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pjf |
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-- Company:
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-- Engineer: Peter Fall
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--
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-- Create Date: 12:00:04 05/31/2011
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-- Design Name:
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-- Module Name: arp - Behavioral
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-- Project Name:
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-- Target Devices:
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-- Tool versions:
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-- Description:
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-- handle simple IP lookup in cache
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-- request cache fill through ARP protocol if required
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-- cache is simple 1 deep
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-- Handle ARP protocol
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-- Respond to ARP requests and replies
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-- Ignore pkts that are not ARP
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-- Ignore pkts that are not addressed to us
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--
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-- Dependencies:
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--
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-- Revision:
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-- Revision 0.01 - File Created
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4 |
pjf |
-- Revision 0.02 - Added req for mac tx and wait for grant
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-- Revision 0.03 - Added data_out_first
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-- Additional Comments:
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--
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----------------------------------------------------------------------------------
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library IEEE;
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use IEEE.STD_LOGIC_1164.ALL;
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use IEEE.NUMERIC_STD.ALL;
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use work.arp_types.all;
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entity arp is
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Port (
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-- lookup request signals
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arp_req_req : in arp_req_req_type;
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arp_req_rslt : out arp_req_rslt_type;
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-- MAC layer RX signals
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data_in_clk : in STD_LOGIC;
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reset : in STD_LOGIC;
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data_in : in STD_LOGIC_VECTOR (7 downto 0); -- ethernet frame (from dst mac addr through to last byte of frame)
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data_in_valid : in STD_LOGIC; -- indicates data_in valid on clock
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data_in_last : in STD_LOGIC; -- indicates last data in frame
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-- MAC layer TX signals
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mac_tx_req : out std_logic; -- indicates that ip wants access to channel (stays up for as long as tx)
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mac_tx_granted : in std_logic; -- indicates that access to channel has been granted
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data_out_clk : in std_logic;
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data_out_ready : in std_logic; -- indicates system ready to consume data
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data_out_valid : out std_logic; -- indicates data out is valid
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data_out_first : out std_logic; -- with data out valid indicates the first byte of a frame
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data_out_last : out std_logic; -- with data out valid indicates the last byte of a frame
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data_out : out std_logic_vector (7 downto 0); -- ethernet frame (from dst mac addr through to last byte of frame)
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-- system signals
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our_mac_address : in STD_LOGIC_VECTOR (47 downto 0);
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our_ip_address : in STD_LOGIC_VECTOR (31 downto 0);
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req_count : out STD_LOGIC_VECTOR(7 downto 0) -- count of arp pkts received
