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v5.9
  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * kernel/power/main.c - PM subsystem core functionality.
  4 *
  5 * Copyright (c) 2003 Patrick Mochel
  6 * Copyright (c) 2003 Open Source Development Lab
 
 
 
  7 */
  8
  9#include <linux/export.h>
 10#include <linux/kobject.h>
 11#include <linux/string.h>
 12#include <linux/pm-trace.h>
 13#include <linux/workqueue.h>
 14#include <linux/debugfs.h>
 15#include <linux/seq_file.h>
 16#include <linux/suspend.h>
 17#include <linux/syscalls.h>
 18#include <linux/pm_runtime.h>
 19
 20#include "power.h"
 21
 
 
 22#ifdef CONFIG_PM_SLEEP
 23
 24void lock_system_sleep(void)
 25{
 26	current->flags |= PF_FREEZER_SKIP;
 27	mutex_lock(&system_transition_mutex);
 28}
 29EXPORT_SYMBOL_GPL(lock_system_sleep);
 30
 31void unlock_system_sleep(void)
 32{
 33	/*
 34	 * Don't use freezer_count() because we don't want the call to
 35	 * try_to_freeze() here.
 36	 *
 37	 * Reason:
 38	 * Fundamentally, we just don't need it, because freezing condition
 39	 * doesn't come into effect until we release the
 40	 * system_transition_mutex lock, since the freezer always works with
 41	 * system_transition_mutex held.
 42	 *
 43	 * More importantly, in the case of hibernation,
 44	 * unlock_system_sleep() gets called in snapshot_read() and
 45	 * snapshot_write() when the freezing condition is still in effect.
 46	 * Which means, if we use try_to_freeze() here, it would make them
 47	 * enter the refrigerator, thus causing hibernation to lockup.
 48	 */
 49	current->flags &= ~PF_FREEZER_SKIP;
 50	mutex_unlock(&system_transition_mutex);
 51}
 52EXPORT_SYMBOL_GPL(unlock_system_sleep);
 53
 54void ksys_sync_helper(void)
 55{
 56	ktime_t start;
 57	long elapsed_msecs;
 58
 59	start = ktime_get();
 60	ksys_sync();
 61	elapsed_msecs = ktime_to_ms(ktime_sub(ktime_get(), start));
 62	pr_info("Filesystems sync: %ld.%03ld seconds\n",
 63		elapsed_msecs / MSEC_PER_SEC, elapsed_msecs % MSEC_PER_SEC);
 64}
 65EXPORT_SYMBOL_GPL(ksys_sync_helper);
 66
 67/* Routines for PM-transition notifications */
 68
 69static BLOCKING_NOTIFIER_HEAD(pm_chain_head);
 70
 71int register_pm_notifier(struct notifier_block *nb)
 72{
 73	return blocking_notifier_chain_register(&pm_chain_head, nb);
 74}
 75EXPORT_SYMBOL_GPL(register_pm_notifier);
 76
 77int unregister_pm_notifier(struct notifier_block *nb)
 78{
 79	return blocking_notifier_chain_unregister(&pm_chain_head, nb);
 80}
 81EXPORT_SYMBOL_GPL(unregister_pm_notifier);
 82
 83int __pm_notifier_call_chain(unsigned long val, int nr_to_call, int *nr_calls)
 84{
 85	int ret;
 86
 87	ret = __blocking_notifier_call_chain(&pm_chain_head, val, NULL,
 88						nr_to_call, nr_calls);
 89
 90	return notifier_to_errno(ret);
 91}
 92int pm_notifier_call_chain(unsigned long val)
 93{
 94	return __pm_notifier_call_chain(val, -1, NULL);
 95}
 96
 97/* If set, devices may be suspended and resumed asynchronously. */
 98int pm_async_enabled = 1;
 99
100static ssize_t pm_async_show(struct kobject *kobj, struct kobj_attribute *attr,
101			     char *buf)
102{
103	return sprintf(buf, "%d\n", pm_async_enabled);
104}
105
106static ssize_t pm_async_store(struct kobject *kobj, struct kobj_attribute *attr,
107			      const char *buf, size_t n)
108{
109	unsigned long val;
110
111	if (kstrtoul(buf, 10, &val))
112		return -EINVAL;
113
114	if (val > 1)
115		return -EINVAL;
116
117	pm_async_enabled = val;
118	return n;
119}
120
121power_attr(pm_async);
122
123#ifdef CONFIG_SUSPEND
124static ssize_t mem_sleep_show(struct kobject *kobj, struct kobj_attribute *attr,
125			      char *buf)
126{
127	char *s = buf;
128	suspend_state_t i;
129
130	for (i = PM_SUSPEND_MIN; i < PM_SUSPEND_MAX; i++)
131		if (mem_sleep_states[i]) {
132			const char *label = mem_sleep_states[i];
133
134			if (mem_sleep_current == i)
135				s += sprintf(s, "[%s] ", label);
136			else
137				s += sprintf(s, "%s ", label);
138		}
139
140	/* Convert the last space to a newline if needed. */
141	if (s != buf)
142		*(s-1) = '\n';
143
144	return (s - buf);
145}
146
147static suspend_state_t decode_suspend_state(const char *buf, size_t n)
148{
149	suspend_state_t state;
150	char *p;
151	int len;
152
153	p = memchr(buf, '\n', n);
154	len = p ? p - buf : n;
155
156	for (state = PM_SUSPEND_MIN; state < PM_SUSPEND_MAX; state++) {
157		const char *label = mem_sleep_states[state];
158
159		if (label && len == strlen(label) && !strncmp(buf, label, len))
160			return state;
161	}
162
163	return PM_SUSPEND_ON;
164}
165
166static ssize_t mem_sleep_store(struct kobject *kobj, struct kobj_attribute *attr,
167			       const char *buf, size_t n)
168{
169	suspend_state_t state;
170	int error;
171
172	error = pm_autosleep_lock();
173	if (error)
174		return error;
175
176	if (pm_autosleep_state() > PM_SUSPEND_ON) {
177		error = -EBUSY;
178		goto out;
179	}
180
181	state = decode_suspend_state(buf, n);
182	if (state < PM_SUSPEND_MAX && state > PM_SUSPEND_ON)
183		mem_sleep_current = state;
184	else
185		error = -EINVAL;
186
187 out:
188	pm_autosleep_unlock();
189	return error ? error : n;
190}
191
192power_attr(mem_sleep);
193
194/*
195 * sync_on_suspend: invoke ksys_sync_helper() before suspend.
196 *
197 * show() returns whether ksys_sync_helper() is invoked before suspend.
198 * store() accepts 0 or 1.  0 disables ksys_sync_helper() and 1 enables it.
199 */
200bool sync_on_suspend_enabled = !IS_ENABLED(CONFIG_SUSPEND_SKIP_SYNC);
201
202static ssize_t sync_on_suspend_show(struct kobject *kobj,
203				   struct kobj_attribute *attr, char *buf)
204{
205	return sprintf(buf, "%d\n", sync_on_suspend_enabled);
206}
207
208static ssize_t sync_on_suspend_store(struct kobject *kobj,
209				    struct kobj_attribute *attr,
210				    const char *buf, size_t n)
211{
212	unsigned long val;
213
214	if (kstrtoul(buf, 10, &val))
215		return -EINVAL;
216
217	if (val > 1)
218		return -EINVAL;
219
220	sync_on_suspend_enabled = !!val;
221	return n;
222}
223
224power_attr(sync_on_suspend);
225#endif /* CONFIG_SUSPEND */
226
227#ifdef CONFIG_PM_SLEEP_DEBUG
228int pm_test_level = TEST_NONE;
229
230static const char * const pm_tests[__TEST_AFTER_LAST] = {
231	[TEST_NONE] = "none",
232	[TEST_CORE] = "core",
233	[TEST_CPUS] = "processors",
234	[TEST_PLATFORM] = "platform",
235	[TEST_DEVICES] = "devices",
236	[TEST_FREEZER] = "freezer",
237};
238
239static ssize_t pm_test_show(struct kobject *kobj, struct kobj_attribute *attr,
240				char *buf)
241{
242	char *s = buf;
243	int level;
244
245	for (level = TEST_FIRST; level <= TEST_MAX; level++)
246		if (pm_tests[level]) {
247			if (level == pm_test_level)
248				s += sprintf(s, "[%s] ", pm_tests[level]);
249			else
250				s += sprintf(s, "%s ", pm_tests[level]);
251		}
252
253	if (s != buf)
254		/* convert the last space to a newline */
255		*(s-1) = '\n';
256
257	return (s - buf);
258}
259
260static ssize_t pm_test_store(struct kobject *kobj, struct kobj_attribute *attr,
261				const char *buf, size_t n)
262{
263	const char * const *s;
264	int level;
265	char *p;
266	int len;
267	int error = -EINVAL;
268
269	p = memchr(buf, '\n', n);
270	len = p ? p - buf : n;
271
272	lock_system_sleep();
273
274	level = TEST_FIRST;
275	for (s = &pm_tests[level]; level <= TEST_MAX; s++, level++)
276		if (*s && len == strlen(*s) && !strncmp(buf, *s, len)) {
277			pm_test_level = level;
278			error = 0;
279			break;
280		}
281
282	unlock_system_sleep();
283
284	return error ? error : n;
285}
286
287power_attr(pm_test);
288#endif /* CONFIG_PM_SLEEP_DEBUG */
289
 
