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[/] [udp_ip_stack/] [tags/] [v2.2/] [rtl/] [vhdl/] [IPv4_TX.vhd] - Rev 10
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---------------------------------------------------------------------------------- -- Company: -- Engineer: Peter Fall -- -- Create Date: 16:20:42 06/01/2011 -- Design Name: -- Module Name: IPv4_TX - Behavioral -- Project Name: -- Target Devices: -- Tool versions: -- Description: -- handle simple IP TX -- doesnt handle segmentation -- dest MAC addr resolution through ARP layer -- Handle IPv4 protocol -- Dependencies: -- -- Revision: -- Revision 0.01 - File Created -- Revision 0.02 - fixed up setting of tx_result control defaults -- Revision 0.03 - Added data_out_first -- Revision 0.04 - Added handling of broadcast address -- Additional Comments: -- ---------------------------------------------------------------------------------- library IEEE; use IEEE.STD_LOGIC_1164.ALL; use IEEE.NUMERIC_STD.ALL; use work.axi.all; use work.ipv4_types.all; use work.arp_types.all; entity IPv4_TX is Port ( -- IP Layer signals ip_tx_start : in std_logic; ip_tx : in ipv4_tx_type; -- IP tx cxns ip_tx_result : out std_logic_vector (1 downto 0); -- tx status (changes during transmission) ip_tx_data_out_ready : out std_logic; -- indicates IP TX is ready to take data -- system signals clk : in STD_LOGIC; -- same clock used to clock mac data and ip data reset : in STD_LOGIC; our_ip_address : in STD_LOGIC_VECTOR (31 downto 0); our_mac_address : in std_logic_vector (47 downto 0); -- ARP lookup signals arp_req_req : out arp_req_req_type; arp_req_rslt : in arp_req_rslt_type; -- 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 mac_data_out_ready : in std_logic; -- indicates system ready to consume data mac_data_out_valid : out std_logic; -- indicates data out is valid mac_data_out_first : out std_logic; -- with data out valid indicates the first byte of a frame mac_data_out_last : out std_logic; -- with data out valid indicates the last byte of a frame mac_data_out : out std_logic_vector (7 downto 0) -- ethernet frame (from dst mac addr through to last byte of frame) ); end IPv4_TX; architecture Behavioral of IPv4_TX is type tx_state_type is ( IDLE, WAIT_MAC, -- waiting for response from ARP for mac lookup WAIT_CHN, -- waiting for tx access to MAC channel SEND_ETH_HDR, -- sending the ethernet header SEND_IP_HDR, -- sending the IP header SEND_USER_DATA -- sending the users data ); type crc_state_type is (IDLE,TOT_LEN,ID,FLAGS,TTL,CKS,SAH,SAL,DAH,DAL,FINAL,WAIT_END); type count_mode_type is (RST, INCR, HOLD); type settable_cnt_type is (RST, SET, INCR, HOLD); type set_clr_type is (SET, CLR, HOLD); -- Configuration constant IP_TTL : std_logic_vector (7 downto 0) := x"80"; -- TX state variables signal tx_state : tx_state_type; signal tx_count : unsigned (11 downto 0); signal tx_result_reg : std_logic_vector (1 downto 0); signal tx_mac : std_logic_vector (47 downto 0); signal tx_mac_chn_reqd : std_logic; signal tx_hdr_cks : std_logic_vector (23 downto 0); signal mac_lookup_req : std_logic; signal crc_state : crc_state_type; signal arp_req_ip_reg : std_logic_vector (31 downto 0); signal mac_data_out_ready_reg : std_logic; -- tx control signals signal next_tx_state : tx_state_type; signal set_tx_state : std_logic; signal next_tx_result : std_logic_vector (1 downto 0); signal set_tx_result : std_logic; signal tx_mac_value : std_logic_vector (47 downto 0); signal set_tx_mac : std_logic; signal tx_count_val : unsigned (11 downto 0); signal tx_count_mode : settable_cnt_type; signal tx_data : std_logic_vector (7 downto 0); signal set_last : std_logic; signal set_chn_reqd : set_clr_type; signal set_mac_lku_req : set_clr_type; signal tx_data_valid : std_logic; -- indicates whether data is valid to tx or not -- tx temp signals signal total_length : std_logic_vector (15 downto 0); -- computed combinatorially from header size FUNCTION inv_if_one(s1:std_logic_vector;en:std_logic) return std_logic_vector is --this function inverts all the bits of a vector if --'en' is '1'. VARIABLE Z : std_logic_vector(s1'high downto s1'low); BEGIN FOR i IN (s1'low) to s1'high LOOP Z(i) := en XOR s1(i); END