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);
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end arp;
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architecture Behavioral of arp is
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type req_state_type is (IDLE,LOOKUP,REQUEST,WAIT_REPLY);
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type rx_state_type is (IDLE,PARSE,PROCESS_ARP,WAIT_END);
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type rx_event_type is (NO_EVENT,DATA);
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type count_mode_type is (RST,INCR,HOLD);
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type arp_oper_type is (NOP,REQUEST,REPLY);
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type set_clr_type is (SET, CLR, HOLD);
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type tx_state_type is (IDLE,WAIT_MAC,SEND);
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type arp_entry_type is record
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ip : std_logic_vector (31 downto 0);
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mac : std_logic_vector (47 downto 0);
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is_valid : std_logic;
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reply_required : std_logic;
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end record;
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-- state variables
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signal req_state : req_state_type;
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signal req_ip_addr : std_logic_vector (31 downto 0); -- IP address to lookup
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signal mac_addr_found : STD_LOGIC_VECTOR (47 downto 0); -- mac address found
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signal mac_addr_valid_reg: std_logic;
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signal send_request_needed : std_logic;
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signal tx_mac_chn_reqd : std_logic;
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signal rx_state : rx_state_type;
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signal rx_count : unsigned (7 downto 0);
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signal arp_operation : arp_oper_type;
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signal arp_req_count : unsigned (7 downto 0);
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signal arp_entry : arp_entry_type; -- arp entry store
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signal new_arp_entry : arp_entry_type;
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signal tx_state : tx_state_type;
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signal tx_count : unsigned (7 downto 0);
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-- FIXME - remove these debug state signals
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signal arp_err_data : std_logic_vector (7 downto 0);
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signal set_err_data : std_logic;
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attribute keep : string;
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attribute keep of arp_err_data : signal is "true";
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-- requester control signals
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signal next_req_state : req_state_type;
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signal set_req_state : std_logic;
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signal set_req_ip : std_logic;
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signal set_mac_addr : std_logic;
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signal set_mac_addr_invalid : std_logic;
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signal set_send_req : std_logic;
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signal clear_send_req : std_logic;
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-- rx control signals
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signal next_rx_state : rx_state_type;
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signal set_rx_state : std_logic;
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signal rx_event : rx_event_type;
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signal rx_count_mode : count_mode_type;
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signal set_arp_oper : std_logic;
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signal arp_oper_set_val : arp_oper_type;
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signal dataval : std_logic_vector (7 downto 0);
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signal set_arp_entry_request : std_logic;
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signal set_mac5 : std_logic;
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signal set_mac4 : std_logic;
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signal set_mac3 : std_logic;
