xref: /openbmc/linux/kernel/power/main.c (revision d2999e1b)
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/resume-trace.h>
15 #include <linux/workqueue.h>
16 #include <linux/debugfs.h>
17 #include <linux/seq_file.h>
18 
19 #include "power.h"
20 
21 DEFINE_MUTEX(pm_mutex);
22 
23 #ifdef CONFIG_PM_SLEEP
24 
25 /* Routines for PM-transition notifications */
26 
27 static BLOCKING_NOTIFIER_HEAD(pm_chain_head);
28 
29 int register_pm_notifier(struct notifier_block *nb)
30 {
31 	return blocking_notifier_chain_register(&pm_chain_head, nb);
32 }
33 EXPORT_SYMBOL_GPL(register_pm_notifier);
34 
35 int unregister_pm_notifier(struct notifier_block *nb)
36 {
37 	return blocking_notifier_chain_unregister(&pm_chain_head, nb);
38 }
39 EXPORT_SYMBOL_GPL(unregister_pm_notifier);
40 
41 int pm_notifier_call_chain(unsigned long val)
42 {
43 	int ret = blocking_notifier_call_chain(&pm_chain_head, val, NULL);
44 
45 	return notifier_to_errno(ret);
46 }
47 
48 /* If set, devices may be suspended and resumed asynchronously. */
49 int pm_async_enabled = 1;
50 
51 static ssize_t pm_async_show(struct kobject *kobj, struct kobj_attribute *attr,
52 			     char *buf)
53 {
54 	return sprintf(buf, "%d\n", pm_async_enabled);
55 }
56 
57 static ssize_t pm_async_store(struct kobject *kobj, struct kobj_attribute *attr,
58 			      const char *buf, size_t n)
59 {
60 	unsigned long val;
61 
62 	if (kstrtoul(buf, 10, &val))
63 		return -EINVAL;
64 
65 	if (val > 1)
66 		return -EINVAL;
67 
68 	pm_async_enabled = val;
69 	return n;
70 }
71 
72 power_attr(pm_async);
73 
74 #ifdef CONFIG_PM_DEBUG
75 int pm_test_level = TEST_NONE;
76 
77 static const char * const pm_tests[__TEST_AFTER_LAST] = {
78 	[TEST_NONE] = "none",
79 	[TEST_CORE] = "core",
80 	[TEST_CPUS] = "processors",
81 	[TEST_PLATFORM] = "platform",
82 	[TEST_DEVICES] = "devices",
83 	[TEST_FREEZER] = "freezer",
84 };
85 
86 static ssize_t pm_test_show(struct kobject *kobj, struct kobj_attribute *attr,
87 				char *buf)
88 {
89 	char *s = buf;
90 	int level;
91 
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]);
96 			else
97 				s += sprintf(s, "%s ", pm_tests[level]);
98 		}
99 
100 	if (s != buf)
101 		/* convert the last space to a newline */
102 		*(s-1) = '\n';
103 
104 	return (s - buf);
105 }
106 
107 static ssize_t pm_test_store(struct kobject *kobj, struct kobj_attribute *attr,
108 				const char *buf, size_t n)
109 {
110 	const char * const *s;
111 	int level;
112 	char *p;
113 	int len;
114 	int error = -EINVAL;
115 
116 	p = memchr(buf, '\n', n);
117 	len = p ? p - buf : n;
118 
119 	lock_system_sleep();
120 
121 	level = TEST_FIRST;
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;
125 			error = 0;
126 			break;
127 		}
128 
129 	unlock_system_sleep();
130 
131 	return error ? error : n;
132 }
133 
134 power_attr(pm_test);
135 #endif /* CONFIG_PM_DEBUG */
136 
137 #ifdef CONFIG_DEBUG_FS
138 static char *suspend_step_name(enum suspend_stat_step step)
139 {
140 	switch (step) {
141 	case SUSPEND_FREEZE:
