mctrl.vhd

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----------------------------------------------------------------------------
--  This file is a part of the LEON VHDL model
--  Copyright (C) 1999  European Space Agency (ESA)
--
--  This library 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 of the License, or (at your option) any later version.
--
--  See the file COPYING.LGPL for the full details of the license.


-----------------------------------------------------------------------------
-- Entity: 	mctrl
-- File:	mctrl.vhd
-- Author:	Jiri Gaisler - ESA/ESTEC
-- Description:	Mememory controller. Implements the following interfaces:
--		* AMBA AHB slave interface 
--		* AMBA APB slave interface for internal register
--		* 8- and 32-bits external SRAM/IO bus
--		
--		Contains the two memory configuartion registers, cache
--		control register, power-down function, write protection
--		registers, memory status register
--		LEON configuration register.
------------------------------------------------------------------------------

library IEEE;
use IEEE.std_logic_1164.all;
use IEEE.std_logic_unsigned."+";
use IEEE.std_logic_unsigned."-";
use IEEE.std_logic_unsigned.conv_integer;
use IEEE.std_logic_arith.conv_unsigned;
use work.target.all;
use work.config.all;
use work.iface.all;
use work.sparcv8.all;
use work.macro.all;
use work.ramlib.all;
use work.amba.all;

entity mctrl is
  port (
    rst    : in  rst_type;
    clk    : in  clk_type;
    memi   : in  memory_in_type;
    memo   : out memory_out_type;
    ahbsi  : in  ahb_slv_in_type;
    ahbso  : out ahb_slv_out_type;
    apbi   : in  apb_slv_in_type;
    apbo   : out apb_slv_out_type;
    pioo   : in  pio_out_type;
    wpo    : in  wprot_out_type;
    mctrlo : out mctrl_out_type
  );
end; 

architecture rtl of mctrl is


type areatype is (rom, io, ram);
type memcycletype is (idle, berr, bread, bwrite, bread8, bwrite8, bread16, bwrite16);


-- memory configuration register 1 type

type mcfg1type is record
  romrws           : std_logic_vector(3 downto 0);
  romwws           : std_logic_vector(3 downto 0);
  romwidth         : std_logic_vector(1 downto 0);
  romwrite         : std_logic;

  extlatch         : std_logic;
  ioen             : std_logic;
  iows             : std_logic_vector(3 downto 0);
  bexcen           : std_logic;
  brdyen           : std_logic;
  iowidth          : std_logic_vector(1 downto 0);
end record;

-- memory configuration register 2 type

type mcfg2type is record
  ramrws           : std_logic_vector(1 downto 0);
  ramwws           : std_logic_vector(1 downto 0);
  ramwidth         : std_logic_vector(1 downto 0);
  rambanksz        : std_logic_vector(3 downto 0);
  rmw              : std_logic;
end record;

-- memory status register type



-- register used only for 8-bit bus access
type bus8reg is record
  ready            : std_logic;

end record;

-- local registers

type reg_type is record
  address          : std_logic_vector(31 downto 0);  -- memory address
  data             : std_logic_vector(31 downto 0);  -- latched memory data
  ba               : std_logic_vector(1 downto 0);   
  writedata        : std_logic_vector(31 downto 0);
  readdata         : std_logic_vector(31 downto 0);
  brdyn            : std_logic;
  ready            : std_logic;
  wren             : std_logic;
  bdrive           : std_logic_vector(3 downto 0);
  ws               : std_logic_vector(3 downto 0);
  romsn		   : std_logic_vector(1 downto 0);
  ramsn		   : std_logic_vector(3 downto 0);
  ramoen	   : std_logic_vector(3 downto 0);
  size		   : std_logic_vector(1 downto 0);
  busw		   : std_logic_vector(1 downto 0);
  oen              : std_logic;
  iosn             : std_logic;
  read             : std_logic;
  wrn              : std_logic_vector(3 downto 0);
  writen           : std_logic;
  bstate           : memcycletype;
  area  	   : areatype;
  mcfg1		   : mcfg1type;
  mcfg2		   : mcfg2type;
  bexcn            : std_logic;		-- latched external bexcn
  echeck           : std_logic;
  pwd              : std_logic;
  rmw              : std_logic;
  brmw             : std_logic;