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signal set_mac2 : std_logic;
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signal set_mac1 : std_logic;
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signal set_mac0 : std_logic;
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signal set_ip3 : std_logic;
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signal set_ip2 : std_logic;
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signal set_ip1 : std_logic;
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signal set_ip0 : std_logic;
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-- tx control signals
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signal next_tx_state : tx_state_type;
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signal set_tx_state : std_logic;
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signal tx_count_mode : count_mode_type;
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signal clear_reply_req : std_logic;
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signal set_chn_reqd : set_clr_type;
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signal kill_data_out_valid : std_logic;
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-- function to determine whether the rx pkt is an arp pkt and whether we want to process it
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-- Returns 1 if we should discard
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-- The following will make us ignore the frame (all values hexadecimal):
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-- PDU type /= 0806
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-- Protocol Type /= 0800
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-- Hardware Type /= 1
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-- Hardware Length /= 6
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-- Protocol Length /= 4
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-- Operation /= 1 or 2
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-- Target IP /= our IP (i.er. message is not meant for us)
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--
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function not_our_arp(data : STD_LOGIC_VECTOR; count : unsigned; our_ip : std_logic_vector) return std_logic is
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begin
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if
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(count = 12 and data /= x"08") or -- PDU type 0806 : ARP
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(count = 13 and data /= x"06") or
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(count = 14 and data /= x"00") or -- HW type 1 : eth
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(count = 15 and data /= x"01") or
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(count = 16 and data /= x"08") or -- Protocol 0800 : IP
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(count = 17 and data /= x"00") or
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(count = 18 and data /= x"06") or -- HW Length 6
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(count = 19 and data /= x"04") or -- protocol length 4
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(count = 20 and data /= x"00") or -- operation 1 or 2 (req or reply)
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(count = 21 and data /= x"01" and data /= x"02") or
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(count = 38 and data /= our_ip(31 downto 24)) or -- target IP is ours
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(count = 39 and data /= our_ip(23 downto 16)) or
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(count = 40 and data /= our_ip(15 downto 8)) or
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(count = 41 and data /= our_ip(7 downto 0))
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then
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return '1';
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else
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return '0';
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end if;
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end function not_our_arp;
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begin
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req_combinatorial : process (
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-- input signals
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arp_req_req,
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-- state variables
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req_state, req_ip_addr, mac_addr_found, mac_addr_valid_reg, send_request_needed, arp_entry,
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-- control signals
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next_req_state, set_req_state, set_req_ip, set_mac_addr,set_mac_addr_invalid,set_send_req, clear_send_req)
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begin
