[WATCHDOG] Orion: add hardware watchdog support

This patch allows the use of the hardware watchdog in the
Marvell Orion series of ARM SoCs.

Signed-off-by: Sylver Bruneau <sylver.bruneau@googlemail.com>
Signed-off-by: Lennert Buytenhek <buytenh@marvell.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

3 files changed, 241 insertions, 0 deletions

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 6a711eb6998b..1a22fe782a27 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -224,6 +224,15 @@ config DAVINCI_WATCHDOG
           NOTE: once enabled, this timer cannot be disabled.
           Say N if you are unsure.
 
+config ORION5X_WATCHDOG
+        tristate "Orion5x watchdog"
+        depends on ARCH_ORION5X
+        help
+          Say Y here if to include support for the watchdog timer
+          in the Orion5x ARM SoCs.
+          To compile this driver as a module, choose M here: the
+          module will be called orion5x_wdt.
+
 # ARM26 Architecture
 
 # AVR32 Architecture
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index f896d6f666bc..d604430ffeb8 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -40,6 +40,7 @@ obj-$(CONFIG_EP93XX_WATCHDOG) += ep93xx_wdt.o
 obj-$(CONFIG_PNX4008_WATCHDOG) += pnx4008_wdt.o
 obj-$(CONFIG_IOP_WATCHDOG) += iop_wdt.o
 obj-$(CONFIG_DAVINCI_WATCHDOG) += davinci_wdt.o
+obj-$(CONFIG_ORION5X_WATCHDOG) += orion5x_wdt.o
 
 # ARM26 Architecture
 
diff --git a/drivers/watchdog/orion5x_wdt.c b/drivers/watchdog/orion5x_wdt.c
new file mode 100644
index 000000000000..144776314989
--- /dev/null
+++ b/drivers/watchdog/orion5x_wdt.c
@@ -0,0 +1,231 @@
+/*
+ * drivers/watchdog/orion5x_wdt.c
+ *
+ * Watchdog driver for Orion5x processors
+ *
+ * Author: Sylver Bruneau <sylver.bruneau@googlemail.com>
+ *
+ * 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/uaccess.h>
+#include <linux/io.h>
+
+/*
+ * Watchdog timer block registers.
+ */
+#define TIMER_CTRL              (TIMER_VIRT_BASE + 0x0000)
+#define  WDT_EN                 0x0010
+#define WDT_VAL                 (TIMER_VIRT_BASE + 0x0024)
+
+#define WDT_MAX_DURATION        (0xffffffff / ORION5X_TCLK)
+#define WDT_IN_USE              0
+#define WDT_OK_TO_CLOSE         1
+
+static int nowayout = WATCHDOG_NOWAYOUT;
+static int heartbeat =  WDT_MAX_DURATION;       /* (seconds) */
+static unsigned long wdt_status;
+
+static void wdt_enable(void)
+{
+        u32 reg;
+
+        /* Set watchdog duration */
+        writel(ORION5X_TCLK * heartbeat, WDT_VAL);
+
+        /* Clear watchdog timer interrupt */
+        reg = readl(BRIDGE_CAUSE);
+        reg &= ~WDT_INT_REQ;
+        writel(reg, BRIDGE_CAUSE);
+
+        /* Enable watchdog timer */
+        reg = readl(TIMER_CTRL);
+        reg |= WDT_EN;
+        writel(reg, TIMER_CTRL);
+
+        /* Enable reset on watchdog */
+        reg = readl(CPU_RESET_MASK);
+        reg |= WDT_RESET;
+        writel(reg, CPU_RESET_MASK);
+}
+
+static void wdt_disable(void)
+{
+        u32 reg;
+
+        /* Disable reset on watchdog */
+        reg = readl(CPU_RESET_MASK);
+        reg &= ~WDT_RESET;
+        writel(reg, CPU_RESET_MASK);
+
+        /* Disable watchdog timer */
+        reg = readl(TIMER_CTRL);
+        reg &= ~WDT_EN;
+        writel(reg, TIMER_CTRL);
+}
+
+static int orion5x_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 int orion5x_wdt_get_timeleft(int *time_left)
+{
+        *time_left = readl(WDT_VAL) / ORION5X_TCLK;
+        return 0;
+}
+
+static ssize_t orion5x_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_MAGICCLOSE | WDIOF_SETTIMEOUT |
+                          WDIOF_KEEPALIVEPING,
+        .identity       = "Orion5x Watchdog",
+};
+
+
+static long orion5x_wdt_ioctl(struct file *file, unsigned int cmd,
+                                unsigned long arg)
+{
+        int ret = -ENOTTY;
+        int time;
+
+        switch (cmd) {
+        case WDIOC_GETSUPPORT:
+                ret = copy_to_user((struct watchdog_info *)arg, &ident,
+                                   sizeof(ident)) ? -EFAULT : 0;
+                break;
+
+        case WDIOC_GETSTATUS:
+        case WDIOC_GETBOOTSTATUS:
+                ret = put_user(0, (int *)arg);
+                break;
+
+        case WDIOC_KEEPALIVE:
+                wdt_enable();
+                ret = 0;
+                break;
+
+        case WDIOC_SETTIMEOUT:
+                ret = get_user(time, (int *)arg);
+                if (ret)
+                        break;
+
+                if (time <= 0 || time > WDT_MAX_DURATION) {
+                        ret = -EINVAL;
+                        break;
+                }
+                heartbeat = time;
+                wdt_enable();
+                /* Fall through */
+
+        case WDIOC_GETTIMEOUT:
+                ret = put_user(heartbeat, (int *)arg);
+                break;
+
+        case WDIOC_GETTIMELEFT:
+                if (orion5x_wdt_get_timeleft(&time)) {
+                        ret = -EINVAL;
+                        break;
+                }
+                ret = put_user(time, (int *)arg);
+                break;
+        }
+        return ret;
+}
+
+static int orion5x_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 unexpectedly - "
+                                        "timer will not stop\n");
+        clear_bit(WDT_IN_USE, &wdt_status);
+        clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
+
+        return 0;
+}
+
+
+static const struct file_operations orion5x_wdt_fops = {
+        .owner          = THIS_MODULE,
+        .llseek         = no_llseek,
+        .write          = orion5x_wdt_write,
+        .unlocked_ioctl = orion5x_wdt_ioctl,
+        .open           = orion5x_wdt_open,
+        .release        = orion5x_wdt_release,
+};
+
+static struct miscdevice orion5x_wdt_miscdev = {
+        .minor          = WATCHDOG_MINOR,
+        .name           = "watchdog",
+        .fops           = &orion5x_wdt_fops,
+};
+
+static int __init orion5x_wdt_init(void)
+{
+        int ret;
+
+        ret = misc_register(&orion5x_wdt_miscdev);
+        if (ret == 0)
+                printk("Orion5x Watchdog Timer: heartbeat %d sec\n",
+                                                                heartbeat);
+
+        return ret;
+}
+
+static void __exit orion5x_wdt_exit(void)
+{
+        misc_deregister(&orion5x_wdt_miscdev);
+}
+
+module_init(orion5x_wdt_init);
+module_exit(orion5x_wdt_exit);
+
+MODULE_AUTHOR("Sylver Bruneau <sylver.bruneau@googlemail.com>");
+MODULE_DESCRIPTION("Orion5x Processor Watchdog");
+
+module_param(heartbeat, int, 0);
+MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds (default is "
+                                        __MODULE_STRING(WDT_MAX_DURATION) ")");
+
+module_param(nowayout, int, 0);
+MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
+
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);