[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/export.h>
#include <linux/kobject.h>
#include <linux/string.h>
#include <linux/resume-trace.h>
#include <linux/workqueue.h>
#include <linux/debugfs.h>
#include <linux/seq_file.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 */

#ifdef CONFIG_DEBUG_FS
static char *suspend_step_name(enum suspend_stat_step step)
{
	switch (step) {
	case SUSPEND_FREEZE:
		return "freeze";
	case SUSPEND_PREPARE:
		return "prepare";
	case SUSPEND_SUSPEND:
		return "suspend";
	case SUSPEND_SUSPEND_NOIRQ:
		return "suspend_noirq";
	case SUSPEND_RESUME_NOIRQ:
		return "resume_noirq";
	case SUSPEND_RESUME:
		return "resume";
	default:
		return "";
	}
}

static int suspend_stats_show(struct seq_file *s, void *unused)
{
	int i, index, last_dev, last_errno, last_step;

	last_dev = suspend_stats.last_failed_dev + REC_FAILED_NUM - 1;
	last_dev %= REC_FAILED_NUM;
	last_errno = suspend_stats.last_failed_errno + REC_FAILED_NUM - 1;
	last_errno %= REC_FAILED_NUM;
	last_step = suspend_stats.last_failed_step + REC_FAILED_NUM - 1;
	last_step %= REC_FAILED_NUM;
	seq_printf(s, "%s: %d\n%s: %d\n%s: %d\n%s: %d\n"
			"%s: %d\n%s: %d\n%s: %d\n%s: %d\n",
			"success", suspend_stats.success,
			"fail", suspend_stats.fail,
			"failed_freeze", suspend_stats.failed_freeze,
			"failed_prepare", suspend_stats.failed_prepare,
			"failed_suspend", suspend_stats.failed_suspend,
			"failed_suspend_noirq",
				suspend_stats.failed_suspend_noirq,
			"failed_resume", suspend_stats.failed_resume,
			"failed_resume_noirq",
				suspend_stats.failed_resume_noirq);
	seq_printf(s,	"failures:\n  last_failed_dev:\t%-s\n",
			suspend_stats.failed_devs[last_dev]);
	for (i = 1; i < REC_FAILED_NUM; i++) {
		index = last_dev + REC_FAILED_NUM - i;
		index %= REC_FAILED_NUM;
		seq_printf(s, "\t\t\t%-s\n",
			suspend_stats.failed_devs[index]);
	}
	seq_printf(s,	"  last_failed_errno:\t%-d\n",
			suspend_stats.errno[last_errno]);
	for (i = 1; i < REC_FAILED_NUM; i++) {
		index = last_errno + REC_FAILED_NUM - i;
		index %= REC_FAILED_NUM;
		seq_printf(s, "\t\t\t%-d\n",
			suspend_stats.errno[index]);
	}
	seq_printf(s,	"  last_failed_step:\t%-s\n",
			suspend_step_name(
				suspend_stats.failed_steps[last_step]));
	for (i = 1; i < REC_FAILED_NUM; i++) {
		index = last_step + REC_FAILED_NUM - i;
		index %= REC_FAILED_NUM;
		seq_printf(s, "\t\t\t%-s\n",
			suspend_step_name(
				suspend_stats.failed_steps[index]));
	}

	return 0;
}

static int suspend_stats_open(struct inode *inode, struct file *file)
{
	return single_open(file, suspend_stats_show, NULL);
}

static const struct file_operations suspend_stats_operations = {
	.open           = suspend_stats_open,
	.read           = seq_read,
	.llseek         = seq_lseek,
	.release        = single_release,
};

static int __init pm_debugfs_init(void)
{
	debugfs_create_file("suspend_stats", S_IFREG | S_IRUGO,
			NULL, NULL, &suspend_stats_operations);
	return 0;
}

