[deliverable/linux.git] / kernel / power / main.c

/*
 * kernel/power/main.c - PM subsystem core functionality.
 *
 * Copyright (c) 2003 Patrick Mochel
 * Copyright (c) 2003 Open Source Development Lab
 * 
 * This file is released under the GPLv2
 *
 */

#include <linux/kobject.h>
#include <linux/string.h>
#include <linux/resume-trace.h>
#include <linux/workqueue.h>

#include "power.h"

DEFINE_MUTEX(pm_mutex);

#ifdef CONFIG_PM_SLEEP

/* Routines for PM-transition notifications */

static BLOCKING_NOTIFIER_HEAD(pm_chain_head);

int register_pm_notifier(struct notifier_block *nb)
{
	return blocking_notifier_chain_register(&pm_chain_head, nb);
}
EXPORT_SYMBOL_GPL(register_pm_notifier);

int unregister_pm_notifier(struct notifier_block *nb)
{
	return blocking_notifier_chain_unregister(&pm_chain_head, nb);
}
EXPORT_SYMBOL_GPL(unregister_pm_notifier);

int pm_notifier_call_chain(unsigned long val)
{
	int ret = blocking_notifier_call_chain(&pm_chain_head, val, NULL);

	return notifier_to_errno(ret);
}

/* If set, devices may be suspended and resumed asynchronously. */
int pm_async_enabled = 1;

static ssize_t pm_async_show(struct kobject *kobj, struct kobj_attribute *attr,
			     char *buf)
{
	return sprintf(buf, "%d\n", pm_async_enabled);
}

static ssize_t pm_async_store(struct kobject *kobj, struct kobj_attribute *attr,
			      const char *buf, size_t n)
{
	unsigned long val;

	if (strict_strtoul(buf, 10, &val))
		return -EINVAL;

	if (val > 1)
		return -EINVAL;

	pm_async_enabled = val;
	return n;
}

power_attr(pm_async);

#ifdef CONFIG_PM_DEBUG
int pm_test_level = TEST_NONE;

static const char * const pm_tests[__TEST_AFTER_LAST] = {
	[TEST_NONE] = "none",
	[TEST_CORE] = "core",
	[TEST_CPUS] = "processors",
	[TEST_PLATFORM] = "platform",
	[TEST_DEVICES] = "devices",
	[TEST_FREEZER] = "freezer",
};

static ssize_t pm_test_show(struct kobject *kobj, struct kobj_attribute *attr,
				char *buf)
{
	char *s = buf;
	int level;

	for (level = TEST_FIRST; level <= TEST_MAX; level++)
		if (pm_tests[level]) {
			if (level == pm_test_level)
				s += sprintf(s, "[%s] ", pm_tests[level]);
			else
				s += sprintf(s, "%s ", pm_tests[level]);
		}

	if (s != buf)
		/* convert the last space to a newline */
		*(s-1) = '\n';

	return (s - buf);
}

static ssize_t pm_test_store(struct kobject *kobj, struct kobj_attribute *attr,
				const char *buf, size_t n)
{
	const char * const *s;
	int level;
	char *p;
	int len;
	int error = -EINVAL;

	p = memchr(buf, '\n', n);
	len = p ? p - buf : n;

	mutex_lock(&pm_mutex);

	level = TEST_FIRST;
	for (s = &pm_tests[level]; level <= TEST_MAX; s++, level++)
		if (*s && len == strlen(*s) && !strncmp(buf, *s, len)) {
			pm_test_level = level;
			error = 0;
			break;
		}

	mutex_unlock(&pm_mutex);

	return error ? error : n;
}

power_attr(pm_test);
#endif /* CONFIG_PM_DEBUG */

#endif /* CONFIG_PM_SLEEP */

struct kobject *power_kobj;

