0b7476f5d2a64fc848b88bfc51a06eb8d233eae1
[linux-2.6.git] / 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/init.h>
18 #include <linux/console.h>
19 #include <linux/cpu.h>
20 #include <linux/resume-trace.h>
21 #include <linux/freezer.h>
22 #include <linux/vmstat.h>
23 #include <linux/syscalls.h>
24
25 #include "power.h"
26
27 DEFINE_MUTEX(pm_mutex);
28
29 unsigned int pm_flags;
30 EXPORT_SYMBOL(pm_flags);
31
32 #ifdef CONFIG_PM_SLEEP
33
34 /* Routines for PM-transition notifications */
35
36 static BLOCKING_NOTIFIER_HEAD(pm_chain_head);
37
38 int register_pm_notifier(struct notifier_block *nb)
39 {
40         return blocking_notifier_chain_register(&pm_chain_head, nb);
41 }
42 EXPORT_SYMBOL_GPL(register_pm_notifier);
43
44 int unregister_pm_notifier(struct notifier_block *nb)
45 {
46         return blocking_notifier_chain_unregister(&pm_chain_head, nb);
47 }
48 EXPORT_SYMBOL_GPL(unregister_pm_notifier);
49
50 int pm_notifier_call_chain(unsigned long val)
51 {
52         return (blocking_notifier_call_chain(&pm_chain_head, val, NULL)
53                         == NOTIFY_BAD) ? -EINVAL : 0;
54 }
55
56 #ifdef CONFIG_PM_DEBUG
57 int pm_test_level = TEST_NONE;
58
59 static int suspend_test(int level)
60 {
61         if (pm_test_level == level) {
62                 printk(KERN_INFO "suspend debug: Waiting for 5 seconds.\n");
63                 mdelay(5000);
64                 return 1;
65         }
66         return 0;
67 }
68
69 static const char * const pm_tests[__TEST_AFTER_LAST] = {
70         [TEST_NONE] = "none",
71         [TEST_CORE] = "core",
72         [TEST_CPUS] = "processors",
73         [TEST_PLATFORM] = "platform",
74         [TEST_DEVICES] = "devices",
75         [TEST_FREEZER] = "freezer",
76 };
77
78 static ssize_t pm_test_show(struct kobject *kobj, struct kobj_attribute *attr,
79                                 char *buf)
80 {
81         char *s = buf;
82         int level;
83
84         for (level = TEST_FIRST; level <= TEST_MAX; level++)
85                 if (pm_tests[level]) {
86                         if (level == pm_test_level)
87                                 s += sprintf(s, "[%s] ", pm_tests[level]);
88                         else
89                                 s += sprintf(s, "%s ", pm_tests[level]);
90                 }
91
92         if (s != buf)
93                 /* convert the last space to a newline */
94                 *(s-1) = '\n';
95
96         return (s - buf);
97 }
98
99 static ssize_t pm_test_store(struct kobject *kobj, struct kobj_attribute *attr,
100                                 const char *buf, size_t n)
101 {
102         const char * const *s;
103         int level;
104         char *p;
105         int len;
106         int error = -EINVAL;
107
108         p = memchr(buf, '\n', n);
109         len = p ? p - buf : n;
110
111         mutex_lock(&pm_mutex);
112
113         level = TEST_FIRST;
114         for (s = &pm_tests[level]; level <= TEST_MAX; s++, level++)
115                 if (*s && len == strlen(*s) && !strncmp(buf, *s, len)) {
116                         pm_test_level = level;
117                         error = 0;
118                         break;
119                 }
120
121         mutex_unlock(&pm_mutex);
122
123         return error ? error : n;
124 }
125
126 power_attr(pm_test);
127 #else /* !CONFIG_PM_DEBUG */
128 static inline int suspend_test(int level) { return 0; }
129 #endif /* !CONFIG_PM_DEBUG */
130
131 #endif /* CONFIG_PM_SLEEP */
132
133 #ifdef CONFIG_SUSPEND
134
135 #ifdef CONFIG_PM_TEST_SUSPEND
136
137 /*
138  * We test the system suspend code by setting an RTC wakealarm a short
139  * time in the future, then suspending.  Suspending the devices won't
140  * normally take long ... some systems only need a few milliseconds.
141  *
142  * The time it takes is system-specific though, so when we test this
143  * during system bootup we allow a LOT of time.
144  */
145 #define TEST_SUSPEND_SECONDS    5
146
147 static unsigned long suspend_test_start_time;
148
149 static void suspend_test_start(void)
150 {
151         /* FIXME Use better timebase than "jiffies", ideally a clocksource.