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-- set output followers
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arp_req_rslt.got_err <= '0'; -- errors not returned in this version
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-- zero time response to lookup request if already in cache
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if arp_req_req.lookup_req = '1' and arp_req_req.ip = arp_entry.ip and arp_entry.is_valid = '1' then
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arp_req_rslt.got_mac <= '1';
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arp_req_rslt.mac <= arp_entry.mac;
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pjf |
elsif arp_req_req.lookup_req = '1' then
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arp_req_rslt.got_mac <= '0'; -- hold off got_mac while req is there as arp_entry will not be correct yet
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arp_req_rslt.mac <= arp_entry.mac;
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pjf |
else
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arp_req_rslt.got_mac <= mac_addr_valid_reg;
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arp_req_rslt.mac <= mac_addr_found;
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end if;
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-- set signal defaults
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next_req_state <= IDLE;
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set_req_state <= '0';
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set_req_ip <= '0';
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set_mac_addr <= '0';
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set_mac_addr_invalid <= '0';
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set_send_req <= '0';
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clear_send_req <= '0';
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-- REQ FSM
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case req_state is
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when IDLE =>
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if arp_req_req.lookup_req = '1' then
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-- check if we already have the info in cache
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if arp_req_req.ip = arp_entry.ip and arp_entry.is_valid = '1' then
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-- already have this IP
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set_mac_addr <= '1';
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else
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next_req_state <= LOOKUP;
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set_req_state <= '1';
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set_req_ip <= '1';
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set_mac_addr_invalid <= '1';
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end if;
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end if;
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when LOOKUP =>
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if arp_entry.ip = req_ip_addr and arp_entry.is_valid = '1' then
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-- already have this IP
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next_req_state <= IDLE;
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set_req_state <= '1';
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set_mac_addr <= '1';
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else
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-- need to request mac for this IP
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next_req_state <= REQUEST;
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set_req_state <= '1';
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set_send_req <= '1';
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end if;
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when REQUEST =>
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clear_send_req <= '1';
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next_req_state <= WAIT_REPLY;
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set_req_state <= '1';
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when WAIT_REPLY =>
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if arp_entry.is_valid = '1' then
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-- have reply, go back to LOOKUP state to see if it is the right one
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next_req_state <= LOOKUP;
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set_req_state <= '1';
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end if;
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-- TODO: add timeout here
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end case;
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end process;
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req_sequential : process (data_in_clk,reset)
