2 * kernel/power/main.c - PM subsystem core functionality.
4 * Copyright (c) 2003 Patrick Mochel
5 * Copyright (c) 2003 Open Source Development Lab
7 * This file is released under the GPLv2
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 #include <linux/suspend.h>
22 #ifdef CONFIG_PM_SLEEP
24 void lock_system_sleep(void)
26 current->flags |= PF_FREEZER_SKIP;
27 mutex_lock(&system_transition_mutex);
29 EXPORT_SYMBOL_GPL(lock_system_sleep);
31 void unlock_system_sleep(void)
34 * Don't use freezer_count() because we don't want the call to
35 * try_to_freeze() here.
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.
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.
49 current->flags &= ~PF_FREEZER_SKIP;
50 mutex_unlock(&system_transition_mutex);
52 EXPORT_SYMBOL_GPL(unlock_system_sleep);
54 /* Routines for PM-transition notifications */
56 static BLOCKING_NOTIFIER_HEAD(pm_chain_head);
58 int register_pm_notifier(struct notifier_block *nb)
60 return blocking_notifier_chain_register(&pm_chain_head, nb);
62 EXPORT_SYMBOL_GPL(register_pm_notifier);
64 int unregister_pm_notifier(struct notifier_block *nb)
66 return blocking_notifier_chain_unregister(&pm_chain_head, nb);
68 EXPORT_SYMBOL_GPL(unregister_pm_notifier);
70 int __pm_notifier_call_chain(unsigned long val, int nr_to_call, int *nr_calls)
74 ret = __blocking_notifier_call_chain(&pm_chain_head, val, NULL,
75 nr_to_call, nr_calls);
77 return notifier_to_errno(ret);
79 int pm_notifier_call_chain(unsigned long val)
81 return __pm_notifier_call_chain(val, -1, NULL);
84 /* If set, devices may be suspended and resumed asynchronously. */
85 int pm_async_enabled = 1;
87 static ssize_t pm_async_show(struct kobject *kobj, struct kobj_attribute *attr,
90 return sprintf(buf, "%d\n", pm_async_enabled);
93 static ssize_t pm_async_store(struct kobject *kobj, struct kobj_attribute *attr,
94 const char *buf, size_t n)
98 if (kstrtoul(buf, 10, &val))
104 pm_async_enabled = val;
108 power_attr(pm_async);
110 #ifdef CONFIG_SUSPEND
111 static ssize_t mem_sleep_show(struct kobject *kobj, struct kobj_attribute *attr,
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];
121 if (mem_sleep_current == i)
122 s += sprintf(s, "[%s] ", label);
124 s += sprintf(s, "%s ", label);
127 /* Convert the last space to a newline if needed. */
134 static suspend_state_t decode_suspend_state(const char *buf, size_t n)
136 suspend_state_t state;
140 p = memchr(buf, '\n', n);
141 len = p ? p - buf : n;
143 for (state = PM_SUSPEND_MIN; state < PM_SUSPEND_MAX; state++) {
144 const char *label = mem_sleep_states[state];
146 if (label && len == strlen(label) && !strncmp(buf, label, len))
150 return PM_SUSPEND_ON;
153 static ssize_t mem_sleep_store(struct kobject *kobj, struct kobj_attribute *attr,
154 const char *buf, size_t n)
156 suspend_state_t state;
159 error = pm_autosleep_lock();
163 if (pm_autosleep_state() > PM_SUSPEND_ON) {
168 state = decode_suspend_state(buf, n);
169 if (state < PM_SUSPEND_MAX && state > PM_SUSPEND_ON)
170 mem_sleep_current = state;
175 pm_autosleep_unlock();
176 return error ? error : n;
179 power_attr(mem_sleep);
180 #endif /* CONFIG_SUSPEND */
182 #ifdef CONFIG_PM_SLEEP_DEBUG
183 int pm_test_level = TEST_NONE;
185 static 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",
194 static ssize_t pm_test_show(struct kobject *kobj, struct kobj_attribute *attr,
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]);
205 s += sprintf(s, "%s ", pm_tests[level]);
209 /* convert the last space to a newline */
215 static ssize_t pm_test_store(struct kobject *kobj, struct kobj_attribute *attr,
216 const char *buf, size_t n)
218 const char * const *s;
224 p = memchr(buf, '\n', n);
225 len = p ? p - buf : n;
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;
237 unlock_system_sleep();
239 return error ? error : n;
243 #endif /* CONFIG_PM_SLEEP_DEBUG */
245 #ifdef CONFIG_DEBUG_FS
246 static char *suspend_step_name(enum suspend_stat_step step)
251 case SUSPEND_PREPARE:
253 case SUSPEND_SUSPEND:
255 case SUSPEND_SUSPEND_NOIRQ:
256 return "suspend_noirq";
257 case SUSPEND_RESUME_NOIRQ:
258 return "resume_noirq";
266 static int suspend_stats_show(struct seq_file *s, void *unused)
268 int i, index, last_dev, last_errno, last_step;
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]);
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]);
308 seq_printf(s, " last_failed_step:\t%-s\n",
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",
316 suspend_stats.failed_steps[index]));
321 DEFINE_SHOW_ATTRIBUTE(suspend_stats);
323 static int __init pm_debugfs_init(void)
325 debugfs_create_file("suspend_stats", S_IFREG | S_IRUGO,
326 NULL, NULL, &suspend_stats_fops);
330 late_initcall(pm_debugfs_init);
331 #endif /* CONFIG_DEBUG_FS */
333 #endif /* CONFIG_PM_SLEEP */
335 #ifdef CONFIG_PM_SLEEP_DEBUG
337 * pm_print_times: print time taken by devices to suspend and resume.
