[U-Boot-Users] Basic question during porting

[w.wegner at astro-kom.de]

Hi List,

I am trying to port u-boot to MCF5329/MCF5373 (target platform will have MCF5373, but I 
have a Cobra5329 for testing) and have some understanding problems.

I started from MCF5272/MCF5282 code (being somewhat confusing that both use very 
different style sometimes), and in include/configs/cobra5272.h there is the comment for 
CFG_SDRAM_BASE stating that this has to be "0". However, for the MCF53xx, I can not 
map the SDRAM to the address 0, I can only map it between 0x40000000 and 0x7FFFFFFF.

I could not yet see from where this limitation originates, but as it seems to be present in all 
architectures, I assume it is from u-boot itself. Can anybody give a short comment about 
this?

My understanding is that after start-up, (some?) code is copied from flash to internal RAM, 
then some peripherals or at least external memory is initialised, which can subsequently be 
used for further execution, so the problem should be "just" about linking and/or relocation, is 
this correct?

Thank you and best regards,
Wolfgang