[U-Boot-Users] PXA (XScale) memory layout

Anders Larsen alarsen at rea.de
Thu Sep 11 17:38:48 CEST 2003

Robert Schwebel <robert at schwebel.de> schreibt:
>The boards I have ported use the memory layout which is documented in
>the README. Unfortunately, due to historical reasons the old ARMboot
>code uses another scheme and nobody had the time to fix this "the right

Hi Robert,

even the relatively new (added sometime after 0.4.0) ARM925T code uses
the old scheme...

I fully agree, though, that the documented scheme is better (having the
stack grow downwards towards the code can lead to interesting side-
effects ;-)
>> It seems to be causing a certain amount of grief (and dirty workarounds,
>> like e.g. in board/wepep250/wepep250.c lines 43..53) that
>> cpu/pxa/start.S places stack (and heap) below the code instead of above.
>My -ptx patches have a hack for this, but I agree with Wolfgang that
>somebody should fix it correctly instead of applying workarounds...

AFAICT, cpu/pxa/cpu.c just needs to set

  _armboot_real_end = TEXT_BASE - CFG_MALLOC_LEN;

in cpu_init(), then no further "würgarounds" are needed for PXA boards.

After that, it's not too much work to fix the other ARMs, since the
entire magic plays in cpu/.../

Or did I miss something?


More information about the U-Boot mailing list