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// ***************************************************************************
// ***************************************************************************
// Copyright 2013(c) Analog Devices, Inc.
// Author: Lars-Peter Clausen <lars@metafoo.de>
//
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without modification,
// are permitted provided that the following conditions are met:
// - Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// - Redistributions in binary form must reproduce the above copyright
// notice, this list of conditions and the following disclaimer in
// the documentation and/or other materials provided with the
// distribution.
// - Neither the name of Analog Devices, Inc. nor the names of its
// contributors may be used to endorse or promote products derived
// from this software without specific prior written permission.
// - The use of this software may or may not infringe the patent rights
// of one or more patent holders. This license does not release you
// from the requirement that you obtain separate licenses from these
// patent holders to use this software.
// - Use of the software either in source or binary form, must be run
// on or directly connected to an Analog Devices Inc. component.
//
// THIS SOFTWARE IS PROVIDED BY ANALOG DEVICES "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
// INCLUDING, BUT NOT LIMITED TO, NON-INFRINGEMENT, MERCHANTABILITY AND FITNESS FOR A
// PARTICULAR PURPOSE ARE DISCLAIMED.
//
// IN NO EVENT SHALL ANALOG DEVICES BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
// EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, INTELLECTUAL PROPERTY
// RIGHTS, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
// BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
// THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
// ***************************************************************************
// ***************************************************************************
module dmac_request_generator (
input req_aclk,
input req_aresetn,
output [ID_WIDTH-1:0] request_id,
input [ID_WIDTH-1:0] response_id,
input req_valid,
output reg req_ready,
input [BURSTS_PER_TRANSFER_WIDTH-1:0] req_burst_count,
input enable,
input pause,
output eot
);
parameter ID_WIDTH = 3;
parameter BURSTS_PER_TRANSFER_WIDTH = 17;
`include "inc_id.h"
/*
* Here we only need to count the number of bursts, which means we can ignore
* the lower bits of the byte count. The last last burst may not contain the
* maximum number of bytes, but the address_generator and data_mover will take
* care that only the requested ammount of bytes is transfered.
*/
reg [BURSTS_PER_TRANSFER_WIDTH-1:0] burst_count = 'h00;
reg [ID_WIDTH-1:0] id;
wire [ID_WIDTH-1:0] id_next = inc_id(id);
assign eot = burst_count == 'h00;
assign request_id = id;
always @(posedge req_aclk)
begin
if (req_aresetn == 1'b0) begin
burst_count <= 'h00;
id <= 'h0;
req_ready <= 1'b1;
end else if (enable == 1'b0) begin
req_ready <= 1'b1;
end else begin
if (req_ready) begin
if (req_valid && enable) begin
burst_count <= req_burst_count;
req_ready <= 1'b0;
end
end else if (response_id != id_next && ~pause) begin
if (eot)
req_ready <= 1'b1;
burst_count <= burst_count - 1'b1;
id <= id_next;
end
end
end
endmodule
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