339 * show() returns whether printing of suspend and resume times is enabled.
340 * store() accepts 0 or 1. 0 disables printing and 1 enables it.
342 bool pm_print_times_enabled;
344 static ssize_t pm_print_times_show(struct kobject *kobj,
345 struct kobj_attribute *attr, char *buf)
347 return sprintf(buf, "%d\n", pm_print_times_enabled);
350 static ssize_t pm_print_times_store(struct kobject *kobj,
351 struct kobj_attribute *attr,
352 const char *buf, size_t n)
356 if (kstrtoul(buf, 10, &val))
362 pm_print_times_enabled = !!val;
366 power_attr(pm_print_times);
368 static inline void pm_print_times_init(void)
370 pm_print_times_enabled = !!initcall_debug;
373 static ssize_t pm_wakeup_irq_show(struct kobject *kobj,
374 struct kobj_attribute *attr,
377 return pm_wakeup_irq ? sprintf(buf, "%u\n", pm_wakeup_irq) : -ENODATA;
380 power_attr_ro(pm_wakeup_irq);
382 bool pm_debug_messages_on __read_mostly;
384 static ssize_t pm_debug_messages_show(struct kobject *kobj,
385 struct kobj_attribute *attr, char *buf)
387 return sprintf(buf, "%d\n", pm_debug_messages_on);
390 static ssize_t pm_debug_messages_store(struct kobject *kobj,
391 struct kobj_attribute *attr,
392 const char *buf, size_t n)
396 if (kstrtoul(buf, 10, &val))
402 pm_debug_messages_on = !!val;
406 power_attr(pm_debug_messages);
409 * __pm_pr_dbg - Print a suspend debug message to the kernel log.
410 * @defer: Whether or not to use printk_deferred() to print the message.
411 * @fmt: Message format.
413 * The message will be emitted if enabled through the pm_debug_messages
416 void __pm_pr_dbg(bool defer, const char *fmt, ...)
418 struct va_format vaf;
421 if (!pm_debug_messages_on)
430 printk_deferred(KERN_DEBUG "PM: %pV", &vaf);
432 printk(KERN_DEBUG "PM: %pV", &vaf);
437 #else /* !CONFIG_PM_SLEEP_DEBUG */
438 static inline void pm_print_times_init(void) {}
439 #endif /* CONFIG_PM_SLEEP_DEBUG */
441 struct kobject *power_kobj;
444 * state - control system sleep states.
446 * show() returns available sleep state labels, which may be "mem", "standby",
447 * "freeze" and "disk" (hibernation).
448 * See Documentation/admin-guide/pm/sleep-states.rst for a description of
451 * store() accepts one of those strings, translates it into the proper
452 * enumerated value, and initiates a suspend transition.
