Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs...
[linux-2.6] / 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/module.h>
12 #include <linux/suspend.h>
13 #include <linux/kobject.h>
14 #include <linux/string.h>
15 #include <linux/delay.h>
16 #include <linux/errno.h>
17 #include <linux/kmod.h>
18 #include <linux/init.h>
19 #include <linux/console.h>
20 #include <linux/cpu.h>
21 #include <linux/resume-trace.h>
22 #include <linux/freezer.h>
23 #include <linux/vmstat.h>
24 #include <linux/syscalls.h>
25 #include <linux/ftrace.h>
26
27 #include "power.h"
28
29 DEFINE_MUTEX(pm_mutex);
30
31 unsigned int pm_flags;
32 EXPORT_SYMBOL(pm_flags);
33
34 #ifdef CONFIG_PM_SLEEP
35
36 /* Routines for PM-transition notifications */
37
38 static BLOCKING_NOTIFIER_HEAD(pm_chain_head);
39
40 int register_pm_notifier(struct notifier_block *nb)
41 {
42         return blocking_notifier_chain_register(&pm_chain_head, nb);
43 }
44 EXPORT_SYMBOL_GPL(register_pm_notifier);
45
46 int unregister_pm_notifier(struct notifier_block *nb)
47 {
48         return blocking_notifier_chain_unregister(&pm_chain_head, nb);
49 }
50 EXPORT_SYMBOL_GPL(unregister_pm_notifier);
51
52 int pm_notifier_call_chain(unsigned long val)
53 {
54         return (blocking_notifier_call_chain(&pm_chain_head, val, NULL)
55                         == NOTIFY_BAD) ? -EINVAL : 0;
56 }
57
58 #ifdef CONFIG_PM_DEBUG
59 int pm_test_level = TEST_NONE;
60
61 static int suspend_test(int level)
62 {
63         if (pm_test_level == level) {
64                 printk(KERN_INFO "suspend debug: Waiting for 5 seconds.\n");
65                 mdelay(5000);
66                 return 1;
67         }
68         return 0;
69 }
70
71 static const char * const pm_tests[__TEST_AFTER_LAST] = {
72         [TEST_NONE] = "none",
73         [TEST_CORE] = "core",
74         [TEST_CPUS] = "processors",
75         [TEST_PLATFORM] = "platform",
76         [TEST_DEVICES] = "devices",
77         [TEST_FREEZER] = "freezer",
78 };
79
80 static ssize_t pm_test_show(struct kobject *kobj, struct kobj_attribute *attr,
81                                 char *buf)
82 {
83         char *s = buf;
84         int level;
85
86         for (level = TEST_FIRST; level <= TEST_MAX; level++)
87                 if (pm_tests[level]) {
88                         if (level == pm_test_level)
89                                 s += sprintf(s, "[%s] ", pm_tests[level]);
90                         else
91                                 s += sprintf(s, "%s ", pm_tests[level]);
92                 }
93
94         if (s != buf)
95                 /* convert the last space to a newline */
96                 *(s-1) = '\n';
97
98         return (s - buf);
99 }
100
101 static ssize_t pm_test_store(struct kobject *kobj, struct kobj_attribute *attr,
102                                 const char *buf, size_t n)
103 {
104         const char * const *s;
105         int level;
106         char *p;
107         int len;
108         int error = -EINVAL;
109
110         p = memchr(buf, '\n', n);
111         len = p ? p - buf : n;
112
113         mutex_lock(&pm_mutex);
114
115         level = TEST_FIRST;
116         for (s = &pm_tests[level]; level <= TEST_MAX; s++, level++)
117                 if (*s && len == strlen(*s) && !strncmp(buf, *s, len)) {
118                         pm_test_level = level;
119                         error = 0;
120                         break;
121                 }
122
123         mutex_unlock(&pm_mutex);
124
125         return error ? error : n;
126 }
127
128 power_attr(pm_test);
129 #else /* !CONFIG_PM_DEBUG */
130 static inline int suspend_test(int level) { return 0; }
131 #endif /* !CONFIG_PM_DEBUG */
132
133 #endif /* CONFIG_PM_SLEEP */
134
135 #ifdef CONFIG_SUSPEND
136
137 #ifdef CONFIG_PM_TEST_SUSPEND
138
139 /*
140  * We test the system suspend code by setting an RTC wakealarm a short
141  * time in the future, then suspending.  Suspending the devices won't
142  * normally take long ... some systems only need a few milliseconds.
143  *
144  * The time it takes is system-specific though, so when we test this
145  * during system bootup we allow a LOT of time.
