1247	pm_runtime_put(dev);
1248	}
1249
1250	/**
1251	* dpm_complete - Complete a PM transition for all non-sysdev devices.
1252	* @state: PM transition of the system being carried out.
1253	*
1254	* Execute the ->complete() callbacks for all devices whose PM status is not
1255	* DPM_ON (this allows new devices to be registered).
1256	*/
1257	void dpm_complete(pm_message_t state)
1258	{
1259	struct list_head list;
1260
1261	trace_suspend_resume(TPS("dpm_complete"), val: state.event, start: true);
1262
1263	INIT_LIST_HEAD(list: &list);
1264	mutex_lock(&dpm_list_mtx);
1265	while (!list_empty(head: &dpm_prepared_list)) {
1266	struct device *dev = to_device(entry: dpm_prepared_list.prev);
1267
1268	get_device(dev);
1269	dev->power.is_prepared = false;
1270	list_move(list: &dev->power.entry, head: &list);
1271
1272	mutex_unlock(lock: &dpm_list_mtx);
1273
1274	trace_device_pm_callback_start(dev, pm_ops: "", event: state.event);
1275	device_complete(dev, state);
1276	trace_device_pm_callback_end(dev, error: 0);
1277
1278	put_device(dev);
1279
1280	mutex_lock(&dpm_list_mtx);
1281	}
1282	list_splice(list: &list, head: &dpm_list);
1283	mutex_unlock(lock: &dpm_list_mtx);
1284
1285	/* Allow device probing and trigger re-probing of deferred devices */
1286	device_unblock_probing();
1287	trace_suspend_resume(TPS("dpm_complete"), val: state.event, start: false);
1288	}
1289
1290	/**
1291	* dpm_resume_end - Execute "resume" callbacks and complete system transition.
1292	* @state: PM transition of the system being carried out.
1293	*
1294	* Execute "resume" callbacks for all devices and complete the PM transition of
1295	* the system.
1296	*/
1297	void dpm_resume_end(pm_message_t state)
1298	{
1299	dpm_resume(state);
1300	pm_restore_gfp_mask();
1301	dpm_complete(state);
1302	}
1303	EXPORT_SYMBOL_GPL(dpm_resume_end);
1304
1305
1306	/*------------------------- Suspend routines -------------------------*/
1307
1308	static bool dpm_leaf_device(struct device *dev)
1309	{
1310	struct device *child;
1311
1312	lockdep_assert_held(&dpm_list_mtx);
1313
1314	child = device_find_any_child(parent: dev);
1315	if (child) {
1316	put_device(dev: child);
1317
1318	return false;
1319	}
1320
1321	/*
1322	* Since this function is required to run under dpm_list_mtx, the
1323	* list_empty() below will only return true if the device's list of
1324	* consumers is actually empty before calling it.
1325	*/
1326	return list_empty(head: &dev->links.consumers);
1327	}
1328
1329	static bool dpm_async_suspend_parent(struct device *dev, async_func_t func)
1330	{
1331	guard(mutex)(T: &dpm_list_mtx);
1332
1333	/*
1334	* If the device is suspended asynchronously and the parent's callback
1335	* deletes both the device and the parent itself, the parent object may
1336	* be freed while this function is running, so avoid that by checking
1337	* if the device has been deleted already as the parent cannot be
1338	* deleted before it.
1339	*/
1340	if (!device_pm_initialized(dev))
1341	return false;
1342
1343	/* Start processing the device's parent if it is "async". */
1344	if (dev->parent)
1345	dpm_async_with_cleanup(dev: dev->parent, fn: func);
1346
1347	return true;
1348	}
1349
1350	static void dpm_async_suspend_superior(struct device *dev, async_func_t func)
1351	{
1352	struct device_link *link;
1353	int idx;
1354
1355	if (!dpm_async_suspend_parent(dev, func))
1356	return;
1357
1358	idx = device_links_read_lock();
1359
1360	/* Start processing the device's "async" suppliers. */
1361	dev_for_each_link_to_supplier(link, dev)
1362	if (READ_ONCE(link->status) != DL_STATE_DORMANT)
1363	dpm_async_with_cleanup(dev: link->supplier, fn: func);
1364
1365	device_links_read_unlock(idx);
1366	}
1367
1368	static void dpm_async_suspend_complete_all(struct list_head *device_list)
1369	{
1370	struct device *dev;
1371
1372	guard(mutex)(T: &async_wip_mtx);
1373
1374	list_for_each_entry_reverse(dev, device_list, power.entry) {
1375	/*
1376	* In case the device is being waited for and async processing
1377	* has not started for it yet, let the waiters make progress.
1378	*/
1379	if (!dev->power.work_in_progress)
1380	complete_all(&dev->power.completion);
1381	}
1382	}
1383
1384	/**
1385	* resume_event - Return a "resume" message for given "suspend" sleep state.
1386	* @sleep_state: PM message representing a sleep state.
1387	*
1388	* Return a PM message representing the resume event corresponding to given
1389	* sleep state.
