e100: switch to fixed length xfers

3 files changed, 34 insertions, 33 deletions

diff --git a/usrp2/gpmc/fifo_to_gpmc.v b/usrp2/gpmc/fifo_to_gpmc.v
index 26443a702..93341975d 100644
--- a/usrp2/gpmc/fifo_to_gpmc.v
+++ b/usrp2/gpmc/fifo_to_gpmc.v
@@ -46,7 +46,6 @@ module fifo_to_gpmc
    output reg data_available);
 
     //states for the GPMC side of things
-    wire [17:0] data_o;
     reg gpmc_state;
     reg [ADDR_WIDTH:1] addr;
     reg [PTR_WIDTH:0] gpmc_ptr, next_gpmc_ptr;
@@ -147,14 +146,11 @@ module fifo_to_gpmc
 
     assign dst_rdy_o = fifo_state == FIFO_STATE_FILL;
 
-    //assign data from bram output
-    assign EM_D = data_o[15:0];
-
     //instantiate dual ported bram for async read + write
-    ram_2port #(.DWIDTH(18),.AWIDTH(PTR_WIDTH + ADDR_WIDTH)) async_fifo_bram
+    ram_2port #(.DWIDTH(16),.AWIDTH(PTR_WIDTH + ADDR_WIDTH)) async_fifo_bram
      (.clka(clk),.ena(1'b1),.wea(src_rdy_i && dst_rdy_o),
-      .addra({fifo_ptr[PTR_WIDTH-1:0], counter}),.dia(data_i),.doa(),
+      .addra({fifo_ptr[PTR_WIDTH-1:0], counter}),.dia(data_i[15:0]),.doa(),
       .clkb(EM_CLK),.enb(1'b1),.web(1'b0),
-      .addrb({gpmc_ptr[PTR_WIDTH-1:0], addr}),.dib(18'h3ffff),.dob(data_o));
+      .addrb({gpmc_ptr[PTR_WIDTH-1:0], addr}),.dib(18'h3ffff),.dob(EM_D));
 
 endmodule // fifo_to_gpmc
diff --git a/usrp2/gpmc/gpmc.v b/usrp2/gpmc/gpmc.v
index 2ba69d184..2f22889cc 100644
--- a/usrp2/gpmc/gpmc.v
+++ b/usrp2/gpmc/gpmc.v
@@ -58,8 +58,8 @@ module gpmc
    wire [35:0] 	  txb_data;
    wire 	  txb_src_rdy, txb_dst_rdy;
 
-   gpmc_to_fifo #(.ADDR_WIDTH(ADDR_WIDTH)) gpmc_to_fifo
-     (.EM_D(EM_D), .EM_A(EM_A), .EM_CLK(EM_CLK), .EM_WE(~EM_NCS4 & ~EM_NWE),
+   gpmc_to_fifo #(.ADDR_WIDTH(10), .LAST_ADDR(10'h3ff), .PTR_WIDTH(2)) gpmc_to_fifo
+     (.EM_D(EM_D), .EM_A(EM_A[10:1]), .EM_CLK(EM_CLK), .EM_WE(~EM_NCS4 & ~EM_NWE),
       .clk(fifo_clk), .reset(fifo_rst), .clear(1'b0), .arst(fifo_rst | arst),
       .data_o(tx18_data), .src_rdy_o(tx18_src_rdy), .dst_rdy_i(tx18_dst_rdy),
       .have_space(tx_have_space));
@@ -112,8 +112,8 @@ module gpmc
    wire [35:0] 	  ctrlb_data;
    wire 	  ctrlb_src_rdy, ctrlb_dst_rdy;
 
