Input: uinput - add a schedule point in uinput_inject_events()
[muen/linux.git] / kernel / power / suspend.c
1 /*
2  * kernel/power/suspend.c - Suspend to RAM and standby functionality.
3  *
4  * Copyright (c) 2003 Patrick Mochel
5  * Copyright (c) 2003 Open Source Development Lab
6  * Copyright (c) 2009 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc.
7  *
8  * This file is released under the GPLv2.
9  */
10
11 #define pr_fmt(fmt) "PM: " fmt
12
13 #include <linux/string.h>
14 #include <linux/delay.h>
15 #include <linux/errno.h>
16 #include <linux/init.h>
17 #include <linux/console.h>
18 #include <linux/cpu.h>
19 #include <linux/cpuidle.h>
20 #include <linux/syscalls.h>
21 #include <linux/gfp.h>
22 #include <linux/io.h>
23 #include <linux/kernel.h>
24 #include <linux/list.h>
25 #include <linux/mm.h>
26 #include <linux/slab.h>
27 #include <linux/export.h>
28 #include <linux/suspend.h>
29 #include <linux/syscore_ops.h>
30 #include <linux/ftrace.h>
31 #include <trace/events/power.h>
32 #include <linux/compiler.h>
33 #include <linux/moduleparam.h>
34
35 #include "power.h"
36
37 const char * const pm_labels[] = {
38         [PM_SUSPEND_TO_IDLE] = "freeze",
39         [PM_SUSPEND_STANDBY] = "standby",
40         [PM_SUSPEND_MEM] = "mem",
41 };
42 const char *pm_states[PM_SUSPEND_MAX];
43 static const char * const mem_sleep_labels[] = {
44         [PM_SUSPEND_TO_IDLE] = "s2idle",
45         [PM_SUSPEND_STANDBY] = "shallow",
46         [PM_SUSPEND_MEM] = "deep",
47 };
48 const char *mem_sleep_states[PM_SUSPEND_MAX];
49
50 suspend_state_t mem_sleep_current = PM_SUSPEND_TO_IDLE;
51 suspend_state_t mem_sleep_default = PM_SUSPEND_MAX;
52 suspend_state_t pm_suspend_target_state;
53 EXPORT_SYMBOL_GPL(pm_suspend_target_state);
54
55 unsigned int pm_suspend_global_flags;
56 EXPORT_SYMBOL_GPL(pm_suspend_global_flags);
57
58 static const struct platform_suspend_ops *suspend_ops;
59 static const struct platform_s2idle_ops *s2idle_ops;
60 static DECLARE_WAIT_QUEUE_HEAD(s2idle_wait_head);
61
62 enum s2idle_states __read_mostly s2idle_state;
63 static DEFINE_SPINLOCK(s2idle_lock);
64
65 bool pm_suspend_via_s2idle(void)
66 {
67         return mem_sleep_current == PM_SUSPEND_TO_IDLE;
68 }
69 EXPORT_SYMBOL_GPL(pm_suspend_via_s2idle);
70
71 void s2idle_set_ops(const struct platform_s2idle_ops *ops)
72 {
73         lock_system_sleep();
74         s2idle_ops = ops;
75         unlock_system_sleep();
76 }
77
78 static void s2idle_begin(void)
79 {
80         s2idle_state = S2IDLE_STATE_NONE;
81 }
82
83 static void s2idle_enter(void)
84 {
85         trace_suspend_resume(TPS("machine_suspend"), PM_SUSPEND_TO_IDLE, true);
86
87         spin_lock_irq(&s2idle_lock);
88         if (pm_wakeup_pending())
89                 goto out;
90
91         s2idle_state = S2IDLE_STATE_ENTER;
92         spin_unlock_irq(&s2idle_lock);
93
94         get_online_cpus();
95         cpuidle_resume();
96
97         /* Push all the CPUs into the idle loop. */
98         wake_up_all_idle_cpus();
99         /* Make the current CPU wait so it can enter the idle loop too. */
100         wait_event(s2idle_wait_head,
101                    s2idle_state == S2IDLE_STATE_WAKE);
102
103         cpuidle_pause();
104         put_online_cpus();
105
106         spin_lock_irq(&s2idle_lock);
107
108  out:
109         s2idle_state = S2IDLE_STATE_NONE;
110         spin_unlock_irq(&s2idle_lock);
111
112         trace_suspend_resume(TPS("machine_suspend"), PM_SUSPEND_TO_IDLE, false);
113 }
114
115 static void s2idle_loop(void)
116 {
117         pm_pr_dbg("suspend-to-idle\n");
118
119         for (;;) {
120                 int error;
121
122                 dpm_noirq_begin();
123
124                 /*
125                  * Suspend-to-idle equals
126                  * frozen processes + suspended devices + idle processors.