290static char *suspend_step_name(enum suspend_stat_step step)
291{
292	switch (step) {
293	case SUSPEND_FREEZE:
294		return "freeze";
295	case SUSPEND_PREPARE:
296		return "prepare";
297	case SUSPEND_SUSPEND:
298		return "suspend";
299	case SUSPEND_SUSPEND_NOIRQ:
300		return "suspend_noirq";
301	case SUSPEND_RESUME_NOIRQ:
302		return "resume_noirq";
303	case SUSPEND_RESUME:
304		return "resume";
305	default:
306		return "";
307	}
308}
309
310#define suspend_attr(_name)					\
311static ssize_t _name##_show(struct kobject *kobj,		\
312		struct kobj_attribute *attr, char *buf)		\
313{								\
314	return sprintf(buf, "%d\n", suspend_stats._name);	\
315}								\
316static struct kobj_attribute _name = __ATTR_RO(_name)
317
318suspend_attr(success);
319suspend_attr(fail);
320suspend_attr(failed_freeze);
321suspend_attr(failed_prepare);
322suspend_attr(failed_suspend);
323suspend_attr(failed_suspend_late);
324suspend_attr(failed_suspend_noirq);
325suspend_attr(failed_resume);
326suspend_attr(failed_resume_early);
327suspend_attr(failed_resume_noirq);
328
329static ssize_t last_failed_dev_show(struct kobject *kobj,
330		struct kobj_attribute *attr, char *buf)
331{
332	int index;
333	char *last_failed_dev = NULL;
334
335	index = suspend_stats.last_failed_dev + REC_FAILED_NUM - 1;
336	index %= REC_FAILED_NUM;
337	last_failed_dev = suspend_stats.failed_devs[index];
338
339	return sprintf(buf, "%s\n", last_failed_dev);
340}
341static struct kobj_attribute last_failed_dev = __ATTR_RO(last_failed_dev);
342
343static ssize_t last_failed_errno_show(struct kobject *kobj,
344		struct kobj_attribute *attr, char *buf)
345{
346	int index;
347	int last_failed_errno;
348
349	index = suspend_stats.last_failed_errno + REC_FAILED_NUM - 1;
350	index %= REC_FAILED_NUM;
351	last_failed_errno = suspend_stats.errno[index];
352
353	return sprintf(buf, "%d\n", last_failed_errno);
354}
355static struct kobj_attribute last_failed_errno = __ATTR_RO(last_failed_errno);
356
357static ssize_t last_failed_step_show(struct kobject *kobj,
358		struct kobj_attribute *attr, char *buf)
359{
360	int index;
361	enum suspend_stat_step step;
362	char *last_failed_step = NULL;
363
364	index = suspend_stats.last_failed_step + REC_FAILED_NUM - 1;
365	index %= REC_FAILED_NUM;
366	step = suspend_stats.failed_steps[index];
367	last_failed_step = suspend_step_name(step);
368
369	return sprintf(buf, "%s\n", last_failed_step);
370}
371static struct kobj_attribute last_failed_step = __ATTR_RO(last_failed_step);
372
373static struct attribute *suspend_attrs[] = {
374	&success.attr,
375	&fail.attr,
376	&failed_freeze.attr,
377	&failed_prepare.attr,
378	&failed_suspend.attr,
379	&failed_suspend_late.attr,
380	&failed_suspend_noirq.attr,
381	&failed_resume.attr,
382	&failed_resume_early.attr,
383	&failed_resume_noirq.attr,
384	&last_failed_dev.attr,
385	&last_failed_errno.attr,
386	&last_failed_step.attr,
387	NULL,
388};
389
390static struct attribute_group suspend_attr_group = {
391	.name = "suspend_stats",
392	.attrs = suspend_attrs,
393};
394
395#ifdef CONFIG_DEBUG_FS
396static int suspend_stats_show(struct seq_file *s, void *unused)
397{
398	int i, index, last_dev, last_errno, last_step;
399
400	last_dev = suspend_stats.last_failed_dev + REC_FAILED_NUM - 1;
401	last_dev %= REC_FAILED_NUM;
402	last_errno = suspend_stats.last_failed_errno + REC_FAILED_NUM - 1;
403	last_errno %= REC_FAILED_NUM;
404	last_step = suspend_stats.last_failed_step + REC_FAILED_NUM - 1;
405	last_step %= REC_FAILED_NUM;
406	seq_printf(s, "%s: %d\n%s: %d\n%s: %d\n%s: %d\n%s: %d\n"
407			"%s: %d\n%s: %d\n%s: %d\n%s: %d\n%s: %d\n",
408			"success", suspend_stats.success,
409			"fail", suspend_stats.fail,
410			"failed_freeze", suspend_stats.failed_freeze,
411			"failed_prepare", suspend_stats.failed_prepare,
412			"failed_suspend", suspend_stats.failed_suspend,
413			"failed_suspend_late",
414				suspend_stats.failed_suspend_late,
415			"failed_suspend_noirq",
416				suspend_stats.failed_suspend_noirq,
417			"failed_resume", suspend_stats.failed_resume,
418			"failed_resume_early",
419				suspend_stats.failed_resume_early,
420			"failed_resume_noirq",
421				suspend_stats.failed_resume_noirq);
422	seq_printf(s,	"failures:\n  last_failed_dev:\t%-s\n",
423			suspend_stats.failed_devs[last_dev]);
424	for (i = 1; i < REC_FAILED_NUM; i++) {
425		index = last_dev + REC_FAILED_NUM - i;
426		index %= REC_FAILED_NUM;
427		seq_printf(s, "\t\t\t%-s\n",
428			suspend_stats.failed_devs[index]);
429	}
430	seq_printf(s,	"  last_failed_errno:\t%-d\n",
431			suspend_stats.errno[last_errno]);
432	for (i = 1; i < REC_FAILED_NUM; i++) {
433		index = last_errno + REC_FAILED_NUM - i;
434		index %= REC_FAILED_NUM;
435		seq_printf(s, "\t\t\t%-d\n",
436			suspend_stats.errno[index]);
437	}
438	seq_printf(s,	"  last_failed_step:\t%-s\n",
439			suspend_step_name(
440				suspend_stats.failed_steps[last_step]));
441	for (i = 1; i < REC_FAILED_NUM; i++) {
442		index = last_step + REC_FAILED_NUM - i;
443		index %= REC_FAILED_NUM;
444		seq_printf(s, "\t\t\t%-s\n",
445			suspend_step_name(
446				suspend_stats.failed_steps[index]));
447	}
448
449	return 0;
450}
451DEFINE_SHOW_ATTRIBUTE(suspend_stats);
 