152          * What we want is a hardware counter that will work correctly even
153          * during the irqs-are-off stages of the suspend/resume cycle...
154          */
155         suspend_test_start_time = jiffies;
156 }
157
158 static void suspend_test_finish(const char *label)
159 {
160         long nj = jiffies - suspend_test_start_time;
161         unsigned msec;
162
163         msec = jiffies_to_msecs(abs(nj));
164         pr_info("PM: %s took %d.%03d seconds\n", label,
165                         msec / 1000, msec % 1000);
166
167         /* Warning on suspend means the RTC alarm period needs to be
168          * larger -- the system was sooo slooowwww to suspend that the
169          * alarm (should have) fired before the system went to sleep!
170          *
171          * Warning on either suspend or resume also means the system
172          * has some performance issues.  The stack dump of a WARN_ON
173          * is more likely to get the right attention than a printk...
174          */
175         WARN_ON(msec > (TEST_SUSPEND_SECONDS * 1000));
176 }
177
178 #else
179
180 static void suspend_test_start(void)
181 {
182 }
183
184 static void suspend_test_finish(const char *label)
185 {
186 }
187
188 #endif
189
190 /* This is just an arbitrary number */
191 #define FREE_PAGE_NUMBER (100)
192
193 static struct platform_suspend_ops *suspend_ops;
194
195 /**
196  *      suspend_set_ops - Set the global suspend method table.
197  *      @ops:   Pointer to ops structure.
198  */
199
200 void suspend_set_ops(struct platform_suspend_ops *ops)
201 {
202         mutex_lock(&pm_mutex);
203         suspend_ops = ops;
204         mutex_unlock(&pm_mutex);
205 }
206
207 /**
208  * suspend_valid_only_mem - generic memory-only valid callback
209  *
210  * Platform drivers that implement mem suspend only and only need
211  * to check for that in their .valid callback can use this instead
212  * of rolling their own .valid callback.
213  */
214 int suspend_valid_only_mem(suspend_state_t state)
215 {
216         return state == PM_SUSPEND_MEM;
217 }
218
219 /**
220  *      suspend_prepare - Do prep work before entering low-power state.
221  *
222  *      This is common code that is called for each state that we're entering.
223  *      Run suspend notifiers, allocate a console and stop all processes.
224  */
225 static int suspend_prepare(void)
226 {
227         int error;
228         unsigned int free_pages;
229
230         if (!suspend_ops || !suspend_ops->enter)
231                 return -EPERM;
232
233         pm_prepare_console();
234
235         error = pm_notifier_call_chain(PM_SUSPEND_PREPARE);
236         if (error)
237                 goto Finish;
238
239         if (suspend_freeze_processes()) {
240                 error = -EAGAIN;
241                 goto Thaw;
242         }
243
244         free_pages = global_page_state(NR_FREE_PAGES);
245         if (free_pages < FREE_PAGE_NUMBER) {
246                 pr_debug("PM: free some memory\n");
247                 shrink_all_memory(FREE_PAGE_NUMBER - free_pages);
248                 if (nr_free_pages() < FREE_PAGE_NUMBER) {
249                         error = -ENOMEM;
250                         printk(KERN_ERR "PM: No enough memory\n");
251                 }
252         }
253         if (!error)
254                 return 0;
255
256  Thaw:
257         suspend_thaw_processes();
258  Finish:
259         pm_notifier_call_chain(PM_POST_SUSPEND);
260         pm_restore_console();
261         return error;
262 }
263
264 /* default implementation */
265 void __attribute__ ((weak)) arch_suspend_disable_irqs(void)
266 {
267         local_irq_disable();
268 }
269
270 /* default implementation */
271 void __attribute__ ((weak)) arch_suspend_enable_irqs(void)
272 {
273         local_irq_enable();
274 }
275
276 /**
277  *      suspend_enter - enter the desired system sleep state.
278  *      @state:         state to enter
279  *
280  *      This function should be called after devices have been suspended.
281  */
282 static int suspend_enter(suspend_state_t state)
283 {
284         int error = 0;
285
286         device_pm_lock();
287         arch_suspend_disable_irqs();
288         BUG_ON(!irqs_disabled());
289
290         if ((error = device_power_down(PMSG_SUSPEND))) {
291                 printk(KERN_ERR "PM: Some devices failed to power down\n");
292                 goto Done;
293         }
294
295         if (!suspend_test(TEST_CORE))
296                 error = suspend_ops->enter(state);
297
298         device_power_up(PMSG_RESUME);
299  Done:
300         arch_suspend_enable_irqs();
301         BUG_ON(irqs_disabled());
302         device_pm_unlock();
303         return error;
304 }
305
306 /**
307  *      suspend_devices_and_enter - suspend devices and enter the desired system
308  *                                  sleep state.
