/* * 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 "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();	disable_nonboot_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_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 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; 	error = device_suspend(PMSG_FREEZE);	if (error) {		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();		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();	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"); 	if ((error = device_suspend(PMSG_FREEZE))) {		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(); 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 char * 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);