allow coexistance of N build and AC build.

[tomato.git] / release / src-rt-6.x / linux / linux-2.6 / kernel / power / 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/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 "power.h"

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

DEFINE_MUTEX(pm_mutex);

struct pm_ops *pm_ops;

/**
 *      pm_set_ops - Set the global power method table. 
 *      @ops:   Pointer to ops structure.
 */

void pm_set_ops(struct pm_ops * ops)
{
        mutex_lock(&pm_mutex);
        pm_ops = ops;
        mutex_unlock(&pm_mutex);
}

/**
 * pm_valid_only_mem - generic memory-only valid callback
 *
 * pm_ops 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 pm_valid_only_mem(suspend_state_t state)
{
        return state == PM_SUSPEND_MEM;
}


static inline void pm_finish(suspend_state_t state)
{
        if (pm_ops->finish)
                pm_ops->finish(state);
}

/**
 *      suspend_prepare - Do prep work before entering low-power state.
 *      @state:         State we're entering.
 *
 *      This is common code that is called for each state that we're 
 *      entering. Allocate a console, stop all processes, then make sure
 *      the platform can enter the requested state.
 */

static int suspend_prepare(suspend_state_t state)
{
        int error;
        unsigned int free_pages;

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

        pm_prepare_console();

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

        if ((free_pages = global_page_state(NR_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");
                        goto Thaw;
                }
        }

        if (pm_ops->set_target) {
                error = pm_ops->set_target(state);
                if (error)
                        goto Thaw;
        }
        suspend_console();
        error = device_suspend(PMSG_SUSPEND);
        if (error) {
                printk(KERN_ERR "Some devices failed to suspend\n");
                goto Resume_console;
        }
        if (pm_ops->prepare) {
                if ((error = pm_ops->prepare(state)))
                        goto Resume_devices;
        }

        error = disable_nonboot_cpus();
        if (!error)
                return 0;

        enable_nonboot_cpus();
        pm_finish(state);
 Resume_devices:
        device_resume();
 Resume_console:
        resume_console();
 Thaw:
        thaw_processes();
        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();
}

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 = pm_ops->enter(state);
        device_power_up();
 Done:
        arch_suspend_enable_irqs();
        BUG_ON(irqs_disabled());
        return error;
}


/**
 *      suspend_finish - Do final work before exiting suspend sequence.
 *      @state:         State we're coming out of.
 *
 *      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(suspend_state_t state)
{
        enable_nonboot_cpus();
        pm_finish(state);
        device_resume();
        resume_console();
        thaw_processes();
        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 (!pm_ops || !pm_ops->valid || !pm_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;

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

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

        pr_debug("PM: Finishing wakeup.\n");
        suspend_finish(state);
 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);

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)
{
        int i;
        char * s = buf;

        for (i = 0; i < PM_SUSPEND_MAX; i++) {
                if (pm_states[i] && valid_state(i))
                        s += sprintf(s,"%s ", pm_states[i]);
        }
#ifdef CONFIG_SOFTWARE_SUSPEND
        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)
{
        suspend_state_t state = PM_SUSPEND_STANDBY;
        const char * const *s;
        char *p;
        int error;
        int len;

        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();
                return error ? error : n;
        }

        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);
        else
                error = -EINVAL;
        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);