142 		return "freeze";
143 	case SUSPEND_PREPARE:
144 		return "prepare";
145 	case SUSPEND_SUSPEND:
146 		return "suspend";
147 	case SUSPEND_SUSPEND_NOIRQ:
148 		return "suspend_noirq";
149 	case SUSPEND_RESUME_NOIRQ:
150 		return "resume_noirq";
151 	case SUSPEND_RESUME:
152 		return "resume";
153 	default:
154 		return "";
155 	}
156 }
157 
158 static int suspend_stats_show(struct seq_file *s, void *unused)
159 {
160 	int i, index, last_dev, last_errno, last_step;
161 
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]);
191 	}
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]);
199 	}
200 	seq_printf(s,	"  last_failed_step:\t%-s\n",
201 			suspend_step_name(
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",
207 			suspend_step_name(
208 				suspend_stats.failed_steps[index]));
209 	}
210 
211 	return 0;
212 }
213 
214 static int suspend_stats_open(struct inode *inode, struct file *file)
215 {
216 	return single_open(file, suspend_stats_show, NULL);
217 }
218 
219 static const struct file_operations suspend_stats_operations = {
220 	.open           = suspend_stats_open,
221 	.read           = seq_read,
222 	.llseek         = seq_lseek,
223 	.release        = single_release,
224 };
225 
226 static int __init pm_debugfs_init(void)
227 {
228 	debugfs_create_file("suspend_stats", S_IFREG | S_IRUGO,
229 			NULL, NULL, &suspend_stats_operations);
230 	return 0;
231 }
232 
233 late_initcall(pm_debugfs_init);
234 #endif /* CONFIG_DEBUG_FS */
235 
236 #endif /* CONFIG_PM_SLEEP */
237 
238 #ifdef CONFIG_PM_SLEEP_DEBUG
239 /*
240  * pm_print_times: print time taken by devices to suspend and resume.
241  *
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.
244  */
245 bool pm_print_times_enabled;
246 
247 static ssize_t pm_print_times_show(struct kobject *kobj,
248 				   struct kobj_attribute *attr, char *buf)
249 {
250 	return sprintf(buf, "%d\n", pm_print_times_enabled);
251 }
252 
253 static ssize_t pm_print_times_store(struct kobject *kobj,
254 				    struct kobj_attribute *attr,
255 				    const char *buf, size_t n)
256 {
257 	unsigned long val;
258 
259 	if (kstrtoul(buf, 10, &val))
260 		return -EINVAL;
261 
262 	if (val > 1)
263 		return -EINVAL;
264 
265 	pm_print_times_enabled = !!val;
266 	return n;
267 }
268 
269 power_attr(pm_print_times);
270 
271 static inline void pm_print_times_init(void)
272 {
273 	pm_print_times_enabled = !!initcall_debug;
274 }
275 #else /* !CONFIG_PP_SLEEP_DEBUG */
276 static inline void pm_print_times_init(void) {}
277 #endif /* CONFIG_PM_SLEEP_DEBUG */
278 
279 struct kobject *power_kobj;
280 
281 /**
282  * state - control system sleep states.
283  *
284  * show() returns available sleep state labels, which may be "mem", "standby",
285  * "freeze" and "disk" (hibernation).  See Documentation/power/states.txt for a
286  * description of what they mean.
287  *
288  * store() accepts one of those strings, translates it into the proper
289  * enumerated value, and initiates a suspend transition.
