ep_tx_vlan_unit: fix flush_ethertype handling added in dafd057e

Previous implementation caused dvalid=1 in Idle state too early in some cases (large traffic) so that the non-valid data word is validated.

ep_tx_vlan_unit: fix flush_ethertype handling added in dafd057e
Previous implementation caused dvalid=1 in Idle state too early in some cases (large traffic) so that the non-valid data word is validated.
7e59441f · Grzegorz Daniluk · 62324a27 · 7e59441f
Commit 7e59441f authored Feb 10, 2015 by Grzegorz Daniluk
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Showing with 24 additions and 9 deletions

ep_tx_vlan_unit.vhd modules/wr_endpoint/ep_tx_vlan_unit.vhd +24 -9

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--- a/modules/wr_endpoint/ep_tx_vlan_unit.vhd
+++ b/modules/wr_endpoint/ep_tx_vlan_unit.vhd
@@ -96,11 +96,12 @@ architecture behavioral of ep_tx_vlan_unit is

  signal vut_stored_tag       : std_logic_vector(15 downto 0);
  signal vut_stored_ethertype : std_logic_vector(15 downto 0);
+  signal flush_ethertype : std_logic;
+  signal flushed         : std_logic;

  signal mem_addr_muxed : std_logic_vector(9 downto 0);
  signal mem_rdata      : std_logic_vector(17 downto 0);
  signal src_dreq_d0    : std_logic;
-  signal flush_ethtype  : std_logic;

 begin  -- behavioral

@@ -145,19 +146,19 @@ begin  -- behavioral
    if rising_edge(clk_sys_i) then
      if rst_n_i = '0' then
        state <= IDLE;
-        flush_ethtype <= '0';
      else
        case state is
          when IDLE =>
-            if(src_dreq_i='1') then
-              flush_ethtype <= '0';
-            end if;
+            flushed <= '0';
            if(snk_fab_i.sof = '1') then
              counter <= (others => '0');
            end if;
            if(snk_fab_i.dvalid = '1' and snk_fab_i.addr = c_WRF_DATA and counter /= 6) then
              counter <= counter + 1;
            end if;
+            if(src_dreq_i='1') then
+              flush_ethertype <= '0';
+            end if;

            if(snk_fab_i.dvalid = '1' and counter = 5) then
              state <= CHECK_ETHERTYPE;
@@ -184,13 +185,23 @@ begin  -- behavioral
            end if;

          when POP_ETHERTYPE =>
-            flush_ethtype <= src_dreq_i;
            if(vut_untag = '1') then
              vut_untag_reg <= '1';
            end if;
            if(snk_fab_i.dvalid = '1') then
              vut_stored_ethertype <= snk_fab_i.data; 
            end if;
+            -- if dreq is '1' in POP_ETHERTYPE, that means we have passed
+            -- ethertype to src_fab_o and we don't need to do it after going to
+            -- IDLE.
+            if(src_dreq_d0 = '1') then
+              flush_ethertype <= '0';
+            elsif(src_dreq_i = '0' and flushed = '0') then
+              flush_ethertype <= '1';
+            end if;
+            if(src_dreq_d0 = '1') then
+              flushed <= '1';
+            end if;
            if( (vut_untag = '1' or vut_untag_reg = '1') and src_dreq_i = '1') then
              state <= IDLE; 
            end if;
@@ -215,7 +226,7 @@ begin  -- behavioral


 --   p_main_fsm_comb : process(snk_fab_i, src_dreq_d0, state, vut_stored_tag, vut_stored_ethertype, counter,vut_untag)
-  p_main_fsm_comb : process(snk_fab_i,src_dreq_i, src_dreq_d0, state, vut_stored_tag, vut_stored_ethertype, counter,vut_untag)
+  p_main_fsm_comb : process(snk_fab_i,src_dreq_i, src_dreq_d0, state, vut_stored_tag, vut_stored_ethertype, counter,vut_untag, flush_ethertype)
  begin

    case state is
@@ -235,9 +246,13 @@ begin  -- behavioral
      when IDLE =>
        snk_dreq_o       <= src_dreq_i;
        -- validate Ethertype from POP_ETHERTYPE state if dreq was high
-        src_fab_o.dvalid <= snk_fab_i.dvalid or (flush_ethtype and src_dreq_d0);
-        src_fab_o.data   <= snk_fab_i.data;
+        src_fab_o.dvalid <= snk_fab_i.dvalid or flush_ethertype;
        src_fab_o.addr   <= snk_fab_i.addr;
+        if(flush_ethertype = '1') then
+          src_fab_o.data   <= vut_stored_ethertype;
+        else
+          src_fab_o.data   <= snk_fab_i.data;
+        end if;

      when CHECK_ETHERTYPE =>
        snk_dreq_o <= src_dreq_i;