[U-Boot] Virtex 4 with XMD

[Rommel Custodio]

Rommel Custodio <sessyargc+uboot <at> gmail.com> writes:

> 
> Dear Frank,
> 
> >Frank Lombardo <fastfrank <at> gmail.com> writes:
> 
> > So, that leaves me with the following questions:
> > 1) Is the lack of flash memory causing THIS problem?
> > 2) Am I missing some config items?
> > 3) Does anybody have any advice on how I can debug this?
> 
> I'm on an ML507 and I use the default configuration for u-boot. So try the 
> defaults (SYS_TEXT_BASE and RESET_VECTOR_ADDRESS) first.

Sorry, the defaults won't work in your case. I didn't notice that you only have 
64Mb earlier.

> 
> I used the instructions here when I used XMD:
> <http://wiki.xilinx.com/powerpc-linux>
> Just change the kernel ELF file for the u-boot ELF file.
> 
> There are two targets for all the u-boot supported Xilinx boards in the 
> boards.cfg. The one for Flash has "_flash" so it's very easy to differentiate.

After successfully downloading the u-boot ELF to RAM, dump the first few words 
at the load address (SYS_TEXT_BASE). It should be a jump to _start. You could 
also disassemble your u-boot.

I built xilinx-ppc405-generic as a test and the first instruction is not a jump 
to _start. In ppc440 RAM boot (ie for use in XMD) the first instruction is a 
jump to _start_440 as this emulates going through the reset vector. IMHO, at the 
moment, it seems 405 is broken for RAM boot.


I hope my understanding is correct. Would like to hear from the PowerPC guys in 
the list.

All the best,
Rommel