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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/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 

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