334 lines
7.2 KiB
C
334 lines
7.2 KiB
C
/*
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* ICP Wafer 5823 Single Board Computer WDT driver
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* http://www.icpamerica.com/wafer_5823.php
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* May also work on other similar models
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*
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* (c) Copyright 2002 Justin Cormack <justin@street-vision.com>
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*
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* Release 0.02
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*
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* Based on advantechwdt.c which is based on wdt.c.
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* Original copyright messages:
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*
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* (c) Copyright 1996-1997 Alan Cox <alan@redhat.com>, All Rights Reserved.
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* http://www.redhat.com
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*
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* Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
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* warranty for any of this software. This material is provided
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* "AS-IS" and at no charge.
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*
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* (c) Copyright 1995 Alan Cox <alan@lxorguk.ukuu.org.uk>
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*
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*/
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#include <linux/module.h>
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#include <linux/moduleparam.h>
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#include <linux/miscdevice.h>
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#include <linux/watchdog.h>
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#include <linux/fs.h>
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#include <linux/ioport.h>
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#include <linux/notifier.h>
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#include <linux/reboot.h>
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#include <linux/init.h>
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#include <linux/spinlock.h>
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#include <linux/io.h>
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#include <linux/uaccess.h>
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#define WATCHDOG_NAME "Wafer 5823 WDT"
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#define PFX WATCHDOG_NAME ": "
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#define WD_TIMO 60 /* 60 sec default timeout */
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static unsigned long wafwdt_is_open;
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static char expect_close;
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static DEFINE_SPINLOCK(wafwdt_lock);
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/*
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* You must set these - there is no sane way to probe for this board.
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*
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* To enable, write the timeout value in seconds (1 to 255) to I/O
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* port WDT_START, then read the port to start the watchdog. To pat
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* the dog, read port WDT_STOP to stop the timer, then read WDT_START
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* to restart it again.
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*/
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static int wdt_stop = 0x843;
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static int wdt_start = 0x443;
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static int timeout = WD_TIMO; /* in seconds */
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module_param(timeout, int, 0);
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MODULE_PARM_DESC(timeout,
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"Watchdog timeout in seconds. 1 <= timeout <= 255, default="
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__MODULE_STRING(WD_TIMO) ".");
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static int nowayout = WATCHDOG_NOWAYOUT;
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module_param(nowayout, int, 0);
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MODULE_PARM_DESC(nowayout,
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"Watchdog cannot be stopped once started (default="
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__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
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static void wafwdt_ping(void)
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{
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/* pat watchdog */
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spin_lock(&wafwdt_lock);
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inb_p(wdt_stop);
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inb_p(wdt_start);
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spin_unlock(&wafwdt_lock);
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}
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static void wafwdt_start(void)
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{
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/* start up watchdog */
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outb_p(timeout, wdt_start);
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inb_p(wdt_start);
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}
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static void wafwdt_stop(void)
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{
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/* stop watchdog */
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inb_p(wdt_stop);
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}
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static ssize_t wafwdt_write(struct file *file, const char __user *buf,
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size_t count, loff_t *ppos)
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{
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/* See if we got the magic character 'V' and reload the timer */
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if (count) {
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if (!nowayout) {
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size_t i;
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/* In case it was set long ago */
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expect_close = 0;
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/* scan to see whether or not we got the magic
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character */
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for (i = 0; i != count; i++) {
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char c;
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if (get_user(c, buf + i))
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return -EFAULT;
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if (c == 'V')
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expect_close = 42;
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}
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}
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/* Well, anyhow someone wrote to us, we should
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return that favour */
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wafwdt_ping();
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}
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return count;
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}
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static long wafwdt_ioctl(struct file *file, unsigned int cmd,
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unsigned long arg)
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{
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int new_timeout;
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void __user *argp = (void __user *)arg;
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int __user *p = argp;
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static const struct watchdog_info ident = {
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.options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT |
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WDIOF_MAGICCLOSE,
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.firmware_version = 1,
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.identity = "Wafer 5823 WDT",
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};
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switch (cmd) {
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case WDIOC_GETSUPPORT:
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if (copy_to_user(argp, &ident, sizeof(ident)))
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return -EFAULT;
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break;
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case WDIOC_GETSTATUS:
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case WDIOC_GETBOOTSTATUS:
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return put_user(0, p);
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case WDIOC_SETOPTIONS:
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{
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int options, retval = -EINVAL;
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if (get_user(options, p))
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return -EFAULT;
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if (options & WDIOS_DISABLECARD) {
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wafwdt_start();
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retval = 0;
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}
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if (options & WDIOS_ENABLECARD) {
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wafwdt_stop();
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retval = 0;
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}
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return retval;
