Subversion Repositories mips_enhanced

------------------------------------------------------------------------------

--  This file is a part of the GRLIB VHDL IP LIBRARY

--  Copyright (C) 2003, Gaisler Research

--

--  This program is free software; you can redistribute it and/or modify

--  it under the terms of the GNU General Public License as published by

--  the Free Software Foundation; either version 2 of the License, or

--  (at your option) any later version.

--

--  This program 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 General Public License for more details.

--

--  You should have received a copy of the GNU General Public License

--  along with this program; if not, write to the Free Software

--  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA 

-----------------------------------------------------------------------------   

-- Entity:      can_oc

-- File:        can_oc.vhd

-- Author:      Jiri Gaisler - Gaisler Research

-- Description: AHB interface for the OpenCores CAN MAC

------------------------------------------------------------------------------ 

library ieee;

use ieee.std_logic_1164.all;

library grlib;

use grlib.amba.all;

use grlib.stdlib.all;

use grlib.devices.all;

library techmap;

use techmap.gencomp.all;

library gaisler;

use gaisler.can.all;

entity can_rd is

   generic (

    slvndx    : integer := 0;

    ioaddr    : integer := 16#000#;

    iomask    : integer := 16#FF0#;

    irq       : integer := 0;

    memtech   : integer := DEFMEMTECH;

    syncrst   : integer := 0;

    dmap      : integer := 0);

   port (

      resetn  : in  std_logic;

      clk     : in  std_logic;

      ahbsi   : in  ahb_slv_in_type;

      ahbso   : out ahb_slv_out_type;

      can_rxi : in  std_logic_vector(1 downto 0);

      can_txo : out std_logic_vector(1 downto 0)

   );

end;

architecture rtl of can_rd is

constant ncores : integer := 1;

constant sepirq : integer := 0;

constant REVISION : amba_version_type := ncores-1;

constant hconfig : ahb_config_type := (

  4 => ahb_iobar(ioaddr, iomask), others => zero32);

type ahbregs is record

  hsel      : std_ulogic;

  hwrite    : std_ulogic;

  hwrite2   : std_ulogic;

  htrans    : std_logic_vector(1 downto 0);

  haddr     : std_logic_vector(10 downto 0);

  hwdata    : std_logic_vector(7 downto 0);

  herr      : std_ulogic;

  hready    : std_ulogic;

  ws        : std_logic_vector(1 downto 0);

  irqi      : std_logic_vector(ncores-1 downto 0);

  irqo      : std_logic_vector(ncores-1 downto 0);

  muxsel    : std_logic;

  writemux  : std_logic;

end record;

subtype cdata is std_logic_vector(7 downto 0);

type cdataarr is array (0 to 7) of cdata;

signal data_out : cdataarr;

signal reset : std_logic;

signal irqo : std_logic_vector(ncores-1 downto 0);

signal addr : std_logic_vector(7 downto 0);

signal vcc, gnd : std_ulogic;

signal r, rin : ahbregs;

signal can_lrxi, can_ltxo : std_logic;

begin

  gnd <= '0'; vcc <= '1'; reset <= not resetn;

  comb : process(ahbsi, r, resetn, data_out, irqo)

  variable v : ahbregs;

  variable hresp : std_logic_vector(1 downto 0);

  variable dataout : std_logic_vector(7 downto 0);

  variable irqvec : std_logic_vector(NAHBIRQ-1 downto 0);

  variable vmuxreg : std_logic;

  begin

    v := r;

    if (r.hsel = '1' ) and (r.ws /= "11") then v.ws := r.ws + 1; end if;

    if ahbsi.hready = '1' then

      v.hsel := ahbsi.hsel(slvndx);

      v.haddr := ahbsi.haddr(10 downto 0);

      v.htrans := ahbsi.htrans;

      v.hwrite := ahbsi.hwrite;

      v.herr := orv(ahbsi.hsize) and ahbsi.hwrite;

      v.ws := "00";

    end if;

    v.hready := (r.hsel and r.ws(1) and not r.ws(0)) or not resetn

        or (ahbsi.hready and not ahbsi.htrans(1));

    vmuxreg := not r.haddr(7) and r.haddr(6);

    --v.hwrite2 := r.hwrite and r.hsel and r.htrans(1) and r.ws(1) 

--      and not r.ws(0) and not r.herr;

    v.hwrite2 := r.hwrite and r.hsel and r.htrans(1) and r.ws(1)

        and not r.ws(0) and not r.herr and not vmuxreg;

    v.writemux := r.hwrite and r.hsel and r.htrans(1) and r.ws(1)

        and not r.ws(0) and vmuxreg;

    if (r.herr and r.ws(1)) = '1' then hresp := HRESP_ERROR;

    else hresp := HRESP_OKAY; end if;

    case r.haddr(1 downto 0) is

    when "00" => v.hwdata := ahbsi.hwdata(31 downto 24);

    when "01" => v.hwdata := ahbsi.hwdata(23 downto 16);

    when "10" => v.hwdata := ahbsi.hwdata(15 downto 8);

    when others => v.hwdata := ahbsi.hwdata(7 downto 0);

    end case;

    --dataout := data_out(0);

    if r.haddr(7 downto 6) = "01" then

       dataout := (others => r.muxsel);

       if r.writemux = '1' then

          v.muxsel := r.hwdata(0);

       end if;

    else

       dataout := data_out(0);

    end if;

    -- Interrupt goes to low when appeard and is normal high

    -- but the irq controller from leon is active high and the interrupt should appear only

    -- for 1 Clk cycle,

    v.irqi := irqo; v.irqo:= (r.irqi and not irqo);

    irqvec := (others => '0');

    if sepirq = 1 then irqvec(ncores-1+irq downto irq) := r.irqo;

    else irqvec(irq) := orv(r.irqo); end if;

    ahbso.hirq <= irqvec;

    ahbso.hrdata  <= dataout & dataout & dataout & dataout;

    ahbso.hresp <= hresp; rin <= v;

  end process;

  -- Double mapping of registers [byte (offset 0), word (offset 0x80)]

  dmap0 : if dmap = 0 generate

    addr <= r.haddr(7 downto 0);

  end generate;

  dmap1 : if dmap = 1 generate

    addr <= "000"&r.haddr(6 downto 2) when r.haddr(7) = '1' else

            r.haddr(7 downto 0);

  end generate;

  reg : process(clk)

  begin if clk'event and clk = '1' then r <= rin; end if; end process;

  cmod : can_mod generic map (memtech, syncrst)

    --port map (reset, clk, r.hsel, r.hwrite2, r.haddr(7 downto 0), r.hwdata, 

    port map (reset, clk, r.hsel, r.hwrite2, addr, r.hwdata,

        data_out(0), irqo(0), can_lrxi, can_ltxo, ahbsi.testen);

  cmux : canmux port map (r.muxsel, can_lrxi, can_ltxo, can_rxi, can_txo);

    ahbso.hconfig <= hconfig;

    ahbso.hindex  <= slvndx;

    ahbso.hsplit  <= (others => '0');

    ahbso.hcache  <= '0';

    ahbso.hready  <= r.hready;

-- pragma translate_off

  bootmsg : report_version

  generic map (

        "can_oc" & tost(slvndx) &

        ": SJA1000 Compatible CAN MAC, revision " & tost(REVISION) &

        ", irq " & tost(irq));

-- pragma translate_on

end;