/**
 *	state - control system power state.
 *
 *	show() returns what states are supported, which is hard-coded to
 *	'standby' (Power-On Suspend), 'mem' (Suspend-to-RAM), and
 *	'disk' (Suspend-to-Disk).
 *
 *	store() accepts one of those strings, translates it into the 
 *	proper enumerated value, and initiates a suspend transition.
 */
static ssize_t state_show(struct kobject *kobj, struct kobj_attribute *attr,
			  char *buf)
{
	char *s = buf;
#ifdef CONFIG_SUSPEND
	int i;

	for (i = 0; i < PM_SUSPEND_MAX; i++) {
		if (pm_states[i] && valid_state(i))
			s += sprintf(s,"%s ", pm_states[i]);
	}
#endif
#ifdef CONFIG_HIBERNATION
	s += sprintf(s, "%s\n", "disk");
#else
	if (s != buf)
		/* convert the last space to a newline */
		*(s-1) = '\n';
#endif
	return (s - buf);
}

static ssize_t state_store(struct kobject *kobj, struct kobj_attribute *attr,
			   const char *buf, size_t n)
{
#ifdef CONFIG_SUSPEND
	suspend_state_t state = PM_SUSPEND_STANDBY;
	const char * const *s;
#endif
	char *p;
	int len;
	int error = -EINVAL;

	p = memchr(buf, '\n', n);
	len = p ? p - buf : n;

	/* First, check if we are requested to hibernate */
	if (len == 4 && !strncmp(buf, "disk", len)) {
		error = hibernate();
  goto Exit;
	}

#ifdef CONFIG_SUSPEND
	for (s = &pm_states[state]; state < PM_SUSPEND_MAX; s++, state++) {
		if (*s && len == strlen(*s) && !strncmp(buf, *s, len))
			break;
	}
	if (state < PM_SUSPEND_MAX && *s)
		error = enter_state(state);
#endif

 Exit:
	return error ? error : n;
}

power_attr(state);

#ifdef CONFIG_PM_SLEEP
/*
 * The 'wakeup_count' attribute, along with the functions defined in
 * drivers/base/power/wakeup.c, provides a means by which wakeup events can be
 * handled in a non-racy way.
 *
 * If a wakeup event occurs when the system is in a sleep state, it simply is
 * woken up.  In turn, if an event that would wake the system up from a sleep
 * state occurs when it is undergoing a transition to that sleep state, the
 * transition should be aborted.  Moreover, if such an event occurs when the
 * system is in the working state, an attempt to start a transition to the
 * given sleep state should fail during certain period after the detection of
 * the event.  Using the 'state' attribute alone is not sufficient to satisfy
 * these requirements, because a wakeup event may occur exactly when 'state'
 * is being written to and may be delivered to user space right before it is
 * frozen, so the event will remain only partially processed until the system is
 * woken up by another event.  In particular, it won't cause the transition to
 * a sleep state to be aborted.
 *
 * This difficulty may be overcome if user space uses 'wakeup_count' before
 * writing to 'state'.  It first should read from 'wakeup_count' and store
 * the read value.  Then, after carrying out its own preparations for the system
 * transition to a sleep state, it should write the stored value to
 * 'wakeup_count'.  If that fails, at least one wakeup event has occurred since
 * 'wakeup_count' was read and 'state' should not be written to.  Otherwise, it
 * is allowed to write to 'state', but the transition will be aborted if there
 * are any wakeup events detected after 'wakeup_count' was written to.
 */

static ssize_t wakeup_count_show(struct kobject *kobj,
				struct kobj_attribute *attr,
				char *buf)
{
	unsigned int val;

	return pm_get_wakeup_count(&val) ? sprintf(buf, "%u\n", val) : -EINTR;
}

static ssize_t wakeup_count_store(struct kobject *kobj,
				struct kobj_attribute *attr,
				const char *buf, size_t n)
{
	unsigned int val;

	if (sscanf(buf, "%u", &val) == 1) {
		if (pm_save_wakeup_count(val))
			return n;
	}
	return -EINVAL;
}

power_attr(wakeup_count);
#endif /* CONFIG_PM_SLEEP */

#ifdef CONFIG_PM_TRACE
int pm_trace_enabled;

static ssize_t pm_trace_show(struct kobject *kobj, struct kobj_attribute *attr,
			     char *buf)
{
	return sprintf(buf, "%d\n", pm_trace_enabled);
}

