On Wednesday 02 July 2008, Yi-Neng Lin wrote:
This arises another question. Assume that both configurations (CPU and SDRAM) are obtained from the EEPROM, how can C program/function be adopted to use these parameters before CPU/memory is initiated? C programs/functions need memory space to setup the stacks, which means CPU/memory initialization should be done (via assembly) before any C programs/functions can be used.
All this is already taken care of. U-Boot uses a small area for initial RAM. Sometimes in D-cache, sometimes in onboard SRAM (SoC). IIRC, the 405EP has OCM, so this could be used here. You just need to configure this correctly in your board config file. Again I suggest you take a look at the zeus board as an example.
Best regards, Stefan
===================================================================== DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: +49-8142-66989-0 Fax: +49-8142-66989-80 Email: office@denx.de =====================================================================