File-copy from v4.4.100

This is the result of 'cp' from a linux-stable tree with the 'v4.4.100'
tag checked out (commit 26d6298789e695c9f627ce49a7bbd2286405798a) on
git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git

Please refer to that tree for all history prior to this point.

Change-Id: I8a9ee2aea93cd29c52c847d0ce33091a73ae6afe
diff --git a/drivers/watchdog/advantechwdt.c b/drivers/watchdog/advantechwdt.c
new file mode 100644
index 0000000..7d7db0c
--- /dev/null
+++ b/drivers/watchdog/advantechwdt.c
@@ -0,0 +1,343 @@
+/*
+ *	Advantech Single Board Computer WDT driver
+ *
+ *	(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@lxorguk.ukuu.org.uk>,
+ *						All Rights Reserved.
+ *
+ *	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@lxorguk.ukuu.org.uk>
+ *
+ *	14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com>
+ *	    Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT
+ *
+ *	16-Oct-2002 Rob Radez <rob@osinvestor.com>
+ *	    Clean up ioctls, clean up init + exit, add expect close support,
+ *	    add wdt_start and wdt_stop as parameters.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/types.h>
+#include <linux/miscdevice.h>
+#include <linux/watchdog.h>
+#include <linux/fs.h>
+#include <linux/ioport.h>
+#include <linux/platform_device.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/uaccess.h>
+
+
+#define DRV_NAME "advantechwdt"
+#define WATCHDOG_NAME "Advantech WDT"
+#define WATCHDOG_TIMEOUT 60		/* 60 sec default timeout */
+
+/* the watchdog platform device */
+static struct platform_device *advwdt_platform_device;
+static unsigned long advwdt_is_open;
+static char adv_expect_close;
+
+/*
+ *	You must set these - there is no sane way to probe for this board.
+ *
+ *	To enable or restart, write the timeout value in seconds (1 to 63)
+ *	to I/O port wdt_start.  To disable, read I/O port wdt_stop.
+ *	Both are 0x443 for most boards (tested on a PCA-6276VE-00B1), but
+ *	check your manual (at least the PCA-6159 seems to be different -
+ *	the manual says wdt_stop is 0x43, not 0x443).
+ *	(0x43 is also a write-only control register for the 8254 timer!)
+ */
+
+static int wdt_stop = 0x443;
+module_param(wdt_stop, int, 0);
+MODULE_PARM_DESC(wdt_stop, "Advantech WDT 'stop' io port (default 0x443)");
+
+static int wdt_start = 0x443;
+module_param(wdt_start, int, 0);
+MODULE_PARM_DESC(wdt_start, "Advantech WDT 'start' io port (default 0x443)");
+
+static int timeout = WATCHDOG_TIMEOUT;	/* in seconds */
+module_param(timeout, int, 0);
+MODULE_PARM_DESC(timeout,
+	"Watchdog timeout in seconds. 1<= timeout <=63, default="
+		__MODULE_STRING(WATCHDOG_TIMEOUT) ".");
+
+static bool nowayout = WATCHDOG_NOWAYOUT;
+module_param(nowayout, bool, 0);
+MODULE_PARM_DESC(nowayout,
+	"Watchdog cannot be stopped once started (default="
+		__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
+
+/*
+ *	Watchdog Operations
+ */
+
+static void advwdt_ping(void)
+{
+	/* Write a watchdog value */
+	outb_p(timeout, wdt_start);
+}
+
+static void advwdt_disable(void)
+{
+	inb_p(wdt_stop);
+}
+
+static int advwdt_set_heartbeat(int t)
+{
+	if (t < 1 || t > 63)
+		return -EINVAL;
+	timeout = t;
+	return 0;
+}
+
+/*
+ *	/dev/watchdog handling
+ */
+
+static ssize_t advwdt_write(struct file *file, const char __user *buf,
+						size_t count, loff_t *ppos)
+{
+	if (count) {
+		if (!nowayout) {
+			size_t i;
+
+			adv_expect_close = 0;
+
+			for (i = 0; i != count; i++) {
+				char c;
+				if (get_user(c, buf + i))
+					return -EFAULT;
+				if (c == 'V')
+					adv_expect_close = 42;
+			}
+		}
+		advwdt_ping();
+	}
+	return count;
+}
+
+static long advwdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+	int new_timeout;
+	void __user *argp = (void __user *)arg;
+	int __user *p = argp;
+	static const struct watchdog_info ident = {
+		.options = WDIOF_KEEPALIVEPING |
+			   WDIOF_SETTIMEOUT |
+			   WDIOF_MAGICCLOSE,
+		.firmware_version = 1,
+		.identity = WATCHDOG_NAME,
+	};
+
+	switch (cmd) {
+	case WDIOC_GETSUPPORT:
+		if (copy_to_user(argp, &ident, sizeof(ident)))
+			return -EFAULT;
+		break;
+
+	case WDIOC_GETSTATUS:
