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/resume-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 /* Routines for PM-transition notifications */
27 static BLOCKING_NOTIFIER_HEAD(pm_chain_head);
29 int register_pm_notifier(struct notifier_block *nb)
31 return blocking_notifier_chain_register(&pm_chain_head, nb);
33 EXPORT_SYMBOL_GPL(register_pm_notifier);
35 int unregister_pm_notifier(struct notifier_block *nb)
37 return blocking_notifier_chain_unregister(&pm_chain_head, nb);
39 EXPORT_SYMBOL_GPL(unregister_pm_notifier);
41 int pm_notifier_call_chain(unsigned long val)
43 int ret = blocking_notifier_call_chain(&pm_chain_head, val, NULL);
45 return notifier_to_errno(ret);
48 /* If set, devices may be suspended and resumed asynchronously. */
49 int pm_async_enabled = 1;
51 static ssize_t pm_async_show(struct kobject *kobj, struct kobj_attribute *attr,
54 return sprintf(buf, "%d\n", pm_async_enabled);
57 static ssize_t pm_async_store(struct kobject *kobj, struct kobj_attribute *attr,
58 const char *buf, size_t n)
62 if (kstrtoul(buf, 10, &val))
68 pm_async_enabled = val;
74 #ifdef CONFIG_PM_DEBUG
75 int pm_test_level = TEST_NONE;
77 static const char * const pm_tests[__TEST_AFTER_LAST] = {
80 [TEST_CPUS] = "processors",
81 [TEST_PLATFORM] = "platform",
82 [TEST_DEVICES] = "devices",
83 [TEST_FREEZER] = "freezer",
86 static ssize_t pm_test_show(struct kobject *kobj, struct kobj_attribute *attr,
92 for (level = TEST_FIRST; level <= TEST_MAX; level++)
93 if (pm_tests[level]) {
94 if (level == pm_test_level)
95 s += sprintf(s, "[%s] ", pm_tests[level]);
97 s += sprintf(s, "%s ", pm_tests[level]);
101 /* convert the last space to a newline */
107 static ssize_t pm_test_store(struct kobject *kobj, struct kobj_attribute *attr,
108 const char *buf, size_t n)
110 const char * const *s;
116 p = memchr(buf, '\n', n);
117 len = p ? p - buf : n;
122 for (s = &pm_tests[level]; level <= TEST_MAX; s++, level++)
123 if (*s && len == strlen(*s) && !strncmp(buf, *s, len)) {
124 pm_test_level = level;
129 unlock_system_sleep();
131 return error ? error : n;
135 #endif /* CONFIG_PM_DEBUG */
137 #ifdef CONFIG_DEBUG_FS
138 static char *suspend_step_name(enum suspend_stat_step step)
143 case SUSPEND_PREPARE:
145 case SUSPEND_SUSPEND:
147 case SUSPEND_SUSPEND_NOIRQ:
148 return "suspend_noirq";
149 case SUSPEND_RESUME_NOIRQ:
150 return "resume_noirq";
158 static int suspend_stats_show(struct seq_file *s, void *unused)
160 int i, index, last_dev, last_errno, last_step;
162 last_dev = suspend_stats.last_failed_dev + REC_FAILED_NUM - 1;
163 last_dev %= REC_FAILED_NUM;
164 last_errno = suspend_stats.last_failed_errno + REC_FAILED_NUM - 1;
165 last_errno %= REC_FAILED_NUM;
166 last_step = suspend_stats.last_failed_step + REC_FAILED_NUM - 1;
167 last_step %= REC_FAILED_NUM;
168 seq_printf(s, "%s: %d\n%s: %d\n%s: %d\n%s: %d\n%s: %d\n"
169 "%s: %d\n%s: %d\n%s: %d\n%s: %d\n%s: %d\n",
170 "success", suspend_stats.success,
171 "fail", suspend_stats.fail,
172 "failed_freeze", suspend_stats.failed_freeze,
