[U-Boot-Users] Memory Banks & Flash Mapping

Josef Angermeier Josef.Angermeier at informatik.stud.uni-erlangen.de
Fri Feb 17 10:20:49 CET 2006


Hello

> > Further, i am now facing the problem, that my BR1 SDRAM-memory bank gets
> > changed correctly at u-boot runtime, but the BR0-flash-memory-bank keeps
> > its PRELIM-value when reaching the command shell. 

> Misconfigured system?

from README:

"Because of the reset configuration for CS0# this is a mirror of the
onboard Flash memory.  To be able to re-map memory U-Boot then jumps to
its link address."

I don't get the second sentence. Flash is executed near the beginning of
address space, exactly where the SDRAM shall get mapped. How is this
possible ? 

As far as i understand my (working) u-boot code, relocation just works
for my MPC875 board just because SDRAM is 64MB and Flash is 16MB in
size. So when both are mapped to 0x0 just the first 16MB overlap and
u-boot can be successfully copied at the 64th MB and executed there. But
how could it be done if i just got 16MB of SDRAM ?

> > One last question: I am porting u-boot to a not yet very popular
> > developer board with a MPC875. Shall i add my changes although to your
> > CVS repository ?

> CVS is dead. We use git now.

My concern was, if you are interested in my extensions.

> Best regards,

> Wolfgang Denk

Thanks again Wolfgang

Josef Angermeier





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