| /* |
| * IndyDog 0.2 A Hardware Watchdog Device for SGI IP22 |
| * |
| * (c) Copyright 2002 Guido Guenther <agx@sigxcpu.org>, All Rights Reserved. |
| * |
| * 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. |
| * |
| * based on softdog.c by Alan Cox <alan@redhat.com> |
| */ |
| |
| #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/smp_lock.h> |
| #include <linux/init.h> |
| #include <asm/uaccess.h> |
| #include <asm/sgi/mc.h> |
| |
| static unsigned long indydog_alive; |
| static int expect_close = 0; |
| |
| #ifdef CONFIG_WATCHDOG_NOWAYOUT |
| static int nowayout = 1; |
| #else |
| static int nowayout = 0; |
| #endif |
| |
| MODULE_PARM(nowayout,"i"); |
| MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)"); |
| |
| static inline void indydog_ping(void) |
| { |
| sgimc->watchdogt = 0; |
| } |
| |
| /* |
| * Allow only one person to hold it open |
| */ |
| static int indydog_open(struct inode *inode, struct file *file) |
| { |
| u32 mc_ctrl0; |
| |
| if (test_and_set_bit(0,&indydog_alive)) |
| return -EBUSY; |
| |
| if (nowayout) { |
| MOD_INC_USE_COUNT; |
| } |
| |
| /* Activate timer */ |
| mc_ctrl0 = sgimc->cpuctrl0 | SGIMC_CCTRL0_WDOG; |
| sgimc->cpuctrl0 = mc_ctrl0; |
| indydog_ping(); |
| |
| indydog_alive = 1; |
| printk(KERN_INFO "Started watchdog timer.\n"); |
| |
| return 0; |
| } |
| |
| static int indydog_release(struct inode *inode, struct file *file) |
| { |
| /* Shut off the timer. |
| * Lock it in if it's a module and we set nowayout. */ |
| lock_kernel(); |
| if (expect_close) { |
| u32 mc_ctrl0 = sgimc->cpuctrl0; |
| mc_ctrl0 &= ~SGIMC_CCTRL0_WDOG; |
| sgimc->cpuctrl0 = mc_ctrl0; |
| printk(KERN_INFO "Stopped watchdog timer.\n"); |
| } else |
| printk(KERN_CRIT "WDT device closed unexpectedly. WDT will not stop!\n"); |
| clear_bit(0, &indydog_alive); |
| unlock_kernel(); |
| |
| return 0; |
| } |
| |
| static ssize_t indydog_write(struct file *file, const char *data, size_t len, loff_t *ppos) |
| { |
| /* Can't seek (pwrite) on this device */ |
| if (ppos != &file->f_pos) |
| return -ESPIPE; |
| |
| /* |
| * Refresh the timer. |
| */ |
| if (len) { |
| if (!nowayout) { |
| size_t i; |
| |
| /* In case it was set long ago */ |
| expect_close = 0; |
| |
| for (i = 0; i != len; i++) { |
| char c; |
| if (get_user(c, data + i)) |
| return -EFAULT; |
| if (c == 'V') |
| expect_close = 1; |
| } |
| } |
| indydog_ping(); |
| return 1; |
| } |
| return 0; |
| } |
| |
| static int indydog_ioctl(struct inode *inode, struct file *file, |
| unsigned int cmd, unsigned long arg) |
| { |
| static struct watchdog_info ident = { |
| options: WDIOF_MAGICCLOSE, |
| identity: "Hardware Watchdog for SGI IP22", |
| }; |
| switch (cmd) { |
| default: |
| return -ENOIOCTLCMD; |
| case WDIOC_GETSUPPORT: |
| if(copy_to_user((struct watchdog_info *)arg, &ident, sizeof(ident))) |
| return -EFAULT; |
| return 0; |
| case WDIOC_GETSTATUS: |
| case WDIOC_GETBOOTSTATUS: |
| return put_user(0,(int *)arg); |
| case WDIOC_KEEPALIVE: |
| indydog_ping(); |
| return 0; |
| } |
| } |
| |
| static struct file_operations indydog_fops = { |
| owner: THIS_MODULE, |
| write: indydog_write, |
| ioctl: indydog_ioctl, |
| open: indydog_open, |
| release: indydog_release, |
| }; |
| |
| static struct miscdevice indydog_miscdev = { |
| minor: WATCHDOG_MINOR, |
| name: "watchdog", |
| fops: &indydog_fops, |
| }; |
| |
| static const char banner[] __initdata = KERN_INFO "Hardware Watchdog Timer for SGI IP22: 0.2\n"; |
| |
| static int __init watchdog_init(void) |
| { |
| int ret = misc_register(&indydog_miscdev); |
| |
| if (ret) |
| return ret; |
| |
| printk(banner); |
| |
| return 0; |
| } |
| |
| static void __exit watchdog_exit(void) |
| { |
| misc_deregister(&indydog_miscdev); |
| } |
| |
| module_init(watchdog_init); |
| module_exit(watchdog_exit); |
| MODULE_LICENSE("GPL"); |