disk.c

linux 内核源代码

/*
 * kernel/power/disk.c - Suspend-to-disk support.
 *
 * Copyright (c) 2003 Patrick Mochel
 * Copyright (c) 2003 Open Source Development Lab
 * Copyright (c) 2004 Pavel Machek <[e-mail]>
 *
 * This file is released under the GPLv2.
 *
 */

#include <linux/suspend.h>
#include <linux/syscalls.h>
#include <linux/reboot.h>
#include <linux/string.h>
#include <linux/device.h>
#include <linux/delay.h>
#include <linux/fs.h>
#include <linux/mount.h>
#include <linux/pm.h>
#include <linux/console.h>
#include <linux/cpu.h>
#include <linux/freezer.h>

#include "power.h"


static int noresume = 0;
char resume_file[256] = CONFIG_PM_STD_PARTITION;
dev_t swsusp_resume_device;
sector_t swsusp_resume_block;

enum {
	HIBERNATION_INVALID,
	HIBERNATION_PLATFORM,
	HIBERNATION_TEST,
	HIBERNATION_TESTPROC,
	HIBERNATION_SHUTDOWN,
	HIBERNATION_REBOOT,
	/* keep last */
	__HIBERNATION_AFTER_LAST
};
#define HIBERNATION_MAX (__HIBERNATION_AFTER_LAST-1)
#define HIBERNATION_FIRST (HIBERNATION_INVALID + 1)

static int hibernation_mode = HIBERNATION_SHUTDOWN;

static struct platform_hibernation_ops *hibernation_ops;

/**
 * hibernation_set_ops - set the global hibernate operations
 * @ops: the hibernation operations to use in subsequent hibernation transitions
 */

void hibernation_set_ops(struct platform_hibernation_ops *ops)
{
	if (ops && !(ops->start && ops->pre_snapshot && ops->finish
	    && ops->prepare && ops->enter && ops->pre_restore
	    && ops->restore_cleanup)) {
		WARN_ON(1);
		return;
	}
	mutex_lock(&pm_mutex);
	hibernation_ops = ops;
	if (ops)
		hibernation_mode = HIBERNATION_PLATFORM;
	else if (hibernation_mode == HIBERNATION_PLATFORM)
		hibernation_mode = HIBERNATION_SHUTDOWN;

	mutex_unlock(&pm_mutex);
}

/**
 *	platform_start - tell the platform driver that we're starting
 *	hibernation
 */

static int platform_start(int platform_mode)
{
	return (platform_mode && hibernation_ops) ?
		hibernation_ops->start() : 0;
}

/**
 *	platform_pre_snapshot - prepare the machine for hibernation using the
 *	platform driver if so configured and return an error code if it fails
 */

static int platform_pre_snapshot(int platform_mode)
{
	return (platform_mode && hibernation_ops) ?
		hibernation_ops->pre_snapshot() : 0;
}

/**
 *	platform_leave - prepare the machine for switching to the normal mode
 *	of operation using the platform driver (called with interrupts disabled)
 */

static void platform_leave(int platform_mode)
{
	if (platform_mode && hibernation_ops)
		hibernation_ops->leave();
}

/**
 *	platform_finish - switch the machine to the normal mode of operation
 *	using the platform driver (must be called after platform_prepare())
 */

static void platform_finish(int platform_mode)
{
	if (platform_mode && hibernation_ops)
		hibernation_ops->finish();
}

/**
 *	platform_pre_restore - prepare the platform for the restoration from a
 *	hibernation image.  If the restore fails after this function has been
 *	called, platform_restore_cleanup() must be called.
 */

static int platform_pre_restore(int platform_mode)
{
	return (platform_mode && hibernation_ops) ?
		hibernation_ops->pre_restore() : 0;
}

/**
 *	platform_restore_cleanup - switch the platform to the normal mode of
 *	operation after a failing restore.  If platform_pre_restore() has been
 *	called before the failing restore, this function must be called too,
 *	regardless of the result of platform_pre_restore().
 */

static void platform_restore_cleanup(int platform_mode)
{
	if (platform_mode && hibernation_ops)
		hibernation_ops->restore_cleanup();
}

/**
 *	create_image - freeze devices that need to be frozen with interrupts
 *	off, create the hibernation image and thaw those devices.  Control
 *	reappears in this routine after a restore.
 */

int create_image(int platform_mode)
{
	int error;

	error = arch_prepare_suspend();
	if (error)
		return error;

	local_irq_disable();
	/* At this point, device_suspend() has been called, but *not*
	 * device_power_down(). We *must* call device_power_down() now.
	 * Otherwise, drivers for some devices (e.g. interrupt controllers)
	 * become desynchronized with the actual state of the hardware
	 * at resume time, and evil weirdness ensues.
	 */
	error = device_power_down(PMSG_FREEZE);
	if (error) {
		printk(KERN_ERR "Some devices failed to power down, "
			KERN_ERR "aborting suspend\n");
		goto Enable_irqs;
	}

	save_processor_state();
	error = swsusp_arch_suspend();
	if (error)
		printk(KERN_ERR "Error %d while creating the image\n", error);
	/* Restore control flow magically appears here */
	restore_processor_state();
	if (!in_suspend)
		platform_leave(platform_mode);
	/* NOTE:  device_power_up() is just a resume() for devices
	 * that suspended with irqs off ... no overall powerup.
	 */
	device_power_up();
 Enable_irqs:
	local_irq_enable();
	return error;
}

