ftrace: disable tracing for suspend to ram
[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 #include <linux/ftrace.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 int suspend_test(int level)
61 {
62         if (pm_test_level == level) {
63                 printk(KERN_INFO "suspend debug: Waiting for 5 seconds.\n");
64                 mdelay(5000);
65                 return 1;
66         }
67         return 0;
68 }
69
70 static const char * const pm_tests[__TEST_AFTER_LAST] = {
71         [TEST_NONE] = "none",
72         [TEST_CORE] = "core",
73         [TEST_CPUS] = "processors",
74         [TEST_PLATFORM] = "platform",
75         [TEST_DEVICES] = "devices",
76         [TEST_FREEZER] = "freezer",
77 };
78
79 static ssize_t pm_test_show(struct kobject *kobj, struct kobj_attribute *attr,
80                                 char *buf)
81 {
82         char *s = buf;
83         int level;
84
85         for (level = TEST_FIRST; level <= TEST_MAX; level++)
86                 if (pm_tests[level]) {
87                         if (level == pm_test_level)
88                                 s += sprintf(s, "[%s] ", pm_tests[level]);
89                         else
90                                 s += sprintf(s, "%s ", pm_tests[level]);
91                 }
92
93         if (s != buf)
94                 /* convert the last space to a newline */
95                 *(s-1) = '\n';
96
97         return (s - buf);
98 }
99
100 static ssize_t pm_test_store(struct kobject *kobj, struct kobj_attribute *attr,
101                                 const char *buf, size_t n)
102 {
103         const char * const *s;
104         int level;
105         char *p;
106         int len;
107         int error = -EINVAL;
108
109         p = memchr(buf, '\n', n);
110         len = p ? p - buf : n;
111
112         mutex_lock(&pm_mutex);
113
114         level = TEST_FIRST;
115         for (s = &pm_tests[level]; level <= TEST_MAX; s++, level++)
116                 if (*s && len == strlen(*s) && !strncmp(buf, *s, len)) {
117                         pm_test_level = level;
118                         error = 0;
119                         break;
120                 }
121
122         mutex_unlock(&pm_mutex);
123
124         return error ? error : n;
125 }
126
127 power_attr(pm_test);
128 #else /* !CONFIG_PM_DEBUG */
129 static inline int suspend_test(int level) { return 0; }
130 #endif /* !CONFIG_PM_DEBUG */
131
132 #endif /* CONFIG_PM_SLEEP */
133
134 #ifdef CONFIG_SUSPEND
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_ON(msec > (TEST_SUSPEND_SECONDS * 1000));
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         if (suspend_freeze_processes()) {
241                 error = -EAGAIN;
242                 goto Thaw;
243         }
244
245         free_pages = global_page_state(NR_FREE_PAGES);
246         if (free_pages < FREE_PAGE_NUMBER) {
247                 pr_debug("PM: free some memory\n");
248                 shrink_all_memory(FREE_PAGE_NUMBER - free_pages);
249                 if (nr_free_pages() < FREE_PAGE_NUMBER) {
250                         error = -ENOMEM;
251                         printk(KERN_ERR "PM: No enough memory\n");
252                 }
253         }
254         if (!error)
255                 return 0;
256
257  Thaw:
258         suspend_thaw_processes();
259  Finish:
260         pm_notifier_call_chain(PM_POST_SUSPEND);
261         pm_restore_console();
262         return error;
263 }
264
265 /* default implementation */
266 void __attribute__ ((weak)) arch_suspend_disable_irqs(void)
267 {
268         local_irq_disable();
269 }
270
271 /* default implementation */
272 void __attribute__ ((weak)) arch_suspend_enable_irqs(void)
273 {
274         local_irq_enable();
275 }
276
277 /**
278  *      suspend_enter - enter the desired system sleep state.
279  *      @state:         state to enter
280  *
281  *      This function should be called after devices have been suspended.
282  */
283 static int suspend_enter(suspend_state_t state)
284 {
285         int error = 0;
286
287         device_pm_lock();
288         arch_suspend_disable_irqs();
289         BUG_ON(!irqs_disabled());
290
291         if ((error = device_power_down(PMSG_SUSPEND))) {
292                 printk(KERN_ERR "PM: Some devices failed to power down\n");
293                 goto Done;
294         }
295
296         if (!suspend_test(TEST_CORE))
297                 error = suspend_ops->enter(state);
298
299         device_power_up(PMSG_RESUME);
300  Done:
301         arch_suspend_enable_irqs();
302         BUG_ON(irqs_disabled());
303         device_pm_unlock();
304         return error;
305 }
306
307 /**
308  *      suspend_devices_and_enter - suspend devices and enter the desired system
309  *                                  sleep state.
