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Linux/kernel/power/main.c

  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 
 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 
276 static ssize_t pm_wakeup_irq_show(struct kobject *kobj,
277                                         struct kobj_attribute *attr,
278                                         char *buf)
279 {
280         return pm_wakeup_irq ? sprintf(buf, "%u\n", pm_wakeup_irq) : -ENODATA;
281 }
282 
283 static ssize_t pm_wakeup_irq_store(struct kobject *kobj,
284                                         struct kobj_attribute *attr,
285                                         const char *buf, size_t n)
286 {
287         return -EINVAL;
288 }
289 power_attr(pm_wakeup_irq);
290 
291 #else /* !CONFIG_PM_SLEEP_DEBUG */
292 static inline void pm_print_times_init(void) {}
293 #endif /* CONFIG_PM_SLEEP_DEBUG */
294 
295 struct kobject *power_kobj;
296 
297 /**
298  * state - control system sleep states.
299  *
300  * show() returns available sleep state labels, which may be "mem", "standby",
301  * "freeze" and "disk" (hibernation).  See Documentation/power/states.txt for a
302  * description of what they mean.
303  *
304  * store() accepts one of those strings, translates it into the proper
305  * enumerated value, and initiates a suspend transition.
306  */
307 static ssize_t state_show(struct kobject *kobj, struct kobj_attribute *attr,
308                           char *buf)
309 {
310         char *s = buf;
311 #ifdef CONFIG_SUSPEND
312         suspend_state_t i;
313 
314         for (i = PM_SUSPEND_MIN; i < PM_SUSPEND_MAX; i++)
315                 if (pm_states[i])
316                         s += sprintf(s,"%s ", pm_states[i]);
317 
318 #endif
319         if (hibernation_available())
320                 s += sprintf(s, "disk ");
321         if (s != buf)
322                 /* convert the last space to a newline */
323                 *(s-1) = '\n';
324         return (s - buf);
325 }
326 
327 static suspend_state_t decode_state(const char *buf, size_t n)
328 {
329 #ifdef CONFIG_SUSPEND
330         suspend_state_t state;
331 #endif
332         char *p;
333         int len;
334 
335         p = memchr(buf, '\n', n);
336         len = p ? p - buf : n;
337 
338         /* Check hibernation first. */
339         if (len == 4 && !strncmp(buf, "disk", len))
340                 return PM_SUSPEND_MAX;
341 
342 #ifdef CONFIG_SUSPEND
343         for (state = PM_SUSPEND_MIN; state < PM_SUSPEND_MAX; state++) {
344                 const char *label = pm_states[state];
345 
346                 if (label && len == strlen(label) && !strncmp(buf, label, len))
347                         return state;
348         }
349 #endif
350 
351         return PM_SUSPEND_ON;
352 }
353 
354 static ssize_t state_store(struct kobject *kobj, struct kobj_attribute *attr,
355                            const char *buf, size_t n)
356 {
357         suspend_state_t state;
358         int error;
359 
360         error = pm_autosleep_lock();
361         if (error)
362                 return error;
363 
364         if (pm_autosleep_state() > PM_SUSPEND_ON) {
365                 error = -EBUSY;
366                 goto out;
367         }
368 
369         state = decode_state(buf, n);
370         if (state < PM_SUSPEND_MAX)
371                 error = pm_suspend(state);
372         else if (state == PM_SUSPEND_MAX)
373                 error = hibernate();
374         else
375                 error = -EINVAL;
376 
377  out:
378         pm_autosleep_unlock();
379         return error ? error : n;
380 }
381 
382 power_attr(state);
383 
384 #ifdef CONFIG_PM_SLEEP
385 /*
386  * The 'wakeup_count' attribute, along with the functions defined in
387  * drivers/base/power/wakeup.c, provides a means by which wakeup events can be
388  * handled in a non-racy way.
389  *
390  * If a wakeup event occurs when the system is in a sleep state, it simply is
391  * woken up.  In turn, if an event that would wake the system up from a sleep
392  * state occurs when it is undergoing a transition to that sleep state, the
393  * transition should be aborted.  Moreover, if such an event occurs when the
394  * system is in the working state, an attempt to start a transition to the
395  * given sleep state should fail during certain period after the detection of
396  * the event.  Using the 'state' attribute alone is not sufficient to satisfy
397  * these requirements, because a wakeup event may occur exactly when 'state'
398  * is being written to and may be delivered to user space right before it is
399  * frozen, so the event will remain only partially processed until the system is
400  * woken up by another event.  In particular, it won't cause the transition to
401  * a sleep state to be aborted.
