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Linux/kernel/power/main.c

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  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 power state.
283  *
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).
287  *
288  *      store() accepts one of those strings, translates it into the
289  *      proper 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 #ifdef CONFIG_HIBERNATION
304         s += sprintf(s, "%s\n", "disk");
305 #else
306         if (s != buf)
307                 /* convert the last space to a newline */
308                 *(s-1) = '\n';
309 #endif
310         return (s - buf);
311 }
312 
313 static suspend_state_t decode_state(const char *buf, size_t n)
314 {
315 #ifdef CONFIG_SUSPEND
316         suspend_state_t state = PM_SUSPEND_MIN;
317         struct pm_sleep_state *s;
318 #endif
319         char *p;
320         int len;
321 
322         p = memchr(buf, '\n', n);
323         len = p ? p - buf : n;
324 
325         /* Check hibernation first. */
326         if (len == 4 && !strncmp(buf, "disk", len))
327                 return PM_SUSPEND_MAX;
328 
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))
333                         return s->state;
334 #endif
335 
336         return PM_SUSPEND_ON;
337 }
338 
339 static ssize_t state_store(struct kobject *kobj, struct kobj_attribute *attr,
340                            const char *buf, size_t n)
341 {
342         suspend_state_t state;
343         int error;
344 
345         error = pm_autosleep_lock();
346         if (error)
347                 return error;
348 
349         if (pm_autosleep_state() > PM_SUSPEND_ON) {
350                 error = -EBUSY;
351                 goto out;
352         }
353 
354         state = decode_state(buf, n);
355         if (state < PM_SUSPEND_MAX)
356                 error = pm_suspend(state);
357         else if (state == PM_SUSPEND_MAX)
358                 error = hibernate();
359         else
360                 error = -EINVAL;
361 
362  out:
363         pm_autosleep_unlock();
364         return error ? error : n;
365 }
366 
367 power_attr(state);
368 
369 #ifdef CONFIG_PM_SLEEP
370 /*
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.
374  *
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.
387  *
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.
396  */
397 
398 static ssize_t wakeup_count_show(struct kobject *kobj,
399                                 struct kobj_attribute *attr,
400                                 char *buf)
401 {
402         unsigned int val;
403 
404         return pm_get_wakeup_count(&val, true) ?
405                 sprintf(buf, "%u\n", val) : -EINTR;
406 }
407 
408 static ssize_t wakeup_count_store(struct kobject *kobj,
409                                 struct kobj_attribute *attr,
410                                 const char *buf, size_t n)
411 {
412         unsigned int val;
413         int error;
414 
415         error = pm_autosleep_lock();
416         if (error)
417                 return error;
418 
419         if (pm_autosleep_state() > PM_SUSPEND_ON) {
420                 error = -EBUSY;
421                 goto out;
422         }
423 
424         error = -EINVAL;
425         if (sscanf(buf, "%u", &val) == 1) {
426                 if (pm_save_wakeup_count(val))
427                         error = n;
428                 else
429                         pm_print_active_wakeup_sources();
430         }
431 
432  out:
433         pm_autosleep_unlock();
434         return error;
435 }
436 
437 power_attr(wakeup_count);
438 
439 #ifdef CONFIG_PM_AUTOSLEEP
440 static ssize_t autosleep_show(struct kobject *kobj,
441                               struct kobj_attribute *attr,
442                               char *buf)
443 {
444         suspend_state_t state = pm_autosleep_state();
445 
446         if (state == PM_SUSPEND_ON)
447                 return sprintf(buf, "off\n");
448 
449 #ifdef CONFIG_SUSPEND
450         if (state < PM_SUSPEND_MAX)
451                 return sprintf(buf, "%s\n", pm_states[state].state ?
