2 * kernel/power/main.c - PM subsystem core functionality.
4 * Copyright (c) 2003 Patrick Mochel
5 * Copyright (c) 2003 Open Source Development Lab
7 * This file is released under the GPLv2
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>
28 DEFINE_MUTEX(pm_mutex
);
30 unsigned int pm_flags
;
31 EXPORT_SYMBOL(pm_flags
);
33 #ifdef CONFIG_PM_SLEEP
35 /* Routines for PM-transition notifications */
37 static BLOCKING_NOTIFIER_HEAD(pm_chain_head
);
39 int register_pm_notifier(struct notifier_block
*nb
)
41 return blocking_notifier_chain_register(&pm_chain_head
, nb
);
43 EXPORT_SYMBOL_GPL(register_pm_notifier
);
45 int unregister_pm_notifier(struct notifier_block
*nb
)
47 return blocking_notifier_chain_unregister(&pm_chain_head
, nb
);
49 EXPORT_SYMBOL_GPL(unregister_pm_notifier
);
51 int pm_notifier_call_chain(unsigned long val
)
53 return (blocking_notifier_call_chain(&pm_chain_head
, val
, NULL
)
54 == NOTIFY_BAD
) ? -EINVAL
: 0;
57 #ifdef CONFIG_PM_DEBUG
58 int pm_test_level
= TEST_NONE
;
60 static const char * const pm_tests
[__TEST_AFTER_LAST
] = {
63 [TEST_CPUS
] = "processors",
64 [TEST_PLATFORM
] = "platform",
65 [TEST_DEVICES
] = "devices",
66 [TEST_FREEZER
] = "freezer",
69 static ssize_t
pm_test_show(struct kobject
*kobj
, struct kobj_attribute
*attr
,
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
]);
80 s
+= sprintf(s
, "%s ", pm_tests
[level
]);
84 /* convert the last space to a newline */
90 static ssize_t
pm_test_store(struct kobject
*kobj
, struct kobj_attribute
*attr
,
91 const char *buf
, size_t n
)
93 const char * const *s
;
99 p
= memchr(buf
, '\n', n
);
100 len
= p
? p
- buf
: n
;
102 mutex_lock(&pm_mutex
);
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
;
112 mutex_unlock(&pm_mutex
);
114 return error
? error
: n
;
118 #endif /* CONFIG_PM_DEBUG */
120 #endif /* CONFIG_PM_SLEEP */
122 #ifdef CONFIG_SUSPEND
124 static int suspend_test(int level
)
126 #ifdef CONFIG_PM_DEBUG
127 if (pm_test_level
== level
) {
128 printk(KERN_INFO
"suspend debug: Waiting for 5 seconds.\n");
132 #endif /* !CONFIG_PM_DEBUG */
136 #ifdef CONFIG_PM_TEST_SUSPEND
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.
143 * The time it takes is system-specific though, so when we test this
144 * during system bootup we allow a LOT of time.
146 #define TEST_SUSPEND_SECONDS 5
148 static unsigned long suspend_test_start_time
;
150 static void suspend_test_start(void)
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...
156 suspend_test_start_time
= jiffies
;
159 static void suspend_test_finish(const char *label
)
161 long nj
= jiffies
- suspend_test_start_time
;
164 msec
= jiffies_to_msecs(abs(nj
));
165 pr_info("PM: %s took %d.%03d seconds\n", label
,
166 msec
/ 1000, msec
% 1000);
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!
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...
176 WARN(msec
> (TEST_SUSPEND_SECONDS
* 1000), "Component: %s\n", label
);
181 static void suspend_test_start(void)
185 static void suspend_test_finish(const char *label
)
191 /* This is just an arbitrary number */
192 #define FREE_PAGE_NUMBER (100)
194 static struct platform_suspend_ops
*suspend_ops
;
197 * suspend_set_ops - Set the global suspend method table.
198 * @ops: Pointer to ops structure.
201 void suspend_set_ops(struct platform_suspend_ops
*ops
)
203 mutex_lock(&pm_mutex
);
205 mutex_unlock(&pm_mutex
);
209 * suspend_valid_only_mem - generic memory-only valid callback
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.
