[swcore/in_blk] changed handling of nomem (memory full)

Now, we dump the frame if it has been already transfered - this is because if we pause waiting for the memory to get free... we create a who for the output (tx) which is bad for PCS....
If the frame has not been yet transfered, we can wait for RTU decision

Not sure this is the best solution

ALso, I added handling of the almost-impossible situation when we get the nonmem when we are in the cycle to decide whether to transfer or not... nusty

modules/wrsw_swcore/xswc_input_block.vhd

@@ -539,6 +539,14 @@ architecture syn of xswc_input_block is
   signal linkl_FSM : std_logic_vector(3  downto 0);
   
   signal zeros    : std_logic_vector(g_num_ports - 1 downto 0);
+  
+  constant c_wrf_status_error : t_wrf_status_reg := (
+        '0', -- is_hp
+        '0', -- has_smac
+        '0', -- has_crc
+        '1', -- error
+        '0', -- tag_me
+       x"00");-- match_class
   -------------------------------------------------------------------------------
   -- Function which calculates number of 1's in a vector
   ------------------------------------------------------------------------------- 
@@ -633,9 +641,18 @@ constant c_force_usecnt             : boolean :=  TRUE;
   -- (unless we needed to wait for RTU's decision to the end of reception) so we drop the frame
   -- if the resoruce is almost full
   signal res_info_almsot_full       : std_logic;
+  signal cur_res_info_almsot_full   : std_logic;
   
   -- a currently requested resource is full
   signal res_info_full              : std_logic;
+  signal cur_res_info_full          : std_logic;
+  signal mem_full_dump              : std_logic;
+  
+  -- synchronizing 4 FSMs to work together is not easy....:
+  signal tp_transfer_ready          : std_logic;
+  signal tp_transfer_rtu_valid      : std_logic;
+  signal tp_transfer_wait_sof       : std_logic;
+  signal tp_transfer_set_usecnt     : std_logic;
   
   signal dbg_dropped_on_res_full    : std_logic;
 
@@ -677,13 +694,29 @@ begin  --archS_PCKSTART_SET_AND_REQ
   in_pck_eof <= in_pck_eof_normal or in_pck_eof_on_pause;
 
   -- detecting error 
-  in_pck_err <= '1' when in_pck_dvalid = '1' and
-                   (snk_adr_int = c_WRF_STATUS) and
-                   (f_unmarshall_wrf_status(snk_dat_int).error = '1') else
+  in_pck_err <= '1' when  in_pck_dvalid = '1' and
+                         (snk_adr_int = c_WRF_STATUS) and
+                          (f_unmarshall_wrf_status(snk_dat_int).error = '1') else
+                '0';
+               
+  -- this indicates that a memory-full happens when the frame has been already tranfsered
+  -- to output (probably already being send out...) so we need to handled this properly, i.e.:
+  -- * write to MPM error status for the output
+  -- * stop receving    
+  mem_full_dump <= '1' when (lw_sync_2nd_stage_chk = '1' and 
+                             lw_sync_second_stage  = '0' and
+                             (mmu_nomem_i = '1' or cur_res_info_full = '1') and
+                            tp_transfer_valid = '1') else 
                    '0';
-
+--   -- this indicates that frame has not been yet transfered, we are lucky, we can 
+--   -- just drop receving the frame with no extra magic                   
+--   mem_full_drop <= '1' when (lw_sync_2nd_stage_chk = '1' and 
+--                              lw_sync_second_stage  = '0' and
+--                              (mmu_nomem_i = '1' or cur_res_info_full = '1') and
+--                             tp_transfer_valid = '1') else 
+--                    '0';
   -- to simplify stuff:
-  finish_rcv_pck <= '1' when (in_pck_eof = '1' or in_pck_err = '1' or tp_drop = '1') else '0';
+  finish_rcv_pck <= '1' when (in_pck_eof = '1' or in_pck_err = '1' or tp_drop = '1' or mem_full_dump ='1') else '0';
   --==================================================================================================
   -- FSM to receive pcks, it translates pWB I/F into MPM I/F
   --==================================================================================================
@@ -868,9 +901,21 @@ begin  --archS_PCKSTART_SET_AND_REQ
               rp_in_pck_err   <= '1';
               mpm_dvalid      <= '1';
               mpm_data        <= in_pck_dat;                
-            -- write to MPM data only if you know two consequtive WB writes, this is to detect EOF and
-            -- set HIGH dlast at an appropriate time
+            elsif(mem_full_dump = '1')then
+              -- this is an exceptional situatio when
+              -- 1) we've already transfered RTU decision (so output is tx-ing) AND
+              -- 2) memory is full, so we cannot store the rx-ed frame          AND
+              -- 3) we cannot pause, if we do, we will create holse on the output
+              -- so we dump the frame, by writing to memory error status (so tx will dump) and
+              -- we stop rx-ing
+              -- We set rp_in_pck_err so it is handled in the next cycle as error
+--               rp_in_pck_err   <= '1';
+              mpm_dvalid      <= '1';
+              mpm_data        <= c_WRF_STATUS & -- generate error msg for out_block                          
+                                 f_marshall_wrf_status(c_wrf_status_error); 
             elsif((in_pck_dvalid = '1' and in_pck_dvalid_d0 = '1') or finish_rcv_pck = '1') then
+              -- write to MPM data only if you know two consequtive WB writes, this is to detect EOF and
+              -- set HIGH dlast at an appropriate time
               mpm_dvalid <= '1';
               mpm_data   <= in_pck_dat_d0;
 