 
 
 
 
 
 
 
 
 
 
452
453static int __init pm_debugfs_init(void)
454{
455	debugfs_create_file("suspend_stats", S_IFREG | S_IRUGO,
456			NULL, NULL, &suspend_stats_fops);
457	return 0;
458}
459
460late_initcall(pm_debugfs_init);
461#endif /* CONFIG_DEBUG_FS */
462
463#endif /* CONFIG_PM_SLEEP */
464
465#ifdef CONFIG_PM_SLEEP_DEBUG
466/*
467 * pm_print_times: print time taken by devices to suspend and resume.
468 *
469 * show() returns whether printing of suspend and resume times is enabled.
470 * store() accepts 0 or 1.  0 disables printing and 1 enables it.
471 */
472bool pm_print_times_enabled;
473
474static ssize_t pm_print_times_show(struct kobject *kobj,
475				   struct kobj_attribute *attr, char *buf)
476{
477	return sprintf(buf, "%d\n", pm_print_times_enabled);
478}
479
480static ssize_t pm_print_times_store(struct kobject *kobj,
481				    struct kobj_attribute *attr,
482				    const char *buf, size_t n)
483{
484	unsigned long val;
485
486	if (kstrtoul(buf, 10, &val))
487		return -EINVAL;
488
489	if (val > 1)
490		return -EINVAL;
491
492	pm_print_times_enabled = !!val;
493	return n;
494}
495
496power_attr(pm_print_times);
497
498static inline void pm_print_times_init(void)
499{
500	pm_print_times_enabled = !!initcall_debug;
501}
502
503static ssize_t pm_wakeup_irq_show(struct kobject *kobj,
504					struct kobj_attribute *attr,
505					char *buf)
506{
507	return pm_wakeup_irq ? sprintf(buf, "%u\n", pm_wakeup_irq) : -ENODATA;
508}
509
510power_attr_ro(pm_wakeup_irq);
511
512bool pm_debug_messages_on __read_mostly;
513
514static ssize_t pm_debug_messages_show(struct kobject *kobj,
515				      struct kobj_attribute *attr, char *buf)
516{
517	return sprintf(buf, "%d\n", pm_debug_messages_on);
518}
519
520static ssize_t pm_debug_messages_store(struct kobject *kobj,
521				       struct kobj_attribute *attr,
522				       const char *buf, size_t n)
523{
524	unsigned long val;
525
526	if (kstrtoul(buf, 10, &val))
527		return -EINVAL;
528
529	if (val > 1)
530		return -EINVAL;
531
532	pm_debug_messages_on = !!val;
533	return n;
534}
535
536power_attr(pm_debug_messages);
537
538static int __init pm_debug_messages_setup(char *str)
539{
540	pm_debug_messages_on = true;
541	return 1;
542}
543__setup("pm_debug_messages", pm_debug_messages_setup);
544
545/**
546 * __pm_pr_dbg - Print a suspend debug message to the kernel log.
547 * @defer: Whether or not to use printk_deferred() to print the message.
548 * @fmt: Message format.
549 *
550 * The message will be emitted if enabled through the pm_debug_messages
551 * sysfs attribute.
552 */
553void __pm_pr_dbg(bool defer, const char *fmt, ...)
554{
555	struct va_format vaf;
556	va_list args;
557
558	if (!pm_debug_messages_on)
559		return;
560
561	va_start(args, fmt);
562
563	vaf.fmt = fmt;
564	vaf.va = &args;
565
566	if (defer)
567		printk_deferred(KERN_DEBUG "PM: %pV", &vaf);
568	else
569		printk(KERN_DEBUG "PM: %pV", &vaf);
570
571	va_end(args);
572}
573
574#else /* !CONFIG_PM_SLEEP_DEBUG */
575static inline void pm_print_times_init(void) {}
576#endif /* CONFIG_PM_SLEEP_DEBUG */
577
578struct kobject *power_kobj;
579
580/**
581 * state - control system sleep states.
582 *
583 * show() returns available sleep state labels, which may be "mem", "standby",
584 * "freeze" and "disk" (hibernation).
585 * See Documentation/admin-guide/pm/sleep-states.rst for a description of
586 * what they mean.
587 *
588 * store() accepts one of those strings, translates it into the proper
589 * enumerated value, and initiates a suspend transition.
590 */
591static ssize_t state_show(struct kobject *kobj, struct kobj_attribute *attr,
592			  char *buf)
593{
594	char *s = buf;
595#ifdef CONFIG_SUSPEND
596	suspend_state_t i;
597
598	for (i = PM_SUSPEND_MIN; i < PM_SUSPEND_MAX; i++)
599		if (pm_states[i])
600			s += sprintf(s,"%s ", pm_states[i]);
601
602#endif
603	if (hibernation_available())
604		s += sprintf(s, "disk ");
605	if (s != buf)
606		/* convert the last space to a newline */
607		*(s-1) = '\n';
608	return (s - buf);
609}
610
611static suspend_state_t decode_state(const char *buf, size_t n)
612{
613#ifdef CONFIG_SUSPEND
614	suspend_state_t state;
615#endif
616	char *p;
617	int len;
618
619	p = memchr(buf, '\n', n);
620	len = p ? p - buf : n;
621
622	/* Check hibernation first. */
623	if (len == 4 && str_has_prefix(buf, "disk"))
624		return PM_SUSPEND_MAX;
625
626#ifdef CONFIG_SUSPEND
627	for (state = PM_SUSPEND_MIN; state < PM_SUSPEND_MAX; state++) {
628		const char *label = pm_states[state];
629
630		if (label && len == strlen(label) && !strncmp(buf, label, len))
631			return state;
632	}
633#endif
634
635	return PM_SUSPEND_ON;
636}
637
638static ssize_t state_store(struct kobject *kobj, struct kobj_attribute *attr,
639			   const char *buf, size_t n)
640{
641	suspend_state_t state;
642	int error;
643
644	error = pm_autosleep_lock();
645	if (error)
646		return error;
647
648	if (pm_autosleep_state() > PM_SUSPEND_ON) {
649		error = -EBUSY;
650		goto out;
651	}
652
653	state = decode_state(buf, n);
654	if (state < PM_SUSPEND_MAX) {
655		if (state == PM_SUSPEND_MEM)
656			state = mem_sleep_current;
657
658		error = pm_suspend(state);
659	} else if (state == PM_SUSPEND_MAX) {
660		error = hibernate();
661	} else {
662		error = -EINVAL;
663	}
664
665 out:
666	pm_autosleep_unlock();
667	return error ? error : n;
668}
669
670power_attr(state);
671
672#ifdef CONFIG_PM_SLEEP
673/*
674 * The 'wakeup_count' attribute, along with the functions defined in
675 * drivers/base/power/wakeup.c, provides a means by which wakeup events can be
676 * handled in a non-racy way.
677 *
678 * If a wakeup event occurs when the system is in a sleep state, it simply is
679 * woken up.  In turn, if an event that would wake the system up from a sleep
680 * state occurs when it is undergoing a transition to that sleep state, the
681 * transition should be aborted.  Moreover, if such an event occurs when the
682 * system is in the working state, an attempt to start a transition to the
683 * given sleep state should fail during certain period after the detection of
684 * the event.  Using the 'state' attribute alone is not sufficient to satisfy
685 * these requirements, because a wakeup event may occur exactly when 'state'
686 * is being written to and may be delivered to user space right before it is
687 * frozen, so the event will remain only partially processed until the system is
688 * woken up by another event.  In particular, it won't cause the transition to
689 * a sleep state to be aborted.
690 *
691 * This difficulty may be overcome if user space uses 'wakeup_count' before
692 * writing to 'state'.  It first should read from 'wakeup_count' and store