215 int suspend_valid_only_mem(suspend_state_t state
)
217 return state
== PM_SUSPEND_MEM
;
221 * suspend_prepare - Do prep work before entering low-power state.
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.
226 static int suspend_prepare(void)
229 unsigned int free_pages
;
231 if (!suspend_ops
|| !suspend_ops
->enter
)
234 pm_prepare_console();
236 error
= pm_notifier_call_chain(PM_SUSPEND_PREPARE
);
240 error
= usermodehelper_disable();
244 if (suspend_freeze_processes()) {
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
) {
255 printk(KERN_ERR
"PM: No enough memory\n");
262 suspend_thaw_processes();
263 usermodehelper_enable();
265 pm_notifier_call_chain(PM_POST_SUSPEND
);
266 pm_restore_console();
270 /* default implementation */
271 void __attribute__ ((weak
)) arch_suspend_disable_irqs(void)
276 /* default implementation */
277 void __attribute__ ((weak
)) arch_suspend_enable_irqs(void)
283 * suspend_enter - enter the desired system sleep state.
284 * @state: state to enter
286 * This function should be called after devices have been suspended.
288 static int suspend_enter(suspend_state_t state
)
293 arch_suspend_disable_irqs();
294 BUG_ON(!irqs_disabled());
296 if ((error
= device_power_down(PMSG_SUSPEND
))) {
297 printk(KERN_ERR
"PM: Some devices failed to power down\n");
301 error
= sysdev_suspend(PMSG_SUSPEND
);
303 if (!suspend_test(TEST_CORE
))
304 error
= suspend_ops
->enter(state
);
308 device_power_up(PMSG_RESUME
);
310 arch_suspend_enable_irqs();
311 BUG_ON(irqs_disabled());
317 * suspend_devices_and_enter - suspend devices and enter the desired system
319 * @state: state to enter
321 int suspend_devices_and_enter(suspend_state_t state
)
328 if (suspend_ops
->begin
) {
329 error
= suspend_ops
->begin(state
);
334 suspend_test_start();
335 error
= device_suspend(PMSG_SUSPEND
);
337 printk(KERN_ERR
"PM: Some devices failed to suspend\n");
338 goto Recover_platform
;
340 suspend_test_finish("suspend devices");
341 if (suspend_test(TEST_DEVICES
))
342 goto Recover_platform
;
344 if (suspend_ops
->prepare
) {
345 error
= suspend_ops
->prepare();
350 if (suspend_test(TEST_PLATFORM
))
353 error
= disable_nonboot_cpus();
354 if (!error
&& !suspend_test(TEST_CPUS
))
355 suspend_enter(state
);
357 enable_nonboot_cpus();
359 if (suspend_ops
->finish
)
360 suspend_ops
->finish();
362 suspend_test_start();
363 device_resume(PMSG_RESUME
);
364 suspend_test_finish("resume devices");
367 if (suspend_ops
->end
)
372 if (suspend_ops
->recover
)
373 suspend_ops
->recover();
378 * suspend_finish - Do final work before exiting suspend sequence.
380 * Call platform code to clean up, restart processes, and free the
381 * console that we've allocated. This is not called for suspend-to-disk.
383 static void suspend_finish(void)
385 suspend_thaw_processes();
386 usermodehelper_enable();
387 pm_notifier_call_chain(PM_POST_SUSPEND
);
388 pm_restore_console();
394 static const char * const pm_states
[PM_SUSPEND_MAX
] = {
395 [PM_SUSPEND_STANDBY
] = "standby",
396 [PM_SUSPEND_MEM
] = "mem",
399 static inline int valid_state(suspend_state_t state
)
401 /* All states need lowlevel support and need to be valid
402 * to the lowlevel implementation, no valid callback
403 * implies that none are valid. */
404 if (!suspend_ops
|| !suspend_ops
->valid
|| !suspend_ops
->valid(state
))
411 * enter_state - Do common work of entering low-power state.
412 * @state: pm_state structure for state we're entering.
414 * Make sure we're the only ones trying to enter a sleep state. Fail
415 * if someone has beat us to it, since we don't want anything weird to
416 * happen when we wake up.