1390	*/
1391	static pm_message_t resume_event(pm_message_t sleep_state)
1392	{
1393	switch (sleep_state.event) {
1394	case PM_EVENT_SUSPEND:
1395	return PMSG_RESUME;
1396	case PM_EVENT_FREEZE:
1397	case PM_EVENT_QUIESCE:
1398	return PMSG_RECOVER;
1399	case PM_EVENT_HIBERNATE:
1400	return PMSG_RESTORE;
1401	}
1402	return PMSG_ON;
1403	}
1404
1405	static void dpm_superior_set_must_resume(struct device *dev)
1406	{
1407	struct device_link *link;
1408	int idx;
1409
1410	if (dev->parent)
1411	dev->parent->power.must_resume = true;
1412
1413	idx = device_links_read_lock();
1414
1415	dev_for_each_link_to_supplier(link, dev)
1416	link->supplier->power.must_resume = true;
1417
1418	device_links_read_unlock(idx);
1419	}
1420
1421	static void async_suspend_noirq(void *data, async_cookie_t cookie);
1422
1423	/**
1424	* device_suspend_noirq - Execute a "noirq suspend" callback for given device.
1425	* @dev: Device to handle.
1426	* @state: PM transition of the system being carried out.
1427	* @async: If true, the device is being suspended asynchronously.
1428	*
1429	* The driver of @dev will not receive interrupts while this function is being
1430	* executed.
1431	*/
1432	static void device_suspend_noirq(struct device *dev, pm_message_t state, bool async)
1433	{
1434	pm_callback_t callback = NULL;
1435	const char *info = NULL;
1436	int error = 0;
1437
1438	TRACE_DEVICE(dev);
1439	TRACE_SUSPEND(0);
1440
1441	dpm_wait_for_subordinate(dev, async);
1442
1443	if (READ_ONCE(async_error))
1444	goto Complete;
1445
1446	if (dev->power.syscore || dev->power.direct_complete)
1447	goto Complete;
1448
1449	if (dev->pm_domain) {
1450	info = "noirq power domain ";
1451	callback = pm_noirq_op(ops: &dev->pm_domain->ops, state);
1452	} else if (dev->type && dev->type->pm) {
1453	info = "noirq type ";
1454	callback = pm_noirq_op(ops: dev->type->pm, state);
1455	} else if (dev->class && dev->class->pm) {
1456	info = "noirq class ";
1457	callback = pm_noirq_op(ops: dev->class->pm, state);
1458	} else if (dev->bus && dev->bus->pm) {
1459	info = "noirq bus ";
1460	callback = pm_noirq_op(ops: dev->bus->pm, state);
1461	}
1462	if (callback)
1463	goto Run;
1464
1465	if (dev_pm_skip_suspend(dev))
1466	goto Skip;
1467
1468	if (dev->driver && dev->driver->pm) {
1469	info = "noirq driver ";
1470	callback = pm_noirq_op(ops: dev->driver->pm, state);
1471	}
1472
1473	Run:
1474	error = dpm_run_callback(cb: callback, dev, state, info);
1475	if (error) {
1476	WRITE_ONCE(async_error, error);
1477	dpm_save_failed_dev(name: dev_name(dev));
1478	pm_dev_err(dev, state, info: async ? " async noirq" : " noirq", error);
1479	goto Complete;
1480	}
1481
1482	Skip:
1483	dev->power.is_noirq_suspended = true;
1484
1485	/*
1486	* Devices must be resumed unless they are explicitly allowed to be left
1487	* in suspend, but even in that case skipping the resume of devices that
1488	* were in use right before the system suspend (as indicated by their
1489	* runtime PM usage counters and child counters) would be suboptimal.
1490	*/
1491	if (!(dev_pm_test_driver_flags(dev, DPM_FLAG_MAY_SKIP_RESUME) &&
1492	dev->power.may_skip_resume) || !pm_runtime_need_not_resume(dev))
1493	dev->power.must_resume = true;
1494
1495	if (dev->power.must_resume)
1496	dpm_superior_set_must_resume(dev);
1497
1498	Complete:
1499	complete_all(&dev->power.completion);
1500	TRACE_SUSPEND(error);
1501
1502	if (error || READ_ONCE(async_error))
1503	return;
1504
1505	dpm_async_suspend_superior(dev, func: async_suspend_noirq);
1506	}
1507
1508	static void async_suspend_noirq(void *data, async_cookie_t cookie)
1509	{
1510	struct device *dev = data;
1511
1512	device_suspend_noirq(dev, state: pm_transition, async: true);
1513	put_device(dev);
1514	}
1515
1516	static int dpm_noirq_suspend_devices(pm_message_t state)
1517	{
1518	ktime_t starttime = ktime_get();
1519	struct device *dev;
1520	int error;
1521
1522	trace_suspend_resume(TPS("dpm_suspend_noirq"), val: state.event, start: true);
1523
1524	pm_transition = state;
1525	async_error = 0;
1526
1527	mutex_lock(&dpm_list_mtx);
1528
1529	/*
1530	* Start processing "async" leaf devices upfront so they don't need to
1531	* wait for the "sync" devices they don't depend on.
