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