173 "failed_prepare", suspend_stats.failed_prepare,
174 "failed_suspend", suspend_stats.failed_suspend,
175 "failed_suspend_late",
176 suspend_stats.failed_suspend_late,
177 "failed_suspend_noirq",
178 suspend_stats.failed_suspend_noirq,
179 "failed_resume", suspend_stats.failed_resume,
180 "failed_resume_early",
181 suspend_stats.failed_resume_early,
182 "failed_resume_noirq",
183 suspend_stats.failed_resume_noirq);
184 seq_printf(s, "failures:\n last_failed_dev:\t%-s\n",
185 suspend_stats.failed_devs[last_dev]);
186 for (i = 1; i < REC_FAILED_NUM; i++) {
187 index = last_dev + REC_FAILED_NUM - i;
188 index %= REC_FAILED_NUM;
189 seq_printf(s, "\t\t\t%-s\n",
190 suspend_stats.failed_devs[index]);
192 seq_printf(s, " last_failed_errno:\t%-d\n",
193 suspend_stats.errno[last_errno]);
194 for (i = 1; i < REC_FAILED_NUM; i++) {
195 index = last_errno + REC_FAILED_NUM - i;
196 index %= REC_FAILED_NUM;
197 seq_printf(s, "\t\t\t%-d\n",
198 suspend_stats.errno[index]);
200 seq_printf(s, " last_failed_step:\t%-s\n",
202 suspend_stats.failed_steps[last_step]));
203 for (i = 1; i < REC_FAILED_NUM; i++) {
204 index = last_step + REC_FAILED_NUM - i;
205 index %= REC_FAILED_NUM;
206 seq_printf(s, "\t\t\t%-s\n",
208 suspend_stats.failed_steps[index]));
214 static int suspend_stats_open(struct inode *inode, struct file *file)
216 return single_open(file, suspend_stats_show, NULL);
219 static const struct file_operations suspend_stats_operations = {
220 .open = suspend_stats_open,
223 .release = single_release,
226 static int __init pm_debugfs_init(void)
228 debugfs_create_file("suspend_stats", S_IFREG | S_IRUGO,
229 NULL, NULL, &suspend_stats_operations);
233 late_initcall(pm_debugfs_init);
234 #endif /* CONFIG_DEBUG_FS */
236 #endif /* CONFIG_PM_SLEEP */
238 #ifdef CONFIG_PM_SLEEP_DEBUG
240 * pm_print_times: print time taken by devices to suspend and resume.
242 * show() returns whether printing of suspend and resume times is enabled.
243 * store() accepts 0 or 1. 0 disables printing and 1 enables it.
245 bool pm_print_times_enabled;
247 static ssize_t pm_print_times_show(struct kobject *kobj,
248 struct kobj_attribute *attr, char *buf)
250 return sprintf(buf, "%d\n", pm_print_times_enabled);
253 static ssize_t pm_print_times_store(struct kobject *kobj,
254 struct kobj_attribute *attr,
255 const char *buf, size_t n)
259 if (kstrtoul(buf, 10, &val))
265 pm_print_times_enabled = !!val;
269 power_attr(pm_print_times);
271 static inline void pm_print_times_init(void)
273 pm_print_times_enabled = !!initcall_debug;
275 #else /* !CONFIG_PP_SLEEP_DEBUG */
276 static inline void pm_print_times_init(void) {}
277 #endif /* CONFIG_PM_SLEEP_DEBUG */
279 struct kobject *power_kobj;
282 * state - control system power state.
284 * show() returns what states are supported, which is hard-coded to
285 * 'standby' (Power-On Suspend), 'mem' (Suspend-to-RAM), and
286 * 'disk' (Suspend-to-Disk).
288 * store() accepts one of those strings, translates it into the
289 * proper enumerated value, and initiates a suspend transition.
