[NIC] bugfix: zero ack_cnt when src_o.cyc is LOW

when src_i.ack stayed HIGH after src_o.cyc when LOW (which is clearly a bug), the ack_cnt was still counting acks (which should confirm all STABed data words). Thus, when new frame came (src_o.cyc HIGH again), the ack_cnt was completly lost and weired things happened. So, now the src_i.ack is ignored when src_o.cyc is LOW.

[NIC] bugfix: zero ack_cnt when src_o.cyc is LOW
when src_i.ack stayed HIGH after src_o.cyc when LOW (which is clearly a bug), the ack_cnt was still counting acks (which should confirm all STABed data words). Thus, when new frame came (src_o.cyc HIGH again), the ack_cnt was completly lost and weired things happened. So, now the src_i.ack is ignored when src_o.cyc is LOW.
8145f266 · Maciej Lipinski · 6da3c2e9 · 8145f266
Commit 8145f266 authored Mar 25, 2015 by Maciej Lipinski
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Showing with 6 additions and 4 deletions

nic_tx_fsm.vhd modules/wrsw_nic/nic_tx_fsm.vhd +6 -4

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--- a/modules/wrsw_nic/nic_tx_fsm.vhd
+++ b/modules/wrsw_nic/nic_tx_fsm.vhd
@@ -161,6 +161,7 @@ architecture behavioral of nic_tx_fsm is

  signal ack_count : unsigned(3 downto 0);
 	signal src_stb_int	:	std_logic;
+  signal src_cyc_int          :  std_logic;

 begin  -- behavioral

@@ -180,6 +181,7 @@ begin  -- behavioral

  txdesc_new_o <= cur_tx_desc;
  src_o.stb 	 <= src_stb_int;
+  src_o.cyc     <= src_cyc_int;
 	--because it's validated with rtu_rsp_valid_o and sw_core stores it to internal register on rtu_rsp_valid strobe
  rtu_dst_port_mask_o <= cur_tx_desc.dpm(g_port_mask_bits-1 downto 0);
  rtu_prio_o          <= (others => '0');
@@ -188,7 +190,7 @@ begin  -- behavioral
  count_acks: process(clk_sys_i)
  begin
    if rising_edge(clk_sys_i) then
-      if(rst_n_i='0') then
+      if(rst_n_i='0' or src_cyc_int = '0') then
        ack_count <= (others=>'0');
      elsif(src_stb_int = '1' and src_i.stall = '0' and src_i.ack = '0') then
        ack_count <= ack_count + 1;
@@ -242,7 +244,7 @@ begin  -- behavioral
        txdesc_write_o          <= '0';
        txdesc_reload_current_o <= '0';

-        src_o.cyc   <= '0';
+        src_cyc_int   <= '0';
        src_stb_int <= '0';
        src_o.we  	<= '1';
        src_o.adr 	<= (others => '0');
@@ -302,7 +304,7 @@ begin  -- behavioral
            if( ( (src_i.stall = '0' and g_cyc_on_stall = false) or g_cyc_on_stall = true)
                and buf_grant_i = '0') then

-              src_o.cyc <= '1';
+              src_cyc_int <= '1';
              tx_buf_addr        <= tx_buf_addr + 1;
              state              <= TX_STATUS;
              tx_data_reg <= f_buf_swap_endian_32(buf_data_i);
@@ -451,7 +453,7 @@ begin  -- behavioral
            end if;

          when TX_UPDATE_DESCRIPTOR =>
-            src_o.cyc 							<= '0';
+            src_cyc_int 							<= '0';
            txdesc_write_o          <= '1';
            txdesc_reload_current_o <= cur_tx_desc.error;
            cur_tx_desc.ready       <= '0';