-   gpmc_to_fifo #(.PTR_WIDTH(5), .ADDR_WIDTH(5)) ctrl_gpmc_to_fifo
-     (.EM_D(EM_D), .EM_A(EM_A[5:1]), .EM_CLK(EM_CLK), .EM_WE(~EM_NCS6 & ~EM_NWE & (EM_A[ADDR_WIDTH:6] == 0)),
+   gpmc_to_fifo #(.PTR_WIDTH(5), .ADDR_WIDTH(5), .LAST_ADDR(5'h0f)) ctrl_gpmc_to_fifo
+     (.EM_D(EM_D), .EM_A(EM_A[5:1]), .EM_CLK(EM_CLK), .EM_WE(~EM_NCS6 & ~EM_NWE),
       .clk(fifo_clk), .reset(fifo_rst), .clear(1'b0), .arst(fifo_rst | arst),
       .data_o(ctrl18_data), .src_rdy_o(ctrl18_src_rdy), .dst_rdy_i(ctrl18_dst_rdy),
       .have_space(/*always*/));
@@ -149,12 +149,12 @@ module gpmc
       .f36_datain(respb_data), .f36_src_rdy_i(respb_src_rdy), .f36_dst_rdy_o(respb_dst_rdy),
       .f19_dataout({resp_dummy,resp18_data}), .f19_src_rdy_o(resp18_src_rdy), .f19_dst_rdy_i(resp18_dst_rdy) );
 
-   fifo_to_gpmc #(.ADDR_WIDTH(ADDR_WIDTH), .LAST_ADDR(10'h00f)) resp_fifo_to_gpmc
+   fifo_to_gpmc #(.PTR_WIDTH(5), .ADDR_WIDTH(5), .LAST_ADDR(5'h0f)) resp_fifo_to_gpmc
      (.clk(fifo_clk), .reset(fifo_rst), .clear(1'b0), .arst(fifo_rst | arst),
       .data_i(resp18_data), .src_rdy_i(resp18_src_rdy), .dst_rdy_o(resp18_dst_rdy),
-      .EM_D(EM_D_ctrl), .EM_A(EM_A), .EM_CLK(EM_CLK), .EM_OE(~EM_NCS6 & ~EM_NOE),
+      .EM_D(EM_D_ctrl), .EM_A(EM_A[5:1]), .EM_CLK(EM_CLK), .EM_OE(~EM_NCS6 & ~EM_NOE),
       .data_available(resp_have_data));
-
+//*
     assign debug = {
         EM_D,
         //resp18_data[15:0], //16
@@ -163,5 +163,5 @@ module gpmc
         EM_NCS4, EM_NCS6, EM_NWE, EM_NOE, //4
         EM_CLK, resp_have_data //2
     };
-
+//*/
 endmodule // gpmc
diff --git a/usrp2/gpmc/gpmc_to_fifo.v b/usrp2/gpmc/gpmc_to_fifo.v
index 3932b81ac..d1897faec 100644
--- a/usrp2/gpmc/gpmc_to_fifo.v
+++ b/usrp2/gpmc/gpmc_to_fifo.v
@@ -36,18 +36,15 @@
 ////////////////////////////////////////////////////////////////////////
 
 module gpmc_to_fifo
-  #(parameter PTR_WIDTH = 2, parameter ADDR_WIDTH = 10, parameter XFER_OFFSET = 2)
+  #(parameter PTR_WIDTH = 2, parameter ADDR_WIDTH = 10, parameter LAST_ADDR = 10'h3ff)
   (input [15:0] EM_D, input [ADDR_WIDTH:1] EM_A, input EM_CLK, input EM_WE,
    input clk, input reset, input clear, input arst,
    output [17:0] data_o, output src_rdy_o, input dst_rdy_i,
    output reg have_space);
 
     //states for the GPMC side of things
-    wire [17:0] data_i;
     reg gpmc_state;
-    reg [15:0] vita_len;
     reg [ADDR_WIDTH:1] addr;
-    wire [ADDR_WIDTH:1] last_addr = {vita_len[ADDR_WIDTH-2:0], 1'b0} - 1'b1 + XFER_OFFSET;
     reg [PTR_WIDTH:0] gpmc_ptr, next_gpmc_ptr;
     localparam GPMC_STATE_START = 0;
     localparam GPMC_STATE_FILL = 1;
@@ -55,6 +52,8 @@ module gpmc_to_fifo
     //states for the FIFO side of things
     reg [1:0] fifo_state;
     reg [ADDR_WIDTH-1:0] counter;
+    reg [ADDR_WIDTH-1:0] last_counter;
+    reg [ADDR_WIDTH-1:0] last_xfer;
     reg [PTR_WIDTH:0] fifo_ptr;
     localparam FIFO_STATE_CLAIM = 0;
     localparam FIFO_STATE_EMPTY = 1;
@@ -75,15 +74,14 @@ module gpmc_to_fifo
             case(gpmc_state)
 
