![Pavel Machek](/assets/img/avatar_default.png)
Cleanup write-only variable, suggested by D Binderman. Signed-off-by: Pavel Machek <pavel@suse.cz> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
470 lines
9.6 KiB
C
470 lines
9.6 KiB
C
/*
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* kernel/power/disk.c - Suspend-to-disk support.
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*
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* Copyright (c) 2003 Patrick Mochel
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* Copyright (c) 2003 Open Source Development Lab
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* Copyright (c) 2004 Pavel Machek <pavel@suse.cz>
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*
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* This file is released under the GPLv2.
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*
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*/
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#include <linux/suspend.h>
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#include <linux/syscalls.h>
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#include <linux/reboot.h>
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#include <linux/string.h>
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#include <linux/device.h>
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#include <linux/delay.h>
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#include <linux/fs.h>
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#include <linux/mount.h>
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#include <linux/pm.h>
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#include <linux/console.h>
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#include <linux/cpu.h>
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#include <linux/freezer.h>
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#include "power.h"
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static int noresume = 0;
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char resume_file[256] = CONFIG_PM_STD_PARTITION;
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dev_t swsusp_resume_device;
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sector_t swsusp_resume_block;
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/**
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* platform_prepare - prepare the machine for hibernation using the
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* platform driver if so configured and return an error code if it fails
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*/
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static inline int platform_prepare(void)
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{
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int error = 0;
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if (pm_disk_mode == PM_DISK_PLATFORM) {
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if (pm_ops && pm_ops->prepare)
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error = pm_ops->prepare(PM_SUSPEND_DISK);
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}
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return error;
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}
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/**
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* power_down - Shut machine down for hibernate.
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* @mode: Suspend-to-disk mode
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*
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* Use the platform driver, if configured so, and return gracefully if it
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* fails.
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* Otherwise, try to power off and reboot. If they fail, halt the machine,
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* there ain't no turning back.
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*/
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static void power_down(suspend_disk_method_t mode)
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{
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switch(mode) {
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case PM_DISK_PLATFORM:
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kernel_shutdown_prepare(SYSTEM_SUSPEND_DISK);
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pm_ops->enter(PM_SUSPEND_DISK);
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break;
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case PM_DISK_SHUTDOWN:
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kernel_power_off();
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break;
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case PM_DISK_REBOOT:
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kernel_restart(NULL);
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break;
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}
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kernel_halt();
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/* Valid image is on the disk, if we continue we risk serious data corruption
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after resume. */
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printk(KERN_CRIT "Please power me down manually\n");
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while(1);
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}
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static inline void platform_finish(void)
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{
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if (pm_disk_mode == PM_DISK_PLATFORM) {
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if (pm_ops && pm_ops->finish)
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pm_ops->finish(PM_SUSPEND_DISK);
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}
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}
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static int prepare_processes(void)
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{
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int error = 0;
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pm_prepare_console();
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error = disable_nonboot_cpus();
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if (error)
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goto enable_cpus;
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if (freeze_processes()) {
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error = -EBUSY;
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goto thaw;
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}
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if (pm_disk_mode == PM_DISK_TESTPROC) {
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printk("swsusp debug: Waiting for 5 seconds.\n");
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mdelay(5000);
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goto thaw;
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}
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error = platform_prepare();
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if (error)
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goto thaw;
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/* Free memory before shutting down devices. */
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if (!(error = swsusp_shrink_memory()))
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return 0;
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platform_finish();
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thaw:
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thaw_processes();
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enable_cpus:
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enable_nonboot_cpus();
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pm_restore_console();
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return error;
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}
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static void unprepare_processes(void)
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{
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platform_finish();
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thaw_processes();
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enable_nonboot_cpus();
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pm_restore_console();
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}
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/**
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* pm_suspend_disk - The granpappy of hibernation power management.
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*
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* If we're going through the firmware, then get it over with quickly.
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*
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* If not, then call swsusp to do its thing, then figure out how
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* to power down the system.
