[coreboot] ask for ideas and suggestions about CBFS support on ARM

Joseph Smith joe at settoplinux.org
Sun Apr 10 18:10:27 CEST 2011

On 04/10/2011 08:49 AM, Hamo wrote:
> Dear lists,
> I have be studying CBFS filesystem these days. Since coreboot only
> supports IA32 architecture now, the CBFS has hard-coded boot address
> and all the boot-related code and master header are located at around
> 0xFFFFFFF0. But as ARM read their first instruction at 0x0, we need
> change the CBFS filesystem but not destroy IA32 support. When porting
> to ARM, how should the rom be organized? I have 2 ideas:
> 1. Totally rewrite the CBFS structure on ARM according to that one on
> IA32 to meet the requirement of ARM architecture, including move the
> reset code and bootblock to the start of ROM(at address 0x0) and put
> all the other components follow them. In this way, we should rewrite
> the CBFStool and add a new option to CBFStool to tell it the
> architecture we are using.
> 2. Use the same structure on IA32 architecture but set the master
> header's offset to other value than 0x0 so that we can put boot code
> at the start of rom.
> Which one should I take or Do we have any better choice?
> Hope for your help.
How about spitting up the code using pre-processing directives? One for 
arm and one for IA32? Just a thought.

Joseph Smith

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