Initial import

1 files changed, 271 insertions, 0 deletions

diff --git a/drivers/watchdog/scx200_wdt.c b/drivers/watchdog/scx200_wdt.c
new file mode 100644
index 000000000..836377cf9
--- /dev/null
+++ b/drivers/watchdog/scx200_wdt.c
@@ -0,0 +1,271 @@
+/* drivers/char/watchdog/scx200_wdt.c
+
+   National Semiconductor SCx200 Watchdog support
+
+   Copyright (c) 2001,2002 Christer Weinigel <wingel@nano-system.com>
+
+   Some code taken from:
+   National Semiconductor PC87307/PC97307 (ala SC1200) WDT driver
+   (c) Copyright 2002 Zwane Mwaikambo <zwane@commfireservices.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.
+
+   The author(s) of this software shall not be held liable for damages
+   of any nature resulting due to the use of this software. This
+   software is provided AS-IS with no warranties. */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/init.h>
+#include <linux/miscdevice.h>
+#include <linux/watchdog.h>
+#include <linux/notifier.h>
+#include <linux/reboot.h>
+#include <linux/fs.h>
+#include <linux/ioport.h>
+#include <linux/scx200.h>
+#include <linux/uaccess.h>
+#include <linux/io.h>
+
+#define DEBUG
+
+MODULE_AUTHOR("Christer Weinigel <wingel@nano-system.com>");
+MODULE_DESCRIPTION("NatSemi SCx200 Watchdog Driver");
+MODULE_LICENSE("GPL");
+
+static int margin = 60;		/* in seconds */
+module_param(margin, int, 0);
+MODULE_PARM_DESC(margin, "Watchdog margin in seconds");
+
+static bool nowayout = WATCHDOG_NOWAYOUT;
+module_param(nowayout, bool, 0);
+MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close");
+
+static u16 wdto_restart;
+static char expect_close;
+static unsigned long open_lock;
+static DEFINE_SPINLOCK(scx_lock);
+
+/* Bits of the WDCNFG register */
+#define W_ENABLE 0x00fa		/* Enable watchdog */
+#define W_DISABLE 0x0000	/* Disable watchdog */
+
+/* The scaling factor for the timer, this depends on the value of W_ENABLE */
+#define W_SCALE (32768/1024)
+
+static void scx200_wdt_ping(void)
+{
+	spin_lock(&scx_lock);
+	outw(wdto_restart, scx200_cb_base + SCx200_WDT_WDTO);
+	spin_unlock(&scx_lock);
+}
+
+static void scx200_wdt_update_margin(void)
+{
+	pr_info("timer margin %d seconds\n", margin);
+	wdto_restart = margin * W_SCALE;
+}
+
+static void scx200_wdt_enable(void)
+{
+	pr_debug("enabling watchdog timer, wdto_restart = %d\n", wdto_restart);
+
+	spin_lock(&scx_lock);
+	outw(0, scx200_cb_base + SCx200_WDT_WDTO);
+	outb(SCx200_WDT_WDSTS_WDOVF, scx200_cb_base + SCx200_WDT_WDSTS);
+	outw(W_ENABLE, scx200_cb_base + SCx200_WDT_WDCNFG);
+	spin_unlock(&scx_lock);
+
+	scx200_wdt_ping();
+}
+
+static void scx200_wdt_disable(void)
+{
+	pr_debug("disabling watchdog timer\n");
+
+	spin_lock(&scx_lock);
+	outw(0, scx200_cb_base + SCx200_WDT_WDTO);
+	outb(SCx200_WDT_WDSTS_WDOVF, scx200_cb_base + SCx200_WDT_WDSTS);
+	outw(W_DISABLE, scx200_cb_base + SCx200_WDT_WDCNFG);
+	spin_unlock(&scx_lock);
+}
+
+static int scx200_wdt_open(struct inode *inode, struct file *file)
+{
+	/* only allow one at a time */
+	if (test_and_set_bit(0, &open_lock))
+		return -EBUSY;
+	scx200_wdt_enable();
+
+	return nonseekable_open(inode, file);
+}
+
+static int scx200_wdt_release(struct inode *inode, struct file *file)
+{
+	if (expect_close != 42)
+		pr_warn("watchdog device closed unexpectedly, will not disable the watchdog timer\n");
+	else if (!nowayout)
+		scx200_wdt_disable();
+	expect_close = 0;
+	clear_bit(0, &open_lock);
+
+	return 0;
+}
+
