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path: root/drivers/char/watchdog/ib700wdt.c
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Diffstat (limited to 'drivers/char/watchdog/ib700wdt.c')
-rw-r--r--drivers/char/watchdog/ib700wdt.c352
1 files changed, 352 insertions, 0 deletions
diff --git a/drivers/char/watchdog/ib700wdt.c b/drivers/char/watchdog/ib700wdt.c
new file mode 100644
index 00000000000..d974f16e84d
--- /dev/null
+++ b/drivers/char/watchdog/ib700wdt.c
@@ -0,0 +1,352 @@
+/*
+ * IB700 Single Board Computer WDT driver
+ *
+ * (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>
+ *
+ * 14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com>
+ * Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT
+ * Added timeout module option to override default
+ *
+ */
+
+#include <linux/config.h>
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/miscdevice.h>
+#include <linux/watchdog.h>
+#include <linux/ioport.h>
+#include <linux/notifier.h>
+#include <linux/fs.h>
+#include <linux/reboot.h>
+#include <linux/init.h>
+#include <linux/spinlock.h>
+#include <linux/moduleparam.h>
+
+#include <asm/io.h>
+#include <asm/uaccess.h>
+#include <asm/system.h>
+
+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;
+
+#ifdef CONFIG_WATCHDOG_NOWAYOUT
+static int nowayout = 1;
+#else
+static int nowayout = 0;
+#endif
+
+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 <chowes@vsol.net>");
+MODULE_DESCRIPTION("IB700 SBC watchdog driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
+
+/* end of ib700wdt.c */
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