[coreboot] Via EPIA-N(L) C3/CN400 Support - Help Wanted

[Jon Harrison]

Hi Guys,

I'm currently working on porting coreboot to the Via EPIA-N(L) i.e. 
C3/CN400/VT8237R/Winbond SuperIO.

I'm a fairly competent embedded systems designer/coder, and I'm aiming 
to get to the point where I can use the EPIA to run a small linux kernel 
and custom service from flash to act as a data logger from a custom 
perpheral to a SATA disk.

I'm not NDAd with Via (spent months trying to do this and gave up  after 
getting the run around for so long)  but have aquired some data on the 
CN400 that has allowed me to get this far. I don't have the BIOS Porting 
Guide, which suspect would be quite illuminating, if there is anyone out 
there who does have this and could review/correct my code for errors I'd 
appreciate it.

I've got to the point where I have flashrom programming the board, I 
have a working build environment for V2 which is running the early romcc 
compiled code and seems to have done the CN400 meminit stuff OK, near as 
I can tell I am able to access SDRAM OK from romcc code (the early 
serial stuff is up and running OK, and i can get debug out that way), 
but I'm getting strange things happening when jumping to copy_and_run_core.

I think that the basic problem is a linking/location problem.

Options.lb doesn't seem to let me turn on print_spew in the gcc code but 
works OK in the romcc code, and the .map file looks suspicious to me 
with loads of constants all defined at the same location.

If anyone is interested in helping me then I'd appreciate it.

I'm happy to do the leg work if someone can give me a steer into how all 
of the different ROM_SIZE, ROM_SECTION_SIZE PAYLOAD_SIZE, FALLBACK_SIZE 
etc. etc. relate to the linking and location of code. I'm finding this a 
bit impenetrable at the moment.

Alternatively if anyone could suggest a good host debug/emulation 
environment to workout what's going on.......

Thanks,
Jon