modules/swcore: assure proper pages storage to linked list when LL goes through S_SOF_ON_WR

If LL FSM goes through S_SOF_ON_WR state we have to ensure that the state of mpm_dlast and new_pck_first_page is properly stored for S_IDLE state. Otherwise, if RCV FSM is in S_RCV_DATA only for one cycle (and then goes to DROP) we were not storing the start page with _valid_ and _eof_ high.

modules/swcore: assure proper pages storage to linked list when LL goes through S_SOF_ON_WR
If LL FSM goes through S_SOF_ON_WR state we have to ensure that the state of mpm_dlast and new_pck_first_page is properly stored for S_IDLE state. Otherwise, if RCV FSM is in S_RCV_DATA only for one cycle (and then goes to DROP) we were not storing the start page with _valid_ and _eof_ high.
c0bfa27a · Grzegorz Daniluk · 80ecfc2f · c0bfa27a
Commit c0bfa27a authored May 08, 2015 by Grzegorz Daniluk
Hide whitespace changes
Inline Side-by-side

Showing with 38 additions and 23 deletions

xswc_input_block.vhd modules/wrsw_swcore/xswc_input_block.vhd +38 -23

No files found.
--- a/modules/wrsw_swcore/xswc_input_block.vhd
+++ b/modules/wrsw_swcore/xswc_input_block.vhd
@@ -817,12 +817,20 @@ begin  --archS_PCKSTART_SET_AND_REQ
      else

        -- default values:
-        mpm_dlast           <= '0';
+        if(mpm_dlast = '1' and s_ll_write = S_SOF_ON_WR) then
+          mpm_dlast           <= '1';
+        else
+          mpm_dlast           <= '0';
+        end if;
        mpm_dvalid          <= '0';
        in_pck_eof_on_pause <= '0';
-        --if(s_ll_write = S_WRITE) then
-          new_pck_first_page  <= '0';
-        --end if;
+        if(new_pck_first_page = '1' and s_ll_write = S_SOF_ON_WR) then
+          -- in case LL FSM is in S_SOF_ON_WR, we need to keep
+          -- new_pck_first_page signal longer, otherwise we lose it..
+          new_pck_first_page <= '1';
+        else
+          new_pck_first_page <= '0';
+        end if;

        case s_rcv_pck is
          --===========================================================================================
@@ -906,9 +914,6 @@ begin  --archS_PCKSTART_SET_AND_REQ
            --===========================================================================================
            rcv_pckstart_new <= '0';
            -- to extend the span of new_pck_first_page into s_ll_write = S_IDLE, when there is S_SOF
-            if(s_ll_write = S_SOF_ON_WR and new_pck_first_page = '1') then
-              new_pck_first_page <='1';
-            end if;
            if(in_pck_dvalid = '1') then
              in_pck_dvalid_d0 <= in_pck_dvalid;
              in_pck_dat_d0    <= in_pck_dat;
@@ -1151,7 +1156,7 @@ begin  --archS_PCKSTART_SET_AND_REQ
  -- requestd, but the request takes time (more then 1 cycle). so we delay setting of 
  -- *rp_rcv_first_page* to be able to copie the addr to be clearted (in ll_write FSM) from 
  -- current_pckstart_pageaddr in case *rp_rcv_first_page* is asserted
-  if(new_pck_first_page = '1' and rp_rcv_first_page = '0') then
+  if(new_pck_first_page = '1' and rp_rcv_first_page = '0' and mpm_dlast = '0') then
    rp_rcv_first_page <= '1';
  elsif((mpm_pg_req_i = '1' or mpm_dlast = '1') and rp_rcv_first_page = '1') then
    rp_rcv_first_page <= '0';
@@ -1951,25 +1956,35 @@ begin
          --     indication
          if(pckstart_page_in_advance = '1' or new_pck_first_page = '1') then
            ll_wr_req      <= '1';
-            ll_entry.valid <= '0';
-            ll_entry.eof   <= '0';
-
-            -- if we've already started sending new pck, then new page already can be allocated
-            -- (this is because we trigger allocation of new pckstart_pageaddr as soon as
-            -- we use it at the beginning of RCV_DATA)
-            -- but we need to clear previously allocated pckstart_pageaddr (this was stored
-            -- in current_pckstart_pageaddr).
-            -- such situation can happen only within the first page, if pckstart_pageaddr
-            -- is not allocated by the end of first page,  we PAUSE..
-            if(rp_rcv_first_page = '1') then
-              ll_entry.addr <= current_pckstart_pageaddr;
+            -- it may happen that LL FSM goes from SOF_ON_WR to IDLE and we
+            -- managed to write only one word to the start page before deciding
+            -- we drop the rest of the frame. Hence the conditional below:
+            if(mpm_dlast_d0 = '1') then
+              ll_entry.valid <= '1';
+              ll_entry.eof   <= '1';
+              ll_entry.size  <= rp_ll_entry_size;
+              ll_entry.addr  <= rp_ll_entry_addr;
+              ll_entry.first_page_clr  <= '0';
            else
-              ll_entry.addr <= pckstart_pageaddr;
+              ll_entry.valid <= '0';
+              ll_entry.eof   <= '0';
+              ll_entry.size  <= (others => '0');
+              ll_entry.first_page_clr  <= '1';
+              -- if we've already started sending new pck, then new page already can be allocated
+              -- (this is because we trigger allocation of new pckstart_pageaddr as soon as
+              -- we use it at the beginning of RCV_DATA)
+              -- but we need to clear previously allocated pckstart_pageaddr (this was stored
+              -- in current_pckstart_pageaddr).
+              -- such situation can happen only within the first page, if pckstart_pageaddr
+              -- is not allocated by the end of first page,  we PAUSE..
+              if(rp_rcv_first_page = '1') then
+                ll_entry.addr <= current_pckstart_pageaddr;
+              else
+                ll_entry.addr <= pckstart_pageaddr;
+              end if;
            end if;
-            ll_entry.size            <= (others => '0');
            ll_entry.next_page       <= (others => '0');
            ll_entry.next_page_valid <= '0';
-            ll_entry.first_page_clr  <= '1';
            s_ll_write               <= S_WRITE;
          end if;