Output of a slave component using HLS

NSuku1 · ‎02-06-2019

Hi all,

I'm new to FPGA design and HLS compiler. I tried developing a matrix slave component which needs to interact with an Avalon memory mapped master interface.

hls_avalon_slave_component
component void matrix_6x6 (float *input, int mode, float *output) {
	float cParam[6][6] = 
		{
		{1, 1, 1, 1, 1, 1},
		{1, 1, 1, 1, 1, 1},
		{1, 1, 1, 1, 1, 1},
		{1, 1, 1, 1, 1, 1},
		{1, 1, 1, 1, 1, 1},
		{1, 1, 1, 1, 1, 1},
		};
	float nParam[6][6]= 
	{
		{-0.3180, 0.5319, 3.9623, 0.0010, 0.0689, 0.0173},
		{-0.3203, -0.5453, 3.9833, -0.0005, -0.1027, 0.0303},
		{0.5932, 0.0012, 3.8879, -0.0021, 0.0202, -0.1327},
		{-0.0012, -0.0240, 0.0071, 0.2665, 3.8957, 0.3263},
		{0.0159, 0.0103, 0.0080, 0.3353, -1.7172, 2.7507},
		{-0.0187, 0.0115, 0.0152, 0.3322, -2.2704, -3.0780},
	};
	float inputData[6];
	float resultBuffer[6];
	float sum = 0.0f;
		
	
		#pragma unroll
		for (int j=0; j<6; j++){
			for (int k=0; k<6; k++){
				if (mode == 0) {
					sum  = sum + (input[j] * cParam[k][j]);
				} else if (mode == 1) {
					sum  = sum + (input[j] * nParam[k][j]);
				} else {
					sum  = sum + (input[j] * cParam[k][j]);
				}
			}
		
			resultBuffer[j] = sum;
			sum = 0.0f;
		}	
	
	//output = input*params
	
	#pragma unroll
	for (int row=0; row<6; row++) {
		output[row] = resultBuffer[row];
	}			
}

On generating the verilog output, I got the following interface to be used in the top level module.

matrix_6x6 matrix_6x6_inst (
  // Interface: clock (clock end)
  .clock               ( ), // 1-bit clk input
  // Interface: reset (reset end)
  .resetn              ( ), // 1-bit reset_n input
  // Interface: irq (interrupt end)
  .done_irq            ( ), // 1-bit irq output
  // Interface: input0 (conduit sink)
  .input0              ( ), // 64-bit data input
  // Interface: mode (conduit sink)
  .mode                ( ), // 32-bit data input
  // Interface: output0 (conduit sink)
  .output0             ( ), // 64-bit data input
  // Interface: avmm_0_rw (avalon start)
  .avmm_0_rw_address   ( ), // 64-bit address output
  .avmm_0_rw_byteenable( ), // 8-bit byteenable output
  .avmm_0_rw_read      ( ), // 1-bit read output
  .avmm_0_rw_readdata  ( ), // 64-bit readdata input
  .avmm_0_rw_write     ( ), // 1-bit write output
  .avmm_0_rw_writedata ( ), // 64-bit writedata output
  // Interface: avs_cra (avalon end)
  .avs_cra_read        ( ), // 1-bit read input
  .avs_cra_write       ( ), // 1-bit write input
  .avs_cra_address     ( ), // 2-bit address input
  .avs_cra_writedata   ( ), // 64-bit writedata input
  .avs_cra_byteenable  ( ), // 8-bit byteenable input
  .avs_cra_readdata    ( )  // 64-bit readdata output
);

I want to access the output memory location for which I did *output in the HLS code. But, in the interface, it was generated as input.

Am I missing something here?

Kindly clarify,

Nivetha

MuhammadAr_U_Intel · ‎02-19-2019

Hi Nivetha, I suspect this is due to your component return type is set to void. Try using a return type as "int" and return the value from component. You should see an output named "returndata" in HLS output. You may refer to some basic HLS example with return type "int" such as "counter" example provided with HLS distribution. Located in <HLS install dir>/examples/counter I hope my reply is helpful to you. Thanks, Arslan