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*/
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int pm_suspend_disk(void)
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{
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int error;
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error = prepare_processes();
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if (error)
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return error;
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if (pm_disk_mode == PM_DISK_TESTPROC)
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return 0;
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suspend_console();
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error = device_suspend(PMSG_FREEZE);
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if (error) {
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resume_console();
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printk("Some devices failed to suspend\n");
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goto Thaw;
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}
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if (pm_disk_mode == PM_DISK_TEST) {
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printk("swsusp debug: Waiting for 5 seconds.\n");
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mdelay(5000);
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goto Done;
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}
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pr_debug("PM: snapshotting memory.\n");
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in_suspend = 1;
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if ((error = swsusp_suspend()))
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goto Done;
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if (in_suspend) {
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device_resume();
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resume_console();
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pr_debug("PM: writing image.\n");
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error = swsusp_write();
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if (!error)
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power_down(pm_disk_mode);
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else {
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swsusp_free();
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goto Thaw;
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}
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} else {
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pr_debug("PM: Image restored successfully.\n");
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}
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swsusp_free();
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Done:
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device_resume();
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resume_console();
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Thaw:
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unprepare_processes();
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return error;
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}
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/**
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* software_resume - Resume from a saved image.
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*
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* Called as a late_initcall (so all devices are discovered and
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* initialized), we call swsusp to see if we have a saved image or not.
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* If so, we quiesce devices, the restore the saved image. We will
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* return above (in pm_suspend_disk() ) if everything goes well.
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* Otherwise, we fail gracefully and return to the normally
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* scheduled program.
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*
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*/
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static int software_resume(void)
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{
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int error;
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mutex_lock(&pm_mutex);
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if (!swsusp_resume_device) {
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if (!strlen(resume_file)) {
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mutex_unlock(&pm_mutex);
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return -ENOENT;
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}
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swsusp_resume_device = name_to_dev_t(resume_file);
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pr_debug("swsusp: Resume From Partition %s\n", resume_file);
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} else {
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pr_debug("swsusp: Resume From Partition %d:%d\n",
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MAJOR(swsusp_resume_device), MINOR(swsusp_resume_device));
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}
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if (noresume) {
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/**
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* FIXME: If noresume is specified, we need to find the partition
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* and reset it back to normal swap space.
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*/
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mutex_unlock(&pm_mutex);
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return 0;
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}
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pr_debug("PM: Checking swsusp image.\n");
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if ((error = swsusp_check()))
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goto Done;
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pr_debug("PM: Preparing processes for restore.\n");
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if ((error = prepare_processes())) {
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swsusp_close();
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goto Done;
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}
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pr_debug("PM: Reading swsusp image.\n");
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if ((error = swsusp_read())) {
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swsusp_free();
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goto Thaw;
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}
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pr_debug("PM: Preparing devices for restore.\n");
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suspend_console();
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if ((error = device_suspend(PMSG_PRETHAW))) {
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resume_console();
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printk("Some devices failed to suspend\n");
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swsusp_free();
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goto Thaw;
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}
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mb();
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pr_debug("PM: Restoring saved image.\n");
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swsusp_resume();
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pr_debug("PM: Restore failed, recovering.n");
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device_resume();
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resume_console();
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Thaw:
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unprepare_processes();
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Done:
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/* For success case, the suspend path will release the lock */
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mutex_unlock(&pm_mutex);
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pr_debug("PM: Resume from disk failed.\n");
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return 0;
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}
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late_initcall(software_resume);
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static const char * const pm_disk_modes[] = {
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[PM_DISK_FIRMWARE] = "firmware",
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[PM_DISK_PLATFORM] = "platform",
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[PM_DISK_SHUTDOWN] = "shutdown",
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[PM_DISK_REBOOT] = "reboot",
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[PM_DISK_TEST] = "test",
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[PM_DISK_TESTPROC] = "testproc",
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};
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/**
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* disk - Control suspend-to-disk mode
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*
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* Suspend-to-disk can be handled in several ways. The greatest
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* distinction is who writes memory to disk - the firmware or the OS.
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* If the firmware does it, we assume that it also handles suspending
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* the system.
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* If the OS does it, then we have three options for putting the system
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* to sleep - using the platform driver (e.g. ACPI or other PM registers),
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* powering off the system or rebooting the system (for testing).
