eth: Clean up masking, lane 0 never needs to be masked

Signed-off-by: Alex Forencich <alex@alexforencich.com>

src/eth/rtl/taxi_axis_baser_tx_32.sv

@@ -298,7 +298,7 @@ endfunction
 wire [DATA_W-1:0] s_axis_tx_tdata_masked;
 
 for (genvar n = 0; n < KEEP_W; n = n + 1) begin
-    assign s_axis_tx_tdata_masked[n*8 +: 8] = s_axis_tx.tkeep[n] ? s_axis_tx.tdata[n*8 +: 8] : 8'd0;
+    assign s_axis_tx_tdata_masked[n*8 +: 8] = (n == 0 || s_axis_tx.tkeep[n]) ? s_axis_tx.tdata[n*8 +: 8] : 8'd0;
 end
 
 // FCS cycle calculation

src/eth/rtl/taxi_axis_baser_tx_64.sv

@@ -179,8 +179,6 @@ logic [31:0] swap_data = 32'd0;
 
 logic output_data_finish_reg = 1'b0;
 
-logic [DATA_W-1:0] s_axis_tx_tdata_masked;
-
 logic [DATA_W-1:0] s_tdata_reg = '0, s_tdata_next;
 logic [EMPTY_W-1:0] s_empty_reg = '0, s_empty_next;
 
@@ -314,10 +312,10 @@ function [2:0] keep2empty(input [7:0] k);
 endfunction
 
 // Mask input data
-always_comb begin
-    for (integer j = 0; j < 8; j = j + 1) begin
-        s_axis_tx_tdata_masked[j*8 +: 8] = s_axis_tx.tkeep[j] ? s_axis_tx.tdata[j*8 +: 8] : 8'd0;
-    end
+wire [DATA_W-1:0] s_axis_tx_tdata_masked;
+
+for (genvar n = 0; n < KEEP_W; n = n + 1) begin
+    assign s_axis_tx_tdata_masked[n*8 +: 8] = (n == 0 || s_axis_tx.tkeep[n]) ? s_axis_tx.tdata[n*8 +: 8] : 8'd0;
 end
 
 // FCS cycle calculation

src/eth/rtl/taxi_axis_xgmii_rx_32.sv

@@ -222,6 +222,15 @@ eth_crc (
     .state_out(crc_state_next)
 );
 
+// Mask input data
+wire [DATA_W-1:0] xgmii_rxd_masked;
+wire [CTRL_W-1:0] xgmii_term;
+
+for (genvar n = 0; n < CTRL_W; n = n + 1) begin
+    assign xgmii_rxd_masked[n*8 +: 8] = (n > 0 && xgmii_rxc[n]) ? 8'd0 : xgmii_rxd[n*8 +: 8];
+    assign xgmii_term[n] = xgmii_rxc[n] && (xgmii_rxd[n*8 +: 8] == XGMII_TERM);
+end
+
 always_comb begin
     state_next = STATE_IDLE;
 
@@ -529,7 +538,7 @@ always_ff @(posedge clk) begin
         framing_error_reg <= xgmii_rxc != 0;
 
         for (integer i = CTRL_W-1; i >= 0; i = i - 1) begin
-            if (xgmii_rxc[i] && (xgmii_rxd[i*8 +: 8] == XGMII_TERM)) begin
+            if (xgmii_term[i]) begin
                 term_present_reg <= 1'b1;
                 term_first_cycle_reg <= i == 0;
                 term_lane_reg <= 2'(i);
@@ -547,10 +556,8 @@ always_ff @(posedge clk) begin
 
         crc_valid_save <= crc_valid;
 
-        for (integer i = 0; i < CTRL_W; i = i + 1) begin
-            xgmii_rxd_d0[i*8 +: 8] <= xgmii_rxc[i] ? 8'd0 : xgmii_rxd[i*8 +: 8];
-        end
         xgmii_rxc_d0 <= xgmii_rxc;
+        xgmii_rxd_d0 <= xgmii_rxd_masked;
         xgmii_rxd_d1 <= xgmii_rxd_d0;
         xgmii_rxd_d2 <= xgmii_rxd_d1;
 

src/eth/rtl/taxi_axis_xgmii_rx_64.sv

@@ -239,7 +239,7 @@ wire [DATA_W-1:0] xgmii_rxd_masked;
 wire [CTRL_W-1:0] xgmii_term;
 
 for (genvar n = 0; n < CTRL_W; n = n + 1) begin
-    assign xgmii_rxd_masked[n*8 +: 8] = xgmii_rxc[n] ? 8'd0 : xgmii_rxd[n*8 +: 8];
+    assign xgmii_rxd_masked[n*8 +: 8] = (n > 0 && xgmii_rxc[n]) ? 8'd0 : xgmii_rxd[n*8 +: 8];
     assign xgmii_term[n] = xgmii_rxc[n] && (xgmii_rxd[n*8 +: 8] == XGMII_TERM);
 end
 
@@ -574,7 +574,7 @@ always_ff @(posedge clk) begin
             framing_error_reg <= xgmii_rxc != 0;
 
             for (integer i = CTRL_W-1; i >= 0; i = i - 1) begin
-                if (xgmii_rxc[i] && (xgmii_rxd[i*8 +: 8] == XGMII_TERM)) begin
+                if (xgmii_term[i]) begin
                     term_present_reg <= 1'b1;
                     term_first_cycle_reg <= i <= 4;
                     term_lane_reg <= 3'(i);

src/eth/rtl/taxi_axis_xgmii_tx_32.sv

@@ -246,8 +246,8 @@ endfunction
 // Mask input data
 wire [DATA_W-1:0] s_axis_tx_tdata_masked;
 
-for (genvar n = 0; n < CTRL_W; n = n + 1) begin
-    assign s_axis_tx_tdata_masked[n*8 +: 8] = s_axis_tx.tkeep[n] ? s_axis_tx.tdata[n*8 +: 8] : 8'd0;
+for (genvar n = 0; n < KEEP_W; n = n + 1) begin
+    assign s_axis_tx_tdata_masked[n*8 +: 8] = (n == 0 || s_axis_tx.tkeep[n]) ? s_axis_tx.tdata[n*8 +: 8] : 8'd0;
 end
 
 // FCS cycle calculation

src/eth/rtl/taxi_axis_xgmii_tx_64.sv

@@ -258,8 +258,8 @@ endfunction
 // Mask input data
 wire [DATA_W-1:0] s_axis_tx_tdata_masked;
 
-for (genvar n = 0; n < CTRL_W; n = n + 1) begin
-    assign s_axis_tx_tdata_masked[n*8 +: 8] = s_axis_tx.tkeep[n] ? s_axis_tx.tdata[n*8 +: 8] : 8'd0;
+for (genvar n = 0; n < KEEP_W; n = n + 1) begin
+    assign s_axis_tx_tdata_masked[n*8 +: 8] = (n == 0 || s_axis_tx.tkeep[n]) ? s_axis_tx.tdata[n*8 +: 8] : 8'd0;
 end
 
 // FCS cycle calculation