static ssize_t
pm_trace_store(struct kobject *kobj, struct kobj_attribute *attr,
	       const char *buf, size_t n)
{
	int val;

	if (sscanf(buf, "%d", &val) == 1) {
		pm_trace_enabled = !!val;
		return n;
	}
	return -EINVAL;
}

power_attr(pm_trace);

static ssize_t pm_trace_dev_match_show(struct kobject *kobj,
				       struct kobj_attribute *attr,
				       char *buf)
{
	return show_trace_dev_match(buf, PAGE_SIZE);
}

static ssize_t
pm_trace_dev_match_store(struct kobject *kobj, struct kobj_attribute *attr,
			 const char *buf, size_t n)
{
	return -EINVAL;
}

power_attr(pm_trace_dev_match);

#endif /* CONFIG_PM_TRACE */

static struct attribute * g[] = {
	&state_attr.attr,
#ifdef CONFIG_PM_TRACE
	&pm_trace_attr.attr,
	&pm_trace_dev_match_attr.attr,
#endif
#ifdef CONFIG_PM_SLEEP
	&pm_async_attr.attr,
	&wakeup_count_attr.attr,
#ifdef CONFIG_PM_DEBUG
	&pm_test_attr.attr,
#endif
#endif
	NULL,
};

static struct attribute_group attr_group = {
	.attrs = g,
};

#ifdef CONFIG_PM_RUNTIME
struct workqueue_struct *pm_wq;
EXPORT_SYMBOL_GPL(pm_wq);

static int __init pm_start_workqueue(void)
{
	pm_wq = alloc_workqueue("pm", WQ_FREEZABLE, 0);

	return pm_wq ? 0 : -ENOMEM;
}
#else
static inline int pm_start_workqueue(void) { return 0; }
#endif

static int __init pm_init(void)
{
	int error = pm_start_workqueue();
	if (error)
		return error;
	hibernate_image_size_init();
	hibernate_reserved_size_init();
	power_kobj = kobject_create_and_add("power", NULL);
	if (!power_kobj)
		return -ENOMEM;
	return sysfs_create_group(power_kobj, &attr_group);
}