693 * the read value.  Then, after carrying out its own preparations for the system
694 * transition to a sleep state, it should write the stored value to
695 * 'wakeup_count'.  If that fails, at least one wakeup event has occurred since
696 * 'wakeup_count' was read and 'state' should not be written to.  Otherwise, it
697 * is allowed to write to 'state', but the transition will be aborted if there
698 * are any wakeup events detected after 'wakeup_count' was written to.
699 */
700
701static ssize_t wakeup_count_show(struct kobject *kobj,
702				struct kobj_attribute *attr,
703				char *buf)
704{
705	unsigned int val;
706
707	return pm_get_wakeup_count(&val, true) ?
708		sprintf(buf, "%u\n", val) : -EINTR;
709}
710
711static ssize_t wakeup_count_store(struct kobject *kobj,
712				struct kobj_attribute *attr,
713				const char *buf, size_t n)
714{
715	unsigned int val;
716	int error;
717
718	error = pm_autosleep_lock();
719	if (error)
720		return error;
721
722	if (pm_autosleep_state() > PM_SUSPEND_ON) {
723		error = -EBUSY;
724		goto out;
725	}
726
727	error = -EINVAL;
728	if (sscanf(buf, "%u", &val) == 1) {
729		if (pm_save_wakeup_count(val))
730			error = n;
731		else
732			pm_print_active_wakeup_sources();
733	}
734
735 out:
736	pm_autosleep_unlock();
737	return error;
738}
739
740power_attr(wakeup_count);
741
742#ifdef CONFIG_PM_AUTOSLEEP
743static ssize_t autosleep_show(struct kobject *kobj,
744			      struct kobj_attribute *attr,
745			      char *buf)
746{
747	suspend_state_t state = pm_autosleep_state();
748
749	if (state == PM_SUSPEND_ON)
750		return sprintf(buf, "off\n");
751
752#ifdef CONFIG_SUSPEND
753	if (state < PM_SUSPEND_MAX)
754		return sprintf(buf, "%s\n", pm_states[state] ?
755					pm_states[state] : "error");
756#endif
757#ifdef CONFIG_HIBERNATION
758	return sprintf(buf, "disk\n");
759#else
760	return sprintf(buf, "error");
761#endif
762}
763
764static ssize_t autosleep_store(struct kobject *kobj,
765			       struct kobj_attribute *attr,
766			       const char *buf, size_t n)
767{
768	suspend_state_t state = decode_state(buf, n);
769	int error;
770
771	if (state == PM_SUSPEND_ON
772	    && strcmp(buf, "off") && strcmp(buf, "off\n"))
773		return -EINVAL;
774
775	if (state == PM_SUSPEND_MEM)
776		state = mem_sleep_current;
777
778	error = pm_autosleep_set_state(state);
779	return error ? error : n;
780}
781
782power_attr(autosleep);
783#endif /* CONFIG_PM_AUTOSLEEP */
784
785#ifdef CONFIG_PM_WAKELOCKS
786static ssize_t wake_lock_show(struct kobject *kobj,
787			      struct kobj_attribute *attr,
788			      char *buf)
789{
790	return pm_show_wakelocks(buf, true);
791}
792
793static ssize_t wake_lock_store(struct kobject *kobj,
794			       struct kobj_attribute *attr,
795			       const char *buf, size_t n)
796{
797	int error = pm_wake_lock(buf);
798	return error ? error : n;
799}
800
801power_attr(wake_lock);
802
803static ssize_t wake_unlock_show(struct kobject *kobj,
804				struct kobj_attribute *attr,
805				char *buf)
806{
807	return pm_show_wakelocks(buf, false);
808}
809
810static ssize_t wake_unlock_store(struct kobject *kobj,
811				 struct kobj_attribute *attr,
812				 const char *buf, size_t n)
813{
814	int error = pm_wake_unlock(buf);
815	return error ? error : n;
816}
817
818power_attr(wake_unlock);
819
820#endif /* CONFIG_PM_WAKELOCKS */
821#endif /* CONFIG_PM_SLEEP */
822
823#ifdef CONFIG_PM_TRACE
824int pm_trace_enabled;
825
826static ssize_t pm_trace_show(struct kobject *kobj, struct kobj_attribute *attr,
827			     char *buf)
828{
829	return sprintf(buf, "%d\n", pm_trace_enabled);
830}
831
832static ssize_t
833pm_trace_store(struct kobject *kobj, struct kobj_attribute *attr,
834	       const char *buf, size_t n)
835{
836	int val;
837
838	if (sscanf(buf, "%d", &val) == 1) {
839		pm_trace_enabled = !!val;
840		if (pm_trace_enabled) {
841			pr_warn("PM: Enabling pm_trace changes system date and time during resume.\n"
842				"PM: Correct system time has to be restored manually after resume.\n");
843		}
844		return n;
845	}
846	return -EINVAL;
847}
848
849power_attr(pm_trace);
850
851static ssize_t pm_trace_dev_match_show(struct kobject *kobj,
852				       struct kobj_attribute *attr,
853				       char *buf)
854{
855	return show_trace_dev_match(buf, PAGE_SIZE);
856}
857
858power_attr_ro(pm_trace_dev_match);
859
860#endif /* CONFIG_PM_TRACE */
861
862#ifdef CONFIG_FREEZER
863static ssize_t pm_freeze_timeout_show(struct kobject *kobj,
864				      struct kobj_attribute *attr, char *buf)
865{
866	return sprintf(buf, "%u\n", freeze_timeout_msecs);
867}
868
869static ssize_t pm_freeze_timeout_store(struct kobject *kobj,
870				       struct kobj_attribute *attr,
871				       const char *buf, size_t n)
872{
873	unsigned long val;
874
875	if (kstrtoul(buf, 10, &val))
876		return -EINVAL;
877
878	freeze_timeout_msecs = val;
879	return n;
880}
881
882power_attr(pm_freeze_timeout);
883
884#endif	/* CONFIG_FREEZER*/
885
886static struct attribute * g[] = {
887	&state_attr.attr,
888#ifdef CONFIG_PM_TRACE
889	&pm_trace_attr.attr,
890	&pm_trace_dev_match_attr.attr,
891#endif
892#ifdef CONFIG_PM_SLEEP
893	&pm_async_attr.attr,
894	&wakeup_count_attr.attr,
895#ifdef CONFIG_SUSPEND
896	&mem_sleep_attr.attr,
897	&sync_on_suspend_attr.attr,
898#endif
899#ifdef CONFIG_PM_AUTOSLEEP
900	&autosleep_attr.attr,
901#endif
902#ifdef CONFIG_PM_WAKELOCKS
903	&wake_lock_attr.attr,
904	&wake_unlock_attr.attr,
905#endif
906#ifdef CONFIG_PM_SLEEP_DEBUG
907	&pm_test_attr.attr,
908	&pm_print_times_attr.attr,
909	&pm_wakeup_irq_attr.attr,
910	&pm_debug_messages_attr.attr,
911#endif
912#endif
913#ifdef CONFIG_FREEZER
914	&pm_freeze_timeout_attr.attr,
915#endif
916	NULL,
917};
918
919static const struct attribute_group attr_group = {
920	.attrs = g,
921};
922
923static const struct attribute_group *attr_groups[] = {
924	&attr_group,
925#ifdef CONFIG_PM_SLEEP
926	&suspend_attr_group,
927#endif
928	NULL,
929};
930
931struct workqueue_struct *pm_wq;
932EXPORT_SYMBOL_GPL(pm_wq);
933
934static int __init pm_start_workqueue(void)
935{
936	pm_wq = alloc_workqueue("pm", WQ_FREEZABLE, 0);
937
938	return pm_wq ? 0 : -ENOMEM;
939}
940
941static int __init pm_init(void)
942{
943	int error = pm_start_workqueue();
944	if (error)
945		return error;
946	hibernate_image_size_init();
947	hibernate_reserved_size_init();
948	pm_states_init();
949	power_kobj = kobject_create_and_add("power", NULL);
950	if (!power_kobj)
951		return -ENOMEM;
952	error = sysfs_create_groups(power_kobj, attr_groups);
953	if (error)
954		return error;
955	pm_print_times_init();
956	return pm_autosleep_init();
957}
958
959core_initcall(pm_init);
v4.17
 