309  *      @state:           state to enter
310  */
311 int suspend_devices_and_enter(suspend_state_t state)
312 {
313         int error;
314
315         if (!suspend_ops)
316                 return -ENOSYS;
317
318         if (suspend_ops->begin) {
319                 error = suspend_ops->begin(state);
320                 if (error)
321                         goto Close;
322         }
323         suspend_console();
324         suspend_test_start();
325         error = device_suspend(PMSG_SUSPEND);
326         if (error) {
327                 printk(KERN_ERR "PM: Some devices failed to suspend\n");
328                 goto Recover_platform;
329         }
330         suspend_test_finish("suspend devices");
331         if (suspend_test(TEST_DEVICES))
332                 goto Recover_platform;
333
334         if (suspend_ops->prepare) {
335                 error = suspend_ops->prepare();
336                 if (error)
337                         goto Resume_devices;
338         }
339
340         if (suspend_test(TEST_PLATFORM))
341                 goto Finish;
342
343         error = disable_nonboot_cpus();
344         if (!error && !suspend_test(TEST_CPUS))
345                 suspend_enter(state);
346
347         enable_nonboot_cpus();
348  Finish:
349         if (suspend_ops->finish)
350                 suspend_ops->finish();
351  Resume_devices:
352         suspend_test_start();
353         device_resume(PMSG_RESUME);
354         suspend_test_finish("resume devices");
355         resume_console();
356  Close:
357         if (suspend_ops->end)
358                 suspend_ops->end();
359         return error;
360
361  Recover_platform:
362         if (suspend_ops->recover)
363                 suspend_ops->recover();
364         goto Resume_devices;
365 }
366
367 /**
368  *      suspend_finish - Do final work before exiting suspend sequence.
369  *
370  *      Call platform code to clean up, restart processes, and free the 
371  *      console that we've allocated. This is not called for suspend-to-disk.
372  */
373 static void suspend_finish(void)
374 {
375         suspend_thaw_processes();
376         pm_notifier_call_chain(PM_POST_SUSPEND);
377         pm_restore_console();
378 }
379
380
381
382
383 static const char * const pm_states[PM_SUSPEND_MAX] = {
384         [PM_SUSPEND_STANDBY]    = "standby",
385         [PM_SUSPEND_MEM]        = "mem",
386 };
387
388 static inline int valid_state(suspend_state_t state)
389 {
390         /* All states need lowlevel support and need to be valid
391          * to the lowlevel implementation, no valid callback
392          * implies that none are valid. */
393         if (!suspend_ops || !suspend_ops->valid || !suspend_ops->valid(state))
394                 return 0;
395         return 1;
396 }
397
398
399 /**
400  *      enter_state - Do common work of entering low-power state.
401  *      @state:         pm_state structure for state we're entering.
402  *
403  *      Make sure we're the only ones trying to enter a sleep state. Fail
404  *      if someone has beat us to it, since we don't want anything weird to
405  *      happen when we wake up.
406  *      Then, do the setup for suspend, enter the state, and cleaup (after
407  *      we've woken up).
408  */
409 static int enter_state(suspend_state_t state)
410 {
411         int error;
412
413         if (!valid_state(state))
414                 return -ENODEV;
415
416         if (!mutex_trylock(&pm_mutex))
417                 return -EBUSY;
418
419         printk(KERN_INFO "PM: Syncing filesystems ... ");
420         sys_sync();
421         printk("done.\n");
422
423         pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]);
424         error = suspend_prepare();
425         if (error)
426                 goto Unlock;
427
428         if (suspend_test(TEST_FREEZER))
429                 goto Finish;
430
431         pr_debug("PM: Entering %s sleep\n", pm_states[state]);
432         error = suspend_devices_and_enter(state);
433
434  Finish:
435         pr_debug("PM: Finishing wakeup.\n");
436         suspend_finish();
437  Unlock:
438         mutex_unlock(&pm_mutex);
439         return error;
440 }
441
442
443 /**
444  *      pm_suspend - Externally visible function for suspending system.
445  *      @state:         Enumerated value of state to enter.
446  *
447  *      Determine whether or not value is within range, get state 
448  *      structure, and enter (above).
