arp: Add timeout

design/top_hwitl.vhd

@@ -215,9 +215,13 @@ architecture eth of top_hwitl is
 	signal arp_in  : arp_in_t;
 begin
 	trashernet_arp_inst : entity trashernet.trashernet_arp
+		generic map(
+			TIMEOUT_TICK_FREQ => F_CLK
+		)
 		port map(
 			clk             => clk,
 			rst             => rst,
+			timeout_tick    => '1',
 			mac_config      => ETH_CONFIG,
 			ip_config       => IP_CONFIG,
 			arp_out         => arp_out,

trashernet/trashernet_arp.vhd

@@ -16,10 +16,14 @@ use ieee.numeric_std.all;
 use work.trashernet_pkg.all;
 
 entity trashernet_arp is
+	generic(
+		TIMEOUT_TICK_FREQ : integer
+	);
 	port(
 		-- Global
 		clk             : in  std_logic; -- Global clock
 		rst             : in  std_logic; -- Asynchronous reset
+		timeout_tick    : in  std_logic; -- Global timeout tick strobe
 
 		-- Configuration
 		mac_config      : in  configuration_t; -- Trashernet MAC configuration
@@ -43,6 +47,8 @@ architecture rtl of trashernet_arp is
 	constant OPER_REQUEST : byte_vector := (x"00", x"01");
 	constant OPER_REPLY   : byte_vector := (x"00", x"02");
 
+	constant ARP_TIMEOUT : time := 1 sec;
+
 	signal arp_tx_reply_rq  : std_logic; -- Request to transmit an ARP reply
 	signal arp_tx_reply_tha : mac_addr_t; -- Target MAC to use in reply (SHA in received packet)
 	signal arp_tx_reply_tpa : ip_addr_t; -- Target IP to use in reply (SPA in received packet)
@@ -113,6 +119,22 @@ begin
 		query_mac_found    <= '1' when (arp_tx_request_tpa = replied_ip) else '0';
 		arp_out.arp_mac    <= replied_mac;
 		arp_tx_request_tpa <= arp_in.arp_ip;
+
+		timeout_timer_inst : entity work.timer
+			generic map(
+				F_TICK    => TIMEOUT_TICK_FREQ,
+				DURATION  => ARP_TIMEOUT,
+				AUTOSTART => false
+			)
+			port map(
+				clk         => clk,
+				rst         => rst,
+				tick        => timeout_tick,
+				start       => arp_tx_request_rq,
+				expired     => query_timeout,
+				expired_stb => open
+			);
+
 	end block resolver;
 
 	rx : block