Subversion Repositories core_arm

-- $(lic)

-- $(help_generic)

-- $(help_local)

library IEEE;

use IEEE.std_logic_1164.all;

use IEEE.std_logic_unsigned."+";

use IEEE.std_logic_arith.conv_unsigned;

use work.amba.all;

use work.memdef.all;

use work.int.all;

use work.bus_comp.all;

entity ahbmst_mp is

  generic ( AHBMST_PORTS : integer := 4 );

  port (

    rst   : in  std_logic;

    clk   : in  std_logic;

    i     : in  ahbmst_mp_in_a(AHBMST_PORTS-1 downto 0);

    o     : out ahbmst_mp_out_a(AHBMST_PORTS-1 downto 0);

    ahbi  : in  ahb_mst_in_type;

    ahbo  : out ahb_mst_out_type

  );

end;

architecture rtl of ahbmst_mp is

  constant AHBMST_PORTS_BITSZ : integer := lin_log2x(AHBMST_PORTS);

  constant NBO_ZERO : std_logic_vector(AHBMST_PORTS-1 downto 0) := (others => '0');

  type ahbmst_mp_tmp_type is record

    ahbo   : ahb_mst_out_type;

    bo_i,nbo_i   : integer;

    o_ready, o_grant, o_mexc : std_logic_vector(AHBMST_PORTS-1 downto 0);

    o_retry, o_cache, hold, nboreq : std_logic_vector(AHBMST_PORTS-1 downto 0);

    nbo : std_logic_vector(AHBMST_PORTS_BITSZ-1 downto 0);

    num : std_logic_vector(AHBMST_PORTS_BITSZ-1 downto 0);

  end record;

  type ahbmst_mp_reg_type is record

     retry, cache : std_logic;

     bo    : std_logic_vector(AHBMST_PORTS_BITSZ-1 downto 0);

     ba, bg : std_logic;

  end record;

  type ahbmst_mp_dbg_type is record

     dummy : std_logic;

     -- pragma translate_off

     dbg : ahbmst_mp_tmp_type;

     -- pragma translate_on

  end record;

  signal r, c       : ahbmst_mp_reg_type;

  signal rdbg, cdbg : ahbmst_mp_dbg_type;

begin

  p0 : process(ahbi, r, rst, i)

    variable v    : ahbmst_mp_reg_type;

    variable t    : ahbmst_mp_tmp_type;

    variable vdbg : ahbmst_mp_dbg_type;

  begin

    -- $(init(t:ahbmst_mp_tmp_type))

    v := r;

    t.o_ready := (others => '0');

    t.o_grant := (others => '0');

    t.o_retry := (others => '0');

    t.o_cache := (others => '0');

    t.o_mexc := (others => '0');

    -- owner hold 

    t.num := (others => '0');

    t.hold := (others => '0');

    for j in AHBMST_PORTS-1 downto 0 loop

      t.num := std_logic_vector(conv_unsigned(j, AHBMST_PORTS_BITSZ));

      if (r.ba = '1') and

         (i(j).req = '1') and

         (r.bo = t.num) then

        t.hold(j) := '1';

      end if;

    end loop;  -- i

    -- next bus owner req

    for k in AHBMST_PORTS-1 downto 0 loop

      t.nboreq(k) := i(k).req;

      for j in AHBMST_PORTS-1 downto 0 loop

        if k /= j then

          if t.hold(j) = '1' then

            t.nboreq(k) := '0';

          end if;

        end if;

      end loop;

    end loop;

    -- priority 

    t.nbo_i := 0;

l1: for j in AHBMST_PORTS-1 downto 0 loop

      if t.nboreq(j) = '1' then

        t.nbo_i := j;

        exit l1;

      end if;

    end loop;

    -- lock (only per ahb)

    t.ahbo.hlock := '0';

    for j in AHBMST_PORTS-1 downto 0 loop

      if i(j).lock = '1' then

        t.ahbo.hlock := '1';

      end if;

    end loop;

