added valid_arp signal

libraries/io/nw_10GbE/src/vhdl/nw_arp_request.vhd

@@ -75,6 +75,7 @@ ARCHITECTURE rtl of nw_arp_request IS
   CONSTANT c_dp_field_blk_snk_data_w : NATURAL := field_slv_len(c_hdr_field_arr);
   CONSTANT c_dp_field_blk_src_data_w : NATURAL := c_data_w;
 
+  SIGNAL valid_arp : STD_LOGIC := '0';
   SIGNAL pps_cnt   : NATURAL   := 0;
   SIGNAL trigger   : BOOLEAN   := FALSE;
 
@@ -101,11 +102,14 @@ BEGIN
   p_dp_pps : PROCESS (dp_clk, dp_rst)
   BEGIN
     IF dp_rst = '1' THEN
+      valid_arp <= '0';
       trigger <= FALSE;
       pps_cnt <= 0;
       dp_field_blk_snk_in <= c_dp_sosi_rst;
     ELSIF RISING_EDGE(dp_clk) THEN
-
+      -- Use signal to indicate if ARP can be enabled.
+      valid_arp <= vector_or(arp_sha) AND vector_or(arp_spa) AND vector_or(arp_tpa);
+      IF valid_arp = '1' THEN
         dp_field_blk_snk_in <= nxt_dp_field_blk_snk_in;
         IF trigger AND dp_field_blk_snk_out.ready = '1' AND dp_field_blk_snk_out.xon = '1' THEN
           trigger <= FALSE;
@@ -122,7 +126,11 @@ BEGIN
             trigger <= TRUE;
           END IF;
         END IF;
-
+      ELSE
+        trigger <= FALSE;
+        pps_cnt <= 0;
+        dp_field_blk_snk_in <= c_dp_sosi_rst;
+      END IF;
     END IF;
   END PROCESS;