[ARM] 4495/1: iop: combined watchdog timer driver for iop3xx and iop13xx

In order for this driver to be shared across the iop architectures the
iop3xx and iop13xx header files are modified to present a common interface
for the iop_wdt driver.

Details:
* iop13xx supports disabling the timer while iop3xx does not.  This requires
  a few 'compatibility' definitions in include/asm-arm/hardware/iop3xx.h to
  preclude adding #ifdef CONFIG_ARCH_IOP13XX blocks to the driver code.
* The heartbeat interval is derived from the internal bus clock rate, so this
  this patch also exports the tick rate to the iop_wdt driver.

Cc: Curt Bruns <curt.e.bruns@intel.com>
Cc: Peter Milne <peter.milne@d-tacq.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: Wim Van Sebroeck <wim@iguana.be>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 262 insertions, 0 deletions

diff --git a/drivers/char/watchdog/iop_wdt.c b/drivers/char/watchdog/iop_wdt.c
new file mode 100644
index 000000000000..bbbd91af754d
--- /dev/null
+++ b/drivers/char/watchdog/iop_wdt.c
@@ -0,0 +1,262 @@
+/*
+ * drivers/char/watchdog/iop_wdt.c
+ *
+ * WDT driver for Intel I/O Processors
+ * Copyright (C) 2005, Intel Corporation.
+ *
+ * Based on ixp4xx driver, Copyright 2004 (c) MontaVista, Software, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
+ * Place - Suite 330, Boston, MA 02111-1307 USA.
+ *
+ *	Curt E Bruns <curt.e.bruns@intel.com>
+ *	Peter Milne <peter.milne@d-tacq.com>
+ *	Dan Williams <dan.j.williams@intel.com>
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/fs.h>
+#include <linux/init.h>
+#include <linux/device.h>
+#include <linux/miscdevice.h>
+#include <linux/watchdog.h>
+#include <linux/uaccess.h>
+#include <asm/hardware.h>
+
+static int nowayout = WATCHDOG_NOWAYOUT;
+static unsigned long wdt_status;
+static unsigned long boot_status;
+
+#define WDT_IN_USE		0
+#define WDT_OK_TO_CLOSE		1
+#define WDT_ENABLED		2
+
+static unsigned long iop_watchdog_timeout(void)
+{
+	return (0xffffffffUL / get_iop_tick_rate());
+}
+
+/**
+ * wdt_supports_disable - determine if we are accessing a iop13xx watchdog
+ * or iop3xx by whether it has a disable command
+ */
+static int wdt_supports_disable(void)
+{
+	int can_disable;
+
+	if (IOP_WDTCR_EN_ARM != IOP_WDTCR_DIS_ARM)
+		can_disable = 1;
+	else
+		can_disable = 0;
+
+	return can_disable;
+}
+
+static void wdt_enable(void)
+{
+	/* Arm and enable the Timer to starting counting down from 0xFFFF.FFFF
+	 * Takes approx. 10.7s to timeout
+	 */
+	write_wdtcr(IOP_WDTCR_EN_ARM);
+	write_wdtcr(IOP_WDTCR_EN);
+}
+
+/* returns 0 if the timer was successfully disabled */
+static int wdt_disable(void)
+{
+	/* Stop Counting */
+	if (wdt_supports_disable()) {
+		write_wdtcr(IOP_WDTCR_DIS_ARM);
+		write_wdtcr(IOP_WDTCR_DIS);
+		clear_bit(WDT_ENABLED, &wdt_status);
+		printk(KERN_INFO "WATCHDOG: Disabled\n");
+		return 0;
+	} else
+		return 1;
+}
+
+static int iop_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();
+
+	set_bit(WDT_ENABLED, &wdt_status);
+
+	return nonseekable_open(inode, file);
+}
+
+static ssize_t