LOOP; RETURN Z; END inv_if_one; -- end function -- IP datagram header format -- -- 0 4 8 16 19 24 31 -- -------------------------------------------------------------------------------------------- -- | Version | *Header | Service Type | Total Length including header | -- | (4) | Length | (ignored) | (in bytes) | -- -------------------------------------------------------------------------------------------- -- | Identification | Flags | Fragment Offset | -- | | | (in 32 bit words) | -- -------------------------------------------------------------------------------------------- -- | Time To Live | Protocol | Header Checksum | -- | (ignored) | | | -- -------------------------------------------------------------------------------------------- -- | Source IP Address | -- | | -- -------------------------------------------------------------------------------------------- -- | Destination IP Address | -- | | -- -------------------------------------------------------------------------------------------- -- | Options (if any - ignored) | Padding | -- | | (if needed) | -- -------------------------------------------------------------------------------------------- -- | Data | -- | | -- -------------------------------------------------------------------------------------------- -- | .... | -- | | -- -------------------------------------------------------------------------------------------- -- -- * - in 32 bit words begin ----------------------------------------------------------------------- -- combinatorial process to implement FSM and determine control signals ----------------------------------------------------------------------- tx_combinatorial : process( -- input signals ip_tx_start, ip_tx, clk, our_ip_address, our_mac_address, arp_req_rslt, mac_tx_granted, mac_data_out_ready, -- state variables tx_state, tx_count, tx_result_reg, tx_mac, tx_mac_chn_reqd, mac_lookup_req, tx_hdr_cks, arp_req_ip_reg, mac_data_out_ready_reg, -- control signals next_tx_state, set_tx_state, next_tx_result, set_tx_result, tx_mac_value, set_tx_mac, tx_count_mode, tx_data, set_last, set_chn_reqd, set_mac_lku_req, total_length, tx_data_valid, tx_count_val ) begin -- set output followers ip_tx_result <= tx_result_reg; mac_tx_req <= tx_mac_chn_reqd; arp_req_req.lookup_req <= mac_lookup_req; arp_req_req.ip <= arp_req_ip_reg; -- set initial values for combinatorial outputs mac_data_out_first <= '0'; case tx_state is when SEND_ETH_HDR | SEND_IP_HDR => mac_data_out <= tx_data; tx_data_valid <= mac_data_out_ready; -- generated internally mac_data_out_last <= set_last; when SEND_USER_DATA => mac_data_out <= ip_tx.data.data_out; tx_data_valid <= ip_tx.data.data_out_valid; mac_data_out_last <= ip_tx.data.data_out_last; when others => mac_data_out <= (others => '0'); tx_data_valid <= '0'; -- not transmitting during this phase mac_data_out_last <= '0'; end case; mac_data_out_valid <= tx_data_valid and mac_data_out_ready; -- set signal defaults next_tx_state <= IDLE; set_tx_state <= '0'; tx_count_mode <= HOLD; tx_data <= x"00"; set_last <= '0'; set_tx_mac <= '0'; set_chn_reqd <= HOLD; set_mac_lku_req <= HOLD; next_tx_result <= IPTX_RESULT_NONE; set_tx_result <= '0'; tx_count_val <= (others => '0'); tx_mac_value <= (others => '0'); -- set temp signals total_length <= std_logic_vector(unsigned(ip_tx.hdr.data_length) + 20); -- total length = user data length + header length (bytes) -- TX FSM case tx_state is when IDLE => ip_tx_data_out_ready <= '0'; -- in this state, we are unable to accept user data for tx tx_count_mode <= RST; set_chn_reqd <= CLR; if ip_tx_start = '1' then -- check header count for error if too high if unsigned(ip_tx.hdr.data_length) > 1480 then next_tx_result <= IPTX_RESULT_ERR; set_tx_result <= '1'; else next_tx_result <= IPTX_RESULT_SENDING; set_tx_result <= '1'; -- TODO - check if we already have the mac addr for this ip, if so, bypass the WAIT_MAC state if ip_tx.hdr.dst_ip_addr = IP_BC_ADDR then -- for IP broadcast, dont need to look up the MAC addr tx_mac_value <= MAC_BC_ADDR; set_tx_mac <= '1'; next_tx_state <= WAIT_CHN; set_tx_state <= '1'; else -- need to req the mac address for this ip set_mac_lku_req <= SET; next_tx_state <= WAIT_MAC; set_tx_state <= '1'; end if; end if; else set_mac_lku_req <= CLR; end if; when WAIT_MAC => ip_tx_data_out_ready <= '0'; -- in this state, we are unable to accept user data for tx set_mac_lku_req <= CLR; -- clear the request - will have been latched in the ARP layer if arp_req_rslt.got_mac = '1' then -- save the MAC we got back from the ARP lookup tx_mac_value <= arp_req_rslt.mac; set_tx_mac <= '1'; set_chn_reqd <= SET; -- check for optimise when already have the channel if mac_tx_granted = '1' then -- ready to send data next_tx_state <= SEND_ETH_HDR; set_tx_state <= '1'; else next_tx_state <= WAIT_CHN; set_tx_state <= '1'; end if; elsif arp_req_rslt.got_err = '1' then set_mac_lku_req <= CLR; next_tx_result <= IPTX_RESULT_ERR; set_tx_result <= '1'; next_tx_state <= IDLE; set_tx_state <= '1'; end if; when WAIT_CHN => ip_tx_data_out_ready <= '0'; -- in this state, we are unable to accept user data for tx if mac_tx_granted = '1' then -- ready to send data next_tx_state <= SEND_ETH_HDR; set_tx_state <= '1'; end if; -- probably should handle a timeout here when SEND_ETH_HDR => ip_tx_data_out_ready <= '0'; -- in this state, we are unable to accept user data for tx if mac_data_out_ready = '1' then if tx_count = x"00d" then tx_count_mode <= RST; next_tx_state <= SEND_IP_HDR; set_tx_state <= '1'; else tx_count_mode <= INCR; end if; case tx_count is when x"000" => mac_data_out_first <= mac_data_out_ready; tx_data <= tx_mac (47 downto 40); -- trg = mac from ARP lookup when x"001" => tx_data <= tx_mac (39 downto 32); when x"002" => tx_data <= tx_mac (31 downto 24); when x"003" => tx_data <= tx_mac (23 downto 16); when x"004" => tx_data <= tx_mac (15 downto 8); when x"005" => tx_data <= tx_mac (7 downto 0); when x"006" => tx_data <= our_mac_address (47 downto 40); -- src = our mac when x"007" => tx_data <= our_mac_address (39 downto 32); when x"008" => tx_data <= our_mac_address (31 downto 24); when x"009" => tx_data <= our_mac_address (23 downto 16); when x"00a" => tx_data <= our_mac_address (15 downto 8); when x"00b" => tx_data <= our_mac_address (7 downto 0); when x"00c" => tx_data <= x"08"; -- pkt type = 0800 : IP when x"00d" => tx_data <= x"00"; when others => -- shouldnt get here - handle as error next_tx_result <= IPTX_RESULT_ERR; set_tx_result <= '1'; next_tx_state <= IDLE; set_tx_state <= '1'; end case; end if; when SEND_IP_HDR => ip_tx_data_out_ready <= '0'; -- in this state, we are unable to accept user data for tx if mac_data_out_ready = '1' then if tx_count = x"013" then tx_count_val <= x"001"; tx_count_mode <= SET; next_tx_state <= SEND_USER_DATA; set_tx_state <= '1'; else tx_count_mode <= INCR; end if; case tx_count is when x"000" => tx_data <= x"45"; -- v4, 5 words in hdr when x"001" => tx_data <= x"00"; -- service type when x"002" => tx_data <= total_length (15 downto 8); -- total length when x"003" => tx_data <= total_length (7 downto 0); when x"004" => tx_data <= x"00"; -- identification when x"005" => tx_data <= x"00"; when x"006" => tx_data <= x"00"; -- flags and fragment offset when x"007" => tx_data <= x"00"; when x"008" => tx_data <= IP_TTL; -- TTL when x"009" => tx_data <= ip_tx.hdr.protocol; -- protocol when x"00a" => tx_data <= tx_hdr_cks (15 downto 8); -- HDR checksum when x"00b" => tx_data <= tx_hdr_cks (7 downto 0); -- HDR checksum when x"00c" => tx_data <= our_ip_address (31 downto 24); -- src ip when x"00d" => tx_data <= our_ip_address (23 downto 16); when x"00e" => tx_data <= our_ip_address (15 downto 8); when x"00f" => tx_data <= our_ip_address (7 downto 0); when x"010" => tx_data <= ip_tx.hdr.dst_ip_addr (31 downto 24); -- dst ip when x"011" => tx_data <= ip_tx.hdr.dst_ip_addr (23 downto 16); when x"012" => tx_data <= ip_tx.hdr.dst_ip_addr (15 downto 8); when x"013" => tx_data <= ip_tx.hdr.dst_ip_addr (7 downto 0); when others => -- shouldnt get here - handle as error next_tx_result <= IPTX_RESULT_ERR; set_tx_result <= '1'; next_tx_state <= IDLE; set_tx_state <= '1'; end case; end if; when SEND_USER_DATA => ip_tx_data_out_ready <= mac_data_out_ready and mac_data_out_ready_reg; -- in this state, we are always ready to accept user data for tx if mac_data_out_ready = '1' then if ip_tx.data.data_out_valid = '1' or