late_initcall(pm_debugfs_init);
#endif /* CONFIG_DEBUG_FS */

#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);
		if (error) {
			suspend_stats.fail++;
			dpm_save_failed_errno(error);
		} else
			suspend_stats.success++;
	}
#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
341d4166	6	*
1da177e4 LT	7	* This file is released under the GPLv2
	8	*
	9	*/
	10
6e5fdeed	11	#include <linux/export.h>
1da177e4 LT	12	#include <linux/kobject.h>
1da177e4 LT	13	#include <linux/string.h>
c5c6ba4e	14	#include <linux/resume-trace.h>
5e928f77	15	#include <linux/workqueue.h>
2a77c46d SL	16	#include <linux/debugfs.h>
2a77c46d SL	17	#include <linux/seq_file.h>
1da177e4 LT	18
	19	#include "power.h"
	20
a6d70980	21	DEFINE_MUTEX(pm_mutex);
1da177e4	22
cd51e61c RW	23	#ifdef CONFIG_PM_SLEEP
cd51e61c RW	24
82525756 AS	25	/* Routines for PM-transition notifications */
	26
	27	static BLOCKING_NOTIFIER_HEAD(pm_chain_head);
	28
	29	int register_pm_notifier(struct notifier_block *nb)
	30	{
	31	return blocking_notifier_chain_register(&pm_chain_head, nb);
	32	}
	33	EXPORT_SYMBOL_GPL(register_pm_notifier);
	34
	35	int unregister_pm_notifier(struct notifier_block *nb)
	36	{
	37	return blocking_notifier_chain_unregister(&pm_chain_head, nb);
	38	}
	39	EXPORT_SYMBOL_GPL(unregister_pm_notifier);
	40
	41	int pm_notifier_call_chain(unsigned long val)
	42	{
f0c077a8 AM	43	int ret = blocking_notifier_call_chain(&pm_chain_head, val, NULL);
	44
	45	return notifier_to_errno(ret);
82525756 AS	46	}
82525756 AS	47
0e06b4a8 RW	48	/* If set, devices may be suspended and resumed asynchronously. */
	49	int pm_async_enabled = 1;
	50
	51	static ssize_t pm_async_show(struct kobject kobj, struct kobj_attribute attr,
	52	char *buf)
	53	{
	54	return sprintf(buf, "%d\n", pm_async_enabled);
	55	}
	56
	57	static ssize_t pm_async_store(struct kobject kobj, struct kobj_attribute attr,
	58	const char *buf, size_t n)
	59	{
	60	unsigned long val;
	61
	62	if (strict_strtoul(buf, 10, &val))
	63	return -EINVAL;
	64
	65	if (val > 1)
	66	return -EINVAL;
	67
	68	pm_async_enabled = val;
	69	return n;
	70	}
	71
	72	power_attr(pm_async);
	73
0e7d56e3 RW	74	#ifdef CONFIG_PM_DEBUG
	75	int pm_test_level = TEST_NONE;
	76
0e7d56e3 RW	77	static const char * const pm_tests[__TEST_AFTER_LAST] = {
	78	[TEST_NONE] = "none",
	79	[TEST_CORE] = "core",
	80	[TEST_CPUS] = "processors",
	81	[TEST_PLATFORM] = "platform",
	82	[TEST_DEVICES] = "devices",
	83	[TEST_FREEZER] = "freezer",
	84	};
	85
039a75c6 RW	86	static ssize_t pm_test_show(struct kobject kobj, struct kobj_attribute attr,
039a75c6 RW	87	char *buf)
0e7d56e3 RW	88	{
	89	char *s = buf;
	90	int level;
	91
	92	for (level = TEST_FIRST; level <= TEST_MAX; level++)
	93	if (pm_tests[level]) {
	94	if (level == pm_test_level)
	95	s += sprintf(s, "[%s] ", pm_tests[level]);
	96	else
	97	s += sprintf(s, "%s ", pm_tests[level]);
	98	}
	99
	100	if (s != buf)
	101	/* convert the last space to a newline */
	102	*(s-1) = '\n';
	103
	104	return (s - buf);
	105	}
	106
039a75c6 RW	107	static ssize_t pm_test_store(struct kobject kobj, struct kobj_attribute attr,
039a75c6 RW	108	const char *buf, size_t n)
0e7d56e3 RW	109	{
	110	const char * const *s;
	111	int level;
	112	char *p;
	113	int len;
	114	int error = -EINVAL;
	115
	116	p = memchr(buf, '\n', n);
	117	len = p ? p - buf : n;
	118
	119	mutex_lock(&pm_mutex);
	120
	121	level = TEST_FIRST;
	122	for (s = &pm_tests[level]; level <= TEST_MAX; s++, level++)
	123	if (s && len == strlen(s) && !strncmp(buf, *s, len)) {
	124	pm_test_level = level;
	125	error = 0;
	126	break;
	127	}
