/* * IB700 Single Board Computer WDT driver * * (c) Copyright 2001 Charles Howes * * Based on advantechwdt.c which is based on acquirewdt.c which * is based on wdt.c. * * (c) Copyright 2000-2001 Marek Michalkiewicz * * Based on acquirewdt.c which is based on wdt.c. * Original copyright messages: * * (c) Copyright 1996 Alan Cox , 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 * * 14-Dec-2001 Matt Domsch * Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT * Added timeout module option to override default * */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include static unsigned long ibwdt_is_open; static spinlock_t ibwdt_lock; static char expect_close; #define PFX "ib700wdt: " /* * * Watchdog Timer Configuration * * The function of the watchdog timer is to reset the system * automatically and is defined at I/O port 0443H. To enable the * watchdog timer and allow the system to reset, write I/O port 0443H. * To disable the timer, write I/O port 0441H for the system to stop the * watchdog function. The timer has a tolerance of 20% for its * intervals. * * The following describes how the timer should be programmed. * * Enabling Watchdog: * MOV AX,000FH (Choose the values from 0 to F) * MOV DX,0443H * OUT DX,AX * * Disabling Watchdog: * MOV AX,000FH (Any value is fine.) * MOV DX,0441H * OUT DX,AX * * Watchdog timer control table: * Level Value Time/sec | Level Value Time/sec * 1 F 0 | 9 7 16 * 2 E 2 | 10 6 18 * 3 D 4 | 11 5 20 * 4 C 6 | 12 4 22 * 5 B 8 | 13 3 24 * 6 A 10 | 14 2 26 * 7 9 12 | 15 1 28 * 8 8 14 | 16 0 30 * */ static int wd_times[] = { 30, /* 0x0 */ 28, /* 0x1 */ 26, /* 0x2 */ 24, /* 0x3 */ 22, /* 0x4 */ 20, /* 0x5 */ 18, /* 0x6 */ 16, /* 0x7 */ 14, /* 0x8 */ 12, /* 0x9 */ 10, /* 0xA */ 8, /* 0xB */ 6, /* 0xC */ 4, /* 0xD */ 2, /* 0xE */ 0, /* 0xF */ }; #define WDT_STOP 0x441 #define WDT_START 0x443 /* Default timeout */ #define WD_TIMO 0 /* 30 seconds +/- 20%, from table */ static int wd_margin = WD_TIMO; static int nowayout = WATCHDOG_NOWAYOUT; module_param(nowayout, int, 0); MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)"); /* * Kernel methods. */ static void ibwdt_ping(void) { /* Write a watchdog value */ outb_p(wd_margin, WDT_START); } static ssize_t ibwdt_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) { if (count) { if (!nowayout) { size_t i; /* In case it was set long ago */ expect_close = 0; for (i = 0; i != count; i++) { char c; if (get_user(c, buf + i)) return -EFAULT; if (c == 'V') expect_close = 42; } } ibwdt_ping(); } return count; } static int ibwdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg) { int i, new_margin; void __user *argp = (void __user *)arg; int __user *p = argp; static struct watchdog_info ident = { .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE, .firmware_version = 1, .identity = "IB700 WDT", }; switch (cmd) { case WDIOC_GETSUPPORT: if (copy_to_user(argp, &ident, sizeof(ident))) return -EFAULT; break; case WDIOC_GETSTATUS: return put_user(0, p); case WDIOC_KEEPALIVE: ibwdt_ping(); break; case WDIOC_SETTIMEOUT: if (get_user(new_margin, p)) return -EFAULT; if ((new_margin < 0) || (new_margin > 30)) return -EINVAL; for (i = 0x0F; i > -1; i--) if (wd_times[i] > new_margin) break; wd_margin = i; ibwdt_ping(); /* Fall */ case WDIOC_GETTIMEOUT: return put_user(wd_times[wd_margin], p); break; default: return -ENOIOCTLCMD; } return 0; } static int ibwdt_open(struct inode *inode, struct file *file) { spin_lock(&ibwdt_lock); if (test_and_set_bit(0, &ibwdt_is_open)) { spin_unlock(&ibwdt_lock); return -EBUSY; } if (nowayout) __module_get(THIS_MODULE); /* Activate */ ibwdt_ping(); spin_unlock(&ibwdt_lock); return nonseekable_open(inode, file); } static int ibwdt_close(struct inode *inode, struct file *file) { spin_lock(&ibwdt_lock); if (expect_close == 42) outb_p(0, WDT_STOP); else printk(KERN_CRIT PFX "WDT device closed unexpectedly. WDT will not stop!\n"); clear_bit(0, &ibwdt_is_open); expect_close = 0; spin_unlock(&ibwdt_lock); return 0; } /* * Notifier for system down */ static int ibwdt_notify_sys(struct notifier_block *this, unsigned long code, void *unused) { if (code == SYS_DOWN || code == SYS_HALT) { /* Turn the WDT off */ outb_p(0, WDT_STOP); } return NOTIFY_DONE; } /* * Kernel Interfaces */ static struct file_operations ibwdt_fops = { .owner = THIS_MODULE, .llseek = no_llseek, .write = ibwdt_write, .ioctl = ibwdt_ioctl, .open = ibwdt_open, .release = ibwdt_close, }; static struct miscdevice ibwdt_miscdev = { .minor = WATCHDOG_MINOR, .name = "watchdog", .fops = &ibwdt_fops, }; /* * The WDT needs to learn about soft shutdowns in order to * turn the timebomb registers off. */ static struct notifier_block ibwdt_notifier = { .notifier_call = ibwdt_notify_sys, }; static int __init ibwdt_init(void) { int res; printk(KERN_INFO PFX "WDT driver for IB700 single board computer initialising.\n"); spin_lock_init(&ibwdt_lock); res = misc_register(&ibwdt_miscdev); if (res) { printk (KERN_ERR PFX "failed to register misc device\n"); goto out_nomisc; } #if WDT_START != WDT_STOP if (!request_region(WDT_STOP, 1, "IB700 WDT")) { printk (KERN_ERR PFX "STOP method I/O %X is not available.\n", WDT_STOP); res = -EIO; goto out_nostopreg; } #endif if (!request_region(WDT_START, 1, "IB700 WDT")) { printk (KERN_ERR PFX "START method I/O %X is not available.\n", WDT_START); res = -EIO; goto out_nostartreg; } res = register_reboot_notifier(&ibwdt_notifier); if (res) { printk (KERN_ERR PFX "Failed to register reboot notifier.\n"); goto out_noreboot; } return 0; out_noreboot: release_region(WDT_START, 1); out_nostartreg: #if WDT_START != WDT_STOP release_region(WDT_STOP, 1); #endif out_nostopreg: misc_deregister(&ibwdt_miscdev); out_nomisc: return res; } static void __exit ibwdt_exit(void) { misc_deregister(&ibwdt_miscdev); unregister_reboot_notifier(&ibwdt_notifier); #if WDT_START != WDT_STOP release_region(WDT_STOP,1); #endif release_region(WDT_START,1); } module_init(ibwdt_init); module_exit(ibwdt_exit); MODULE_AUTHOR("Charles Howes "); MODULE_DESCRIPTION("IB700 SBC watchdog driver"); MODULE_LICENSE("GPL"); MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); /* end of ib700wdt.c */