AXI4-Stream C2H Ports - 4.0 English

QDMA Subsystem for PCI Express Product Guide (PG302)

Document ID
Release Date
4.0 English
Table 1. AXI4-Stream C2H Port Descriptions
Port Name I/O Description


I It supports 4 data widths: 64 bits, 128 bits, 256 bits, and 512 bits. Every C2H data packet has a corresponding C2H completion packet.



32 bit CRC value for that beat.

IEEE 802.3 CRC-32 Polynomial

IP samples CRC value only when s_axis_c2h_tlast is asserted.

s_axis_c2h_ctrl_len [15:0] I Length of the packet. For ZERO byte write, the length is 0.

C2H stream packet data length is limited to 31 * c2h buffer size.

In older versions (such as 2018.3), C2H stream packet data length was limited to 7 * C2H buffer size.

ctrl_len is in bytes and should be valid in first beat of the packet.

s_axis_c2h_ctrl_qid [10:0] I Queue ID.
s_axis_c2h_ctrl_has_cmpt I 1'b1: The data packet has a completion.

1'b0: The data packet doesn't have a completion.

s_axis_c2h_ctrl_marker I Marker message used for making sure pipeline is completely flushed. After that, you can safely do queue invalidation.
s_axis_c2h_ctrl_port_id [2:0] I Port ID.
s_axis_c2h_ctrl_ecc[6:0] I Sideband protection for C2H control signals. Output of the Xilinx® Error Correction Code (ECC) core. ECC IP input is described below.
s_axis_c2h_mty [5:0] I Empty byte should be set in last beat.
s_axis_c2h_tvalid I Valid.
s_axis_c2h_tlast I Indicate last packet.
s_axis_c2h_tready O Ready.

To generate ECC signals for C2H control bus s_axis_c2h_ctrl_ecc[6:0], use Xilinx Error Correction Code IP. Signals that are used are listed below.

Input to ECC IP using ecc_gen_datain[56:0]

assign ecc_gen_datain[56:0] = { 24'h0, //reserved
                    s_axis_c2h_ctrl_has_cmpt_int, //has compt
                    s_axis_c2h_ctrl_marker_int, //marker
                    s_axis_c2h_ctrl_port_id, //port_id
                    1'b0, // reserved should be set to 0.
                    s_axis_c2h_ctrl_qid_int, // Qid 
                    s_axis_c2h_ctrl_len_int}; //length