310  *      @state:           state to enter
311  */
312 int suspend_devices_and_enter(suspend_state_t state)
313 {
314         int error, ftrace_save;
315
316         if (!suspend_ops)
317                 return -ENOSYS;
318
319         if (suspend_ops->begin) {
320                 error = suspend_ops->begin(state);
321                 if (error)
322                         goto Close;
323         }
324         suspend_console();
325         ftrace_save = __ftrace_enabled_save();
326         suspend_test_start();
327         error = device_suspend(PMSG_SUSPEND);
328         if (error) {
329                 printk(KERN_ERR "PM: Some devices failed to suspend\n");
330                 goto Recover_platform;
331         }
332         suspend_test_finish("suspend devices");
333         if (suspend_test(TEST_DEVICES))
334                 goto Recover_platform;
335
336         if (suspend_ops->prepare) {
337                 error = suspend_ops->prepare();
338                 if (error)
339                         goto Resume_devices;
340         }
341
342         if (suspend_test(TEST_PLATFORM))
343                 goto Finish;
344
345         error = disable_nonboot_cpus();
346         if (!error && !suspend_test(TEST_CPUS))
347                 suspend_enter(state);
348
349         enable_nonboot_cpus();
350  Finish:
351         if (suspend_ops->finish)
352                 suspend_ops->finish();
353  Resume_devices:
354         suspend_test_start();
355         device_resume(PMSG_RESUME);
356         suspend_test_finish("resume devices");
357         __ftrace_enabled_restore(ftrace_save);
358         resume_console();
359  Close:
360         if (suspend_ops->end)
361                 suspend_ops->end();
362         return error;
363
364  Recover_platform:
365         if (suspend_ops->recover)
366                 suspend_ops->recover();
367         goto Resume_devices;
368 }
369
370 /**
371  *      suspend_finish - Do final work before exiting suspend sequence.
372  *
373  *      Call platform code to clean up, restart processes, and free the 
374  *      console that we've allocated. This is not called for suspend-to-disk.
375  */
376 static void suspend_finish(void)
377 {
378         suspend_thaw_processes();
379         pm_notifier_call_chain(PM_POST_SUSPEND);
380         pm_restore_console();
381 }
382
383
384
385
386 static const char * const pm_states[PM_SUSPEND_MAX] = {
387         [PM_SUSPEND_STANDBY]    = "standby",
388         [PM_SUSPEND_MEM]        = "mem",
389 };
390
391 static inline int valid_state(suspend_state_t state)
392 {
393         /* All states need lowlevel support and need to be valid
394          * to the lowlevel implementation, no valid callback
395          * implies that none are valid. */
396         if (!suspend_ops || !suspend_ops->valid || !suspend_ops->valid(state))
397                 return 0;
398         return 1;
399 }
400
401
402 /**
403  *      enter_state - Do common work of entering low-power state.
404  *      @state:         pm_state structure for state we're entering.
405  *
406  *      Make sure we're the only ones trying to enter a sleep state. Fail
407  *      if someone has beat us to it, since we don't want anything weird to
408  *      happen when we wake up.
409  *      Then, do the setup for suspend, enter the state, and cleaup (after
410  *      we've woken up).
411  */
412 static int enter_state(suspend_state_t state)
413 {
414         int error;
415
416         if (!valid_state(state))
417                 return -ENODEV;
418
419         if (!mutex_trylock(&pm_mutex))
420                 return -EBUSY;
421
422         printk(KERN_INFO "PM: Syncing filesystems ... ");
423         sys_sync();
424         printk("done.\n");
425
426         pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]);
427         error = suspend_prepare();
428         if (error)
429                 goto Unlock;
430
431         if (suspend_test(TEST_FREEZER))
432                 goto Finish;
433
434         pr_debug("PM: Entering %s sleep\n", pm_states[state]);
435         error = suspend_devices_and_enter(state);
436
437  Finish:
438         pr_debug("PM: Finishing wakeup.\n");
439         suspend_finish();
440  Unlock:
441         mutex_unlock(&pm_mutex);
442         return error;
443 }
444
445
446 /**
447  *      pm_suspend - Externally visible function for suspending system.
448  *      @state:         Enumerated value of state to enter.
449  *
450  *      Determine whether or not value is within range, get state 
451  *      structure, and enter (above).
