[U-Boot] ppc44x - watchdog timers reboots during the image loading

[ame <ayman@phx1-ss-2-lb.cnet.com>]

On my 460ex board, i've tried to add CONFIG_WATCHDOG to the config and it appears to
work until the board tries to boot.  At that point I can count down about 10 seconds
and the reboot happens.  The 10s correlates with what I think the watchdog is being
set to.  I've inserted some WATCHDOG_RESET() invocations wrapping memmove_wd (which 
admittedly should not be needed), but it does not have an effect.  The last message
I see is ...

   Verifying Checksum ... OK
## Flattened Device Tree blob at ff3e0000
   Booting using the fdt blob at 0xff3e0000
   Uncompressing Kernel Image ... OK
   Loading Device Tree to 007fa000, end 007ffd2f ... OK
   Loading Ramdisk to 1ec58000, end 1efffc0c ... OK

Then it instantly resets.  If I remove CONFIG_WATCHDOG the board works and boots
correctly.  My u-boot is circa early 2009.  From looking at the current u-boot it
does not have the tcr and tsr registers "converted to uppercase", so I don't think
it builds yet.  I've verified the addresses of the spr and they look correct.

Any thoughts or help are appreciated.  I did notice the comments in cpu-init.c 
that my tcr is setup with 0xF0000000, I *think* this is actually 10s on a 800MHz
board.  Not sure where the 2.684 numbers originates as stated in the comments.
I also changed the acknowledge of the watchdog to the following, though neither my
changes nor the original have any effect.  I've also verified that the code is 
getting included and built.   Not sure what to try next.

void reset_4xx_watchdog(void)
{
	/*
	 * Clear TSR(WIS) bit
	 */
	mtspr(tsr, 0xC0000000);
}
#endif	/* CONFIG_WATCHDOG */