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.axiTransactor.all;

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

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

entity axiBfmMaster is

        port(aclk,n_areset:in std_ulogic;

                /* BFM signalling. */

                readRequest,writeRequest:in t_bfm:=(address=>(others=>'X'), message=>(others=>'X'), trigger=>false);

                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;

                lastTransaction:in boolean;

                /* 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;

        signal i_axiMaster_out:t_axi4StreamTransactor_m2s;

        signal i_trigger,trigger:boolean;

        /* BFM signalling. */

--      signal i_readRequest,i_writeRequest:t_bfm:=(address=>(others=>'X'),message=>(others=>'X'),trigger=>false);

--      signal i_readResponse,i_writeResponse:t_bfm;

        signal i_writeRequest:t_bfm:=(address=>(others=>'X'),message=>(others=>'X'),trigger=>false);

        signal i_writeResponse:t_bfm;

        /* DDR Pipelines. */

        signal next_axiTxState_rise,next_axiTxState_fall:axiBfmStatesTx;

        signal i_writeRequest_rise,i_writeRequest_fall:t_bfm;

        signal writeResponse_rise,writeResponse_fall:t_bfm;

        signal axiMaster_out_rise,axiMaster_out_fall:t_axi4StreamTransactor_m2s;

        signal trigger_rise,trigger_fall:boolean;

begin

        i_trigger<=writeRequest.trigger xor i_writeRequest.trigger;

        /* 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;

                else

                        case next_axiTxState is

                                when idle=>

                                        if i_trigger then axiTxState<=payload; end if;

                                when payload=>

                                        if lastTransaction then axiTxState<=endOfTx; end if;

                                when endOfTx=>

                                        if axiMaster_in.tReady then axiTxState<=idle; end if;

                                when others=>axiTxState<=idle;

                        end case;

                end if;

        end process axi_bfmTx_ns;

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

        axi_bfmTx_op: process(all) is begin

                i_writeResponse<=writeResponse;

                i_axiMaster_out<=axiMaster_out;

                i_axiMaster_out.tLast<=false;

                i_writeResponse.trigger<=false;

                case next_axiTxState is

                        when idle=>

                                i_axiMaster_out.tValid<=false;

                                i_axiMaster_out.tData<=(others=>'Z');

                                if i_trigger then

                                        i_axiMaster_out.tData<=writeRequest.message;

                                        i_axiMaster_out.tValid<=true;

                                end if;

                        when payload | endOfTx =>

                                if i_trigger then

                                        i_axiMaster_out.tData<=writeRequest.message;

                                        i_axiMaster_out.tValid<=true;

                                end if;

                                if axiMaster_in.tReady then

                                        i_writeResponse.trigger<=true;

                                end if;

                                if lastTransaction then i_axiMaster_out.tLast<=true; end if;

                        when others=> null;

                end case;

        end process axi_bfmTx_op;

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

        process(aclk) is begin

                if not n_areset then

                        next_axiTxState<=idle;

                        i_writeRequest<=(address=>(others=>'0'),message=>(others=>'0'),trigger=>false);

                        writeResponse<=(address=>(others=>'0'),message=>(others=>'0'),trigger=>false);

                        --axiMaster_out<=(others=>'0');

                        trigger<=false;

--              elsif rising_edge(aclk) then

--                      next_axiTxState<=axiTxState;

--                      i_writeRequest<=writeRequest;

--                      writeResponse<=i_writeResponse;

--                      axiMaster_out<=i_axiMaster_out;

--                      trigger<=i_trigger;

                elsif falling_edge(aclk) then

                        next_axiTxState<=axiTxState;

                        i_writeRequest<=writeRequest;

                        writeResponse<=i_writeResponse;

                        axiMaster_out<=i_axiMaster_out;

                        trigger<=i_trigger;

                end if;

        end process;

        /*

        process(n_areset,aclk) is begin

                if not n_areset then

                        next_axiTxState_rise<=idle;

                elsif rising_edge(aclk) then

                        next_axiTxState_rise<=axiTxState;