291 static ssize_t state_show(struct kobject *kobj, struct kobj_attribute *attr,
295 #ifdef CONFIG_SUSPEND
298 for (i = PM_SUSPEND_MIN; i < PM_SUSPEND_MAX; i++)
299 if (pm_states[i].state)
300 s += sprintf(s,"%s ", pm_states[i].label);
303 #ifdef CONFIG_HIBERNATION
304 s += sprintf(s, "%s\n", "disk");
307 /* convert the last space to a newline */
313 static suspend_state_t decode_state(const char *buf, size_t n)
315 #ifdef CONFIG_SUSPEND
316 suspend_state_t state = PM_SUSPEND_MIN;
317 struct pm_sleep_state *s;
322 p = memchr(buf, '\n', n);
323 len = p ? p - buf : n;
325 /* Check hibernation first. */
326 if (len == 4 && !strncmp(buf, "disk", len))
327 return PM_SUSPEND_MAX;
329 #ifdef CONFIG_SUSPEND
330 for (s = &pm_states[state]; state < PM_SUSPEND_MAX; s++, state++)
331 if (s->state && len == strlen(s->label)
332 && !strncmp(buf, s->label, len))
336 return PM_SUSPEND_ON;
339 static ssize_t state_store(struct kobject *kobj, struct kobj_attribute *attr,
340 const char *buf, size_t n)
342 suspend_state_t state;
345 error = pm_autosleep_lock();
349 if (pm_autosleep_state() > PM_SUSPEND_ON) {
354 state = decode_state(buf, n);
355 if (state < PM_SUSPEND_MAX)
356 error = pm_suspend(state);
357 else if (state == PM_SUSPEND_MAX)
363 pm_autosleep_unlock();
364 return error ? error : n;
369 #ifdef CONFIG_PM_SLEEP
371 * The 'wakeup_count' attribute, along with the functions defined in
372 * drivers/base/power/wakeup.c, provides a means by which wakeup events can be
373 * handled in a non-racy way.
375 * If a wakeup event occurs when the system is in a sleep state, it simply is
376 * woken up. In turn, if an event that would wake the system up from a sleep
377 * state occurs when it is undergoing a transition to that sleep state, the
378 * transition should be aborted. Moreover, if such an event occurs when the
379 * system is in the working state, an attempt to start a transition to the
380 * given sleep state should fail during certain period after the detection of
381 * the event. Using the 'state' attribute alone is not sufficient to satisfy
382 * these requirements, because a wakeup event may occur exactly when 'state'
383 * is being written to and may be delivered to user space right before it is
384 * frozen, so the event will remain only partially processed until the system is
385 * woken up by another event. In particular, it won't cause the transition to
386 * a sleep state to be aborted.
388 * This difficulty may be overcome if user space uses 'wakeup_count' before
389 * writing to 'state'. It first should read from 'wakeup_count' and store
390 * the read value. Then, after carrying out its own preparations for the system
391 * transition to a sleep state, it should write the stored value to
392 * 'wakeup_count'. If that fails, at least one wakeup event has occurred since
393 * 'wakeup_count' was read and 'state' should not be written to. Otherwise, it
394 * is allowed to write to 'state', but the transition will be aborted if there
395 * are any wakeup events detected after 'wakeup_count' was written to.
398 static ssize_t wakeup_count_show(struct kobject *kobj,
399 struct kobj_attribute *attr,
404 return pm_get_wakeup_count(&val, true) ?
405 sprintf(buf, "%u\n", val) : -EINTR;
408 static ssize_t wakeup_count_store(struct kobject *kobj,
409 struct kobj_attribute *attr,
410 const char *buf, size_t n)
415 error = pm_autosleep_lock();
419 if (pm_autosleep_state() > PM_SUSPEND_ON) {
425 if (sscanf(buf, "%u", &val) == 1) {
426 if (pm_save_wakeup_count(val))
431 pm_autosleep_unlock();
435 power_attr(wakeup_count);
437 #ifdef CONFIG_PM_AUTOSLEEP
438 static ssize_t autosleep_show(struct kobject *kobj,
439 struct kobj_attribute *attr,
442 suspend_state_t state = pm_autosleep_state();
444 if (state == PM_SUSPEND_ON)
445 return sprintf(buf, "off\n");
447 #ifdef CONFIG_SUSPEND
448 if (state < PM_SUSPEND_MAX)
449 return sprintf(buf, "%s\n", pm_states[state].state ?
