IBM RS/6000 44P 270 Service Manual page 29

For planars, cards, and non-SCSI devices, the location code is defined as follows:
AB-CD-EF-GH
| | | |
| | | Device/FRU/Port ID
| | Connector ID
| devfunc Number, Adapter Number or Physical Location
Bus Type or PCI Parent Bus
v The AB value identifies a bus type or PCI parent bus as assigned by the firmware.
v The CD value identifies adapter number, the adapter's devfunc number, or physical
location. The devfunc number is defined as the PCI device number times 8, plus the
function number.
v The EF value identifies a connector.
v The GH value identifies a port, address, device, or FRU.
Adapters and cards are identified only with AB-CD.
The possible values for AB are:
00 Processor bus
01 ISA bus
02 EISA bus
03 MCA bus
04 PCI bus used in the case where the PCI bus cannot be identified
05 PCMCIA buses
xy For PCI adapters where x is equal to or greater than 1. The x and y are characters in the
range of 0-9, A-H, J-N, P-Z (O, I, and lower case are omitted) and are equal to the parent
bus's "ibm, aix-location" open firmware property.
The possible values for CD depend on the adapter/card:
v For pluggable PCI adapters/cards, CD is the device's devfunc number (PCI device
number times 8, plus the function number). The C and D are characters in the range
of 0-9, and A-F (hex numbers). Location codes therefore uniquely identify multiple
adapters on individual PCI cards.
v For pluggable ISA adapters, CD is equal to the order of the ISA cards
defined/configured either by SMIT or the ISA Adapter Configuration Service Aid.
v For integrated ISA adapters, CD is equal to a unique code identifying the ISA
adapter. In most cases, this code is equal to the adapter's physical location code. In
cases where a physical location code is not available, CD will be FF.
EF is the connector ID, used to identify the adapter's connector to which a resource is
attached.
GH is used to identify a port, device, or FRU. For example:
v For async devices, GH defines the port on the fanout box. The values are 00 to 15.
v For a diskette drive, H identifies either diskette drive 1 or 2. G is always 0.
v For all other devices, GH is equal to 00.
Chapter 1. Reference Information
11