454 static ssize_t state_show(struct kobject *kobj, struct kobj_attribute *attr,
458 #ifdef CONFIG_SUSPEND
461 for (i = PM_SUSPEND_MIN; i < PM_SUSPEND_MAX; i++)
463 s += sprintf(s,"%s ", pm_states[i]);
466 if (hibernation_available())
467 s += sprintf(s, "disk ");
469 /* convert the last space to a newline */
474 static suspend_state_t decode_state(const char *buf, size_t n)
476 #ifdef CONFIG_SUSPEND
477 suspend_state_t state;
482 p = memchr(buf, '\n', n);
483 len = p ? p - buf : n;
485 /* Check hibernation first. */
486 if (len == 4 && !strncmp(buf, "disk", len))
487 return PM_SUSPEND_MAX;
489 #ifdef CONFIG_SUSPEND
490 for (state = PM_SUSPEND_MIN; state < PM_SUSPEND_MAX; state++) {
491 const char *label = pm_states[state];
493 if (label && len == strlen(label) && !strncmp(buf, label, len))
498 return PM_SUSPEND_ON;
501 static ssize_t state_store(struct kobject *kobj, struct kobj_attribute *attr,
502 const char *buf, size_t n)
504 suspend_state_t state;
507 error = pm_autosleep_lock();
511 if (pm_autosleep_state() > PM_SUSPEND_ON) {
516 state = decode_state(buf, n);
517 if (state < PM_SUSPEND_MAX) {
518 if (state == PM_SUSPEND_MEM)
519 state = mem_sleep_current;
521 error = pm_suspend(state);
522 } else if (state == PM_SUSPEND_MAX) {
529 pm_autosleep_unlock();
530 return error ? error : n;
535 #ifdef CONFIG_PM_SLEEP
537 * The 'wakeup_count' attribute, along with the functions defined in
538 * drivers/base/power/wakeup.c, provides a means by which wakeup events can be
539 * handled in a non-racy way.
541 * If a wakeup event occurs when the system is in a sleep state, it simply is
542 * woken up. In turn, if an event that would wake the system up from a sleep
543 * state occurs when it is undergoing a transition to that sleep state, the
544 * transition should be aborted. Moreover, if such an event occurs when the
545 * system is in the working state, an attempt to start a transition to the
546 * given sleep state should fail during certain period after the detection of
547 * the event. Using the 'state' attribute alone is not sufficient to satisfy
548 * these requirements, because a wakeup event may occur exactly when 'state'
549 * is being written to and may be delivered to user space right before it is
550 * frozen, so the event will remain only partially processed until the system is
551 * woken up by another event. In particular, it won't cause the transition to
552 * a sleep state to be aborted.
554 * This difficulty may be overcome if user space uses 'wakeup_count' before
555 * writing to 'state'. It first should read from 'wakeup_count' and store
556 * the read value. Then, after carrying out its own preparations for the system
557 * transition to a sleep state, it should write the stored value to
558 * 'wakeup_count'. If that fails, at least one wakeup event has occurred since
559 * 'wakeup_count' was read and 'state' should not be written to. Otherwise, it
560 * is allowed to write to 'state', but the transition will be aborted if there
561 * are any wakeup events detected after 'wakeup_count' was written to.
564 static ssize_t wakeup_count_show(struct kobject *kobj,
565 struct kobj_attribute *attr,
570 return pm_get_wakeup_count(&val, true) ?
571 sprintf(buf, "%u\n", val) : -EINTR;
574 static ssize_t wakeup_count_store(struct kobject *kobj,
575 struct kobj_attribute *attr,
576 const char *buf, size_t n)
581 error = pm_autosleep_lock();
585 if (pm_autosleep_state() > PM_SUSPEND_ON) {
591 if (sscanf(buf, "%u", &val) == 1) {
592 if (pm_save_wakeup_count(val))
595 pm_print_active_wakeup_sources();
599 pm_autosleep_unlock();
603 power_attr(wakeup_count);
605 #ifdef CONFIG_PM_AUTOSLEEP
606 static ssize_t autosleep_show(struct kobject *kobj,
607 struct kobj_attribute *attr,
610 suspend_state_t state = pm_autosleep_state();
612 if (state == PM_SUSPEND_ON)
613 return sprintf(buf, "off\n");
615 #ifdef CONFIG_SUSPEND
616 if (state < PM_SUSPEND_MAX)
617 return sprintf(buf, "%s\n", pm_states[state] ?