1532	*/
1533	list_for_each_entry_reverse(dev, &dpm_late_early_list, power.entry) {
1534	dpm_clear_async_state(dev);
1535	if (dpm_leaf_device(dev))
1536	dpm_async_with_cleanup(dev, fn: async_suspend_noirq);
1537	}
1538
1539	while (!list_empty(head: &dpm_late_early_list)) {
1540	dev = to_device(entry: dpm_late_early_list.prev);
1541
1542	list_move(list: &dev->power.entry, head: &dpm_noirq_list);
1543
1544	if (dpm_async_fn(dev, func: async_suspend_noirq))
1545	continue;
1546
1547	get_device(dev);
1548
1549	mutex_unlock(lock: &dpm_list_mtx);
1550
1551	device_suspend_noirq(dev, state, async: false);
1552
1553	put_device(dev);
1554
1555	mutex_lock(&dpm_list_mtx);
1556
1557	if (READ_ONCE(async_error)) {
1558	dpm_async_suspend_complete_all(device_list: &dpm_late_early_list);
1559	/*
1560	* Move all devices to the target list to resume them
1561	* properly.
1562	*/
1563	list_splice_init(list: &dpm_late_early_list, head: &dpm_noirq_list);
1564	break;
1565	}
1566	}
1567
1568	mutex_unlock(lock: &dpm_list_mtx);
1569
1570	async_synchronize_full();
1571
1572	error = READ_ONCE(async_error);
1573	if (error)
1574	dpm_save_failed_step(step: SUSPEND_SUSPEND_NOIRQ);
1575
1576	dpm_show_time(starttime, state, error, info: "noirq");
1577	trace_suspend_resume(TPS("dpm_suspend_noirq"), val: state.event, start: false);
1578	return error;
1579	}
1580
1581	/**
1582	* dpm_suspend_noirq - Execute "noirq suspend" callbacks for all devices.
1583	* @state: PM transition of the system being carried out.
1584	*
1585	* Prevent device drivers' interrupt handlers from being called and invoke
1586	* "noirq" suspend callbacks for all non-sysdev devices.
1587	*/
1588	int dpm_suspend_noirq(pm_message_t state)
1589	{
1590	int ret;
1591
1592	device_wakeup_arm_wake_irqs();
1593	suspend_device_irqs();
1594
1595	ret = dpm_noirq_suspend_devices(state);
1596	if (ret)
1597	dpm_resume_noirq(state: resume_event(sleep_state: state));
1598
1599	return ret;
1600	}
1601
1602	static void dpm_propagate_wakeup_to_parent(struct device *dev)
1603	{
1604	struct device *parent = dev->parent;
1605
1606	if (!parent)
1607	return;
1608
1609	spin_lock_irq(lock: &parent->power.lock);
1610
1611	if (device_wakeup_path(dev) && !parent->power.ignore_children)
1612	parent->power.wakeup_path = true;
1613
1614	spin_unlock_irq(lock: &parent->power.lock);
1615	}
1616
1617	static void async_suspend_late(void *data, async_cookie_t cookie);
1618
1619	/**
1620	* device_suspend_late - Execute a "late suspend" callback for given device.
1621	* @dev: Device to handle.
1622	* @state: PM transition of the system being carried out.
1623	* @async: If true, the device is being suspended asynchronously.
1624	*
1625	* Runtime PM is disabled for @dev while this function is being executed.
1626	*/
1627	static void device_suspend_late(struct device *dev, pm_message_t state, bool async)
1628	{
1629	pm_callback_t callback = NULL;
1630	const char *info = NULL;
1631	int error = 0;
1632
1633	TRACE_DEVICE(dev);
1634	TRACE_SUSPEND(0);
1635
1636	dpm_wait_for_subordinate(dev, async);
1637
1638	if (READ_ONCE(async_error))
1639	goto Complete;
1640
1641	if (pm_wakeup_pending()) {
1642	WRITE_ONCE(async_error, -EBUSY);
1643	goto Complete;
1644	}
1645
1646	if (dev->power.direct_complete)
1647	goto Complete;
1648
1649	/*
1650	* Disable runtime PM for the device without checking if there is a
1651	* pending resume request for it.
