3 files changed, 403 insertions, 0 deletions

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 1e48d4c45f86..713b1cef37d3 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -55,6 +55,11 @@ config SOFT_WATCHDOG
           To compile this driver as a module, choose M here: the
           module will be called softdog.
 
+config MAX63XX_WATCHDOG
+       tristate "Max63xx watchdog"
+       help
+         Support for memory mapped max63{69,70,71,72,73,74} watchdog timer.
+
 config WM831X_WATCHDOG
         tristate "WM831x watchdog"
         depends on MFD_WM831X
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index 2fd15947deb7..5e3cb95bb0e9 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -143,4 +143,5 @@ obj-$(CONFIG_WATCHDOG_CP1XXX)		+= cpwd.o
 # Architecture Independant
 obj-$(CONFIG_WM831X_WATCHDOG) += wm831x_wdt.o
 obj-$(CONFIG_WM8350_WATCHDOG) += wm8350_wdt.o
+obj-$(CONFIG_MAX63XX_WATCHDOG) += max63xx_wdt.o
 obj-$(CONFIG_SOFT_WATCHDOG) += softdog.o
diff --git a/drivers/watchdog/max63xx_wdt.c b/drivers/watchdog/max63xx_wdt.c
new file mode 100644
index 000000000000..6eb91d757604
--- /dev/null
+++ b/drivers/watchdog/max63xx_wdt.c
@@ -0,0 +1,397 @@
+/*
+ * drivers/char/watchdog/max63xx_wdt.c
+ *
+ * Driver for max63{69,70,71,72,73,74} watchdog timers
+ *
+ * Copyright (C) 2009 Marc Zyngier <maz@misterjones.org>
+ *
+ * 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.
+ *
+ * This driver assumes the watchdog pins are memory mapped (as it is
+ * the case for the Arcom Zeus). Should it be connected over GPIOs or
+ * another interface, some abstraction will have to be introduced.
+ */
+
+#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 <linux/platform_device.h>
+#include <linux/spinlock.h>
+#include <linux/uaccess.h>
+#include <linux/io.h>
+#include <linux/device.h>
+
+#define DEFAULT_HEARTBEAT 60
+#define MAX_HEARTBEAT     60
+
+static int heartbeat = DEFAULT_HEARTBEAT;
+static int nowayout  = WATCHDOG_NOWAYOUT;
+
+/*
+ * Memory mapping: a single byte, 3 first lower bits to select bit 3
+ * to ping the watchdog.
+ */
+#define MAX6369_WDSET   (7 << 0)
+#define MAX6369_WDI     (1 << 3)
+
+static DEFINE_SPINLOCK(io_lock);
+
+static unsigned long wdt_status;
+#define WDT_IN_USE      0
+#define WDT_RUNNING     1
+#define WDT_OK_TO_CLOSE 2
+
+static int nodelay;
+static struct resource  *wdt_mem;
+static void __iomem     *wdt_base;
+static struct platform_device *max63xx_pdev;
+
+/*
+ * The timeout values used are actually the absolute minimum the chip
+ * offers. Typical values on my board are slightly over twice as long
+ * (10s setting ends up with a 25s timeout), and can be up to 3 times
+ * the nominal setting (according to the datasheet). So please take
+ * these values with a grain of salt. Same goes for the initial delay
+ * "feature". Only max6373/74 have a few settings without this initial
+ * delay (selected with the "nodelay" parameter).
+ *
+ * I also decided to remove from the tables any timeout smaller than a
+ * second, as it looked completly overkill...
+ */
+
+/* Timeouts in second */
+struct max63xx_timeout {
+        u8 wdset;
+        u8 tdelay;
+        u8 twd;
+};
+
+static struct max63xx_timeout max6369_table[] = {
+        { 5,  1,  1 },
+        { 6, 10, 10 },
+        { 7, 60, 60 },
+        { },
+};
+
+static struct max63xx_timeout max6371_table[] = {
+        { 6, 60,  3 },
+        { 7, 60, 60 },
+        { },
+};
+
+static struct max63xx_timeout max6373_table[] = {
+        { 2, 60,  1 },
+        { 5,  0,  1 },
+        { 1,  3,  3 },
+        { 7, 60, 10 },
+        { 6,  0, 10 },
+        { },
+};
+
+static struct max63xx_timeout *current_timeout;
+
+static struct max63xx_timeout *
+max63xx_select_timeout(struct max63xx_timeout *table, int value)
+{
+        while (table->twd) {
+                if (value <= table->twd) {
+                        if (nodelay && table->tdelay == 0)
+                                return table;
+
+                        if (!nodelay)
+                                return table;
+                }
+
+                table++;
+        }
+
+        return NULL;
+}
+
+static void max63xx_wdt_ping(void)
+{
+        u8 val;
+
+        spin_lock(&io_lock);
+
+        val = __raw_readb(wdt_base);
+
+        __raw_writeb(val | MAX6369_WDI, wdt_base);
+        __raw_writeb(val & ~MAX6369_WDI, wdt_base);
+
+        spin_unlock(&io_lock);
+}
+
+static void max63xx_wdt_enable(struct max63xx_timeout *entry)
+{
+        u8 val;
+
+        if (test_and_set_bit(WDT_RUNNING, &wdt_status))
+                return;
+
+        spin_lock(&io_lock);
+
+        val = __raw_readb(wdt_base);
+        val &= ~MAX6369_WDSET;
+        val |= entry->wdset;
+        __raw_writeb(val, wdt_base);
+
+        spin_unlock(&io_lock);
+
+        /* check for a edge triggered startup */
+        if (entry->tdelay == 0)
+                max63xx_wdt_ping();
+}
+
+static void max63xx_wdt_disable(void)
+{
+        spin_lock(&io_lock);
+
+        __raw_writeb(3, wdt_base);
+
+        spin_unlock(&io_lock);
+
+        clear_bit(WDT_RUNNING, &wdt_status);
+}
+
+static int max63xx_wdt_open(struct inode *inode, struct file *file)
+{
+        if (test_and_set_bit(WDT_IN_USE, &wdt_status))
+                return -EBUSY;
+
+        max63xx_wdt_enable(current_timeout);
+        clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
+
+        return nonseekable_open(inode, file);
+}
+
+static ssize_t max63xx_wdt_write(struct file *file, const char *data,