618 pm_states[state] : "error");
620 #ifdef CONFIG_HIBERNATION
621 return sprintf(buf, "disk\n");
623 return sprintf(buf, "error");
627 static ssize_t autosleep_store(struct kobject *kobj,
628 struct kobj_attribute *attr,
629 const char *buf, size_t n)
631 suspend_state_t state = decode_state(buf, n);
634 if (state == PM_SUSPEND_ON
635 && strcmp(buf, "off") && strcmp(buf, "off\n"))
638 if (state == PM_SUSPEND_MEM)
639 state = mem_sleep_current;
641 error = pm_autosleep_set_state(state);
642 return error ? error : n;
645 power_attr(autosleep);
646 #endif /* CONFIG_PM_AUTOSLEEP */
648 #ifdef CONFIG_PM_WAKELOCKS
649 static ssize_t wake_lock_show(struct kobject *kobj,
650 struct kobj_attribute *attr,
653 return pm_show_wakelocks(buf, true);
656 static ssize_t wake_lock_store(struct kobject *kobj,
657 struct kobj_attribute *attr,
658 const char *buf, size_t n)
660 int error = pm_wake_lock(buf);
661 return error ? error : n;
664 power_attr(wake_lock);
666 static ssize_t wake_unlock_show(struct kobject *kobj,
667 struct kobj_attribute *attr,
670 return pm_show_wakelocks(buf, false);
673 static ssize_t wake_unlock_store(struct kobject *kobj,
674 struct kobj_attribute *attr,
675 const char *buf, size_t n)
677 int error = pm_wake_unlock(buf);
678 return error ? error : n;
681 power_attr(wake_unlock);
683 #endif /* CONFIG_PM_WAKELOCKS */
684 #endif /* CONFIG_PM_SLEEP */
686 #ifdef CONFIG_PM_TRACE
687 int pm_trace_enabled;
689 static ssize_t pm_trace_show(struct kobject *kobj, struct kobj_attribute *attr,
692 return sprintf(buf, "%d\n", pm_trace_enabled);
696 pm_trace_store(struct kobject *kobj, struct kobj_attribute *attr,
697 const char *buf, size_t n)
701 if (sscanf(buf, "%d", &val) == 1) {
702 pm_trace_enabled = !!val;
703 if (pm_trace_enabled) {
704 pr_warn("PM: Enabling pm_trace changes system date and time during resume.\n"
705 "PM: Correct system time has to be restored manually after resume.\n");
712 power_attr(pm_trace);
714 static ssize_t pm_trace_dev_match_show(struct kobject *kobj,
715 struct kobj_attribute *attr,
718 return show_trace_dev_match(buf, PAGE_SIZE);
721 power_attr_ro(pm_trace_dev_match);
723 #endif /* CONFIG_PM_TRACE */
725 #ifdef CONFIG_FREEZER
726 static ssize_t pm_freeze_timeout_show(struct kobject *kobj,
727 struct kobj_attribute *attr, char *buf)
729 return sprintf(buf, "%u\n", freeze_timeout_msecs);
732 static ssize_t pm_freeze_timeout_store(struct kobject *kobj,
733 struct kobj_attribute *attr,
734 const char *buf, size_t n)
738 if (kstrtoul(buf, 10, &val))
741 freeze_timeout_msecs = val;
745 power_attr(pm_freeze_timeout);
747 #endif /* CONFIG_FREEZER*/
749 static struct attribute * g[] = {
751 #ifdef CONFIG_PM_TRACE
753 &pm_trace_dev_match_attr.attr,
755 #ifdef CONFIG_PM_SLEEP
757 &wakeup_count_attr.attr,
758 #ifdef CONFIG_SUSPEND
759 &mem_sleep_attr.attr,
761 #ifdef CONFIG_PM_AUTOSLEEP
762 &autosleep_attr.attr,
764 #ifdef CONFIG_PM_WAKELOCKS
765 &wake_lock_attr.attr,
766 &wake_unlock_attr.attr,
768 #ifdef CONFIG_PM_SLEEP_DEBUG
770 &pm_print_times_attr.attr,
771 &pm_wakeup_irq_attr.attr,
772 &pm_debug_messages_attr.attr,
775 #ifdef CONFIG_FREEZER
776 &pm_freeze_timeout_attr.attr,
781 static const struct attribute_group attr_group = {
785 struct workqueue_struct *pm_wq;
786 EXPORT_SYMBOL_GPL(pm_wq);
788 static int __init pm_start_workqueue(void)
790 pm_wq = alloc_workqueue("pm", WQ_FREEZABLE, 0);
792 return pm_wq ? 0 : -ENOMEM;
795 static int __init pm_init(void)
797 int error = pm_start_workqueue();
800 hibernate_image_size_init();
801 hibernate_reserved_size_init();
803 power_kobj = kobject_create_and_add("power", NULL);
806 error = sysfs_create_group(power_kobj, &attr_group);
809 pm_print_times_init();
810 return pm_autosleep_init();
813 core_initcall(pm_init);