swcore: added pck dropping (@RTU decision) in the input block

332b8403 · Maciej Lipinski · b488795e · 332b8403
Commit 332b8403 authored Jan 23, 2012 by Maciej Lipinski
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Showing with 71 additions and 13 deletions

xswc_input_block.vhd modules/wrsw_swcore/xswc_input_block.vhd +71 -13

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--- a/modules/wrsw_swcore/xswc_input_block.vhd
+++ b/modules/wrsw_swcore/xswc_input_block.vhd
@@ -212,6 +212,7 @@ architecture syn of xswc_input_block is

  signal read_mask   : std_logic_vector(c_swc_num_ports - 1 downto 0);
  signal read_prio   : std_logic_vector(c_swc_prio_width - 1 downto 0);
+  signal read_drop   : std_logic;
  signal read_usecnt : std_logic_vector(c_swc_usecount_width - 1 downto 0);

  signal write_mask   : std_logic_vector(c_swc_num_ports - 1 downto 0);
@@ -244,7 +245,8 @@ architecture syn of xswc_input_block is
                       S_INTERPCK_PAGE_REQ);    -- allocating in advance page to be used by 
                                                -- all but first page of the pck

-type t_write_state is (S_IDLE,               
+type t_write_state is (S_IDLE,  
+                       S_DROP_PCK,             
                       S_START_FIFO_RD,         -- start requesting data from FIFO, but still
                                                -- not outputing to write_pump (initial cycle)
                                                -- trick: drdy restricted only to S_WRITE_MPM
@@ -402,7 +404,9 @@ begin  --arch
  write_ctrl     <= fifo_data_out(c_swc_data_width + c_swc_ctrl_width - 1 downto c_swc_data_width);

  fifo_rd        <= ((not fifo_empty) and (not mpm_full_i)) when (write_state = S_WRITE_MPM or
-                                                                  write_state = S_START_FIFO_RD) else '0';
+                                                                  write_state = S_START_FIFO_RD)    else
+                     '1'                                    when (write_state = S_DROP_PCK)             else 
+                     '0';


  fifo_populated_enough <= '1' when
@@ -649,9 +653,52 @@ begin  --arch
               (rcv_rtu_state = S_RTU_DECISION_AVAILABLE) and   -- there is RTU decision avaible (TODO: *)
               (mpm_full_i = '0'                        )) then -- obvious, no write to full MPM

-              write_state <= S_START_FIFO_RD;
+               if(read_drop = '1' or read_mask = zeros(c_swc_num_ports - 1 downto 0)) then
+                 
+                 --droping pcks
+                 --
+                  write_state <= S_DROP_PCK;
+                  rtu_data_read_by_write_process <= '1';
+
+               else
+                  write_state <= S_START_FIFO_RD;
+               end if;
              
            end if;
+          --========================================================================================       
+          when S_DROP_PCK =>
+            --========================================================================================
+
+            rtu_data_read_by_write_process <= '0';
+            ------------------------------------------------------------------------------------------          
+            if(tx_rerror      = '1'     or   -- handling error, this signal is generated by read_fsm
+               write_ctrl_out = b"10") then  -- should not use this (this should be indicated previously
+                                             -- by tx_rerror
+              ------------------------------------------------------------------------------------------          
+              write_state                  <= S_IDLE;
+              
+            ------------------------------------------------------------------------------------------  
+            elsif(write_ctrl_out /= b"01" and  -- the data coming from FIFO indicates its not the first 
+                                               -- word of PCK *and*
+                  mpm_pckstart = '1') then     -- we are saying to MPM it's first word of PCK
+              ------------------------------------------------------------------------------------------  
+
+              -- this is pathologic situation, bad, not sure what to do
+              assert false
+                report "write_fsm: S_WRITE_MPM, should not go here";
+              
+            ------------------------------------------------------------------------------------------ 
+            else                        -- in normal case, we end up here
+              ------------------------------------------------------------------------------------------ 
+
+              if(write_ctrl_out = b"11") then  -- EOF without valid data -
+                write_state <= S_LAST_MPM_WR;
+              end if;
+            ------------------------------------------------------------------------------------------  
+            end if;
+
+
+
          -- TODO* enable to write to MPM even without RTU decision (will be quite some work)
          -- for the time being wait for RTU here
          --========================================================================================       
@@ -809,18 +856,27 @@ begin  --arch
               (rcv_rtu_state = S_RTU_DECISION_AVAILABLE) and   -- there is RTU decision avaible (TODO: !!!)
               (mpm_full_i = '0'                        )) then -- obvious, no write to full MPM

-              -- first word of the pck
-              current_pckstart_pageaddr <= pckstart_pageaddr;
-              write_mask                <= read_mask;
-              write_prio                <= read_prio;
-              write_usecnt              <= read_usecnt;
-              rtu_data_read_by_write_process <= '1';
+               if(read_drop = '1' or read_mask = zeros(c_swc_num_ports - 1 downto 0)) then
+
+                  --droping pcks
+                  write_state <= S_DROP_PCK;
+                  rtu_data_read_by_write_process <= '1';

-              mpm_pckstart <= '1';
-              mpm_pagereq  <= '1';
-              mpm_pageaddr <= pckstart_pageaddr;
+               else

-              write_state <= S_WRITE_MPM;
+                  -- first word of the pck
+                  current_pckstart_pageaddr <= pckstart_pageaddr;
+                  write_mask                <= read_mask;
+                  write_prio                <= read_prio;
+                  write_usecnt              <= read_usecnt;
+                  rtu_data_read_by_write_process <= '1';
+
+                  mpm_pckstart <= '1';
+                  mpm_pagereq  <= '1';
+                  mpm_pageaddr <= pckstart_pageaddr;
+    
+                  write_state <= S_WRITE_MPM;
+               end if;
              
            end if;

@@ -1090,6 +1146,7 @@ begin  --arch
        read_mask      <= (others => '0');
        read_prio      <= (others => '0');
        read_usecnt    <= (others => '0');
+        read_drop      <= '0';
        rtu_rsp_ack    <= '0';
      --========================================
      else
@@ -1105,6 +1162,7 @@ begin  --arch

                read_mask     <= rtu_dst_port_mask_i;
                read_prio     <= rtu_prio_i;
+		read_drop     <= rtu_drop_i;
                read_usecnt   <= std_logic_vector(to_signed(cnt(rtu_dst_port_mask_i), read_usecnt'length));
                rcv_rtu_state <= S_RTU_DECISION_AVAILABLE;
                rtu_rsp_ack   <= '1';