+iop_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_enable();
+	}
+
+	return len;
+}
+
+static struct watchdog_info ident = {
+	.options = WDIOF_CARDRESET | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
+	.identity = "iop watchdog",
+};
+
+static int
+iop_wdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
+		  unsigned long arg)
+{
+	int options;
+	int ret = -ENOTTY;
+
+	switch (cmd) {
+	case WDIOC_GETSUPPORT:
+		if (copy_to_user
+		    ((struct watchdog_info *)arg, &ident, sizeof ident))
+			ret = -EFAULT;
+		else
+			ret = 0;
+		break;
+
+	case WDIOC_GETSTATUS:
+		ret = put_user(0, (int *)arg);
+		break;
+
+	case WDIOC_GETBOOTSTATUS:
+		ret = put_user(boot_status, (int *)arg);
+		break;
+
+	case WDIOC_GETTIMEOUT:
+		ret = put_user(iop_watchdog_timeout(), (int *)arg);
+		break;
+
+	case WDIOC_KEEPALIVE:
+		wdt_enable();
+		ret = 0;
+		break;
+
+	case WDIOC_SETOPTIONS:
+		if (get_user(options, (int *)arg))
+			return -EFAULT;
+
+		if (options & WDIOS_DISABLECARD) {
+			if (!nowayout) {
+				if (wdt_disable() == 0) {
+					set_bit(WDT_OK_TO_CLOSE, &wdt_status);
+					ret = 0;
+				} else
+					ret = -ENXIO;
+			} else
+				ret = 0;
+		}
+
+		if (options & WDIOS_ENABLECARD) {
+			wdt_enable();
+			ret = 0;
+		}
+		break;
+	}
+
+	return ret;
+}
+
+static int iop_wdt_release(struct inode *inode, struct file *file)
+{
+	int state = 1;
+	if (test_bit(WDT_OK_TO_CLOSE, &wdt_status))
+		if (test_bit(WDT_ENABLED, &wdt_status))
+			state = wdt_disable();
+
+	/* if the timer is not disbaled reload and notify that we are still
+	 * going down
+	 */
+	if (state != 0) {
+		wdt_enable();
+		printk(KERN_CRIT "WATCHDOG: Device closed unexpectedly - "
+		       "reset in %lu seconds\n", iop_watchdog_timeout());
+	}
+
+	clear_bit(WDT_IN_USE, &wdt_status);
+	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
+
+	return 0;
+}
+
+static const struct file_operations iop_wdt_fops = {
+	.owner = THIS_MODULE,
+	.llseek = no_llseek,
+	.write = iop_wdt_write,
+	.ioctl = iop_wdt_ioctl,
+	.open = iop_wdt_open,
+	.release = iop_wdt_release,
+};
+
+static struct miscdevice iop_wdt_miscdev = {
+	.minor = WATCHDOG_MINOR,
+	.name = "watchdog",
+	.fops = &iop_wdt_fops,
+};
+
+static int __init iop_wdt_init(void)
+{
+	int ret;
+
+	ret = misc_register(&iop_wdt_miscdev);
+	if (ret == 0)
+		printk("iop watchdog timer: timeout %lu sec\n",
+		       iop_watchdog_timeout());
+
+	/* check if the reset was caused by the watchdog timer */
+	boot_status = (read_rcsr() & IOP_RCSR_WDT) ? WDIOF_CARDRESET : 0;
+
+	/* Configure Watchdog Timeout to cause an Internal Bus (IB) Reset
+	 * NOTE: An IB Reset will Reset both cores in the IOP342
+	 */
+	write_wdtsr(IOP13XX_WDTCR_IB_RESET);
+
+	return ret;
+}
+
+static void __exit iop_wdt_exit(void)
+{
+	misc_deregister(&iop_wdt_miscdev);
+}
+
+module_init(iop_wdt_init);
+module_exit(iop_wdt_exit);
+
+module_param(nowayout, int, 0);
+MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
+
+MODULE_AUTHOR("Curt E Bruns <curt.e.bruns@intel.com>");
+MODULE_DESCRIPTION("iop watchdog timer driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);