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*
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* The system will support either 'firmware' or 'platform', and that is
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* known a priori (and encoded in pm_ops). But, the user may choose
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* 'shutdown' or 'reboot' as alternatives.
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*
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* show() will display what the mode is currently set to.
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* store() will accept one of
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*
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* 'firmware'
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* 'platform'
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* 'shutdown'
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* 'reboot'
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*
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* It will only change to 'firmware' or 'platform' if the system
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* supports it (as determined from pm_ops->pm_disk_mode).
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*/
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static ssize_t disk_show(struct subsystem * subsys, char * buf)
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{
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return sprintf(buf, "%s\n", pm_disk_modes[pm_disk_mode]);
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}
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static ssize_t disk_store(struct subsystem * s, const char * buf, size_t n)
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{
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int error = 0;
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int i;
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int len;
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char *p;
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suspend_disk_method_t mode = 0;
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p = memchr(buf, '\n', n);
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len = p ? p - buf : n;
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mutex_lock(&pm_mutex);
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for (i = PM_DISK_FIRMWARE; i < PM_DISK_MAX; i++) {
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if (!strncmp(buf, pm_disk_modes[i], len)) {
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mode = i;
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break;
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}
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}
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if (mode) {
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if (mode == PM_DISK_SHUTDOWN || mode == PM_DISK_REBOOT ||
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mode == PM_DISK_TEST || mode == PM_DISK_TESTPROC) {
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pm_disk_mode = mode;
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} else {
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if (pm_ops && pm_ops->enter &&
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(mode == pm_ops->pm_disk_mode))
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pm_disk_mode = mode;
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else
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error = -EINVAL;
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}
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} else {
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error = -EINVAL;
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}
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pr_debug("PM: suspend-to-disk mode set to '%s'\n",
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pm_disk_modes[mode]);
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mutex_unlock(&pm_mutex);
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return error ? error : n;
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}
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power_attr(disk);
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static ssize_t resume_show(struct subsystem * subsys, char *buf)
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{
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return sprintf(buf,"%d:%d\n", MAJOR(swsusp_resume_device),
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MINOR(swsusp_resume_device));
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}
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static ssize_t resume_store(struct subsystem *subsys, const char *buf, size_t n)
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{
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unsigned int maj, min;
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dev_t res;
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int ret = -EINVAL;
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if (sscanf(buf, "%u:%u", &maj, &min) != 2)
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goto out;
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res = MKDEV(maj,min);
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if (maj != MAJOR(res) || min != MINOR(res))
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goto out;
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mutex_lock(&pm_mutex);
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swsusp_resume_device = res;
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mutex_unlock(&pm_mutex);
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printk("Attempting manual resume\n");
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noresume = 0;
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software_resume();
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ret = n;
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out:
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return ret;
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}
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power_attr(resume);
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static ssize_t image_size_show(struct subsystem * subsys, char *buf)
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{
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return sprintf(buf, "%lu\n", image_size);
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}
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static ssize_t image_size_store(struct subsystem * subsys, const char * buf, size_t n)
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{
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unsigned long size;
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if (sscanf(buf, "%lu", &size) == 1) {
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image_size = size;
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return n;
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}
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return -EINVAL;
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}
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power_attr(image_size);
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static struct attribute * g[] = {
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&disk_attr.attr,
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&resume_attr.attr,
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&image_size_attr.attr,
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NULL,
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};
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static struct attribute_group attr_group = {
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.attrs = g,
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};
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static int __init pm_disk_init(void)
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{
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return sysfs_create_group(&power_subsys.kset.kobj,&attr_group);
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}
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core_initcall(pm_disk_init);
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static int __init resume_setup(char *str)
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{
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if (noresume)
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return 1;
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strncpy( resume_file, str, 255 );
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return 1;
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}
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static int __init resume_offset_setup(char *str)
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{
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unsigned long long offset;
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if (noresume)
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return 1;
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if (sscanf(str, "%llu", &offset) == 1)
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swsusp_resume_block = offset;
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return 1;
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}
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static int __init noresume_setup(char *str)
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{
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noresume = 1;
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return 1;
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}
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__setup("noresume", noresume_setup);
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__setup("resume_offset=", resume_offset_setup);
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__setup("resume=", resume_setup);
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