417 * Then, do the setup for suspend, enter the state, and cleaup (after
420 static int enter_state(suspend_state_t state
)
424 if (!valid_state(state
))
427 if (!mutex_trylock(&pm_mutex
))
430 printk(KERN_INFO
"PM: Syncing filesystems ... ");
434 pr_debug("PM: Preparing system for %s sleep\n", pm_states
[state
]);
435 error
= suspend_prepare();
439 if (suspend_test(TEST_FREEZER
))
442 pr_debug("PM: Entering %s sleep\n", pm_states
[state
]);
443 error
= suspend_devices_and_enter(state
);
446 pr_debug("PM: Finishing wakeup.\n");
449 mutex_unlock(&pm_mutex
);
455 * pm_suspend - Externally visible function for suspending system.
456 * @state: Enumerated value of state to enter.
458 * Determine whether or not value is within range, get state
459 * structure, and enter (above).
462 int pm_suspend(suspend_state_t state
)
464 if (state
> PM_SUSPEND_ON
&& state
<= PM_SUSPEND_MAX
)
465 return enter_state(state
);
469 EXPORT_SYMBOL(pm_suspend
);
471 #endif /* CONFIG_SUSPEND */
473 struct kobject
*power_kobj
;
476 * state - control system power state.
478 * show() returns what states are supported, which is hard-coded to
479 * 'standby' (Power-On Suspend), 'mem' (Suspend-to-RAM), and
480 * 'disk' (Suspend-to-Disk).
482 * store() accepts one of those strings, translates it into the
483 * proper enumerated value, and initiates a suspend transition.
486 static ssize_t
state_show(struct kobject
*kobj
, struct kobj_attribute
*attr
,
490 #ifdef CONFIG_SUSPEND
493 for (i
= 0; i
< PM_SUSPEND_MAX
; i
++) {
494 if (pm_states
[i
] && valid_state(i
))
495 s
+= sprintf(s
,"%s ", pm_states
[i
]);
498 #ifdef CONFIG_HIBERNATION
499 s
+= sprintf(s
, "%s\n", "disk");
502 /* convert the last space to a newline */
508 static ssize_t
state_store(struct kobject
*kobj
, struct kobj_attribute
*attr
,
509 const char *buf
, size_t n
)
511 #ifdef CONFIG_SUSPEND
512 suspend_state_t state
= PM_SUSPEND_STANDBY
;
513 const char * const *s
;
519 p
= memchr(buf
, '\n', n
);
520 len
= p
? p
- buf
: n
;
522 /* First, check if we are requested to hibernate */
523 if (len
== 4 && !strncmp(buf
, "disk", len
)) {
528 #ifdef CONFIG_SUSPEND
529 for (s
= &pm_states
[state
]; state
< PM_SUSPEND_MAX
; s
++, state
++) {
530 if (*s
&& len
== strlen(*s
) && !strncmp(buf
, *s
, len
))
533 if (state
< PM_SUSPEND_MAX
&& *s
)
534 error
= enter_state(state
);
538 return error
? error
: n
;
543 #ifdef CONFIG_PM_TRACE
544 int pm_trace_enabled
;
546 static ssize_t
pm_trace_show(struct kobject
*kobj
, struct kobj_attribute
*attr
,
549 return sprintf(buf
, "%d\n", pm_trace_enabled
);
553 pm_trace_store(struct kobject
*kobj
, struct kobj_attribute
*attr
,
554 const char *buf
, size_t n
)
558 if (sscanf(buf
, "%d", &val
) == 1) {
559 pm_trace_enabled
= !!val
;
565 power_attr(pm_trace
);
566 #endif /* CONFIG_PM_TRACE */
568 static struct attribute
* g
[] = {
570 #ifdef CONFIG_PM_TRACE
573 #if defined(CONFIG_PM_SLEEP) && defined(CONFIG_PM_DEBUG)
579 static struct attribute_group attr_group
= {
584 static int __init
pm_init(void)
586 power_kobj
= kobject_create_and_add("power", NULL
);
589 return sysfs_create_group(power_kobj
, &attr_group
);
592 core_initcall(pm_init
);
595 #ifdef CONFIG_PM_TEST_SUSPEND
597 #include <linux/rtc.h>
600 * To test system suspend, we need a hands-off mechanism to resume the
601 * system. RTCs wake alarms are a common self-contained mechanism.
