Subversion Repositories spi_slave

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

--* 

--* @short OPB-Master Interface

--* 

--* Generics described in top entity.

--*

--* @see opb_spi_slave

--*    @author: Daniel Köthe

--*   @version: 1.0

--* @date: 2007-11-11

--/

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

library ieee;

use ieee.std_logic_1164.all;

use IEEE.STD_LOGIC_ARITH.all;

use IEEE.STD_LOGIC_UNSIGNED.all;

use IEEE.numeric_std.all;               -- conv_integer()

library work;

use work.opb_spi_slave_pack.all;

entity opb_m_if is

  generic (

    C_BASEADDR        : std_logic_vector(0 to 31) := X"00000000";

    C_HIGHADDR        : std_logic_vector(0 to 31) := X"FFFFFFFF";

    C_USER_ID_CODE    : integer                   := 0;

    C_OPB_AWIDTH      : integer                   := 32;

    C_OPB_DWIDTH      : integer                   := 32;

    C_FAMILY          : string                    := "virtex-4";

    C_SR_WIDTH        : integer                   := 8;

    C_MSB_FIRST       : boolean                   := true;

    C_CPOL            : integer range 0 to 1      := 0;

    C_PHA             : integer range 0 to 1      := 0;

    C_FIFO_SIZE_WIDTH : integer range 4 to 7      := 7);

  port (

    -- opb master interface

    OPB_Clk         : in  std_logic;

    OPB_Rst         : in  std_logic;

    OPB_DBus        : in  std_logic_vector(0 to C_OPB_DWIDTH-1);

    M_request       : out std_logic;

    MOPB_MGrant     : in  std_logic;

    M_busLock       : out std_logic;

    M_ABus          : out std_logic_vector(0 to C_OPB_AWIDTH-1);

    M_BE            : out std_logic_vector(0 to C_OPB_DWIDTH/8-1);

    M_DBus          : out std_logic_vector(0 to C_OPB_DWIDTH-1);

    M_RNW           : out std_logic;

    M_select        : out std_logic;

    M_seqAddr       : out std_logic;

    MOPB_errAck     : in  std_logic;

    MOPB_retry      : in  std_logic;

    MOPB_timeout    : in  std_logic;

    MOPB_xferAck    : in  std_logic;

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

    -- read transfer

    -- read data from memory and fill fifo

    opb_m_tx_req    : in  std_logic;

    opb_m_tx_en     : out std_logic;

    opb_m_tx_data   : out std_logic_vector(C_SR_WIDTH-1 downto 0);

    -- enable/disable dma transfer

    opb_tx_dma_ctl  : in  std_logic_vector(0 downto 0);

    -- base adress for transfer

    opb_tx_dma_addr : in  std_logic_vector(C_OPB_DWIDTH-1 downto 0);

    opb_tx_dma_num  : in  std_logic_vector(C_WIDTH_DMA_NUM-1 downto 0);

    opb_tx_dma_done : out std_logic;

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

    -- write transfer

    -- read fifo an write to memory 

    opb_m_rx_req    : in  std_logic;

    opb_m_rx_en     : out std_logic;

    opb_m_rx_data   : in  std_logic_vector(C_SR_WIDTH-1 downto 0);

    -- enable/disable dma transfer

    opb_rx_dma_ctl  : in  std_logic_vector(0 downto 0);

    -- base adress for transfer

    opb_rx_dma_addr : in  std_logic_vector(C_OPB_DWIDTH-1 downto 0);

    opb_rx_dma_num  : in  std_logic_vector(C_WIDTH_DMA_NUM-1 downto 0);

    opb_rx_dma_done : out std_logic);

end opb_m_if;

architecture behavior of opb_m_if is

  type state_t is (idle,

                   wait_grant,

                   transfer_write,

                   transfer_read,

                   done);

  signal state : state_t := idle;

  signal M_DBus_big_end   : std_logic_vector(C_OPB_DWIDTH-1 downto 0);

  signal M_ABus_big_end   : std_logic_vector(C_OPB_DWIDTH-1 downto 0);

  signal OPB_DBus_big_end : std_logic_vector(C_OPB_DWIDTH-1 downto 0);

  signal M_select_int  : std_logic;

  signal read_transfer : boolean;