127                  * Thus s2idle_enter() should be called right after
128                  * all devices have been suspended.
129                  *
130                  * Wakeups during the noirq suspend of devices may be spurious,
131                  * so prevent them from terminating the loop right away.
132                  */
133                 error = dpm_noirq_suspend_devices(PMSG_SUSPEND);
134                 if (!error)
135                         s2idle_enter();
136                 else if (error == -EBUSY && pm_wakeup_pending())
137                         error = 0;
138
139                 if (!error && s2idle_ops && s2idle_ops->wake)
140                         s2idle_ops->wake();
141
142                 dpm_noirq_resume_devices(PMSG_RESUME);
143
144                 dpm_noirq_end();
145
146                 if (error)
147                         break;
148
149                 if (s2idle_ops && s2idle_ops->sync)
150                         s2idle_ops->sync();
151
152                 if (pm_wakeup_pending())
153                         break;
154
155                 pm_wakeup_clear(false);
156         }
157
158         pm_pr_dbg("resume from suspend-to-idle\n");
159 }
160
161 void s2idle_wake(void)
162 {
163         unsigned long flags;
164
165         spin_lock_irqsave(&s2idle_lock, flags);
166         if (s2idle_state > S2IDLE_STATE_NONE) {
167                 s2idle_state = S2IDLE_STATE_WAKE;
168                 wake_up(&s2idle_wait_head);
169         }
170         spin_unlock_irqrestore(&s2idle_lock, flags);
171 }
172 EXPORT_SYMBOL_GPL(s2idle_wake);
173
174 static bool valid_state(suspend_state_t state)
175 {
176         /*
177          * PM_SUSPEND_STANDBY and PM_SUSPEND_MEM states need low level
178          * support and need to be valid to the low level
179          * implementation, no valid callback implies that none are valid.
180          */
181         return suspend_ops && suspend_ops->valid && suspend_ops->valid(state);
182 }
183
184 void __init pm_states_init(void)
185 {
186         /* "mem" and "freeze" are always present in /sys/power/state. */
187         pm_states[PM_SUSPEND_MEM] = pm_labels[PM_SUSPEND_MEM];
188         pm_states[PM_SUSPEND_TO_IDLE] = pm_labels[PM_SUSPEND_TO_IDLE];
189         /*
190          * Suspend-to-idle should be supported even without any suspend_ops,
191          * initialize mem_sleep_states[] accordingly here.
192          */
193         mem_sleep_states[PM_SUSPEND_TO_IDLE] = mem_sleep_labels[PM_SUSPEND_TO_IDLE];
194 }
195
196 static int __init mem_sleep_default_setup(char *str)
197 {
198         suspend_state_t state;
199
200         for (state = PM_SUSPEND_TO_IDLE; state <= PM_SUSPEND_MEM; state++)
201                 if (mem_sleep_labels[state] &&
202                     !strcmp(str, mem_sleep_labels[state])) {
203                         mem_sleep_default = state;
204                         break;
205                 }
206
207         return 1;
208 }
209 __setup("mem_sleep_default=", mem_sleep_default_setup);
210
211 /**
212  * suspend_set_ops - Set the global suspend method table.
213  * @ops: Suspend operations to use.
214  */
215 void suspend_set_ops(const struct platform_suspend_ops *ops)
216 {
217         lock_system_sleep();
218
219         suspend_ops = ops;
220
221         if (valid_state(PM_SUSPEND_STANDBY)) {
222                 mem_sleep_states[PM_SUSPEND_STANDBY] = mem_sleep_labels[PM_SUSPEND_STANDBY];
223                 pm_states[PM_SUSPEND_STANDBY] = pm_labels[PM_SUSPEND_STANDBY];
224                 if (mem_sleep_default == PM_SUSPEND_STANDBY)
225                         mem_sleep_current = PM_SUSPEND_STANDBY;
226         }
227         if (valid_state(PM_SUSPEND_MEM)) {
228                 mem_sleep_states[PM_SUSPEND_MEM] = mem_sleep_labels[PM_SUSPEND_MEM];
229                 if (mem_sleep_default >= PM_SUSPEND_MEM)
230                         mem_sleep_current = PM_SUSPEND_MEM;
231         }
232
233         unlock_system_sleep();
234 }
235 EXPORT_SYMBOL_GPL(suspend_set_ops);
236
237 /**
238  * suspend_valid_only_mem - Generic memory-only valid callback.