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begin
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if rising_edge(data_in_clk) then
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if reset = '1' then
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-- reset state variables
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req_state <= IDLE;
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req_ip_addr <= (others => '0');
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mac_addr_found <= (others => '0');
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mac_addr_valid_reg <= '0';
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send_request_needed <= '0';
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else
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-- Next req_state processing
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if set_req_state = '1' then
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req_state <= next_req_state;
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else
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req_state <= req_state;
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end if;
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-- Latch the requested IP address
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if set_req_ip = '1' then
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req_ip_addr <= arp_req_req.ip;
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else
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req_ip_addr <= req_ip_addr;
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end if;
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-- send request to TX&RX FSMs to send an ARP request
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if set_send_req = '1' then
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send_request_needed <= '1';
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elsif clear_send_req = '1' then
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send_request_needed <= '0';
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else
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send_request_needed <= send_request_needed;
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end if;
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-- Set the found mac address
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if set_mac_addr = '1' then
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mac_addr_found <= arp_entry.mac;
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mac_addr_valid_reg <= '1';
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elsif set_mac_addr_invalid = '1' then
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mac_addr_found <= (others => '0');
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mac_addr_valid_reg <= '0';
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else
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mac_addr_found <= mac_addr_found;
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mac_addr_valid_reg <= mac_addr_valid_reg;
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end if;
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end if;
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end if;
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end process;
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rx_combinatorial : process (
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-- input signals
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data_in, data_in_valid, data_in_last, our_ip_address,
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-- state variables
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rx_state, rx_count, arp_operation, arp_req_count, arp_err_data,
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-- control signals
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next_rx_state, set_rx_state, rx_event, rx_count_mode, set_arp_oper, arp_oper_set_val,
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dataval,set_mac5,set_mac4,set_mac3,set_mac2,set_mac1,set_mac0,set_ip3,set_ip2,set_ip1,set_ip0, set_err_data,
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set_arp_entry_request)
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begin
|
| 319 |
|
|
-- set output followers
|
| 320 |
|
|
req_count <= STD_LOGIC_VECTOR(arp_req_count);
|
| 321 |
|
|
|
| 322 |
|
|
-- set signal defaults
|
| 323 |
|
|
next_rx_state <= IDLE;
|
| 324 |
|
|
set_rx_state <= '0';
|
| 325 |
|
|
rx_event <= NO_EVENT;
|
| 326 |
|
|
rx_count_mode <= HOLD;
|
| 327 |
|
|
set_arp_oper <= '0';
|
| 328 |
|
|
arp_oper_set_val <= NOP;
|
| 329 |
|
|
dataval <= (others => '0');
|
| 330 |
|
|
set_mac5 <= '0';
|
| 331 |
|
|
set_mac4 <= '0';
|
| 332 |
|
|
set_mac3 <= '0';
|
| 333 |
|
|
set_mac2 <= '0';
|
| 334 |
|
|
set_mac1 <= '0';
|
| 335 |
|
|
set_mac0 <= '0';
|
| 336 |
|
|
set_ip3 <= '0';
|
| 337 |
|
|
set_ip2 <= '0';
|
| 338 |
|
|
set_ip1 <= '0';
|
| 339 |
|
|
set_ip0 <= '0';
|
| 340 |
|
|
set_arp_entry_request <= '0';
|