604 static void __init
test_wakealarm(struct rtc_device
*rtc
, suspend_state_t state
)
606 static char err_readtime
[] __initdata
=
607 KERN_ERR
"PM: can't read %s time, err %d\n";
608 static char err_wakealarm
[] __initdata
=
609 KERN_ERR
"PM: can't set %s wakealarm, err %d\n";
610 static char err_suspend
[] __initdata
=
611 KERN_ERR
"PM: suspend test failed, error %d\n";
612 static char info_test
[] __initdata
=
613 KERN_INFO
"PM: test RTC wakeup from '%s' suspend\n";
616 struct rtc_wkalrm alm
;
619 /* this may fail if the RTC hasn't been initialized */
620 status
= rtc_read_time(rtc
, &alm
.time
);
622 printk(err_readtime
, dev_name(&rtc
->dev
), status
);
625 rtc_tm_to_time(&alm
.time
, &now
);
627 memset(&alm
, 0, sizeof alm
);
628 rtc_time_to_tm(now
+ TEST_SUSPEND_SECONDS
, &alm
.time
);
631 status
= rtc_set_alarm(rtc
, &alm
);
633 printk(err_wakealarm
, dev_name(&rtc
->dev
), status
);
637 if (state
== PM_SUSPEND_MEM
) {
638 printk(info_test
, pm_states
[state
]);
639 status
= pm_suspend(state
);
640 if (status
== -ENODEV
)
641 state
= PM_SUSPEND_STANDBY
;
643 if (state
== PM_SUSPEND_STANDBY
) {
644 printk(info_test
, pm_states
[state
]);
645 status
= pm_suspend(state
);
648 printk(err_suspend
, status
);
650 /* Some platforms can't detect that the alarm triggered the
651 * wakeup, or (accordingly) disable it after it afterwards.
652 * It's supposed to give oneshot behavior; cope.
655 rtc_set_alarm(rtc
, &alm
);
658 static int __init
has_wakealarm(struct device
*dev
, void *name_ptr
)
660 struct rtc_device
*candidate
= to_rtc_device(dev
);
662 if (!candidate
->ops
->set_alarm
)
664 if (!device_may_wakeup(candidate
->dev
.parent
))
667 *(const char **)name_ptr
= dev_name(dev
);
672 * Kernel options like "test_suspend=mem" force suspend/resume sanity tests
673 * at startup time. They're normally disabled, for faster boot and because
674 * we can't know which states really work on this particular system.
676 static suspend_state_t test_state __initdata
= PM_SUSPEND_ON
;
678 static char warn_bad_state
[] __initdata
=
679 KERN_WARNING
"PM: can't test '%s' suspend state\n";
681 static int __init
setup_test_suspend(char *value
)
685 /* "=mem" ==> "mem" */
687 for (i
= 0; i
< PM_SUSPEND_MAX
; i
++) {
690 if (strcmp(pm_states
[i
], value
) != 0)
692 test_state
= (__force suspend_state_t
) i
;
695 printk(warn_bad_state
, value
);
698 __setup("test_suspend", setup_test_suspend
);
700 static int __init
test_suspend(void)
702 static char warn_no_rtc
[] __initdata
=
703 KERN_WARNING
"PM: no wakealarm-capable RTC driver is ready\n";
706 struct rtc_device
*rtc
= NULL
;
708 /* PM is initialized by now; is that state testable? */
709 if (test_state
== PM_SUSPEND_ON
)
711 if (!valid_state(test_state
)) {
712 printk(warn_bad_state
, pm_states
[test_state
]);
716 /* RTCs have initialized by now too ... can we use one? */
717 class_find_device(rtc_class
, NULL
, &pony
, has_wakealarm
);
719 rtc
= rtc_class_open(pony
);
726 test_wakealarm(rtc
, test_state
);
727 rtc_class_close(rtc
);
731 late_initcall(test_suspend
);
733 #endif /* CONFIG_PM_TEST_SUSPEND */