GTS AXI Streaming Intel® FPGA IP for PCI Express* User Guide

ID 813754
Date 8/07/2024
Public
Document Table of Contents

4.9. Tag Allocation

The x4 controller does not support the 10-bit tag requester capability, but x8 controller does. Both controllers does support the 10-bit complete capability. x8 controllers can allow up to 512 outstanding NPRs with valid tag values ranging from 0 to 511, while x4 controllers can allow up to 256 outstanding Non-Posted Requests tag only, with a valid range of 0 to 255.

If you want to use both, 10-bit tag and 8 bit tag, there is limitation on the tag allocation for 10 bit tag and 8 bit tag. The LSB 8 bits of 8-bit tags cannot be shared with LSB 8 bits of 10-bit tags. For example, if you want to use 64 tags for 8-bit tag and use rest of tags as 10-bit tag, you can partition tag space as follows.

Smaller tag: 0 ~ 63

10-bit tag: 320 ~ 511, 576 ~ 767

Note: All PFs and their associated VFs share the same tag space. This means that different PFs and VFs cannot have outstanding tags having the same tag values.