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>
21 DEFINE_MUTEX(pm_mutex);
23 #ifdef CONFIG_PM_SLEEP
25 void lock_system_sleep(void)
27 current->flags |= PF_FREEZER_SKIP;
28 mutex_lock(&pm_mutex);
30 EXPORT_SYMBOL_GPL(lock_system_sleep);
32 void unlock_system_sleep(void)
35 * Don't use freezer_count() because we don't want the call to
36 * try_to_freeze() here.
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.
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(&pm_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]));
322 static int suspend_stats_open(struct inode *inode, struct file *file)
324 return single_open(file, suspend_stats_show, NULL);
327 static const struct file_operations suspend_stats_operations = {
328 .open = suspend_stats_open,
331 .release = single_release,
334 static int __init pm_debugfs_init(void)
336 debugfs_create_file("suspend_stats", S_IFREG | S_IRUGO,
337 NULL, NULL, &suspend_stats_operations);
341 late_initcall(pm_debugfs_init);
342 #endif /* CONFIG_DEBUG_FS */
344 #endif /* CONFIG_PM_SLEEP */
346 #ifdef CONFIG_PM_SLEEP_DEBUG
348 * pm_print_times: print time taken by devices to suspend and resume.
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.
353 bool pm_print_times_enabled;
355 static ssize_t pm_print_times_show(struct kobject *kobj,
356 struct kobj_attribute *attr, char *buf)
358 return sprintf(buf, "%d\n", pm_print_times_enabled);
361 static ssize_t pm_print_times_store(struct kobject *kobj,
362 struct kobj_attribute *attr,
363 const char *buf, size_t n)
367 if (kstrtoul(buf, 10, &val))
373 pm_print_times_enabled = !!val;
377 power_attr(pm_print_times);
379 static inline void pm_print_times_init(void)
381 pm_print_times_enabled = !!initcall_debug;
384 static ssize_t pm_wakeup_irq_show(struct kobject *kobj,
385 struct kobj_attribute *attr,
388 return pm_wakeup_irq ? sprintf(buf, "%u\n", pm_wakeup_irq) : -ENODATA;
391 power_attr_ro(pm_wakeup_irq);
393 bool pm_debug_messages_on __read_mostly;
395 static ssize_t pm_debug_messages_show(struct kobject *kobj,
396 struct kobj_attribute *attr, char *buf)
398 return sprintf(buf, "%d\n", pm_debug_messages_on);
401 static ssize_t pm_debug_messages_store(struct kobject *kobj,
402 struct kobj_attribute *attr,
403 const char *buf, size_t n)
407 if (kstrtoul(buf, 10, &val))
413 pm_debug_messages_on = !!val;
417 power_attr(pm_debug_messages);
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.
424 * The message will be emitted if enabled through the pm_debug_messages
427 void __pm_pr_dbg(bool defer, const char *fmt, ...)
429 struct va_format vaf;
432 if (!pm_debug_messages_on)
441 printk_deferred(KERN_DEBUG "PM: %pV", &vaf);
443 printk(KERN_DEBUG "PM: %pV", &vaf);
448 #else /* !CONFIG_PM_SLEEP_DEBUG */
449 static inline void pm_print_times_init(void) {}
450 #endif /* CONFIG_PM_SLEEP_DEBUG */
452 struct kobject *power_kobj;
455 * state - control system sleep states.
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.
461 * store() accepts one of those strings, translates it into the proper
462 * enumerated value, and initiates a suspend transition.
464 static ssize_t state_show(struct kobject *kobj, struct kobj_attribute *attr,
468 #ifdef CONFIG_SUSPEND
471 for (i = PM_SUSPEND_MIN; i < PM_SUSPEND_MAX; i++)
473 s += sprintf(s,"%s ", pm_states[i]);
476 if (hibernation_available())
477 s += sprintf(s, "disk ");
479 /* convert the last space to a newline */
484 static suspend_state_t decode_state(const char *buf, size_t n)
486 #ifdef CONFIG_SUSPEND
487 suspend_state_t state;
492 p = memchr(buf, '\n', n);
493 len = p ? p - buf : n;
495 /* Check hibernation first. */
496 if (len == 4 && !strncmp(buf, "disk", len))
497 return PM_SUSPEND_MAX;
499 #ifdef CONFIG_SUSPEND
500 for (state = PM_SUSPEND_MIN; state < PM_SUSPEND_MAX; state++) {
501 const char *label = pm_states[state];
503 if (label && len == strlen(label) && !strncmp(buf, label, len))
508 return PM_SUSPEND_ON;
511 static ssize_t state_store(struct kobject *kobj, struct kobj_attribute *attr,
512 const char *buf, size_t n)
514 suspend_state_t state;
517 error = pm_autosleep_lock();
521 if (pm_autosleep_state() > PM_SUSPEND_ON) {
526 state = decode_state(buf, n);
527 if (state < PM_SUSPEND_MAX) {
528 if (state == PM_SUSPEND_MEM)
529 state = mem_sleep_current;
531 error = pm_suspend(state);
532 } else if (state == PM_SUSPEND_MAX) {
539 pm_autosleep_unlock();
540 return error ? error : n;
545 #ifdef CONFIG_PM_SLEEP
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.
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.
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.
574 static ssize_t wakeup_count_show(struct kobject *kobj,
575 struct kobj_attribute *attr,
580 return pm_get_wakeup_count(&val, true) ?