+	case WDIOC_GETBOOTSTATUS:
+		return put_user(0, p);
+
+	case WDIOC_SETOPTIONS:
+	{
+		int options, retval = -EINVAL;
+
+		if (get_user(options, p))
+			return -EFAULT;
+		if (options & WDIOS_DISABLECARD) {
+			advwdt_disable();
+			retval = 0;
+		}
+		if (options & WDIOS_ENABLECARD) {
+			advwdt_ping();
+			retval = 0;
+		}
+		return retval;
+	}
+	case WDIOC_KEEPALIVE:
+		advwdt_ping();
+		break;
+
+	case WDIOC_SETTIMEOUT:
+		if (get_user(new_timeout, p))
+			return -EFAULT;
+		if (advwdt_set_heartbeat(new_timeout))
+			return -EINVAL;
+		advwdt_ping();
+		/* Fall */
+	case WDIOC_GETTIMEOUT:
+		return put_user(timeout, p);
+	default:
+		return -ENOTTY;
+	}
+	return 0;
+}
+
+static int advwdt_open(struct inode *inode, struct file *file)
+{
+	if (test_and_set_bit(0, &advwdt_is_open))
+		return -EBUSY;
+	/*
+	 *	Activate
+	 */
+
+	advwdt_ping();
+	return nonseekable_open(inode, file);
+}
+
+static int advwdt_close(struct inode *inode, struct file *file)
+{
+	if (adv_expect_close == 42) {
+		advwdt_disable();
+	} else {
+		pr_crit("Unexpected close, not stopping watchdog!\n");
+		advwdt_ping();
+	}
+	clear_bit(0, &advwdt_is_open);
+	adv_expect_close = 0;
+	return 0;
+}
+
+/*
+ *	Kernel Interfaces
+ */
+
+static const struct file_operations advwdt_fops = {
+	.owner		= THIS_MODULE,
+	.llseek		= no_llseek,
+	.write		= advwdt_write,
+	.unlocked_ioctl	= advwdt_ioctl,
+	.open		= advwdt_open,
+	.release	= advwdt_close,
+};
+
+static struct miscdevice advwdt_miscdev = {
+	.minor	= WATCHDOG_MINOR,
+	.name	= "watchdog",
+	.fops	= &advwdt_fops,
+};
+
+/*
+ *	Init & exit routines
+ */
+
+static int __init advwdt_probe(struct platform_device *dev)
+{
+	int ret;
+
+	if (wdt_stop != wdt_start) {
+		if (!request_region(wdt_stop, 1, WATCHDOG_NAME)) {
+			pr_err("I/O address 0x%04x already in use\n",
+			       wdt_stop);
+			ret = -EIO;
+			goto out;
+		}
+	}
+
+	if (!request_region(wdt_start, 1, WATCHDOG_NAME)) {
+		pr_err("I/O address 0x%04x already in use\n", wdt_start);
+		ret = -EIO;
+		goto unreg_stop;
+	}
+
+	/* Check that the heartbeat value is within it's range ;
+	 * if not reset to the default */
+	if (advwdt_set_heartbeat(timeout)) {
+		advwdt_set_heartbeat(WATCHDOG_TIMEOUT);
+		pr_info("timeout value must be 1<=x<=63, using %d\n", timeout);
+	}
+
+	ret = misc_register(&advwdt_miscdev);
+	if (ret != 0) {
+		pr_err("cannot register miscdev on minor=%d (err=%d)\n",
+		       WATCHDOG_MINOR, ret);
+		goto unreg_regions;
+	}
+	pr_info("initialized. timeout=%d sec (nowayout=%d)\n",
+		timeout, nowayout);
+out:
+	return ret;
+unreg_regions:
+	release_region(wdt_start, 1);
+unreg_stop:
+	if (wdt_stop != wdt_start)
+		release_region(wdt_stop, 1);
+	goto out;
+}
+
+static int advwdt_remove(struct platform_device *dev)
+{
+	misc_deregister(&advwdt_miscdev);
+	release_region(wdt_start, 1);
+	if (wdt_stop != wdt_start)
+		release_region(wdt_stop, 1);
+
+	return 0;
+}
+
+static void advwdt_shutdown(struct platform_device *dev)
+{
+	/* Turn the WDT off if we have a soft shutdown */
+	advwdt_disable();
+}
+
+static struct platform_driver advwdt_driver = {
+	.remove		= advwdt_remove,
+	.shutdown	= advwdt_shutdown,
+	.driver		= {
+		.name	= DRV_NAME,
+	},
+};
+
+static int __init advwdt_init(void)
+{
+	int err;
+
+	pr_info("WDT driver for Advantech single board computer initialising\n");
+
+	advwdt_platform_device = platform_device_register_simple(DRV_NAME,
+								-1, NULL, 0);
+	if (IS_ERR(advwdt_platform_device))
+		return PTR_ERR(advwdt_platform_device);
+
+	err = platform_driver_probe(&advwdt_driver, advwdt_probe);
+	if (err)
+		goto unreg_platform_device;
+
+	return 0;
+
+unreg_platform_device:
+	platform_device_unregister(advwdt_platform_device);
+	return err;
+}
+
+static void __exit advwdt_exit(void)
+{
+	platform_device_unregister(advwdt_platform_device);
+	platform_driver_unregister(&advwdt_driver);
+	pr_info("Watchdog Module Unloaded\n");
+}
+
+module_init(advwdt_init);
+module_exit(advwdt_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Marek Michalkiewicz <marekm@linux.org.pl>");
+MODULE_DESCRIPTION("Advantech Single Board Computer WDT driver");