Squashed B200 FPGA Source. Code from Josh Blum, Ian Buckley, and Matt Ettus.

1 files changed, 123 insertions, 0 deletions

diff --git a/fpga/usrp2/gpif/packet_splitter.v b/fpga/usrp2/gpif/packet_splitter.v
new file mode 100644
index 000000000..ba4c8cded
--- /dev/null
+++ b/fpga/usrp2/gpif/packet_splitter.v
@@ -0,0 +1,123 @@
+//
+// Copyright 2011 Ettus Research LLC
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+//
+
+
+// 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  [7:0] frames_per_packet,
+    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,
+    output [31:0] debug0,
+    output [31:0] debug1);
+   
+   reg [1:0] state;
+   reg [15:0] length;
+   reg [15:0] frame_len;
+   reg [7:0]  frame_count;
+   
+   localparam PS_IDLE = 0;
+   localparam PS_FRAME = 1;
+   localparam PS_NEW_FRAME = 2;
+   localparam PS_PAD = 3;
+
+   wire       eof_i = data_i[17];
+   
+   always @(posedge clk)
+     if(reset | clear)
+       begin
+	  state <= PS_IDLE;
+	  frame_count <= 0;
+       end
+     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;
+		frame_count <= 1;
+	     end
+	 PS_FRAME :
+	   if(src_rdy_i & dst_rdy_i)
+	     if((frame_len == 2) & ((length == 2) | eof_i))
+	       state <= PS_IDLE;
+	     else if(frame_len == 2)
+	       begin
+		  length <= length - 1;
+		  state <= PS_NEW_FRAME;
+		  frame_count <= frame_count + 1;
+	       end
+	     else if((length == 2)|eof_i)
+	       begin
+		  frame_len <= frame_len - 1;
+		  state <= PS_PAD;
+	       end
+	     else
+	       begin
+		  frame_len <= frame_len - 1;
+		  length <= length - 1;
+	       end
+	 PS_NEW_FRAME :
+	   if(src_rdy_i & dst_rdy_i)
+	     begin
+		frame_len <= FRAME_LEN;
+		if((length == 2)|eof_i)
+		  state <= PS_PAD;
+		else
+		  begin
+		     state <= PS_FRAME;
+		     length <= length - 1;
+		  end // else: !if((length == 2)|eof_i)
+	     end // if (src_rdy_i & dst_rdy_i)
+	 
+	 PS_PAD :
+	   if(dst_rdy_i)
+	     if(frame_len == 2)
+	       state <= PS_IDLE;
+	     else
+	       frame_len <= frame_len - 1;
+
+       endcase // case (state)
+
+   wire next_state_is_idle = dst_rdy_i & (frame_len==2) & 
+	( (state==PS_PAD) | ( (state==PS_FRAME) & src_rdy_i & ((length==2)|eof_i) ) );
+	  
+	 
+	
+   
+   assign dst_rdy_o = dst_rdy_i & (state != PS_PAD);
+   assign src_rdy_o = src_rdy_i | (state == PS_PAD);
+   
+   wire eof_out = (frame_len == 2) & (state != PS_IDLE) & (state != PS_NEW_FRAME);
+   wire sof_out = (state == PS_IDLE) | (state == PS_NEW_FRAME);
+   wire occ_out = eof_out & next_state_is_idle & (frames_per_packet != frame_count);
+   
+   wire [15:0] data_out = data_i[15:0];
+   assign data_o = {occ_out, eof_out, sof_out, data_out};
+   
+   assign debug0 = { 8'd0, dst_rdy_o, src_rdy_o, next_state_is_idle, eof_out, sof_out, occ_out, state[1:0], frame_count[7:0], frames_per_packet[7:0] };
+   assign debug1 = { length[15:0], frame_len[15:0] };
+   
+endmodule // packet_splitter