@@ -915,7 +960,7 @@ begin  --archS_PCKSTART_SET_AND_REQ
               -- decision from RTU to drop, PCK has not been transfered at all, so we need 
               -- to handle freeing. we also need to receive the rest of the pck
               -- TODO(1.0): throw error????
-            elsif(tp_drop = '1') then
+            elsif(tp_drop = '1' ) then
               
               mmu_force_free_addr <= current_pckstart_pageaddr;
 
@@ -950,9 +995,16 @@ begin  --archS_PCKSTART_SET_AND_REQ
               -- sync with (expliclitely) with ll_write and (implicitely) with transfer_pck 
               -- (transfer waits for  first page to be cleared (which is condition of sync_2nd_stage, 
             elsif(lw_sync_2nd_stage_chk = '1' and lw_sync_second_stage = '0') then
-              
-              snk_stall_force_h <= '1';
-              s_rcv_pck         <= S_PAUSE;
+             
+              if(mem_full_dump ='1') then 
+                -- stay in the the same state, we already set rp_in_pck_err and the problem
+                -- will be handled in the next cycle as error
+                s_rcv_pck         <= S_DROP;
+              else
+                -- hopefully will not happen
+                snk_stall_force_h <= '1';
+                s_rcv_pck         <= S_PAUSE;
+              end if;
 
             end if;
 
@@ -2066,10 +2118,50 @@ tp_drop <= '1' when ((s_transfer_pck = S_DROP) or
                                   ((current_drop = '1' or current_mask = zeros) and rtu_rsp_ack = '1')) else '0';
 
 -- transfer_pck FSM indicates that transfer already started or is finished, 
-tp_transfer_valid <= '1' when (s_transfer_pck = S_TRANSFERED or
-                                  s_transfer_pck = S_TRANSFER or
-                                  s_transfer_pck = S_TOO_LONG_TRANSFER) else '0';
-
+tp_transfer_valid <= '1' when (s_transfer_pck            = S_TRANSFERED         or
+                                  s_transfer_pck         = S_TRANSFER           or
+                                  s_transfer_pck         = S_TOO_LONG_TRANSFER  or
+                                  tp_transfer_ready      = '1'                  or
+                                  tp_transfer_rtu_valid  = '1'                  or
+                                  tp_transfer_wait_sof   = '1'                  or
+                                  tp_transfer_set_usecnt = '1') else 
+                     '0';
+
+----------------------------------- this is nasty but should work.... ------------------------
+-- we need to detect cases where the decision about entering transfer state is being made...
+-- so I recreate the "if" statement which can cause the s_transfer_pck FSM to enter
+-- the S_TRANSFER state. THIS IS NASTY but tell me better way....
+tp_transfer_ready     <= '1' when ( s_transfer_pck       = S_READY                   and
+                                   (rtu_rsp_ack          = '0' or  tp_drop    = '0') and
+                                    rtu_rsp_ack          = '1'                       and
+                                    in_pck_sof           = '1'                       and
+                                    current_usecnt       = current_pckstart_usecnt   and 
+                                    c_force_usecnt       = FALSE                     and 
+                                    lw_pckstart_pg_clred = '1') else
+                          '0';      
+
+tp_transfer_rtu_valid <= '1' when ( s_transfer_pck       = S_WAIT_RTU_VALID        and
+                                    rp_in_pck_error      = '0'                     and 
+                                    rtu_rsp_ack          = '1'                     and
+                                    tp_drop              = '0'                     and 
+                                    current_usecnt       = current_pckstart_usecnt and
+                                    c_force_usecnt       = FALSE                   and 
+                                    lw_pckstart_pg_clred = '1') else
+                         '0';
+tp_transfer_wait_sof  <= '1' when ( s_transfer_pck       = S_WAIT_SOF              and
+                                    in_pck_sof           = '1'                     and
+                                    current_usecnt       = current_pckstart_usecnt and 
+                                    c_force_usecnt       = FALSE                   and 
+                                    lw_pckstart_pg_clred = '1') else
+                         '0';
+tp_transfer_set_usecnt<= '1' when ( s_transfer_pck        = S_SET_USECNT           and
+                                    mmu_set_usecnt_done_i = '1'                    and 
+                                    tp_need_pckstart_usecnt_set = '1'              and
+                                    rp_in_pck_error       = '0'                    and
+                                    mmu_set_usecnt_succeeded_i = '1'               and
+                                    lw_pckstart_pg_clred = '1') else
+                          '0';
+                          
 -- rcv_pck FSM indicates that there is or was error on the received pck
 rp_in_pck_error <= '1' when (rp_in_pck_err = '1' or in_pck_err = '1') else '0';
 
@@ -2102,6 +2194,10 @@ rp_in_pck_error <= '1' when (rp_in_pck_err = '1' or in_pck_err = '1') else '0';
 
   res_info_almsot_full <= mmu_res_almost_full_i(to_integer(unsigned(res_info)));
   res_info_full        <= mmu_res_full_i(to_integer(unsigned(res_info)));
+  
+  cur_res_info_almsot_full <= mmu_res_almost_full_i(to_integer(unsigned(current_res_info)));
+  cur_res_info_full        <= mmu_res_full_i(to_integer(unsigned(current_res_info)));
+
   ---------------------------------------------
   
   p_cnt_unused_pages: process(clk_i)