146  */
147 #define TEST_SUSPEND_SECONDS    5
148
149 static unsigned long suspend_test_start_time;
150
151 static void suspend_test_start(void)
152 {
153         /* FIXME Use better timebase than "jiffies", ideally a clocksource.
154          * What we want is a hardware counter that will work correctly even
155          * during the irqs-are-off stages of the suspend/resume cycle...
156          */
157         suspend_test_start_time = jiffies;
158 }
159
160 static void suspend_test_finish(const char *label)
161 {
162         long nj = jiffies - suspend_test_start_time;
163         unsigned msec;
164
165         msec = jiffies_to_msecs(abs(nj));
166         pr_info("PM: %s took %d.%03d seconds\n", label,
167                         msec / 1000, msec % 1000);
168
169         /* Warning on suspend means the RTC alarm period needs to be
170          * larger -- the system was sooo slooowwww to suspend that the
171          * alarm (should have) fired before the system went to sleep!
172          *
173          * Warning on either suspend or resume also means the system
174          * has some performance issues.  The stack dump of a WARN_ON
175          * is more likely to get the right attention than a printk...
176          */
177         WARN(msec > (TEST_SUSPEND_SECONDS * 1000), "Component: %s\n", label);
178 }
179
180 #else
181
182 static void suspend_test_start(void)
183 {
184 }
185
186 static void suspend_test_finish(const char *label)
187 {
188 }
189
190 #endif
191
192 /* This is just an arbitrary number */
193 #define FREE_PAGE_NUMBER (100)
194
195 static struct platform_suspend_ops *suspend_ops;
196
197 /**
198  *      suspend_set_ops - Set the global suspend method table.
199  *      @ops:   Pointer to ops structure.
200  */
201
202 void suspend_set_ops(struct platform_suspend_ops *ops)
203 {
204         mutex_lock(&pm_mutex);
205         suspend_ops = ops;
206         mutex_unlock(&pm_mutex);
207 }
208
209 /**
210  * suspend_valid_only_mem - generic memory-only valid callback
211  *
212  * Platform drivers that implement mem suspend only and only need
213  * to check for that in their .valid callback can use this instead
214  * of rolling their own .valid callback.
215  */
216 int suspend_valid_only_mem(suspend_state_t state)
217 {
218         return state == PM_SUSPEND_MEM;
219 }
220
221 /**
222  *      suspend_prepare - Do prep work before entering low-power state.
223  *
224  *      This is common code that is called for each state that we're entering.
225  *      Run suspend notifiers, allocate a console and stop all processes.
226  */
227 static int suspend_prepare(void)
228 {
229         int error;
230         unsigned int free_pages;
231
232         if (!suspend_ops || !suspend_ops->enter)
233                 return -EPERM;
234
235         pm_prepare_console();
236
237         error = pm_notifier_call_chain(PM_SUSPEND_PREPARE);
238         if (error)
239                 goto Finish;
240
241         error = usermodehelper_disable();
242         if (error)
243                 goto Finish;
244
245         if (suspend_freeze_processes()) {
246                 error = -EAGAIN;
247                 goto Thaw;
248         }
249
250         free_pages = global_page_state(NR_FREE_PAGES);
251         if (free_pages < FREE_PAGE_NUMBER) {
252                 pr_debug("PM: free some memory\n");
253                 shrink_all_memory(FREE_PAGE_NUMBER - free_pages);
254                 if (nr_free_pages() < FREE_PAGE_NUMBER) {
255                         error = -ENOMEM;
256                         printk(KERN_ERR "PM: No enough memory\n");
257                 }
258         }
259         if (!error)
260                 return 0;
261
262  Thaw:
263         suspend_thaw_processes();
264         usermodehelper_enable();
265  Finish:
266         pm_notifier_call_chain(PM_POST_SUSPEND);
267         pm_restore_console();
268         return error;
269 }
270
271 /* default implementation */
272 void __attribute__ ((weak)) arch_suspend_disable_irqs(void)
273 {
274         local_irq_disable();
275 }
276
277 /* default implementation */
278 void __attribute__ ((weak)) arch_suspend_enable_irqs(void)
279 {
280         local_irq_enable();
281 }
282
283 /**
284  *      suspend_enter - enter the desired system sleep state.
285  *      @state:         state to enter
286  *
287  *      This function should be called after devices have been suspended.
