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[/] [udp_ip_stack/] [tags/] [v2.0/] [rtl/] [vhdl/] [arp_TX.vhd] - Rev 27
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---------------------------------------------------------------------------------- -- Company: -- Engineer: Peter Fall -- -- Create Date: 12:00:04 05/31/2011 -- Design Name: -- Module Name: arp_tx - Behavioral -- Project Name: -- Target Devices: -- Tool versions: -- Description: -- handle transmission of an ARP packet. -- -- Dependencies: -- -- Revision: -- Revision 0.01 - File Created - refactored this arp_tx module from the complete arp v0.02 module -- Additional Comments: -- ---------------------------------------------------------------------------------- library IEEE; use IEEE.STD_LOGIC_1164.ALL; use IEEE.NUMERIC_STD.ALL; use work.arp_types.all; entity arp_tx is Port ( -- control signals send_I_have : in std_logic; -- pulse will be latched arp_entry : in arp_entry_t; -- arp target for I_have req (will be latched) send_who_has : in std_logic; -- pulse will be latched ip_entry : in STD_LOGIC_VECTOR (31 downto 0); -- IP target for who_has req (will be latched) -- MAC layer TX signals mac_tx_req : out std_logic; -- indicates that ip wants access to channel (stays up for as long as tx) mac_tx_granted : in std_logic; -- indicates that access to channel has been granted data_out_ready : in std_logic; -- indicates system ready to consume data data_out_valid : out std_logic; -- indicates data out is valid data_out_first : out std_logic; -- with data out valid indicates the first byte of a frame data_out_last : out std_logic; -- with data out valid indicates the last byte of a frame data_out : out std_logic_vector (7 downto 0); -- ethernet frame (from dst mac addr through to last byte of frame) -- system signals our_mac_address : in STD_LOGIC_VECTOR (47 downto 0); our_ip_address : in STD_LOGIC_VECTOR (31 downto 0); tx_clk : in std_logic; reset : in std_logic ); end arp_tx; architecture Behavioral of arp_tx is type count_mode_t is (RST,INCR,HOLD); type set_clr_t is (SET, CLR, HOLD); type tx_state_t is (IDLE,WAIT_MAC,SEND); type tx_mode_t is (REPLY,REQUEST); -- state variables signal tx_mac_chn_reqd : std_logic; signal tx_state : tx_state_t; signal tx_count : unsigned (7 downto 0); signal send_I_have_reg : std_logic; signal send_who_has_reg : std_logic; signal I_have_target : arp_entry_t; -- latched target for "I have" request signal who_has_target : std_logic_vector (31 downto 0); -- latched IP for "who has" request signal tx_mode : tx_mode_t; -- what sort of tx to make signal target : arp_entry_t; -- target to send to -- busses signal next_tx_state : tx_state_t; signal tx_mode_val : tx_mode_t; signal target_val : arp_entry_t; -- tx control signals signal set_tx_state : std_logic; signal tx_count_mode : count_mode_t; signal set_chn_reqd : set_clr_t; signal kill_data_out_valid : std_logic; signal set_send_I_have : set_clr_t; signal set_send_who_has : set_clr_t; signal set_tx_mode : std_logic; signal set_target : std_logic; begin tx_combinatorial : process ( -- input signals send_I_have, send_who_has, arp_entry, ip_entry, data_out_ready, mac_tx_granted, our_mac_address, our_ip_address, reset, -- state variables tx_state, tx_count, tx_mac_chn_reqd, I_have_target, who_has_target, send_I_have_reg, send_who_has_reg, tx_mode, target, -- busses next_tx_state, tx_mode_val, target_val, -- control signals tx_count_mode, kill_data_out_valid, set_send_I_have, set_send_who_has, set_chn_reqd, set_tx_mode, set_target ) begin -- set output followers mac_tx_req <= tx_mac_chn_reqd; -- set combinatorial output defaults data_out_first <= '0'; case tx_state is when SEND => if data_out_ready = '1' and kill_data_out_valid = '0' then data_out_valid <= '1'; else data_out_valid <= '0'; end if; when OTHERS => data_out_valid <= '0'; end case; -- set bus defaults next_tx_state <= IDLE; tx_mode_val <= REPLY; target_val.ip <= (others => '0'); target_val.mac <= (others => '0'); -- set signal defaults set_tx_state <= '0'; tx_count_mode <= HOLD; data_out <= x"00"; data_out_last <= '0'; set_chn_reqd <= HOLD; kill_data_out_valid <= '0'; set_send_I_have <= HOLD; set_send_who_has <= HOLD; set_tx_mode <= '0'; set_target <= '0'; -- process requests in regardless of FSM state if send_I_have = '1' then set_send_I_have <= SET; end if; if send_who_has = '1' then set_send_who_has <= SET; end if; -- TX FSM case tx_state is when IDLE => tx_count_mode <= RST; if send_I_have_reg = '1' then set_chn_reqd <= SET; tx_mode_val <= REPLY; set_tx_mode <= '1'; target_val <= I_have_target; set_target <= '1'; set_send_I_have <= CLR; next_tx_state <= WAIT_MAC; set_tx_state <= '1'; elsif send_who_has_reg = '1' then set_chn_reqd <= SET; tx_mode_val <= REQUEST; set_tx_mode <= '1'; target_val.ip <= who_has_target; target_val.mac <= (others => '0'); set_target <= '1'; set_send_who_has <= CLR; next_tx_state <= WAIT_MAC; set_tx_state <= '1'; else set_chn_reqd <= CLR; end if; when WAIT_MAC => tx_count_mode <= RST; if mac_tx_granted = '1' then next_tx_state <= SEND; set_tx_state <= '1'; end if; -- TODO - should handle timeout here when SEND => if data_out_ready = '1' then tx_count_mode <= INCR; end if; case tx_count is when x"00" => data_out_first <= data_out_ready; data_out <= x"ff"; -- dst = broadcast when x"01" => data_out <= x"ff"; when x"02" => data_out <= x"ff"; when x"03" => data_out <= x"ff"; when x"04" => data_out <= x"ff"; when x"05" => data_out <= x"ff"; when x"06" => data_out <= our_mac_address (47 downto 40); -- src = our mac when x"07" => data_out <= our_mac_address (39 downto 32); when x"08" => data_out <= our_mac_address (31 downto 24); when x"09" => data_out <= our_mac_address (23 downto 16); when x"0a" => data_out <= our_mac_address (15 downto 8); when x"0b" => data_out <= our_mac_address (7 downto 0); when x"0c" => data_out <= x"08"; -- pkt type = 0806 : ARP when x"0d" => data_out <= x"06"; when x"0e" => data_out <= x"00"; -- HW type = 0001 : eth when x"0f" => data_out <= x"01"; when x"10" => data_out <= x"08"; -- protocol = 0800 : ip when x"11" => data_out <= x"00"; when x"12" => data_out <= x"06"; -- HW size = 06 when x"13" => data_out <= x"04"; -- prot size = 04 when x"14" => data_out <= x"00"; -- opcode = when x"15" => if tx_mode = REPLY then data_out <= x"02"; -- 02 : REPLY else data_out <= x"01"; -- 01 : REQ end if; when x"16" => data_out <= our_mac_address (47 downto 40); -- sender mac when x"17" => data_out <= our_mac_address (39 downto 32); when x"18" => data_out <= our_mac_address (31 downto 24); when x"19" => data_out <= our_mac_address (23 downto 16); when x"1a" => data_out <= our_mac_address (15 downto 8); when x"1b" => data_out <= our_mac_address (7 downto 0); when x"1c" => data_out <= our_ip_address (31 downto 24); -- sender ip when x"1d" => data_out <= our_ip_address (23 downto 16); when x"1e" => data_out <= our_ip_address (15 downto 8); when x"1f" => data_out <= our_ip_address (7 downto 0); when x"20" => data_out <= target.mac (47 downto 40); -- target mac when x"21" => data_out <= target.mac (39 downto 32); when x"22" => data_out <= target.mac (31 downto 24); when x"23" => data_out <= target.mac (23 downto 16); when x"24" => data_out <= target.mac (15 downto 8); when x"25" => data_out <= target.mac (7 downto 0); when x"26" => data_out <= target.ip (31 downto 24); -- target ip when x"27" => data_out <= target.ip (23 downto 16); when x"28" => data_out <= target.ip (15 downto 8); when x"29" => data_out <= target.ip(7 downto 0); data_out_last <= '1'; when x"2a" => kill_data_out_valid <= '1'; -- data is no longer valid next_tx_state <= IDLE; set_tx_state <= '1'; when others => next_tx_state <= IDLE; set_tx_state <= '1'; end case; end case; end process; tx_sequential : process (tx_clk) begin if rising_edge(tx_clk) then if reset = '1' then -- reset state variables tx_state <= IDLE; tx_count <= (others => '0'); tx_mac_chn_reqd <= '0'; send_I_have_reg <= '0'; send_who_has_reg <= '0'; who_has_target <= (others => '0'); I_have_target.ip <= (others => '0'); I_have_target.mac <= (others => '0'); target.ip <= (others => '0'); target.mac <= (others => '0'); else -- normal (non reset) processing -- Next tx_state processing if set_tx_state = '1' then tx_state <= next_tx_state; else tx_state <= tx_state; end if; -- input request latching case set_send_I_have is when SET => send_I_have_reg <= '1'; I_have_target <= arp_entry; when CLR => send_I_have_reg <= '0'; I_have_target <= I_have_target; when HOLD => send_I_have_reg <= send_I_have_reg; I_have_target <= I_have_target; end case; case set_send_who_has is when SET => send_who_has_reg <= '1'; who_has_target <= ip_entry; when CLR => send_who_has_reg <= '0'; who_has_target <= who_has_target; when HOLD => send_who_has_reg <= send_who_has_reg; who_has_target <= who_has_target; end case; -- tx mode if set_tx_mode = '1' then tx_mode <= tx_mode_val; else tx_mode <= tx_mode; end if; -- target latching if set_target = '1' then target <= target_val; else target <= target; end if; -- tx_count processing case tx_count_mode is when RST => tx_count <= x"00"; when INCR => tx_count <= tx_count + 1; when HOLD => tx_count <= tx_count; end case; -- control access request to mac tx chn case set_chn_reqd is when SET => tx_mac_chn_reqd <= '1'; when CLR => tx_mac_chn_reqd <= '0'; when HOLD => tx_mac_chn_reqd <= tx_mac_chn_reqd; end case; end if; end if; end process; end Behavioral;
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