u1p: do padding outside of gpif_rd, in packet_splitter

1 files changed, 79 insertions, 0 deletions

diff --git a/usrp2/gpif/packet_splitter.v b/usrp2/gpif/packet_splitter.v
new file mode 100644
index 000000000..43515dd8b
--- /dev/null
+++ b/usrp2/gpif/packet_splitter.v
@@ -0,0 +1,79 @@
+
+// Split vita packets longer than one GPIF frame, add padding on short frames
+
+module packet_splitter
+  #(parameter FRAME_LEN=256)
+   (input clk, input reset, input clear,
+    input [18:0] data_i,
+    input src_rdy_i,
+    output dst_rdy_o,
+    output [18:0] data_o,
+    output src_rdy_o,
+    input dst_rdy_i);
+   
+   reg [1:0] state;
+   reg [15:0] length;
+   reg [15:0] frame_len;
+   
+   localparam PS_IDLE = 0;
+   localparam PS_FRAME = 1;
+   localparam PS_NEW_FRAME = 2;
+   localparam PS_PAD = 3;
+   
+   always @(posedge clk)
+     if(reset | clear)
+       state <= PS_IDLE;
+     else
+       case(state)
+	 PS_IDLE :
+	   if(src_rdy_i & dst_rdy_i)
+	     begin
+		length <= { data_i[14:0],1'b0};
+		frame_len <= FRAME_LEN;
+		state <= PS_FRAME;
+	     end
+	 PS_FRAME :
+	   if(src_rdy_i & dst_rdy_i)
+	     if(frame_len == 0)
+	       if(length == 0)
+		 state <= PS_IDLE;
+	       else
+		 begin
+		    state <= PS_NEW_FRAME;
+		    frame_len <= FRAME_LEN;
+		    length <= length - 1;
+		 end
+	     else
+	       if(length == 0)
+		 begin
+		    frame_len <= frame_len - 1;
+		    state <= PS_PAD;
+		 end
+	 PS_NEW_FRAME :
+	   if(src_rdy_i & dst_rdy_i)
+	     begin
+		frame_len <= frame_len - 1;
+		state <= PS_FRAME;
+	     end
+	 PS_PAD :
+	   if(dst_rdy_i)
+	     if(frame_len == 0)
+	       state <= PS_IDLE;
+	     else
+	       frame_len <= frame_len - 1;
+
+       endcase // case (state)
+   
+	
+   
+   assign dst_rdy_o = dst_rdy_i & (state != PS_PAD);
+   assign src_rdy_o = src_rdy_i | (state == PS_PAD);
+   
+   wire occ_out = 0;
+   wire eof_out = (frame_len == 0) & (state != PS_IDLE);
+   wire sof_out = (state == PS_IDLE) | (state == PS_NEW_FRAME);
+
+   wire [15:0] data_out = data_i[15:0];
+   assign data_o = {occ_out, eof_out, sof_out, data_out};
+   
+endmodule // packet_splitter