  -- read transfer

  signal opb_tx_dma_addr_int : std_logic_vector(C_OPB_DWIDTH-1 downto 0);

  signal opb_tx_dma_en       : std_logic;

  signal opb_tx_dma_num_int  : std_logic_vector(C_WIDTH_DMA_NUM-1 downto 0);

  signal opb_tx_dma_done_int : std_logic;

  -- write transfer

  signal opb_rx_dma_en       : std_logic;

  signal opb_rx_dma_addr_int : std_logic_vector(C_OPB_DWIDTH-1 downto 0);

  signal opb_rx_dma_num_int  : std_logic_vector(C_WIDTH_DMA_NUM-1 downto 0);

  signal opb_rx_dma_done_int : std_logic;

begin  -- behavior

  --* convert M_DBus_big_end to little endian

  process(M_DBus_big_end)

  begin

    for i in 0 to 31 loop

      M_DBus(31-i) <= M_DBus_big_end(i);

    end loop;  -- i  

  end process;

  --* convert M_ABus_big_end to little endian

  process(M_ABus_big_end)

  begin

    for i in 0 to 31 loop

      M_ABus(31-i) <= M_ABus_big_end(i);

    end loop;  -- i  

  end process;

  --* convert OPB_DBus to bi endian

  process(OPB_DBus)

  begin

    for i in 0 to 31 loop

      OPB_DBus_big_end(31-i) <= OPB_DBus(i);

    end loop;  -- i  

  end process;

  -- for both sides

  M_ABus_big_end <= opb_tx_dma_addr_int when (M_select_int = '1' and (read_transfer = true)) else

                    opb_rx_dma_addr_int when (M_select_int = '1' and (read_transfer = false)) else

                    (others => '0');

  M_select <= M_select_int;

  -- write transfer

  opb_m_rx_en <= MOPB_xferAck when (M_select_int = '1' and (read_transfer = false)) else

                 '0';

  M_DBus_big_end(C_SR_WIDTH-1 downto 0) <= opb_m_rx_data when (M_select_int = '1' and (read_transfer = false)) else

                                           (others => '0');

  M_DBus_big_end(C_OPB_DWIDTH-1 downto C_SR_WIDTH) <= (others => '0');

  opb_tx_dma_done <= opb_tx_dma_done_int;

  -- read transfer

  opb_m_tx_en <= MOPB_xferAck when (M_select_int = '1' and (read_transfer = true)) else

                 '0';

  opb_m_tx_data <= OPB_DBus_big_end(C_SR_WIDTH-1 downto 0);

  opb_rx_dma_done <= opb_rx_dma_done_int;

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

  opb_masteer_proc: process(OPB_Rst, OPB_Clk)

  begin

    if (OPB_Rst = '1') then

      M_BE            <= (others => '0');

      M_busLock       <= '0';

      M_request       <= '0';

      M_RNW           <= '0';

      M_select_int    <= '0';

      M_seqAddr       <= '0';

      opb_tx_dma_done_int <= '0';

      opb_rx_dma_done_int <= '0';

    elsif rising_edge(OPB_Clk) then

      case state is

        when idle =>

          opb_tx_dma_en <= opb_tx_dma_ctl(0);

          opb_rx_dma_en <= opb_rx_dma_ctl(0);

          if (opb_tx_dma_ctl(0) = '1' and opb_tx_dma_en = '0') then

            opb_tx_dma_addr_int <= opb_tx_dma_addr;

            opb_tx_dma_num_int  <= opb_tx_dma_num;

            opb_tx_dma_done_int     <= '0';

          end if;

          if (opb_rx_dma_ctl(0) = '1' and opb_rx_dma_en = '0') then

            opb_rx_dma_addr_int <= opb_rx_dma_addr;

            opb_rx_dma_num_int  <= opb_rx_dma_num;

            opb_rx_dma_done_int    <= '0';

          end if;

          if (opb_tx_dma_en = '1' and opb_m_tx_req = '1' and opb_tx_dma_done_int = '0') then