402  *
403  * This difficulty may be overcome if user space uses 'wakeup_count' before
404  * writing to 'state'.  It first should read from 'wakeup_count' and store
405  * the read value.  Then, after carrying out its own preparations for the system
406  * transition to a sleep state, it should write the stored value to
407  * 'wakeup_count'.  If that fails, at least one wakeup event has occurred since
408  * 'wakeup_count' was read and 'state' should not be written to.  Otherwise, it
409  * is allowed to write to 'state', but the transition will be aborted if there
410  * are any wakeup events detected after 'wakeup_count' was written to.
411  */
412 
413 static ssize_t wakeup_count_show(struct kobject *kobj,
414                                 struct kobj_attribute *attr,
415                                 char *buf)
416 {
417         unsigned int val;
418 
419         return pm_get_wakeup_count(&val, true) ?
420                 sprintf(buf, "%u\n", val) : -EINTR;
421 }
422 
423 static ssize_t wakeup_count_store(struct kobject *kobj,
424                                 struct kobj_attribute *attr,
425                                 const char *buf, size_t n)
426 {
427         unsigned int val;
428         int error;
429 
430         error = pm_autosleep_lock();
431         if (error)
432                 return error;
433 
434         if (pm_autosleep_state() > PM_SUSPEND_ON) {
435                 error = -EBUSY;
436                 goto out;
437         }
438 
439         error = -EINVAL;
440         if (sscanf(buf, "%u", &val) == 1) {
441                 if (pm_save_wakeup_count(val))
442                         error = n;
443                 else
444                         pm_print_active_wakeup_sources();
445         }
446 
447  out:
448         pm_autosleep_unlock();
449         return error;
450 }
451 
452 power_attr(wakeup_count);
453 
454 #ifdef CONFIG_PM_AUTOSLEEP
455 static ssize_t autosleep_show(struct kobject *kobj,
456                               struct kobj_attribute *attr,
457                               char *buf)
458 {
459         suspend_state_t state = pm_autosleep_state();
460 
461         if (state == PM_SUSPEND_ON)
462                 return sprintf(buf, "off\n");
463 
464 #ifdef CONFIG_SUSPEND
465         if (state < PM_SUSPEND_MAX)
466                 return sprintf(buf, "%s\n", pm_states[state] ?
467                                         pm_states[state] : "error");
468 #endif
469 #ifdef CONFIG_HIBERNATION
470         return sprintf(buf, "disk\n");
471 #else
472         return sprintf(buf, "error");
473 #endif
474 }
475 
476 static ssize_t autosleep_store(struct kobject *kobj,
477                                struct kobj_attribute *attr,
478                                const char *buf, size_t n)
479 {
480         suspend_state_t state = decode_state(buf, n);
481         int error;
482 
483         if (state == PM_SUSPEND_ON
484             && strcmp(buf, "off") && strcmp(buf, "off\n"))
485                 return -EINVAL;
486 
487         error = pm_autosleep_set_state(state);
488         return error ? error : n;
489 }
490 
491 power_attr(autosleep);
492 #endif /* CONFIG_PM_AUTOSLEEP */
493 
494 #ifdef CONFIG_PM_WAKELOCKS
495 static ssize_t wake_lock_show(struct kobject *kobj,
496                               struct kobj_attribute *attr,
497                               char *buf)
498 {
499         return pm_show_wakelocks(buf, true);
500 }
501 
502 static ssize_t wake_lock_store(struct kobject *kobj,
503                                struct kobj_attribute *attr,
504                                const char *buf, size_t n)
505 {
506         int error = pm_wake_lock(buf);
507         return error ? error : n;
508 }
509 
510 power_attr(wake_lock);
511 
512 static ssize_t wake_unlock_show(struct kobject *kobj,
513                                 struct kobj_attribute *attr,
514                                 char *buf)
515 {
516         return pm_show_wakelocks(buf, false);
517 }
518 
519 static ssize_t wake_unlock_store(struct kobject *kobj,
520                                  struct kobj_attribute *attr,
521                                  const char *buf, size_t n)
