[U-Boot-Users] PPC440Epx Sequoia Flash-based size limitation?

[Niklaus Giger <niklausgiger@gmx.ch>]

Hi Dave

Dave Littell wrote:
> Hi all,
> 
> I'm working on an AMCC PPC440EPx platform that is similar to the AMCC
We have also a PPC440EPx based board (HCU5, in the u-boot tree).
> Sequoia under U-Boot 1.3.1.  I've copied the Sequoia board and
> configuration as a starting point, but I've run into a problem with the
> size of the flash-based portion of U-Boot.  I've added code to
> initdram() that results in the addition of 3-4 dozen assembly
> instructions.  Now the board hangs after a very few tftp (or even ping)
> commands.  However, if I remove the code I added, there's no problem
> with tftp, etc.  I've narrowed it down to the point where I can make the
> difference between a working and non-working load by adding just a few
> instructions to initdram().  Some boundary or limit is being crossed
> somewhere...

Recently, (the last few weeks) we did run in a similar problem that
loading the vxWorks image hangs in the middle of the tftp transfer.
Some boards have it never, newer ones more often and some have it more 
or less often depending on the physical locatian, e.g. they show the
behaviour at my workplace but not at the workplace of my co-worker.
Sometimes it has this behaviour just at the beginning and after a few
minutes it loads the whole image without problem.

I am investigating the problem. It seems that sometimes I get a
IVOR1 (Machine check) -exception. But unfortunatly I do not have at 
the moment a  setup where I can easily reproduce the problem.

This may be a problem which may or may not be related to yours.

Also be warned that the PPC440EPx is a very powerful CPU where a 
lot of parallelisme exists. We did run into subtle, hard to find
problems because the CPU did reorder read/write accesses to
different addreses. Therefore if you access somewhere memory based
CPLD/MACH or other registers always use the in_/out_<xx> macros.

Best regards

Niklaus