| 341 |
|
|
set_err_data <= '0';
|
| 342 |
|
|
|
| 343 |
|
|
-- determine event (if any)
|
| 344 |
|
|
if data_in_valid = '1' then
|
| 345 |
|
|
rx_event <= DATA;
|
| 346 |
|
|
end if;
|
| 347 |
|
|
|
| 348 |
|
|
-- RX FSM
|
| 349 |
|
|
case rx_state is
|
| 350 |
|
|
when IDLE =>
|
| 351 |
|
|
rx_count_mode <= RST;
|
| 352 |
|
|
case rx_event is
|
| 353 |
|
|
when NO_EVENT => -- (nothing to do)
|
| 354 |
|
|
when DATA =>
|
| 355 |
|
|
next_rx_state <= PARSE;
|
| 356 |
|
|
set_rx_state <= '1';
|
| 357 |
|
|
rx_count_mode <= INCR;
|
| 358 |
|
|
end case;
|
| 359 |
|
|
|
| 360 |
|
|
when PARSE =>
|
| 361 |
|
|
case rx_event is
|
| 362 |
|
|
when NO_EVENT => -- (nothing to do)
|
| 363 |
|
|
when DATA =>
|
| 364 |
|
|
rx_count_mode <= INCR;
|
| 365 |
|
|
-- handle early frame termination
|
| 366 |
|
|
if data_in_last = '1' then
|
| 367 |
|
|
next_rx_state <= IDLE;
|
| 368 |
|
|
set_rx_state <= '1';
|
| 369 |
|
|
else
|
| 370 |
|
|
-- check for end of frame. Also, detect and discard if not our frame
|
| 371 |
|
|
if rx_count = 42 then
|
| 372 |
|
|
next_rx_state <= PROCESS_ARP;
|
| 373 |
|
|
set_rx_state <= '1';
|
| 374 |
|
|
elsif not_our_arp(data_in,rx_count,our_ip_address) = '1' then
|
| 375 |
|
|
dataval <= data_in;
|
| 376 |
|
|
set_err_data <= '1';
|
| 377 |
|
|
next_rx_state <= WAIT_END;
|
| 378 |
|
|
set_rx_state <= '1';
|
| 379 |
|
|
elsif rx_count = 21 then
|
| 380 |
|
|
-- capture ARP operation
|
| 381 |
|
|
case data_in is
|
| 382 |
|
|
when x"01" =>
|
| 383 |
|
|
arp_oper_set_val <= REQUEST;
|
| 384 |
|
|
set_arp_oper <= '1';
|
| 385 |
|
|
when x"02" =>
|
| 386 |
|
|
arp_oper_set_val <= REPLY;
|
| 387 |
|
|
set_arp_oper <= '1';
|
| 388 |
|
|
when others => -- ignore other values
|
| 389 |
|
|
end case;
|
| 390 |
|
|
-- capture source mac addr
|
| 391 |
|
|
elsif rx_count = 22 then
|
| 392 |
|
|
set_mac5 <= '1';
|
| 393 |
|
|
dataval <= data_in;
|
| 394 |
|
|
elsif rx_count = 23 then
|
| 395 |
|
|
set_mac4 <= '1';
|
| 396 |
|
|
dataval <= data_in;
|
| 397 |
|
|
elsif rx_count = 24 then
|
| 398 |
|
|
set_mac3 <= '1';
|
| 399 |
|
|
dataval <= data_in;
|
| 400 |
|
|
elsif rx_count = 25 then
|
| 401 |
|
|
set_mac2 <= '1';
|
| 402 |
|
|
dataval <= data_in;
|
| 403 |
|
|
elsif rx_count = 26 then
|
| 404 |
|
|
set_mac1 <= '1';
|
| 405 |
|
|
dataval <= data_in;
|
| 406 |
|
|
elsif rx_count = 27 then
|
| 407 |
|
|
set_mac0 <= '1';
|
| 408 |
|
|
dataval <= data_in;
|
| 409 |
|
|
-- capture source ip addr
|
| 410 |
|
|
elsif rx_count = 28 then
|
| 411 |
|
|
set_ip3 <= '1';
|
| 412 |
|
|
dataval <= data_in;
|
| 413 |
|
|
elsif rx_count = 29 then
|
| 414 |
|
|
set_ip2 <= '1';
|
| 415 |
|
|
dataval <= data_in;
|
| 416 |
|
|
elsif rx_count = 30 then
|
| 417 |
|
|
set_ip1 <= '1';
|
| 418 |
|
|
dataval <= data_in;
|
| 419 |
|
|
elsif rx_count = 31 then
|
| 420 |
|
|
set_ip0 <= '1';
|
| 421 |
|
|
dataval <= data_in;
|
| 422 |
|
|
end if;
|
| 423 |
|
|
end if;
|
| 424 |
|
|
end case;
|
| 425 |
|
|
|
| 426 |
|
|
when PROCESS_ARP =>
|
| 427 |
|
|
next_rx_state <= WAIT_END;
|
| 428 |
|
|
set_rx_state <= '1';
|
| 429 |
|
|
case arp_operation is
|
| 430 |
|
|
when NOP => -- (nothing to do)
|
| 431 |
|
|
when REQUEST =>
|
| 432 |
|
|
set_arp_entry_request <= '1';
|
| 433 |
|
|
arp_oper_set_val <= NOP;
|
| 434 |
|
|
set_arp_oper <= '1';
|
| 435 |
|
|
when REPLY =>
|
| 436 |
|
|
set_arp_entry_request <= '1';
|
| 437 |
|
|
arp_oper_set_val <= NOP;
|
| 438 |
|
|
set_arp_oper <= '1';
|
| 439 |
|
|
end case;
|
| 440 |
|
|
|
| 441 |
|
|
when WAIT_END =>
|
| 442 |
|
|
case rx_event is
|
| 443 |
|
|
when NO_EVENT => -- (nothing to do)
|
| 444 |
|
|
when DATA =>
|
| 445 |
|
|
if data_in_last = '1' then
|
| 446 |
|
|
next_rx_state <= IDLE;
|
| 447 |
|
|
set_rx_state <= '1';
|
| 448 |
|
|
end if;
|
| 449 |
|
|
end case;
|
| 450 |
|
|
|
| 451 |
|
|
end case;
|
| 452 |
|
|
|
| 453 |
|
|
end process;
|
| 454 |
|
|
|
| 455 |
|
|
rx_sequential : process (data_in_clk)
|
| 456 |
|
|
begin
|
| 457 |
|
|
if rising_edge(data_in_clk) then
|
| 458 |
|
|
if reset = '1' then
|
| 459 |
|
|
-- reset state variables
|
| 460 |
|
|
rx_state <= IDLE;
|
| 461 |
|
|
rx_count <= x"00";
|
| 462 |
|
|
arp_operation <= NOP;
|
| 463 |
|
|
arp_req_count <= x"00";
|
| 464 |
|
|
-- reset arp entry store
|
| 465 |
|
|
arp_entry.ip <= x"00000000";
|
| 466 |
|
|
arp_entry.mac <= x"000000000000";
|
| 467 |
|
|
arp_entry.is_valid <= '0';
|
| 468 |
|
|
arp_entry.reply_required <= '0';
|
| 469 |
|
|
arp_err_data <= (others => '0');
|
| 470 |
|
|
else
|
| 471 |
|
|
-- Next rx_state processing
|
| 472 |
|
|
if set_rx_state = '1' then
|
| 473 |
|
|
rx_state <= next_rx_state;
|
| 474 |
|
|
else
|
| 475 |
|
|
rx_state <= rx_state;
|
| 476 |
|
|
end if;
|
| 477 |
|
|
|
| 478 |
|
|
-- rx_count processing
|
| 479 |
|
|
case rx_count_mode is
|
| 480 |
|
|
when RST =>
|
| 481 |
|
|
rx_count <= x"00";
|
| 482 |
|
|
when INCR =>
|
| 483 |
|
|
rx_count <= rx_count + 1;
|
| 484 |
|
|
when HOLD =>
|
| 485 |
|
|
rx_count <= rx_count;
|
| 486 |
|
|
end case;
|
| 487 |
|
|
|
| 488 |
|
|
-- err data
|
| 489 |
|
|
if set_err_data = '1' then
|
| 490 |
|
|
arp_err_data <= data_in;
