[U-Boot] On simple standalone applications
Alessio Sangalli
alesan at manoweb.com
Sun Aug 31 09:50:05 CEST 2008
Wolfgang Denk wrote:
> Are you sure about this? Normally ARM systems have flash memory (or
> some other ROM) mapped at 0, because this is where execution starts
> out of reset.
Yes I am. On this system (at least as it is now) U-boot is executed from
memory when DDR has already been initialized. So yes, I confirm DDR is
mapped from 0x00000000 to 0x3fffffff but I only have 64MB so the end of
physical RAM is 0x03ffffff.
>> First problem: I can compile U-boot with ELDK 4.1 but if I enter the
>> "examples" directory and issue a make:
>
> Who says you should do that? The examples are automatically built when
> running "make all" (or just "make") in the top level directory.
Sorry my fault.
>> I do not have RAM at that location! Shall I modify the Makefile for this?
>
> Yes, you have to adjust the link address to your actual memory map.
Well now it is somewhat clearer and I think I understand. I will do some
experiments on the target on Tuesday, after labor's day of course :)
> It's not only gly, but also error-prone. You should not use plain
> pointer accesses to read or write to registers, but the correct
> accessor functions/macros ({in,out}[bwl]).
Uh... are those defined for U-boot as well? Thanks.
bye!
as
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