452                                         pm_states[state].label : "error");
453 #endif
454 #ifdef CONFIG_HIBERNATION
455         return sprintf(buf, "disk\n");
456 #else
457         return sprintf(buf, "error");
458 #endif
459 }
460 
461 static ssize_t autosleep_store(struct kobject *kobj,
462                                struct kobj_attribute *attr,
463                                const char *buf, size_t n)
464 {
465         suspend_state_t state = decode_state(buf, n);
466         int error;
467 
468         if (state == PM_SUSPEND_ON
469             && strcmp(buf, "off") && strcmp(buf, "off\n"))
470                 return -EINVAL;
471 
472         error = pm_autosleep_set_state(state);
473         return error ? error : n;
474 }
475 
476 power_attr(autosleep);
477 #endif /* CONFIG_PM_AUTOSLEEP */
478 
479 #ifdef CONFIG_PM_WAKELOCKS
480 static ssize_t wake_lock_show(struct kobject *kobj,
481                               struct kobj_attribute *attr,
482                               char *buf)
483 {
484         return pm_show_wakelocks(buf, true);
485 }
486 
487 static ssize_t wake_lock_store(struct kobject *kobj,
488                                struct kobj_attribute *attr,
489                                const char *buf, size_t n)
490 {
491         int error = pm_wake_lock(buf);
492         return error ? error : n;
493 }
494 
495 power_attr(wake_lock);
496 
497 static ssize_t wake_unlock_show(struct kobject *kobj,
498                                 struct kobj_attribute *attr,
499                                 char *buf)
500 {
501         return pm_show_wakelocks(buf, false);
502 }
503 
504 static ssize_t wake_unlock_store(struct kobject *kobj,
505                                  struct kobj_attribute *attr,
506                                  const char *buf, size_t n)
507 {
508         int error = pm_wake_unlock(buf);
509         return error ? error : n;
510 }
511 
512 power_attr(wake_unlock);
513 
514 #endif /* CONFIG_PM_WAKELOCKS */
515 #endif /* CONFIG_PM_SLEEP */
516 
517 #ifdef CONFIG_PM_TRACE
518 int pm_trace_enabled;
519 
520 static ssize_t pm_trace_show(struct kobject *kobj, struct kobj_attribute *attr,
521                              char *buf)
522 {
523         return sprintf(buf, "%d\n", pm_trace_enabled);
524 }
525 
526 static ssize_t
527 pm_trace_store(struct kobject *kobj, struct kobj_attribute *attr,
528                const char *buf, size_t n)
529 {
530         int val;
531 
532         if (sscanf(buf, "%d", &val) == 1) {
533                 pm_trace_enabled = !!val;
534                 if (pm_trace_enabled) {
535                         pr_warn("PM: Enabling pm_trace changes system date and time during resume.\n"
536                                 "PM: Correct system time has to be restored manually after resume.\n");
537                 }
538                 return n;
539         }
540         return -EINVAL;
541 }
542 
543 power_attr(pm_trace);
544 
545 static ssize_t pm_trace_dev_match_show(struct kobject *kobj,
546                                        struct kobj_attribute *attr,
547                                        char *buf)
548 {
549         return show_trace_dev_match(buf, PAGE_SIZE);
550 }
551 
552 static ssize_t
553 pm_trace_dev_match_store(struct kobject *kobj, struct kobj_attribute *attr,
554                          const char *buf, size_t n)
555 {
556         return -EINVAL;
557 }
558 
559 power_attr(pm_trace_dev_match);
560 
561 #endif /* CONFIG_PM_TRACE */
562 
563 #ifdef CONFIG_FREEZER
564 static ssize_t pm_freeze_timeout_show(struct kobject *kobj,
565                                       struct kobj_attribute *attr, char *buf)
566 {
567         return sprintf(buf, "%u\n", freeze_timeout_msecs);
568 }
569 
570 static ssize_t pm_freeze_timeout_store(struct kobject *kobj,
571                                        struct kobj_attribute *attr,
572                                        const char *buf, size_t n)
573 {
574         unsigned long val;
575 
576         if (kstrtoul(buf, 10, &val))
577                 return -EINVAL;
578 
579         freeze_timeout_msecs = val;
580         return n;
581 }
582 
583 power_attr(pm_freeze_timeout);
584 
585 #endif  /* CONFIG_FREEZER*/
586 
587 static struct attribute * g[] = {
588         &state_attr.attr,
589 #ifdef CONFIG_PM_TRACE
590         &pm_trace_attr.attr,
591         &pm_trace_dev_match_attr.attr,
592 #endif
593 #ifdef CONFIG_PM_SLEEP
594         &pm_async_attr.attr,
595         &wakeup_count_attr.attr,
596 #ifdef CONFIG_PM_AUTOSLEEP
597         &autosleep_attr.attr,
598 #endif
599 #ifdef CONFIG_PM_WAKELOCKS
600         &wake_lock_attr.attr,
601         &wake_unlock_attr.attr,
602 #endif
603 #ifdef CONFIG_PM_DEBUG
604         &pm_test_attr.attr,
605 #endif
606 #ifdef CONFIG_PM_SLEEP_DEBUG
607         &pm_print_times_attr.attr,
608 #endif
609 #endif
610 #ifdef CONFIG_FREEZER
611         &pm_freeze_timeout_attr.attr,
612 #endif
613         NULL,
614 };
615 
616 static struct attribute_group attr_group = {
617         .attrs = g,
618 };
619 
620 #ifdef CONFIG_PM_RUNTIME
621 struct workqueue_struct *pm_wq;
622 EXPORT_SYMBOL_GPL(pm_wq);
623 
624 static int __init pm_start_workqueue(void)
625 {
626         pm_wq = alloc_workqueue("pm", WQ_FREEZABLE, 0);
627 
628         return pm_wq ? 0 : -ENOMEM;
629 }
630 #else
631 static inline int pm_start_workqueue(void) { return 0; }
632 #endif
633 
634 static int __init pm_init(void)
635 {
636         int error = pm_start_workqueue();
637         if (error)
638                 return error;
639         hibernate_image_size_init();
640         hibernate_reserved_size_init();
641         power_kobj = kobject_create_and_add("power", NULL);
642         if (!power_kobj)
643                 return -ENOMEM;
644         error = sysfs_create_group(power_kobj, &attr_group);
645         if (error)
646                 return error;
647         pm_print_times_init();
648         return pm_autosleep_init();
649 }
650 
651 core_initcall(pm_init);
652 

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