	128
	129	mutex_unlock(&pm_mutex);
	130
	131	return error ? error : n;
	132	}
	133
	134	power_attr(pm_test);
091d71e0	135	#endif /* CONFIG_PM_DEBUG */
0e7d56e3	136
2a77c46d SL	137	#ifdef CONFIG_DEBUG_FS
	138	static char *suspend_step_name(enum suspend_stat_step step)
	139	{
	140	switch (step) {
	141	case SUSPEND_FREEZE:
	142	return "freeze";
	143	case SUSPEND_PREPARE:
	144	return "prepare";
	145	case SUSPEND_SUSPEND:
	146	return "suspend";
	147	case SUSPEND_SUSPEND_NOIRQ:
	148	return "suspend_noirq";
	149	case SUSPEND_RESUME_NOIRQ:
	150	return "resume_noirq";
	151	case SUSPEND_RESUME:
	152	return "resume";
	153	default:
	154	return "";
	155	}
	156	}
	157
	158	static int suspend_stats_show(struct seq_file s, void unused)
	159	{
	160	int i, index, last_dev, last_errno, last_step;
	161
	162	last_dev = suspend_stats.last_failed_dev + REC_FAILED_NUM - 1;
	163	last_dev %= REC_FAILED_NUM;
	164	last_errno = suspend_stats.last_failed_errno + REC_FAILED_NUM - 1;
	165	last_errno %= REC_FAILED_NUM;
	166	last_step = suspend_stats.last_failed_step + REC_FAILED_NUM - 1;
	167	last_step %= REC_FAILED_NUM;
	168	seq_printf(s, "%s: %d\n%s: %d\n%s: %d\n%s: %d\n"
	169	"%s: %d\n%s: %d\n%s: %d\n%s: %d\n",
	170	"success", suspend_stats.success,
	171	"fail", suspend_stats.fail,
	172	"failed_freeze", suspend_stats.failed_freeze,
	173	"failed_prepare", suspend_stats.failed_prepare,
	174	"failed_suspend", suspend_stats.failed_suspend,
	175	"failed_suspend_noirq",
	176	suspend_stats.failed_suspend_noirq,
	177	"failed_resume", suspend_stats.failed_resume,
	178	"failed_resume_noirq",
	179	suspend_stats.failed_resume_noirq);
	180	seq_printf(s, "failures:\n last_failed_dev:\t%-s\n",
	181	suspend_stats.failed_devs[last_dev]);
	182	for (i = 1; i < REC_FAILED_NUM; i++) {
	183	index = last_dev + REC_FAILED_NUM - i;
	184	index %= REC_FAILED_NUM;
	185	seq_printf(s, "\t\t\t%-s\n",
	186	suspend_stats.failed_devs[index]);
	187	}
	188	seq_printf(s, " last_failed_errno:\t%-d\n",
	189	suspend_stats.errno[last_errno]);
	190	for (i = 1; i < REC_FAILED_NUM; i++) {
	191	index = last_errno + REC_FAILED_NUM - i;
	192	index %= REC_FAILED_NUM;
	193	seq_printf(s, "\t\t\t%-d\n",
	194	suspend_stats.errno[index]);
	195	}
	196	seq_printf(s, " last_failed_step:\t%-s\n",
	197	suspend_step_name(
	198	suspend_stats.failed_steps[last_step]));
	199	for (i = 1; i < REC_FAILED_NUM; i++) {
	200	index = last_step + REC_FAILED_NUM - i;
201	index %= REC_FAILED_NUM;
202	seq_printf(s, "\t\t\t%-s\n",
203	suspend_step_name(
204	suspend_stats.failed_steps[index]));
205	}
206
207	return 0;
208	}
209
210	static int suspend_stats_open(struct inode inode, struct file file)
211	{
212	return single_open(file, suspend_stats_show, NULL);
213	}
214
215	static const struct file_operations suspend_stats_operations = {
216	.open = suspend_stats_open,
217	.read = seq_read,
218	.llseek = seq_lseek,
219	.release = single_release,
220	};
221
222	static int __init pm_debugfs_init(void)
223	{
224	debugfs_create_file("suspend_stats", S_IFREG \| S_IRUGO,
225	NULL, NULL, &suspend_stats_operations);
226	return 0;
227	}
228
229	late_initcall(pm_debugfs_init);
230	#endif /* CONFIG_DEBUG_FS */
231
ca123102 RW	232	#endif /* CONFIG_PM_SLEEP */
ca123102 RW	233
d76e15fb	234	struct kobject *power_kobj;
1da177e4 LT	235
	236	/**
	237	* state - control system power state.
	238	*
	239	* show() returns what states are supported, which is hard-coded to
	240	* 'standby' (Power-On Suspend), 'mem' (Suspend-to-RAM), and
	241	* 'disk' (Suspend-to-Disk).
	242	*
341d4166	243	* store() accepts one of those strings, translates it into the