  1/*
  2 * kernel/power/main.c - PM subsystem core functionality.
  3 *
  4 * Copyright (c) 2003 Patrick Mochel
  5 * Copyright (c) 2003 Open Source Development Lab
  6 *
  7 * This file is released under the GPLv2
  8 *
  9 */
 10
 11#include <linux/export.h>
 12#include <linux/kobject.h>
 13#include <linux/string.h>
 14#include <linux/pm-trace.h>
 15#include <linux/workqueue.h>
 16#include <linux/debugfs.h>
 17#include <linux/seq_file.h>
 
 
 
 18
 19#include "power.h"
 20
 21DEFINE_MUTEX(pm_mutex);
 22
 23#ifdef CONFIG_PM_SLEEP
 24
 25void lock_system_sleep(void)
 26{
 27	current->flags |= PF_FREEZER_SKIP;
 28	mutex_lock(&pm_mutex);
 29}
 30EXPORT_SYMBOL_GPL(lock_system_sleep);
 31
 32void unlock_system_sleep(void)
 33{
 34	/*
 35	 * Don't use freezer_count() because we don't want the call to
 36	 * try_to_freeze() here.
 37	 *
 38	 * Reason:
 39	 * Fundamentally, we just don't need it, because freezing condition
 40	 * doesn't come into effect until we release the pm_mutex lock,
 41	 * since the freezer always works with pm_mutex held.
 
 42	 *
 43	 * More importantly, in the case of hibernation,
 44	 * unlock_system_sleep() gets called in snapshot_read() and
 45	 * snapshot_write() when the freezing condition is still in effect.
 46	 * Which means, if we use try_to_freeze() here, it would make them
 47	 * enter the refrigerator, thus causing hibernation to lockup.
 48	 */
 49	current->flags &= ~PF_FREEZER_SKIP;
 50	mutex_unlock(&pm_mutex);
 51}
 52EXPORT_SYMBOL_GPL(unlock_system_sleep);
 53
 
 
 
 
 
 
 
 
 
 
 
 
 