449  */
450
451 int pm_suspend(suspend_state_t state)
452 {
453         if (state > PM_SUSPEND_ON && state <= PM_SUSPEND_MAX)
454                 return enter_state(state);
455         return -EINVAL;
456 }
457
458 EXPORT_SYMBOL(pm_suspend);
459
460 #endif /* CONFIG_SUSPEND */
461
462 struct kobject *power_kobj;
463
464 /**
465  *      state - control system power state.
466  *
467  *      show() returns what states are supported, which is hard-coded to
468  *      'standby' (Power-On Suspend), 'mem' (Suspend-to-RAM), and
469  *      'disk' (Suspend-to-Disk).
470  *
471  *      store() accepts one of those strings, translates it into the 
472  *      proper enumerated value, and initiates a suspend transition.
473  */
474
475 static ssize_t state_show(struct kobject *kobj, struct kobj_attribute *attr,
476                           char *buf)
477 {
478         char *s = buf;
479 #ifdef CONFIG_SUSPEND
480         int i;
481
482         for (i = 0; i < PM_SUSPEND_MAX; i++) {
483                 if (pm_states[i] && valid_state(i))
484                         s += sprintf(s,"%s ", pm_states[i]);
485         }
486 #endif
487 #ifdef CONFIG_HIBERNATION
488         s += sprintf(s, "%s\n", "disk");
489 #else
490         if (s != buf)
491                 /* convert the last space to a newline */
492                 *(s-1) = '\n';
493 #endif
494         return (s - buf);
495 }
496
497 static ssize_t state_store(struct kobject *kobj, struct kobj_attribute *attr,
498                            const char *buf, size_t n)
499 {
500 #ifdef CONFIG_SUSPEND
501         suspend_state_t state = PM_SUSPEND_STANDBY;
502         const char * const *s;
503 #endif
504         char *p;
505         int len;
506         int error = -EINVAL;
507
508         p = memchr(buf, '\n', n);
509         len = p ? p - buf : n;
510
511         /* First, check if we are requested to hibernate */
512         if (len == 4 && !strncmp(buf, "disk", len)) {
513                 error = hibernate();
514   goto Exit;
515         }
516
517 #ifdef CONFIG_SUSPEND
518         for (s = &pm_states[state]; state < PM_SUSPEND_MAX; s++, state++) {
519                 if (*s && len == strlen(*s) && !strncmp(buf, *s, len))
520                         break;
521         }
522         if (state < PM_SUSPEND_MAX && *s)
523                 error = enter_state(state);
524 #endif
525
526  Exit:
527         return error ? error : n;
528 }
529
530 power_attr(state);
531
532 #ifdef CONFIG_PM_TRACE
533 int pm_trace_enabled;
534
535 static ssize_t pm_trace_show(struct kobject *kobj, struct kobj_attribute *attr,
536                              char *buf)
537 {
538         return sprintf(buf, "%d\n", pm_trace_enabled);
539 }
540
541 static ssize_t
542 pm_trace_store(struct kobject *kobj, struct kobj_attribute *attr,
543                const char *buf, size_t n)
544 {
545         int val;
546
547         if (sscanf(buf, "%d", &val) == 1) {
548                 pm_trace_enabled = !!val;
549                 return n;
550         }
551         return -EINVAL;
552 }
553
554 power_attr(pm_trace);
555 #endif /* CONFIG_PM_TRACE */
556
557 static struct attribute * g[] = {
558         &state_attr.attr,
559 #ifdef CONFIG_PM_TRACE
560         &pm_trace_attr.attr,
561 #endif
562 #if defined(CONFIG_PM_SLEEP) && defined(CONFIG_PM_DEBUG)
563         &pm_test_attr.attr,
564 #endif
565         NULL,
566 };
567
568 static struct attribute_group attr_group = {
569         .attrs = g,
570 };
571
572
573 static int __init pm_init(void)
574 {
575         power_kobj = kobject_create_and_add("power", NULL);
576         if (!power_kobj)
577                 return -ENOMEM;
578         return sysfs_create_group(power_kobj, &attr_group);
579 }
580
581 core_initcall(pm_init);
582
583
584 #ifdef CONFIG_PM_TEST_SUSPEND
585
586 #include <linux/rtc.h>
587
588 /*
589  * To test system suspend, we need a hands-off mechanism to resume the
590  * system.  RTCs wake alarms are a common self-contained mechanism.
