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 

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

library ieee;

library grlib;

library gaisler;

use ieee.std_logic_1164.all;

use grlib.amba.all;

use grlib.stdlib.all;

use grlib.devices.all;

use gaisler.misc.all;

entity ahbstat is

  generic(

    pindex : integer := 0;

    paddr  : integer := 0;

    pmask  : integer := 16#FFF#;

    pirq   : integer := 0;

    nftslv : integer range 1 to NAHBSLV - 1 := 3);

  port(

    rst   : in std_ulogic;

    clk   : in std_ulogic;

    ahbmi : in ahb_mst_in_type;

    ahbsi : in ahb_slv_in_type;

    stati : in ahbstat_in_type;

    apbi  : in apb_slv_in_type;

    apbo  : out apb_slv_out_type

  );

end entity;

architecture rtl of ahbstat is

  type reg_type is record

    addr    : std_logic_vector(31 downto 0); --failing address

    hsize   : std_logic_vector(2 downto 0);  --ahb signals for failing op.

    hmaster : std_logic_vector(3 downto 0);

    hwrite  : std_ulogic;

    hresp   : std_logic_vector(1 downto 0);

    newerr  : std_ulogic; --new error detected

    cerror  : std_ulogic; --correctable error detected

    pirq    : std_ulogic;

  end record;

  signal r, rin : reg_type;

  constant VERSION : integer := 0;

  constant pconfig : apb_config_type := (

  1 => apb_iobar(paddr, pmask));

begin

  comb : process(rst, ahbmi, ahbsi, stati, apbi, r) is

  variable v       : reg_type;

  variable prdata  : std_logic_vector(31 downto 0);

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

  variable ce      : std_ulogic; --correctable error

  begin

    v := r; vpirq := (others => '0'); prdata := (others => '0'); v.pirq := '0';

    ce := orv(stati.cerror(0 to nftslv-1));

    case apbi.paddr(2) is

    when '0' => --status values

      prdata(2 downto 0) := r.hsize;

      prdata(6 downto 3) := r.hmaster;

      prdata(7) := r.hwrite;

      prdata(8) := r.newerr;

      prdata(9) := r.cerror;

    when others => --failing address

      prdata := r.addr;

    end case;

    --writes. data is written in setup cycle so that r.newerr is updated

    --when hready = '1'

    if (apbi.psel(pindex) and not apbi.penable and apbi.pwrite) = '1' then

      case apbi.paddr(2) is

      when '0' =>

        v.newerr := apbi.pwdata(8);

        v.cerror := apbi.pwdata(9);

      when others => null;

      end case;

    end if;

    v.hresp := ahbmi.hresp;

    if (ahbsi.hready = '1') and  (r.newerr = '0') then

      if (r.hresp = HRESP_ERROR) or (ce = '1') then v.newerr := '1';

        v.cerror := ce;

      else

        v.addr := ahbsi.haddr;

        v.hsize := ahbsi.hsize;

        v.hmaster := ahbsi.hmaster;

        v.hwrite := ahbsi.hwrite;

      end if;

    end if;

    --irq generation

    v.pirq := v.newerr and not r.newerr;

    vpirq(pirq) := r.pirq;

    --reset

    if rst = '0' then

      v.newerr := '0'; v.cerror := '0';

    end if;

    rin <= v;

    apbo.prdata <= prdata;

    apbo.pirq <= vpirq;

  end process;

  apbo.pconfig <= pconfig;

  apbo.pindex <= pindex;

  regs : process(clk) is

  begin

    if rising_edge(clk) then r <= rin; end if;

  end process;

-- boot message

-- pragma translate_off

    bootmsg : report_version

    generic map ("ahbstat" & tost(pindex) &

        ": AHB status unit rev " & tost(VERSION) &

        ", irq " & tost(pirq));

-- pragma translate_on

end architecture;