290  */
291 static ssize_t state_show(struct kobject *kobj, struct kobj_attribute *attr,
292 			  char *buf)
293 {
294 	char *s = buf;
295 #ifdef CONFIG_SUSPEND
296 	suspend_state_t i;
297 
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);
301 
302 #endif
303 	if (hibernation_available())
304 		s += sprintf(s, "disk ");
305 	if (s != buf)
306 		/* convert the last space to a newline */
307 		*(s-1) = '\n';
308 	return (s - buf);
309 }
310 
311 static suspend_state_t decode_state(const char *buf, size_t n)
312 {
313 #ifdef CONFIG_SUSPEND
314 	suspend_state_t state = PM_SUSPEND_MIN;
315 	struct pm_sleep_state *s;
316 #endif
317 	char *p;
318 	int len;
319 
320 	p = memchr(buf, '\n', n);
321 	len = p ? p - buf : n;
322 
323 	/* Check hibernation first. */
324 	if (len == 4 && !strncmp(buf, "disk", len))
325 		return PM_SUSPEND_MAX;
326 
327 #ifdef CONFIG_SUSPEND
328 	for (s = &pm_states[state]; state < PM_SUSPEND_MAX; s++, state++)
329 		if (s->state && len == strlen(s->label)
330 		    && !strncmp(buf, s->label, len))
331 			return s->state;
332 #endif
333 
334 	return PM_SUSPEND_ON;
335 }
336 
337 static ssize_t state_store(struct kobject *kobj, struct kobj_attribute *attr,
338 			   const char *buf, size_t n)
339 {
340 	suspend_state_t state;
341 	int error;
342 
343 	error = pm_autosleep_lock();
344 	if (error)
345 		return error;
346 
347 	if (pm_autosleep_state() > PM_SUSPEND_ON) {
348 		error = -EBUSY;
349 		goto out;
350 	}
351 
352 	state = decode_state(buf, n);
353 	if (state < PM_SUSPEND_MAX)
354 		error = pm_suspend(state);
355 	else if (state == PM_SUSPEND_MAX)
356 		error = hibernate();
357 	else
358 		error = -EINVAL;
359 
360  out:
361 	pm_autosleep_unlock();
362 	return error ? error : n;
363 }
364 
365 power_attr(state);
366 
367 #ifdef CONFIG_PM_SLEEP
368 /*
369  * The 'wakeup_count' attribute, along with the functions defined in
370  * drivers/base/power/wakeup.c, provides a means by which wakeup events can be
371  * handled in a non-racy way.
372  *
373  * If a wakeup event occurs when the system is in a sleep state, it simply is
374  * woken up.  In turn, if an event that would wake the system up from a sleep
375  * state occurs when it is undergoing a transition to that sleep state, the
376  * transition should be aborted.  Moreover, if such an event occurs when the
377  * system is in the working state, an attempt to start a transition to the
378  * given sleep state should fail during certain period after the detection of
379  * the event.  Using the 'state' attribute alone is not sufficient to satisfy
380  * these requirements, because a wakeup event may occur exactly when 'state'
381  * is being written to and may be delivered to user space right before it is
382  * frozen, so the event will remain only partially processed until the system is
383  * woken up by another event.  In particular, it won't cause the transition to
384  * a sleep state to be aborted.
385  *
386  * This difficulty may be overcome if user space uses 'wakeup_count' before
387  * writing to 'state'.  It first should read from 'wakeup_count' and store
388  * the read value.  Then, after carrying out its own preparations for the system
389  * transition to a sleep state, it should write the stored value to
390  * 'wakeup_count'.  If that fails, at least one wakeup event has occurred since
391  * 'wakeup_count' was read and 'state' should not be written to.  Otherwise, it
392  * is allowed to write to 'state', but the transition will be aborted if there
393  * are any wakeup events detected after 'wakeup_count' was written to.
394  */
395 
396 static ssize_t wakeup_count_show(struct kobject *kobj,
397 				struct kobj_attribute *attr,
398 				char *buf)
399 {
400 	unsigned int val;
401 
402 	return pm_get_wakeup_count(&val, true) ?
