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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/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 "power.h"

BLOCKING_NOTIFIER_HEAD(pm_chain_head);

DEFINE_MUTEX(pm_mutex);

unsigned int pm_flags;

EXPORT_SYMBOL(pm_flags);

#ifdef CONFIG_SUSPEND

/* 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;

        error = pm_notifier_call_chain(PM_SUSPEND_PREPARE);

        if (error)

                goto Finish;

        pm_prepare_console();

        if (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:

        thaw_processes();

        pm_restore_console();

 Finish:

        pm_notifier_call_chain(PM_POST_SUSPEND);

        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;

        arch_suspend_disable_irqs();

        BUG_ON(!irqs_disabled());

        if ((error = device_power_down(PMSG_SUSPEND))) {

                printk(KERN_ERR "Some devices failed to power down\n");

                goto Done;

        }

        error = suspend_ops->enter(state);

        device_power_up();

 Done:

        arch_suspend_enable_irqs();

        BUG_ON(irqs_disabled());

        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;

        if (!suspend_ops)

                return -ENOSYS;

        if (suspend_ops->set_target) {

                error = suspend_ops->set_target(state);

                if (error)

                        return error;

        }

        suspend_console();

        error = device_suspend(PMSG_SUSPEND);

        if (error) {

                printk(KERN_ERR "Some devices failed to suspend\n");

                goto Resume_console;

        }

        if (suspend_ops->prepare) {

                error = suspend_ops->prepare();

                if (error)

                        goto Resume_devices;

        }

        error = disable_nonboot_cpus();

        if (!error)

                suspend_enter(state);

        enable_nonboot_cpus();

        if (suspend_ops->finish)

                suspend_ops->finish();

 Resume_devices:

        device_resume();

 Resume_console:

        resume_console();

        return error;

}

/**

 *      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)

{

        thaw_processes();

        pm_restore_console();

        pm_notifier_call_chain(PM_POST_SUSPEND);

}

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("Syncing filesystems ... ");

        sys_sync();

        printk("done.\n");

        pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]);

        if ((error = suspend_prepare()))

                goto Unlock;

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

        error = suspend_devices_and_enter(state);

        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 */

decl_subsys(power,NULL,NULL);

/**

 *      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 kset *kset, 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 kset *kset, 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 kset *kset, char *buf)

{

        return sprintf(buf, "%d\n", pm_trace_enabled);

}

static ssize_t

pm_trace_store(struct kset *kset, 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 struct attribute * g[] = {

        &state_attr.attr,

        &pm_trace_attr.attr,

        NULL,

};

#else

static struct attribute * g[] = {

        &state_attr.attr,

        NULL,

};

#endif /* CONFIG_PM_TRACE */

static struct attribute_group attr_group = {

        .attrs = g,

};

static int __init pm_init(void)

{

        int error = subsystem_register(&power_subsys);

        if (!error)

                error = sysfs_create_group(&power_subsys.kobj,&attr_group);

        return error;

}

core_initcall(pm_init);