 54/* Routines for PM-transition notifications */
 55
 56static BLOCKING_NOTIFIER_HEAD(pm_chain_head);
 57
 58int register_pm_notifier(struct notifier_block *nb)
 59{
 60	return blocking_notifier_chain_register(&pm_chain_head, nb);
 61}
 62EXPORT_SYMBOL_GPL(register_pm_notifier);
 63
 64int unregister_pm_notifier(struct notifier_block *nb)
 65{
 66	return blocking_notifier_chain_unregister(&pm_chain_head, nb);
 67}
 68EXPORT_SYMBOL_GPL(unregister_pm_notifier);
 69
 70int __pm_notifier_call_chain(unsigned long val, int nr_to_call, int *nr_calls)
 71{
 72	int ret;
 73
 74	ret = __blocking_notifier_call_chain(&pm_chain_head, val, NULL,
 75						nr_to_call, nr_calls);
 76
 77	return notifier_to_errno(ret);
 78}
 79int pm_notifier_call_chain(unsigned long val)
 80{
 81	return __pm_notifier_call_chain(val, -1, NULL);
 82}
 83
 84/* If set, devices may be suspended and resumed asynchronously. */
 85int pm_async_enabled = 1;
 86
 87static ssize_t pm_async_show(struct kobject *kobj, struct kobj_attribute *attr,
 88			     char *buf)
 89{
 90	return sprintf(buf, "%d\n", pm_async_enabled);
 91}
 92
 93static ssize_t pm_async_store(struct kobject *kobj, struct kobj_attribute *attr,
 94			      const char *buf, size_t n)
 95{
 96	unsigned long val;
 97
 98	if (kstrtoul(buf, 10, &val))
 99		return -EINVAL;
100
101	if (val > 1)
102		return -EINVAL;
103
104	pm_async_enabled = val;
105	return n;
106}
107
108power_attr(pm_async);
109
110#ifdef CONFIG_SUSPEND
111static ssize_t mem_sleep_show(struct kobject *kobj, struct kobj_attribute *attr,
112			      char *buf)
113{
114	char *s = buf;
115	suspend_state_t i;
116
117	for (i = PM_SUSPEND_MIN; i < PM_SUSPEND_MAX; i++)
118		if (mem_sleep_states[i]) {
119			const char *label = mem_sleep_states[i];
120
121			if (mem_sleep_current == i)
122				s += sprintf(s, "[%s] ", label);
123			else
124				s += sprintf(s, "%s ", label);
125		}
126
127	/* Convert the last space to a newline if needed. */
128	if (s != buf)
129		*(s-1) = '\n';
130
131	return (s - buf);
132}
133
134static suspend_state_t decode_suspend_state(const char *buf, size_t n)
135{
136	suspend_state_t state;
137	char *p;
138	int len;
139
140	p = memchr(buf, '\n', n);
141	len = p ? p - buf : n;
142
143	for (state = PM_SUSPEND_MIN; state < PM_SUSPEND_MAX; state++) {
144		const char *label = mem_sleep_states[state];
145
146		if (label && len == strlen(label) && !strncmp(buf, label, len))
147			return state;
148	}
149
150	return PM_SUSPEND_ON;
151}
152
153static ssize_t mem_sleep_store(struct kobject *kobj, struct kobj_attribute *attr,
154			       const char *buf, size_t n)
155{
156	suspend_state_t state;
157	int error;
158
159	error = pm_autosleep_lock();
160	if (error)
161		return error;
162
163	if (pm_autosleep_state() > PM_SUSPEND_ON) {
164		error = -EBUSY;
165		goto out;
166	}
167
168	state = decode_suspend_state(buf, n);
169	if (state < PM_SUSPEND_MAX && state > PM_SUSPEND_ON)
170		mem_sleep_current = state;
171	else
172		error = -EINVAL;
173
174 out:
175	pm_autosleep_unlock();
176	return error ? error : n;
177}
178
179power_attr(mem_sleep);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
180#endif /* CONFIG_SUSPEND */
181
182#ifdef CONFIG_PM_SLEEP_DEBUG
183int pm_test_level = TEST_NONE;
184
185static const char * const pm_tests[__TEST_AFTER_LAST] = {
186	[TEST_NONE] = "none",
187	[TEST_CORE] = "core",
188	[TEST_CPUS] = "processors",
189	[TEST_PLATFORM] = "platform",
190	[TEST_DEVICES] = "devices",
191	[TEST_FREEZER] = "freezer",
192};
193
194static ssize_t pm_test_show(struct kobject *kobj, struct kobj_attribute *attr,
195				char *buf)
196{
197	char *s = buf;
198	int level;
199
200	for (level = TEST_FIRST; level <= TEST_MAX; level++)
201		if (pm_tests[level]) {
202			if (level == pm_test_level)
203				s += sprintf(s, "[%s] ", pm_tests[level]);
204			else
205				s += sprintf(s, "%s ", pm_tests[level]);
206		}
207
208	if (s != buf)
209		/* convert the last space to a newline */
210		*(s-1) = '\n';
211
212	return (s - buf);
213}
214
215static ssize_t pm_test_store(struct kobject *kobj, struct kobj_attribute *attr,
216				const char *buf, size_t n)
217{
218	const char * const *s;
219	int level;
220	char *p;
221	int len;
222	int error = -EINVAL;
223
224	p = memchr(buf, '\n', n);
225	len = p ? p - buf : n;
226
227	lock_system_sleep();
228
229	level = TEST_FIRST;
230	for (s = &pm_tests[level]; level <= TEST_MAX; s++, level++)
231		if (*s && len == strlen(*s) && !strncmp(buf, *s, len)) {
232			pm_test_level = level;
233			error = 0;
234			break;
235		}
236
237	unlock_system_sleep();
238
239	return error ? error : n;
240}
241
242power_attr(pm_test);
243#endif /* CONFIG_PM_SLEEP_DEBUG */
244
245#ifdef CONFIG_DEBUG_FS
246static char *suspend_step_name(enum suspend_stat_step step)
247{
248	switch (step) {
249	case SUSPEND_FREEZE:
250		return "freeze";
251	case SUSPEND_PREPARE:
252		return "prepare";
253	case SUSPEND_SUSPEND:
254		return "suspend";
255	case SUSPEND_SUSPEND_NOIRQ:
256		return "suspend_noirq";
257	case SUSPEND_RESUME_NOIRQ:
258		return "resume_noirq";
259	case SUSPEND_RESUME:
260		return "resume";
261	default:
262		return "";
263	}
264}
265
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
266static int suspend_stats_show(struct seq_file *s, void *unused)
267{
268	int i, index, last_dev, last_errno, last_step;
269
270	last_dev = suspend_stats.last_failed_dev + REC_FAILED_NUM - 1;
271	last_dev %= REC_FAILED_NUM;
272	last_errno = suspend_stats.last_failed_errno + REC_FAILED_NUM - 1;
273	last_errno %= REC_FAILED_NUM;
274	last_step = suspend_stats.last_failed_step + REC_FAILED_NUM - 1;
275	last_step %= REC_FAILED_NUM;
276	seq_printf(s, "%s: %d\n%s: %d\n%s: %d\n%s: %d\n%s: %d\n"
277			"%s: %d\n%s: %d\n%s: %d\n%s: %d\n%s: %d\n",
278			"success", suspend_stats.success,
279			"fail", suspend_stats.fail,
280			"failed_freeze", suspend_stats.failed_freeze,
281			"failed_prepare", suspend_stats.failed_prepare,
282			"failed_suspend", suspend_stats.failed_suspend,
283			"failed_suspend_late",
284				suspend_stats.failed_suspend_late,
285			"failed_suspend_noirq",
286				suspend_stats.failed_suspend_noirq,
287			"failed_resume", suspend_stats.failed_resume,
288			"failed_resume_early",
289				suspend_stats.failed_resume_early,
290			"failed_resume_noirq",
291				suspend_stats.failed_resume_noirq);
292	seq_printf(s,	"failures:\n  last_failed_dev:\t%-s\n",
293			suspend_stats.failed_devs[last_dev]);
294	for (i = 1; i < REC_FAILED_NUM; i++) {
295		index = last_dev + REC_FAILED_NUM - i;
296		index %= REC_FAILED_NUM;
297		seq_printf(s, "\t\t\t%-s\n",
298			suspend_stats.failed_devs[index]);
299	}
300	seq_printf(s,	"  last_failed_errno:\t%-d\n",
301			suspend_stats.errno[last_errno]);
302	for (i = 1; i < REC_FAILED_NUM; i++) {
303		index = last_errno + REC_FAILED_NUM - i;
304		index %= REC_FAILED_NUM;
305		seq_printf(s, "\t\t\t%-d\n",
306			suspend_stats.errno[index]);
307	}
308	seq_printf(s,	"  last_failed_step:\t%-s\n",
309			suspend_step_name(
310				suspend_stats.failed_steps[last_step]));
311	for (i = 1; i < REC_FAILED_NUM; i++) {
312		index = last_step + REC_FAILED_NUM - i;
313		index %= REC_FAILED_NUM;
314		seq_printf(s, "\t\t\t%-s\n",
315			suspend_step_name(
316				suspend_stats.failed_steps[index]));
317	}
318
319	return 0;
320}
321
322static int suspend_stats_open(struct inode *inode, struct file *file)
323{
324	return single_open(file, suspend_stats_show, NULL);
325}
326
327static const struct file_operations suspend_stats_operations = {
328	.open           = suspend_stats_open,
329	.read           = seq_read,
330	.llseek         = seq_lseek,
331	.release        = single_release,
332};
333
334static int __init pm_debugfs_init(void)
335{
336	debugfs_create_file("suspend_stats", S_IFREG | S_IRUGO,
337			NULL, NULL, &suspend_stats_operations);
338	return 0;
339}
340
341late_initcall(pm_debugfs_init);
342#endif /* CONFIG_DEBUG_FS */
343
344#endif /* CONFIG_PM_SLEEP */
345
346#ifdef CONFIG_PM_SLEEP_DEBUG
347/*
348 * pm_print_times: print time taken by devices to suspend and resume.
349 *
350 * show() returns whether printing of suspend and resume times is enabled.
351 * store() accepts 0 or 1.  0 disables printing and 1 enables it.
352 */
353bool pm_print_times_enabled;
354
355static ssize_t pm_print_times_show(struct kobject *kobj,
356				   struct kobj_attribute *attr, char *buf)
357{
358	return sprintf(buf, "%d\n", pm_print_times_enabled);
359}
360
361static ssize_t pm_print_times_store(struct kobject *kobj,
362				    struct kobj_attribute *attr,
363				    const char *buf, size_t n)
364{
365	unsigned long val;
366
367	if (kstrtoul(buf, 10, &val))
368		return -EINVAL;
369
370	if (val > 1)
371		return -EINVAL;
372
373	pm_print_times_enabled = !!val;
374	return n;
375}
376
377power_attr(pm_print_times);
378
379static inline void pm_print_times_init(void)
380{
381	pm_print_times_enabled = !!initcall_debug;
382}
383
384static ssize_t pm_wakeup_irq_show(struct kobject *kobj,
385					struct kobj_attribute *attr,
386					char *buf)
387{
388	return pm_wakeup_irq ? sprintf(buf, "%u\n", pm_wakeup_irq) : -ENODATA;
389}
390
391power_attr_ro(pm_wakeup_irq);
392
393bool pm_debug_messages_on __read_mostly;
394
395static ssize_t pm_debug_messages_show(struct kobject *kobj,
396				      struct kobj_attribute *attr, char *buf)
397{
398	return sprintf(buf, "%d\n", pm_debug_messages_on);
399}
400
401static ssize_t pm_debug_messages_store(struct kobject *kobj,
402				       struct kobj_attribute *attr,
403				       const char *buf, size_t n)
404{
405	unsigned long val;
406
407	if (kstrtoul(buf, 10, &val))
408		return -EINVAL;
409
410	if (val > 1)
411		return -EINVAL;
412
413	pm_debug_messages_on = !!val;
414	return n;
415}
416
417power_attr(pm_debug_messages);
418
 
