From 3c6c80a04d6ca99c4f9fbb5e4f279bd644b2df48 Mon Sep 17 00:00:00 2001
From: Kurt Mahan <kmahan@freescale.com>
Date: Tue, 8 Jul 2008 14:10:46 -0600
Subject: [PATCH] Add Coldfire Watchdog support.

LTIBName: mcfv4e-watchdog
Signed-off-by: Kurt Mahan <kmahan@freescale.com>
---
 drivers/watchdog/Kconfig   |    9 ++
 drivers/watchdog/Makefile  |    1 +
 drivers/watchdog/mcf_wdt.c |  220 ++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 230 insertions(+), 0 deletions(-)
 create mode 100644 drivers/watchdog/mcf_wdt.c

--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -672,6 +672,15 @@ config TXX9_WDT
 
 # PARISC Architecture
 
+# ColdFire Architecture
+
+config COLDFIRE_WATCHDOG
+	tristate "ColdFire watchdog support"
+	depends on WATCHDOG
+	help
+	  To compile this driver as a module, choose M here: the
+	  module will be called softdog.
+
 # POWERPC Architecture
 
 config MPC5200_WDT
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -86,6 +86,7 @@ obj-$(CONFIG_SBC_EPX_C3_WATCHDOG) += sbc
 # M32R Architecture
 
