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

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