add watchdog driver

Here is the driver for the hardware watchdog timer
in ADM5120 SoC. Patch is against current svn Kamikaze.

Here is only kernel driver. To activate watchdog you have
to use some userspace software writing to watchdog
device. I think there is one in busybox.

Signed-off-by: Ondrej Zajicek <santiago@crfreenet.org>

SVN-Revision: 9961

1 files changed, 210 insertions, 0 deletions

diff --git a/target/linux/adm5120/files/drivers/char/watchdog/adm5120_wdt.c b/target/linux/adm5120/files/drivers/char/watchdog/adm5120_wdt.c
new file mode 100644
index 0000000..982fe39
--- /dev/null
+++ b/target/linux/adm5120/files/drivers/char/watchdog/adm5120_wdt.c
@@ -0,0 +1,210 @@
+/*
+ *	ADM5120_WDT 0.01: Infineon ADM5120 SoC watchdog driver 
+ *	Copyright (c) Ondrej Zajicek <santiago@crfreenet.org>, 2007
+ *
+ *	based on
+ *
+ *	RC32434_WDT 0.01: IDT Interprise 79RC32434 watchdog driver
+ *
+ *	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.
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/fs.h>
+#include <linux/miscdevice.h>
+#include <linux/watchdog.h>
+
+#include <asm/bootinfo.h>
+
+#include <adm5120_info.h>
+#include <adm5120_defs.h>
+#include <adm5120_irq.h>
+#include <adm5120_switch.h>
+
+
+#define DEFAULT_TIMEOUT	15		/* (secs) Default is 15 seconds */
+#define MAX_TIMEOUT	327
+/* Max is 327 seconds, counter is 15-bit integer, step is 10 ms */
+
+#define NAME "adm5120_wdt"
+#define VERSION "0.1"
+
+static int expect_close = 0;
+static int access = 0;
+static unsigned int timeout = DEFAULT_TIMEOUT;
+
+static int nowayout = WATCHDOG_NOWAYOUT;
+module_param(nowayout, int, 0);
+MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
+MODULE_LICENSE("GPL");
+
+
+static inline void wdt_set_timeout(void)
+{
+	u32 val = (1 << 31) | (((timeout * 100) & 0x7FFF) << 16);
+	SW_WRITE_REG(WDOG0, val);
+}
+
+/* 
+   It looks like WDOG0-register-write don't modify counter,
+   but WDOG0-register-read resets counter.
+*/
+
+static inline void wdt_reset_counter(void)
+{
+	SW_READ_REG(WDOG0);
+}
+
+static inline void wdt_disable(void)
+{
+	SW_WRITE_REG(WDOG0, 0x7FFF0000);
+}
+
+
+ 
+static int wdt_open(struct inode *inode, struct file *file)
+{
+	/* Allow only one person to hold it open */
+	if (access)
+		return -EBUSY;
+
+	if (nowayout) {
+		__module_get(THIS_MODULE);
+	}
+
+	/* Activate timer */
+	wdt_reset_counter();
+	wdt_set_timeout();
+	printk(KERN_INFO NAME ": enabling watchdog timer\n");
+	access = 1;
+	return 0;
+}
+
+static int wdt_release(struct inode *inode, struct file *file)
+{
+	/*
+	 *	Shut off the timer.
+	 * 	Lock it in if it's a module and we set nowayout
+	 */
+	if (expect_close && (nowayout == 0)) {
+		wdt_disable();
+		printk(KERN_INFO NAME ": disabling watchdog timer\n");
+		module_put(THIS_MODULE);
+	} else {
+		printk(KERN_CRIT NAME ": device closed unexpectedly.  WDT will not stop!\n");
+	}
+	access = 0;
+	return 0;
+}
+
+static ssize_t wdt_write(struct file *file, const char *data, size_t len, loff_t *ppos)
+{
+	/* Refresh the timer. */
+	if (len) {
+		if (!nowayout) {
+			size_t i;
+
+			/* In case it was set long ago */
+			expect_close = 0;
+
+			for (i = 0; i != len; i++) {
+				char c;
+				if (get_user(c, data + i))
+					return -EFAULT;
+				if (c == 'V')
+					expect_close = 1;
+			}
+		}
+		wdt_reset_counter();
+		return len;
+	}
+	return 0;
+}
+
+static int wdt_ioctl(struct inode *inode, struct file *file,
+	unsigned int cmd, unsigned long arg)
+{
+	int new_timeout;
+	static struct watchdog_info ident = {
+		.options =		WDIOF_SETTIMEOUT |
+					WDIOF_KEEPALIVEPING |
+					WDIOF_MAGICCLOSE,
+		.firmware_version =	0,
+		.identity =		"ADM5120_WDT Watchdog",
+	};
+	switch (cmd) {
+		default:
+			return -ENOTTY;
+		case WDIOC_GETSUPPORT:
+			if(copy_to_user((struct watchdog_info *)arg, &ident, sizeof(ident)))
+				return -EFAULT;
+			return 0;
+		case WDIOC_GETSTATUS:
+		case WDIOC_GETBOOTSTATUS:
+			return put_user(0,(int *)arg);
+		case WDIOC_KEEPALIVE:
+			wdt_reset_counter();
+			return 0;
+		case WDIOC_SETTIMEOUT:
+			if (get_user(new_timeout, (int *)arg))
+				return -EFAULT;
+			if (new_timeout < 1)
+				return -EINVAL;
+			if (new_timeout > MAX_TIMEOUT)
+				return -EINVAL;
+			timeout = new_timeout;
+			wdt_set_timeout();
+			/* Fall */
+		case WDIOC_GETTIMEOUT:
+			return put_user(timeout, (int *)arg);
+	}
+}
+
+static struct file_operations wdt_fops = {
+	owner:		THIS_MODULE,
+	llseek:		no_llseek,
+	write:		wdt_write,
+	ioctl:		wdt_ioctl,
+	open:		wdt_open,
+	release:	wdt_release,
+};
+
+static struct miscdevice wdt_miscdev = {
+	minor:		WATCHDOG_MINOR,
+	name:		"watchdog",
+	fops:		&wdt_fops,
+};
+
+static char banner[] __initdata = KERN_INFO NAME ": Watchdog Timer version " VERSION "\n";
+
+static int __init watchdog_init(void)
+{
+	int ret;
+
+	/* There should be check for ADM5120 */
+	if (mips_machgroup != MACH_GROUP_ADM5120)
+		return -1;
+
+	ret = misc_register(&wdt_miscdev);
+
+	if (ret)
+		return ret;
+
+	wdt_disable();
+	printk(banner);
+
+	return 0;
+}
+
+static void __exit watchdog_exit(void)
+{
+	misc_deregister(&wdt_miscdev);
+}
+
+module_init(watchdog_init);
+module_exit(watchdog_exit);