fix clear fifo on erroneous frame

hdl/ccn_pack.vhd

@@ -109,13 +109,16 @@ architecture rtl of ccn_pack is
 
     -- Output FIFO
     signal fifo_tvalid              : std_logic;
+    signal fifo_tvalid_c            : std_logic;
     signal fifo_tready              : std_logic;
+    signal fifo_tready_c            : std_logic;
     signal fifo_tdata               : std_logic_vector(63 downto 0);
     signal fifo_tkeep               : std_logic_vector(7 downto 0);
     signal fifo_tlast               : std_logic;
     signal fifo_tuser               : std_logic_vector(0 downto 0);
     signal fifo_tuser_slv           : std_logic_vector(7 downto 0);
     signal fifo_err_rst             : std_logic;
+    signal fifo_clr                 : std_logic;
 
     -- Some constant for mapping
     constant C_TKEEP_S00            : std_logic_vector(23 downto 0)              := (others => '1');
@@ -235,6 +238,23 @@ begin
         end if;
     end process p_frame_cnt;
 
+    ----------------
+    -- FIFO CLEAR --
+    ----------------
+    p_fifo_clr:process(aclk, aresetn)
+    begin
+        if aresetn = '0' then
+            fifo_clr  <= '0';
+        elsif rising_edge(aclk) then
+            if fifo_tuser(0) = '1' then
+                fifo_clr        <= '1';
+            else
+                if fifo_tlast = '1' then
+                    fifo_clr    <= '0';
+                end if;
+            end if;
+        end if;
+    end process p_fifo_clr;
 
     ----------------------
     -- HEADER INSERTION --
@@ -290,7 +310,7 @@ begin
         s01_axis_tlast       => pkt_ix_tlast,
         s01_axis_tuser       => pkt_ix_tuser,
         m00_axis_tvalid      => fifo_tvalid,
-        m00_axis_tready      => fifo_tready,
+        m00_axis_tready      => fifo_tready_c,
         m00_axis_tdata       => fifo_tdata,
         m00_axis_tkeep       => fifo_tkeep,
         m00_axis_tlast       => fifo_tlast,
@@ -303,14 +323,16 @@ begin
     -- FIFO --
     ----------
     fifo_tuser(0) <= or_reduce(fifo_tuser_slv);
-    fifo_err_rst  <= (not fifo_tuser(0)) and aresetn;
+    fifo_err_rst  <= (not fifo_clr) and aresetn;
+    fifo_tready_c <= fifo_tready or fifo_clr;
+    fifo_tvalid_c <= fifo_tvalid and not fifo_clr;
 
     inst_fifo: entity work.ccn_axis_fifo_pframe
     port map(
         s_axis_aresetn => fifo_err_rst,
         s_axis_aclk    => aclk,
         m_axis_aclk    => m_axis_clk,
-        s_axis_tvalid  => fifo_tvalid,
+        s_axis_tvalid  => fifo_tvalid_c,
         s_axis_tready  => fifo_tready,
         s_axis_tdata   => fifo_tdata,
         s_axis_tkeep   => fifo_tkeep,