239  *
240  * Platform drivers that implement mem suspend only and only need to check for
241  * that in their .valid() callback can use this instead of rolling their own
242  * .valid() callback.
243  */
244 int suspend_valid_only_mem(suspend_state_t state)
245 {
246         return state == PM_SUSPEND_MEM;
247 }
248 EXPORT_SYMBOL_GPL(suspend_valid_only_mem);
249
250 static bool sleep_state_supported(suspend_state_t state)
251 {
252         return state == PM_SUSPEND_TO_IDLE || (suspend_ops && suspend_ops->enter);
253 }
254
255 static int platform_suspend_prepare(suspend_state_t state)
256 {
257         return state != PM_SUSPEND_TO_IDLE && suspend_ops->prepare ?
258                 suspend_ops->prepare() : 0;
259 }
260
261 static int platform_suspend_prepare_late(suspend_state_t state)
262 {
263         return state == PM_SUSPEND_TO_IDLE && s2idle_ops && s2idle_ops->prepare ?
264                 s2idle_ops->prepare() : 0;
265 }
266
267 static int platform_suspend_prepare_noirq(suspend_state_t state)
268 {
269         return state != PM_SUSPEND_TO_IDLE && suspend_ops->prepare_late ?
270                 suspend_ops->prepare_late() : 0;
271 }
272
273 static void platform_resume_noirq(suspend_state_t state)
274 {
275         if (state != PM_SUSPEND_TO_IDLE && suspend_ops->wake)
276                 suspend_ops->wake();
277 }
278
279 static void platform_resume_early(suspend_state_t state)
280 {
281         if (state == PM_SUSPEND_TO_IDLE && s2idle_ops && s2idle_ops->restore)
282                 s2idle_ops->restore();
283 }
284
285 static void platform_resume_finish(suspend_state_t state)
286 {
287         if (state != PM_SUSPEND_TO_IDLE && suspend_ops->finish)
288                 suspend_ops->finish();
289 }
290
291 static int platform_suspend_begin(suspend_state_t state)
292 {
293         if (state == PM_SUSPEND_TO_IDLE && s2idle_ops && s2idle_ops->begin)
294                 return s2idle_ops->begin();
295         else if (suspend_ops && suspend_ops->begin)
296                 return suspend_ops->begin(state);
297         else
298                 return 0;
299 }
300
301 static void platform_resume_end(suspend_state_t state)
302 {
303         if (state == PM_SUSPEND_TO_IDLE && s2idle_ops && s2idle_ops->end)
304                 s2idle_ops->end();
305         else if (suspend_ops && suspend_ops->end)
306                 suspend_ops->end();
307 }
308
309 static void platform_recover(suspend_state_t state)
310 {
311         if (state != PM_SUSPEND_TO_IDLE && suspend_ops->recover)
312                 suspend_ops->recover();
313 }
314
315 static bool platform_suspend_again(suspend_state_t state)
316 {
317         return state != PM_SUSPEND_TO_IDLE && suspend_ops->suspend_again ?
318                 suspend_ops->suspend_again() : false;
319 }
320
321 #ifdef CONFIG_PM_DEBUG
322 static unsigned int pm_test_delay = 5;
323 module_param(pm_test_delay, uint, 0644);
324 MODULE_PARM_DESC(pm_test_delay,
325                  "Number of seconds to wait before resuming from suspend test");
326 #endif
327
328 static int suspend_test(int level)
329 {
330 #ifdef CONFIG_PM_DEBUG
331         if (pm_test_level == level) {
332                 pr_info("suspend debug: Waiting for %d second(s).\n",
333                                 pm_test_delay);
334                 mdelay(pm_test_delay * 1000);
335                 return 1;
336         }
337 #endif /* !CONFIG_PM_DEBUG */
338         return 0;
339 }
340
341 /**
342  * suspend_prepare - Prepare for entering system sleep state.
343  *
344  * Common code run for every system sleep state that can be entered (except for
345  * hibernation).  Run suspend notifiers, allocate the "suspend" console and
346  * freeze processes.
