/* * IndyDog 0.3 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/moduleparam.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/notifier.h> #include <linux/reboot.h> #include <linux/init.h> #include <linux/uaccess.h> #include <asm/sgi/mc.h> #define PFX "indydog: " static unsigned long indydog_alive; static spinlock_t indydog_lock; #define WATCHDOG_TIMEOUT 30 /* 30 sec default timeout */ static int nowayout = WATCHDOG_NOWAYOUT; module_param(nowayout, int, 0); MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); static void indydog_start(void) { u32 mc_ctrl0; spin_lock(&indydog_lock); mc_ctrl0 = sgimc->cpuctrl0; mc_ctrl0 = sgimc->cpuctrl0 | SGIMC_CCTRL0_WDOG; sgimc->cpuctrl0 = mc_ctrl0; spin_unlock(&indydog_lock); } static void indydog_stop(void) { u32 mc_ctrl0; spin_lock(&indydog_lock); mc_ctrl0 = sgimc->cpuctrl0; mc_ctrl0 &= ~SGIMC_CCTRL0_WDOG; sgimc->cpuctrl0 = mc_ctrl0; spin_unlock(&indydog_lock); printk(KERN_INFO PFX "Stopped watchdog timer.\n"); } static 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) { if (test_and_set_bit(0, &indydog_alive)) return -EBUSY; if (nowayout) __module_get(THIS_MODULE); /* Activate timer */ indydog_start(); indydog_ping(); indydog_alive = 1; printk(KERN_INFO "Started watchdog timer.\n"); return nonseekable_open(inode, file); } static int indydog_release(struct inode *inode, struct file *file) { /* Shut off the timer. * Lock it in if it's a module and we defined ...NOWAYOUT */ if (!nowayout) indydog_stop(); /* Turn the WDT off */ clear_bit(0, &indydog_alive); return 0; } static ssize_t indydog_write(struct file *file, const char *data, size_t len, loff_t *ppos) { /* Refresh the timer. */ if (len) indydog_ping(); return len; } static long indydog_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { int options, retval = -EINVAL; static struct watchdog_info ident = { .options = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, .firmware_version = 0, .identity = "Hardware Watchdog for SGI IP22", }; switch (cmd) { 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_SETOPTIONS: { if (get_user(options, (int *)arg)) return -EFAULT; if (options & WDIOS_DISABLECARD) { indydog_stop(); retval = 0; } if (options & WDIOS_ENABLECARD) { indydog_start(); retval = 0; } return retval; } case WDIOC_KEEPALIVE: indydog_ping(); return 0; case WDIOC_GETTIMEOUT: return put_user(WATCHDOG_TIMEOUT, (int *)arg); default: return -ENOTTY; } } static int indydog_notify_sys(struct notifier_block *this, unsigned long code, void *unused) { if (code == SYS_DOWN || code == SYS_HALT) indydog_stop(); /* Turn the WDT off */ return NOTIFY_DONE; } static const struct file_operations indydog_fops = { .owner = THIS_MODULE, .llseek = no_llseek, .write = indydog_write, .unlocked_ioctl = indydog_ioctl, .open = indydog_open, .release = indydog_release, }; static struct miscdevice indydog_miscdev = { .minor = WATCHDOG_MINOR, .name = "watchdog", .fops = &indydog_fops, }; static struct notifier_block indydog_notifier = { .notifier_call = indydog_notify_sys, }; static char banner[] __initdata = KERN_INFO PFX "Hardware Watchdog Timer for SGI IP22: 0.3\n"; static int __init watchdog_init(void) { int ret; spin_lock_init(&indydog_lock); ret = register_reboot_notifier(&indydog_notifier); if (ret) { printk(KERN_ERR PFX "cannot register reboot notifier (err=%d)\n", ret); return ret; } ret = misc_register(&indydog_miscdev); if (ret) { printk(KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n", WATCHDOG_MINOR, ret); unregister_reboot_notifier(&indydog_notifier); return ret; } printk(banner); return 0; } static void __exit watchdog_exit(void) { misc_deregister(&indydog_miscdev); unregister_reboot_notifier(&indydog_notifier); } module_init(watchdog_init); module_exit(watchdog_exit); MODULE_AUTHOR("Guido Guenther <agx@sigxcpu.org>"); MODULE_DESCRIPTION("Hardware Watchdog Device for SGI IP22"); MODULE_LICENSE("GPL"); MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);