452  */
453
454 int pm_suspend(suspend_state_t state)
455 {
456         if (state > PM_SUSPEND_ON && state <= PM_SUSPEND_MAX)
457                 return enter_state(state);
458         return -EINVAL;
459 }
460
461 EXPORT_SYMBOL(pm_suspend);
462
463 #endif /* CONFIG_SUSPEND */
464
465 struct kobject *power_kobj;
466
467 /**
468  *      state - control system power state.
469  *
470  *      show() returns what states are supported, which is hard-coded to
471  *      'standby' (Power-On Suspend), 'mem' (Suspend-to-RAM), and
472  *      'disk' (Suspend-to-Disk).
473  *
474  *      store() accepts one of those strings, translates it into the 
475  *      proper enumerated value, and initiates a suspend transition.
476  */
477
478 static ssize_t state_show(struct kobject *kobj, struct kobj_attribute *attr,
479                           char *buf)
480 {
481         char *s = buf;
482 #ifdef CONFIG_SUSPEND
483         int i;
484
485         for (i = 0; i < PM_SUSPEND_MAX; i++) {
486                 if (pm_states[i] && valid_state(i))
487                         s += sprintf(s,"%s ", pm_states[i]);
488         }
489 #endif
490 #ifdef CONFIG_HIBERNATION
491         s += sprintf(s, "%s\n", "disk");
492 #else
493         if (s != buf)
494                 /* convert the last space to a newline */
495                 *(s-1) = '\n';
496 #endif
497         return (s - buf);
498 }
499
500 static ssize_t state_store(struct kobject *kobj, struct kobj_attribute *attr,
501                            const char *buf, size_t n)
502 {
503 #ifdef CONFIG_SUSPEND
504         suspend_state_t state = PM_SUSPEND_STANDBY;
505         const char * const *s;
506 #endif
507         char *p;
508         int len;
509         int error = -EINVAL;
510
511         p = memchr(buf, '\n', n);
512         len = p ? p - buf : n;
513
514         /* First, check if we are requested to hibernate */
515         if (len == 4 && !strncmp(buf, "disk", len)) {
516                 error = hibernate();
517   goto Exit;
518         }
519
520 #ifdef CONFIG_SUSPEND
521         for (s = &pm_states[state]; state < PM_SUSPEND_MAX; s++, state++) {
522                 if (*s && len == strlen(*s) && !strncmp(buf, *s, len))
523                         break;
524         }
525         if (state < PM_SUSPEND_MAX && *s)
526                 error = enter_state(state);
527 #endif
528
529  Exit:
530         return error ? error : n;
531 }
532
533 power_attr(state);
534
535 #ifdef CONFIG_PM_TRACE
536 int pm_trace_enabled;
537
538 static ssize_t pm_trace_show(struct kobject *kobj, struct kobj_attribute *attr,
539                              char *buf)
540 {
541         return sprintf(buf, "%d\n", pm_trace_enabled);
542 }
543
544 static ssize_t
545 pm_trace_store(struct kobject *kobj, struct kobj_attribute *attr,
546                const char *buf, size_t n)
547 {
548         int val;
549
550         if (sscanf(buf, "%d", &val) == 1) {
551                 pm_trace_enabled = !!val;
552                 return n;
553         }
554         return -EINVAL;
555 }
556
557 power_attr(pm_trace);
558 #endif /* CONFIG_PM_TRACE */
559
560 static struct attribute * g[] = {
561         &state_attr.attr,
562 #ifdef CONFIG_PM_TRACE
563         &pm_trace_attr.attr,
564 #endif
565 #if defined(CONFIG_PM_SLEEP) && defined(CONFIG_PM_DEBUG)
566         &pm_test_attr.attr,
567 #endif
568         NULL,
569 };
570
571 static struct attribute_group attr_group = {
572         .attrs = g,
573 };
574
575
576 static int __init pm_init(void)
577 {
578         power_kobj = kobject_create_and_add("power", NULL);
579         if (!power_kobj)
580                 return -ENOMEM;
581         return sysfs_create_group(power_kobj, &attr_group);
582 }
583
584 core_initcall(pm_init);
585
586
587 #ifdef CONFIG_PM_TEST_SUSPEND
588
589 #include <linux/rtc.h>
590
591 /*
592  * To test system suspend, we need a hands-off mechanism to resume the
593  * system.  RTCs wake alarms are a common self-contained mechanism.
