/*
 * 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)
{
        return (blocking_notifier_call_chain(&pm_chain_head, val, NULL)
                        == NOTIFY_BAD) ? -EINVAL : 0;
}

/* 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);