/*
 * 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/module.h>
#include <linux/suspend.h>
#include <linux/kobject.h>
#include <linux/string.h>
#include <linux/delay.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/console.h>
#include <linux/cpu.h>
#include <linux/resume-trace.h>
#include <linux/freezer.h>
#include <linux/vmstat.h>
#include <linux/syscalls.h>
#include <linux/ftrace.h>

#include "power.h"

DEFINE_MUTEX(pm_mutex);

unsigned int pm_flags;
EXPORT_SYMBOL(pm_flags);

#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;
}

#ifdef CONFIG_PM_DEBUG
int pm_test_level = TEST_NONE;

static int suspend_test(int level)
{
        if (pm_test_level == level) {
                printk(KERN_INFO "suspend debug: Waiting for 5 seconds.\n");
                mdelay(5000);
                return 1;
        }
        return 0;
}

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);
#else /* !CONFIG_PM_DEBUG */
static inline int suspend_test(int level) { return 0; }
#endif /* !CONFIG_PM_DEBUG */

#endif /* CONFIG_PM_SLEEP */

#ifdef CONFIG_SUSPEND

#ifdef CONFIG_PM_TEST_SUSPEND

/*
 * We test the system suspend code by setting an RTC wakealarm a short
 * time in the future, then suspending.  Suspending the devices won't
 * normally take long ... some systems only need a few milliseconds.
 *
 * The time it takes is system-specific though, so when we test this
 * during system bootup we allow a LOT of time.
 */
#define TEST_SUSPEND_SECONDS    5

static unsigned long suspend_test_start_time;

static void suspend_test_start(void)
{
        /* FIXME Use better timebase than "jiffies", ideally a clocksource.
         * What we want is a hardware counter that will work correctly even
         * during the irqs-are-off stages of the suspend/resume cycle...
         */
        suspend_test_start_time = jiffies;
}

static void suspend_test_finish(const char *label)
{
        long nj = jiffies - suspend_test_start_time;
        unsigned msec;

        msec = jiffies_to_msecs(abs(nj));
        pr_info("PM: %s took %d.%03d seconds\n", label,
                        msec / 1000, msec % 1000);

        /* Warning on suspend means the RTC alarm period needs to be
         * larger -- the system was sooo slooowwww to suspend that the
         * alarm (should have) fired before the system went to sleep!
         *
         * Warning on either suspend or resume also means the system
         * has some performance issues.  The stack dump of a WARN_ON
         * is more likely to get the right attention than a printk...
         */
        WARN_ON(msec > (TEST_SUSPEND_SECONDS * 1000));
}

#else

static void suspend_test_start(void)
{
}

static void suspend_test_finish(const char *label)
{
}

#endif

/* This is just an arbitrary number */
#define FREE_PAGE_NUMBER (100)

static struct platform_suspend_ops *suspend_ops;

/**
 *      suspend_set_ops - Set the global suspend method table.
 *      @ops:   Pointer to ops structure.
 */

void suspend_set_ops(struct platform_suspend_ops *ops)
{
        mutex_lock(&pm_mutex);
        suspend_ops = ops;
        mutex_unlock(&pm_mutex);
}

/**
 * suspend_valid_only_mem - generic memory-only valid callback
 *
 * Platform drivers that implement mem suspend only and only need
 * to check for that in their .valid callback can use this instead
 * of rolling their own .valid callback.
 */
int suspend_valid_only_mem(suspend_state_t state)
{
        return state == PM_SUSPEND_MEM;
}

/**
 *      suspend_prepare - Do prep work before entering low-power state.
 *
 *      This is common code that is called for each state that we're entering.
 *      Run suspend notifiers, allocate a console and stop all processes.
 */
static int suspend_prepare(void)
{
        int error;
        unsigned int free_pages;

        if (!suspend_ops || !suspend_ops->enter)
                return -EPERM;

        pm_prepare_console();

        error = pm_notifier_call_chain(PM_SUSPEND_PREPARE);
        if (error)
                goto Finish;

        if (suspend_freeze_processes()) {
                error = -EAGAIN;
                goto Thaw;
        }

        free_pages = global_page_state(NR_FREE_PAGES);
        if (free_pages < FREE_PAGE_NUMBER) {
                pr_debug("PM: free some memory\n");
                shrink_all_memory(FREE_PAGE_NUMBER - free_pages);
                if (nr_free_pages() < FREE_PAGE_NUMBER) {
                        error = -ENOMEM;
                        printk(KERN_ERR "PM: No enough memory\n");
                }
        }
        if (!error)
                return 0;

 Thaw:
        suspend_thaw_processes();
 Finish:
        pm_notifier_call_chain(PM_POST_SUSPEND);
        pm_restore_console();
        return error;
}

/* default implementation */
void __attribute__ ((weak)) arch_suspend_disable_irqs(void)
{
        local_irq_disable();
}

