The MPC106, codenamed "Grackle", is a PCI bridge/memory controller. Its predecessor was the MPC105, codenamed "Eagle". It replaced an Apple-made host bridge codenamed "Bandit", part number 343S1125.
Unlike the CPU, which generally runs in big-endian mode, the Grackle runs in little-endian mode in compliance with the PCI standard. This usually means that to get the result in the correct endian, the PowerPC must load and store byte-reversed inputs and results.
CONFIG_ADDR can be found at any address in the range 0xFEC00000–0xFEDFFFFF, while CONFIG_DAT can be found at any address in the range 0xFEE00000–0xFEEFFFFF. The device trees also establish 0xFEF00000 as the 8259 interrupt acknowledgement register.
With minor additions to source code, dingusppc can add a known PCI device to any device number between @1 and @1f except for @10 and @12. A nvramrc patch can make Open Firmware probe the other device numbers. An OS might be able to probe these other device numbers even if they are not probed by Open Firmware.
A better approach may be to attach a PCI bridge to one of the supported slots. Then additional devices can be attached to the PCI bridge. For a PCI bridge, Open Firmware will probe device numbers between @0 and @f. Some nvramrc patches could maybe make Open Firmware probe the PCI bridge devices up to device number @1f. PCI bridges can be nested. In any case, each device number can have up to 8 functions numbered from 0 to 7.
The dingusppc CLI doesn't yet support adding devices to PCI bridges or adding function numbers 1 to 7.