1652	*/
1653	__pm_runtime_disable(dev, check_resume: false);
1654
1655	if (dev->power.syscore)
1656	goto Skip;
1657
1658	if (dev->pm_domain) {
1659	info = "late power domain ";
1660	callback = pm_late_early_op(ops: &dev->pm_domain->ops, state);
1661	} else if (dev->type && dev->type->pm) {
1662	info = "late type ";
1663	callback = pm_late_early_op(ops: dev->type->pm, state);
1664	} else if (dev->class && dev->class->pm) {
1665	info = "late class ";
1666	callback = pm_late_early_op(ops: dev->class->pm, state);
1667	} else if (dev->bus && dev->bus->pm) {
1668	info = "late bus ";
1669	callback = pm_late_early_op(ops: dev->bus->pm, state);
1670	}
1671	if (callback)
1672	goto Run;
1673
1674	if (dev_pm_skip_suspend(dev))
1675	goto Skip;
1676
1677	if (dev->driver && dev->driver->pm) {
1678	info = "late driver ";
1679	callback = pm_late_early_op(ops: dev->driver->pm, state);
1680	}
1681
1682	Run:
1683	error = dpm_run_callback(cb: callback, dev, state, info);
1684	if (error) {
1685	WRITE_ONCE(async_error, error);
1686	dpm_save_failed_dev(name: dev_name(dev));
1687	pm_dev_err(dev, state, info: async ? " async late" : " late", error);
1688	pm_runtime_enable(dev);
1689	goto Complete;
1690	}
1691	dpm_propagate_wakeup_to_parent(dev);
1692
1693	Skip:
1694	dev->power.is_late_suspended = true;
1695
1696	Complete:
1697	TRACE_SUSPEND(error);
1698	complete_all(&dev->power.completion);
1699
1700	if (error || READ_ONCE(async_error))
1701	return;
1702
1703	dpm_async_suspend_superior(dev, func: async_suspend_late);
1704	}
1705
1706	static void async_suspend_late(void *data, async_cookie_t cookie)
1707	{
1708	struct device *dev = data;
1709
1710	device_suspend_late(dev, state: pm_transition, async: true);
1711	put_device(dev);
1712	}
1713
1714	/**
1715	* dpm_suspend_late - Execute "late suspend" callbacks for all devices.
1716	* @state: PM transition of the system being carried out.
1717	*/
1718	int dpm_suspend_late(pm_message_t state)
1719	{
1720	ktime_t starttime = ktime_get();
1721	struct device *dev;
1722	int error;
1723
1724	trace_suspend_resume(TPS("dpm_suspend_late"), val: state.event, start: true);
1725
1726	pm_transition = state;
1727	async_error = 0;
1728
1729	wake_up_all_idle_cpus();
1730
1731	mutex_lock(&dpm_list_mtx);
1732
1733	/*
1734	* Start processing "async" leaf devices upfront so they don't need to
1735	* wait for the "sync" devices they don't depend on.
1736	*/
1737	list_for_each_entry_reverse(dev, &dpm_suspended_list, power.entry) {
1738	dpm_clear_async_state(dev);
1739	if (dpm_leaf_device(dev))
1740	dpm_async_with_cleanup(dev, fn: async_suspend_late);
1741	}
1742
1743	while (!list_empty(head: &dpm_suspended_list)) {
1744	dev = to_device(entry: dpm_suspended_list.prev);
1745
1746	list_move(list: &dev->power.entry, head: &dpm_late_early_list);
1747
1748	if (dpm_async_fn(dev, func: async_suspend_late))
1749	continue;
1750
1751	get_device(dev);
1752
1753	mutex_unlock(lock: &dpm_list_mtx);
1754
1755	device_suspend_late(dev, state, async: false);
1756
1757	put_device(dev);
1758
1759	mutex_lock(&dpm_list_mtx);
1760
1761	if (READ_ONCE(async_error)) {
1762	dpm_async_suspend_complete_all(device_list: &dpm_suspended_list);
1763	/*
1764	* Move all devices to the target list to resume them
1765	* properly.
1766	*/
1767	list_splice_init(list: &dpm_suspended_list, head: &dpm_late_early_list);
1768	break;
1769	}
1770	}
1771
1772	mutex_unlock(lock: &dpm_list_mtx);
1773
1774	async_synchronize_full();
1775
1776	error = READ_ONCE(async_error);
1777	if (error) {
1778	dpm_save_failed_step(step: SUSPEND_SUSPEND_LATE);
1779	dpm_resume_early(state: resume_event(sleep_state: state));
1780	}
1781	dpm_show_time(starttime, state, error, info: "late");
1782	trace_suspend_resume(TPS("dpm_suspend_late"), val: state.event, start: false);
1783	return error;
1784	}
1785
1786	/**
1787	* dpm_suspend_end - Execute "late" and "noirq" device suspend callbacks.
1788	* @state: PM transition of the system being carried out.
1789	*/
1790	int dpm_suspend_end(pm_message_t state)
1791	{
1792	ktime_t starttime = ktime_get();
1793	int error;
1794
1795	error = dpm_suspend_late(state);
1796	if (error)
1797	goto out;
1798
1799	error = dpm_suspend_noirq(state);
1800	if (error)
1801	dpm_resume_early(state: resume_event(sleep_state: state));
1802
1803	out:
1804	dpm_show_time(starttime, state, error, info: "end");
1805	return error;
1806	}
1807	EXPORT_SYMBOL_GPL(dpm_suspend_end);
1808
1809	/**
1810	* legacy_suspend - Execute a legacy (bus or class) suspend callback for device.
1811	* @dev: Device to suspend.
1812	* @state: PM transition of the system being carried out.
1813	* @cb: Suspend callback to execute.
1814	* @info: string description of caller.
