fpga: e320: Cleanup MTU parameters

Original-commit: a6a76002ead284815d9337e30c50f590466eb429

top/e320/e320.v

@@ -191,6 +191,9 @@ module e320 (
     CHDR_W_must_be_64_for_this_USRP();
   end
 
+  // Log base 2 of the maximum transmission unit (MTU) in bytes
+  localparam BYTE_MTU = $clog2(8192);
+
   `ifdef SFP_1GBE
     parameter PROTOCOL = "1GbE";
     parameter MDIO_EN = 1'b1;
@@ -1082,6 +1085,7 @@ module e320 (
     .PORTNUM(SFP_PORTNUM),
     .MDIO_EN(MDIO_EN),
     .MDIO_PHYADDR(MDIO_PHYADDR),
+    .BYTE_MTU(BYTE_MTU),
     .RFNOC_PROTOVER(RFNOC_PROTOVER),
     .NODE_INST(0)
   ) sfp_wrapper_i (
@@ -1322,6 +1326,7 @@ module e320 (
     .DWIDTH         (REG_DWIDTH),
     .AWIDTH         (REG_AWIDTH),
     .PORTNUM        (8'd1),
+    .BYTE_MTU       (BYTE_MTU),
     .RFNOC_PROTOVER (RFNOC_PROTOVER),
     .NODE_INST      (1)
   ) eth_internal_i (
@@ -1703,6 +1708,7 @@ module e320 (
     .FP_GPIO_WIDTH(FP_GPIO_WIDTH),
     .DB_GPIO_WIDTH(DB_GPIO_WIDTH),
     .CHDR_W(CHDR_W),
+    .BYTE_MTU(BYTE_MTU),
     .RFNOC_PROTOVER(RFNOC_PROTOVER)
   ) e320_core_i (
 

top/e320/e320_core.v

@@ -26,6 +26,7 @@ module e320_core #(
   parameter FP_GPIO_WIDTH = 8,  // Front panel GPIO width
   parameter DB_GPIO_WIDTH = 16,  // Daughterboard GPIO width
   parameter CHDR_W = 64,
+  parameter BYTE_MTU = $clog2(8192),
   parameter RFNOC_PROTOVER  = {8'd1, 8'd0}
 )(
   // Clocks and resets
@@ -1029,6 +1030,7 @@ module e320_core #(
 
   rfnoc_image_core #(
     .CHDR_W   (CHDR_W),
+    .MTU      (BYTE_MTU - $clog2(CHDR_W/8)),
     .PROTOVER (RFNOC_PROTOVER)
   ) rfnoc_sandbox_i (
     .chdr_aclk               (bus_clk    ),

top/e320/e320_sfp_wrapper.v

@@ -17,6 +17,7 @@
 //   PORTNUM          : Port number
 //   MDIO_EN          : Enables internal MDIO master
 //   MDIO_PHYADDR     : Address to use for the MDIO
+//   BYTE_MTU         : Log base 2 of the MTU in bytes
 //   RFNOC_PROTOVER   : RFNoC protocol version to be reported by transport
 //                      adapters.
 //   NODE_INST        : RFNoC transport adapter node instance for this port
@@ -34,6 +35,7 @@ module e320_sfp_wrapper #(
   parameter [7:0]  PORTNUM          = 8'd0,
   parameter        MDIO_EN          = 0,
   parameter [4:0]  MDIO_PHYADDR     = 5'd0,
+  parameter        BYTE_MTU         = $clog2(8192),
   parameter [15:0] RFNOC_PROTOVER   = {8'd1, 8'd0},
   parameter        NODE_INST        = 0,
   parameter        EN_RX_KV_MAP_CFG = 1,
@@ -302,6 +304,8 @@ module e320_sfp_wrapper #(
       if (EN_RX_KV_MAP_CFG || EN_RX_RAW_PYLD) begin : gen_eth_ipv4_interface_wrapper
         eth_ipv4_interface_wrapper #(
           .PROTOVER         (RFNOC_PROTOVER),
+          .CPU_FIFO_SIZE    (BYTE_MTU),
+          .CHDR_FIFO_SIZE   (BYTE_MTU),
           .NODE_INST        (NODE_INST),
           .REG_AWIDTH       (AWIDTH),
           .BASE             (REG_BASE_ETH_SWITCH),
@@ -361,7 +365,7 @@ module e320_sfp_wrapper #(
       else begin : gen_eth_interface
         eth_interface #(
           .PROTOVER   (RFNOC_PROTOVER),
-          .MTU        (10),
+          .MTU        (BYTE_MTU-3),        // Log base 2 of the MTU in 64-words
           .NODE_INST  (NODE_INST),
           .REG_AWIDTH (AWIDTH),
           .BASE       (REG_BASE_ETH_SWITCH)