core_initcall(pm_init);
Commit	Line	Data
1da177e4 LT	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
1da177e4 LT	11	#include <linux/kobject.h>
1da177e4 LT	12	#include <linux/string.h>
c5c6ba4e	13	#include <linux/resume-trace.h>
5e928f77	14	#include <linux/workqueue.h>
1da177e4 LT	15
	16	#include "power.h"
	17
a6d70980	18	DEFINE_MUTEX(pm_mutex);
1da177e4	19
cd51e61c RW	20	#ifdef CONFIG_PM_SLEEP
cd51e61c RW	21
82525756 AS	22	/* Routines for PM-transition notifications */
	23
	24	static BLOCKING_NOTIFIER_HEAD(pm_chain_head);
	25
	26	int register_pm_notifier(struct notifier_block *nb)
	27	{
	28	return blocking_notifier_chain_register(&pm_chain_head, nb);
	29	}
	30	EXPORT_SYMBOL_GPL(register_pm_notifier);
	31
	32	int unregister_pm_notifier(struct notifier_block *nb)
	33	{
	34	return blocking_notifier_chain_unregister(&pm_chain_head, nb);
	35	}
	36	EXPORT_SYMBOL_GPL(unregister_pm_notifier);
	37
	38	int pm_notifier_call_chain(unsigned long val)
	39	{
f0c077a8 AM	40	int ret = blocking_notifier_call_chain(&pm_chain_head, val, NULL);
	41
	42	return notifier_to_errno(ret);
82525756 AS	43	}
82525756 AS	44
0e06b4a8 RW	45	/* If set, devices may be suspended and resumed asynchronously. */
	46	int pm_async_enabled = 1;
	47
	48	static ssize_t pm_async_show(struct kobject kobj, struct kobj_attribute attr,
	49	char *buf)
	50	{
	51	return sprintf(buf, "%d\n", pm_async_enabled);
	52	}
	53
	54	static ssize_t pm_async_store(struct kobject kobj, struct kobj_attribute attr,
	55	const char *buf, size_t n)
	56	{
	57	unsigned long val;
	58
	59	if (strict_strtoul(buf, 10, &val))
	60	return -EINVAL;
	61
	62	if (val > 1)
	63	return -EINVAL;
	64
	65	pm_async_enabled = val;
	66	return n;
	67	}
	68
	69	power_attr(pm_async);
	70
0e7d56e3 RW	71	#ifdef CONFIG_PM_DEBUG
	72	int pm_test_level = TEST_NONE;
	73
0e7d56e3 RW	74	static const char * const pm_tests[__TEST_AFTER_LAST] = {
	75	[TEST_NONE] = "none",
	76	[TEST_CORE] = "core",
	77	[TEST_CPUS] = "processors",
	78	[TEST_PLATFORM] = "platform",
	79	[TEST_DEVICES] = "devices",
	80	[TEST_FREEZER] = "freezer",
	81	};
	82
039a75c6 RW	83	static ssize_t pm_test_show(struct kobject kobj, struct kobj_attribute attr,
039a75c6 RW	84	char *buf)
0e7d56e3 RW	85	{
	86	char *s = buf;
	87	int level;
	88
	89	for (level = TEST_FIRST; level <= TEST_MAX; level++)
	90	if (pm_tests[level]) {
	91	if (level == pm_test_level)
	92	s += sprintf(s, "[%s] ", pm_tests[level]);
	93	else
	94	s += sprintf(s, "%s ", pm_tests[level]);
	95	}
	96
	97	if (s != buf)
	98	/* convert the last space to a newline */
	99	*(s-1) = '\n';
	100
	101	return (s - buf);
	102	}
	103
039a75c6 RW	104	static ssize_t pm_test_store(struct kobject kobj, struct kobj_attribute attr,
039a75c6 RW	105	const char *buf, size_t n)
0e7d56e3 RW	106	{
	107	const char * const *s;
	108	int level;
	109	char *p;
	110	int len;
	111	int error = -EINVAL;
	112
	113	p = memchr(buf, '\n', n);
	114	len = p ? p - buf : n;
	115
	116	mutex_lock(&pm_mutex);
	117
	118	level = TEST_FIRST;
	119	for (s = &pm_tests[level]; level <= TEST_MAX; s++, level++)
	120	if (s && len == strlen(s) && !strncmp(buf, *s, len)) {
	121	pm_test_level = level;
	122	error = 0;
	123	break;
	124	}
	125
	126	mutex_unlock(&pm_mutex);
	127
	128	return error ? error : n;
	129	}
	130
	131	power_attr(pm_test);
091d71e0	132	#endif /* CONFIG_PM_DEBUG */
0e7d56e3	133
7671b8ae	134	#endif /* CONFIG_PM_SLEEP */
039a75c6	135
d76e15fb	136	struct kobject *power_kobj;
1da177e4 LT	137
	138	/**
	139	* state - control system power state.
	140	*
	141	* show() returns what states are supported, which is hard-coded to