|
| 491 |
|
|
else
|
| 492 |
|
|
arp_err_data <= arp_err_data;
|
| 493 |
|
|
end if;
|
| 494 |
|
|
|
| 495 |
|
|
-- arp operation processing
|
| 496 |
|
|
if set_arp_oper = '1' then
|
| 497 |
|
|
arp_operation <= arp_oper_set_val;
|
| 498 |
|
|
else
|
| 499 |
|
|
arp_operation <= arp_operation;
|
| 500 |
|
|
end if;
|
| 501 |
|
|
|
| 502 |
|
|
-- source mac capture
|
| 503 |
|
|
if (set_mac5 = '1') then new_arp_entry.mac(47 downto 40) <= dataval; end if;
|
| 504 |
|
|
if (set_mac4 = '1') then new_arp_entry.mac(39 downto 32) <= dataval; end if;
|
| 505 |
|
|
if (set_mac3 = '1') then new_arp_entry.mac(31 downto 24) <= dataval; end if;
|
| 506 |
|
|
if (set_mac2 = '1') then new_arp_entry.mac(23 downto 16) <= dataval; end if;
|
| 507 |
|
|
if (set_mac1 = '1') then new_arp_entry.mac(15 downto 8) <= dataval; end if;
|
| 508 |
|
|
if (set_mac0 = '1') then new_arp_entry.mac(7 downto 0) <= dataval; end if;
|
| 509 |
|
|
|
| 510 |
|
|
-- source ip capture
|
| 511 |
|
|
if (set_ip3 = '1') then new_arp_entry.ip(31 downto 24) <= dataval; end if;
|
| 512 |
|
|
if (set_ip2 = '1') then new_arp_entry.ip(23 downto 16) <= dataval; end if;
|
| 513 |
|
|
if (set_ip1 = '1') then new_arp_entry.ip(15 downto 8) <= dataval; end if;
|
| 514 |
|
|
if (set_ip0 = '1') then new_arp_entry.ip(7 downto 0) <= dataval; end if;
|
| 515 |
|
|
|
| 516 |
|
|
-- set arp entry request
|
| 517 |
|
|
if set_arp_entry_request = '1' then
|
| 518 |
|
|
-- copy info from new entry to arp_entry and set reply required
|
| 519 |
|
|
arp_entry.mac <= new_arp_entry.mac;
|
| 520 |
|
|
arp_entry.ip <= new_arp_entry.ip;
|
| 521 |
|
|
arp_entry.is_valid <= '1';
|
| 522 |
|
|
if arp_operation = REQUEST then
|
| 523 |
|
|
arp_entry.reply_required <= '1';
|
| 524 |
|
|
else
|
| 525 |
|
|
arp_entry.reply_required <= '0';
|
| 526 |
|
|
end if;
|
| 527 |
|
|
-- count another ARP pkt received
|
| 528 |
|
|
arp_req_count <= arp_req_count + 1;
|
| 529 |
|
|
elsif clear_reply_req = '1' then
|
| 530 |
|
|
-- note: clear_reply_req is set by tx logic, but handled in the clk domain of the rx
|
| 531 |
|
|
-- maintain arp entry state, but reset the reply required flag
|
| 532 |
|
|
arp_entry.mac <= arp_entry.mac;
|
| 533 |
|
|
arp_entry.ip <= arp_entry.ip;
|
| 534 |
|
|
arp_entry.is_valid <= arp_entry.is_valid;
|
| 535 |
|
|
arp_entry.reply_required <= '0';
|
| 536 |
|
|
arp_req_count <= arp_req_count;
|
| 537 |
|
|
elsif send_request_needed = '1' then
|
| 538 |
|
|
-- set up the arp entry to take the request to be transmitted out by the TX FSM
|
| 539 |
|
|
arp_entry.ip <= req_ip_addr;
|
| 540 |
|
|
arp_entry.mac <= (others => '0');
|
| 541 |
|
|
arp_entry.is_valid <= '0';
|
| 542 |
|
|
arp_entry.reply_required <= '0';
|
| 543 |
|
|
else
|
| 544 |
|
|
arp_entry <= arp_entry;
|
| 545 |
|
|
arp_req_count <= arp_req_count;
|
| 546 |
|
|
end if;
|
| 547 |
|
|
|
| 548 |
|
|
end if;
|
| 549 |
|
|
end if;
|
| 550 |
|
|
end process;
|
| 551 |
|
|
|
| 552 |
|
|
tx_combinatorial : process (
|
| 553 |
|
|
-- input signals
|
| 554 |
|
|
data_out_ready, send_request_needed, mac_tx_granted, our_mac_address, our_ip_address,
|
| 555 |
|
|
-- state variables
|
| 556 |
|
|
tx_state, tx_count, tx_mac_chn_reqd, arp_entry,
|
| 557 |
|
|
-- control signals
|
| 558 |
|
|
next_rx_state, set_rx_state, tx_count_mode, kill_data_out_valid,
|
| 559 |
|
|
set_chn_reqd, clear_reply_req)
|
| 560 |
|
|
begin
|
| 561 |
|
|
-- set output followers
|
| 562 |
4 |
pjf |
mac_tx_req <= tx_mac_chn_reqd;
|
| 563 |
2 |
pjf |
|
| 564 |
4 |
pjf |
-- set initial values for combinatorial outputs
|
| 565 |
|
|
data_out_first <= '0';
|
| 566 |
|
|
|
| 567 |
2 |
pjf |
case tx_state is
|
| 568 |
|
|
when SEND =>
|
| 569 |
|
|
if data_out_ready = '1' and kill_data_out_valid = '0' then
|
| 570 |
|
|
data_out_valid <= '1';
|
| 571 |
|
|
else
|
| 572 |
|
|
data_out_valid <= '0';
|
| 573 |
|
|
end if;
|
| 574 |
|
|
when OTHERS => data_out_valid <= '0';
|
| 575 |
|
|
end case;
|
| 576 |
|
|
|
| 577 |
|
|
-- set signal defaults
|
| 578 |
|
|
next_tx_state <= IDLE;
|
| 579 |
|
|
set_tx_state <= '0';
|
| 580 |
|
|
tx_count_mode <= HOLD;
|
| 581 |
|
|
data_out <= x"00";
|
| 582 |
|
|
data_out_last <= '0';
|
| 583 |
|
|
clear_reply_req <= '0';
|
| 584 |
|
|
set_chn_reqd <= HOLD;
|
| 585 |
|
|
kill_data_out_valid <= '0';
|
| 586 |
|
|
|
| 587 |
|
|
-- TX FSM
|
| 588 |
|
|
case tx_state is
|
| 589 |
|
|
when IDLE =>
|
| 590 |
|
|
tx_count_mode <= RST;
|
| 591 |
|
|
if arp_entry.reply_required = '1' then
|
| 592 |
|
|
set_chn_reqd <= SET;
|
| 593 |
|
|
next_tx_state <= WAIT_MAC;
|
| 594 |
|
|
set_tx_state <= '1';
|
| 595 |
|
|
elsif send_request_needed = '1' then
|
| 596 |
|
|
set_chn_reqd <= SET;
|
| 597 |
|
|
next_tx_state <= WAIT_MAC;
|
| 598 |
|
|
set_tx_state <= '1';
|
| 599 |
|
|
else
|
| 600 |
|
|
set_chn_reqd <= CLR;
|
| 601 |
|
|
end if;
|
| 602 |
|
|
|
| 603 |
|
|
when WAIT_MAC =>
|
| 604 |
|
|
tx_count_mode <= RST;
|
| 605 |
|
|
if mac_tx_granted = '1' then
|
| 606 |
|
|
next_tx_state <= SEND;
|
| 607 |
|
|
set_tx_state <= '1';
|
| 608 |
|
|
end if;
|
| 609 |
|
|
-- TODO - should handle timeout here
