u1p: gpif-to-fx2 path should now handle arbitrary sized packets, up to 2KB

1 files changed, 29 insertions, 22 deletions

diff --git a/usrp2/gpif/gpif_rd.v b/usrp2/gpif/gpif_rd.v
index 76db72d8a..e79b275b3 100644
--- a/usrp2/gpif/gpif_rd.v
+++ b/usrp2/gpif/gpif_rd.v
@@ -10,7 +10,7 @@ module gpif_rd
    output [31:0] debug
    );
    
-   wire [18:0] 	data_o, resp_o;
+   wire [17:0] 	data_o, resp_o; // drop occ bit from input data
    wire 	final_rdy_data, final_rdy_resp;
    
    // 33/257 Bug Fix
@@ -24,49 +24,56 @@ module gpif_rd
        read_count <= 0;
 
    // Data Path
-   wire [18:0] 	data_int;
+   wire [17:0] 	data_int;
    wire 	src_rdy_int, dst_rdy_int;
-   fifo_2clock_cascade #(.WIDTH(19), .SIZE(4)) rd_fifo_2clk
-     (.wclk(sys_clk), .datain(data_i), .src_rdy_i(src_rdy_i), .dst_rdy_o(dst_rdy_o), .space(),
+   fifo_2clock_cascade #(.WIDTH(18), .SIZE(4)) rd_fifo_2clk
+     (.wclk(sys_clk), .datain(data_i[17:0]), .src_rdy_i(src_rdy_i), .dst_rdy_o(dst_rdy_o), .space(),
       .rclk(~gpif_clk), .dataout(data_int), .src_rdy_o(src_rdy_int), .dst_rdy_i(dst_rdy_int), .occupied(),
       .arst(sys_rst));
 
-   // FIXME -- handle short packets
-   wire 	send_data_line = gpif_rd & ~gpif_ep & ~read_count[8];
+   reg [7:0] 	packet_count;
+   reg 		do_padding;
+   wire 	consume_data_line = gpif_rd & ~gpif_ep & ~read_count[8] & ~do_padding;
+   wire 	produce_eop = src_rdy_int & dst_rdy_int & data_int[17];
+   wire 	consume_sop = consume_data_line & final_rdy_data & data_o[16];
+   wire 	consume_eop = consume_data_line & final_rdy_data & data_o[17];
    
-   fifo_cascade #(.WIDTH(19), .SIZE(9)) rd_fifo
+   fifo_cascade #(.WIDTH(18), .SIZE(10)) rd_fifo
      (.clk(~gpif_clk), .reset(gpif_rst), .clear(0),
       .datain(data_int), .src_rdy_i(src_rdy_int), .dst_rdy_o(dst_rdy_int), .space(),
-      .dataout(data_o), .src_rdy_o(final_rdy_data), .dst_rdy_i(send_data_line), .occupied());
+      .dataout(data_o), .src_rdy_o(final_rdy_data), .dst_rdy_i(consume_data_line), .occupied());
 
-   reg [7:0] 	packet_count;
    always @(negedge gpif_clk)
      if(gpif_rst)
        packet_count <= 0;
      else
-       if(src_rdy_int & dst_rdy_int & data_int[17]) // eop
-	 if(~(send_data_line & data_o[16]))
-	   packet_count <= packet_count + 1;
-	 else
-	   ;
-       else
-	 if(send_data_line & data_o[16])
-	   packet_count <= packet_count - 1;
+       if(produce_eop & ~consume_sop)
+	 packet_count <= packet_count + 1;
+       else if(consume_sop & ~produce_eop)
+	 packet_count <= packet_count - 1;
 
    always @(negedge gpif_clk)
      if(gpif_rst)
+       do_padding <= 0;
+     else if(~gpif_rd)
+       do_padding <= 0;
+     else if(consume_eop)
+       do_padding <= 1;   
+       
+   always @(negedge gpif_clk)
+     if(gpif_rst)
        gpif_empty_d <= 1;
      else
        gpif_empty_d <= ~|packet_count;
    	      
    // Response Path
    wire [15:0] 	resp_fifolevel;
-   wire 	send_resp_line = gpif_rd & gpif_ep & ~read_count[4];
+   wire 	consume_resp_line = gpif_rd & gpif_ep & ~read_count[4];
 
-   fifo_2clock_cascade #(.WIDTH(19), .SIZE(4)) resp_fifo_2clk
-     (.wclk(sys_clk), .datain(resp_i), .src_rdy_i(resp_src_rdy_i), .dst_rdy_o(resp_dst_rdy_o), .space(),
+   fifo_2clock_cascade #(.WIDTH(18), .SIZE(4)) resp_fifo_2clk
+     (.wclk(sys_clk), .datain(resp_i[17:0]), .src_rdy_i(resp_src_rdy_i), .dst_rdy_o(resp_dst_rdy_o), .space(),
       .rclk(~gpif_clk), .dataout(resp_o), 
-      .src_rdy_o(final_rdy_resp), .dst_rdy_i(send_resp_line), .occupied(resp_fifolevel),
+      .src_rdy_o(final_rdy_resp), .dst_rdy_i(consume_resp_line), .occupied(resp_fifolevel),
       .arst(sys_rst));
 
    // FIXME -- handle short packets
@@ -82,6 +89,6 @@ module gpif_rd
 
    assign debug = { { 16'd0 },
 		    { data_int[17:16], data_o[17:16], packet_count[3:0] },
-		    { 2'b0,final_rdy_data, final_rdy_resp, send_data_line, send_resp_line, src_rdy_int, dst_rdy_int} };
+		    { 2'b0,final_rdy_data, final_rdy_resp, consume_data_line, consume_resp_line, src_rdy_int, dst_rdy_int} };
    
 endmodule // gpif_rd