288  */
289 static int suspend_enter(suspend_state_t state)
290 {
291         int error = 0;
292
293         device_pm_lock();
294         arch_suspend_disable_irqs();
295         BUG_ON(!irqs_disabled());
296
297         if ((error = device_power_down(PMSG_SUSPEND))) {
298                 printk(KERN_ERR "PM: Some devices failed to power down\n");
299                 goto Done;
300         }
301
302         if (!suspend_test(TEST_CORE))
303                 error = suspend_ops->enter(state);
304
305         device_power_up(PMSG_RESUME);
306  Done:
307         arch_suspend_enable_irqs();
308         BUG_ON(irqs_disabled());
309         device_pm_unlock();
310         return error;
311 }
312
313 /**
314  *      suspend_devices_and_enter - suspend devices and enter the desired system
315  *                                  sleep state.
316  *      @state:           state to enter
317  */
318 int suspend_devices_and_enter(suspend_state_t state)
319 {
320         int error, ftrace_save;
321
322         if (!suspend_ops)
323                 return -ENOSYS;
324
325         if (suspend_ops->begin) {
326                 error = suspend_ops->begin(state);
327                 if (error)
328                         goto Close;
329         }
330         suspend_console();
331         ftrace_save = __ftrace_enabled_save();
332         suspend_test_start();
333         error = device_suspend(PMSG_SUSPEND);
334         if (error) {
335                 printk(KERN_ERR "PM: Some devices failed to suspend\n");
336                 goto Recover_platform;
337         }
338         suspend_test_finish("suspend devices");
339         if (suspend_test(TEST_DEVICES))
340                 goto Recover_platform;
341
342         if (suspend_ops->prepare) {
343                 error = suspend_ops->prepare();
344                 if (error)
345                         goto Resume_devices;
346         }
347
348         if (suspend_test(TEST_PLATFORM))
349                 goto Finish;
350
351         error = disable_nonboot_cpus();
352         if (!error && !suspend_test(TEST_CPUS))
353                 suspend_enter(state);
354
355         enable_nonboot_cpus();
356  Finish:
357         if (suspend_ops->finish)
358                 suspend_ops->finish();
359  Resume_devices:
360         suspend_test_start();
361         device_resume(PMSG_RESUME);
362         suspend_test_finish("resume devices");
363         __ftrace_enabled_restore(ftrace_save);
364         resume_console();
365  Close:
366         if (suspend_ops->end)
367                 suspend_ops->end();
368         return error;
369
370  Recover_platform:
371         if (suspend_ops->recover)
372                 suspend_ops->recover();
373         goto Resume_devices;
374 }
375
376 /**
377  *      suspend_finish - Do final work before exiting suspend sequence.
378  *
379  *      Call platform code to clean up, restart processes, and free the 
380  *      console that we've allocated. This is not called for suspend-to-disk.
381  */
382 static void suspend_finish(void)
383 {
384         suspend_thaw_processes();
385         usermodehelper_enable();
386         pm_notifier_call_chain(PM_POST_SUSPEND);
387         pm_restore_console();
388 }
389
390
391
392
393 static const char * const pm_states[PM_SUSPEND_MAX] = {
394         [PM_SUSPEND_STANDBY]    = "standby",
395         [PM_SUSPEND_MEM]        = "mem",
396 };
397
398 static inline int valid_state(suspend_state_t state)
399 {
400         /* All states need lowlevel support and need to be valid
401          * to the lowlevel implementation, no valid callback
402          * implies that none are valid. */
403         if (!suspend_ops || !suspend_ops->valid || !suspend_ops->valid(state))
404                 return 0;
405         return 1;
406 }
407
408
409 /**
410  *      enter_state - Do common work of entering low-power state.
411  *      @state:         pm_state structure for state we're entering.
412  *
413  *      Make sure we're the only ones trying to enter a sleep state. Fail
414  *      if someone has beat us to it, since we don't want anything weird to
415  *      happen when we wake up.
416  *      Then, do the setup for suspend, enter the state, and cleaup (after
417  *      we've woken up).
418  */
419 static int enter_state(suspend_state_t state)
420 {
421         int error;
422
423         if (!valid_state(state))
424                 return -ENODEV;
425
426         if (!mutex_trylock(&pm_mutex))
427                 return -EBUSY;
428
429         printk(KERN_INFO "PM: Syncing filesystems ... ");
430         sys_sync();
431         printk("done.\n");
432
433         pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]);
434         error = suspend_prepare();
435         if (error)
436                 goto Unlock;
437
438         if (suspend_test(TEST_FREEZER))
439                 goto Finish;
440
441         pr_debug("PM: Entering %s sleep\n", pm_states[state]);
442         error = suspend_devices_and_enter(state);
443
444  Finish:
445         pr_debug("PM: Finishing wakeup.\n");
446         suspend_finish();
447  Unlock:
448         mutex_unlock(&pm_mutex);
449         return error;
450 }
451
452
453 /**
454  *      pm_suspend - Externally visible function for suspending system.
