diff options
Diffstat (limited to 'arch/um/drivers/harddog_kern.c')
| -rw-r--r-- | arch/um/drivers/harddog_kern.c | 178 |
1 files changed, 178 insertions, 0 deletions
diff --git a/arch/um/drivers/harddog_kern.c b/arch/um/drivers/harddog_kern.c new file mode 100644 index 000000000..6d381279b --- /dev/null +++ b/arch/um/drivers/harddog_kern.c @@ -0,0 +1,178 @@ +/* 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/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/mutex.h> +#include <linux/init.h> +#include <linux/spinlock.h> +#include <linux/uaccess.h> +#include "mconsole.h" + +MODULE_LICENSE("GPL"); + +static DEFINE_MUTEX(harddog_mutex); +static DEFINE_SPINLOCK(lock); +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 = -EBUSY; + char *sock = NULL; + + mutex_lock(&harddog_mutex); + spin_lock(&lock); + if(timer_alive) + goto err; +#ifdef CONFIG_WATCHDOG_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) + goto err; + + timer_alive = 1; + spin_unlock(&lock); + mutex_unlock(&harddog_mutex); + return nonseekable_open(inode, file); +err: + spin_unlock(&lock); + mutex_unlock(&harddog_mutex); + return err; +} + +extern void stop_watchdog(int in_fd, int out_fd); + +static int harddog_release(struct inode *inode, struct file *file) +{ + /* + * Shut off the timer. + */ + + spin_lock(&lock); + + stop_watchdog(harddog_in_fd, harddog_out_fd); + harddog_in_fd = -1; + harddog_out_fd = -1; + + timer_alive=0; + spin_unlock(&lock); + + return 0; +} + +extern int ping_watchdog(int fd); + +static ssize_t harddog_write(struct file *file, const char __user *data, size_t len, + loff_t *ppos) +{ + /* + * Refresh the timer. + */ + if(len) + return ping_watchdog(harddog_out_fd); + return 0; +} + +static int harddog_ioctl_unlocked(struct file *file, + unsigned int cmd, unsigned long arg) +{ + void __user *argp= (void __user *)arg; + static struct watchdog_info ident = { + WDIOC_SETTIMEOUT, + 0, + "UML Hardware Watchdog" + }; + switch (cmd) { + default: + return -ENOTTY; + case WDIOC_GETSUPPORT: + if(copy_to_user(argp, &ident, sizeof(ident))) + return -EFAULT; + return 0; + case WDIOC_GETSTATUS: + case WDIOC_GETBOOTSTATUS: + return put_user(0,(int __user *)argp); + case WDIOC_KEEPALIVE: + return ping_watchdog(harddog_out_fd); + } +} + +static long harddog_ioctl(struct file *file, + unsigned int cmd, unsigned long arg) +{ + long ret; + + mutex_lock(&harddog_mutex); + ret = harddog_ioctl_unlocked(file, cmd, arg); + mutex_unlock(&harddog_mutex); + + return ret; +} + +static const struct file_operations harddog_fops = { + .owner = THIS_MODULE, + .write = harddog_write, + .unlocked_ioctl = harddog_ioctl, + .open = harddog_open, + .release = harddog_release, + .llseek = no_llseek, +}; + +static struct miscdevice harddog_miscdev = { + .minor = WATCHDOG_MINOR, + .name = "watchdog", + .fops = &harddog_fops, +}; +module_misc_device(harddog_miscdev); |