/**
 *	hibernation_snapshot - quiesce devices and create the hibernation
 *	snapshot image.
 *	@platform_mode - if set, use the platform driver, if available, to
 *			 prepare the platform frimware for the power transition.
 *
 *	Must be called with pm_mutex held
 */

int hibernation_snapshot(int platform_mode)
{
	int error;

	/* Free memory before shutting down devices. */
	error = swsusp_shrink_memory();
	if (error)
		return error;

	error = platform_start(platform_mode);
	if (error)
		return error;

	suspend_console();
	error = device_suspend(PMSG_FREEZE);
	if (error)
		goto Resume_console;

	error = platform_pre_snapshot(platform_mode);
	if (error)
		goto Resume_devices;

	error = disable_nonboot_cpus();
	if (!error) {
		if (hibernation_mode != HIBERNATION_TEST) {
			in_suspend = 1;
			error = create_image(platform_mode);
			/* Control returns here after successful restore */
		} else {
			printk("swsusp debug: Waiting for 5 seconds.\n");
			mdelay(5000);
		}
	}
	enable_nonboot_cpus();
 Resume_devices:
	platform_finish(platform_mode);
	device_resume();
 Resume_console:
	resume_console();
	return error;
}

/**
 *	hibernation_restore - quiesce devices and restore the hibernation
 *	snapshot image.  If successful, control returns in hibernation_snaphot()
 *	@platform_mode - if set, use the platform driver, if available, to
 *			 prepare the platform frimware for the transition.
 *
 *	Must be called with pm_mutex held
 */

int hibernation_restore(int platform_mode)
{
	int error;

	pm_prepare_console();
	suspend_console();
	error = device_suspend(PMSG_PRETHAW);
	if (error)
		goto Finish;

	error = platform_pre_restore(platform_mode);
	if (!error) {
		error = disable_nonboot_cpus();
		if (!error)
			error = swsusp_resume();
		enable_nonboot_cpus();
	}
	platform_restore_cleanup(platform_mode);
	device_resume();
 Finish:
	resume_console();
	pm_restore_console();
	return error;
}

/**
 *	hibernation_platform_enter - enter the hibernation state using the
 *	platform driver (if available)
 */

int hibernation_platform_enter(void)
{
	int error;

	if (!hibernation_ops)
		return -ENOSYS;

	/*
	 * We have cancelled the power transition by running
	 * hibernation_ops->finish() before saving the image, so we should let
	 * the firmware know that we're going to enter the sleep state after all
	 */
	error = hibernation_ops->start();
	if (error)
		return error;

	suspend_console();
	error = device_suspend(PMSG_SUSPEND);
	if (error)
		goto Resume_console;

	error = hibernation_ops->prepare();
	if (error)
		goto Resume_devices;

	error = disable_nonboot_cpus();
	if (error)
		goto Finish;

	local_irq_disable();
	error = device_power_down(PMSG_SUSPEND);
	if (!error) {
		hibernation_ops->enter();
		/* We should never get here */
		while (1);
	}
	local_irq_enable();

	/*
	 * We don't need to reenable the nonboot CPUs or resume consoles, since
	 * the system is going to be halted anyway.
	 */
 Finish:
	hibernation_ops->finish();
 Resume_devices:
	device_resume();
 Resume_console:
	resume_console();
	return error;
}

/**
 *	power_down - Shut the machine down for hibernation.
 *
 *	Use the platform driver, if configured so; otherwise try
 *	to power off or reboot.
 */

static void power_down(void)
{
	switch (hibernation_mode) {
	case HIBERNATION_TEST:
	case HIBERNATION_TESTPROC:
		break;
	case HIBERNATION_REBOOT:
		kernel_restart(NULL);
		break;
	case HIBERNATION_PLATFORM:
		hibernation_platform_enter();
	case HIBERNATION_SHUTDOWN:
		kernel_power_off();
		break;
	}
	kernel_halt();
	/*
	 * Valid image is on the disk, if we continue we risk serious data
	 * corruption after resume.
	 */
	printk(KERN_CRIT "Please power me down manually\n");
	while(1);
}

static void unprepare_processes(void)
{
	thaw_processes();
	pm_restore_console();
}

static int prepare_processes(void)
{
	int error = 0;

	pm_prepare_console();
	if (freeze_processes()) {
		error = -EBUSY;
		unprepare_processes();
	}
	return error;