 
 
 
 
 
 
419/**
420 * __pm_pr_dbg - Print a suspend debug message to the kernel log.
421 * @defer: Whether or not to use printk_deferred() to print the message.
422 * @fmt: Message format.
423 *
424 * The message will be emitted if enabled through the pm_debug_messages
425 * sysfs attribute.
426 */
427void __pm_pr_dbg(bool defer, const char *fmt, ...)
428{
429	struct va_format vaf;
430	va_list args;
431
432	if (!pm_debug_messages_on)
433		return;
434
435	va_start(args, fmt);
436
437	vaf.fmt = fmt;
438	vaf.va = &args;
439
440	if (defer)
441		printk_deferred(KERN_DEBUG "PM: %pV", &vaf);
442	else
443		printk(KERN_DEBUG "PM: %pV", &vaf);
444
445	va_end(args);
446}
447
448#else /* !CONFIG_PM_SLEEP_DEBUG */
449static inline void pm_print_times_init(void) {}
450#endif /* CONFIG_PM_SLEEP_DEBUG */
451
452struct kobject *power_kobj;
453
454/**
455 * state - control system sleep states.
456 *
457 * show() returns available sleep state labels, which may be "mem", "standby",
458 * "freeze" and "disk" (hibernation).  See Documentation/power/states.txt for a
459 * description of what they mean.
 
