/* * ICP Wafer 5823 Single Board Computer WDT driver * http://www.icpamerica.com/wafer_5823.php * May also work on other similar models * * (c) Copyright 2002 Justin Cormack <justin@street-vision.com> * * Release 0.02 * * Based on advantechwdt.c which is based on wdt.c. * Original copyright messages: * * (c) Copyright 1996-1997 Alan Cox <alan@lxorguk.ukuu.org.uk>, * 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. * * 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> * */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include <linux/module.h> #include <linux/moduleparam.h> #include <linux/miscdevice.h> #include <linux/watchdog.h> #include <linux/fs.h> #include <linux/ioport.h> #include <linux/notifier.h> #include <linux/reboot.h> #include <linux/init.h> #include <linux/spinlock.h> #include <linux/io.h> #include <linux/uaccess.h> #define WATCHDOG_NAME "Wafer 5823 WDT" #define PFX WATCHDOG_NAME ": " #define WD_TIMO 60 /* 60 sec default timeout */ static unsigned long wafwdt_is_open; static char expect_close; static DEFINE_SPINLOCK(wafwdt_lock); /* * You must set these - there is no sane way to probe for this board. * * To enable, write the timeout value in seconds (1 to 255) to I/O * port WDT_START, then read the port to start the watchdog. To pat * the dog, read port WDT_STOP to stop the timer, then read WDT_START * to restart it again. */ static int wdt_stop = 0x843; static int wdt_start = 0x443; static int timeout = WD_TIMO; /* in seconds */ module_param(timeout, int, 0); MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. 1 <= timeout <= 255, default=" __MODULE_STRING(WD_TIMO) "."); static bool nowayout = WATCHDOG_NOWAYOUT; module_param(nowayout, bool, 0); MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); static void wafwdt_ping(void) { /* pat watchdog */ spin_lock(&wafwdt_lock); inb_p(wdt_stop); inb_p(wdt_start); spin_unlock(&wafwdt_lock); } static void wafwdt_start(void) { /* start up watchdog */ outb_p(timeout, wdt_start); inb_p(wdt_start); } static void wafwdt_stop(void) { /* stop watchdog */ inb_p(wdt_stop); } static ssize_t wafwdt_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) { /* See if we got the magic character 'V' and reload the timer */ if (count) { if (!nowayout) { size_t i; /* In case it was set long ago */ expect_close = 0; /* scan to see whether or not we got the magic character */ for (i = 0; i != count; i++) { char c; if (get_user(c, buf + i)) return -EFAULT; if (c == 'V') expect_close = 42; } } /* Well, anyhow someone wrote to us, we should return that favour */ wafwdt_ping(); } return count; } static long wafwdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { int new_timeout; void __user *argp = (void __user *)arg; int __user *p = argp; static const struct watchdog_info ident = { .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE, .firmware_version = 1, .identity = "Wafer 5823 WDT", }; switch (cmd) { case WDIOC_GETSUPPORT: if (copy_to_user(argp, &ident, sizeof(ident))) return -EFAULT; break; case WDIOC_GETSTATUS: case WDIOC_GETBOOTSTATUS: return put_user(0, p); case WDIOC_SETOPTIONS: { int options, retval = -EINVAL; if (get_user(options, p)) return -EFAULT; if (options & WDIOS_DISABLECARD) { wafwdt_stop(); retval = 0; } if (options & WDIOS_ENABLECARD) { wafwdt_start(); retval = 0; } return retval; } case WDIOC_KEEPALIVE: wafwdt_ping(); break; case WDIOC_SETTIMEOUT: if (get_user(new_timeout, p)) return -EFAULT; if ((new_timeout < 1) || (new_timeout > 255)) return -EINVAL; timeout = new_timeout; wafwdt_stop(); wafwdt_start(); /* Fall */ case WDIOC_GETTIMEOUT: return put_user(timeout, p); default: return -ENOTTY; } return 0; } static int wafwdt_open(struct inode *inode, struct file *file) { if (test_and_set_bit(0, &wafwdt_is_open)) return -EBUSY; /* * Activate */ wafwdt_start(); return nonseekable_open(inode, file); } static int wafwdt_close(struct inode *inode, struct file *file) { if (expect_close == 42) wafwdt_stop(); else { pr_crit("WDT device closed unexpectedly. WDT will not stop!\n"); wafwdt_ping(); } clear_bit(0, &wafwdt_is_open); expect_close = 0; return 0; } /* * Notifier for system down */ static int wafwdt_notify_sys(struct notifier_block *this, unsigned long code, void *unused) { if (code == SYS_DOWN || code == SYS_HALT) wafwdt_stop(); return NOTIFY_DONE; } /* * Kernel Interfaces */ static const struct file_operations wafwdt_fops = { .owner = THIS_MODULE, .llseek = no_llseek, .write = wafwdt_write, .unlocked_ioctl = wafwdt_ioctl, .open = wafwdt_open, .release = wafwdt_close, }; static struct miscdevice wafwdt_miscdev = { .minor = WATCHDOG_MINOR, .name = "watchdog", .fops = &wafwdt_fops, }; /* * The WDT needs to learn about soft shutdowns in order to * turn the timebomb registers off. */ static struct notifier_block wafwdt_notifier = { .notifier_call = wafwdt_notify_sys, }; static int __init wafwdt_init(void) { int ret; pr_info("WDT driver for Wafer 5823 single board computer initialising\n"); if (timeout < 1 || timeout > 255) { timeout = WD_TIMO; pr_info("timeout value must be 1 <= x <= 255, using %d\n", timeout); } if (wdt_stop != wdt_start) { if (!request_region(wdt_stop, 1, "Wafer 5823 WDT")) { pr_err("I/O address 0x%04x already in use\n", wdt_stop); ret = -EIO; goto error; } } if (!request_region(wdt_start, 1, "Wafer 5823 WDT")) { pr_err("I/O address 0x%04x already in use\n", wdt_start); ret = -EIO; goto error2; } ret = register_reboot_notifier(&wafwdt_notifier); if (ret != 0) { pr_err("cannot register reboot notifier (err=%d)\n", ret); goto error3; } ret = misc_register(&wafwdt_miscdev); if (ret != 0) { pr_err("cannot register miscdev on minor=%d (err=%d)\n", WATCHDOG_MINOR, ret); goto error4; } pr_info("initialized. timeout=%d sec (nowayout=%d)\n", timeout, nowayout); return ret; error4: unregister_reboot_notifier(&wafwdt_notifier); error3: release_region(wdt_start, 1); error2: if (wdt_stop != wdt_start) release_region(wdt_stop, 1); error: return ret; } static void __exit wafwdt_exit(void) { misc_deregister(&wafwdt_miscdev); unregister_reboot_notifier(&wafwdt_notifier); if (wdt_stop != wdt_start) release_region(wdt_stop, 1); release_region(wdt_start, 1); } module_init(wafwdt_init); module_exit(wafwdt_exit); MODULE_AUTHOR("Justin Cormack"); MODULE_DESCRIPTION("ICP Wafer 5823 Single Board Computer WDT driver"); MODULE_LICENSE("GPL"); /* end of wafer5823wdt.c */