1815	*/
1816	static int legacy_suspend(struct device *dev, pm_message_t state,
1817	int (*cb)(struct device *dev, pm_message_t state),
1818	const char *info)
1819	{
1820	int error;
1821	ktime_t calltime;
1822
1823	calltime = initcall_debug_start(dev, cb);
1824
1825	trace_device_pm_callback_start(dev, pm_ops: info, event: state.event);
1826	error = cb(dev, state);
1827	trace_device_pm_callback_end(dev, error);
1828	suspend_report_result(dev, cb, error);
1829
1830	initcall_debug_report(dev, calltime, cb, error);
1831
1832	return error;
1833	}
1834
1835	static void dpm_clear_superiors_direct_complete(struct device *dev)
1836	{
1837	struct device_link *link;
1838	int idx;
1839
1840	if (dev->parent) {
1841	spin_lock_irq(lock: &dev->parent->power.lock);
1842	dev->parent->power.direct_complete = false;
1843	spin_unlock_irq(lock: &dev->parent->power.lock);
1844	}
1845
1846	idx = device_links_read_lock();
1847
1848	dev_for_each_link_to_supplier(link, dev) {
1849	spin_lock_irq(lock: &link->supplier->power.lock);
1850	link->supplier->power.direct_complete = false;
1851	spin_unlock_irq(lock: &link->supplier->power.lock);
1852	}
1853
1854	device_links_read_unlock(idx);
1855	}
1856
1857	static void async_suspend(void *data, async_cookie_t cookie);
1858
1859	/**
1860	* device_suspend - Execute "suspend" callbacks for given device.
1861	* @dev: Device to handle.
1862	* @state: PM transition of the system being carried out.
1863	* @async: If true, the device is being suspended asynchronously.
1864	*/
1865	static void device_suspend(struct device *dev, pm_message_t state, bool async)
1866	{
1867	pm_callback_t callback = NULL;
1868	const char *info = NULL;
1869	int error = 0;
1870	DECLARE_DPM_WATCHDOG_ON_STACK(wd);
1871
1872	TRACE_DEVICE(dev);
1873	TRACE_SUSPEND(0);
1874
1875	dpm_wait_for_subordinate(dev, async);
1876
1877	if (READ_ONCE(async_error)) {
1878	dev->power.direct_complete = false;
1879	goto Complete;
1880	}
1881
1882	/*
1883	* Wait for possible runtime PM transitions of the device in progress
1884	* to complete and if there's a runtime resume request pending for it,
1885	* resume it before proceeding with invoking the system-wide suspend
1886	* callbacks for it.
1887	*
1888	* If the system-wide suspend callbacks below change the configuration
1889	* of the device, they must disable runtime PM for it or otherwise
1890	* ensure that its runtime-resume callbacks will not be confused by that
1891	* change in case they are invoked going forward.
1892	*/
1893	pm_runtime_barrier(dev);
1894
1895	if (pm_wakeup_pending()) {
1896	dev->power.direct_complete = false;
1897	WRITE_ONCE(async_error, -EBUSY);
1898	goto Complete;
1899	}
1900
1901	if (dev->power.syscore)
1902	goto Complete;
1903
1904	/* Avoid direct_complete to let wakeup_path propagate. */
1905	if (device_may_wakeup(dev) || device_wakeup_path(dev))
1906	dev->power.direct_complete = false;
1907
1908	if (dev->power.direct_complete) {
1909	if (pm_runtime_status_suspended(dev)) {
1910	pm_runtime_disable(dev);
1911	if (pm_runtime_status_suspended(dev)) {
1912	pm_dev_dbg(dev, state, info: "direct-complete ");
1913	dev->power.is_suspended = true;
1914	goto Complete;
1915	}
1916
1917	pm_runtime_enable(dev);
1918	}
1919	dev->power.direct_complete = false;
1920	}
1921
1922	dev->power.may_skip_resume = true;
1923	dev->power.must_resume = !dev_pm_test_driver_flags(dev, DPM_FLAG_MAY_SKIP_RESUME);
1924
1925	dpm_watchdog_set(wd: &wd, dev);
1926	device_lock(dev);
1927
1928	if (dev->pm_domain) {
1929	info = "power domain ";
1930	callback = pm_op(ops: &dev->pm_domain->ops, state);
1931	goto Run;
1932	}
1933
1934	if (dev->type && dev->type->pm) {
1935	info = "type ";
1936	callback = pm_op(ops: dev->type->pm, state);
1937	goto Run;
1938	}
1939
1940	if (dev->class && dev->class->pm) {
1941	info = "class ";
1942	callback = pm_op(ops: dev->class->pm, state);
1943	goto Run;
1944	}
1945
1946	if (dev->bus) {