347  */
348 static int suspend_prepare(suspend_state_t state)
349 {
350         int error, nr_calls = 0;
351
352         if (!sleep_state_supported(state))
353                 return -EPERM;
354
355         pm_prepare_console();
356
357         error = __pm_notifier_call_chain(PM_SUSPEND_PREPARE, -1, &nr_calls);
358         if (error) {
359                 nr_calls--;
360                 goto Finish;
361         }
362
363         trace_suspend_resume(TPS("freeze_processes"), 0, true);
364         error = suspend_freeze_processes();
365         trace_suspend_resume(TPS("freeze_processes"), 0, false);
366         if (!error)
367                 return 0;
368
369         suspend_stats.failed_freeze++;
370         dpm_save_failed_step(SUSPEND_FREEZE);
371  Finish:
372         __pm_notifier_call_chain(PM_POST_SUSPEND, nr_calls, NULL);
373         pm_restore_console();
374         return error;
375 }
376
377 /* default implementation */
378 void __weak arch_suspend_disable_irqs(void)
379 {
380         local_irq_disable();
381 }
382
383 /* default implementation */
384 void __weak arch_suspend_enable_irqs(void)
385 {
386         local_irq_enable();
387 }
388
389 /**
390  * suspend_enter - Make the system enter the given sleep state.
391  * @state: System sleep state to enter.
392  * @wakeup: Returns information that the sleep state should not be re-entered.
393  *
394  * This function should be called after devices have been suspended.
395  */
396 static int suspend_enter(suspend_state_t state, bool *wakeup)
397 {
398         int error;
399
400         error = platform_suspend_prepare(state);
401         if (error)
402                 goto Platform_finish;
403
404         error = dpm_suspend_late(PMSG_SUSPEND);
405         if (error) {
406                 pr_err("late suspend of devices failed\n");
407                 goto Platform_finish;
408         }
409         error = platform_suspend_prepare_late(state);
410         if (error)
411                 goto Devices_early_resume;
412
413         if (state == PM_SUSPEND_TO_IDLE && pm_test_level != TEST_PLATFORM) {
414                 s2idle_loop();
415                 goto Platform_early_resume;
416         }
417
418         error = dpm_suspend_noirq(PMSG_SUSPEND);
419         if (error) {
420                 pr_err("noirq suspend of devices failed\n");
421                 goto Platform_early_resume;
422         }
423         error = platform_suspend_prepare_noirq(state);
424         if (error)
425                 goto Platform_wake;
426
427         if (suspend_test(TEST_PLATFORM))
428                 goto Platform_wake;
429
430         error = disable_nonboot_cpus();
431         if (error || suspend_test(TEST_CPUS))
432                 goto Enable_cpus;
433
434         arch_suspend_disable_irqs();
435         BUG_ON(!irqs_disabled());
436
437         error = syscore_suspend();
438         if (!error) {
439                 *wakeup = pm_wakeup_pending();
440                 if (!(suspend_test(TEST_CORE) || *wakeup)) {
441                         trace_suspend_resume(TPS("machine_suspend"),
442                                 state, true);
443                         error = suspend_ops->enter(state);
444                         trace_suspend_resume(TPS("machine_suspend"),
445                                 state, false);
446                 } else if (*wakeup) {
447                         error = -EBUSY;
448                 }
449                 syscore_resume();
450         }
451
452         arch_suspend_enable_irqs();
453         BUG_ON(irqs_disabled());
454
455  Enable_cpus:
456         enable_nonboot_cpus();
457
458  Platform_wake:
459         platform_resume_noirq(state);
460         dpm_resume_noirq(PMSG_RESUME);
461
462  Platform_early_resume:
463         platform_resume_early(state);
464
465  Devices_early_resume:
466         dpm_resume_early(PMSG_RESUME);
467
468  Platform_finish:
469         platform_resume_finish(state);
470         return error;
471 }
472
473 /**
474  * suspend_devices_and_enter - Suspend devices and enter system sleep state.
475  * @state: System sleep state to enter.