1da177e4 LT	244	* proper enumerated value, and initiates a suspend transition.
1da177e4 LT	245	*/
386f275f KS	246	static ssize_t state_show(struct kobject kobj, struct kobj_attribute attr,
386f275f KS	247	char *buf)
1da177e4	248	{
296699de RW	249	char *s = buf;
296699de RW	250	#ifdef CONFIG_SUSPEND
1da177e4	251	int i;
1da177e4 LT	252
1da177e4 LT	253	for (i = 0; i < PM_SUSPEND_MAX; i++) {
123d3c13 PM	254	if (pm_states[i] && valid_state(i))
123d3c13 PM	255	s += sprintf(s,"%s ", pm_states[i]);
1da177e4	256	}
296699de	257	#endif
b0cb1a19	258	#ifdef CONFIG_HIBERNATION
a3d25c27 RW	259	s += sprintf(s, "%s\n", "disk");
	260	#else
	261	if (s != buf)
	262	/* convert the last space to a newline */
	263	*(s-1) = '\n';
	264	#endif
1da177e4 LT	265	return (s - buf);
	266	}
	267
386f275f KS	268	static ssize_t state_store(struct kobject kobj, struct kobj_attribute attr,
386f275f KS	269	const char *buf, size_t n)
1da177e4	270	{
296699de	271	#ifdef CONFIG_SUSPEND
1da177e4	272	suspend_state_t state = PM_SUSPEND_STANDBY;
3b364b8d	273	const char * const *s;
296699de	274	#endif
1da177e4	275	char *p;
1da177e4	276	int len;
296699de	277	int error = -EINVAL;
1da177e4 LT	278
	279	p = memchr(buf, '\n', n);
	280	len = p ? p - buf : n;
	281
a3d25c27	282	/* First, check if we are requested to hibernate */
8d98a690	283	if (len == 4 && !strncmp(buf, "disk", len)) {
a3d25c27	284	error = hibernate();
341d4166	285	goto Exit;
a3d25c27 RW	286	}
a3d25c27 RW	287
296699de	288	#ifdef CONFIG_SUSPEND
1da177e4	289	for (s = &pm_states[state]; state < PM_SUSPEND_MAX; s++, state++) {
8d98a690	290	if (s && len == strlen(s) && !strncmp(buf, *s, len))
1da177e4 LT	291	break;
1da177e4 LT	292	}
501a708f	293	if (state < PM_SUSPEND_MAX && *s) {
1da177e4	294	error = enter_state(state);
2a77c46d SL	295	if (error) {
	296	suspend_stats.fail++;
	297	dpm_save_failed_errno(error);
	298	} else
	299	suspend_stats.success++;
501a708f	300	}
296699de RW	301	#endif
	302
	303	Exit:
1da177e4 LT	304	return error ? error : n;
	305	}
	306
	307	power_attr(state);
	308
c125e96f RW	309	#ifdef CONFIG_PM_SLEEP
	310	/*
	311	* The 'wakeup_count' attribute, along with the functions defined in
	312	* drivers/base/power/wakeup.c, provides a means by which wakeup events can be
	313	* handled in a non-racy way.
	314	*
	315	* If a wakeup event occurs when the system is in a sleep state, it simply is
	316	* woken up. In turn, if an event that would wake the system up from a sleep
	317	* state occurs when it is undergoing a transition to that sleep state, the
	318	* transition should be aborted. Moreover, if such an event occurs when the
	319	* system is in the working state, an attempt to start a transition to the
	320	* given sleep state should fail during certain period after the detection of
	321	* the event. Using the 'state' attribute alone is not sufficient to satisfy
	322	* these requirements, because a wakeup event may occur exactly when 'state'
	323	* is being written to and may be delivered to user space right before it is
	324	* frozen, so the event will remain only partially processed until the system is
	325	* woken up by another event. In particular, it won't cause the transition to
	326	* a sleep state to be aborted.
	327	*
	328	* This difficulty may be overcome if user space uses 'wakeup_count' before
	329	* writing to 'state'. It first should read from 'wakeup_count' and store
	330	* the read value. Then, after carrying out its own preparations for the system
	331	* transition to a sleep state, it should write the stored value to
