usbf_idma.v

USB硬件设计代码

always @(posedge clk)
`endif
	if(!rst)			sizd_c <= 14'h3fff;
	else
	if(tx_dma_en || tx_dma_en_r)	sizd_c <= size;
	else
	if(siz_dec)			sizd_c <= sizd_c - 14'h1;

assign siz_dec = (rd_first & mack_r) | (rd_next & (sizd_c != 14'h0));

assign sizd_is_zero_d = sizd_c == 14'h0;

always @(posedge clk)
	sizd_is_zero <= sizd_is_zero_d;

// Size Counter (counting up from zero)
`ifdef USBF_ASYNC_RESET
always @(posedge clk or negedge rst)
`else
always @(posedge clk)
`endif
	if(!rst)		sizu_c <= 11'h0;
	else
	// Do I need to add "abort" in the next line ???
	if(rx_dma_en_r)		sizu_c <= 11'h0;
	else
	if(siz_inc)		sizu_c <= sizu_c + 11'h1;

assign siz_inc = rx_data_valid_r;

// DMA Done Indicator
always @(posedge clk)
	idma_done <= (rx_data_done_r | sizd_is_zero_d); // & !tx_dma_en;

///////////////////////////////////////////////////////////////////
//
// RX Logic
//

always @(posedge clk)
	dtmp_sel_r <= dtmp_sel;

// Memory data input
always @(posedge clk)
	if(dtmp_sel_r)			dtmp_r <= mdin;
	else
	if(rx_data_valid_r)
	   begin
		if(adr_cb[1:0] == 2'h0)	dtmp_r[07:00] <= rx_data_st_r;
		if(adr_cb[1:0] == 2'h1)	dtmp_r[15:08] <= rx_data_st_r;
		if(adr_cb[1:0] == 2'h2)	dtmp_r[23:16] <= rx_data_st_r;
		if(adr_cb[1:0] == 2'h3)	dtmp_r[31:24] <= rx_data_st_r;
	   end

always @(posedge clk)
	word_done <= ((adr_cb[1:0] == 2'h3) & rx_data_valid_r) | wr_last;

always @(posedge clk)
	word_done_r <= word_done & !word_done_r;

// Store output data and address when we got a word
always @(posedge clk)
	if(word_done)	dout_r <= dtmp_r;

always @(posedge clk)
	wr_last <= (adr_cb[1:0] != 2'h0) & !rx_data_valid_r & wr_last_en;

always @(posedge clk)
	wr_done_r <= rx_data_done_r;

always @(posedge clk)
	wr_done <= wr_done_r;

///////////////////////////////////////////////////////////////////
//
// TX Logic
//

// Fill TX Buffers
always @(posedge clk)
	if(fill_buf0)	rd_buf0 <= mdin;

always @(posedge clk)
	if(fill_buf1)	rd_buf1 <= mdin;

always @(adrb_next or rd_buf0 or rd_buf1)
	case(adrb_next[2:0])	// synopsys full_case parallel_case
	   3'h0: tx_data_st = rd_buf0[07:00];
	   3'h1: tx_data_st = rd_buf0[15:08];
	   3'h2: tx_data_st = rd_buf0[23:16];
	   3'h3: tx_data_st = rd_buf0[31:24];
	   3'h4: tx_data_st = rd_buf1[07:00];
	   3'h5: tx_data_st = rd_buf1[15:08];
	   3'h6: tx_data_st = rd_buf1[23:16];
	   3'h7: tx_data_st = rd_buf1[31:24];
	endcase

assign fill_buf0 = !adr_cw[0] & mack_r;
assign fill_buf1 =  adr_cw[0] & mack_r;

assign	adrb_is_3 = adr_cb[1:0] == 2'h3;

`ifdef USBF_ASYNC_RESET
always @(posedge clk or negedge rst)
`else
always @(posedge clk)
`endif
	if(!rst)		send_data_r <= 1'b0;
	else
	if(rd_first)		send_data_r <= 1'b1;
	else
	if(((sizd_c==14'h1) && rd_next) || sizd_is_zero_d)	send_data_r <= 1'b0;

assign send_data = send_data_r | send_zero_length_r;

///////////////////////////////////////////////////////////////////
//
// IDMA Load/Store State Machine
//

// store incoming data to memory until rx_data done
// First pre-fetch data from memory, so that bytes can be stuffed properly

`ifdef USBF_ASYNC_RESET
always @(posedge clk or negedge rst)
`else
always @(posedge clk)
`endif
	if(!rst)	state <= IDLE;
	else		state <= next_state;

always @(state or mack_r or abort or rx_dma_en_r or tx_dma_en_r or 
	sizd_is_zero or wr_last or wr_done or rx_data_done_r2 or 
	rd_next or adrb_is_3 or send_zero_length_r)
   begin
	next_state = state;	// Default do not change state
	mreq_d = 1'b0;
	mwe_d = 1'b0;
	rd_first = 1'b0;
	dtmp_sel = 1'b0;
	wr_last_en = 1'b0;

	case(state)	// synopsys full_case parallel_case
	   IDLE:
		   begin

// synopsys translate_off
`ifdef USBF_VERBOSE_DEBUG
$display("IDMA: Entered IDLE state (%t)", $time);
`endif
`ifdef USBF_DEBUG
if(rst)
begin
if(rx_dma_en_r === 1'bx)	$display("ERROR: IDMA: IDLE: rx_dma_en_r is unknown. (%t)", $time);
if(tx_dma_en_r === 1'bx)	$display("ERROR: IDMA: IDLE: tx_dma_en_r is unknown. (%t)", $time);
if(abort === 1'bx)		$display("ERROR: IDMA: IDLE: abort is unknown. (%t)", $time);
end
`endif
// synopsys translate_on

			if(rx_dma_en_r && !abort)
			   begin
				next_state = WAIT_MRD;
			   end
			if(tx_dma_en_r && !abort && !send_zero_length_r)
			   begin
				next_state = MEM_RD1;
			   end
		   end