 # M68K Architecture
+obj-$(CONFIG_COLDFIRE_WATCHDOG) += mcf_wdt.o
 
 # M68KNOMMU Architecture
 
--- /dev/null
+++ b/drivers/watchdog/mcf_wdt.c
@@ -0,0 +1,220 @@
+/*
+ * drivers/watchdog/mcf_wdt.c
+ *
+ * Watchdog driver for ColdFire processors
+ *
+ * Adapted from the IXP4xx watchdog driver.
+ * The original version carries these notices:
+ *
+ * Author: Deepak Saxena <dsaxena@plexity.net>
+ *
+ * Copyright 2004 (c) MontaVista, Software, Inc.
+ * Based on sa1100 driver, Copyright (C) 2000 Oleg Drokin <green@crimea.edu>
+ *
+ * This file is licensed under  the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/fs.h>
+#include <linux/miscdevice.h>
+#include <linux/watchdog.h>
+#include <linux/init.h>
+#include <linux/bitops.h>
+
+#include <asm-m68k/uaccess.h>
+#include <asm-m68k/coldfire.h>
+#include <asm-m68k/m5485gpt.h>
+
+static int nowayout;
+static unsigned int heartbeat = 30;	/* (secs) Default is 0.5 minute */
+static unsigned long wdt_status;
+
+#define	WDT_IN_USE		0
+#define	WDT_OK_TO_CLOSE		1
+
+static unsigned long wdt_tick_rate;
+
+static void
+wdt_enable(void)
+{
+	MCF_GPT_GMS0 = 0;
+	MCF_GPT_GCIR0 =  MCF_GPT_GCIR_PRE(heartbeat*wdt_tick_rate) |
+				MCF_GPT_GCIR_CNT(0xffff);
+	MCF_GPT_GMS0 = MCF_GPT_GMS_OCPW(0xA5) | MCF_GPT_GMS_WDEN |
+				MCF_GPT_GMS_CE | MCF_GPT_GMS_TMS_GPIO;
+}
+
+static void
+wdt_disable(void)
+{
+	MCF_GPT_GMS0 = 0;
+}
+
+static void
+wdt_keepalive(void)
+{
+	MCF_GPT_GMS0 = MCF_GPT_GMS_OCPW(0xA5) | MCF_GPT_GMS0;
+}
+
+static int
+mcf_wdt_open(struct inode *inode, struct file *file)
+{
+	if (test_and_set_bit(WDT_IN_USE, &wdt_status))
+		return -EBUSY;
+
+	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
+
+	wdt_enable();
+
+	return nonseekable_open(inode, file);
+}
+
+static ssize_t
+mcf_wdt_write(struct file *file, const char *data, size_t len, loff_t *ppos)
+{
+	if (len) {
+		if (!nowayout) {
+			size_t i;
+
+			clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
+
+			for (i = 0; i != len; i++) {
+				char c;
+
+				if (get_user(c, data + i))
+					return -EFAULT;
+				if (c == 'V')
+					set_bit(WDT_OK_TO_CLOSE, &wdt_status);
+			}
+		}
+		wdt_keepalive();
+	}
+
+	return len;
+}
+
+
+static struct watchdog_info ident = {
+	.options	= WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT |
+				WDIOF_KEEPALIVEPING,
+	.identity	= "Coldfire Watchdog",
+};
+
+static int
+mcf_wdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
+			unsigned long arg)
+{
+	int ret = -ENOIOCTLCMD;
+	int time;
+
+	switch (cmd) {
+	case WDIOC_GETSUPPORT:
+		ret = copy_to_user((struct watchdog_info *)arg, &ident,
+				   sizeof(ident)) ? -EFAULT : 0;
+		break;
+
+	case WDIOC_GETSTATUS:
+		ret = put_user(0, (int *)arg);
+		break;
+
+	case WDIOC_GETBOOTSTATUS:
+		ret = put_user(0, (int *)arg);
+		break;
+
+	case WDIOC_SETTIMEOUT:
+		ret = get_user(time, (int *)arg);
+		if (ret)
+			break;
+
+		if (time <= 0 || time > 30) {
+			ret = -EINVAL;
+			break;
+		}
+
+		heartbeat = time;
+		wdt_enable();
+		/* Fall through */
+
+	case WDIOC_GETTIMEOUT:
+		ret = put_user(heartbeat, (int *)arg);
+		break;
+
+	case WDIOC_KEEPALIVE:
+		wdt_keepalive();
+		ret = 0;
+		break;
+	}
+
+	return ret;
+}
+
+static int
+mcf_wdt_release(struct inode *inode, struct file *file)
+{
+	if (test_bit(WDT_OK_TO_CLOSE, &wdt_status)) {
+		wdt_disable();
+	} else {
+		printk(KERN_CRIT "WATCHDOG: Device closed unexpectdly - "
+					"timer will not stop\n");
+	}
+
+	clear_bit(WDT_IN_USE, &wdt_status);
+	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
+
+	return 0;
+}
+
+
+static struct file_operations mcf_wdt_fops = {
+	.owner		= THIS_MODULE,
+	.llseek		= no_llseek,
+	.write		= mcf_wdt_write,
+	.ioctl		= mcf_wdt_ioctl,
+	.open		= mcf_wdt_open,
+	.release	= mcf_wdt_release,
+};
+
+static struct miscdevice mcf_wdt_miscdev = {
+	.minor		= WATCHDOG_MINOR,
+	.name		= "watchdog",
+	.fops		= &mcf_wdt_fops,
+};
+
+static int __init mcf_wdt_init(void)
+{
+	wdt_tick_rate = MCF_BUSCLK/0xffff;
+#ifdef CONFIG_WATCHDOG_NOWAYOUT
+	nowayout = 1;
+#else
+	nowayout = 0;
+#endif
+	printk("ColdFire watchdog driver is loaded.\n");
+
+	return misc_register(&mcf_wdt_miscdev);
+}
+
+static void __exit mcf_wdt_exit(void)
+{
+	misc_deregister(&mcf_wdt_miscdev);
+}
+
+module_init(mcf_wdt_init);
+module_exit(mcf_wdt_exit);
+
+MODULE_AUTHOR("Deepak Saxena");
+MODULE_DESCRIPTION("ColdFire Watchdog");
+
+module_param(heartbeat, int, 0);
+MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds (default 60s)");
+
+module_param(nowayout, int, 0);
+MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
+
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
+
