Scalable Scatter-Gather DMA Intel® FPGA IP User Guide

ID 823097
Date 7/08/2024
Public

A newer version of this document is available. Customers should click here to go to the newest version.

Document Table of Contents

3.8.3. Responder Descriptor

Similar to data descriptor, the format of responder descriptors varies depending on the following data transfer type:
  • H2D Streaming Transfer
  • D2H Streaming Transfer
  • H2D Memory Transfer
Table below shows description of common fields of Responder Descriptor.
Table 24.  Responder Descriptor — Field Description
Field Description
DescrIDX

Unique Identifier for each descriptor. This value is updated to Q_EXTRACT_POINTER register when a descriptor data transfer is complete and Q_PREFETCH_POINTER register when the descriptor has been fetched by Prefetcher Engine.

Note: First descriptor DESC_IDX value is 1, not 0.
Length The actual number of bytes transferred, up to 32MB for maximum transfer.