450 pm_states[state].label : "error");
452 #ifdef CONFIG_HIBERNATION
453 return sprintf(buf, "disk\n");
455 return sprintf(buf, "error");
459 static ssize_t autosleep_store(struct kobject *kobj,
460 struct kobj_attribute *attr,
461 const char *buf, size_t n)
463 suspend_state_t state = decode_state(buf, n);
466 if (state == PM_SUSPEND_ON
467 && strcmp(buf, "off") && strcmp(buf, "off\n"))
470 error = pm_autosleep_set_state(state);
471 return error ? error : n;
474 power_attr(autosleep);
475 #endif /* CONFIG_PM_AUTOSLEEP */
477 #ifdef CONFIG_PM_WAKELOCKS
478 static ssize_t wake_lock_show(struct kobject *kobj,
479 struct kobj_attribute *attr,
482 return pm_show_wakelocks(buf, true);
485 static ssize_t wake_lock_store(struct kobject *kobj,
486 struct kobj_attribute *attr,
487 const char *buf, size_t n)
489 int error = pm_wake_lock(buf);
490 return error ? error : n;
493 power_attr(wake_lock);
495 static ssize_t wake_unlock_show(struct kobject *kobj,
496 struct kobj_attribute *attr,
499 return pm_show_wakelocks(buf, false);
502 static ssize_t wake_unlock_store(struct kobject *kobj,
503 struct kobj_attribute *attr,
504 const char *buf, size_t n)
506 int error = pm_wake_unlock(buf);
507 return error ? error : n;
510 power_attr(wake_unlock);
512 #endif /* CONFIG_PM_WAKELOCKS */
513 #endif /* CONFIG_PM_SLEEP */
515 #ifdef CONFIG_PM_TRACE
516 int pm_trace_enabled;
518 static ssize_t pm_trace_show(struct kobject *kobj, struct kobj_attribute *attr,
521 return sprintf(buf, "%d\n", pm_trace_enabled);
525 pm_trace_store(struct kobject *kobj, struct kobj_attribute *attr,
526 const char *buf, size_t n)
530 if (sscanf(buf, "%d", &val) == 1) {
531 pm_trace_enabled = !!val;
537 power_attr(pm_trace);
539 static ssize_t pm_trace_dev_match_show(struct kobject *kobj,
540 struct kobj_attribute *attr,
543 return show_trace_dev_match(buf, PAGE_SIZE);
547 pm_trace_dev_match_store(struct kobject *kobj, struct kobj_attribute *attr,
548 const char *buf, size_t n)
553 power_attr(pm_trace_dev_match);
555 #endif /* CONFIG_PM_TRACE */
557 #ifdef CONFIG_FREEZER
558 static ssize_t pm_freeze_timeout_show(struct kobject *kobj,
559 struct kobj_attribute *attr, char *buf)
561 return sprintf(buf, "%u\n", freeze_timeout_msecs);
564 static ssize_t pm_freeze_timeout_store(struct kobject *kobj,
565 struct kobj_attribute *attr,
566 const char *buf, size_t n)
570 if (kstrtoul(buf, 10, &val))
573 freeze_timeout_msecs = val;
577 power_attr(pm_freeze_timeout);
579 #endif /* CONFIG_FREEZER*/
581 static struct attribute * g[] = {
583 #ifdef CONFIG_PM_TRACE
585 &pm_trace_dev_match_attr.attr,
587 #ifdef CONFIG_PM_SLEEP
589 &wakeup_count_attr.attr,
590 #ifdef CONFIG_PM_AUTOSLEEP
591 &autosleep_attr.attr,
593 #ifdef CONFIG_PM_WAKELOCKS
594 &wake_lock_attr.attr,
595 &wake_unlock_attr.attr,
597 #ifdef CONFIG_PM_DEBUG
600 #ifdef CONFIG_PM_SLEEP_DEBUG
601 &pm_print_times_attr.attr,
604 #ifdef CONFIG_FREEZER
605 &pm_freeze_timeout_attr.attr,
610 static struct attribute_group attr_group = {
614 #ifdef CONFIG_PM_RUNTIME
615 struct workqueue_struct *pm_wq;
616 EXPORT_SYMBOL_GPL(pm_wq);
618 static int __init pm_start_workqueue(void)
620 pm_wq = alloc_workqueue("pm", WQ_FREEZABLE, 0);
622 return pm_wq ? 0 : -ENOMEM;
625 static inline int pm_start_workqueue(void) { return 0; }
628 static int __init pm_init(void)
630 int error = pm_start_workqueue();
633 hibernate_image_size_init();
634 hibernate_reserved_size_init();
635 power_kobj = kobject_create_and_add("power", NULL);
638 error = sysfs_create_group(power_kobj, &attr_group);
641 pm_print_times_init();
642 return pm_autosleep_init();
645 core_initcall(pm_init);