Subversion Repositories axi4_tlm_bfm

/*

        This file is part of the AXI4 Transactor and Bus Functional Model

        (axi4_tlm_bfm) project:

                http://www.opencores.org/project,axi4_tlm_bfm

        Description

        Implementation of AXI4 Master BFM core according to AXI4 protocol

        specification document.

        To Do: Implement AXI4-Lite and full AXI4 protocols.

        Author(s):

        - Daniel C.K. Kho, daniel.kho@opencores.org | daniel.kho@tauhop.com

        Copyright (C) 2012-2013 Authors and OPENCORES.ORG

        This source file may be used and distributed without

        restriction provided that this copyright statement is not

        removed from the file and that any derivative work contains

        the original copyright notice and the associated disclaimer.

        This source file is free software; you can redistribute it

        and/or modify it under the terms of the GNU Lesser General

        Public License as published by the Free Software Foundation;

        either version 2.1 of the License, or (at your option) any

        later version.

        This source is distributed in the hope that it will be

        useful, but WITHOUT ANY WARRANTY; without even the implied

        warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR

        PURPOSE. See the GNU Lesser General Public License for more

        details.

        You should have received a copy of the GNU Lesser General

        Public License along with this source; if not, download it

        from http://www.opencores.org/lgpl.shtml.

*/

library ieee; use ieee.std_logic_1164.all, ieee.numeric_std.all;

--library tauhop; use tauhop.transactor.all, tauhop.axiTransactor.all;

/* TODO remove once generic packages are supported. */

library tauhop; use tauhop.tlm.all, tauhop.axiTLM.all;

entity axiBfmMaster is --generic(constant maxTransactions:positive);

        port(aclk,n_areset:in std_ulogic;

                /* User trigger. */

                trigger:in boolean;

                /* BFM signalling. */

                readRequest,writeRequest:in t_bfm:=((others=>'X'),(others=>'X'),false); -- this is tauhop.transactor.t_bfm.

                readResponse,writeResponse:buffer t_bfm;                                                                        -- use buffer until synthesis tools support reading from out ports.

                /* AXI Master interface */

                axiMaster_in:in t_axi4StreamTransactor_s2m;

                axiMaster_out:buffer t_axi4StreamTransactor_m2s;

--              /* AXI Slave interface */

--              axiSlave_in:in tAxi4Transactor_m2s;

--              axiSlave_out:buffer tAxi4Transactor_s2m;

                symbolsPerTransfer:in t_cnt;

                outstandingTransactions:buffer t_cnt

                /* Debug ports. */

--              dbg_cnt:out unsigned(9 downto 0);

--              dbg_axiRxFsm:out axiBfmStatesRx:=idle;

--              dbg_axiTxFsm:out axiBfmStatesTx:=idle

        );

end entity axiBfmMaster;

architecture rtl of axiBfmMaster is

        /* Finite-state Machines. */

        signal axiTxState,next_axiTxState:axiBfmStatesTx:=idle;

        /* General pipelines. */

        signal i_axiMaster_out:t_axi4StreamTransactor_m2s;

        /* BFM signalling. */

        signal i_readRequest:t_bfm:=((others=>'0'),(others=>'0'),false);

        signal i_writeRequest:t_bfm:=((others=>'0'),(others=>'0'),false);

        signal response,i_response:boolean;

begin

        /* Transaction counter. */

        process(n_areset,symbolsPerTransfer,aclk) is begin

                if not n_areset then outstandingTransactions<=symbolsPerTransfer;

                elsif rising_edge(aclk) then

                        if outstandingTransactions>0 then outstandingTransactions<=outstandingTransactions-1;

                        else

                                outstandingTransactions<=symbolsPerTransfer;

                                report "No more pending transactions." severity note;

                        end if;

                end if;

        end process;

        /* next-state logic for AXI4-Stream Master Tx BFM. */

        axi_bfmTx_ns: process(all) is begin

                axiTxState<=next_axiTxState;

                if not n_areset then axiTxState<=idle;

                elsif writeRequest.trigger xor i_writeRequest.trigger then axiTxState<=payload;

                end if;

                case next_axiTxState is

                        when idle=>null;

                        when payload=>

                                if outstandingTransactions<1 then axiTxState<=idle; end if;

                        when others=>axiTxState<=idle;

                end case;

        end process axi_bfmTx_ns;

        /* output logic for AXI4-Stream Master Tx BFM. */

        axi_bfmTx_op: process(all) is begin

                axiMaster_out<=i_axiMaster_out;

                case next_axiTxState is

                        when payload=>

                                axiMaster_out.tValid<=true;

                                if axiMaster_in.tReady then

                                        axiMaster_out.tData<=writeRequest.message;

                                end if;

                        when others=> axiMaster_out.tValid<=false; axiMaster_out.tData<=(others=>'Z');          --TODO: set 'Z' to '0' for synthesis.

                end case;

        end process axi_bfmTx_op;

        /* state registers and pipelines for AXI4-Stream Tx BFM. */

        process(n_areset,aclk) is begin

                if not n_areset then next_axiTxState<=idle;

                elsif rising_edge(aclk) then

                        next_axiTxState<=axiTxState;

                        i_axiMaster_out<=axiMaster_out;

                        i_writeRequest<=writeRequest;

                end if;

        end process;

--      dbg_axiTxFsm<=axiTxState;

end architecture rtl;