460 *
461 * store() accepts one of those strings, translates it into the proper
462 * enumerated value, and initiates a suspend transition.
463 */
464static ssize_t state_show(struct kobject *kobj, struct kobj_attribute *attr,
465			  char *buf)
466{
467	char *s = buf;
468#ifdef CONFIG_SUSPEND
469	suspend_state_t i;
470
471	for (i = PM_SUSPEND_MIN; i < PM_SUSPEND_MAX; i++)
472		if (pm_states[i])
473			s += sprintf(s,"%s ", pm_states[i]);
474
475#endif
476	if (hibernation_available())
477		s += sprintf(s, "disk ");
478	if (s != buf)
479		/* convert the last space to a newline */
480		*(s-1) = '\n';
481	return (s - buf);
482}
483
484static suspend_state_t decode_state(const char *buf, size_t n)
485{
486#ifdef CONFIG_SUSPEND
487	suspend_state_t state;
488#endif
489	char *p;
490	int len;
491
492	p = memchr(buf, '\n', n);
493	len = p ? p - buf : n;
494
495	/* Check hibernation first. */
496	if (len == 4 && !strncmp(buf, "disk", len))
497		return PM_SUSPEND_MAX;
498
499#ifdef CONFIG_SUSPEND
500	for (state = PM_SUSPEND_MIN; state < PM_SUSPEND_MAX; state++) {
501		const char *label = pm_states[state];
502
503		if (label && len == strlen(label) && !strncmp(buf, label, len))
504			return state;
505	}
506#endif
507
508	return PM_SUSPEND_ON;
509}
510
511static ssize_t state_store(struct kobject *kobj, struct kobj_attribute *attr,
512			   const char *buf, size_t n)
513{
514	suspend_state_t state;
515	int error;
516
517	error = pm_autosleep_lock();
518	if (error)
519		return error;
520
521	if (pm_autosleep_state() > PM_SUSPEND_ON) {
522		error = -EBUSY;
523		goto out;
524	}
525
526	state = decode_state(buf, n);
527	if (state < PM_SUSPEND_MAX) {
528		if (state == PM_SUSPEND_MEM)
529			state = mem_sleep_current;
530
531		error = pm_suspend(state);
532	} else if (state == PM_SUSPEND_MAX) {
533		error = hibernate();
534	} else {
535		error = -EINVAL;
536	}
537
538 out:
539	pm_autosleep_unlock();
540	return error ? error : n;
541}
542
543power_attr(state);
544
545#ifdef CONFIG_PM_SLEEP
546/*
547 * The 'wakeup_count' attribute, along with the functions defined in
548 * drivers/base/power/wakeup.c, provides a means by which wakeup events can be
549 * handled in a non-racy way.
550 *
551 * If a wakeup event occurs when the system is in a sleep state, it simply is
552 * woken up.  In turn, if an event that would wake the system up from a sleep
553 * state occurs when it is undergoing a transition to that sleep state, the
554 * transition should be aborted.  Moreover, if such an event occurs when the
555 * system is in the working state, an attempt to start a transition to the
556 * given sleep state should fail during certain period after the detection of
557 * the event.  Using the 'state' attribute alone is not sufficient to satisfy
558 * these requirements, because a wakeup event may occur exactly when 'state'
559 * is being written to and may be delivered to user space right before it is
560 * frozen, so the event will remain only partially processed until the system is
561 * woken up by another event.  In particular, it won't cause the transition to
562 * a sleep state to be aborted.
563 *
564 * This difficulty may be overcome if user space uses 'wakeup_count' before
565 * writing to 'state'.  It first should read from 'wakeup_count' and store
566 * the read value.  Then, after carrying out its own preparations for the system
567 * transition to a sleep state, it should write the stored value to
568 * 'wakeup_count'.  If that fails, at least one wakeup event has occurred since
569 * 'wakeup_count' was read and 'state' should not be written to.  Otherwise, it
570 * is allowed to write to 'state', but the transition will be aborted if there
571 * are any wakeup events detected after 'wakeup_count' was written to.
572 */
573
574static ssize_t wakeup_count_show(struct kobject *kobj,
575				struct kobj_attribute *attr,
576				char *buf)
577{
578	unsigned int val;
579
580	return pm_get_wakeup_count(&val, true) ?
581		sprintf(buf, "%u\n", val) : -EINTR;
582}
583
584static ssize_t wakeup_count_store(struct kobject *kobj,
585				struct kobj_attribute *attr,
586				const char *buf, size_t n)
587{
588	unsigned int val;
589	int error;
590
591	error = pm_autosleep_lock();
592	if (error)
593		return error;
594
595	if (pm_autosleep_state() > PM_SUSPEND_ON) {
596		error = -EBUSY;
597		goto out;
598	}
599
600	error = -EINVAL;
601	if (sscanf(buf, "%u", &val) == 1) {
602		if (pm_save_wakeup_count(val))
603			error = n;
604		else
605			pm_print_active_wakeup_sources();
606	}
607
608 out:
609	pm_autosleep_unlock();
610	return error;
611}
612
613power_attr(wakeup_count);
614
615#ifdef CONFIG_PM_AUTOSLEEP
616static ssize_t autosleep_show(struct kobject *kobj,
617			      struct kobj_attribute *attr,
618			      char *buf)
619{
620	suspend_state_t state = pm_autosleep_state();
621
622	if (state == PM_SUSPEND_ON)
623		return sprintf(buf, "off\n");
624
625#ifdef CONFIG_SUSPEND
626	if (state < PM_SUSPEND_MAX)
627		return sprintf(buf, "%s\n", pm_states[state] ?
628					pm_states[state] : "error");
629#endif
630#ifdef CONFIG_HIBERNATION
631	return sprintf(buf, "disk\n");
632#else
633	return sprintf(buf, "error");
634#endif
635}
636
637static ssize_t autosleep_store(struct kobject *kobj,
638			       struct kobj_attribute *attr,
639			       const char *buf, size_t n)
640{
641	suspend_state_t state = decode_state(buf, n);
642	int error;
643
644	if (state == PM_SUSPEND_ON
645	    && strcmp(buf, "off") && strcmp(buf, "off\n"))
646		return -EINVAL;
647
648	if (state == PM_SUSPEND_MEM)
649		state = mem_sleep_current;
650
651	error = pm_autosleep_set_state(state);
652	return error ? error : n;
653}
654
655power_attr(autosleep);
656#endif /* CONFIG_PM_AUTOSLEEP */
657
658#ifdef CONFIG_PM_WAKELOCKS
659static ssize_t wake_lock_show(struct kobject *kobj,
660			      struct kobj_attribute *attr,
661			      char *buf)
662{
663	return pm_show_wakelocks(buf, true);
664}
665
666static ssize_t wake_lock_store(struct kobject *kobj,
667			       struct kobj_attribute *attr,
668			       const char *buf, size_t n)
669{
670	int error = pm_wake_lock(buf);
671	return error ? error : n;
672}
673
674power_attr(wake_lock);
675
676static ssize_t wake_unlock_show(struct kobject *kobj,
677				struct kobj_attribute *attr,
678				char *buf)
679{
680	return pm_show_wakelocks(buf, false);
681}
682
683static ssize_t wake_unlock_store(struct kobject *kobj,
684				 struct kobj_attribute *attr,
685				 const char *buf, size_t n)
686{
687	int error = pm_wake_unlock(buf);
688	return error ? error : n;
689}
690
691power_attr(wake_unlock);
692
693#endif /* CONFIG_PM_WAKELOCKS */
694#endif /* CONFIG_PM_SLEEP */
695
696#ifdef CONFIG_PM_TRACE
697int pm_trace_enabled;
698
699static ssize_t pm_trace_show(struct kobject *kobj, struct kobj_attribute *attr,
700			     char *buf)
701{
702	return sprintf(buf, "%d\n", pm_trace_enabled);
703}
704
705static ssize_t
706pm_trace_store(struct kobject *kobj, struct kobj_attribute *attr,
707	       const char *buf, size_t n)
708{
709	int val;
710
711	if (sscanf(buf, "%d", &val) == 1) {
712		pm_trace_enabled = !!val;
713		if (pm_trace_enabled) {
714			pr_warn("PM: Enabling pm_trace changes system date and time during resume.\n"
715				"PM: Correct system time has to be restored manually after resume.\n");
716		}
717		return n;
718	}
719	return -EINVAL;
720}
721
722power_attr(pm_trace);
723
724static ssize_t pm_trace_dev_match_show(struct kobject *kobj,
725				       struct kobj_attribute *attr,
726				       char *buf)
727{
728	return show_trace_dev_match(buf, PAGE_SIZE);
729}
730
731power_attr_ro(pm_trace_dev_match);
732
733#endif /* CONFIG_PM_TRACE */
734
735#ifdef CONFIG_FREEZER
736static ssize_t pm_freeze_timeout_show(struct kobject *kobj,
737				      struct kobj_attribute *attr, char *buf)
738{
739	return sprintf(buf, "%u\n", freeze_timeout_msecs);
740}
741
742static ssize_t pm_freeze_timeout_store(struct kobject *kobj,
743				       struct kobj_attribute *attr,
744				       const char *buf, size_t n)
745{
746	unsigned long val;
747
748	if (kstrtoul(buf, 10, &val))
749		return -EINVAL;
750
751	freeze_timeout_msecs = val;
752	return n;
753}
754
755power_attr(pm_freeze_timeout);
756
757#endif	/* CONFIG_FREEZER*/
758
759static struct attribute * g[] = {
760	&state_attr.attr,
761#ifdef CONFIG_PM_TRACE
762	&pm_trace_attr.attr,
763	&pm_trace_dev_match_attr.attr,
764#endif
765#ifdef CONFIG_PM_SLEEP
766	&pm_async_attr.attr,
767	&wakeup_count_attr.attr,
768#ifdef CONFIG_SUSPEND
769	&mem_sleep_attr.attr,
 
770#endif
771#ifdef CONFIG_PM_AUTOSLEEP
772	&autosleep_attr.attr,
773#endif
774#ifdef CONFIG_PM_WAKELOCKS
775	&wake_lock_attr.attr,
776	&wake_unlock_attr.attr,
777#endif
778#ifdef CONFIG_PM_SLEEP_DEBUG
779	&pm_test_attr.attr,
780	&pm_print_times_attr.attr,
781	&pm_wakeup_irq_attr.attr,
782	&pm_debug_messages_attr.attr,
783#endif
784#endif
785#ifdef CONFIG_FREEZER
786	&pm_freeze_timeout_attr.attr,
787#endif
788	NULL,
789};
790
791static const struct attribute_group attr_group = {
792	.attrs = g,
793};
794
 
 
 
 
 
 
 
 
795struct workqueue_struct *pm_wq;
796EXPORT_SYMBOL_GPL(pm_wq);
797
798static int __init pm_start_workqueue(void)
799{
800	pm_wq = alloc_workqueue("pm", WQ_FREEZABLE, 0);
801
802	return pm_wq ? 0 : -ENOMEM;
803}
804
805static int __init pm_init(void)
806{
807	int error = pm_start_workqueue();
808	if (error)
809		return error;
810	hibernate_image_size_init();
811	hibernate_reserved_size_init();
812	pm_states_init();
813	power_kobj = kobject_create_and_add("power", NULL);
814	if (!power_kobj)
815		return -ENOMEM;
816	error = sysfs_create_group(power_kobj, &attr_group);
817	if (error)
818		return error;
819	pm_print_times_init();
820	return pm_autosleep_init();
821}
822
823core_initcall(pm_init);