Only disable the MPC83xx watchdog if its enabled out of reset.

If its disabled out of reset SW can later enable it if so desired
Patch by Kumar Gala, 11 Jan 2006

CHANGELOG

@@ -2,6 +2,10 @@
 Changes since U-Boot 1.1.4:
 ======================================================================
 
+* Only disable the MPC83xx watchdog if its enabled out of reset.
+  If its disabled out of reset SW can later enable it if so desired
+  Patch by Kumar Gala, 11 Jan 2006
+
 * Allow config of GPIO direction & data registers at boot on 83xx
   Patch by Kumar Gala, 11 Jan 2006
 

cpu/mpc83xx/start.S

@@ -426,8 +426,14 @@ init_e300_core: /* time t 10 */
 #else
 	/* Disable Wathcdog  */
 	/*-------------------*/
+	lwz r4, SWCRR(r3)
+	/* Check to see if its enabled for disabling
+	   once disabled by SW you can't re-enable */
+	andi. r4, r4, 0x4
+	beq 1f
 	xor r4, r4, r4
 	stw r4, SWCRR(r3)
+1:
 #endif /* CONFIG_WATCHDOG */
 
 	/* Initialize the Hardware Implementation-dependent Registers */