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}
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case WDIOC_KEEPALIVE:
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wafwdt_ping();
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break;
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case WDIOC_SETTIMEOUT:
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if (get_user(new_timeout, p))
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return -EFAULT;
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if ((new_timeout < 1) || (new_timeout > 255))
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return -EINVAL;
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timeout = new_timeout;
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wafwdt_stop();
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wafwdt_start();
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/* Fall */
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case WDIOC_GETTIMEOUT:
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return put_user(timeout, p);
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default:
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return -ENOTTY;
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}
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return 0;
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}
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static int wafwdt_open(struct inode *inode, struct file *file)
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{
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if (test_and_set_bit(0, &wafwdt_is_open))
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return -EBUSY;
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/*
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* Activate
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*/
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wafwdt_start();
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return nonseekable_open(inode, file);
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}
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static int wafwdt_close(struct inode *inode, struct file *file)
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{
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if (expect_close == 42)
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wafwdt_stop();
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else {
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printk(KERN_CRIT PFX
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"WDT device closed unexpectedly. WDT will not stop!\n");
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wafwdt_ping();
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}
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clear_bit(0, &wafwdt_is_open);
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expect_close = 0;
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return 0;
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}
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/*
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* Notifier for system down
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*/
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static int wafwdt_notify_sys(struct notifier_block *this, unsigned long code,
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void *unused)
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{
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if (code == SYS_DOWN || code == SYS_HALT)
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wafwdt_stop();
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return NOTIFY_DONE;
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}
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/*
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* Kernel Interfaces
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*/
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static const struct file_operations wafwdt_fops = {
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.owner = THIS_MODULE,
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.llseek = no_llseek,
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.write = wafwdt_write,
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.unlocked_ioctl = wafwdt_ioctl,
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.open = wafwdt_open,
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.release = wafwdt_close,
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};
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static struct miscdevice wafwdt_miscdev = {
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.minor = WATCHDOG_MINOR,
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.name = "watchdog",
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.fops = &wafwdt_fops,
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};
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/*
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* The WDT needs to learn about soft shutdowns in order to
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* turn the timebomb registers off.
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*/
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static struct notifier_block wafwdt_notifier = {
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.notifier_call = wafwdt_notify_sys,
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};
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static int __init wafwdt_init(void)
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{
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int ret;
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printk(KERN_INFO
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"WDT driver for Wafer 5823 single board computer initialising.\n");
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if (timeout < 1 || timeout > 255) {
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timeout = WD_TIMO;
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printk(KERN_INFO PFX
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"timeout value must be 1 <= x <= 255, using %d\n",
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timeout);
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}
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if (wdt_stop != wdt_start) {
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if (!request_region(wdt_stop, 1, "Wafer 5823 WDT")) {
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printk(KERN_ERR PFX
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"I/O address 0x%04x already in use\n",
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wdt_stop);
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ret = -EIO;
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goto error;
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}
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}
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if (!request_region(wdt_start, 1, "Wafer 5823 WDT")) {
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printk(KERN_ERR PFX "I/O address 0x%04x already in use\n",
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wdt_start);
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ret = -EIO;
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goto error2;
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}
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ret = register_reboot_notifier(&wafwdt_notifier);
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if (ret != 0) {
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printk(KERN_ERR PFX
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"cannot register reboot notifier (err=%d)\n", ret);
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goto error3;
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}
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ret = misc_register(&wafwdt_miscdev);
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if (ret != 0) {
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printk(KERN_ERR PFX
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"cannot register miscdev on minor=%d (err=%d)\n",
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WATCHDOG_MINOR, ret);
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goto error4;
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}
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printk(KERN_INFO PFX "initialized. timeout=%d sec (nowayout=%d)\n",
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timeout, nowayout);
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return ret;
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error4:
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unregister_reboot_notifier(&wafwdt_notifier);
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error3:
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release_region(wdt_start, 1);
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error2:
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if (wdt_stop != wdt_start)
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release_region(wdt_stop, 1);
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error:
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return ret;
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}
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static void __exit wafwdt_exit(void)
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{
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misc_deregister(&wafwdt_miscdev);
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unregister_reboot_notifier(&wafwdt_notifier);
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if (wdt_stop != wdt_start)
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release_region(wdt_stop, 1);
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release_region(wdt_start, 1);
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}
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module_init(wafwdt_init);
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module_exit(wafwdt_exit);
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MODULE_AUTHOR("Justin Cormack");
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MODULE_DESCRIPTION("ICP Wafer 5823 Single Board Computer WDT driver");
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MODULE_LICENSE("GPL");
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MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
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/* end of wafer5823wdt.c */
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