  hsel             : std_logic;
  hwrite           : std_logic;
  haddr            : std_logic_vector(31 downto 0);
  hburst           : std_logic_vector(2 downto 0);
  htrans           : std_logic_vector(1 downto 0);
  hresp 	   : std_logic_vector(1 downto 0);
end record;


signal r, ri : reg_type;
signal b8reg, b8regin : bus8reg;
signal wrnout : std_logic_vector(3 downto 0);
signal promdata : std_logic_vector(31 downto 0); -- data from boot-prom

begin

  ctrl : process(rst, ahbsi, apbi, memi, r, pioo, b8reg, promdata, wpo

		)
  variable v : reg_type;		-- local variables for registers
  variable cbout : std_logic_vector(6 downto 0);	-- EDAC checkbits
  variable start : std_logic;
  variable dataout : std_logic_vector(31 downto 0); -- data from memory
  variable regsd : std_logic_vector(31 downto 0);   -- data from registers
  variable memdata : std_logic_vector(31 downto 0);   -- data to memory
  variable rws : std_logic_vector(3 downto 0);		-- read waitstates
  variable wws : std_logic_vector(3 downto 0);		-- write waitstates
  variable wsnew : std_logic_vector(3 downto 0);		-- write waitstates
  variable adec : std_logic_vector(1 downto 0);
  variable rams : std_logic_vector(3 downto 0);
  variable bready, leadin : std_logic;
  variable csen : std_logic;			-- Generate chip selects
  variable aprot   : std_logic_vector(14 downto 0); -- 
  variable wrn   : std_logic_vector(3 downto 0); -- 
  variable bexc, addrerr : std_logic;
  variable ready : std_logic;
  variable b8v : bus8reg;
  variable writedata : std_logic_vector(31 downto 0);
  variable merrtype  : std_logic_vector(2 downto 0); -- memory error type
  variable noerror : std_logic;
  variable area  : areatype;
  variable bdrive, ramsn : std_logic_vector(3 downto 0);
  variable romsn, busw : std_logic_vector(1 downto 0);
  variable iosn : std_logic;
  variable lock : std_logic;
  variable wprothitx : std_logic;
  variable brmw : std_logic;

  begin

-- Variable default settings to avoid latches

    v := r; b8v := b8reg; wprothitx := '0';

    ready := '0'; addrerr := '0'; regsd := (others => '0'); csen := '0';

    v.ready := '0'; v.wren := '0';  v.echeck := '0'; 
    b8v.ready := '0'; v.rmw := '0'; merrtype := "---"; bready := '1';

    v.data := memi.data; v.bexcn := memi.bexcn; v.brdyn := memi.brdyn;
    bready := (not r.brdyn) or not r.mcfg1.brdyen;

    v.hresp := HRESP_OKAY;



-- decode memory area parameters

    case ahbsi.haddr(30 downto 28) is
    when "000" | "001" => area := rom;
    when "010" | "011" => area := io;
    when others => area := ram;
    end case;

    leadin := '0'; rws := "----"; wws := "----"; adec := "--";
    busw := (others => '-'); brmw := '0';
    case area is
    when rom => 

      busw := r.mcfg1.romwidth;
      brmw := '0';
    when ram => 
      adec := genmux(r.mcfg2.rambanksz, ahbsi.haddr(29 downto 14)) &
              genmux(r.mcfg2.rambanksz, ahbsi.haddr(28 downto 13));
      busw := r.mcfg2.ramwidth;
      if ((r.mcfg2.rmw and ahbsi.hwrite) = '1') and 
	  ((BUS16EN and (busw = "01") and (ahbsi.hsize(1 downto 0) = "00")) or
	   ((busw(1) = '1') and (ahbsi.hsize(1) = '0'))) 
      then
	brmw := '1';
      end if;
    when io =>
      leadin := '1'; wws := r.mcfg1.iows;
      busw := r.mcfg1.iowidth;
      brmw := '0';
    when others =>
    end case;

