patch-2.4.13 linux/drivers/char/ib700wdt.c

• Lines: 273
• Date: Thu Oct 11 09:07:00 2001
• Orig file: v2.4.12/linux/drivers/char/ib700wdt.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.4.12/linux/drivers/char/ib700wdt.c linux/drivers/char/ib700wdt.c
@@ -0,0 +1,272 @@
+/*
+ *	IB700 Single Board Computer WDT driver for Linux 2.4.x
+ *
+ *	(c) Copyright 2001 Charles Howes <chowes@vsol.net>
+ *
+ *      Based on advantechwdt.c which is based on acquirewdt.c which
+ *       is based on wdt.c.
+ *
+ *	(c) Copyright 2000-2001 Marek Michalkiewicz <marekm@linux.org.pl>
+ *
+ *	Based on acquirewdt.c which is based on wdt.c.
+ *	Original copyright messages:
+ *
+ *	(c) Copyright 1996 Alan Cox <alan@redhat.com>, 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 <alan@redhat.com>
+ *
+ */
+
+#include <linux/config.h>
+#include <linux/module.h>
+#include <linux/version.h>
+#include <linux/types.h>
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/miscdevice.h>
+#include <linux/watchdog.h>
+#include <linux/slab.h>
+#include <linux/ioport.h>
+#include <linux/fcntl.h>
+#include <asm/io.h>
+#include <asm/uaccess.h>
+#include <asm/system.h>
+#include <linux/notifier.h>
+#include <linux/reboot.h>
+#include <linux/init.h>
+#include <linux/spinlock.h>
+#include <linux/smp_lock.h>
+
+static int ibwdt_is_open;
+static spinlock_t ibwdt_lock;
+
+/*
+ *
+ * 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
+ *
+ */
+
+#define WDT_STOP 0x441
+#define WDT_START 0x443
+
+#define WD_TIMO 0		/* 30 seconds +/- 20%, from table */
+
+/*
+ *	Kernel methods.
+ */
+
+static void
+ibwdt_ping(void)
+{
+	/* Write a watchdog value */
+	outb_p(WD_TIMO, WDT_START);
+}
+
+static ssize_t
+ibwdt_write(struct file *file, const char *buf, size_t count, loff_t *ppos)
+{
+	/*  Can't seek (pwrite) on this device  */
+	if (ppos != &file->f_pos)
+		return -ESPIPE;
+
+	if (count) {
+		ibwdt_ping();
+		return 1;
+	}
+	return 0;
+}
+
+static ssize_t
+ibwdt_read(struct file *file, char *buf, size_t count, loff_t *ppos)
+{
+	return -EINVAL;
+}
+
+static int
+ibwdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
+	  unsigned long arg)
+{
+	static struct watchdog_info ident = {
+		WDIOF_KEEPALIVEPING, 1, "IB700 WDT"
+	};
+
+	switch (cmd) {
+	case WDIOC_GETSUPPORT:
+	  if (copy_to_user((struct watchdog_info *)arg, &ident, sizeof(ident)))
+	    return -EFAULT;
+	  break;
+
+	case WDIOC_GETSTATUS:
+	  if (copy_to_user((int *)arg, &ibwdt_is_open,  sizeof(int)))
+	    return -EFAULT;
+	  break;
+
+	case WDIOC_KEEPALIVE:
+	  ibwdt_ping();
+	  break;
+
+	default:
+	  return -ENOTTY;
+	}
+	return 0;
+}
+
+static int
+ibwdt_open(struct inode *inode, struct file *file)
+{
+	switch (MINOR(inode->i_rdev)) {
+		case WATCHDOG_MINOR:
+			spin_lock(&ibwdt_lock);
+			if (ibwdt_is_open) {
+				spin_unlock(&ibwdt_lock);
+				return -EBUSY;
+			}
+			/*
+			 *	Activate
+			 */
+
+			ibwdt_is_open = 1;
+			ibwdt_ping();
+			spin_unlock(&ibwdt_lock);
+			return 0;
+		default:
+			return -ENODEV;
+	}
+}
+
+static int
+ibwdt_close(struct inode *inode, struct file *file)
+{
+	lock_kernel();
+	if (MINOR(inode->i_rdev) == WATCHDOG_MINOR) {
+		spin_lock(&ibwdt_lock);
+#ifndef CONFIG_WATCHDOG_NOWAYOUT
+		outb_p(WD_TIMO, WDT_STOP);
+#endif
+		ibwdt_is_open = 0;
+		spin_unlock(&ibwdt_lock);
+	}
+	unlock_kernel();
+	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(WD_TIMO, WDT_STOP);
+	}
+	return NOTIFY_DONE;
+}
+
+/*
+ *	Kernel Interfaces
+ */
+
+static struct file_operations ibwdt_fops = {
+	owner:		THIS_MODULE,
+	read:		ibwdt_read,
+	write:		ibwdt_write,
+	ioctl:		ibwdt_ioctl,
+	open:		ibwdt_open,
+	release:	ibwdt_close,
+};
+
+static struct miscdevice ibwdt_miscdev = {
+	WATCHDOG_MINOR,
+	"watchdog",
+	&ibwdt_fops
+};
+
+/*
+ *	The WDT needs to learn about soft shutdowns in order to
+ *	turn the timebomb registers off.
+ */
+
+static struct notifier_block ibwdt_notifier = {
+	ibwdt_notify_sys,
+	NULL,
+	0
+};
+
+static int __init
+ibwdt_init(void)
+{
+	printk("WDT driver for IB700 single board computer initialising.\n");
+
+	spin_lock_init(&ibwdt_lock);
+	misc_register(&ibwdt_miscdev);
+#if WDT_START != WDT_STOP
+	request_region(WDT_STOP, 1, "IB700 WDT");
+#endif
+	request_region(WDT_START, 1, "IB700 WDT");
+	register_reboot_notifier(&ibwdt_notifier);
+	return 0;
+}
+
+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 <chowes@vsol.net>");
+MODULE_DESCRIPTION("IB700 SBC watchdog driver");
+MODULE_LICENSE("GPL");
+
+/* end of ib700wdt.c */