[U-Boot-Users] CONFIG_BOOTBINFUNC for AT91RM9200
Steven Scholz
steven.scholz at imc-berlin.de
Tue Nov 23 17:51:12 CET 2004
Wolfgang Denk wrote:
> In message <41A35A7E.1020605 at imc-berlin.de> you wrote:
>
>>is there a standard way in U-Boot to prevent to the startup code from relocating
>>into RAM?
>
> No. U-Boot will always relocate itself to RAM. Well, nearly always -
> in any halfway sane implementation.
>
>
>>I know that arm920t figures out the currebt address. compares it to _TEXT_BASE
>>and decides wether to relocate or not.
>>
>>relocate: /* relocate U-Boot to RAM */
>> adr r0, _start /* r0 <- current position of code */
>> ldr r1, _TEXT_BASE /* test if we run from flash or RAM */
>> cmp r0, r1 /* don't reloc during debug */
>
>
> I wish that code was never written.
Why is that so bad? It makes it possible to debug U-Boot with just loading the
image into RAM using BDI2000.
> All CPUs always relocate the code to RAM. This is the general case.
> Anything else is not supported.
But how would you debug U-Boot?
I though the common way is to disabled relocation and memsetup, load that U-Boot
image with an BDI2000 into RAM and execute it - skipping the init code...
--
Steven
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