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Diffstat (limited to 'arch/um/drivers/harddog_kern.c')
| -rw-r--r-- | arch/um/drivers/harddog_kern.c | 190 |
1 files changed, 190 insertions, 0 deletions
diff --git a/arch/um/drivers/harddog_kern.c b/arch/um/drivers/harddog_kern.c new file mode 100644 index 00000000000..147ec19f6bb --- /dev/null +++ b/arch/um/drivers/harddog_kern.c @@ -0,0 +1,190 @@ +/* UML hardware watchdog, shamelessly stolen from: + * + * SoftDog 0.05: A Software Watchdog Device + * + * (c) Copyright 1996 Alan Cox <alan@redhat.com>, All Rights Reserved. + * http://www.redhat.com + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + * + * Neither Alan Cox nor CymruNet Ltd. admit liability nor provide + * warranty for any of this software. This material is provided + * "AS-IS" and at no charge. + * + * (c) Copyright 1995 Alan Cox <alan@lxorguk.ukuu.org.uk> + * + * Software only watchdog driver. Unlike its big brother the WDT501P + * driver this won't always recover a failed machine. + * + * 03/96: Angelo Haritsis <ah@doc.ic.ac.uk> : + * Modularised. + * Added soft_margin; use upon insmod to change the timer delay. + * NB: uses same minor as wdt (WATCHDOG_MINOR); we could use separate + * minors. + * + * 19980911 Alan Cox + * Made SMP safe for 2.3.x + * + * 20011127 Joel Becker (jlbec@evilplan.org> + * Added soft_noboot; Allows testing the softdog trigger without + * requiring a recompile. + * Added WDIOC_GETTIMEOUT and WDIOC_SETTIMOUT. + */ + +#include <linux/module.h> +#include <linux/config.h> +#include <linux/types.h> +#include <linux/kernel.h> +#include <linux/fs.h> +#include <linux/mm.h> +#include <linux/miscdevice.h> +#include <linux/watchdog.h> +#include <linux/reboot.h> +#include <linux/smp_lock.h> +#include <linux/init.h> +#include <asm/uaccess.h> +#include "helper.h" +#include "mconsole.h" + +MODULE_LICENSE("GPL"); + +/* Locked by the BKL in harddog_open and harddog_release */ +static int timer_alive; +static int harddog_in_fd = -1; +static int harddog_out_fd = -1; + +/* + * Allow only one person to hold it open + */ + +extern int start_watchdog(int *in_fd_ret, int *out_fd_ret, char *sock); + +static int harddog_open(struct inode *inode, struct file *file) +{ + int err; + char *sock = NULL; + + lock_kernel(); + if(timer_alive) + return -EBUSY; +#ifdef CONFIG_HARDDOG_NOWAYOUT + __module_get(THIS_MODULE); +#endif + +#ifdef CONFIG_MCONSOLE + sock = mconsole_notify_socket(); +#endif + err = start_watchdog(&harddog_in_fd, &harddog_out_fd, sock); + if(err) return(err); + + timer_alive = 1; + unlock_kernel(); + return nonseekable_open(inode, file); +} + +extern void stop_watchdog(int in_fd, int out_fd); + +static int harddog_release(struct inode *inode, struct file *file) +{ + /* + * Shut off the timer. + */ + lock_kernel(); + + stop_watchdog(harddog_in_fd, harddog_out_fd); + harddog_in_fd = -1; + harddog_out_fd = -1; + + timer_alive=0; + unlock_kernel(); + return 0; +} + +extern int ping_watchdog(int fd); + +static ssize_t harddog_write(struct file *file, const char *data, size_t len, + loff_t *ppos) +{ + /* + * Refresh the timer. + */ + if(len) + return(ping_watchdog(harddog_out_fd)); + return 0; +} + +static int harddog_ioctl(struct inode *inode, struct file *file, + unsigned int cmd, unsigned long arg) +{ + static struct watchdog_info ident = { + WDIOC_SETTIMEOUT, + 0, + "UML Hardware Watchdog" + }; + switch (cmd) { + default: + return -ENOTTY; + case WDIOC_GETSUPPORT: + if(copy_to_user((struct harddog_info *)arg, &ident, + sizeof(ident))) + return -EFAULT; + return 0; + case WDIOC_GETSTATUS: + case WDIOC_GETBOOTSTATUS: + return put_user(0,(int *)arg); + case WDIOC_KEEPALIVE: + return(ping_watchdog(harddog_out_fd)); + } +} + +static struct file_operations harddog_fops = { + .owner = THIS_MODULE, + .write = harddog_write, + .ioctl = harddog_ioctl, + .open = harddog_open, + .release = harddog_release, +}; + +static struct miscdevice harddog_miscdev = { + .minor = WATCHDOG_MINOR, + .name = "watchdog", + .fops = &harddog_fops, +}; + +static char banner[] __initdata = KERN_INFO "UML Watchdog Timer\n"; + +static int __init harddog_init(void) +{ + int ret; + + ret = misc_register(&harddog_miscdev); + + if (ret) + return ret; + + printk(banner); + + return(0); +} + +static void __exit harddog_exit(void) +{ + misc_deregister(&harddog_miscdev); +} + +module_init(harddog_init); +module_exit(harddog_exit); + +/* + * Overrides for Emacs so that we follow Linus's tabbing style. + * Emacs will notice this stuff at the end of the file and automatically + * adjust the settings for this buffer only. This must remain at the end + * of the file. + * --------------------------------------------------------------------------- + * Local variables: + * c-file-style: "linux" + * End: + */ |