	142	* 'standby' (Power-On Suspend), 'mem' (Suspend-to-RAM), and
	143	* 'disk' (Suspend-to-Disk).
	144	*
	145	* store() accepts one of those strings, translates it into the
	146	* proper enumerated value, and initiates a suspend transition.
	147	*/
386f275f KS	148	static ssize_t state_show(struct kobject kobj, struct kobj_attribute attr,
386f275f KS	149	char *buf)
1da177e4	150	{
296699de RW	151	char *s = buf;
296699de RW	152	#ifdef CONFIG_SUSPEND
1da177e4	153	int i;
1da177e4 LT	154
1da177e4 LT	155	for (i = 0; i < PM_SUSPEND_MAX; i++) {
123d3c13 PM	156	if (pm_states[i] && valid_state(i))
123d3c13 PM	157	s += sprintf(s,"%s ", pm_states[i]);
1da177e4	158	}
296699de	159	#endif
b0cb1a19	160	#ifdef CONFIG_HIBERNATION
a3d25c27 RW	161	s += sprintf(s, "%s\n", "disk");
	162	#else
	163	if (s != buf)
	164	/* convert the last space to a newline */
	165	*(s-1) = '\n';
	166	#endif
1da177e4 LT	167	return (s - buf);
	168	}
	169
386f275f KS	170	static ssize_t state_store(struct kobject kobj, struct kobj_attribute attr,
386f275f KS	171	const char *buf, size_t n)
1da177e4	172	{
296699de	173	#ifdef CONFIG_SUSPEND
1da177e4	174	suspend_state_t state = PM_SUSPEND_STANDBY;
3b364b8d	175	const char * const *s;
296699de	176	#endif
1da177e4	177	char *p;
1da177e4	178	int len;
296699de	179	int error = -EINVAL;
1da177e4 LT	180
	181	p = memchr(buf, '\n', n);
	182	len = p ? p - buf : n;
	183
a3d25c27	184	/* First, check if we are requested to hibernate */
8d98a690	185	if (len == 4 && !strncmp(buf, "disk", len)) {
a3d25c27	186	error = hibernate();
296699de	187	goto Exit;
a3d25c27 RW	188	}
a3d25c27 RW	189
296699de	190	#ifdef CONFIG_SUSPEND
1da177e4	191	for (s = &pm_states[state]; state < PM_SUSPEND_MAX; s++, state++) {
8d98a690	192	if (s && len == strlen(s) && !strncmp(buf, *s, len))
1da177e4 LT	193	break;
1da177e4 LT	194	}
47bb7899	195	if (state < PM_SUSPEND_MAX && *s)
1da177e4	196	error = enter_state(state);
296699de RW	197	#endif
	198
	199	Exit:
1da177e4 LT	200	return error ? error : n;
	201	}
	202
	203	power_attr(state);
	204
c125e96f RW	205	#ifdef CONFIG_PM_SLEEP
	206	/*
	207	* The 'wakeup_count' attribute, along with the functions defined in
	208	* drivers/base/power/wakeup.c, provides a means by which wakeup events can be
	209	* handled in a non-racy way.
	210	*
	211	* If a wakeup event occurs when the system is in a sleep state, it simply is
	212	* woken up. In turn, if an event that would wake the system up from a sleep
	213	* state occurs when it is undergoing a transition to that sleep state, the
	214	* transition should be aborted. Moreover, if such an event occurs when the
	215	* system is in the working state, an attempt to start a transition to the
	216	* given sleep state should fail during certain period after the detection of
	217	* the event. Using the 'state' attribute alone is not sufficient to satisfy
	218	* these requirements, because a wakeup event may occur exactly when 'state'
	219	* is being written to and may be delivered to user space right before it is
	220	* frozen, so the event will remain only partially processed until the system is
	221	* woken up by another event. In particular, it won't cause the transition to
	222	* a sleep state to be aborted.
	223	*
	224	* This difficulty may be overcome if user space uses 'wakeup_count' before
	225	* writing to 'state'. It first should read from 'wakeup_count' and store
	226	* the read value. Then, after carrying out its own preparations for the system
	227	* transition to a sleep state, it should write the stored value to
