[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 <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>

Documentation/watchdog/watchdog-api.txt

···
 
 Not all watchdog drivers will support a pretimeout.
 
+Get the number of seconds before reboot:
+
+Some watchdog drivers have the ability to report the remaining time
+before the system will reboot. The WDIOC_GETTIMELEFT is the ioctl
+that returns the number of seconds before reboot.
+
+    ioctl(fd, WDIOC_GETTIMELEFT, &timeleft);
+    printf("The timeout was is %d seconds\n", timeleft);
+
 Environmental monitoring:
 
 All watchdog drivers are required return more information about the system,

drivers/char/watchdog/i8xx_tco.c

···
 	return 0;
 }
 
+static int tco_timer_get_timeleft (int *time_left)
+{
+	unsigned char val;
+
+	spin_lock(&tco_lock);
+
+	/* read the TCO Timer */
+	val = inb (TCO1_RLD);
+	val &= 0x3f;
+
+	spin_unlock(&tco_lock);
+
+	*time_left = (int)((val * 6) / 10);
+
+	return 0;
+}
+
 /*
  *	/dev/watchdog handling
  */
···
 {
 	int new_options, retval = -EINVAL;
 	int new_heartbeat;
+	int time_left;
 	void __user *argp = (void __user *)arg;
 	int __user *p = argp;
 	static struct watchdog_info ident = {
···
 				return -EFAULT;
 
 			if (tco_timer_set_heartbeat(new_heartbeat))
-			    return -EINVAL;
+				return -EINVAL;
 
 			tco_timer_keepalive ();
 			/* Fall */
···
 
 		case WDIOC_GETTIMEOUT:
 			return put_user(heartbeat, p);
+
+		case WDIOC_GETTIMELEFT:
+		{
+			if (tco_timer_get_timeleft(&time_left))
+				return -EINVAL;
+
+			return put_user(time_left, p);
+		}
 
 		default:
 			return -ENOIOCTLCMD;

drivers/char/watchdog/pcwd_pci.c

···
  */
 
 /*
- *	A bells and whistles driver is available from: 
+ *	A bells and whistles driver is available from:
  *	http://www.kernel.org/pub/linux/kernel/people/wim/pcwd/pcwd_pci/
  *
  *	More info available at http://www.berkprod.com/ or http://www.pcwatchdog.com/
···
 	return 0;
 }
 
+static int pcipcwd_get_timeleft(int *time_left)
+{
+	int msb;
+	int lsb;
+
+	/* Read the time that's left before rebooting */
+	/* Note: if the board is not yet armed then we will read 0xFFFF */
+	send_command(CMD_READ_WATCHDOG_TIMEOUT, &msb, &lsb);
+
+	*time_left = (msb << 8) + lsb;
+
+	if (debug >= VERBOSE)
+		printk(KERN_DEBUG PFX "Time left before next reboot: %d\n",
+		       *time_left);
+
+	return 0;
+}
+
 /*
  *	/dev/watchdog handling
  */
···
 
 		case WDIOC_GETTIMEOUT:
 			return put_user(heartbeat, p);
+
+		case WDIOC_GETTIMELEFT:
+		{
+			int time_left;
+
+			if (pcipcwd_get_timeleft(&time_left))
+				return -EFAULT;
+
+			return put_user(time_left, p);
+		}
 
 		default:
 			return -ENOIOCTLCMD;

drivers/char/watchdog/pcwd_usb.c

···
 	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
  */
···
 
 		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;

include/linux/watchdog.h

···
 #define	WDIOC_GETTIMEOUT        _IOR(WATCHDOG_IOCTL_BASE, 7, int)
 #define	WDIOC_SETPRETIMEOUT	_IOWR(WATCHDOG_IOCTL_BASE, 8, int)
 #define	WDIOC_GETPRETIMEOUT	_IOR(WATCHDOG_IOCTL_BASE, 9, int)
+#define	WDIOC_GETTIMELEFT	_IOR(WATCHDOG_IOCTL_BASE, 10, int)
 
 #define	WDIOF_UNKNOWN		-1	/* Unknown flag error */
 #define	WDIOS_UNKNOWN		-1	/* Unknown status error */
···
 #define	WDIOF_EXTERN2		0x0008	/* External relay 2 */
 #define	WDIOF_POWERUNDER	0x0010	/* Power bad/power fault */
 #define	WDIOF_CARDRESET		0x0020	/* Card previously reset the CPU */
-#define WDIOF_POWEROVER		0x0040	/* Power over voltage */
-#define WDIOF_SETTIMEOUT	0x0080  /* Set timeout (in seconds) */
-#define WDIOF_MAGICCLOSE	0x0100	/* Supports magic close char */
+#define	WDIOF_POWEROVER		0x0040	/* Power over voltage */
+#define	WDIOF_SETTIMEOUT	0x0080  /* Set timeout (in seconds) */
+#define	WDIOF_MAGICCLOSE	0x0100	/* Supports magic close char */
 #define	WDIOF_PRETIMEOUT	0x0200  /* Pretimeout (in seconds), get/set */
 #define	WDIOF_KEEPALIVEPING	0x8000	/* Keep alive ping reply */