581 sprintf(buf, "%u\n", val) : -EINTR;
584 static ssize_t wakeup_count_store(struct kobject *kobj,
585 struct kobj_attribute *attr,
586 const char *buf, size_t n)
591 error = pm_autosleep_lock();
595 if (pm_autosleep_state() > PM_SUSPEND_ON) {
601 if (sscanf(buf, "%u", &val) == 1) {
602 if (pm_save_wakeup_count(val))
605 pm_print_active_wakeup_sources();
609 pm_autosleep_unlock();
613 power_attr(wakeup_count);
615 #ifdef CONFIG_PM_AUTOSLEEP
616 static ssize_t autosleep_show(struct kobject *kobj,
617 struct kobj_attribute *attr,
620 suspend_state_t state = pm_autosleep_state();
622 if (state == PM_SUSPEND_ON)
623 return sprintf(buf, "off\n");
625 #ifdef CONFIG_SUSPEND
626 if (state < PM_SUSPEND_MAX)
627 return sprintf(buf, "%s\n", pm_states[state] ?
628 pm_states[state] : "error");
630 #ifdef CONFIG_HIBERNATION
631 return sprintf(buf, "disk\n");
633 return sprintf(buf, "error");
637 static ssize_t autosleep_store(struct kobject *kobj,
638 struct kobj_attribute *attr,
639 const char *buf, size_t n)
641 suspend_state_t state = decode_state(buf, n);
644 if (state == PM_SUSPEND_ON
645 && strcmp(buf, "off") && strcmp(buf, "off\n"))
648 if (state == PM_SUSPEND_MEM)
649 state = mem_sleep_current;
651 error = pm_autosleep_set_state(state);
652 return error ? error : n;
655 power_attr(autosleep);
656 #endif /* CONFIG_PM_AUTOSLEEP */
658 #ifdef CONFIG_PM_WAKELOCKS
659 static ssize_t wake_lock_show(struct kobject *kobj,
660 struct kobj_attribute *attr,
663 return pm_show_wakelocks(buf, true);
666 static ssize_t wake_lock_store(struct kobject *kobj,
667 struct kobj_attribute *attr,
668 const char *buf, size_t n)
670 int error = pm_wake_lock(buf);
671 return error ? error : n;
674 power_attr(wake_lock);
676 static ssize_t wake_unlock_show(struct kobject *kobj,
677 struct kobj_attribute *attr,
680 return pm_show_wakelocks(buf, false);
683 static ssize_t wake_unlock_store(struct kobject *kobj,
684 struct kobj_attribute *attr,
685 const char *buf, size_t n)
687 int error = pm_wake_unlock(buf);
688 return error ? error : n;
691 power_attr(wake_unlock);
693 #endif /* CONFIG_PM_WAKELOCKS */
694 #endif /* CONFIG_PM_SLEEP */
696 #ifdef CONFIG_PM_TRACE
697 int pm_trace_enabled;
699 static ssize_t pm_trace_show(struct kobject *kobj, struct kobj_attribute *attr,
702 return sprintf(buf, "%d\n", pm_trace_enabled);
706 pm_trace_store(struct kobject *kobj, struct kobj_attribute *attr,
707 const char *buf, size_t n)
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");
722 power_attr(pm_trace);
724 static ssize_t pm_trace_dev_match_show(struct kobject *kobj,
725 struct kobj_attribute *attr,
728 return show_trace_dev_match(buf, PAGE_SIZE);
731 power_attr_ro(pm_trace_dev_match);
733 #endif /* CONFIG_PM_TRACE */
735 #ifdef CONFIG_FREEZER
736 static ssize_t pm_freeze_timeout_show(struct kobject *kobj,
737 struct kobj_attribute *attr, char *buf)
739 return sprintf(buf, "%u\n", freeze_timeout_msecs);
742 static ssize_t pm_freeze_timeout_store(struct kobject *kobj,
743 struct kobj_attribute *attr,
744 const char *buf, size_t n)
748 if (kstrtoul(buf, 10, &val))
751 freeze_timeout_msecs = val;
755 power_attr(pm_freeze_timeout);
757 #endif /* CONFIG_FREEZER*/
759 static struct attribute * g[] = {
761 #ifdef CONFIG_PM_TRACE
763 &pm_trace_dev_match_attr.attr,
765 #ifdef CONFIG_PM_SLEEP
767 &wakeup_count_attr.attr,
768 #ifdef CONFIG_SUSPEND
769 &mem_sleep_attr.attr,
771 #ifdef CONFIG_PM_AUTOSLEEP
772 &autosleep_attr.attr,
774 #ifdef CONFIG_PM_WAKELOCKS
775 &wake_lock_attr.attr,
776 &wake_unlock_attr.attr,
778 #ifdef CONFIG_PM_SLEEP_DEBUG
780 &pm_print_times_attr.attr,
781 &pm_wakeup_irq_attr.attr,
782 &pm_debug_messages_attr.attr,
785 #ifdef CONFIG_FREEZER
786 &pm_freeze_timeout_attr.attr,
791 static const struct attribute_group attr_group = {
795 struct workqueue_struct *pm_wq;
796 EXPORT_SYMBOL_GPL(pm_wq);
798 static int __init pm_start_workqueue(void)
800 pm_wq = alloc_workqueue("pm", WQ_FREEZABLE, 0);
802 return pm_wq ? 0 : -ENOMEM;
805 static int __init pm_init(void)
807 int error = pm_start_workqueue();
810 hibernate_image_size_init();
811 hibernate_reserved_size_init();
813 power_kobj = kobject_create_and_add("power", NULL);
816 error = sysfs_create_group(power_kobj, &attr_group);
819 pm_print_times_init();
820 return pm_autosleep_init();
823 core_initcall(pm_init);