+static int scx200_wdt_notify_sys(struct notifier_block *this,
+				      unsigned long code, void *unused)
+{
+	if (code == SYS_HALT || code == SYS_POWER_OFF)
+		if (!nowayout)
+			scx200_wdt_disable();
+
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block scx200_wdt_notifier = {
+	.notifier_call = scx200_wdt_notify_sys,
+};
+
+static ssize_t scx200_wdt_write(struct file *file, const char __user *data,
+				     size_t len, loff_t *ppos)
+{
+	/* check for a magic close character */
+	if (len) {
+		size_t i;
+
+		scx200_wdt_ping();
+
+		expect_close = 0;
+		for (i = 0; i < len; ++i) {
+			char c;
+			if (get_user(c, data + i))
+				return -EFAULT;
+			if (c == 'V')
+				expect_close = 42;
+		}
+
+		return len;
+	}
+
+	return 0;
+}
+
+static long scx200_wdt_ioctl(struct file *file, unsigned int cmd,
+							unsigned long arg)
+{
+	void __user *argp = (void __user *)arg;
+	int __user *p = argp;
+	static const struct watchdog_info ident = {
+		.identity = "NatSemi SCx200 Watchdog",
+		.firmware_version = 1,
+		.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
+						WDIOF_MAGICCLOSE,
+	};
+	int new_margin;
+
+	switch (cmd) {
+	case WDIOC_GETSUPPORT:
+		if (copy_to_user(argp, &ident, sizeof(ident)))
+			return -EFAULT;
+		return 0;
+	case WDIOC_GETSTATUS:
+	case WDIOC_GETBOOTSTATUS:
+		if (put_user(0, p))
+			return -EFAULT;
+		return 0;
+	case WDIOC_KEEPALIVE:
+		scx200_wdt_ping();
+		return 0;
+	case WDIOC_SETTIMEOUT:
+		if (get_user(new_margin, p))
+			return -EFAULT;
+		if (new_margin < 1)
+			return -EINVAL;
+		margin = new_margin;
+		scx200_wdt_update_margin();
+		scx200_wdt_ping();
+	case WDIOC_GETTIMEOUT:
+		if (put_user(margin, p))
+			return -EFAULT;
+		return 0;
+	default:
+		return -ENOTTY;
+	}
+}
+
+static const struct file_operations scx200_wdt_fops = {
+	.owner = THIS_MODULE,
+	.llseek = no_llseek,
+	.write = scx200_wdt_write,
+	.unlocked_ioctl = scx200_wdt_ioctl,
+	.open = scx200_wdt_open,
+	.release = scx200_wdt_release,
+};
+
+static struct miscdevice scx200_wdt_miscdev = {
+	.minor = WATCHDOG_MINOR,
+	.name = "watchdog",
+	.fops = &scx200_wdt_fops,
+};
+
+static int __init scx200_wdt_init(void)
+{
+	int r;
+
+	pr_debug("NatSemi SCx200 Watchdog Driver\n");
+
+	/* check that we have found the configuration block */
+	if (!scx200_cb_present())
+		return -ENODEV;
+
+	if (!request_region(scx200_cb_base + SCx200_WDT_OFFSET,
+			    SCx200_WDT_SIZE,
+			    "NatSemi SCx200 Watchdog")) {
+		pr_warn("watchdog I/O region busy\n");
+		return -EBUSY;
+	}
+
+	scx200_wdt_update_margin();
+	scx200_wdt_disable();
+
+	r = register_reboot_notifier(&scx200_wdt_notifier);
+	if (r) {
+		pr_err("unable to register reboot notifier\n");
+		release_region(scx200_cb_base + SCx200_WDT_OFFSET,
+				SCx200_WDT_SIZE);
+		return r;
+	}
+
+	r = misc_register(&scx200_wdt_miscdev);
+	if (r) {
+		unregister_reboot_notifier(&scx200_wdt_notifier);
+		release_region(scx200_cb_base + SCx200_WDT_OFFSET,
+				SCx200_WDT_SIZE);
+		return r;
+	}
+
+	return 0;
+}
+
+static void __exit scx200_wdt_cleanup(void)
+{
+	misc_deregister(&scx200_wdt_miscdev);
+	unregister_reboot_notifier(&scx200_wdt_notifier);
+	release_region(scx200_cb_base + SCx200_WDT_OFFSET,
+		       SCx200_WDT_SIZE);
+}
+
+module_init(scx200_wdt_init);
+module_exit(scx200_wdt_cleanup);
+
+/*
+    Local variables:
+	compile-command: "make -k -C ../.. SUBDIRS=drivers/char modules"
+	c-basic-offset: 8
+    End:
+*/