mux multiple fifo streams into one. Allows priority or round robin

1 files changed, 57 insertions, 0 deletions

diff --git a/usrp2/fifo/fifo36_mux.v b/usrp2/fifo/fifo36_mux.v
new file mode 100644
index 000000000..04ec5abe8
--- /dev/null
+++ b/usrp2/fifo/fifo36_mux.v
@@ -0,0 +1,57 @@
+
+// Mux packets from multiple FIFO interfaces onto a single one.
+//  Can alternate or give priority to one port (port 0)
+//  In prio mode, port 1 will never get access if port 0 is always busy
+
+module fifo36_mux
+  #(parameter prio = 0)
+   (input clk, input reset, input clear,
+    input [35:0] data0_i, input src0_rdy_i, output dst0_rdy_o,
+    input [35:0] data1_i, input src1_rdy_i, output dst1_rdy_o,
+    output [35:0] data_o, output src_rdy_o, input dst_rdy_i);
+
+   localparam MUX_IDLE0 = 0;
+   localparam MUX_DATA0 = 1;
+   localparam MUX_IDLE1 = 2;
+   localparam MUX_DATA1 = 3;
+   
+   reg [1:0] 	  state;
+
+   wire 	  eof0 = data0_i[33];
+   wire 	  eof1 = data1_i[33];
+   
+   always @(posedge clk)
+     if(reset | clear)
+       state <= MUX_IDLE0;
+     else
+       case(state)
+	 MUX_IDLE0 :
+	   if(src0_rdy_i)
+	     state <= MUX_DATA0;
+	   else if(src1_rdy_i)
+	     state <= MUX_DATA1;
+
+	 MUX_DATA0 :
+	   if(src0_rdy_i & dst_rdy_i & eof0)
+	     state <= prio ? MUX_IDLE0 : MUX_IDLE1;
+
+	 MUX_IDLE1 :
+	   if(src1_rdy_i)
+	     state <= MUX_DATA1;
+	   else if(src0_rdy_i)
+	     state <= MUX_DATA0;
+	   
+	 MUX_DATA1 :
+	   if(src1_rdy_i & dst_rdy_i & eof1)
+	     state <= MUX_IDLE0;
+	 
+	 default :
+	   state <= MUX_IDLE0;
+       endcase // case (state)
+
+   assign dst0_rdy_o = (state==MUX_DATA0) ? dst_rdy_i : 0;
+   assign dst1_rdy_o = (state==MUX_DATA1) ? dst_rdy_i : 0;
+   assign src_rdy_o = (state==MUX_DATA0) ? src0_rdy_i : (state==MUX_DATA1) ? src1_rdy_i : 0;
+   assign data_0 = (state==MUX_DATA0) ? data0_i : data1_i;
+   
+endmodule // fifo36_demux