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/pm-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 nr_to_call, int *nr_calls)
{
int ret;
ret = __blocking_notifier_call_chain(&pm_chain_head, val, NULL,
nr_to_call, nr_calls);
return notifier_to_errno(ret);
}
int pm_notifier_call_chain(unsigned long val)
{
return __pm_notifier_call_chain(val, -1, NULL);
}
/* 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 (kstrtoul(buf, 10, &val))
return -EINVAL;
if (val > 1)
return -EINVAL;
pm_async_enabled = val;
return n;
}
power_attr(pm_async);
#ifdef CONFIG_SUSPEND
static ssize_t mem_sleep_show(struct kobject *kobj, struct kobj_attribute *attr,
char *buf)
{
char *s = buf;
suspend_state_t i;
for (i = PM_SUSPEND_MIN; i < PM_SUSPEND_MAX; i++)
if (mem_sleep_states[i]) {
const char *label = mem_sleep_states[i];
if (mem_sleep_current == i)
s += sprintf(s, "[%s] ", label);
else
s += sprintf(s, "%s ", label);
}
/* Convert the last space to a newline if needed. */
if (s != buf)
*(s-1) = '\n';
return (s - buf);
}
static suspend_state_t decode_suspend_state(const char *buf, size_t n)
{
suspend_state_t state;
char *p;
int len;
p = memchr(buf, '\n', n);
len = p ? p - buf : n;
for (state = PM_SUSPEND_MIN; state < PM_SUSPEND_MAX; state++) {
const char *label = mem_sleep_states[state];
if (label && len == strlen(label) && !strncmp(buf, label, len))
return state;
}
return PM_SUSPEND_ON;
}
static ssize_t mem_sleep_store(struct kobject *kobj, struct kobj_attribute *attr,
const char *buf, size_t n)
{
suspend_state_t state;
int error;
error = pm_autosleep_lock();
if (error)
return error;
if (pm_autosleep_state() > PM_SUSPEND_ON) {
error = -EBUSY;
goto out;
}
state = decode_suspend_state(buf, n);
if (state < PM_SUSPEND_MAX && state > PM_SUSPEND_ON)
mem_sleep_current = state;
else
error = -EINVAL;
out:
pm_autosleep_unlock();
return error ? error : n;
}
power_attr(mem_sleep);
#endif /* CONFIG_SUSPEND */
#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;
lock_system_sleep();
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;
}
unlock_system_sleep();
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%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_late",
suspend_stats.failed_suspend_late,
"failed_suspend_noirq",
suspend_stats.failed_suspend_noirq,
"failed_resume", suspend_stats.failed_resume,
"failed_resume_early",
suspend_stats.failed_resume_early,
"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 */
#ifdef CONFIG_PM_SLEEP_DEBUG
/*
* pm_print_times: print time taken by devices to suspend and resume.
*
* show() returns whether printing of suspend and resume times is enabled.
* store() accepts 0 or 1. 0 disables printing and 1 enables it.
*/
bool pm_print_times_enabled;
static ssize_t pm_print_times_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
return sprintf(buf, "%d\n", pm_print_times_enabled);
}
static ssize_t pm_print_times_store(struct kobject *kobj,
struct kobj_attribute *attr,
const char *buf, size_t n)
{
unsigned long val;
if (kstrtoul(buf, 10, &val))
return -EINVAL;
if (val > 1)
return -EINVAL;
pm_print_times_enabled = !!val;
return n;
}
power_attr(pm_print_times);
static inline void pm_print_times_init(void)
{
pm_print_times_enabled = !!initcall_debug;
}
static ssize_t pm_wakeup_irq_show(struct kobject *kobj,
struct kobj_attribute *attr,
char *buf)
{
return pm_wakeup_irq ? sprintf(buf, "%u\n", pm_wakeup_irq) : -ENODATA;
}
power_attr_ro(pm_wakeup_irq);
#else /* !CONFIG_PM_SLEEP_DEBUG */
static inline void pm_print_times_init(void) {}
#endif /* CONFIG_PM_SLEEP_DEBUG */
struct kobject *power_kobj;
/**
* state - control system sleep states.
*
* show() returns available sleep state labels, which may be "mem", "standby",
* "freeze" and "disk" (hibernation). See Documentation/power/states.txt for a
* description of what they mean.
*
* 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
suspend_state_t i;
for (i = PM_SUSPEND_MIN; i < PM_SUSPEND_MAX; i++)
if (pm_states[i])
s += sprintf(s,"%s ", pm_states[i]);
#endif
if (hibernation_available())
s += sprintf(s, "disk ");
if (s != buf)
/* convert the last space to a newline */
*(s-1) = '\n';
return (s - buf);
}
static suspend_state_t decode_state(const char *buf, size_t n)
{
#ifdef CONFIG_SUSPEND
suspend_state_t state;
#endif
char *p;
int len;
p = memchr(buf, '\n', n);
len = p ? p - buf : n;
/* Check hibernation first. */
if (len == 4 && !strncmp(buf, "disk", len))
return PM_SUSPEND_MAX;
#ifdef CONFIG_SUSPEND
for (state = PM_SUSPEND_MIN; state < PM_SUSPEND_MAX; state++) {
const char *label = pm_states[state];
if (label && len == strlen(label) && !strncmp(buf, label, len))
return state;
}
#endif
return PM_SUSPEND_ON;
}
static ssize_t state_store(struct kobject *kobj, struct kobj_attribute *attr,
const char *buf, size_t n)
{
suspend_state_t state;
int error;
error = pm_autosleep_lock();
if (error)
return error;
if (pm_autosleep_state() > PM_SUSPEND_ON) {
error = -EBUSY;
goto out;
}
state = decode_state(buf, n);
if (state < PM_SUSPEND_MAX) {
if (state == PM_SUSPEND_MEM)
state = mem_sleep_current;
error = pm_suspend(state);
} else if (state == PM_SUSPEND_MAX) {
error = hibernate();
} else {
error = -EINVAL;
}
out:
pm_autosleep_unlock();
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, true) ?
