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Extension of BUID to id physical & logical hierarchy in PCI Disclosure Number: IPCOM000010287D
Original Publication Date: 2002-Nov-18
Included in the Prior Art Database: 2002-Nov-18
Document File: 1 page(s) / 40K

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A Bus Unit Identifier (BUID) was created to route I/O to physical microchips found in a Remote I/O (RIO) environment. By expanding the BUID a physical representation of the environment can be described.

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Extension of BUID to id physical & logical hierarchy in PCI

A BUID is a unique identifier that allows routing of data to and from I/O devices located on a Remote I/O bus. BUID's are commonly used on systems that contain multiple identical busses. While not limited to, an example of multiple busses would be many PCI busses in a single system.

The problem with a BUID is that it can not identify all of the physical and logical I/O devices in the Remote I/O system. The invention of the Extended BUID allows for all entities to be uniquely identified.

The Extended BUID is a 32 bit number. The 32 bits of the Extended BUID are bit mapped into groups. Each group represents different entities found in a RIO environment. Those entities are the PCI bridge number, EADS number, PHB number, drawer number and RIO chip number.

There is a table for each PCI bridge in the RIO environment. Each table will contain a 32 bit Extended BUID. The Extended BUID is created when the machine is instantiating RTAS (Run Time Abstraction Services). The Extended BUID is created by looping through a table that identify the entities of the RIO environment and assigning the indexes into those tables to the associated group in the Extended BUID.

An example of the Extended BUID is as follows... Extended BUID number is BIN: 0000 0000 0001 0100 0000 0000 0111 0011
HEX: 0 0 1 4 0 0 7 3

This Extended BUID uniquely identifies the 5th PCI Bridge on the second EADS chip located under the 2nd PHB located in se...