- added transfer dropstate in case of RAM full

- registered ctrl_out.pkt_lost. Cleared on pkt_free
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git-svn-id: http://moon:8086/svn/vhdl/trunk@832 cc03376c-175c-47c8-b038-4cd826a8556b

lib/emac/src/emac_rx.vhd

@@ -54,27 +54,19 @@ ARCHITECTURE behavior OF emac_rx IS
 	signal flush_en			: std_logic;
 	
 	signal fill_ptr			: word_ptr_t;
-	signal fill_ptr_set		: std_logic;
-	signal fill_ptr_adv		: std_logic;
 
 	signal commit_en		: std_logic;
-	signal uncommit_en		: std_logic;
 
 	signal xfer_ram_limit	: word_ptr_t;
 	signal xfer_ram_full	: std_logic;
 	signal xfer_base		: word_ptr_t;
 	signal xfer_size		: word_ptr_t;
 	signal xfer_ptr			: word_ptr_t;
-	signal xfer_cnt			: word_ptr_t;
 	signal xfer_ptr_set		: std_logic;
 	signal xfer_ptr_adv		: std_logic;
 	signal xfer_cnt_set		: std_logic;
 	signal xfer_cnt_adv		: std_logic;
 	signal xfer_rdy			: std_logic;
-	signal xfer_tag			: unsigned(3 downto 0);
-	signal xfer_remain		: unsigned(1 downto 0);
-	signal xfer_odd			: std_logic;
-	signal xfer_remain_en	: std_logic;
 
 	signal ram_en_a			: std_logic;
 	signal ram_we_a			: std_logic;
@@ -111,10 +103,10 @@ ARCHITECTURE behavior OF emac_rx IS
 	signal word_count_ack	: std_logic;
 	signal word_count_vld	: std_logic;
 
-	type host_state_t is (host_init, host_flush, host_idle, host_setup, host_arm, host_fill, host_uncommit);
+	type host_state_t is (host_init, host_flush, host_idle);
 	signal host_s, host_sn : host_state_t;
 
-	type xfer_state_t is (xfer_init, xfer_idle, xfer_setup, xfer_wait, xfer_active, xfer_free);
+	type xfer_state_t is (xfer_init, xfer_idle, xfer_setup, xfer_active, xfer_drop, xfer_free);
 	signal xfer_s, xfer_sn : xfer_state_t;
 
 begin
@@ -122,7 +114,6 @@ begin
 	ctrl_out.rx_size	<= cmd_fifo_dout(31 downto 16);
 	ctrl_out.pkt_avail	<= not cmd_fifo_empty;
 	ctrl_out.rx_er		<= mii_rx_er;
-	ctrl_out.pkt_lost	<= xfer_ram_full;
 
 	dout				<= ram_dout_a;
 
@@ -137,7 +128,7 @@ begin
 	ram_en_b			<= '1';
 	ram_din_b			<= mii_fifo_dout(31 downto 0);
 	ram_addr_b			<= xfer_ptr;
-	ram_we_b			<= xfer_cnt_adv;
+	ram_we_b			<= xfer_ptr_adv;
 	
 	cmd_fifo_we			<= commit_en;
 	cmd_fifo_re			<= ctrl_in.pkt_free_en;
@@ -157,12 +148,10 @@ host_state_next:
 	end process;	
 
 host_state:
-	process(host_s, cmd_fifo_empty, ctrl_in.pkt_read_en, ctrl_in.pkt_req_en)
+	process(host_s)
 	begin
 	
 		flush_en			<= '0';
-		fill_ptr_set		<= '0';
-		fill_ptr_adv		<= '0';
 		
 		host_sn				<= host_s;
 		
@@ -177,25 +166,6 @@ host_state:
 			host_sn 	<= host_idle;
 			
 		when host_idle =>
-			if cmd_fifo_empty = '0' then
-				host_sn		<= host_setup;
-			end if;
-
-		when host_setup =>
-			fill_ptr_set	<= '1';
-			host_sn			<= host_arm;
-
-		when host_arm =>
-			host_sn			<= host_fill;
-
-		when host_fill =>
-			fill_ptr_adv	<= ctrl_in.pkt_read_en;
-			if ctrl_in.pkt_req_en = '1' then
-				host_sn		<= host_uncommit;
-			end if;
-		
-		when host_uncommit =>
-			host_sn			<= host_idle;
 
 		when others => 
 			host_sn			<= host_idle;
@@ -261,23 +231,29 @@ xfer_state:
 		when xfer_setup =>
 			xfer_cnt_set	<= '1';
 			xfer_ptr_set	<= '1';
-			xfer_sn			<= xfer_wait;
-		
-		when xfer_wait =>
 			xfer_sn			<= xfer_active;
-
+		
 		when xfer_active =>
 			mii_fifo_re		<= '1';
 			xfer_cnt_adv	<= not mii_fifo_empty;
 			xfer_ptr_adv	<= not mii_fifo_empty;
 			if xfer_ram_full = '1' then
-				xfer_sn		<= xfer_free;
+				xfer_sn		<= xfer_drop;
 			elsif xfer_rdy = '1' then
 				if mii_fifo_empty = '1' then
 					xfer_sn		<= xfer_free;
 				end if;
 			end if;	
 
+		when xfer_drop =>
+			mii_fifo_re		<= '1';
+			xfer_cnt_adv	<= not mii_fifo_empty;
+			if xfer_rdy = '1' then
+				if mii_fifo_empty = '1' then
+					xfer_sn		<= xfer_free;
+				end if;
+			end if;			
+
 		when xfer_free =>
 			word_count_ack	<= '1';
 			commit_en		<= not xfer_ram_full;
@@ -290,6 +266,21 @@ xfer_state:
 	end process;
 
 ------------------------------------------------------------------
+pkt_lost_register:
+	process(clk)
+	begin
+		if rising_edge(clk) then
+			if flush_en = '1' then
+				ctrl_out.pkt_lost	<= '0';
+			elsif word_count_ack = '1' and xfer_ram_full = '1' then
+				ctrl_out.pkt_lost	<= '1';
+			elsif ctrl_in.pkt_free_en = '1' then
+				ctrl_out.pkt_lost	<= '0';
+			end if;
+		end if;	
+			
+	end process;	
+
 xfer_limit_register:
 	process(clk)
 	begin