/* default implementation */
void __attribute__ ((weak)) arch_suspend_enable_irqs(void)
{
        local_irq_enable();
}

/**
 *      suspend_enter - enter the desired system sleep state.
 *      @state:         state to enter
 *
 *      This function should be called after devices have been suspended.
 */
static int suspend_enter(suspend_state_t state)
{
        int error = 0;

        device_pm_lock();
        arch_suspend_disable_irqs();
        BUG_ON(!irqs_disabled());

        if ((error = device_power_down(PMSG_SUSPEND))) {
                printk(KERN_ERR "PM: Some devices failed to power down\n");
                goto Done;
        }

        if (!suspend_test(TEST_CORE))
                error = suspend_ops->enter(state);

        device_power_up(PMSG_RESUME);
 Done:
        arch_suspend_enable_irqs();
        BUG_ON(irqs_disabled());
        device_pm_unlock();
        return error;
}

/**
 *      suspend_devices_and_enter - suspend devices and enter the desired system
 *                                  sleep state.
 *      @state:           state to enter
 */
int suspend_devices_and_enter(suspend_state_t state)
{
        int error, ftrace_save;

        if (!suspend_ops)
                return -ENOSYS;

        if (suspend_ops->begin) {
                error = suspend_ops->begin(state);
                if (error)
                        goto Close;
        }
        suspend_console();
        ftrace_save = __ftrace_enabled_save();
        suspend_test_start();
        error = device_suspend(PMSG_SUSPEND);
        if (error) {
                printk(KERN_ERR "PM: Some devices failed to suspend\n");
                goto Recover_platform;
        }
        suspend_test_finish("suspend devices");
        if (suspend_test(TEST_DEVICES))
                goto Recover_platform;

        if (suspend_ops->prepare) {
                error = suspend_ops->prepare();
                if (error)
                        goto Resume_devices;
        }

        if (suspend_test(TEST_PLATFORM))
                goto Finish;

        error = disable_nonboot_cpus();
        if (!error && !suspend_test(TEST_CPUS))
                suspend_enter(state);

        enable_nonboot_cpus();
 Finish:
        if (suspend_ops->finish)
                suspend_ops->finish();
 Resume_devices:
        suspend_test_start();
        device_resume(PMSG_RESUME);
        suspend_test_finish("resume devices");
        __ftrace_enabled_restore(ftrace_save);
        resume_console();
 Close:
        if (suspend_ops->end)
                suspend_ops->end();
        return error;

 Recover_platform:
        if (suspend_ops->recover)
                suspend_ops->recover();
        goto Resume_devices;
}

/**
 *      suspend_finish - Do final work before exiting suspend sequence.
 *
 *      Call platform code to clean up, restart processes, and free the 
 *      console that we've allocated. This is not called for suspend-to-disk.
 */
static void suspend_finish(void)
{
        suspend_thaw_processes();
        pm_notifier_call_chain(PM_POST_SUSPEND);
        pm_restore_console();
}




static const char * const pm_states[PM_SUSPEND_MAX] = {
        [PM_SUSPEND_STANDBY]    = "standby",
        [PM_SUSPEND_MEM]        = "mem",
};

static inline int valid_state(suspend_state_t state)
{
        /* All states need lowlevel support and need to be valid
         * to the lowlevel implementation, no valid callback
         * implies that none are valid. */
        if (!suspend_ops || !suspend_ops->valid || !suspend_ops->valid(state))
                return 0;
        return 1;
}


/**
 *      enter_state - Do common work of entering low-power state.
 *      @state:         pm_state structure for state we're entering.
 *
 *      Make sure we're the only ones trying to enter a sleep state. Fail
 *      if someone has beat us to it, since we don't want anything weird to
 *      happen when we wake up.
 *      Then, do the setup for suspend, enter the state, and cleaup (after
 *      we've woken up).
 */
static int enter_state(suspend_state_t state)
{
        int error;

        if (!valid_state(state))
                return -ENODEV;

        if (!mutex_trylock(&pm_mutex))
                return -EBUSY;

        printk(KERN_INFO "PM: Syncing filesystems ... ");
        sys_sync();
        printk("done.\n");

        pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]);
        error = suspend_prepare();
        if (error)
                goto Unlock;

        if (suspend_test(TEST_FREEZER))
                goto Finish;

        pr_debug("PM: Entering %s sleep\n", pm_states[state]);
        error = suspend_devices_and_enter(state);

 Finish:
        pr_debug("PM: Finishing wakeup.\n");
        suspend_finish();
 Unlock:
        mutex_unlock(&pm_mutex);
        return error;
}


/**
 *      pm_suspend - Externally visible function for suspending system.
 *      @state:         Enumerated value of state to enter.
 *
 *      Determine whether or not value is within range, get state 
 *      structure, and enter (above).
 */

int pm_suspend(suspend_state_t state)
{
        if (state > PM_SUSPEND_ON && state <= PM_SUSPEND_MAX)
                return enter_state(state);
        return -EINVAL;
}

