Hi Lenny,
There is a support for Carrizo processor using CarrizoPI AGESA blob. If I am not mistaken the CPUID of this processor will be 660F01, so related southbridge and northbridge support is there under src/nortbridge/amd/pi/00660F01 and src/soutbridge/amd/pi/00660F01. But what I am concerned about is that Opteron is a server processor, while the AGESA in coreboot was designed to work with mobile processor lines (Merlin Falcon - Embedded R-series). I think the hardware initialization will lack certain things for server SKU.
AFUWIN will probably expect some AMI format of the BIOS image, so I suspect it may not work.
Sincerely,