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32 results

disk.c

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  • disk.c 8.43 KiB
    /*
     * 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 <pavel@suse.cz>
     *
     * 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 "power.h"
    
    
    static int noresume = 0;
    char resume_file[256] = CONFIG_PM_STD_PARTITION;
    dev_t swsusp_resume_device;
    
    /**
     *	power_down - Shut machine down for hibernate.
     *	@mode:		Suspend-to-disk mode
     *
     *	Use the platform driver, if configured so, and return gracefully if it
     *	fails.
     *	Otherwise, try to power off and reboot. If they fail, halt the machine,
     *	there ain't no turning back.
     */
    
    static void power_down(suspend_disk_method_t mode)
    {
    	int error = 0;
    
    	switch(mode) {
    	case PM_DISK_PLATFORM:
    		kernel_shutdown_prepare(SYSTEM_SUSPEND_DISK);
    		error = pm_ops->enter(PM_SUSPEND_DISK);
    		break;
    	case PM_DISK_SHUTDOWN:
    		kernel_power_off();
    		break;
    	case PM_DISK_REBOOT:
    		kernel_restart(NULL);
    		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 inline void platform_finish(void)
    {
    	if (pm_disk_mode == PM_DISK_PLATFORM) {
    		if (pm_ops && pm_ops->finish)
    			pm_ops->finish(PM_SUSPEND_DISK);
    	}
    }
    
    static int prepare_processes(void)
    {
    	int error;
    
    	pm_prepare_console();
    
    	error = disable_nonboot_cpus();
    	if (error)
    		goto enable_cpus;
    
    	if (freeze_processes()) {
    		error = -EBUSY;
    		goto thaw;
    	}
    
    	/* Free memory before shutting down devices. */
    	if (!(error = swsusp_shrink_memory()))
    		return 0;
    thaw:
    	thaw_processes();
    enable_cpus:
    	enable_nonboot_cpus();
    	pm_restore_console();
    	return error;
    }
    
    static void unprepare_processes(void)
    {
    	platform_finish();
    	thaw_processes();
    	enable_nonboot_cpus();
    	pm_restore_console();
    }
    
    /**
     *	pm_suspend_disk - The granpappy of hibernation power management.
     *
     *	If we're going through the firmware, then get it over with quickly.
     *
     *	If not, then call swsusp to do its thing, then figure out how
     *	to power down the system.
     */
    
    int pm_suspend_disk(void)
    {
    	int error;
    
    	error = prepare_processes();
    	if (error)
    		return error;
    
    	suspend_console();
    	error = device_suspend(PMSG_FREEZE);
    	if (error) {
    		resume_console();
    		printk("Some devices failed to suspend\n");
    		unprepare_processes();
    		return error;
    	}
    
    	pr_debug("PM: snapshotting memory.\n");
    	in_suspend = 1;
    	if ((error = swsusp_suspend()))
    		goto Done;
    
    	if (in_suspend) {
    		device_resume();
    		resume_console();
    		pr_debug("PM: writing image.\n");
    		error = swsusp_write();
    		if (!error)
    			power_down(pm_disk_mode);
    		else {
    			swsusp_free();
    			unprepare_processes();
    			return error;
    		}
    	} else
    		pr_debug("PM: Image restored successfully.\n");
    
    	swsusp_free();
     Done:
    	device_resume();
    	resume_console();
    	unprepare_processes();
    	return error;
    }
    
    
    /**
     *	software_resume - Resume from a saved image.
     *
     *	Called as a late_initcall (so all devices are discovered and
     *	initialized), we call swsusp to see if we have a saved image or not.
     *	If so, we quiesce devices, the restore the saved image. We will
     *	return above (in pm_suspend_disk() ) if everything goes well.
     *	Otherwise, we fail gracefully and return to the normally
     *	scheduled program.
     *
     */
    
    static int software_resume(void)
    {
    	int error;
    
    	down(&pm_sem);
    	if (!swsusp_resume_device) {
    		if (!strlen(resume_file)) {
    			up(&pm_sem);
    			return -ENOENT;
    		}
    		swsusp_resume_device = name_to_dev_t(resume_file);
    		pr_debug("swsusp: Resume From Partition %s\n", resume_file);
    	} else {
    		pr_debug("swsusp: Resume From Partition %d:%d\n",
    			 MAJOR(swsusp_resume_device), MINOR(swsusp_resume_device));
    	}
    
    	if (noresume) {
    		/**
    		 * FIXME: If noresume is specified, we need to find the partition
    		 * and reset it back to normal swap space.
    		 */
    		up(&pm_sem);
    		return 0;
    	}
    
    	pr_debug("PM: Checking swsusp image.\n");
    
    	if ((error = swsusp_check()))
    		goto Done;
    
    	pr_debug("PM: Preparing processes for restore.\n");
    
    	if ((error = prepare_processes())) {
    		swsusp_close();
    		goto Done;
    	}
    
    	pr_debug("PM: Reading swsusp image.\n");
    
    	if ((error = swsusp_read())) {
    		swsusp_free();
    		goto Thaw;
    	}
    
    	pr_debug("PM: Preparing devices for restore.\n");
    
    	suspend_console();
    	if ((error = device_suspend(PMSG_PRETHAW))) {
    		resume_console();
    		printk("Some devices failed to suspend\n");
    		swsusp_free();
    		goto Thaw;
    	}
    
    	mb();
    
    	pr_debug("PM: Restoring saved image.\n");
    	swsusp_resume();
    	pr_debug("PM: Restore failed, recovering.n");
    	device_resume();
    	resume_console();
     Thaw:
    	unprepare_processes();
     Done:
    	/* For success case, the suspend path will release the lock */
    	up(&pm_sem);
    	pr_debug("PM: Resume from disk failed.\n");
    	return 0;
    }
    
    late_initcall(software_resume);
    
    
    static const char * const pm_disk_modes[] = {
    	[PM_DISK_FIRMWARE]	= "firmware",
    	[PM_DISK_PLATFORM]	= "platform",
    	[PM_DISK_SHUTDOWN]	= "shutdown",
    	[PM_DISK_REBOOT]	= "reboot",
    };
    