455  *      @state:         Enumerated value of state to enter.
456  *
457  *      Determine whether or not value is within range, get state 
458  *      structure, and enter (above).
459  */
460
461 int pm_suspend(suspend_state_t state)
462 {
463         if (state > PM_SUSPEND_ON && state <= PM_SUSPEND_MAX)
464                 return enter_state(state);
465         return -EINVAL;
466 }
467
468 EXPORT_SYMBOL(pm_suspend);
469
470 #endif /* CONFIG_SUSPEND */
471
472 struct kobject *power_kobj;
473
474 /**
475  *      state - control system power state.
476  *
477  *      show() returns what states are supported, which is hard-coded to
478  *      'standby' (Power-On Suspend), 'mem' (Suspend-to-RAM), and
479  *      'disk' (Suspend-to-Disk).
480  *
481  *      store() accepts one of those strings, translates it into the 
482  *      proper enumerated value, and initiates a suspend transition.
483  */
484
485 static ssize_t state_show(struct kobject *kobj, struct kobj_attribute *attr,
486                           char *buf)
487 {
488         char *s = buf;
489 #ifdef CONFIG_SUSPEND
490         int i;
491
492         for (i = 0; i < PM_SUSPEND_MAX; i++) {
493                 if (pm_states[i] && valid_state(i))
494                         s += sprintf(s,"%s ", pm_states[i]);
495         }
496 #endif
497 #ifdef CONFIG_HIBERNATION
498         s += sprintf(s, "%s\n", "disk");
499 #else
500         if (s != buf)
501                 /* convert the last space to a newline */
502                 *(s-1) = '\n';
503 #endif
504         return (s - buf);
505 }
506
507 static ssize_t state_store(struct kobject *kobj, struct kobj_attribute *attr,
508                            const char *buf, size_t n)
509 {
510 #ifdef CONFIG_SUSPEND
511         suspend_state_t state = PM_SUSPEND_STANDBY;
512         const char * const *s;
513 #endif
514         char *p;
515         int len;
516         int error = -EINVAL;
517
518         p = memchr(buf, '\n', n);
519         len = p ? p - buf : n;
520
521         /* First, check if we are requested to hibernate */
522         if (len == 4 && !strncmp(buf, "disk", len)) {
523                 error = hibernate();
524   goto Exit;
525         }
526
527 #ifdef CONFIG_SUSPEND
528         for (s = &pm_states[state]; state < PM_SUSPEND_MAX; s++, state++) {
529                 if (*s && len == strlen(*s) && !strncmp(buf, *s, len))
530                         break;
531         }
532         if (state < PM_SUSPEND_MAX && *s)
533                 error = enter_state(state);
534 #endif
535
536  Exit:
537         return error ? error : n;
538 }
539
540 power_attr(state);
541
542 #ifdef CONFIG_PM_TRACE
543 int pm_trace_enabled;
544
545 static ssize_t pm_trace_show(struct kobject *kobj, struct kobj_attribute *attr,
546                              char *buf)
547 {
548         return sprintf(buf, "%d\n", pm_trace_enabled);
549 }
550
551 static ssize_t
552 pm_trace_store(struct kobject *kobj, struct kobj_attribute *attr,
553                const char *buf, size_t n)
554 {
555         int val;
556
557         if (sscanf(buf, "%d", &val) == 1) {
558                 pm_trace_enabled = !!val;
559                 return n;
560         }
561         return -EINVAL;
562 }
563
564 power_attr(pm_trace);
565 #endif /* CONFIG_PM_TRACE */
566
567 static struct attribute * g[] = {
568         &state_attr.attr,
569 #ifdef CONFIG_PM_TRACE
570         &pm_trace_attr.attr,
571 #endif
572 #if defined(CONFIG_PM_SLEEP) && defined(CONFIG_PM_DEBUG)
573         &pm_test_attr.attr,
574 #endif
575         NULL,
576 };
577
578 static struct attribute_group attr_group = {
579         .attrs = g,
580 };
581
582
583 static int __init pm_init(void)
584 {
585         power_kobj = kobject_create_and_add("power", NULL);
586         if (!power_kobj)
587                 return -ENOMEM;
588         return sysfs_create_group(power_kobj, &attr_group);
589 }
590
591 core_initcall(pm_init);
592
593
594 #ifdef CONFIG_PM_TEST_SUSPEND
595
596 #include <linux/rtc.h>
597
598 /*
599  * To test system suspend, we need a hands-off mechanism to resume the
600  * system.  RTCs wake alarms are a common self-contained mechanism.
