[U-Boot-Users] Software watchdog on mpc8247

[Jerry Van Baren <gerald.vanbaren@smiths-aerospace.com>]

Mike Rapoport wrote:
> On 8/25/05, Jerry Van Baren <gerald.vanbaren@smiths-aerospace.com> wrote:
> 
>>What did you set the SYPCR to (actual values, preferably from a
>>disassembly/dump)?  
> 
> 
> Here's the output of "objdump -dS u-boot" :
> /* Initialise the SYPCR early, and reset the watchdog (if req)  */
> /*--------------------------------------------------------------*/
> 
>         lis     r3, (CFG_IMMR+IM_REGBASE)@h
> fff03198:       3c 60 f0 01     lis     r3,-4095
> #if !defined(CONFIG_COGENT)
>         lis     r4, CFG_SYPCR at h
> fff0319c:       3c 80 ff ff     lis     r4,-1
>         ori     r4, r4, CFG_SYPCR at l
> fff031a0:       60 84 ff c3     ori     r4,r4,65479
>         stw     r4, IM_SYPCR at l(r3)
> fff031a4:       90 83 00 04     stw     r4,4(r3)
> #endif /* !CONFIG_COGENT */
> #if defined(CONFIG_WATCHDOG)
>         li      r4, 21868               /* = 0x556c */
>         sth     r4, IM_SWSR at l(r3)
>         li      r4, -21959              /* = 0xaa39 */
>         sth     r4, IM_SWSR at l(r3)
> 
> Actual SYPCR setting is 0xFFFFFFC7
> I verified that this code is executed.
> 
> I've tried to add WATCHDOG_RESET() call in board_init_f just before
> the initialization sequence was run, but it didn't change anything.
> 
>>What is your bus clock?  
> 
> 66MHz
> 
>>What do you figure your  timeout to be?  
> 
> 2 sec
> 
>>Do you write to the SYPCR only once to set up the WDT
>>(only the first write to the SYPCR "works").
> 
> Yes

Pointing out the obvious... looking at the disassembly, it isn't 
enabling the watchdog (SWE).  I'm guessing that you disassembled code 
where you had the watchdog disabled?

I see you have PBME and LBME enabled (I'm looking at an 8260 manual, 
assuming the 8247 is the same - feel free to correct me :-).  Do you 
have a 60x bus and a local bus?  Is it possible you are having an 
inadvertant bus error?  This wouldn't explain why it only happens when 
you enable the WDT, however.  Puzzling.

gvb