-- decode waitstates external

    case r.area is
    when rom =>
      rws := r.mcfg1.romrws; wws := r.mcfg1.romrws;
      if (r.mcfg1.romwrite or r.read) = '0' then addrerr := '1'; end if;
    when ram =>
      rws := "00" & r.mcfg2.ramrws; wws := "00" & r.mcfg2.ramrws;
    when io => rws := r.mcfg1.iows; 
      rws := r.mcfg1.iows; wws := r.mcfg1.iows;
      if r.mcfg1.ioen = '0' then addrerr := '1'; end if;
    when others => null;
    end case;

-- generate write strobes

    bdrive := (others => '1');
    case r.busw is
    when "00" => if BUS8EN then bdrive := "0001"; end if;
    when "01" => if BUS16EN then bdrive := "0011"; end if;
    when others =>
    end case;

-- generate chip select and output enable

    rams := decode(adec);

    iosn := '1'; ramsn := (others => '1'); romsn := (others => '1');
    case area is
    when rom => romsn(0) := ahbsi.haddr(28); romsn(1) := not ahbsi.haddr(28);
    when ram => ramsn := not rams;
    when io => iosn := '0'; 
    when others => null;
    end case;

-- generate write strobe

    wrn := "0000";
    case r.busw is
    when "00" => 
      if BUS8EN then wrn := "1110"; end if;
    when "01" => 
      if BUS16EN then
	if (r.size = "00") and (r.brmw = '0') then
	  wrn := "11" & (not r.address(0)) & r.address(0);
        else wrn := "1100"; end if;
      end if;
    when "10" | "11" =>
      case r.size is
      when "00" => 
        case r.address(1 downto 0) is
        when "00" => wrn := "1110";
        when "01" => wrn := "1101";
        when "10" => wrn := "1011";
        when others => wrn := "0111";
        end case;
      when "01" => 
        wrn := not r.address(1) & not r.address(1) & r.address(1) & r.address(1);
      when others => null;
      end case;
    when others => null;
    end case;

    if (r.mcfg2.rmw = '1') and (r.area = ram) then wrn := not bdrive; end if;

    if ((ahbsi.hready and ahbsi.hsel) = '1') then
      v.size := ahbsi.hsize(1 downto 0); v.area := area;
      v.hburst := ahbsi.hburst; v.htrans := ahbsi.htrans;
      v.address  := ahbsi.haddr;
      if (busw = "00") and (ahbsi.hwrite = '0') and BUS8EN
      then v.address(1 downto 0) := "00"; end if;
      if (busw = "01") and (ahbsi.hwrite = '0') and BUS16EN
      then v.address(1 downto 0) := "00"; end if;
      if (brmw = '1') then v.read := '1';
      else v.read := not ahbsi.hwrite; end if;
      v.hwrite := ahbsi.hwrite;
      v.busw := busw;
      v.brmw := brmw;
    end if;

-- Merge (corrected) data during byte write


    if BUS8EN and (r.busw = "00") then 

      memdata := r.readdata(23 downto 0) & r.data(31 downto 24);
    elsif BUS16EN and (r.busw = "01") then 
      memdata := r.readdata(15 downto 0) & r.data(31 downto 16);
    else memdata := r.data; end if;

    writedata := ahbsi.hwdata;
    if (r.brmw and r.busw(1)) = '1' then
      case r.address(1 downto 0) is
      when "00" => 
	writedata(15 downto 0) := memdata(15 downto 0);
	if r.size = "00" then 
	  writedata(23 downto 16) := memdata(23 downto 16);
	end if;
      when "01" => 
	writedata(31 downto 24) := memdata(31 downto 24);
	writedata(15 downto 0) := memdata(15 downto 0);
      when "10" => 
	writedata(31 downto 16) := memdata(31 downto 16);
	if r.size = "00" then 
	  writedata(7 downto 0) := memdata(7 downto 0);
	end if;
      when  others => 
	writedata(31 downto 8) := memdata(31 downto 8);
      end case;
    end if;
    if ((r.brmw and not r.busw(1)) = '1') and BUS16EN then
      if (r.address(0) = '0') then 
        writedata(23 downto 16) :=  r.data(23 downto 16);