594  */
595
596 static void __init test_wakealarm(struct rtc_device *rtc, suspend_state_t state)
597 {
598         static char err_readtime[] __initdata =
599                 KERN_ERR "PM: can't read %s time, err %d\n";
600         static char err_wakealarm [] __initdata =
601                 KERN_ERR "PM: can't set %s wakealarm, err %d\n";
602         static char err_suspend[] __initdata =
603                 KERN_ERR "PM: suspend test failed, error %d\n";
604         static char info_test[] __initdata =
605                 KERN_INFO "PM: test RTC wakeup from '%s' suspend\n";
606
607         unsigned long           now;
608         struct rtc_wkalrm       alm;
609         int                     status;
610
611         /* this may fail if the RTC hasn't been initialized */
612         status = rtc_read_time(rtc, &alm.time);
613         if (status < 0) {
614                 printk(err_readtime, rtc->dev.bus_id, status);
615                 return;
616         }
617         rtc_tm_to_time(&alm.time, &now);
618
619         memset(&alm, 0, sizeof alm);
620         rtc_time_to_tm(now + TEST_SUSPEND_SECONDS, &alm.time);
621         alm.enabled = true;
622
623         status = rtc_set_alarm(rtc, &alm);
624         if (status < 0) {
625                 printk(err_wakealarm, rtc->dev.bus_id, status);
626                 return;
627         }
628
629         if (state == PM_SUSPEND_MEM) {
630                 printk(info_test, pm_states[state]);
631                 status = pm_suspend(state);
632                 if (status == -ENODEV)
633                         state = PM_SUSPEND_STANDBY;
634         }
635         if (state == PM_SUSPEND_STANDBY) {
636                 printk(info_test, pm_states[state]);
637                 status = pm_suspend(state);
638         }
639         if (status < 0)
640                 printk(err_suspend, status);
641
642         /* Some platforms can't detect that the alarm triggered the
643          * wakeup, or (accordingly) disable it after it afterwards.
644          * It's supposed to give oneshot behavior; cope.
645          */
646         alm.enabled = false;
647         rtc_set_alarm(rtc, &alm);
648 }
649
650 static int __init has_wakealarm(struct device *dev, void *name_ptr)
651 {
652         struct rtc_device *candidate = to_rtc_device(dev);
653
654         if (!candidate->ops->set_alarm)
655                 return 0;
656         if (!device_may_wakeup(candidate->dev.parent))
657                 return 0;
658
659         *(char **)name_ptr = dev->bus_id;
660         return 1;
661 }
662
663 /*
664  * Kernel options like "test_suspend=mem" force suspend/resume sanity tests
665  * at startup time.  They're normally disabled, for faster boot and because
666  * we can't know which states really work on this particular system.
667  */
668 static suspend_state_t test_state __initdata = PM_SUSPEND_ON;
669
670 static char warn_bad_state[] __initdata =
671         KERN_WARNING "PM: can't test '%s' suspend state\n";
672
673 static int __init setup_test_suspend(char *value)
674 {
675         unsigned i;
676
677         /* "=mem" ==> "mem" */
678         value++;
679         for (i = 0; i < PM_SUSPEND_MAX; i++) {
680                 if (!pm_states[i])
681                         continue;
682                 if (strcmp(pm_states[i], value) != 0)
683                         continue;
684                 test_state = (__force suspend_state_t) i;
685                 return 0;
686         }
687         printk(warn_bad_state, value);
688         return 0;
689 }
690 __setup("test_suspend", setup_test_suspend);
691
692 static int __init test_suspend(void)
693 {
694         static char             warn_no_rtc[] __initdata =
695                 KERN_WARNING "PM: no wakealarm-capable RTC driver is ready\n";
696
697         char                    *pony = NULL;
698         struct rtc_device       *rtc = NULL;
699
700         /* PM is initialized by now; is that state testable? */
701         if (test_state == PM_SUSPEND_ON)
702                 goto done;
703         if (!valid_state(test_state)) {
704                 printk(warn_bad_state, pm_states[test_state]);
705                 goto done;
706         }
707
708         /* RTCs have initialized by now too ... can we use one? */
709         class_find_device(rtc_class, NULL, &pony, has_wakealarm);
710         if (pony)
711                 rtc = rtc_class_open(pony);
712         if (!rtc) {
713                 printk(warn_no_rtc);
714                 goto done;
715         }
716
717         /* go for it */
718         test_wakealarm(rtc, test_state);
719         rtc_class_close(rtc);
720 done:
721         return 0;
722 }
723 late_initcall(test_suspend);
724
725 #endif /* CONFIG_PM_TEST_SUSPEND */