verilog axi 数据copy dma 代码

以下是一个简单的Verilog代码示例，用于实现AXI DMA数据传输：

module dma_copy (
  input aclk, aclkrst,
  input [31:0] src_addr,
  input [31:0] dst_addr,
  input [31:0] length,
  input start,
  output done
);

  // AXI DMA control registers
  reg [31:0] control;
  reg [31:0] status;
  
  // AXI DMA writer interface
  wire [31:0] axi_waddr;
  wire [31:0] axi_wdata;
  wire [3:0] axi_wstrb;
  wire axi_wvalid;
  wire axi_wready;
  
  // AXI DMA reader interface
  wire [31:0] axi_raddr;
  wire [31:0] axi_rdata;
  wire [3:0] axi_rstrb;
  wire axi_rvalid;
  wire axi_rready;
  
  // Internal read/write pointers and length counter
  reg [31:0] src_ptr;
  reg [31:0] dst_ptr;
  reg [31:0] len_count;
  
  // State machine states
  parameter IDLE = 0;
  parameter READ = 1;
  parameter WRITE = 2;
  reg [1:0] state;
  
  // Initialize state machine
  always @(posedge aclk) begin
    if (aclkrst) begin
      state <= IDLE;
      control <= 0;
      status <= 0;
      src_ptr <= 0;
      dst_ptr <= 0;
      len_count <= 0;
    end else begin
      case (state)
        IDLE: begin
          if (start) begin
            state <= READ;
            control <= 0x10002; // Start DMA transfer
            src_ptr <= src_addr;
            dst_ptr <= dst_addr;
            len_count <= length;
          end
        end
        READ: begin
          if (axi_rvalid) begin
            status <= axi_rdata; // Save DMA status
            state <= WRITE;
          end
          axi_raddr <= src_ptr;
          axi_rstrb <= 4'b1111;
          axi_rready <= 1;
        end
        WRITE: begin
          if (axi_wvalid) begin
            len_count <= len_count - 4; // Decrement length counter
            if (len_count == 0) begin
              state <= IDLE;
              control <= 0x10004; // Stop DMA transfer
              done <= 1;
            end else begin
              src_ptr <= src_ptr + 4; // Increment read pointer
              dst_ptr <= dst_ptr + 4; // Increment write pointer
              state <= READ;
            end
          end
          axi_waddr <= dst_ptr;
          axi_wdata <= axi_rdata;
          axi_wstrb <= 4'b1111;
          axi_wvalid <= axi_rvalid;
          axi_wready <= 1;
        end
      endcase
    end
  end

  // Connect AXI DMA writer interface
  axi_lite_slave #(
    .C_S_AXI_DATA_WIDTH(32),
    .C_S_AXI_ADDR_WIDTH(32)
  ) axi_writter (
    .aresetn(aclkrst),
    .aclk(aclk),
    .awaddr(axi_waddr),
    .awprot(3'b000),
    .awvalid(axi_wvalid),
    .awready(axi_wready),
    .awlen(0),
    .awsize(2),
    .awburst(2),
    .wdata(axi_wdata),
    .wstrb(axi_wstrb),
    .wvalid(axi_wvalid),
    .wready(axi_wready),
    .bresp(2'b00),
    .bvalid(),
    .bready()
  );
  
  // Connect AXI DMA reader interface
  axi_lite_slave #(
    .C_S_AXI_DATA_WIDTH(32),
    .C_S_AXI_ADDR_WIDTH(32)
  ) axi_reader (
    .aresetn(aclkrst),
    .aclk(aclk),
    .araddr(axi_raddr),
    .arprot(3'b000),
    .arvalid(axi_rvalid),
    .arready(axi_rready),
    .arlen(0),
    .arsize(2),
    .arburst(2),
    .rdata(axi_rdata),
    .rvalid(axi_rvalid),
    .rready(axi_rready),
    .rresp(2'b00),
    .rlast()
  );

endmodule

此代码使用AXI DMA接口在两个地址之间传输数据。 输入参数包括源地址，目标地址和数据长度，以及一个启动信号（start）和一个完成信号（done）。 AXI DMA控制寄存器和状态寄存器分别保存DMA传输的控制信息和状态信息。 在状态机中，从源地址读取数据并将其写入目标地址，直到数据传输完成。状态机的状态IDLE，READ和WRITE分别表示空闲，读取和写入。 AXI DMA的读取和写入接口分别连接到axi_reader和axi_writer模块。