disk.c

Kernel code of linux kernel

/*
 * 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 <linux/ftrace.h>

#include "power.h"


static int noresume = 0;
static 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->begin && ops->end &&  ops->pre_snapshot
	    && ops->prepare && ops->finish && 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);
}

#ifdef CONFIG_PM_DEBUG
static void hibernation_debug_sleep(void)
{
	printk(KERN_INFO "hibernation debug: Waiting for 5 seconds.\n");
	mdelay(5000);
}

static int hibernation_testmode(int mode)
{
	if (hibernation_mode == mode) {
		hibernation_debug_sleep();
		return 1;
	}
	return 0;
}

static int hibernation_test(int level)
{
	if (pm_test_level == level) {
		hibernation_debug_sleep();
		return 1;
	}
	return 0;
}
#else /* !CONFIG_PM_DEBUG */
static int hibernation_testmode(int mode) { return 0; }
static int hibernation_test(int level) { return 0; }
#endif /* !CONFIG_PM_DEBUG */

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

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

/**
 *	platform_end - tell the platform driver that we've entered the
 *	working state
 */

static void platform_end(int platform_mode)
{
	if (platform_mode && hibernation_ops)
		hibernation_ops->end();
}

/**
 *	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();
}

/**
 *	platform_recover - recover the platform from a failure to suspend
 *	devices.
 */

static void platform_recover(int platform_mode)
{
	if (platform_mode && hibernation_ops && hibernation_ops->recover)
		hibernation_ops->recover();
}

/**
 *	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.
 */

static int create_image(int platform_mode)
{
	int error;

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

	device_pm_lock();
	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 "PM: Some devices failed to power down, "
			"aborting hibernation\n");
		goto Enable_irqs;
	}

	if (hibernation_test(TEST_CORE))
		goto Power_up;

	in_suspend = 1;
	save_processor_state();
	error = swsusp_arch_suspend();
	if (error)
		printk(KERN_ERR "PM: Error %d creating hibernation image\n",
			error);
	/* Restore control flow magically appears here */
	restore_processor_state();
	if (!in_suspend)
		platform_leave(platform_mode);
 Power_up:
	/* NOTE:  device_power_up() is just a resume() for devices
	 * that suspended with irqs off ... no overall powerup.
	 */
	device_power_up(in_suspend ?
		(error ? PMSG_RECOVER : PMSG_THAW) : PMSG_RESTORE);
 Enable_irqs:
	local_irq_enable();
	device_pm_unlock();
	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, ftrace_save;

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

	error = platform_begin(platform_mode);
	if (error)
		goto Close;

	suspend_console();
	ftrace_save = __ftrace_enabled_save();
	error = device_suspend(PMSG_FREEZE);
	if (error)
		goto Recover_platform;

	if (hibernation_test(TEST_DEVICES))
		goto Recover_platform;

	error = platform_pre_snapshot(platform_mode);
	if (error || hibernation_test(TEST_PLATFORM))
		goto Finish;

	error = disable_nonboot_cpus();
	if (!error) {
		if (hibernation_test(TEST_CPUS))
			goto Enable_cpus;

		if (hibernation_testmode(HIBERNATION_TEST))
			goto Enable_cpus;

		error = create_image(platform_mode);
		/* Control returns here after successful restore */
	}
 Enable_cpus:
	enable_nonboot_cpus();
 Finish:
	platform_finish(platform_mode);
 Resume_devices:
	device_resume(in_suspend ?
		(error ? PMSG_RECOVER : PMSG_THAW) : PMSG_RESTORE);
	__ftrace_enabled_restore(ftrace_save);
	resume_console();
 Close:
	platform_end(platform_mode);
	return error;

 Recover_platform:
	platform_recover(platform_mode);
	goto Resume_devices;
}

/**
 *	resume_target_kernel - prepare devices that need to be suspended with
 *	interrupts off, restore the contents of highmem that have not been
 *	restored yet from the image and run the low level code that will restore
 *	the remaining contents of memory and switch to the just restored target
 *	kernel.
 */

static int resume_target_kernel(void)
{
	int error;

	device_pm_lock();
	local_irq_disable();
	error = device_power_down(PMSG_QUIESCE);
	if (error) {
		printk(KERN_ERR "PM: Some devices failed to power down, "
			"aborting resume\n");
		goto Enable_irqs;
	}
	/* We'll ignore saved state, but this gets preempt count (etc) right */
	save_processor_state();
	error = restore_highmem();
	if (!error) {
		error = swsusp_arch_resume();
		/*
		 * The code below is only ever reached in case of a failure.
		 * Otherwise execution continues at place where
		 * swsusp_arch_suspend() was called
		 */
		BUG_ON(!error);
		/* This call to restore_highmem() undos the previous one */
		restore_highmem();
	}
	/*
	 * The only reason why swsusp_arch_resume() can fail is memory being
	 * very tight, so we have to free it as soon as we can to avoid
	 * subsequent failures
	 */
	swsusp_free();
	restore_processor_state();
	touch_softlockup_watchdog();
	device_power_up(PMSG_RECOVER);
 Enable_irqs:
	local_irq_enable();
	device_pm_unlock();
	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, ftrace_save;

	pm_prepare_console();
	suspend_console();
	ftrace_save = __ftrace_enabled_save();
	error = device_suspend(PMSG_QUIESCE);
	if (error)
		goto Finish;

	error = platform_pre_restore(platform_mode);
	if (!error) {
		error = disable_nonboot_cpus();
		if (!error)
			error = resume_target_kernel();
		enable_nonboot_cpus();
	}
	platform_restore_cleanup(platform_mode);
	device_resume(PMSG_RECOVER);
 Finish:
	__ftrace_enabled_restore(ftrace_save);
	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, ftrace_save;

	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->begin();
	if (error)
		goto Close;

	suspend_console();
	ftrace_save = __ftrace_enabled_save();
	error = device_suspend(PMSG_HIBERNATE);
	if (error) {
		if (hibernation_ops->recover)
			hibernation_ops->recover();
		goto Resume_devices;
	}

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

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

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

	/*