tx_count = x"000" then -- only increment if ready and valid has been subsequently established, otherwise data count moves on too fast if unsigned(tx_count) = unsigned(ip_tx.hdr.data_length) then -- TX terminated due to count - end normally set_last <= '1'; set_chn_reqd <= CLR; tx_data <= ip_tx.data.data_out; next_tx_result <= IPTX_RESULT_SENT; set_tx_result <= '1'; next_tx_state <= IDLE; set_tx_state <= '1'; elsif ip_tx.data.data_out_last = '1' then -- TX terminated due to receiving last indication from upstream - end with error set_last <= '1'; set_chn_reqd <= CLR; tx_data <= ip_tx.data.data_out; next_tx_result <= IPTX_RESULT_ERR; set_tx_result <= '1'; next_tx_state <= IDLE; set_tx_state <= '1'; else -- TX continues tx_count_mode <= INCR; tx_data <= ip_tx.data.data_out; end if; end if; end if; end case; end process; ----------------------------------------------------------------------------- -- sequential process to action control signals and change states and outputs ----------------------------------------------------------------------------- tx_sequential : process (clk,reset,mac_data_out_ready_reg) begin if rising_edge(clk) then mac_data_out_ready_reg <= mac_data_out_ready; else mac_data_out_ready_reg <= mac_data_out_ready_reg; end if; if rising_edge(clk) then if reset = '1' then -- reset state variables tx_state <= IDLE; tx_count <= x"000"; tx_result_reg <= IPTX_RESULT_NONE; tx_mac <= (others => '0'); tx_mac_chn_reqd <= '0'; mac_lookup_req <= '0'; else -- Next tx_state processing if set_tx_state = '1' then tx_state <= next_tx_state; else tx_state <= tx_state; end if; -- tx result processing if set_tx_result = '1' then tx_result_reg <= next_tx_result; else tx_result_reg <= tx_result_reg; end if; -- control arp lookup request case set_mac_lku_req is when SET => arp_req_ip_reg <= ip_tx.hdr.dst_ip_addr; mac_lookup_req <= '1'; when CLR => mac_lookup_req <= '0'; arp_req_ip_reg <= arp_req_ip_reg; when HOLD => mac_lookup_req <= mac_lookup_req; arp_req_ip_reg <= arp_req_ip_reg; end case; -- save MAC if set_tx_mac = '1' then tx_mac <= tx_mac_value; else tx_mac <= tx_mac; end if; -- 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; -- tx_count processing case tx_count_mode is when RST => tx_count <= x"000"; when SET => tx_count <= tx_count_val; when INCR => tx_count <= tx_count + 1; when HOLD => tx_count <= tx_count; end case; end if; end if; end process; ----------------------------------------------------------------------------- -- Process to calculate CRC in parallel with pkt out processing -- this process must yield a valid CRC before it is required to be used in the hdr ----------------------------------------------------------------------------- crc : process (clk,reset) begin if rising_edge(clk) then case crc_state is when IDLE => if ip_tx_start = '1' then tx_hdr_cks <= x"004500"; -- vers & hdr len & service crc_state <= TOT_LEN; end if; when TOT_LEN => tx_hdr_cks <= std_logic_vector (unsigned(tx_hdr_cks) + unsigned(total_length)); crc_state <= ID; when ID => tx_hdr_cks <= tx_hdr_cks; crc_state <= FLAGS; when FLAGS => tx_hdr_cks <= tx_hdr_cks; crc_state <= TTL; when TTL => tx_hdr_cks <= std_logic_vector (unsigned(tx_hdr_cks) + unsigned(IP_TTL & ip_tx.hdr.protocol)); crc_state <= CKS; when CKS => tx_hdr_cks <= tx_hdr_cks; crc_state <= SAH; when SAH => tx_hdr_cks <= std_logic_vector (unsigned(tx_hdr_cks) + unsigned(our_ip_address(31 downto 16))); crc_state <= SAL; when SAL => tx_hdr_cks <= std_logic_vector (unsigned(tx_hdr_cks) + unsigned(our_ip_address(15 downto 0))); crc_state <= DAH; when DAH => tx_hdr_cks <= std_logic_vector (unsigned(tx_hdr_cks) + unsigned(ip_tx.hdr.dst_ip_addr(31 downto 16))); crc_state <= DAL; when DAL => tx_hdr_cks <= std_logic_vector (unsigned(tx_hdr_cks) + unsigned(ip_tx.hdr.dst_ip_addr(15 downto 0))); crc_state <= FINAL; when FINAL => tx_hdr_cks <= inv_if_one(std_logic_vector (unsigned(tx_hdr_cks) + unsigned(tx_hdr_cks(23 downto 16))),'1'); crc_state <= WAIT_END; when WAIT_END => tx_hdr_cks <= tx_hdr_cks; if ip_tx_start = '0' then crc_state <= IDLE; else crc_state <= WAIT_END; end if; end case; end if; end process; end Behavioral;
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