25985edc	332	* 'wakeup_count'. If that fails, at least one wakeup event has occurred since
c125e96f RW	333	* 'wakeup_count' was read and 'state' should not be written to. Otherwise, it
	334	* is allowed to write to 'state', but the transition will be aborted if there
	335	* are any wakeup events detected after 'wakeup_count' was written to.
	336	*/
	337
	338	static ssize_t wakeup_count_show(struct kobject *kobj,
	339	struct kobj_attribute *attr,
	340	char *buf)
	341	{
074037ec	342	unsigned int val;
c125e96f	343
074037ec	344	return pm_get_wakeup_count(&val) ? sprintf(buf, "%u\n", val) : -EINTR;
c125e96f RW	345	}
	346
	347	static ssize_t wakeup_count_store(struct kobject *kobj,
	348	struct kobj_attribute *attr,
	349	const char *buf, size_t n)
	350	{
074037ec	351	unsigned int val;
c125e96f	352
074037ec	353	if (sscanf(buf, "%u", &val) == 1) {
c125e96f RW	354	if (pm_save_wakeup_count(val))
	355	return n;
	356	}
	357	return -EINVAL;
	358	}
	359
	360	power_attr(wakeup_count);
	361	#endif /* CONFIG_PM_SLEEP */
	362
c5c6ba4e RW	363	#ifdef CONFIG_PM_TRACE
	364	int pm_trace_enabled;
	365
386f275f KS	366	static ssize_t pm_trace_show(struct kobject kobj, struct kobj_attribute attr,
386f275f KS	367	char *buf)
c5c6ba4e RW	368	{
	369	return sprintf(buf, "%d\n", pm_trace_enabled);
	370	}
	371
	372	static ssize_t
386f275f KS	373	pm_trace_store(struct kobject kobj, struct kobj_attribute attr,
386f275f KS	374	const char *buf, size_t n)
c5c6ba4e RW	375	{
	376	int val;
	377
	378	if (sscanf(buf, "%d", &val) == 1) {
	379	pm_trace_enabled = !!val;
	380	return n;
	381	}
	382	return -EINVAL;
	383	}
	384
	385	power_attr(pm_trace);
d33ac60b JH	386
	387	static ssize_t pm_trace_dev_match_show(struct kobject *kobj,
	388	struct kobj_attribute *attr,
	389	char *buf)
	390	{
	391	return show_trace_dev_match(buf, PAGE_SIZE);
	392	}
	393
	394	static ssize_t
	395	pm_trace_dev_match_store(struct kobject kobj, struct kobj_attribute attr,
	396	const char *buf, size_t n)
	397	{
	398	return -EINVAL;
	399	}
	400
	401	power_attr(pm_trace_dev_match);
	402
0e7d56e3	403	#endif /* CONFIG_PM_TRACE */
c5c6ba4e RW	404
	405	static struct attribute * g[] = {
	406	&state_attr.attr,
0e7d56e3	407	#ifdef CONFIG_PM_TRACE
c5c6ba4e	408	&pm_trace_attr.attr,
d33ac60b	409	&pm_trace_dev_match_attr.attr,
0e7d56e3	410	#endif
0e06b4a8 RW	411	#ifdef CONFIG_PM_SLEEP
0e06b4a8 RW	412	&pm_async_attr.attr,
c125e96f	413	&wakeup_count_attr.attr,
0e06b4a8	414	#ifdef CONFIG_PM_DEBUG
0e7d56e3	415	&pm_test_attr.attr,
0e06b4a8	416	#endif
0e7d56e3	417	#endif
c5c6ba4e RW	418	NULL,
c5c6ba4e RW	419	};
1da177e4 LT	420
	421	static struct attribute_group attr_group = {
	422	.attrs = g,
	423	};
	424
5e928f77 RW	425	#ifdef CONFIG_PM_RUNTIME
5e928f77 RW	426	struct workqueue_struct *pm_wq;
7b199ca2	427	EXPORT_SYMBOL_GPL(pm_wq);
5e928f77 RW	428
	429	static int __init pm_start_workqueue(void)
	430	{
58a69cb4	431	pm_wq = alloc_workqueue("pm", WQ_FREEZABLE, 0);
5e928f77 RW	432
	433	return pm_wq ? 0 : -ENOMEM;
	434	}
	435	#else
	436	static inline int pm_start_workqueue(void) { return 0; }
	437	#endif
	438
1da177e4 LT	439	static int __init pm_init(void)
1da177e4 LT	440	{
5e928f77 RW	441	int error = pm_start_workqueue();
	442	if (error)
	443	return error;
ac5c24ec	444	hibernate_image_size_init();
ddeb6487	445	hibernate_reserved_size_init();
d76e15fb GKH	446	power_kobj = kobject_create_and_add("power", NULL);
d76e15fb GKH	447	if (!power_kobj)
039a5dcd	448	return -ENOMEM;
d76e15fb	449	return sysfs_create_group(power_kobj, &attr_group);
1da177e4 LT	450	}
	451
	452	core_initcall(pm_init);