main.c

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/*
 * 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;

    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;
}
#else /* !CONFIG_PP_SLEEP_DEBUG */
static inline void pm_print_times_init(void) {}
#endif /* CONFIG_PM_SLEEP_DEBUG */

struct kobject *power_kobj;

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 suspend_state_t decode_state(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;

    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 (s = &pm_states[state]; state < PM_SUSPEND_MAX; s++, state++)
        if (*s && len == strlen(*s) && !strncmp(buf, *s, 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)
        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;
    }

 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", valid_state(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;

    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;
        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_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,
#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;
    error = sysfs_create_group(power_kobj, &attr_group);
    if (error)
        return error;
    pm_print_times_init();
    return pm_autosleep_init();
}

core_initcall(pm_init);