                        i_writeRequest_rise<=writeRequest;

                        writeResponse_rise<=i_writeResponse;

                        axiMaster_out_rise<=i_axiMaster_out;

                        trigger_rise<=i_trigger;

                end if;

        end process;

        process(n_areset,aclk) is begin

                if not n_areset then

                        next_axiTxState_fall<=idle;

                elsif falling_edge(aclk) then

                        next_axiTxState_fall<=axiTxState;

                        i_writeRequest_fall<=writeRequest;

                        writeResponse_fall<=i_writeResponse;

                        axiMaster_out_fall<=i_axiMaster_out;

                        trigger_fall<=i_trigger;

                end if;

        end process;

        next_axiTxState<=idle when not n_areset else next_axiTxState_rise xor next_axiTxState_fall;

        */

--      pseudo dual-edge-triggered D-Flip-Flop (Refer Ralf Hildebrant's paper: http://www.ralf-hildebrandt.de/publication/pdf_dff/pde_dff.pdf).

        /*

        process(async_clr,clk)

        begin

                if impl_rp=0 and async_clr='0' then ff_rise<='0';

                elsif impl_rp=1 and async_clr='0' then ff_rise<='1';

                elsif rising_edge(clk) then

                        if d='1' then ff_rise<=not ff_fall;

                        else ff_rise<=ff_fall;

                        end if;

                end if;

        end process;

        process(async_clr,clk)

        begin

                if impl_rp=0 and async_clr='0' then ff_fall<='0';

                elsif impl_rp=1 and async_clr='0' then ff_fall<='1';

                elsif falling_edge(clk) then

                        if d='1' then ff_fall<=not ff_rise;

                        else ff_fall<=ff_rise;

                        end if;

                end if;

        end process;

        q<='0' when impl_rp=0 and async_clr='0' else

                '1' when impl_rp=1 and async_clr='0' else

                ff_rise xor ff_fall;

        */

-- end pseudo dual-edge-triggered DFF

/*

--      process(n_areset,aclk) is

        process(aclk) is

--              variable q1,q2:std_ulogic_vector(q'length-1 downto 0);

                variable q_a1,q_a2:axiBfmStatesTx;              --std_ulogic_vector(axiTxState'range);

                variable q_b1,q_b2:t_bfm;                               --std_ulogic_vector(writeRequest'range);

                variable q_c1,q_c2:t_bfm;

                variable q_d1,q_d2:t_axi4StreamTransactor_m2s;

                variable q_e1,q_e2:boolean;

        begin

--              if not n_areset then

--                      q_a1:=idle; q_a2:=idle;

--                      q_b1:=(others=>'0'); q_b2:=(others=>'0');

--                      q_c1:=(others=>'0'); q_c2:=(others=>'0');

--                      q_d1:=(others=>'0'); q_d2:=(others=>'0');

--                      q_e1:=(others=>'0'); q_e2:=(others=>'0');

                if rising_edge(aclk) then

                        q_a1:=axiTxState xor q_a2;

                        q_b1:=writeRequest xor q_b2;

                        q_c1:=i_writeResponse xor q_c2;

                        q_d1:=i_axiMaster_out xor q_d2;

                        q_e1:=i_trigger xor q_e2;

                elsif falling_edge(aclk) then

                        q_a2:=axiTxState xor q_a1;

                        q_b2:=writeRequest xor q_b1;

                        q_c2:=i_writeResponse xor q_c1;

                        q_d2:=i_axiMaster_out xor q_d1;

                        q_e2:=i_trigger xor q_e1;

                end if;

                next_axiTxState<=q_a1 xor q_a2;

                i_writeRequest<=q_b1 xor q_b2;

                writeResponse<=q_c1 xor q_c2;

                axiMaster_out<=q_d1 xor q_d2;

                trigger<=q_e1 xor q_e2;

        end process;

*/

        dbg_axiTxFSM<=axiTxState;

end architecture rtl;