|
| 610 |
|
|
|
| 611 |
|
|
when SEND =>
|
| 612 |
|
|
if data_out_ready = '1' then
|
| 613 |
|
|
tx_count_mode <= INCR;
|
| 614 |
|
|
end if;
|
| 615 |
|
|
case tx_count is
|
| 616 |
4 |
pjf |
when x"00" =>
|
| 617 |
|
|
data_out_first <= data_out_ready;
|
| 618 |
|
|
data_out <= x"ff"; -- dst = broadcast
|
| 619 |
|
|
|
| 620 |
2 |
pjf |
when x"01" => data_out <= x"ff";
|
| 621 |
|
|
when x"02" => data_out <= x"ff";
|
| 622 |
|
|
when x"03" => data_out <= x"ff";
|
| 623 |
|
|
when x"04" => data_out <= x"ff";
|
| 624 |
|
|
when x"05" => data_out <= x"ff";
|
| 625 |
|
|
when x"06" => data_out <= our_mac_address (47 downto 40); -- src = our mac
|
| 626 |
|
|
when x"07" => data_out <= our_mac_address (39 downto 32);
|
| 627 |
|
|
when x"08" => data_out <= our_mac_address (31 downto 24);
|
| 628 |
|
|
when x"09" => data_out <= our_mac_address (23 downto 16);
|
| 629 |
|
|
when x"0a" => data_out <= our_mac_address (15 downto 8);
|
| 630 |
|
|
when x"0b" => data_out <= our_mac_address (7 downto 0);
|
| 631 |
|
|
when x"0c" => data_out <= x"08"; -- pkt type = 0806 : ARP
|
| 632 |
|
|
when x"0d" => data_out <= x"06";
|
| 633 |
|
|
when x"0e" => data_out <= x"00"; -- HW type = 0001 : eth
|
| 634 |
|
|
when x"0f" => data_out <= x"01";
|
| 635 |
|
|
when x"10" => data_out <= x"08"; -- protocol = 0800 : ip
|
| 636 |
|
|
when x"11" => data_out <= x"00";
|
| 637 |
|
|
when x"12" => data_out <= x"06"; -- HW size = 06
|
| 638 |
|
|
when x"13" => data_out <= x"04"; -- prot size = 04
|
| 639 |
|
|
|
| 640 |
|
|
when x"14" => data_out <= x"00"; -- opcode =
|
| 641 |
|
|
when x"15" =>
|
| 642 |
|
|
if arp_entry.is_valid = '1' then
|
| 643 |
|
|
data_out <= x"02"; -- 02 : REPLY if arp_entry valid
|
| 644 |
|
|
else
|
| 645 |
|
|
data_out <= x"01"; -- 01 : REQ if arp_entry invalid
|
| 646 |
|
|
end if;
|
| 647 |
|
|
|
| 648 |
|
|
when x"16" => data_out <= our_mac_address (47 downto 40); -- sender mac
|
| 649 |
|
|
when x"17" => data_out <= our_mac_address (39 downto 32);
|
| 650 |
|
|
when x"18" => data_out <= our_mac_address (31 downto 24);
|
| 651 |
|
|
when x"19" => data_out <= our_mac_address (23 downto 16);
|
| 652 |
|
|
when x"1a" => data_out <= our_mac_address (15 downto 8);
|
| 653 |
|
|
when x"1b" => data_out <= our_mac_address (7 downto 0);
|
| 654 |
|
|
when x"1c" => data_out <= our_ip_address (31 downto 24); -- sender ip
|
| 655 |
|
|
when x"1d" => data_out <= our_ip_address (23 downto 16);
|
| 656 |
|
|
when x"1e" => data_out <= our_ip_address (15 downto 8);
|
| 657 |
|
|
when x"1f" => data_out <= our_ip_address (7 downto 0);
|
| 658 |
|
|
when x"20" => data_out <= arp_entry.mac (47 downto 40); -- target mac
|
| 659 |
|
|
when x"21" => data_out <= arp_entry.mac (39 downto 32);
|
| 660 |
|
|
when x"22" => data_out <= arp_entry.mac (31 downto 24);
|
| 661 |
|
|
when x"23" => data_out <= arp_entry.mac (23 downto 16);
|
| 662 |
|
|
when x"24" => data_out <= arp_entry.mac (15 downto 8);
|
| 663 |
|
|
when x"25" => data_out <= arp_entry.mac (7 downto 0);
|
| 664 |
|
|
when x"26" => data_out <= arp_entry.ip (31 downto 24); -- target ip
|
| 665 |
|
|
when x"27" => data_out <= arp_entry.ip (23 downto 16);
|
| 666 |
|
|
when x"28" => data_out <= arp_entry.ip (15 downto 8);
|
| 667 |
|
|
|
| 668 |
|
|
when x"29" =>
|
| 669 |
|
|
data_out <= arp_entry.ip(7 downto 0);
|
| 670 |
|
|
data_out_last <= '1';
|
| 671 |
|
|
|
| 672 |
|
|
when x"2a" =>
|
| 673 |
|
|
clear_reply_req <= '1'; -- reset the reply request (done in the rx clk process domain)
|
| 674 |
|
|
kill_data_out_valid <= '1'; -- data is no longer valid
|
| 675 |
|
|
next_tx_state <= IDLE;
|
| 676 |
|
|
set_tx_state <= '1';
|
| 677 |
|
|
|
| 678 |
|
|
when others =>
|
| 679 |
|
|
next_tx_state <= IDLE;
|
| 680 |
|
|
set_tx_state <= '1';
|
| 681 |
|
|
end case;
|
| 682 |
|
|
end case;
|
| 683 |
|
|
end process;
|
| 684 |
|
|
|
| 685 |
|
|
tx_sequential : process (data_out_clk,reset)
|
| 686 |
|
|
begin
|
| 687 |
|
|
if rising_edge(data_out_clk) then
|
| 688 |
|
|
if reset = '1' then
|
| 689 |
|
|
-- reset state variables
|
| 690 |
|
|
tx_state <= IDLE;
|
| 691 |
|
|
tx_mac_chn_reqd <= '0';
|
| 692 |
|
|
else
|
| 693 |
|
|
-- Next rx_state processing
|
| 694 |
|
|
if set_tx_state = '1' then
|
| 695 |
|
|
tx_state <= next_tx_state;
|
| 696 |
|
|
else
|
| 697 |
|
|
tx_state <= tx_state;
|
| 698 |
|
|
end if;
|
| 699 |
|
|
|
| 700 |
|
|
-- tx_count processing
|
| 701 |
|
|
case tx_count_mode is
|
| 702 |
|
|
when RST =>
|
| 703 |
|
|
tx_count <= x"00";
|
| 704 |
|
|
when INCR =>
|
| 705 |
|
|
tx_count <= tx_count + 1;
|
| 706 |
|
|
when HOLD =>
|
| 707 |
|
|
tx_count <= tx_count;
|
| 708 |
|
|
end case;
|
| 709 |
|
|
|
| 710 |
|
|
-- control access request to mac tx chn
|
| 711 |
|
|
case set_chn_reqd is
|
| 712 |
|
|
when SET => tx_mac_chn_reqd <= '1';
|
| 713 |
|
|
when CLR => tx_mac_chn_reqd <= '0';
|
| 714 |
|
|
when HOLD => tx_mac_chn_reqd <= tx_mac_chn_reqd;
|
| 715 |
|
|
end case;
|
| 716 |
|
|
|
| 717 |
|
|
end if;
|
| 718 |
|
|
end if;
|
| 719 |
|
|
end process;
|
| 720 |
|
|
|
| 721 |
|
|
|
| 722 |
|
|
end Behavioral;
|
| 723 |
|
|
|
