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