100 lines
3.7 KiB
Verilog
100 lines
3.7 KiB
Verilog
// ***************************************************************************
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// ***************************************************************************
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// Copyright 2013(c) Analog Devices, Inc.
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// Author: Lars-Peter Clausen <lars@metafoo.de>
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//
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// All rights reserved.
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//
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// Redistribution and use in source and binary forms, with or without modification,
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// are permitted provided that the following conditions are met:
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// - Redistributions of source code must retain the above copyright
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// notice, this list of conditions and the following disclaimer.
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// - Redistributions in binary form must reproduce the above copyright
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// notice, this list of conditions and the following disclaimer in
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// the documentation and/or other materials provided with the
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// distribution.
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// - Neither the name of Analog Devices, Inc. nor the names of its
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// contributors may be used to endorse or promote products derived
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// from this software without specific prior written permission.
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// - The use of this software may or may not infringe the patent rights
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// of one or more patent holders. This license does not release you
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// from the requirement that you obtain separate licenses from these
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// patent holders to use this software.
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// - Use of the software either in source or binary form, must be run
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// on or directly connected to an Analog Devices Inc. component.
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//
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// THIS SOFTWARE IS PROVIDED BY ANALOG DEVICES "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
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// INCLUDING, BUT NOT LIMITED TO, NON-INFRINGEMENT, MERCHANTABILITY AND FITNESS FOR A
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// PARTICULAR PURPOSE ARE DISCLAIMED.
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//
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// IN NO EVENT SHALL ANALOG DEVICES BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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// EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, INTELLECTUAL PROPERTY
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// RIGHTS, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
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// BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
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// THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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// ***************************************************************************
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// ***************************************************************************
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module dmac_request_generator (
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input req_aclk,
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input req_aresetn,
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output [C_ID_WIDTH-1:0] request_id,
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input [C_ID_WIDTH-1:0] response_id,
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input req_valid,
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output reg req_ready,
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input [BURST_COUNT_WIDTH:0] req_burst_count,
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input enable,
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input pause,
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output eot
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);
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parameter C_ID_WIDTH = 3;
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parameter C_ADDR_ALIGN_BITS = 3;
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parameter C_BURST_ALIGN_BITS = 7;
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parameter C_DMA_LENGTH_WIDTH = 24;
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localparam BURST_COUNT_WIDTH = C_DMA_LENGTH_WIDTH - C_BURST_ALIGN_BITS;
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`include "inc_id.h"
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/*
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* Here we only need to count the number of bursts, which means we can ignore
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* the lower bits of the byte count. The last last burst may not contain the
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* maximum number of bytes, but the address_generator and data_mover will take
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* care that only the requested ammount of bytes is transfered.
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*/
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reg [BURST_COUNT_WIDTH-1:0] burst_count = 'h00;
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reg [C_ID_WIDTH-1:0] id;
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wire [C_ID_WIDTH-1:0] id_next = inc_id(id);
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assign eot = burst_count == 'h00;
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assign request_id = id;
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always @(posedge req_aclk)
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begin
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if (req_aresetn == 1'b0) begin
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burst_count <= 'h00;
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id <= 'h0;
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req_ready <= 1'b1;
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end else begin
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if (req_ready) begin
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if (req_valid && enable) begin
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burst_count <= req_burst_count;
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req_ready <= 1'b0;
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end
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end else if (response_id != id_next && ~pause) begin
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if (eot)
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req_ready <= 1'b1;
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burst_count <= burst_count - 1'b1;
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id <= id_next;
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end
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end
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end
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endmodule
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