module dmac_2d_transfer #(

  parameter DMA_AXI_ADDR_WIDTH = 32,
  parameter DMA_LENGTH_WIDTH = 24,
  parameter BYTES_PER_BURST_WIDTH = 7,
  parameter BYTES_PER_BEAT_WIDTH_SRC = 3,
  parameter BYTES_PER_BEAT_WIDTH_DEST = 3)(

  input req_aclk,
  input req_aresetn,

  input req_valid,
  output reg req_ready,

  input [DMA_AXI_ADDR_WIDTH-1:BYTES_PER_BEAT_WIDTH_DEST] req_dest_address,
  input [DMA_AXI_ADDR_WIDTH-1:BYTES_PER_BEAT_WIDTH_SRC] req_src_address,
  input [DMA_LENGTH_WIDTH-1:0] req_x_length,
  input [DMA_LENGTH_WIDTH-1:0] req_y_length,
  input [DMA_LENGTH_WIDTH-1:0] req_dest_stride,
  input [DMA_LENGTH_WIDTH-1:0] req_src_stride,
  input req_sync_transfer_start,
  input req_last,

  output reg req_eot,
  output reg [BYTES_PER_BURST_WIDTH-1:0] req_measured_burst_length,
  output reg req_response_partial,
  output reg req_response_valid,
  input req_response_ready,

  input out_abort_req,

  output reg out_req_valid,
  input out_req_ready,
  output [DMA_AXI_ADDR_WIDTH-1:BYTES_PER_BEAT_WIDTH_DEST] out_req_dest_address,
  output [DMA_AXI_ADDR_WIDTH-1:BYTES_PER_BEAT_WIDTH_SRC] out_req_src_address,
  output [DMA_LENGTH_WIDTH-1:0] out_req_length,
  output reg out_req_sync_transfer_start,
  output out_req_last,

  input out_eot,
  input [BYTES_PER_BURST_WIDTH-1:0] out_measured_burst_length,
  input out_response_partial,
  input out_response_valid,
  output reg out_response_ready = 1'b1

);

reg [DMA_AXI_ADDR_WIDTH-1:BYTES_PER_BEAT_WIDTH_DEST] dest_address = 'h00;
reg [DMA_AXI_ADDR_WIDTH-1:BYTES_PER_BEAT_WIDTH_SRC] src_address = 'h00;
reg [DMA_LENGTH_WIDTH-1:0] x_length = 'h00;
reg [DMA_LENGTH_WIDTH-1:0] y_length = 'h00;
reg [DMA_LENGTH_WIDTH-1:0] dest_stride = 'h0;
reg [DMA_LENGTH_WIDTH-1:0] src_stride = 'h00;

reg gen_last = 'h0;

reg [1:0] req_id = 'h00;
reg [1:0] eot_id = 'h00;
reg [3:0] last_req = 'h00;

wire out_last;

assign out_req_dest_address = dest_address;
assign out_req_src_address = src_address;
assign out_req_length = x_length;
assign out_last = y_length == 'h00;

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 == 1'b1 && out_req_ready == 1'b1) begin
      req_id <= req_id + 1'b1;
    end

    if (out_eot == 1'b1 && out_response_valid == 1'b1 && out_response_ready == 1'b1) begin
      eot_id <= eot_id + 1'b1;
      req_eot <= last_req[eot_id];
    end else begin
      req_eot <= 1'b0;
    end
  end
end

always @(posedge req_aclk) begin
  if (out_req_valid == 1'b1 && out_req_ready == 1'b1) begin
    last_req[req_id] <= out_last;
  end
end

always @(posedge req_aclk) begin
  if (out_response_valid == 1'b1 && out_response_ready == 1'b1) begin
    req_measured_burst_length <= out_measured_burst_length;
    req_response_partial <= out_response_partial;
  end
end

always @(posedge req_aclk) begin
  if (out_response_valid == 1'b1 && out_response_ready == 1'b1) begin
    req_response_valid <= 1'b1;
  end else if (req_response_ready == 1'b1) begin
    req_response_valid <= 1'b0;
  end
end

always @(posedge req_aclk) begin
  if (req_aresetn == 1'b0) begin
    out_response_ready <= 1'b1;
  end else if (out_response_ready == 1'b1) begin
    out_response_ready <= ~out_response_valid;
  end else if (req_response_ready == 1'b1) begin
    out_response_ready <= 1'b1;
  end
end

always @(posedge req_aclk) begin
  if (req_ready == 1'b1 && req_valid == 1'b1) 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;
    gen_last <= req_last;
  end else if (out_abort_req == 1'b1) begin
    y_length <= 0;
  end else if (out_req_valid == 1'b1 && out_req_ready == 1'b1) begin
    dest_address <= dest_address + dest_stride[DMA_LENGTH_WIDTH-1:BYTES_PER_BEAT_WIDTH_DEST];
    src_address <= src_address + src_stride[DMA_LENGTH_WIDTH-1:BYTES_PER_BEAT_WIDTH_SRC];
    y_length <= y_length - 1'b1;
    out_req_sync_transfer_start <= 1'b0;
  end
end

always @(posedge req_aclk) begin
  if (req_aresetn == 1'b0) begin
    req_ready <= 1'b1;
    out_req_valid <= 1'b0;
  end else begin
    if (req_ready == 1'b1 && req_valid == 1'b1) begin
      req_ready <= 1'b0;
      out_req_valid <= 1'b1;
    end else if (out_req_valid == 1'b1 && out_req_ready == 1'b1 &&
                 out_last == 1'b1) begin
      out_req_valid <= 1'b0;
      req_ready <= 1'b1;
    end
  end
end

assign out_req_last = out_last & gen_last;

endmodule