    /**
     *	disk - Control suspend-to-disk mode
     *
     *	Suspend-to-disk can be handled in several ways. The greatest
     *	distinction is who writes memory to disk - the firmware or the OS.
     *	If the firmware does it, we assume that it also handles suspending
     *	the system.
     *	If the OS does it, then we have three options for putting the system
     *	to sleep - using the platform driver (e.g. ACPI or other PM registers),
     *	powering off the system or rebooting the system (for testing).
     *
     *	The system will support either 'firmware' or 'platform', and that is
     *	known a priori (and encoded in pm_ops). But, the user may choose
     *	'shutdown' or 'reboot' as alternatives.
     *
     *	show() will display what the mode is currently set to.
     *	store() will accept one of
     *
     *	'firmware'
     *	'platform'
     *	'shutdown'
     *	'reboot'
     *
     *	It will only change to 'firmware' or 'platform' if the system
     *	supports it (as determined from pm_ops->pm_disk_mode).
     */
    
    static ssize_t disk_show(struct subsystem * subsys, char * buf)
    {
    	return sprintf(buf, "%s\n", pm_disk_modes[pm_disk_mode]);
    }
    
    
    static ssize_t disk_store(struct subsystem * s, const char * buf, size_t n)
    {
    	int error = 0;
    	int i;
    	int len;
    	char *p;
    	suspend_disk_method_t mode = 0;
    
    	p = memchr(buf, '\n', n);
    	len = p ? p - buf : n;
    
    	down(&pm_sem);
    	for (i = PM_DISK_FIRMWARE; i < PM_DISK_MAX; i++) {
    		if (!strncmp(buf, pm_disk_modes[i], len)) {
    			mode = i;
    			break;
    		}
    	}
    	if (mode) {
    		if (mode == PM_DISK_SHUTDOWN || mode == PM_DISK_REBOOT)
    			pm_disk_mode = mode;
    		else {
    			if (pm_ops && pm_ops->enter &&
    			    (mode == pm_ops->pm_disk_mode))
    				pm_disk_mode = mode;
    			else
    				error = -EINVAL;
    		}
    	} else
    		error = -EINVAL;
    
    	pr_debug("PM: suspend-to-disk mode set to '%s'\n",
    		 pm_disk_modes[mode]);
    	up(&pm_sem);
    	return error ? error : n;
    }
    
    power_attr(disk);
    
    static ssize_t resume_show(struct subsystem * subsys, char *buf)
    {
    	return sprintf(buf,"%d:%d\n", MAJOR(swsusp_resume_device),
    		       MINOR(swsusp_resume_device));
    }
    
    static ssize_t resume_store(struct subsystem *subsys, const char *buf, size_t n)
    {
    	unsigned int maj, min;
    	dev_t res;
    	int ret = -EINVAL;
    
    	if (sscanf(buf, "%u:%u", &maj, &min) != 2)
    		goto out;
    
    	res = MKDEV(maj,min);
    	if (maj != MAJOR(res) || min != MINOR(res))
    		goto out;
    
    	down(&pm_sem);
    	swsusp_resume_device = res;
    	up(&pm_sem);
    	printk("Attempting manual resume\n");
    	noresume = 0;
    	software_resume();
    	ret = n;
    out:
    	return ret;
    }
    
    power_attr(resume);
    
    static ssize_t image_size_show(struct subsystem * subsys, char *buf)
    {
    	return sprintf(buf, "%lu\n", image_size);
    }
    
    static ssize_t image_size_store(struct subsystem * subsys, const char * buf, size_t n)
    {
    	unsigned long size;
    
    	if (sscanf(buf, "%lu", &size) == 1) {
    		image_size = size;
    		return n;
    	}
    
    	return -EINVAL;
    }
    
    power_attr(image_size);
    
    static struct attribute * g[] = {
    	&disk_attr.attr,
    	&resume_attr.attr,
    	&image_size_attr.attr,
    	NULL,
    };
    
    
    static struct attribute_group attr_group = {
    	.attrs = g,
    };
    
    
    static int __init pm_disk_init(void)
    {
    	return sysfs_create_group(&power_subsys.kset.kobj,&attr_group);
    }
    
    core_initcall(pm_disk_init);
    
    
    static int __init resume_setup(char *str)
    {
    	if (noresume)
    		return 1;
    
    	strncpy( resume_file, str, 255 );
    	return 1;
    }
    
    static int __init noresume_setup(char *str)
    {
    	noresume = 1;
    	return 1;
    }
    
    __setup("noresume", noresume_setup);
    __setup("resume=", resume_setup);