1 files changed, 329 insertions, 0 deletions
diff --git a/drivers/watchdog/acquirewdt.c b/drivers/watchdog/acquirewdt.c
new file mode 100644
index 0000000000..53b04abd55
--- /dev/null
+++ b/drivers/watchdog/acquirewdt.c
@@ -0,0 +1,329 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ *	Acquire Single Board Computer Watchdog Timer driver
+ *
+ *	Based on wdt.c. Original copyright messages:
+ *
+ *	(c) Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>,
+ *						All Rights Reserved.
+ *
+ *	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
+ *	    Can't add timeout - driver doesn't allow changing value
+ */
+
+/*
+ *	Theory of Operation:
+ *		The Watch-Dog Timer is provided to ensure that standalone
+ *		Systems can always recover from catastrophic conditions that
+ *		caused the CPU to crash. This condition may have occurred by
+ *		external EMI or a software bug. When the CPU stops working
+ *		correctly, hardware on the board will either perform a hardware
+ *		reset (cold boot) or a non-maskable interrupt (NMI) to bring the
+ *		system back to a known state.
+ *
+ *		The Watch-Dog Timer is controlled by two I/O Ports.
+ *		  443 hex	- Read	- Enable or refresh the Watch-Dog Timer
+ *		  043 hex	- Read	- Disable the Watch-Dog Timer
+ *
+ *		To enable the Watch-Dog Timer, a read from I/O port 443h must
+ *		be performed. This will enable and activate the countdown timer
+ *		which will eventually time out and either reset the CPU or cause
+ *		an NMI depending on the setting of a jumper. To ensure that this
+ *		reset condition does not occur, the Watch-Dog Timer must be
+ *		periodically refreshed by reading the same I/O port 443h.
+ *		The Watch-Dog Timer is disabled by reading I/O port 043h.
+ *
+ *		The Watch-Dog Timer Time-Out Period is set via jumpers.
+ *		It can be 1, 2, 10, 20, 110 or 220 seconds.
+ */
+
+/*
+ *	Includes, defines, variables, module parameters, ...
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+/* Includes */
+#include <linux/module.h>		/* For module specific items */
+#include <linux/moduleparam.h>		/* For new moduleparam's */
+#include <linux/types.h>		/* For standard types (like size_t) */
+#include <linux/errno.h>		/* For the -ENODEV/... values */
+#include <linux/kernel.h>		/* For printk/panic/... */
+#include <linux/miscdevice.h>		/* For struct miscdevice */
+#include <linux/watchdog.h>		/* For the watchdog specific items */
+#include <linux/fs.h>			/* For file operations */
+#include <linux/ioport.h>		/* For io-port access */
+#include <linux/platform_device.h>	/* For platform_driver framework */
+#include <linux/init.h>			/* For __init/__exit/... */
+#include <linux/uaccess.h>		/* For copy_to_user/put_user/... */
+#include <linux/io.h>			/* For inb/outb/... */
+
+/* Module information */
+#define DRV_NAME "acquirewdt"
+#define WATCHDOG_NAME "Acquire WDT"
+/* There is no way to see what the correct time-out period is */
+#define WATCHDOG_HEARTBEAT 0
+
+/* internal variables */
+/* the watchdog platform device */
+static struct platform_device *acq_platform_device;
+static unsigned long acq_is_open;
+static char expect_close;
+
+/* module parameters */
+/* You must set this - there is no sane way to probe for this board. */
+static int wdt_stop = 0x43;
+module_param(wdt_stop, int, 0);
+MODULE_PARM_DESC(wdt_stop, "Acquire WDT 'stop' io port (default 0x43)");
+
+/* You must set this - there is no sane way to probe for this board. */
+static int wdt_start = 0x443;
+module_param(wdt_start, int, 0);
+MODULE_PARM_DESC(wdt_start, "Acquire WDT 'start' io port (default 0x443)");
+
+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 acq_keepalive(void)
+{
+	/* Write a watchdog value */
+	inb_p(wdt_start);
+}
+
+static void acq_stop(void)
+{
+	/* Turn the card off */
+	inb_p(wdt_stop);
+}
+
+/*
+ *	/dev/watchdog handling
+ */
+
+static ssize_t acq_write(struct file *file, const char __user *buf,
+						size_t count, loff_t *ppos)
+{
+	/* See if we got the magic character 'V' and reload the timer */
+	if (count) {
+		if (!nowayout) {
+			size_t i;
+			/* note: just in case someone wrote the magic character