1947	if (dev->bus->pm) {
1948	info = "bus ";
1949	callback = pm_op(ops: dev->bus->pm, state);
1950	} else if (dev->bus->suspend) {
1951	pm_dev_dbg(dev, state, info: "legacy bus ");
1952	error = legacy_suspend(dev, state, cb: dev->bus->suspend,
1953	info: "legacy bus ");
1954	goto End;
1955	}
1956	}
1957
1958	Run:
1959	if (!callback && dev->driver && dev->driver->pm) {
1960	info = "driver ";
1961	callback = pm_op(ops: dev->driver->pm, state);
1962	}
1963
1964	error = dpm_run_callback(cb: callback, dev, state, info);
1965
1966	End:
1967	if (!error) {
1968	dev->power.is_suspended = true;
1969	if (device_may_wakeup(dev))
1970	dev->power.wakeup_path = true;
1971
1972	dpm_propagate_wakeup_to_parent(dev);
1973	dpm_clear_superiors_direct_complete(dev);
1974	}
1975
1976	device_unlock(dev);
1977	dpm_watchdog_clear(wd: &wd);
1978
1979	Complete:
1980	if (error) {
1981	WRITE_ONCE(async_error, error);
1982	dpm_save_failed_dev(name: dev_name(dev));
1983	pm_dev_err(dev, state, info: async ? " async" : "", error);
1984	}
1985
1986	complete_all(&dev->power.completion);
1987	TRACE_SUSPEND(error);
1988
1989	if (error || READ_ONCE(async_error))
1990	return;
1991
1992	dpm_async_suspend_superior(dev, func: async_suspend);
1993	}
1994
1995	static void async_suspend(void *data, async_cookie_t cookie)
1996	{
1997	struct device *dev = data;
1998
1999	device_suspend(dev, state: pm_transition, async: true);
2000	put_device(dev);
2001	}
2002
2003	/**
2004	* dpm_suspend - Execute "suspend" callbacks for all non-sysdev devices.
2005	* @state: PM transition of the system being carried out.
2006	*/
2007	int dpm_suspend(pm_message_t state)
2008	{
2009	ktime_t starttime = ktime_get();
2010	struct device *dev;
2011	int error;
2012
2013	trace_suspend_resume(TPS("dpm_suspend"), val: state.event, start: true);
2014	might_sleep();
2015
2016	devfreq_suspend();
2017	cpufreq_suspend();
2018
2019	pm_transition = state;
2020	async_error = 0;
2021
2022	mutex_lock(&dpm_list_mtx);
2023
2024	/*
2025	* Start processing "async" leaf devices upfront so they don't need to
2026	* wait for the "sync" devices they don't depend on.
2027	*/
2028	list_for_each_entry_reverse(dev, &dpm_prepared_list, power.entry) {
2029	dpm_clear_async_state(dev);
2030	if (dpm_leaf_device(dev))
2031	dpm_async_with_cleanup(dev, fn: async_suspend);
2032	}
2033
2034	while (!list_empty(head: &dpm_prepared_list)) {
2035	dev = to_device(entry: dpm_prepared_list.prev);
2036
2037	list_move(list: &dev->power.entry, head: &dpm_suspended_list);
2038
2039	if (dpm_async_fn(dev, func: async_suspend))
2040	continue;
2041
2042	get_device(dev);
2043
2044	mutex_unlock(lock: &dpm_list_mtx);
2045
2046	device_suspend(dev, state, async: false);
2047
2048	put_device(dev);
2049
2050	mutex_lock(&dpm_list_mtx);
2051
2052	if (READ_ONCE(async_error)) {
2053	dpm_async_suspend_complete_all(device_list: &dpm_prepared_list);
2054	/*
2055	* Move all devices to the target list to resume them
2056	* properly.
2057	*/
2058	list_splice_init(list: &dpm_prepared_list, head: &dpm_suspended_list);
2059	break;
2060	}
2061	}
2062
2063	mutex_unlock(lock: &dpm_list_mtx);
2064
2065	async_synchronize_full();
2066
2067	error = READ_ONCE(async_error);
2068	if (error)
2069	dpm_save_failed_step(step: SUSPEND_SUSPEND);
2070
2071	dpm_show_time(starttime, state, error, NULL);
2072	trace_suspend_resume(TPS("dpm_suspend"), val: state.event, start: false);
2073	return error;
2074	}
2075
2076	static bool device_prepare_smart_suspend(struct device *dev)
2077	{
2078	struct device_link *link;
2079	bool ret = true;
2080	int idx;
2081
2082	/*
2083	* The "smart suspend" feature is enabled for devices whose drivers ask
2084	* for it and for devices without PM callbacks.
2085	*
2086	* However, if "smart suspend" is not enabled for the device's parent
2087	* or any of its suppliers that take runtime PM into account, it cannot
2088	* be enabled for the device either.