522 {
523         int error = pm_wake_unlock(buf);
524         return error ? error : n;
525 }
526 
527 power_attr(wake_unlock);
528 
529 #endif /* CONFIG_PM_WAKELOCKS */
530 #endif /* CONFIG_PM_SLEEP */
531 
532 #ifdef CONFIG_PM_TRACE
533 int pm_trace_enabled;
534 
535 static ssize_t pm_trace_show(struct kobject *kobj, struct kobj_attribute *attr,
536                              char *buf)
537 {
538         return sprintf(buf, "%d\n", pm_trace_enabled);
539 }
540 
541 static ssize_t
542 pm_trace_store(struct kobject *kobj, struct kobj_attribute *attr,
543                const char *buf, size_t n)
544 {
545         int val;
546 
547         if (sscanf(buf, "%d", &val) == 1) {
548                 pm_trace_enabled = !!val;
549                 if (pm_trace_enabled) {
550                         pr_warn("PM: Enabling pm_trace changes system date and time during resume.\n"
551                                 "PM: Correct system time has to be restored manually after resume.\n");
552                 }
553                 return n;
554         }
555         return -EINVAL;
556 }
557 
558 power_attr(pm_trace);
559 
560 static ssize_t pm_trace_dev_match_show(struct kobject *kobj,
561                                        struct kobj_attribute *attr,
562                                        char *buf)
563 {
564         return show_trace_dev_match(buf, PAGE_SIZE);
565 }
566 
567 static ssize_t
568 pm_trace_dev_match_store(struct kobject *kobj, struct kobj_attribute *attr,
569                          const char *buf, size_t n)
570 {
571         return -EINVAL;
572 }
573 
574 power_attr(pm_trace_dev_match);
575 
576 #endif /* CONFIG_PM_TRACE */
577 
578 #ifdef CONFIG_FREEZER
579 static ssize_t pm_freeze_timeout_show(struct kobject *kobj,
580                                       struct kobj_attribute *attr, char *buf)
581 {
582         return sprintf(buf, "%u\n", freeze_timeout_msecs);
583 }
584 
585 static ssize_t pm_freeze_timeout_store(struct kobject *kobj,
586                                        struct kobj_attribute *attr,
587                                        const char *buf, size_t n)
588 {
589         unsigned long val;
590 
591         if (kstrtoul(buf, 10, &val))
592                 return -EINVAL;
593 
594         freeze_timeout_msecs = val;
595         return n;
596 }
597 
598 power_attr(pm_freeze_timeout);
599 
600 #endif  /* CONFIG_FREEZER*/
601 
602 static struct attribute * g[] = {
603         &state_attr.attr,
604 #ifdef CONFIG_PM_TRACE
605         &pm_trace_attr.attr,
606         &pm_trace_dev_match_attr.attr,
607 #endif
608 #ifdef CONFIG_PM_SLEEP
609         &pm_async_attr.attr,
610         &wakeup_count_attr.attr,
611 #ifdef CONFIG_PM_AUTOSLEEP
612         &autosleep_attr.attr,
613 #endif
614 #ifdef CONFIG_PM_WAKELOCKS
615         &wake_lock_attr.attr,
616         &wake_unlock_attr.attr,
617 #endif
618 #ifdef CONFIG_PM_DEBUG
619         &pm_test_attr.attr,
620 #endif
621 #ifdef CONFIG_PM_SLEEP_DEBUG
622         &pm_print_times_attr.attr,
623         &pm_wakeup_irq_attr.attr,
624 #endif
625 #endif
626 #ifdef CONFIG_FREEZER
627         &pm_freeze_timeout_attr.attr,
628 #endif
629         NULL,
630 };
631 
632 static struct attribute_group attr_group = {
633         .attrs = g,
634 };
635 
636 struct workqueue_struct *pm_wq;
637 EXPORT_SYMBOL_GPL(pm_wq);
638 
639 static int __init pm_start_workqueue(void)
640 {
641         pm_wq = alloc_workqueue("pm", WQ_FREEZABLE, 0);
642 
643         return pm_wq ? 0 : -ENOMEM;
644 }
645 
646 static int __init pm_init(void)
647 {
648         int error = pm_start_workqueue();
649         if (error)
650                 return error;
651         hibernate_image_size_init();
652         hibernate_reserved_size_init();
653         power_kobj = kobject_create_and_add("power", NULL);
654         if (!power_kobj)
655                 return -ENOMEM;
656         error = sysfs_create_group(power_kobj, &attr_group);
657         if (error)
658                 return error;
659         pm_print_times_init();
660         return pm_autosleep_init();
661 }
662 
663 core_initcall(pm_init);
664 

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