// ***************************************************************************
// ***************************************************************************
// 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_2d_transfer (
	input req_aclk,
	input req_aresetn,

	input req_valid,
	output reg req_ready,

	input [31:C_BYTES_PER_BEAT_WIDTH_DEST] req_dest_address,
	input [31:C_BYTES_PER_BEAT_WIDTH_SRC] req_src_address,
	input [C_DMA_LENGTH_WIDTH-1:0] req_x_length,
	input [C_DMA_LENGTH_WIDTH-1:0] req_y_length,
	input [C_DMA_LENGTH_WIDTH-1:0] req_dest_stride,
	input [C_DMA_LENGTH_WIDTH-1:0] req_src_stride,
	input req_sync_transfer_start,
	output reg req_eot,
	
	output reg out_req_valid,
	input out_req_ready,
	output [31:C_BYTES_PER_BEAT_WIDTH_DEST] out_req_dest_address,
	output [31:C_BYTES_PER_BEAT_WIDTH_SRC] out_req_src_address,
	output [C_DMA_LENGTH_WIDTH-1:0] out_req_length,
	output reg out_req_sync_transfer_start,
	input out_eot
);

parameter C_DMA_LENGTH_WIDTH = 24;
parameter C_BYTES_PER_BEAT_WIDTH_SRC = 3;
parameter C_BYTES_PER_BEAT_WIDTH_DEST = 3;

reg [31:C_BYTES_PER_BEAT_WIDTH_DEST] dest_address;
reg [31:C_BYTES_PER_BEAT_WIDTH_SRC] src_address;
reg [C_DMA_LENGTH_WIDTH-1:0] x_length;
reg [C_DMA_LENGTH_WIDTH-1:0] y_length;
reg [C_DMA_LENGTH_WIDTH-1:0] dest_stride;
reg [C_DMA_LENGTH_WIDTH-1:0] src_stride;

reg [1:0] req_id;
reg [1:0] eot_id;
reg [3:0] last_req;

assign out_req_dest_address = dest_address;
assign out_req_src_address = src_address;
assign out_req_length = x_length;

always @(posedge req_aclk)
begin
	if (req_aresetn == 1'b0) begin
		req_id <= 2'b0;
		eot_id <= 2'b0;
		req_eot <= 1'b0;
	end else begin
		if (out_req_valid && out_req_ready) begin
			req_id <= req_id + 1'b1;
			last_req[req_id] <= y_length == 0;
		end
		req_eot <= 1'b0;
		if (out_eot) begin
			eot_id <= eot_id + 1'b1;
			req_eot <= last_req[eot_id];
		end
	end
end

always @(posedge req_aclk)
begin
	if (req_aresetn == 1'b0) begin
		dest_address <= 'h00;
		src_address <= 'h00;
		x_length <= 'h00;
		y_length <= 'h00;
		dest_stride <= 'h00;
		src_stride <= 'h00;
		req_ready <= 1'b1;
		out_req_valid <= 1'b0;
		out_req_sync_transfer_start <= 1'b0;
	end else begin
		if (req_ready) begin
			if (req_valid) begin
				dest_address <= req_dest_address;
				src_address <= req_src_address;
				x_length <= req_x_length;
				y_length <= req_y_length;
				dest_stride <= req_dest_stride;
				src_stride <= req_src_stride;
				out_req_sync_transfer_start <= req_sync_transfer_start;
				req_ready <= 1'b0;
				out_req_valid <= 1'b1;
			end
		end else begin
			if (out_req_valid && out_req_ready) begin
				dest_address <= dest_address + dest_stride[C_DMA_LENGTH_WIDTH-1:C_BYTES_PER_BEAT_WIDTH_DEST];
				src_address <= src_address + src_stride[C_DMA_LENGTH_WIDTH-1:C_BYTES_PER_BEAT_WIDTH_SRC];
				y_length <= y_length - 1'b1;
				out_req_sync_transfer_start <= 1'b0;
				if (y_length == 0) begin
					out_req_valid <= 1'b0;
					req_ready <= 1'b1;
				end
			end
		end
	end
end

endmodule