[WATCHDOG] mv64x60_wdt: Support for WDIOC_SETTIMEOUT ioctl

Add the ability to modify the watchdog timer timeout interval.

Signed-off-by: Dale Farnsworth <dale@farnsworth.org>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

1 files changed, 31 insertions, 7 deletions

diff --git a/drivers/char/watchdog/mv64x60_wdt.c b/drivers/char/watchdog/mv64x60_wdt.c
index 420c7b82f4ca..e990e3af8be4 100644
--- a/drivers/char/watchdog/mv64x60_wdt.c
+++ b/drivers/char/watchdog/mv64x60_wdt.c
@@ -43,6 +43,7 @@ static unsigned long wdt_flags;
 static int wdt_status;
 static void __iomem *mv64x60_wdt_regs;
 static int mv64x60_wdt_timeout;
+static unsigned int bus_clk;
 
 static void mv64x60_wdt_reg_write(u32 val)
 {
@@ -82,6 +83,18 @@ static void mv64x60_wdt_handler_enable(void)
         }
 }
 
+static void mv64x60_wdt_set_timeout(int timeout)
+{
+        /* maximum bus cycle count is 0xFFFFFFFF */
+        if (timeout > 0xFFFFFFFF / bus_clk)
+                timeout = 0xFFFFFFFF / bus_clk;
+
+        mv64x60_wdt_timeout = timeout;
+        writel((timeout * bus_clk) >> 8,
+               mv64x60_wdt_regs + MV64x60_WDT_WDC_OFFSET);
+        mv64x60_wdt_service();
+}
+
 static int mv64x60_wdt_open(struct inode *inode, struct file *file)
 {
         if (test_and_set_bit(MV64x60_WDOG_FLAG_OPENED, &wdt_flags))
@@ -118,9 +131,11 @@ static ssize_t mv64x60_wdt_write(struct file *file, const char __user *data,
 static int mv64x60_wdt_ioctl(struct inode *inode, struct file *file,
                              unsigned int cmd, unsigned long arg)
 {
+        int timeout;
         void __user *argp = (void __user *)arg;
         static struct watchdog_info info = {
-                .options = WDIOF_KEEPALIVEPING,
+                .options =      WDIOF_SETTIMEOUT        |
+                                WDIOF_KEEPALIVEPING,
                 .firmware_version = 0,
                 .identity = "MV64x60 watchdog",
         };
@@ -150,7 +165,10 @@ static int mv64x60_wdt_ioctl(struct inode *inode, struct file *file,
                 break;
 
         case WDIOC_SETTIMEOUT:
-                return -EOPNOTSUPP;
+                if (get_user(timeout, (int __user *)argp))
+                        return -EFAULT;
+                mv64x60_wdt_set_timeout(timeout);
+                /* Fall through */
 
         case WDIOC_GETTIMEOUT:
                 if (put_user(mv64x60_wdt_timeout, (int __user *)argp))
@@ -182,15 +200,22 @@ static struct miscdevice mv64x60_wdt_miscdev = {
 static int __devinit mv64x60_wdt_probe(struct platform_device *dev)
 {
         struct mv64x60_wdt_pdata *pdata = dev->dev.platform_data;
-        int bus_clk = 133;
         struct resource *r;
+        int timeout = 10;
 
-        mv64x60_wdt_timeout = 10;
+        bus_clk = 133;                  /* in MHz */
         if (pdata) {
-                mv64x60_wdt_timeout = pdata->timeout;
+                timeout = pdata->timeout;
                 bus_clk = pdata->bus_clk;
         }
 
+        /* Since bus_clk is truncated MHz, actual frequency could be
+         * up to 1MHz higher.  Round up, since it's better to time out
+         * too late than too soon.
+         */
+        bus_clk++;
+        bus_clk *= 1000000;             /* convert to Hz */
+
         r = platform_get_resource(dev, IORESOURCE_MEM, 0);
         if (!r)
                 return -ENODEV;
@@ -199,8 +224,7 @@ static int __devinit mv64x60_wdt_probe(struct platform_device *dev)
         if (mv64x60_wdt_regs == NULL)
                 return -ENOMEM;
 
-        writel((mv64x60_wdt_timeout * (bus_clk * 1000000)) >> 8,
-               mv64x60_wdt_regs + MV64x60_WDT_WDC_OFFSET);
+        mv64x60_wdt_set_timeout(timeout);
 
         return misc_register(&mv64x60_wdt_miscdev);
 }