2089	*/
2090	if (!dev->power.no_pm_callbacks &&
2091	!dev_pm_test_driver_flags(dev, DPM_FLAG_SMART_SUSPEND))
2092	return false;
2093
2094	if (dev->parent && !dev_pm_smart_suspend(dev: dev->parent) &&
2095	!dev->parent->power.ignore_children && !pm_runtime_blocked(dev: dev->parent))
2096	return false;
2097
2098	idx = device_links_read_lock();
2099
2100	dev_for_each_link_to_supplier(link, dev) {
2101	if (!device_link_test(link, DL_FLAG_PM_RUNTIME))
2102	continue;
2103
2104	if (!dev_pm_smart_suspend(dev: link->supplier) &&
2105	!pm_runtime_blocked(dev: link->supplier)) {
2106	ret = false;
2107	break;
2108	}
2109	}
2110
2111	device_links_read_unlock(idx);
2112
2113	return ret;
2114	}
2115
2116	/**
2117	* device_prepare - Prepare a device for system power transition.
2118	* @dev: Device to handle.
2119	* @state: PM transition of the system being carried out.
2120	*
2121	* Execute the ->prepare() callback(s) for given device. No new children of the
2122	* device may be registered after this function has returned.
2123	*/
2124	static int device_prepare(struct device *dev, pm_message_t state)
2125	{
2126	int (*callback)(struct device *) = NULL;
2127	bool smart_suspend;
2128	int ret = 0;
2129
2130	/*
2131	* If a device's parent goes into runtime suspend at the wrong time,
2132	* it won't be possible to resume the device. To prevent this we
2133	* block runtime suspend here, during the prepare phase, and allow
2134	* it again during the complete phase.
2135	*/
2136	pm_runtime_get_noresume(dev);
2137	/*
2138	* If runtime PM is disabled for the device at this point and it has
2139	* never been enabled so far, it should not be enabled until this system
2140	* suspend-resume cycle is complete, so prepare to trigger a warning on
2141	* subsequent attempts to enable it.
2142	*/
2143	smart_suspend = !pm_runtime_block_if_disabled(dev);
2144
2145	if (dev->power.syscore)
2146	return 0;
2147
2148	device_lock(dev);
2149
2150	dev->power.wakeup_path = false;
2151	dev->power.out_band_wakeup = false;
2152
2153	if (dev->power.no_pm_callbacks)
2154	goto unlock;
2155
2156	if (dev->pm_domain)
2157	callback = dev->pm_domain->ops.prepare;
2158	else if (dev->type && dev->type->pm)
2159	callback = dev->type->pm->prepare;
2160	else if (dev->class && dev->class->pm)
2161	callback = dev->class->pm->prepare;
2162	else if (dev->bus && dev->bus->pm)
2163	callback = dev->bus->pm->prepare;
2164
2165	if (!callback && dev->driver && dev->driver->pm)
2166	callback = dev->driver->pm->prepare;
2167
2168	if (callback)
2169	ret = callback(dev);
2170
2171	unlock:
2172	device_unlock(dev);
2173
2174	if (ret < 0) {
2175	suspend_report_result(dev, callback, ret);
2176	pm_runtime_put(dev);
2177	return ret;
2178	}
2179	/* Do not enable "smart suspend" for devices with disabled runtime PM. */
2180	if (smart_suspend)
2181	smart_suspend = device_prepare_smart_suspend(dev);
2182
2183	spin_lock_irq(lock: &dev->power.lock);
2184
2185	dev->power.smart_suspend = smart_suspend;
2186	/*
2187	* A positive return value from ->prepare() means "this device appears
2188	* to be runtime-suspended and its state is fine, so if it really is
2189	* runtime-suspended, you can leave it in that state provided that you
2190	* will do the same thing with all of its descendants". This only
2191	* applies to suspend transitions, however.
2192	*/
2193	dev->power.direct_complete = state.event == PM_EVENT_SUSPEND &&
2194	(ret > 0 || dev->power.no_pm_callbacks) &&
2195	!dev_pm_test_driver_flags(dev, DPM_FLAG_NO_DIRECT_COMPLETE);
2196
2197	spin_unlock_irq(lock: &dev->power.lock);
2198
2199	return 0;
2200	}
2201
2202	/**
2203	* dpm_prepare - Prepare all non-sysdev devices for a system PM transition.
2204	* @state: PM transition of the system being carried out.
2205	*
2206	* Execute the ->prepare() callback(s) for all devices.
2207	*/
2208	int dpm_prepare(pm_message_t state)
2209	{
2210	int error = 0;
2211
2212	trace_suspend_resume(TPS("dpm_prepare"), val: state.event, start: true);
2213
2214	/*
2215	* Give a chance for the known devices to complete their probes, before
2216	* disable probing of devices. This sync point is important at least
2217	* at boot time + hibernation restore.
2218	*/
2219	wait_for_device_probe();
2220	/*
2221	* It is unsafe if probing of devices will happen during suspend or
2222	* hibernation and system behavior will be unpredictable in this case.
2223	* So, let's prohibit device's probing here and defer their probes
2224	* instead. The normal behavior will be restored in dpm_complete().
