pluto_hdl_adi/library/axi_dmac/response_generator.v

// ***************************************************************************
// ***************************************************************************
// Copyright 2013(c) Analog Devices, Inc.
//  Author: Lars-Peter Clausen <lars@metafoo.de>
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module dmac_response_generator (
	input clk,
	input resetn,

	input enable,
	output reg enabled,

	input [ID_WIDTH-1:0] request_id,
	output reg [ID_WIDTH-1:0] response_id,
	input sync_id,

	input eot,

	output resp_valid,
	input resp_ready,
	output resp_eot,
	output [1:0] resp_resp
);

parameter ID_WIDTH = 3;

`include "inc_id.h"
`include "resp.h"

assign resp_resp = RESP_OKAY;
assign resp_eot = eot;

assign resp_valid = request_id != response_id && enabled;

// We have to wait for all responses before we can disable the response handler
always @(posedge clk) begin
	if (resetn == 1'b0) begin
		enabled <= 1'b0;
	end else begin
		if (enable)
			enabled <= 1'b1;
		else if (request_id == response_id)
			enabled <= 1'b0;
	end
end

always @(posedge clk) begin
	if (resetn == 1'b0) begin
		response_id <= 'h0;
	end else begin
		if ((resp_valid && resp_ready) ||
			(sync_id && response_id != request_id))
			response_id <= inc_id(response_id);
	end
end

endmodule