+			   five months ago... */
+			expect_close = 0;
+			/* scan to see whether or not we got the
+			   magic character */
+			for (i = 0; i != count; i++) {
+				char c;
+				if (get_user(c, buf + i))
+					return -EFAULT;
+				if (c == 'V')
+					expect_close = 42;
+			}
+		}
+		/* Well, anyhow someone wrote to us, we should
+				return that favour */
+		acq_keepalive();
+	}
+	return count;
+}
+
+static long acq_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+	int options, retval = -EINVAL;
+	void __user *argp = (void __user *)arg;
+	int __user *p = argp;
+	static const struct watchdog_info ident = {
+		.options = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
+		.firmware_version = 1,
+		.identity = WATCHDOG_NAME,
+	};
+
+	switch (cmd) {
+	case WDIOC_GETSUPPORT:
+		return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
+
+	case WDIOC_GETSTATUS:
+	case WDIOC_GETBOOTSTATUS:
+		return put_user(0, p);
+
+	case WDIOC_SETOPTIONS:
+	{
+		if (get_user(options, p))
+			return -EFAULT;
+		if (options & WDIOS_DISABLECARD) {
+			acq_stop();
+			retval = 0;
+		}
+		if (options & WDIOS_ENABLECARD) {
+			acq_keepalive();
+			retval = 0;
+		}
+		return retval;
+	}
+	case WDIOC_KEEPALIVE:
+		acq_keepalive();
+		return 0;
+
+	case WDIOC_GETTIMEOUT:
+		return put_user(WATCHDOG_HEARTBEAT, p);
+
+	default:
+		return -ENOTTY;
+	}
+}
+
+static int acq_open(struct inode *inode, struct file *file)
+{
+	if (test_and_set_bit(0, &acq_is_open))
+		return -EBUSY;
+
+	if (nowayout)
+		__module_get(THIS_MODULE);
+
+	/* Activate */
+	acq_keepalive();
+	return stream_open(inode, file);
+}
+
+static int acq_close(struct inode *inode, struct file *file)
+{
+	if (expect_close == 42) {
+		acq_stop();
+	} else {
+		pr_crit("Unexpected close, not stopping watchdog!\n");
+		acq_keepalive();
+	}
+	clear_bit(0, &acq_is_open);
+	expect_close = 0;
+	return 0;
+}
+
+/*
+ *	Kernel Interfaces
+ */
+
+static const struct file_operations acq_fops = {
+	.owner		= THIS_MODULE,
+	.llseek		= no_llseek,
+	.write		= acq_write,
+	.unlocked_ioctl	= acq_ioctl,
+	.compat_ioctl	= compat_ptr_ioctl,
+	.open		= acq_open,
+	.release	= acq_close,
+};
+
+static struct miscdevice acq_miscdev = {
+	.minor	= WATCHDOG_MINOR,
+	.name	= "watchdog",
+	.fops	= &acq_fops,
+};
+
+/*
+ *	Init & exit routines
+ */
+
+static int __init acq_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;
+	}
+	ret = misc_register(&acq_miscdev);
+	if (ret != 0) {
+		pr_err("cannot register miscdev on minor=%d (err=%d)\n",
+		       WATCHDOG_MINOR, ret);
+		goto unreg_regions;
+	}
+	pr_info("initialized. (nowayout=%d)\n", nowayout);
+
+	return 0;
+unreg_regions:
+	release_region(wdt_start, 1);
+unreg_stop:
+	if (wdt_stop != wdt_start)
+		release_region(wdt_stop, 1);
+out:
+	return ret;
+}
+
+static void acq_remove(struct platform_device *dev)
+{
+	misc_deregister(&acq_miscdev);
+	release_region(wdt_start, 1);
+	if (wdt_stop != wdt_start)
+		release_region(wdt_stop, 1);
+}
+
+static void acq_shutdown(struct platform_device *dev)
+{
+	/* Turn the WDT off if we have a soft shutdown */
+	acq_stop();
+}
+
+static struct platform_driver acquirewdt_driver = {
+	.remove_new	= acq_remove,
+	.shutdown	= acq_shutdown,
+	.driver		= {
+		.name	= DRV_NAME,
+	},
+};
+
+static int __init acq_init(void)
+{
+	int err;
+
+	pr_info("WDT driver for Acquire single board computer initialising\n");
+
+	acq_platform_device = platform_device_register_simple(DRV_NAME,
+								-1, NULL, 0);
+	if (IS_ERR(acq_platform_device))
+		return PTR_ERR(acq_platform_device);
+
+	err = platform_driver_probe(&acquirewdt_driver, acq_probe);
+	if (err)
+		goto unreg_platform_device;
+	return 0;
+
+unreg_platform_device:
+	platform_device_unregister(acq_platform_device);
+	return err;
+}
+
+static void __exit acq_exit(void)
+{
+	platform_device_unregister(acq_platform_device);
+	platform_driver_unregister(&acquirewdt_driver);
+	pr_info("Watchdog Module Unloaded\n");
+}
+
+module_init(acq_init);
+module_exit(acq_exit);
+
+MODULE_AUTHOR("David Woodhouse");
+MODULE_DESCRIPTION("Acquire Inc. Single Board Computer Watchdog Timer driver");
+MODULE_LICENSE("GPL");