	   WAIT_MRD:	// Pre-fetch a word from memory
		   begin

// synopsys translate_off
`ifdef USBF_VERBOSE_DEBUG
$display("IDMA: Entered WAIT_MRD state (%t)", $time);
`endif
`ifdef USBF_DEBUG
if(abort === 1'bx)	$display("ERROR: IDMA: WAIT_MRD: abort is unknown. (%t)", $time);
if(mack_r === 1'bx)	$display("ERROR: IDMA: WAIT_MRD: mack_r is unknown. (%t)", $time);
`endif
// synopsys translate_on

			if(abort)	next_state = IDLE;
			else
			if(mack_r)	next_state = MEM_WR;
			else
			   begin
				dtmp_sel = 1'b1;
				mreq_d = 1'b1;
			   end
		   end

	   MEM_WR:
		   begin

// synopsys translate_off
`ifdef USBF_VERBOSE_DEBUG
$display("IDMA: Entered MEM_WR state (%t)", $time);
`endif
`ifdef USBF_DEBUG
if(abort === 1'bx)	$display("ERROR: IDMA: MEM_WR: abort is unknown. (%t)", $time);
if(rx_data_done_r2 === 1'bx)	$display("ERROR: IDMA: MEM_WR: rx_data_done_r2 is unknown. (%t)", $time);
`endif
// synopsys translate_on

			mwe_d = 1'b1;
			if(abort)			next_state = IDLE;
			else
			if(rx_data_done_r2)	
			   begin
				wr_last_en = 1'b1;
				next_state = MEM_WR1;
			   end

		   end
	   MEM_WR1:
		   begin

// synopsys translate_off
`ifdef USBF_VERBOSE_DEBUG
$display("IDMA: Entered MEM_WR1 state (%t)", $time);
`endif
`ifdef USBF_DEBUG
if(abort === 1'bx)	$display("ERROR: IDMA: MEM_WR1: abort is unknown. (%t)", $time);
if(wr_last === 1'bx)	$display("ERROR: IDMA: MEM_WR1: wr_last is unknown. (%t)", $time);
if(wr_done === 1'bx)	$display("ERROR: IDMA: MEM_WR1: wr_done is unknown. (%t)", $time);
`endif
// synopsys translate_on

			mwe_d = 1'b1;
			wr_last_en = 1'b1;
			if(abort)			next_state = IDLE;
			else
			if(wr_last)			next_state = MEM_WR2;
			else
			if(wr_done)			next_state = IDLE;
		   end

	   MEM_WR2:
		   begin

// synopsys translate_off
`ifdef USBF_VERBOSE_DEBUG
$display("IDMA: Entered MEM_WR2 state (%t)", $time);
`endif
`ifdef USBF_DEBUG
if(mack_r === 1'bx)	$display("ERROR: IDMA: MEM_WR2: mack_r is unknown. (%t)", $time);
`endif
// synopsys translate_on

			mwe_d = 1'b1;
			if(mack_r)			next_state = IDLE;
		   end

	   MEM_RD1:
		   begin

// synopsys translate_off
`ifdef USBF_VERBOSE_DEBUG
$display("IDMA: Entered MEM_RD1 state (%t)", $time);
`endif
`ifdef USBF_DEBUG
if(abort === 1'bx)	$display("ERROR: IDMA: MEM_RD1: abort is unknown. (%t)", $time);
if(mack_r === 1'bx)	$display("ERROR: IDMA: MEM_RD1: mack_r is unknown. (%t)", $time);
`endif
// synopsys translate_on

			mreq_d = 1'b1;
			if(mack_r)		rd_first = 1'b1;
			if(abort)		next_state = IDLE;
			else
			if(mack_r)		next_state = MEM_RD2;
		   end
	   MEM_RD2:
		   begin

// synopsys translate_off
`ifdef USBF_VERBOSE_DEBUG
$display("IDMA: Entered MEM_RD2 state (%t)", $time);
`endif
`ifdef USBF_DEBUG
if(abort === 1'bx)	$display("ERROR: IDMA: MEM_RD2: abort is unknown. (%t)", $time);
if(mack_r === 1'bx)	$display("ERROR: IDMA: MEM_RD2: mack_r is unknown. (%t)", $time);
`endif
// synopsys translate_on

			mreq_d = 1'b1;
			if(abort)		next_state = IDLE;
			else
			if(mack_r)		next_state = MEM_RD3;
		   end
	   MEM_RD3:
		   begin

// synopsys translate_off
`ifdef USBF_VERBOSE_DEBUG
$display("IDMA: Entered MEM_RD3 state (%t)", $time);
`endif
`ifdef USBF_DEBUG
if(abort === 1'bx)	$display("ERROR: IDMA: MEM_RD3: abort is unknown. (%t)", $time);
if(sizd_is_zero===1'bx) $display("ERROR: IDMA: MEM_RD3: sizd_is_zero is unknown. (%t)", $time);
if(adrb_is_3 === 1'bx)	$display("ERROR: IDMA: MEM_RD3: adrb_is_3 is unknown. (%t)", $time);
if(rd_next === 1'bx)	$display("ERROR: IDMA: MEM_RD3: rd_next is unknown. (%t)", $time);
`endif
// synopsys translate_on

			if(sizd_is_zero || abort)	next_state = IDLE;
			else
			if(adrb_is_3 && rd_next)	next_state = MEM_RD2;
		   end
	endcase

   end

endmodule