So it's just an offset to VDDC? I'd like to keep VDDCI fixed, while still having VDDC change according to the dpm state.
No it's an offset to VDDCI/AUX, they both have seperate offsets in the rom. In 90% of the cases you won't find VDDCI offset, so you can add it
8D = VDDC , 8E = VDDCI/AUX or MVDDC
So where would you add it? I only recently found ATOM BIOS reader, and still haven't figured out the dynamic voltage control for Tonga.
I know when Voltage Table2 in PowerPlayInfo has values that start with FF, that indicates dynamic voltage control. Otherwise it's just the voltage in mV for that DPM state (i.e. 84 03 = 0x384 = 900mV).
For the values that start with FF (i.e. 0xFF08), I think the 08 is an index to another table that contains values for calculating the dynamic voltage. But I haven't found where that table is in the ROM.