Browse Prior Art Database

Method to Provide Direct Memory Access by Processor Device Drivers to Coprocessor Effective Address Space

IP.com Disclosure Number: IPCOM000061709D
Original Publication Date: 1986-Sep-01
Included in the Prior Art Database: 2005-Mar-09
Document File: 2 page(s) / 39K

Publishing Venue

IBM

Related People

O'Quin, JT: AUTHOR

Abstract

A method is described to permit a device driver executing in the processor to Direct Memory Access (DMA) to the Coprocessor effective address space. In the system shown in the figure, device drivers executing in the processor can be used to emulate operations for applications executing in the Coprocessor. To successfully emulate these operations, the device driver must be able to access the Coprocessor effective address space. Memory in the Coprocessor effective address space may reside in either system or bus memory address space. The Virtual Resource Manager (VRM) service, referred to as $STDMA, allows the caller to indicate if the request is to be performed to the Coprocessor effective address space. This service will reverse translate the address and initialize the Input/Output Channel Controller (IOCC) appropriately.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 100% of the total text.

Page 1 of 2

Method to Provide Direct Memory Access by Processor Device Drivers to Coprocessor Effective Address Space

A method is described to permit a device driver executing in the processor to Direct Memory Access (DMA) to the Coprocessor effective address space. In the system shown in the figure, device drivers executing in the processor can be used to emulate operations for applications executing in the Coprocessor. To successfully emulate these operations, the device driver must be able to access the Coprocessor effective address space. Memory in the Coprocessor effective address space may reside in either system or bus memory address space. The Virtual Resource Manager (VRM) service, referred to as $STDMA, allows the caller to indicate if the request is to be performed to the Coprocessor effective address space. This service will reverse translate the address and initialize the Input/Output Channel Controller (IOCC) appropriately. The device drivers do not need to know anything about the Coprocessor or its current memory configuration. They can emulate operations for the Coprocessor applications and appear as if they are executing in the Coprocessor.

1

Page 2 of 2

2

[This page contains 2 pictures or other non-text objects]