601  */
602
603 static void __init test_wakealarm(struct rtc_device *rtc, suspend_state_t state)
604 {
605         static char err_readtime[] __initdata =
606                 KERN_ERR "PM: can't read %s time, err %d\n";
607         static char err_wakealarm [] __initdata =
608                 KERN_ERR "PM: can't set %s wakealarm, err %d\n";
609         static char err_suspend[] __initdata =
610                 KERN_ERR "PM: suspend test failed, error %d\n";
611         static char info_test[] __initdata =
612                 KERN_INFO "PM: test RTC wakeup from '%s' suspend\n";
613
614         unsigned long           now;
615         struct rtc_wkalrm       alm;
616         int                     status;
617
618         /* this may fail if the RTC hasn't been initialized */
619         status = rtc_read_time(rtc, &alm.time);
620         if (status < 0) {
621                 printk(err_readtime, rtc->dev.bus_id, status);
622                 return;
623         }
624         rtc_tm_to_time(&alm.time, &now);
625
626         memset(&alm, 0, sizeof alm);
627         rtc_time_to_tm(now + TEST_SUSPEND_SECONDS, &alm.time);
628         alm.enabled = true;
629
630         status = rtc_set_alarm(rtc, &alm);
631         if (status < 0) {
632                 printk(err_wakealarm, rtc->dev.bus_id, status);
633                 return;
634         }
635
636         if (state == PM_SUSPEND_MEM) {
637                 printk(info_test, pm_states[state]);
638                 status = pm_suspend(state);
639                 if (status == -ENODEV)
640                         state = PM_SUSPEND_STANDBY;
641         }
642         if (state == PM_SUSPEND_STANDBY) {
643                 printk(info_test, pm_states[state]);
644                 status = pm_suspend(state);
645         }
646         if (status < 0)
647                 printk(err_suspend, status);
648
649         /* Some platforms can't detect that the alarm triggered the
650          * wakeup, or (accordingly) disable it after it afterwards.
651          * It's supposed to give oneshot behavior; cope.
652          */
653         alm.enabled = false;
654         rtc_set_alarm(rtc, &alm);
655 }
656
657 static int __init has_wakealarm(struct device *dev, void *name_ptr)
658 {
659         struct rtc_device *candidate = to_rtc_device(dev);
660
661         if (!candidate->ops->set_alarm)
662                 return 0;
663         if (!device_may_wakeup(candidate->dev.parent))
664                 return 0;
665
666         *(char **)name_ptr = dev->bus_id;
667         return 1;
668 }
669
670 /*
671  * Kernel options like "test_suspend=mem" force suspend/resume sanity tests
672  * at startup time.  They're normally disabled, for faster boot and because
673  * we can't know which states really work on this particular system.
674  */
675 static suspend_state_t test_state __initdata = PM_SUSPEND_ON;
676
677 static char warn_bad_state[] __initdata =
678         KERN_WARNING "PM: can't test '%s' suspend state\n";
679
680 static int __init setup_test_suspend(char *value)
681 {
682         unsigned i;
683
684         /* "=mem" ==> "mem" */
685         value++;
686         for (i = 0; i < PM_SUSPEND_MAX; i++) {
687                 if (!pm_states[i])
688                         continue;
689                 if (strcmp(pm_states[i], value) != 0)
690                         continue;
691                 test_state = (__force suspend_state_t) i;
692                 return 0;
693         }
694         printk(warn_bad_state, value);
695         return 0;
696 }
697 __setup("test_suspend", setup_test_suspend);
698
699 static int __init test_suspend(void)
700 {
701         static char             warn_no_rtc[] __initdata =
702                 KERN_WARNING "PM: no wakealarm-capable RTC driver is ready\n";
703
704         char                    *pony = NULL;
705         struct rtc_device       *rtc = NULL;
706
707         /* PM is initialized by now; is that state testable? */
708         if (test_state == PM_SUSPEND_ON)
709                 goto done;
710         if (!valid_state(test_state)) {
711                 printk(warn_bad_state, pm_states[test_state]);
712                 goto done;
713         }
714
715         /* RTCs have initialized by now too ... can we use one? */
716         class_find_device(rtc_class, NULL, &pony, has_wakealarm);
717         if (pony)
718                 rtc = rtc_class_open(pony);
719         if (!rtc) {
720                 printk(warn_no_rtc);
721                 goto done;
722         }
723
724         /* go for it */
725         test_wakealarm(rtc, test_state);
726         rtc_class_close(rtc);
727 done:
728         return 0;
729 }
730 late_initcall(test_suspend);
731
732 #endif /* CONFIG_PM_TEST_SUSPEND */