476  */
477 int suspend_devices_and_enter(suspend_state_t state)
478 {
479         int error;
480         bool wakeup = false;
481
482         if (!sleep_state_supported(state))
483                 return -ENOSYS;
484
485         pm_suspend_target_state = state;
486
487         error = platform_suspend_begin(state);
488         if (error)
489                 goto Close;
490
491         suspend_console();
492         suspend_test_start();
493         error = dpm_suspend_start(PMSG_SUSPEND);
494         if (error) {
495                 pr_err("Some devices failed to suspend, or early wake event detected\n");
496                 goto Recover_platform;
497         }
498         suspend_test_finish("suspend devices");
499         if (suspend_test(TEST_DEVICES))
500                 goto Recover_platform;
501
502         do {
503                 error = suspend_enter(state, &wakeup);
504         } while (!error && !wakeup && platform_suspend_again(state));
505
506  Resume_devices:
507         suspend_test_start();
508         dpm_resume_end(PMSG_RESUME);
509         suspend_test_finish("resume devices");
510         trace_suspend_resume(TPS("resume_console"), state, true);
511         resume_console();
512         trace_suspend_resume(TPS("resume_console"), state, false);
513
514  Close:
515         platform_resume_end(state);
516         pm_suspend_target_state = PM_SUSPEND_ON;
517         return error;
518
519  Recover_platform:
520         platform_recover(state);
521         goto Resume_devices;
522 }
523
524 /**
525  * suspend_finish - Clean up before finishing the suspend sequence.
526  *
527  * Call platform code to clean up, restart processes, and free the console that
528  * we've allocated. This routine is not called for hibernation.
529  */
530 static void suspend_finish(void)
531 {
532         suspend_thaw_processes();
533         pm_notifier_call_chain(PM_POST_SUSPEND);
534         pm_restore_console();
535 }
536
537 /**
538  * enter_state - Do common work needed to enter system sleep state.
539  * @state: System sleep state to enter.
540  *
541  * Make sure that no one else is trying to put the system into a sleep state.
542  * Fail if that's not the case.  Otherwise, prepare for system suspend, make the
543  * system enter the given sleep state and clean up after wakeup.
544  */
545 static int enter_state(suspend_state_t state)
546 {
547         int error;
548
549         trace_suspend_resume(TPS("suspend_enter"), state, true);
550         if (state == PM_SUSPEND_TO_IDLE) {
551 #ifdef CONFIG_PM_DEBUG
552                 if (pm_test_level != TEST_NONE && pm_test_level <= TEST_CPUS) {
553                         pr_warn("Unsupported test mode for suspend to idle, please choose none/freezer/devices/platform.\n");
554                         return -EAGAIN;
555                 }
556 #endif
557         } else if (!valid_state(state)) {
558                 return -EINVAL;
559         }
560         if (!mutex_trylock(&pm_mutex))
561                 return -EBUSY;
562
563         if (state == PM_SUSPEND_TO_IDLE)
564                 s2idle_begin();
565
566 #ifndef CONFIG_SUSPEND_SKIP_SYNC
567         trace_suspend_resume(TPS("sync_filesystems"), 0, true);
568         pr_info("Syncing filesystems ... ");
569         ksys_sync();
570         pr_cont("done.\n");
571         trace_suspend_resume(TPS("sync_filesystems"), 0, false);
572 #endif
573
574         pm_pr_dbg("Preparing system for sleep (%s)\n", mem_sleep_labels[state]);
575         pm_suspend_clear_flags();
576         error = suspend_prepare(state);
577         if (error)
578                 goto Unlock;
579
580         if (suspend_test(TEST_FREEZER))
581                 goto Finish;
582
583         trace_suspend_resume(TPS("suspend_enter"), state, false);
584         pm_pr_dbg("Suspending system (%s)\n", mem_sleep_labels[state]);
585         pm_restrict_gfp_mask();
586         error = suspend_devices_and_enter(state);
587         pm_restore_gfp_mask();
588
589  Finish:
590         events_check_enabled = false;
591         pm_pr_dbg("Finishing wakeup.\n");
592         suspend_finish();
593  Unlock:
594         mutex_unlock(&pm_mutex);
595         return error;
596 }
597
598 /**
599  * pm_suspend - Externally visible function for suspending the system.
600  * @state: System sleep state to enter.
601  *
602  * Check if the value of @state represents one of the supported states,
603  * execute enter_state() and update system suspend statistics.
604  */
605 int pm_suspend(suspend_state_t state)
606 {
607         int error;
608
609         if (state <= PM_SUSPEND_ON || state >= PM_SUSPEND_MAX)
610                 return -EINVAL;
611
612         pr_info("suspend entry (%s)\n", mem_sleep_labels[state]);
613         error = enter_state(state);
614         if (error) {
615                 suspend_stats.fail++;
616                 dpm_save_failed_errno(error);
617         } else {
618                 suspend_stats.success++;
619         }
620         pr_info("suspend exit\n");
621         return error;
622 }
623 EXPORT_SYMBOL(pm_suspend);