dingusppc/zdocs/grackle.md
joevt fca6cb11b6 Add info for possible grackle PCI devices
Devices that are not probed by Open Firmware might still be usable by Mac OS X or Linux if they can enumerate PCI devices without using Open Firmware's device tree.
A patch in nvramrc can make Open Firmware probe all the devices.
The point is that the emulation does not need to be limited to 5 slots.
2022-08-22 17:07:50 -07:00

43 lines
1.9 KiB
Markdown
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

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.
By default, Grackle operates on Address Map B.
CONFIG_ADDR can be found at any address in the range 0xFEC000000xFEDFFFFF, while CONFIG_DAT can be found at any address in the range 0xFEE000000xFEEFFFFF. The device trees also establish 0xFEF00000 as the 8259 interrupt acknowledgement register.
PCI Config addresses work as follows:
bus << 16 | device << 11 | function << 8 | offset
# Revisions
Revisions under 4.0 could allow up to 75 MHz, whereas 4.0 and newer can allow up to 83 MHz.
# General Data
Vendor ID: 0x1057 (Motorola)
Device ID: 0x0002 (MPC106)
Within the Mac's own device tree, this is usually device 0.
It also spans for 0x7F000000 bytes starting from 0x80000000.
# Adding PCI devices to dingusppc
The dingusppc CLI can add known PCI devices to a PCI slot (A1, B1, C1).
Only the following device numbers are probed by Open Firmware:
- @0 used by pci [grackle]
- @c slot PERCH interrupt 0x1c
- @d slot A1 interrupt 0x17
- @e slot B1 interrupt 0x18
- @f slot C1 interrupt 0x19
- @10 used by mac-io [heathrow] which includes many devices with different interrupts
- @12 slot F1 interrupt 0x16 used by AtiRageGT or AtiRagePro
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 devices numbers even if they are not probed by Open Firmware.