Register ctlr_wr_flush_en to ease timing closure.

libraries/io/ddr/src/vhdl/io_ddr_driver_flush_ctrl.vhd

@@ -78,6 +78,8 @@ ARCHITECTURE str OF io_ddr_driver_flush_ctrl IS
   
   SIGNAL flush_dis : STD_LOGIC;
   
+  SIGNAL nxt_ctlr_wr_flush_en : STD_LOGIC;
+
 BEGIN
 
   -- Flush disable control
@@ -98,30 +100,33 @@ BEGIN
   p_reg : PROCESS(rst, clk)
   BEGIN
     IF rst='1' THEN
-      state <= s_flush;           -- default start in flush mode after power up
+      state            <= s_flush;           -- default start in flush mode after power up,
+      ctlr_wr_flush_en <= '1';               -- so default write flush is enabled
     ELSIF rising_edge(clk) THEN
       state            <= nxt_state;
+      ctlr_wr_flush_en <= nxt_ctlr_wr_flush_en;
     END IF;
   END PROCESS;
   
   p_state : PROCESS(state, dvr_wr_flush_en, dvr_done, dvr_en, dvr_wr_not_rd, flush_dis)
   BEGIN
     nxt_state <= state;
-    ctlr_wr_flush_en <= '0';
+    nxt_ctlr_wr_flush_en <= '0';
     CASE state IS
       WHEN s_idle => 
         IF dvr_wr_flush_en='1' AND dvr_done='1' THEN
-          ctlr_wr_flush_en <= '1';
+          nxt_ctlr_wr_flush_en <= '1';
           nxt_state <= s_flush;
         END IF;
       WHEN s_flush =>
-        ctlr_wr_flush_en <= '1';
+        nxt_ctlr_wr_flush_en <= '1';
         IF dvr_en='1' AND dvr_wr_not_rd='1' THEN
           nxt_state <= s_stop;
         END IF;
       WHEN OTHERS => -- s_stop
-        ctlr_wr_flush_en <= '1';
-        IF flush_dis = '1' THEN
+        nxt_ctlr_wr_flush_en <= '1';
+        IF flush_dis = '1' THEN             -- flush_dis comes from sosi control (valid, sop or sync) from look ahead (RL=0) write FIFO
+          nxt_ctlr_wr_flush_en <= '0';
           nxt_state <= s_idle;
         END IF;
     END CASE;