25985edc	228	* 'wakeup_count'. If that fails, at least one wakeup event has occurred since
c125e96f RW	229	* 'wakeup_count' was read and 'state' should not be written to. Otherwise, it
	230	* is allowed to write to 'state', but the transition will be aborted if there
	231	* are any wakeup events detected after 'wakeup_count' was written to.
	232	*/
	233
	234	static ssize_t wakeup_count_show(struct kobject *kobj,
	235	struct kobj_attribute *attr,
	236	char *buf)
	237	{
074037ec	238	unsigned int val;
c125e96f	239
074037ec	240	return pm_get_wakeup_count(&val) ? sprintf(buf, "%u\n", val) : -EINTR;
c125e96f RW	241	}
	242
	243	static ssize_t wakeup_count_store(struct kobject *kobj,
	244	struct kobj_attribute *attr,
	245	const char *buf, size_t n)
	246	{
074037ec	247	unsigned int val;
c125e96f	248
074037ec	249	if (sscanf(buf, "%u", &val) == 1) {
c125e96f RW	250	if (pm_save_wakeup_count(val))
	251	return n;
	252	}
	253	return -EINVAL;
	254	}
	255
	256	power_attr(wakeup_count);
	257	#endif /* CONFIG_PM_SLEEP */
	258
c5c6ba4e RW	259	#ifdef CONFIG_PM_TRACE
	260	int pm_trace_enabled;
	261
386f275f KS	262	static ssize_t pm_trace_show(struct kobject kobj, struct kobj_attribute attr,
386f275f KS	263	char *buf)
c5c6ba4e RW	264	{
	265	return sprintf(buf, "%d\n", pm_trace_enabled);
	266	}
	267
	268	static ssize_t
386f275f KS	269	pm_trace_store(struct kobject kobj, struct kobj_attribute attr,
386f275f KS	270	const char *buf, size_t n)
c5c6ba4e RW	271	{
	272	int val;
	273
	274	if (sscanf(buf, "%d", &val) == 1) {
	275	pm_trace_enabled = !!val;
	276	return n;
	277	}
	278	return -EINVAL;
	279	}
	280
	281	power_attr(pm_trace);
d33ac60b JH	282
	283	static ssize_t pm_trace_dev_match_show(struct kobject *kobj,
	284	struct kobj_attribute *attr,
	285	char *buf)
	286	{
	287	return show_trace_dev_match(buf, PAGE_SIZE);
	288	}
	289
	290	static ssize_t
	291	pm_trace_dev_match_store(struct kobject kobj, struct kobj_attribute attr,
	292	const char *buf, size_t n)
	293	{
	294	return -EINVAL;
	295	}
	296
	297	power_attr(pm_trace_dev_match);
	298
0e7d56e3	299	#endif /* CONFIG_PM_TRACE */
c5c6ba4e RW	300
	301	static struct attribute * g[] = {
	302	&state_attr.attr,
0e7d56e3	303	#ifdef CONFIG_PM_TRACE
c5c6ba4e	304	&pm_trace_attr.attr,
d33ac60b	305	&pm_trace_dev_match_attr.attr,
0e7d56e3	306	#endif
0e06b4a8 RW	307	#ifdef CONFIG_PM_SLEEP
0e06b4a8 RW	308	&pm_async_attr.attr,
c125e96f	309	&wakeup_count_attr.attr,
0e06b4a8	310	#ifdef CONFIG_PM_DEBUG
0e7d56e3	311	&pm_test_attr.attr,
0e06b4a8	312	#endif
0e7d56e3	313	#endif
c5c6ba4e RW	314	NULL,
c5c6ba4e RW	315	};
1da177e4 LT	316
	317	static struct attribute_group attr_group = {
	318	.attrs = g,
	319	};
	320
5e928f77 RW	321	#ifdef CONFIG_PM_RUNTIME
5e928f77 RW	322	struct workqueue_struct *pm_wq;
7b199ca2	323	EXPORT_SYMBOL_GPL(pm_wq);
5e928f77 RW	324
	325	static int __init pm_start_workqueue(void)
	326	{
58a69cb4	327	pm_wq = alloc_workqueue("pm", WQ_FREEZABLE, 0);
5e928f77 RW	328
	329	return pm_wq ? 0 : -ENOMEM;
	330	}
	331	#else
	332	static inline int pm_start_workqueue(void) { return 0; }
	333	#endif
	334
1da177e4 LT	335	static int __init pm_init(void)
1da177e4 LT	336	{
5e928f77 RW	337	int error = pm_start_workqueue();
	338	if (error)
	339	return error;
ac5c24ec	340	hibernate_image_size_init();
ddeb6487	341	hibernate_reserved_size_init();
d76e15fb GKH	342	power_kobj = kobject_create_and_add("power", NULL);
d76e15fb GKH	343	if (!power_kobj)
039a5dcd	344	return -ENOMEM;
d76e15fb	345	return sysfs_create_group(power_kobj, &attr_group);
1da177e4 LT	346	}
	347
	348	core_initcall(pm_init);