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SubjectAT91SAM9/CAP9 watchdog driver
Driver to support the internal watchdog peripheral found on Atmel's
AT91SAM9 and AT91CAP9 processors (ARM).

Signed-off-by: Renaud Cerrato <r.cerrato@til-technologies.fr>
Signed-off-by: Andrew Victor <linux@maxim.org.za>
diff -urN linux-2.6.26-rc3.orig/drivers/watchdog/Kconfig linux-2.6.26-rc3/drivers/watchdog/Kconfig
--- linux-2.6.26-rc3.orig/drivers/watchdog/Kconfig 2008-05-24 17:24:22.000000000 +0200
+++ linux-2.6.26-rc3/drivers/watchdog/Kconfig 2008-06-01 18:28:27.000000000 +0200
@@ -66,6 +66,14 @@
Watchdog timer embedded into AT91RM9200 chips. This will reboot your
system when the timeout is reached.

+config AT91SAM9_WATCHDOG
+ tristate "AT91SAM9 / AT91CAP9 watchdog"
+ depends on ARCH_AT91 && !ARCH_AT91RM9200
+ select WATCHDOG_NOWAYOUT
+ help
+ Watchdog timer embedded into Atmel AT91SAM9 and AT91CAP9 processors.
+ This will reboot your system when the timeout is reached.
+
config 21285_WATCHDOG
tristate "DC21285 watchdog"
depends on FOOTBRIDGE
diff -urN linux-2.6.26-rc3.orig/drivers/watchdog/Makefile linux-2.6.26-rc3/drivers/watchdog/Makefile
--- linux-2.6.26-rc3.orig/drivers/watchdog/Makefile 2008-05-24 17:24:22.000000000 +0200
+++ linux-2.6.26-rc3/drivers/watchdog/Makefile 2008-06-01 18:04:40.000000000 +0200
@@ -26,6 +26,7 @@