             GPMC_STATE_START: begin
-                if (data_i[16]) begin
+                if (EM_A == 0) begin
                     gpmc_state <= GPMC_STATE_FILL;
-                    vita_len <= EM_D;
                     next_gpmc_ptr <= gpmc_ptr + 1;
                 end
             end
 
             GPMC_STATE_FILL: begin
-                if (data_i[17]) begin
+                if (addr == LAST_ADDR) begin
                     gpmc_state <= GPMC_STATE_START;
                     gpmc_ptr <= next_gpmc_ptr;
                     addr <= 0;
@@ -123,14 +121,14 @@ module gpmc_to_fifo
         if (reset | clear) begin
             fifo_state <= FIFO_STATE_CLAIM;
             fifo_ptr <= 0;
-            counter <= XFER_OFFSET;
+            counter <= 0;
         end
         else begin
             case(fifo_state)
 
             FIFO_STATE_CLAIM: begin
                 if (bram_available_to_empty && data_o[16]) fifo_state <= FIFO_STATE_PRE;
-                counter <= XFER_OFFSET;
+                counter <= 0;
             end
 
             FIFO_STATE_PRE: begin
@@ -142,7 +140,7 @@ module gpmc_to_fifo
                 if (src_rdy_o && dst_rdy_i && data_o[17]) begin
                     fifo_state <= FIFO_STATE_CLAIM;
                     fifo_ptr <= fifo_ptr + 1;
-                    counter <= XFER_OFFSET;
+                    counter <= 0;
                 end
                 else if (src_rdy_o && dst_rdy_i) begin
                     counter <= counter + 1;
@@ -157,16 +155,23 @@ module gpmc_to_fifo
 
     assign src_rdy_o = fifo_state == FIFO_STATE_EMPTY;
 
-    //assign data and frame bits to bram input
-    assign data_i[15:0] = EM_D;
-    assign data_i[16] = (addr == XFER_OFFSET);
-    assign data_i[17] = (addr == last_addr);
-
     //instantiate dual ported bram for async read + write
-    ram_2port #(.DWIDTH(18),.AWIDTH(PTR_WIDTH + ADDR_WIDTH)) async_fifo_bram
+    ram_2port #(.DWIDTH(16),.AWIDTH(PTR_WIDTH + ADDR_WIDTH)) async_fifo_bram
      (.clka(~EM_CLK),.ena(1'b1),.wea(EM_WE),
-      .addra({gpmc_ptr[PTR_WIDTH-1:0], addr}),.dia(data_i),.doa(),
+      .addra({gpmc_ptr[PTR_WIDTH-1:0], addr}),.dia(EM_D),.doa(),
       .clkb(clk),.enb(enable),.web(1'b0),
-      .addrb({fifo_ptr[PTR_WIDTH-1:0], counter}),.dib(18'h3ffff),.dob(data_o));
+      .addrb({fifo_ptr[PTR_WIDTH-1:0], counter}),.dib(18'h3ffff),.dob(data_o[15:0]));
+
+    //store the vita length -> last xfer count
+    always @(posedge clk) begin
+        if (src_rdy_o && dst_rdy_i && data_o[16]) begin
+            last_xfer <= {data_o[ADDR_WIDTH-2:0], 1'b0};
+        end
+    end
+
+    //logic for start and end of frame
+    always @(posedge clk) if (enable) last_counter <= counter;
+    assign data_o[17] = !data_o[16] && ((last_counter + 1'b1) == last_xfer);
+    assign data_o[16] = last_counter == 0;
 
 endmodule // gpmc_to_fifo