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;
int error;
error = pm_autosleep_lock();
if (error)
return error;
if (pm_autosleep_state() > PM_SUSPEND_ON) {
error = -EBUSY;
goto out;
}
error = -EINVAL;
if (sscanf(buf, "%u", &val) == 1) {
if (pm_save_wakeup_count(val))
error = n;
else
pm_print_active_wakeup_sources();
}
out:
pm_autosleep_unlock();
return error;
}
power_attr(wakeup_count);
#ifdef CONFIG_PM_AUTOSLEEP
static ssize_t autosleep_show(struct kobject *kobj,
struct kobj_attribute *attr,
char *buf)
{
suspend_state_t state = pm_autosleep_state();
if (state == PM_SUSPEND_ON)
return sprintf(buf, "off\n");
#ifdef CONFIG_SUSPEND
if (state < PM_SUSPEND_MAX)
return sprintf(buf, "%s\n", pm_states[state] ?
pm_states[state] : "error");
#endif
#ifdef CONFIG_HIBERNATION
return sprintf(buf, "disk\n");
#else
return sprintf(buf, "error");
#endif
}
static ssize_t autosleep_store(struct kobject *kobj,
struct kobj_attribute *attr,
const char *buf, size_t n)
{
suspend_state_t state = decode_state(buf, n);
int error;
if (state == PM_SUSPEND_ON
&& strcmp(buf, "off") && strcmp(buf, "off\n"))
return -EINVAL;
if (state == PM_SUSPEND_MEM)
state = mem_sleep_current;
error = pm_autosleep_set_state(state);
return error ? error : n;
}
power_attr(autosleep);
#endif /* CONFIG_PM_AUTOSLEEP */
#ifdef CONFIG_PM_WAKELOCKS
static ssize_t wake_lock_show(struct kobject *kobj,
struct kobj_attribute *attr,
char *buf)
{
return pm_show_wakelocks(buf, true);
}
static ssize_t wake_lock_store(struct kobject *kobj,
struct kobj_attribute *attr,
const char *buf, size_t n)
{
int error = pm_wake_lock(buf);
return error ? error : n;
}
power_attr(wake_lock);
static ssize_t wake_unlock_show(struct kobject *kobj,
struct kobj_attribute *attr,
char *buf)
{
return pm_show_wakelocks(buf, false);
}
static ssize_t wake_unlock_store(struct kobject *kobj,
struct kobj_attribute *attr,
const char *buf, size_t n)
{
int error = pm_wake_unlock(buf);
return error ? error : n;
}
power_attr(wake_unlock);
#endif /* CONFIG_PM_WAKELOCKS */
#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;
if (pm_trace_enabled) {
pr_warn("PM: Enabling pm_trace changes system date and time during resume.\n"
"PM: Correct system time has to be restored manually after resume.\n");
}
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);
}
power_attr_ro(pm_trace_dev_match);
#endif /* CONFIG_PM_TRACE */
#ifdef CONFIG_FREEZER
static ssize_t pm_freeze_timeout_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
return sprintf(buf, "%u\n", freeze_timeout_msecs);
}
static ssize_t pm_freeze_timeout_store(struct kobject *kobj,
struct kobj_attribute *attr,
const char *buf, size_t n)
{
unsigned long val;
if (kstrtoul(buf, 10, &val))
return -EINVAL;
freeze_timeout_msecs = val;
return n;
}
power_attr(pm_freeze_timeout);
#endif /* CONFIG_FREEZER*/
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_SUSPEND
&mem_sleep_attr.attr,
#endif
#ifdef CONFIG_PM_AUTOSLEEP
&autosleep_attr.attr,
#endif
#ifdef CONFIG_PM_WAKELOCKS
&wake_lock_attr.attr,
&wake_unlock_attr.attr,
#endif
#ifdef CONFIG_PM_DEBUG
&pm_test_attr.attr,
#endif
#ifdef CONFIG_PM_SLEEP_DEBUG
&pm_print_times_attr.attr,
&pm_wakeup_irq_attr.attr,
#endif
#endif
#ifdef CONFIG_FREEZER
&pm_freeze_timeout_attr.attr,
#endif
NULL,
};
static const struct attribute_group attr_group = {
.attrs = g,
};
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;
}
static int __init pm_init(void)
{
int error = pm_start_workqueue();
if (error)
return error;
hibernate_image_size_init();
hibernate_reserved_size_init();
pm_states_init();
power_kobj = kobject_create_and_add("power", NULL);
if (!power_kobj)
return -ENOMEM;
error = sysfs_create_group(power_kobj, &attr_group);
if (error)
return error;
pm_print_times_init();
return pm_autosleep_init();
}
core_initcall(pm_init);