EXPORT_SYMBOL(pm_suspend);

#endif /* CONFIG_SUSPEND */

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_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);
#endif /* CONFIG_PM_TRACE */

static struct attribute * g[] = {
        &state_attr.attr,
#ifdef CONFIG_PM_TRACE
        &pm_trace_attr.attr,
#endif
#if defined(CONFIG_PM_SLEEP) && defined(CONFIG_PM_DEBUG)
        &pm_test_attr.attr,
#endif
        NULL,
};

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


static int __init pm_init(void)
{
        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);


#ifdef CONFIG_PM_TEST_SUSPEND

#include <linux/rtc.h>

/*
 * To test system suspend, we need a hands-off mechanism to resume the
 * system.  RTCs wake alarms are a common self-contained mechanism.
 */

static void __init test_wakealarm(struct rtc_device *rtc, suspend_state_t state)
{
        static char err_readtime[] __initdata =
                KERN_ERR "PM: can't read %s time, err %d\n";
        static char err_wakealarm [] __initdata =
                KERN_ERR "PM: can't set %s wakealarm, err %d\n";
        static char err_suspend[] __initdata =
                KERN_ERR "PM: suspend test failed, error %d\n";
        static char info_test[] __initdata =
                KERN_INFO "PM: test RTC wakeup from '%s' suspend\n";

        unsigned long           now;
        struct rtc_wkalrm       alm;
        int                     status;

        /* this may fail if the RTC hasn't been initialized */
        status = rtc_read_time(rtc, &alm.time);
        if (status < 0) {
                printk(err_readtime, rtc->dev.bus_id, status);
                return;
        }
        rtc_tm_to_time(&alm.time, &now);

        memset(&alm, 0, sizeof alm);
        rtc_time_to_tm(now + TEST_SUSPEND_SECONDS, &alm.time);
        alm.enabled = true;

        status = rtc_set_alarm(rtc, &alm);
        if (status < 0) {
                printk(err_wakealarm, rtc->dev.bus_id, status);
                return;
        }

        if (state == PM_SUSPEND_MEM) {
                printk(info_test, pm_states[state]);
                status = pm_suspend(state);
                if (status == -ENODEV)
                        state = PM_SUSPEND_STANDBY;
        }
        if (state == PM_SUSPEND_STANDBY) {
                printk(info_test, pm_states[state]);
                status = pm_suspend(state);
        }
        if (status < 0)
                printk(err_suspend, status);

        /* Some platforms can't detect that the alarm triggered the
         * wakeup, or (accordingly) disable it after it afterwards.
         * It's supposed to give oneshot behavior; cope.
         */
        alm.enabled = false;
        rtc_set_alarm(rtc, &alm);
}

static int __init has_wakealarm(struct device *dev, void *name_ptr)
{
        struct rtc_device *candidate = to_rtc_device(dev);

        if (!candidate->ops->set_alarm)
                return 0;
        if (!device_may_wakeup(candidate->dev.parent))
                return 0;

        *(char **)name_ptr = dev->bus_id;
        return 1;
}

/*
 * Kernel options like "test_suspend=mem" force suspend/resume sanity tests
 * at startup time.  They're normally disabled, for faster boot and because
 * we can't know which states really work on this particular system.
 */
static suspend_state_t test_state __initdata = PM_SUSPEND_ON;

static char warn_bad_state[] __initdata =
        KERN_WARNING "PM: can't test '%s' suspend state\n";

static int __init setup_test_suspend(char *value)
{
        unsigned i;

        /* "=mem" ==> "mem" */
        value++;
        for (i = 0; i < PM_SUSPEND_MAX; i++) {
                if (!pm_states[i])
                        continue;
                if (strcmp(pm_states[i], value) != 0)
                        continue;
                test_state = (__force suspend_state_t) i;
                return 0;
        }
        printk(warn_bad_state, value);
        return 0;
}
__setup("test_suspend", setup_test_suspend);

static int __init test_suspend(void)
{
        static char             warn_no_rtc[] __initdata =
                KERN_WARNING "PM: no wakealarm-capable RTC driver is ready\n";

        char                    *pony = NULL;
        struct rtc_device       *rtc = NULL;

        /* PM is initialized by now; is that state testable? */
        if (test_state == PM_SUSPEND_ON)
                goto done;
        if (!valid_state(test_state)) {
                printk(warn_bad_state, pm_states[test_state]);
                goto done;
        }

        /* RTCs have initialized by now too ... can we use one? */
        class_find_device(rtc_class, NULL, &pony, has_wakealarm);
        if (pony)
                rtc = rtc_class_open(pony);
        if (!rtc) {
                printk(warn_no_rtc);
                goto done;
        }

        /* go for it */
        test_wakealarm(rtc, test_state);
        rtc_class_close(rtc);
done:
        return 0;
}
late_initcall(test_suspend);

#endif /* CONFIG_PM_TEST_SUSPEND */