GTS AXI Multichannel DMA IP for PCI Express* User Guide

ID 847470
Date 8/25/2025
Public
Document Table of Contents

B.2.4. Request Structures

To request a DMA operation, the application uses the rte_mbuf structure, which contains packet information such as the physical address of segment buffer, length of the data in this descriptor, number of segments, 8-byte userdata which is used to signal the SOF and EOF of data.

Note: For the AXI-S design, the application should pass the SOF, EOF and metadata to the driver in the private structure added in the rte_mbuf structure. SOF and EOF flags should be updated based on the file size. For example, if file_size = 127, 0th descriptor should contain the SOF flag (should be set) and 126th descriptor should contain the EOF flag (should be set).

Metadata is private information and can be used for any purpose.

Structure of Private Data

struct private_data {
      uint64_t flags; /* SOF, EOF */
      uint64_t metadata; /* Private meta data */
};