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Device Discovery of I/O Processor-less I/O Adapters and Integration into a System with I/O Processor-based I/O Adapters

IP.com Disclosure Number: IPCOM000022097D
Original Publication Date: 2004-Feb-24
Included in the Prior Art Database: 2004-Feb-24
Document File: 1 page(s) / 46K

Publishing Venue

IBM

Abstract

Integration of I/O Adapters (IOAs) which do not require I/O Processors (IOPs) into a system with IOP-based IOAs for transitioning systems from IOP-based to IOP-less can be done through use of the Peripheral Component Interconnect (PCI) Configuration Information.

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Device Discovery of I/O Processor-less I/O Adapters and Integration into a System with I/O Processor-based I/O Adapters

Disclosed is a concept which allows integration of I/O Adapters (IOAs) which do not require I/O Processors (IOPs) into a system with IOP-based IOAs.

  Most systems today do not use IOPs to drive IOAs. In order to migrate IOP-based systems to IOP-less systems, a method was devised to provide transitional systems where both IOP-based and IOP-less IOAs could coexist. In order to minimize the design impacts to transitional systems, a decision was made to present a virtual IOP which went with each IOP-less IOA. This virtual IOP would be a software object only. The IOP-less IOAs are determined during device discovery, and the virtual IOPs created at this time.

  A method was needed to determine if an IOA was an IOP-less IOA. IOAs which are IOP-based still get assigned to an IOP. It was decided that an IOA could be uniquely identified from the following information from the device peripheral component interconnect (PCI) configuration space: the Device ID, the Vendor ID, the subsystem Device ID and the subsystem Vendor ID. This information is entered into an IOP-less IOA Configuration map, along with a constructor pointer, before the device discovery phase of system IPL. Each IOA found during device discovery can be checked to see if its configuration information is in this map. If it is in the map, it is an IOP-less IOA and a virtual IOP object is constructed. If it is not in the map, it can be assigned to an IOP.

  This requires that each IOA can be uniquely identified by the PCI Configuration Device ID, Vendor ID, subsystem Device ID and subsystem Vendor ID. In cases where two similar IOAs from one vendor have the same configuration infor...