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

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

8.6.5.2. TPH Requester Capability Register

Address: Offset 0x4

This is a read-only register that specifies the capabilities associated with the implementation of the TPH in the device. Note that ST Table must be implemented in the user logic if present. The capability does not hold the ST table.

Table 82.  TPH Requester Capability Register Description
Bit Location Description Attributes Default
0

No ST Mode Supported.

When set to 1, indicates that this Function supports the “No ST Mode” for the generation of TPH Steering Tags. In the No ST Mode, the device must use a Steering Tag value of 0 for all requests.

This bit is hardwired to 1, as all TPH Requesters are required to support the No ST Mode of operation.

RO 1
1

Interrupt Vector Mode Supported.

A setting of 1 indicates that the Function supports the Interrupt Vector Mode for TPH Steering Tag generation. In the Interrupt Vector Mode, Steering Tags are attached to MSI/MSI-X interrupt requests. The Steering Tag for each interrupt request is selected by the MSI/MSI-X interrupt vector number.

RO Programmable
2

Device-Specific Mode Supported.

A setting of 1 indicates that the Function supports the Device-Specific Mode for TPH Steering Tag generation. The client typically choses the Steering Tag values from the ST Table, but is not required to do so.

RO Programmable
7:3 Reserved RO 0
8

Extended TPH Requester Supported.

When set to 1, indicates that the Function is capable of generating requests with 16-bit Steering Tags, using TLP Prefix.

RO Programmable
10:9

ST Table Location

The setting of this field indicates if a Steering Tag Table is implemented for this Function, and its location if present.
  • 0 = ST Table not present
  • 1 = ST Table in the TPH Requester Capability Structure
  • 2 = ST values stored in the MSI-X Table in client RAM
  • 3 = Reserved

Valid settings are 0 or 2.

RO Programmable
15:11 Reserved RO 0
26:16

ST Table Size.

Specifies the number of entries in the Steering Tag Table (0 = 1 entry, 1 = 2 entries, and so on). Max limit is 2048 entries when located in the MSI-X table. Each entry is 8 bits long.

RO Programmable
31:17 Reserved RO 0