2225	*/
2226	device_block_probing();
2227
2228	mutex_lock(&dpm_list_mtx);
2229	while (!list_empty(head: &dpm_list) && !error) {
2230	struct device *dev = to_device(entry: dpm_list.next);
2231
2232	get_device(dev);
2233
2234	mutex_unlock(lock: &dpm_list_mtx);
2235
2236	trace_device_pm_callback_start(dev, pm_ops: "", event: state.event);
2237	error = device_prepare(dev, state);
2238	trace_device_pm_callback_end(dev, error);
2239
2240	mutex_lock(&dpm_list_mtx);
2241
2242	if (!error) {
2243	dev->power.is_prepared = true;
2244	if (!list_empty(head: &dev->power.entry))
2245	list_move_tail(list: &dev->power.entry, head: &dpm_prepared_list);
2246	} else if (error == -EAGAIN) {
2247	error = 0;
2248	} else {
2249	dev_info(dev, "not prepared for power transition: code %d\n",
2250	error);
2251	}
2252
2253	mutex_unlock(lock: &dpm_list_mtx);
2254
2255	put_device(dev);
2256
2257	mutex_lock(&dpm_list_mtx);
2258	}
2259	mutex_unlock(lock: &dpm_list_mtx);
2260	trace_suspend_resume(TPS("dpm_prepare"), val: state.event, start: false);
2261	return error;
2262	}
2263
2264	/**
2265	* dpm_suspend_start - Prepare devices for PM transition and suspend them.
2266	* @state: PM transition of the system being carried out.
2267	*
2268	* Prepare all non-sysdev devices for system PM transition and execute "suspend"
2269	* callbacks for them.
2270	*/
2271	int dpm_suspend_start(pm_message_t state)
2272	{
2273	ktime_t starttime = ktime_get();
2274	int error;
2275
2276	error = dpm_prepare(state);
2277	if (error)
2278	dpm_save_failed_step(step: SUSPEND_PREPARE);
2279	else {
2280	pm_restrict_gfp_mask();
2281	error = dpm_suspend(state);
2282	}
2283
2284	dpm_show_time(starttime, state, error, info: "start");
2285	return error;
2286	}
2287	EXPORT_SYMBOL_GPL(dpm_suspend_start);
2288
2289	void __suspend_report_result(const char *function, struct device *dev, void *fn, int ret)
2290	{
2291	if (ret)
2292	dev_err(dev, "%s(): %ps returns %d\n", function, fn, ret);
2293	}
2294	EXPORT_SYMBOL_GPL(__suspend_report_result);
2295
2296	/**
2297	* device_pm_wait_for_dev - Wait for suspend/resume of a device to complete.
2298	* @subordinate: Device that needs to wait for @dev.
2299	* @dev: Device to wait for.
2300	*/
2301	int device_pm_wait_for_dev(struct device *subordinate, struct device *dev)
2302	{
2303	dpm_wait(dev, async: subordinate->power.async_suspend);
2304	return async_error;
2305	}
2306	EXPORT_SYMBOL_GPL(device_pm_wait_for_dev);
2307
2308	/**
2309	* dpm_for_each_dev - device iterator.
2310	* @data: data for the callback.
2311	* @fn: function to be called for each device.
2312	*
2313	* Iterate over devices in dpm_list, and call @fn for each device,
2314	* passing it @data.
2315	*/
2316	void dpm_for_each_dev(void *data, void (*fn)(struct device *, void *))
2317	{
2318	struct device *dev;
2319
2320	if (!fn)
2321	return;
2322
2323	device_pm_lock();
2324	list_for_each_entry(dev, &dpm_list, power.entry)
2325	fn(dev, data);
2326	device_pm_unlock();
2327	}
2328	EXPORT_SYMBOL_GPL(dpm_for_each_dev);
2329
2330	static bool pm_ops_is_empty(const struct dev_pm_ops *ops)
2331	{
2332	if (!ops)
2333	return true;
2334
2335	return !ops->prepare &&
2336	!ops->suspend &&
2337	!ops->suspend_late &&
2338	!ops->suspend_noirq &&
2339	!ops->resume_noirq &&
2340	!ops->resume_early &&
2341	!ops->resume &&
2342	!ops->complete;
2343	}
2344
2345	void device_pm_check_callbacks(struct device *dev)
2346	{
2347	unsigned long flags;
2348
2349	spin_lock_irqsave(&dev->power.lock, flags);
2350	dev->power.no_pm_callbacks =
2351	(!dev->bus || (pm_ops_is_empty(ops: dev->bus->pm) &&
2352	!dev->bus->suspend && !dev->bus->resume)) &&
2353	(!dev->class || pm_ops_is_empty(ops: dev->class->pm)) &&
2354	(!dev->type || pm_ops_is_empty(ops: dev->type->pm)) &&
2355	(!dev->pm_domain || pm_ops_is_empty(ops: &dev->pm_domain->ops)) &&
2356	(!dev->driver || (pm_ops_is_empty(ops: dev->driver->pm) &&
2357	!dev->driver->suspend && !dev->driver->resume));
2358	spin_unlock_irqrestore(lock: &dev->power.lock, flags);
2359	}
2360
2361	bool dev_pm_skip_suspend(struct device *dev)
2362	{
2363	return dev_pm_smart_suspend(dev) && pm_runtime_status_suspended(dev);
2364	}
2365