    -- ahb signals

    t.ahbo.hbusreq := '0';

    t.ahbo.htrans  := HTRANS_IDLE;

    t.ahbo.haddr   := i(0).address;

    if not (t.nboreq = NBO_ZERO) then

      t.nbo := std_logic_vector(conv_unsigned(t.nbo_i, AHBMST_PORTS_BITSZ));

      t.ahbo.hbusreq := i(t.nbo_i).req;

      t.ahbo.haddr   := i(t.nbo_i).address;

      t.ahbo.htrans  := HTRANS_NONSEQ;

      t.ahbo.hwrite  := not i(t.nbo_i).read;

      t.ahbo.hsize   := lmd_toamba(i(t.nbo_i).size);

      t.ahbo.hburst := HBURST_SINGLE;

      if i(t.nbo_i).burst = '1' then

        t.ahbo.hburst := HBURST_INCR;

      end if;

      -- burst

      if (r.bo = t.nbo) then

        if (i(t.nbo_i).req = '1') and (r.ba = '1')  then

          if ((not r.retry) = '1') then

            if i(t.nbo_i).burst = '1' then

              t.ahbo.htrans := HTRANS_SEQ;

              -- todo: 1k boundary check

              t.ahbo.hburst := HBURST_INCR;

            end if;

          end if;

        end if;

      end if;

      -- grant

      if (r.bg = '1') then

        if (ahbi.hready = '1') and (i(t.nbo_i).req = '1') then

          if ((not r.retry) = '1') then

            t.o_grant(t.nbo_i) := '1';

          end if;

        end if;

      end if;

    end if;

    -- retry

    v.retry := '0';

    if (r.ba = '1') and

       ((ahbi.hresp = HRESP_RETRY) or

        (ahbi.hresp = HRESP_SPLIT))

    then

      v.retry := not ahbi.hready;

    end if;

    if r.retry = '1' then

      t.ahbo.htrans := HTRANS_IDLE;

    end if;

    -- ahb return

    t.bo_i := lin_convint(r.bo);

    t.ahbo.hwdata := i(t.bo_i).data;

    if r.ba = '1' then

      t.o_cache(t.bo_i) := r.cache;

      if ahbi.hready = '1' then

        case ahbi.hresp is

          when HRESP_OKAY => t.o_ready(t.bo_i) := '1';

          when HRESP_RETRY | HRESP_SPLIT=> t.o_retry(t.bo_i) := '1';

          when others => t.o_ready(t.bo_i) := '1'; t.o_mexc(t.bo_i) := '1';

        end case;

      end if;

    end if;

    -- next

    if ahbi.hready = '1' then

      v.bo := t.nbo;

      v.bg := ahbi.hgrant;

      v.ba := '0';

      if (t.ahbo.htrans = HTRANS_NONSEQ) or (t.ahbo.htrans = HTRANS_SEQ) then

        v.ba := r.bg;

      end if;

    end if;

    -- reset

    if rst = '0' then

      v.retry := '0';

      v.cache := '0';

      v.bo := (others => '0');

      v.ba := '0';

      v.bg := '0';

    end if;

    c <= v;

    for i in AHBMST_PORTS-1 downto 0 loop

      o(i).grant <= t.o_grant(i);

      o(i).ready <= t.o_ready(i);

      o(i).mexc <=  t.o_mexc(i);

      o(i).retry <= t.o_retry(i);

      o(i).data  <= ahbi.hrdata;

    end loop;

    ahbo   <= t.ahbo;

    -- pragma translate_off

    vdbg := rdbg;

    vdbg.dbg := t;

    cdbg <= vdbg;

    -- pragma translate_on  end process p0;

  end process p0;

  pregs : process (clk, c)

  begin

    if rising_edge(clk) then

      r <= c;

      -- pragma translate_off

      rdbg <= cdbg;

      -- pragma translate_on

    end if;

  end process;

end;