[U-Boot] AMCC 405EX Trap

[Jonathan Haws]

> On Thursday 30 April 2009, Jonathan Haws wrote:
> > I am certain that it is a hardware failure that is causing the machine
> > check because I can use the exact same binary on another (identical)
> board
> > and have it boot just fine.  That tells me that all the EBC and SDRAM
> > settings are correct;
> 
> From my experience you can't be sure that SDRAM setting are "currect" at
> this
> stage.

Would that be the case on our other 6 boards then?  We have 6 boards that are up and running with the exact same U-Boot binary file.  If there was a problem with the SDRAM settings on one board, would not the other board show the same symptoms?  That is the reason why I have not dug deeper into the SDRAM initialization.  However, I will take your advice and do so, because if there is a problem there, then the other boards may be experiencing problems, just not to the extent that this one is.

> 
> > and that I am using the right addresses and chip
> > selects for the data cache.
> >
> > Currently I am leaning toward an SDRAM problem because I get about a 20
> > second pause when U-Boot tries to relocate to RAM.
> 
> Yes, I'm pretty sure that you have some SDRAM related problems. Either
> configuration is non-optimal, or even (perhaps more unlikely) a hardware
> problem. I suggest that you re-check the DDR2 autocalibration (method A &
> B).
> 

Thanks for confirming my initial hunch - problem lies in SDRAM.  I will let you know what I find - whether it is a hardware or software problem.

One thing I may mention is that we had the SDRAM chips re-balled before they were mounted on the board.  Maybe something went wrong during that process on these chips on the problem board - who knows.

Anyway, once I get this resolved I will post the solution.

Thanks all!

Jonathan