            -- read from memory to fifo

            M_request     <= '1';

            read_transfer <= true;

            state         <= wait_grant;

          elsif (opb_rx_dma_en = '1' and opb_m_rx_req = '1'and opb_rx_dma_done_int = '0') then

            -- read from fifo and write memory

            M_request     <= '1';

            read_transfer <= false;

            state         <= wait_grant;

          else

            state <= idle;

          end if;

        when wait_grant =>

          if (MOPB_MGrant = '1') then

            M_request    <= '0';

            M_busLock    <= '1';

            M_select_int <= '1';

            M_seqAddr    <= '1';

            M_BE         <= "1111";

            if (read_transfer) then

              -- read

              M_RNW <= '1';

              state <= transfer_read;

            else

              -- write

              M_RNW <= '0';

              state <= transfer_write;

            end if;

          else

            state <= wait_grant;

          end if;

        when transfer_read =>

          if (MOPB_xferAck = '1') then

            opb_tx_dma_addr_int <= opb_tx_dma_addr_int +4;

            if (opb_tx_dma_addr_int(5 downto 2) = conv_std_logic_vector(14, 4)) then

              -- cycle 14

              -- deassert buslock and seq_address 1 cycle before transfer complete

              M_busLock <= '0';

              M_seqAddr <= '0';

            elsif (opb_tx_dma_addr_int(5 downto 2) = conv_std_logic_vector(15, 4)) then

              -- cycle 15

              M_RNW        <= '0';

              M_select_int <= '0';

              M_BE         <= (others => '0');

              if (conv_integer(opb_tx_dma_num_int) = 0) then

                opb_tx_dma_done_int <= '1';

              else

                opb_tx_dma_num_int <= opb_tx_dma_num_int-1;

              end if;

              state <= done;

            end if;

          elsif (MOPB_retry = '1' or MOPB_errAck = '1' or MOPB_timeout = '1') then

            -- cancel transfer

            M_busLock    <= '0';

            M_seqAddr    <= '0';

            M_RNW        <= '0';

            M_select_int <= '0';

            M_BE         <= (others => '0');

            state        <= done;

          else

            state <= transfer_read;

          end if;

        when transfer_write =>

          if (MOPB_xferAck = '1') then

            opb_rx_dma_addr_int <= opb_rx_dma_addr_int +4;

            if (opb_rx_dma_addr_int(5 downto 2) = conv_std_logic_vector(14, 4)) then

              -- cycle 14

              -- deassert buslock and seq_address 1 cycle before transfer complete

              M_busLock <= '0';

              M_seqAddr <= '0';

            elsif (opb_rx_dma_addr_int(5 downto 2) = conv_std_logic_vector(15, 4)) then

              -- cycle 15

              M_RNW        <= '0';

              M_select_int <= '0';

              M_BE         <= (others => '0');

              if (conv_integer(opb_rx_dma_num_int) = 0) then

                opb_rx_dma_done_int <= '1';

              else

                opb_rx_dma_num_int <= opb_rx_dma_num_int-1;

              end if;

              state <= done;

            end if;

          elsif (MOPB_retry = '1' or MOPB_errAck = '1' or MOPB_timeout = '1') then

            -- cancel transfer

            M_busLock    <= '0';

            M_seqAddr    <= '0';

            M_RNW        <= '0';

            M_select_int <= '0';

            M_BE         <= (others => '0');

            state        <= done;

          else

            state <= transfer_write;

          end if;

        when done =>

          state <= idle;

        when others =>

          state <= idle;

      end case;

    end if;

  end process opb_masteer_proc;

end behavior;