591  */
592
593 static void __init test_wakealarm(struct rtc_device *rtc, suspend_state_t state)
594 {
595         static char err_readtime[] __initdata =
596                 KERN_ERR "PM: can't read %s time, err %d\n";
597         static char err_wakealarm [] __initdata =
598                 KERN_ERR "PM: can't set %s wakealarm, err %d\n";
599         static char err_suspend[] __initdata =
600                 KERN_ERR "PM: suspend test failed, error %d\n";
601         static char info_test[] __initdata =
602                 KERN_INFO "PM: test RTC wakeup from '%s' suspend\n";
603
604         unsigned long           now;
605         struct rtc_wkalrm       alm;
606         int                     status;
607
608         /* this may fail if the RTC hasn't been initialized */
609         status = rtc_read_time(rtc, &alm.time);
610         if (status < 0) {
611                 printk(err_readtime, rtc->dev.bus_id, status);
612                 return;
613         }
614         rtc_tm_to_time(&alm.time, &now);
615
616         memset(&alm, 0, sizeof alm);
617         rtc_time_to_tm(now + TEST_SUSPEND_SECONDS, &alm.time);
618         alm.enabled = true;
619
620         status = rtc_set_alarm(rtc, &alm);
621         if (status < 0) {
622                 printk(err_wakealarm, rtc->dev.bus_id, status);
623                 return;
624         }
625
626         if (state == PM_SUSPEND_MEM) {
627                 printk(info_test, pm_states[state]);
628                 status = pm_suspend(state);
629                 if (status == -ENODEV)
630                         state = PM_SUSPEND_STANDBY;
631         }
632         if (state == PM_SUSPEND_STANDBY) {
633                 printk(info_test, pm_states[state]);
634                 status = pm_suspend(state);
635         }
636         if (status < 0)
637                 printk(err_suspend, status);
638
639         /* Some platforms can't detect that the alarm triggered the
640          * wakeup, or (accordingly) disable it after it afterwards.
641          * It's supposed to give oneshot behavior; cope.
642          */
643         alm.enabled = false;
644         rtc_set_alarm(rtc, &alm);
645 }
646
647 static int __init has_wakealarm(struct device *dev, void *name_ptr)
648 {
649         struct rtc_device *candidate = to_rtc_device(dev);
650
651         if (!candidate->ops->set_alarm)
652                 return 0;
653         if (!device_may_wakeup(candidate->dev.parent))
654                 return 0;
655
656         *(char **)name_ptr = dev->bus_id;
657         return 1;
658 }
659
660 /*
661  * Kernel options like "test_suspend=mem" force suspend/resume sanity tests
662  * at startup time.  They're normally disabled, for faster boot and because
663  * we can't know which states really work on this particular system.
664  */
665 static suspend_state_t test_state __initdata = PM_SUSPEND_ON;
666
667 static char warn_bad_state[] __initdata =
668         KERN_WARNING "PM: can't test '%s' suspend state\n";
669
670 static int __init setup_test_suspend(char *value)
671 {
672         unsigned i;
673
674         /* "=mem" ==> "mem" */
675         value++;
676         for (i = 0; i < PM_SUSPEND_MAX; i++) {
677                 if (!pm_states[i])
678                         continue;
679                 if (strcmp(pm_states[i], value) != 0)
680                         continue;
681                 test_state = (__force suspend_state_t) i;
682                 return 0;
683         }
684         printk(warn_bad_state, value);
685         return 0;
686 }
687 __setup("test_suspend", setup_test_suspend);
688
689 static int __init test_suspend(void)
690 {
691         static char             warn_no_rtc[] __initdata =
692                 KERN_WARNING "PM: no wakealarm-capable RTC driver is ready\n";
693
694         char                    *pony = NULL;
695         struct rtc_device       *rtc = NULL;
696
697         /* PM is initialized by now; is that state testable? */
698         if (test_state == PM_SUSPEND_ON)
699                 goto done;
700         if (!valid_state(test_state)) {
701                 printk(warn_bad_state, pm_states[test_state]);
702                 goto done;
703         }
704
705         /* RTCs have initialized by now too ... can we use one? */
706         class_find_device(rtc_class, NULL, &pony, has_wakealarm);
707         if (pony)
708                 rtc = rtc_class_open(pony);
709         if (!rtc) {
710                 printk(warn_no_rtc);
711                 goto done;
712         }
713
714         /* go for it */
715         test_wakealarm(rtc, test_state);
716         rtc_class_close(rtc);
717 done:
718         return 0;
719 }
720 late_initcall(test_suspend);
721
722 #endif /* CONFIG_PM_TEST_SUSPEND */