Filter
Top Products
Intel
®
IXP400 Software
Programmer’s Guide IXP400 Software Version 2.0 April 2005
Document Number: 252539, Revision: 007 115
Access-Layer Components:
DMA Access Driver (IxDmaAcc) API 8
This chapter describes the Intel
®
IXP400 Software v2.0’s “DMA Access Driver” access-layer
component.
8.1 What’s New
There are no changes or enhancements to this component in software release 2.0.
8.2 Overview
The IxDmaAcc provides DMA capability to offload large data transfers between peripherals in the
IXP4XX product line and IXC1100 control plane processors memory map from the Intel XScale
core. The IxDmaAcc is designed to improve the Intel XScale core system performance by allowing
NPE to directly handle large transfers. The Direct Memory Access component (ixDmaAcc)
provides the capability to do DMA transfer between peripherals that are attached to AHB buses
(North AHB and South AHB buses). It also includes the APB bus, expansion bus, and PCI bus.
The ixDmaAcc component allows the client to access the NPEs’ DMA services. The DMA service
may run on one of the three NPEs. The appropriate NPE Microcode image with DMA services
must be running on the NPE dedicated for DMA support.
The ixDmaAcc component uses the services of IxQMgr and OSAL layer.
8.3 Features
The IxDmaAcc component provides these features:
• A DMA Access-layer API
• Clients’ parameters validation
• Queues DMA requests (FIFO) to the Queue Manager
8.4 Assumptions
The DMA service is predicated on the following assumptions:
• IxDmaAcc has no knowledge about the IXP4XX product line and IXC1100 control plane
processors memory map.The client needs to verify the validity of the source address and
destination address of the DMA transfer.