[WATCHDOG] add WDIOC_GETTIMELEFT ioctl

Some watchdog drivers have the ability to report the remaining time
before the system will reboot. With the WDIOC_GETTIMELEFT ioctl
you can now read the time left before the watchdog would reboot
your system.

The following drivers support this new IOCTL:
i8xx_tco.c, pcwd_pci.c and pcwd_usb.c .

Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Signed-off-by: Andrew Morton <akpm@osdl.org>

1 files changed, 23 insertions, 0 deletions

diff --git a/drivers/char/watchdog/pcwd_usb.c b/drivers/char/watchdog/pcwd_usb.c
index 3fdfda9324fae4..0d072bed501dfd 100644
--- a/drivers/char/watchdog/pcwd_usb.c
+++ b/drivers/char/watchdog/pcwd_usb.c
@@ -317,6 +317,19 @@ static int usb_pcwd_get_temperature(struct usb_pcwd_private *usb_pcwd, int *temp
 	return 0;
 }
 
+static int usb_pcwd_get_timeleft(struct usb_pcwd_private *usb_pcwd, int *time_left)
+{
+	unsigned char msb, lsb;
+
+	/* Read the time that's left before rebooting */
+	/* Note: if the board is not yet armed then we will read 0xFFFF */
+	usb_pcwd_send_command(usb_pcwd, CMD_READ_WATCHDOG_TIMEOUT, &msb, &lsb);
+
+	*time_left = (msb << 8) + lsb;
+
+	return 0;
+}
+
 /*
  *	/dev/watchdog handling
  */
@@ -422,6 +435,16 @@ static int usb_pcwd_ioctl(struct inode *inode, struct file *file,
 		case WDIOC_GETTIMEOUT:
 			return put_user(heartbeat, p);
 
+		case WDIOC_GETTIMELEFT:
+		{
+			int time_left;
+
+			if (usb_pcwd_get_timeleft(usb_pcwd_device, &time_left))
+				return -EFAULT;
+
+			return put_user(time_left, p);
+		}
+
 		default:
 			return -ENOIOCTLCMD;
 	}