# ARM Architecture
obj-$(CONFIG_AT91RM9200_WATCHDOG) += at91rm9200_wdt.o
+obj-$(CONFIG_AT91SAM9_WATCHDOG) += at91sam9_wdt.o
obj-$(CONFIG_OMAP_WATCHDOG) += omap_wdt.o
obj-$(CONFIG_21285_WATCHDOG) += wdt285.o
obj-$(CONFIG_977_WATCHDOG) += wdt977.o
diff -urN linux-2.6.26-rc3.orig/drivers/watchdog/at91sam9_wdt.c linux-2.6.26-rc3/drivers/watchdog/at91sam9_wdt.c
--- linux-2.6.26-rc3.orig/drivers/watchdog/at91sam9_wdt.c 1970-01-01 02:00:00.000000000 +0200
+++ linux-2.6.26-rc3/drivers/watchdog/at91sam9_wdt.c 2008-06-01 18:26:08.000000000 +0200
@@ -0,0 +1,263 @@
+/*
+ * Watchdog driver for Atmel AT91SAM9x processors.
+ *
+ * Copyright (C) 2007 Renaud CERRATO r.cerrato@til-technologies.fr
+ *
+ * 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.
+ */
+
+/*
+ * The Watchdog Timer Mode Register can be only written to once. If the
+ * timeout need to be set from Linux, be sure that the bootstrap or the
+ * bootloader doesn't write to this register.
+ */
+
+#include <linux/errno.h>
+#include <linux/fs.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/miscdevice.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/platform_device.h>
+#include <linux/types.h>
+#include <linux/watchdog.h>
+#include <linux/bitops.h>
+#include <linux/uaccess.h>
+
+#include <asm/arch/at91_wdt.h>
+
+
+#define WDT_MAX_TIME 16 /* seconds */
+
+static int wdt_timeout = -1; /* invalid */
+
+module_param(wdt_timeout, int, 0);
+MODULE_PARM_DESC(wdt_timeout, "Watchdog time in seconds. (default = disabled)");
+
+
+static unsigned long at91wdt_busy;
+
+/* ......................................................................... */
+
+/*
+ * Reload the watchdog timer. (ie, pat the watchdog)
+ */
+static inline void at91_wdt_reload(void)
+{
+ at91_sys_write(AT91_WDT_CR, AT91_WDT_KEY | AT91_WDT_WDRSTT);
+}
+
+/* ......................................................................... */
+
+/*
+ * Watchdog device is opened, and watchdog starts running.
+ */
+static int at91_wdt_open(struct inode *inode, struct file *file)
+{
+ if (test_and_set_bit(0, &at91wdt_busy))
+ return -EBUSY;
+
+ return nonseekable_open(inode, file);
+}
+
+/*
+ * Close the watchdog device.
+ */
+static int at91_wdt_close(struct inode *inode, struct file *file)
+{
+ clear_bit(0, &at91wdt_busy);
+ return 0;
+}
+
+/*
+ * Change the watchdog time interval.
+ */
+static int at91_wdt_settimeout(int new_time)
+{
+ unsigned int reg, mr;
+ /*
+ * All counting occurs at SLOW_CLOCK / 128 = 256 Hz
+ *
+ * Since WDV is a 12-bit counter, the maximum period is
+ * 4096 / 256 = 16 seconds.
+ */
+ if ((new_time <= 0) || (new_time > WDT_MAX_TIME))
+ return -EINVAL;
+
+ wdt_timeout = new_time;
+
+ /* Program the Watchdog */
+ reg = AT91_WDT_WDRSTEN /* causes watchdog reset */
+ | AT91_WDT_WDRPROC /* causes processor reset */
+ | AT91_WDT_WDDBGHLT /* disabled in debug mode */
+ | AT91_WDT_WDD /* restart at any time */
+ | (((wdt_timeout * 256) - 1) & AT91_WDT_WDV);
+ at91_sys_write(AT91_WDT_MR, reg);
+
+ /* Check if watchdog could be programmed */
+ mr = at91_sys_read(AT91_WDT_MR);
+ if (mr != reg) {
+ printk(KERN_ERR "at91sam9_wdt: Watchdog already programmed.\n");
+ return -EIO;
+ }
+
+ at91_wdt_reload();
+
+ printk(KERN_INFO "AT91SAM9 Watchdog enabled (%d seconds, nowayout)\n",
+ wdt_timeout);
+ return 0;
+}
+
+static struct watchdog_info at91_wdt_info = {
+ .identity = "at91sam9 watchdog",
+ .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
+};
+
+/*
+ * Handle commands from user-space.
+ */
+static long at91_wdt_ioctl(struct file *file, unsigned int cmd,
+ unsigned long arg)
+{
+ void __user *argp = (void __user *)arg;
+ int __user *p = argp;
+ int new_value, err;
+
+ switch (cmd) {
+ case WDIOC_KEEPALIVE:
+ at91_wdt_reload(); /* pat the watchdog */
+ return 0;
+
+ case WDIOC_GETSUPPORT:
+ return copy_to_user(argp, &at91_wdt_info,
+ sizeof(at91_wdt_info)) ? -EFAULT : 0;
+
+ case WDIOC_SETTIMEOUT:
+ if (get_user(new_value, p))
+ return -EFAULT;
+
+ err = at91_wdt_settimeout(new_value);
+ if (err)
+ return err;
+
+ return put_user(wdt_timeout, p);
+
+ case WDIOC_GETTIMEOUT:
+ return put_user(wdt_timeout, p);
+
+ case WDIOC_GETSTATUS:
+ case WDIOC_GETBOOTSTATUS:
+ return put_user(0, p);
+ }
+ return -ENOTTY;
+}
+
+/*
+ * Pat the watchdog whenever device is written to.
+ */
+static ssize_t at91_wdt_write(struct file *file, const char *data,
+ size_t len, loff_t *ppos)
+{
+ at91_wdt_reload(); /* pat the watchdog */
+ return len;
+}
+
+/* ......................................................................... */
+
+static const struct file_operations at91wdt_fops = {
+ .owner = THIS_MODULE,
+ .llseek = no_llseek,
+ .unlocked_ioctl = at91_wdt_ioctl,
+ .open = at91_wdt_open,
+ .release = at91_wdt_close,
+ .write = at91_wdt_write,
+};
+
+static struct miscdevice at91wdt_miscdev = {
+ .minor = WATCHDOG_MINOR,
+ .name = "watchdog",
+ .fops = &at91wdt_fops,
+};
+
+static int __init at91wdt_probe(struct platform_device *pdev)
+{
+ int res;
+
+ if (at91wdt_miscdev.parent)
+ return -EBUSY;
+ at91wdt_miscdev.parent = &pdev->dev;
+
+ res = misc_register(&at91wdt_miscdev);
+ if (res)
+ return res;
+
+ /* Set watchdog */
+ if (at91_wdt_settimeout(wdt_timeout) == -EINVAL) {
+ pr_info("at91sam9_wdt: timeout must be between 1 and %d.\n",
+ WDT_MAX_TIME);
+ return 0;
+ }
+
+ return 0;
+}
+
+static int __exit at91wdt_remove(struct platform_device *pdev)
+{
+ int res;
+
+ res = misc_deregister(&at91wdt_miscdev);
+ if (!res)
+ at91wdt_miscdev.parent = NULL;
+
+ return res;
+}
+
+#ifdef CONFIG_PM
+
+static int at91wdt_suspend(struct platform_device *pdev, pm_message_t message)
+{
+ return 0;
+}
+
+static int at91wdt_resume(struct platform_device *pdev)
+{
+ return 0;
+}
+
+#else
+#define at91wdt_suspend NULL
+#define at91wdt_resume NULL
+#endif
+
+static struct platform_driver at91wdt_driver = {
+ .remove = __exit_p(at91wdt_remove),
+ .suspend = at91wdt_suspend,
+ .resume = at91wdt_resume,
+ .driver = {
+ .name = "at91_wdt",
+ .owner = THIS_MODULE,
+ },
+};
+
+static int __init at91sam_wdt_init(void)
+{
+ return platform_driver_probe(&at91wdt_driver, at91wdt_probe);
+}
+
+static void __exit at91sam_wdt_exit(void)
+{
+ platform_driver_unregister(&at91wdt_driver);
+}
+
+module_init(at91sam_wdt_init);
+module_exit(at91sam_wdt_exit);
+
+MODULE_AUTHOR("Renaud CERRATO");
+MODULE_DESCRIPTION("Watchdog driver for Atmel AT91SAM9x processors");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
+MODULE_ALIAS("platform:at91_wdt");
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