antonblanchard.microwatt/fpga/top-generic.vhdl

library ieee;
use ieee.std_logic_1164.all;

library work;
use work.wishbone_types.all;

entity toplevel is
    generic (
	MEMORY_SIZE   : positive := (384*1024);
	RAM_INIT_FILE : string   := "firmware.hex";
	RESET_LOW     : boolean  := true;
	CLK_INPUT     : positive := 100000000;
	CLK_FREQUENCY : positive := 100000000;
	DISABLE_FLATTEN_CORE : boolean := false
	);
    port(
	ext_clk   : in  std_ulogic;
	ext_rst   : in  std_ulogic;

	-- UART0 signals:
	uart0_txd : out std_ulogic;
	uart0_rxd : in  std_ulogic
	);
end entity toplevel;

architecture behaviour of toplevel is

    -- Reset signals:
    signal soc_rst : std_ulogic;
    signal pll_rst : std_ulogic;

    -- Internal clock signals:
    signal system_clk : std_ulogic;
    signal system_clk_locked : std_ulogic;

    -- DRAM main data wishbone connection
    signal wb_dram_in       : wishbone_master_out;
    signal wb_dram_out      : wishbone_slave_out;

    -- DRAM control wishbone connection
    signal wb_dram_ctrl_in  : wb_io_master_out;
    signal wb_dram_ctrl_out : wb_io_slave_out;
    signal wb_dram_is_csr   : std_ulogic;
    signal wb_dram_is_init  : std_ulogic;

begin

    reset_controller: entity work.soc_reset
	generic map(
	    RESET_LOW => RESET_LOW
	    )
	port map(
	    ext_clk => ext_clk,
	    pll_clk => system_clk,
	    pll_locked_in => system_clk_locked,
	    ext_rst_in => ext_rst,
	    pll_rst_out => pll_rst,
	    rst_out => soc_rst
	    );

    clkgen: entity work.clock_generator
	generic map(
	    CLK_INPUT_HZ => CLK_INPUT,
	    CLK_OUTPUT_HZ => CLK_FREQUENCY
	    )
	port map(
	    ext_clk => ext_clk,
	    pll_rst_in => pll_rst,
	    pll_clk_out => system_clk,
	    pll_locked_out => system_clk_locked
	    );

    -- Main SoC
    soc0: entity work.soc
	generic map(
	    MEMORY_SIZE   => MEMORY_SIZE,
	    RAM_INIT_FILE => RAM_INIT_FILE,
	    RESET_LOW     => RESET_LOW,
	    SIM           => false,
	    CLK_FREQ      => CLK_FREQUENCY,
	    DISABLE_FLATTEN_CORE => DISABLE_FLATTEN_CORE,
            HAS_SPI          => false
	    )
	port map (
	    system_clk        => system_clk,
	    rst               => soc_rst,
	    uart0_txd         => uart0_txd,
	    uart0_rxd         => uart0_rxd,
            spi0_sck          => open,
            spi0_cs_n         => open,
            spi0_sdat_o       => open,
            spi0_sdat_oe      => open,
            spi0_sdat_i       => '1',
	    wb_dram_in        => wb_dram_in,
	    wb_dram_out       => wb_dram_out,
	    wb_dram_ctrl_in   => wb_dram_ctrl_in,
	    wb_dram_ctrl_out  => wb_dram_ctrl_out,
	    wb_dram_is_csr    => wb_dram_is_csr,
	    wb_dram_is_init   => wb_dram_is_init,
	    alt_reset         => '0'
	    );

    -- Dummy DRAM
    wb_dram_out.ack <= wb_dram_in.cyc and wb_dram_in.stb;
    wb_dram_out.dat <= x"FFFFFFFFFFFFFFFF";
    wb_dram_out.stall <= wb_dram_in.cyc and not wb_dram_out.ack;
    wb_dram_ctrl_out.ack <= wb_dram_in.cyc and wb_dram_in.stb;
    wb_dram_ctrl_out.dat <= x"FFFFFFFF";
    wb_dram_ctrl_out.stall <= wb_dram_in.cyc and not wb_dram_out.ack;

end architecture behaviour;