403 		sprintf(buf, "%u\n", val) : -EINTR;
404 }
405 
406 static ssize_t wakeup_count_store(struct kobject *kobj,
407 				struct kobj_attribute *attr,
408 				const char *buf, size_t n)
409 {
410 	unsigned int val;
411 	int error;
412 
413 	error = pm_autosleep_lock();
414 	if (error)
415 		return error;
416 
417 	if (pm_autosleep_state() > PM_SUSPEND_ON) {
418 		error = -EBUSY;
419 		goto out;
420 	}
421 
422 	error = -EINVAL;
423 	if (sscanf(buf, "%u", &val) == 1) {
424 		if (pm_save_wakeup_count(val))
425 			error = n;
426 		else
427 			pm_print_active_wakeup_sources();
428 	}
429 
430  out:
431 	pm_autosleep_unlock();
432 	return error;
433 }
434 
435 power_attr(wakeup_count);
436 
437 #ifdef CONFIG_PM_AUTOSLEEP
438 static ssize_t autosleep_show(struct kobject *kobj,
439 			      struct kobj_attribute *attr,
440 			      char *buf)
441 {
442 	suspend_state_t state = pm_autosleep_state();
443 
444 	if (state == PM_SUSPEND_ON)
445 		return sprintf(buf, "off\n");
446 
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");
451 #endif
452 #ifdef CONFIG_HIBERNATION
453 	return sprintf(buf, "disk\n");
454 #else
455 	return sprintf(buf, "error");
456 #endif
457 }
458 
459 static ssize_t autosleep_store(struct kobject *kobj,
460 			       struct kobj_attribute *attr,
461 			       const char *buf, size_t n)
462 {
463 	suspend_state_t state = decode_state(buf, n);
464 	int error;
465 
466 	if (state == PM_SUSPEND_ON
467 	    && strcmp(buf, "off") && strcmp(buf, "off\n"))
468 		return -EINVAL;
469 
470 	error = pm_autosleep_set_state(state);
471 	return error ? error : n;
472 }
473 
474 power_attr(autosleep);
475 #endif /* CONFIG_PM_AUTOSLEEP */
476 
477 #ifdef CONFIG_PM_WAKELOCKS
478 static ssize_t wake_lock_show(struct kobject *kobj,
479 			      struct kobj_attribute *attr,
480 			      char *buf)
481 {
482 	return pm_show_wakelocks(buf, true);
483 }
484 
485 static ssize_t wake_lock_store(struct kobject *kobj,
486 			       struct kobj_attribute *attr,
487 			       const char *buf, size_t n)
488 {
489 	int error = pm_wake_lock(buf);
490 	return error ? error : n;
491 }
492 
493 power_attr(wake_lock);
494 
495 static ssize_t wake_unlock_show(struct kobject *kobj,
496 				struct kobj_attribute *attr,
497 				char *buf)
498 {
499 	return pm_show_wakelocks(buf, false);
500 }
501 
502 static ssize_t wake_unlock_store(struct kobject *kobj,
503 				 struct kobj_attribute *attr,
504 				 const char *buf, size_t n)
505 {
506 	int error = pm_wake_unlock(buf);
507 	return error ? error : n;
508 }
509 
510 power_attr(wake_unlock);
511 
512 #endif /* CONFIG_PM_WAKELOCKS */
513 #endif /* CONFIG_PM_SLEEP */
514 
515 #ifdef CONFIG_PM_TRACE
516 int pm_trace_enabled;
517 
518 static ssize_t pm_trace_show(struct kobject *kobj, struct kobj_attribute *attr,
519 			     char *buf)
520 {
521 	return sprintf(buf, "%d\n", pm_trace_enabled);
522 }
523 
524 static ssize_t
525 pm_trace_store(struct kobject *kobj, struct kobj_attribute *attr,
526 	       const char *buf, size_t n)
527 {
528 	int val;
529 
530 	if (sscanf(buf, "%d", &val) == 1) {
531 		pm_trace_enabled = !!val;
532 		if (pm_trace_enabled) {
533 			pr_warn("PM: Enabling pm_trace changes system date and time during resume.\n"
534 				"PM: Correct system time has to be restored manually after resume.\n");
535 		}
536 		return n;
537 	}
538 	return -EINVAL;
539 }
540 
541 power_attr(pm_trace);
542 
543 static ssize_t pm_trace_dev_match_show(struct kobject *kobj,
544 				       struct kobj_attribute *attr,
545 				       char *buf)
546 {
547 	return show_trace_dev_match(buf, PAGE_SIZE);
548 }
549 
550 static ssize_t
551 pm_trace_dev_match_store(struct kobject *kobj, struct kobj_attribute *attr,
552 			 const char *buf, size_t n)
553 {
554 	return -EINVAL;
555 }
556 
557 power_attr(pm_trace_dev_match);
558 
559 #endif /* CONFIG_PM_TRACE */
560 
561 #ifdef CONFIG_FREEZER
562 static ssize_t pm_freeze_timeout_show(struct kobject *kobj,
563 				      struct kobj_attribute *attr, char *buf)
564 {
565 	return sprintf(buf, "%u\n", freeze_timeout_msecs);
566 }
567 
568 static ssize_t pm_freeze_timeout_store(struct kobject *kobj,
569 				       struct kobj_attribute *attr,
570 				       const char *buf, size_t n)
571 {
572 	unsigned long val;
573 
574 	if (kstrtoul(buf, 10, &val))
575 		return -EINVAL;
576 
577 	freeze_timeout_msecs = val;
578 	return n;
579 }
580 
581 power_attr(pm_freeze_timeout);
582 
583 #endif	/* CONFIG_FREEZER*/
584 
585 static struct attribute * g[] = {
586 	&state_attr.attr,
587 #ifdef CONFIG_PM_TRACE
588 	&pm_trace_attr.attr,
589 	&pm_trace_dev_match_attr.attr,
590 #endif
591 #ifdef CONFIG_PM_SLEEP
592 	&pm_async_attr.attr,
593 	&wakeup_count_attr.attr,
594 #ifdef CONFIG_PM_AUTOSLEEP
595 	&autosleep_attr.attr,
596 #endif
597 #ifdef CONFIG_PM_WAKELOCKS
598 	&wake_lock_attr.attr,
599 	&wake_unlock_attr.attr,
600 #endif
601 #ifdef CONFIG_PM_DEBUG
602 	&pm_test_attr.attr,
603 #endif
604 #ifdef CONFIG_PM_SLEEP_DEBUG
605 	&pm_print_times_attr.attr,
606 #endif
607 #endif
608 #ifdef CONFIG_FREEZER
609 	&pm_freeze_timeout_attr.attr,
610 #endif
611 	NULL,
612 };
613 
614 static struct attribute_group attr_group = {
615 	.attrs = g,
616 };
617 
618 #ifdef CONFIG_PM_RUNTIME
619 struct workqueue_struct *pm_wq;
620 EXPORT_SYMBOL_GPL(pm_wq);
621 
622 static int __init pm_start_workqueue(void)
623 {
624 	pm_wq = alloc_workqueue("pm", WQ_FREEZABLE, 0);
625 
626 	return pm_wq ? 0 : -ENOMEM;
627 }
628 #else
629 static inline int pm_start_workqueue(void) { return 0; }
630 #endif
631 
632 static int __init pm_init(void)
633 {
634 	int error = pm_start_workqueue();
635 	if (error)
636 		return error;
637 	hibernate_image_size_init();
638 	hibernate_reserved_size_init();
639 	power_kobj = kobject_create_and_add("power", NULL);
640 	if (!power_kobj)
641 		return -ENOMEM;
642 	error = sysfs_create_group(power_kobj, &attr_group);
643 	if (error)
644 		return error;
645 	pm_print_times_init();
646 	return pm_autosleep_init();
647 }
648 
649 core_initcall(pm_init);
650