fpga: Hookup nexys-video to litedram
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>pull/170/head
Benjamin Herrenschmidt
5 years ago
parent
3ac815823c
commit
2cef3005cd
@ -0,0 +1,207 @@
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library ieee;
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use ieee.std_logic_1164.all;
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use ieee.numeric_std.all;
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library unisim;
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use unisim.vcomponents.all;
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library work;
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use work.wishbone_types.all;
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entity toplevel is
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generic (
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MEMORY_SIZE : positive := 16384;
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RAM_INIT_FILE : string := "firmware.hex";
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RESET_LOW : boolean := true;
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CLK_FREQUENCY : positive := 100000000;
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USE_LITEDRAM : boolean := false;
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DISABLE_FLATTEN_CORE : boolean := false
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);
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port(
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ext_clk : in std_ulogic;
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ext_rst : in std_ulogic;
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-- UART0 signals:
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uart_main_tx : out std_ulogic;
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uart_main_rx : in std_ulogic;
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-- LEDs
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led0 : out std_logic;
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led1 : out std_logic;
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-- DRAM wires
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ddram_a : out std_logic_vector(14 downto 0);
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ddram_ba : out std_logic_vector(2 downto 0);
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ddram_ras_n : out std_logic;
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ddram_cas_n : out std_logic;
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ddram_we_n : out std_logic;
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ddram_dm : out std_logic_vector(1 downto 0);
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ddram_dq : inout std_logic_vector(15 downto 0);
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ddram_dqs_p : inout std_logic_vector(1 downto 0);
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ddram_dqs_n : inout std_logic_vector(1 downto 0);
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ddram_clk_p : out std_logic;
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ddram_clk_n : out std_logic;
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ddram_cke : out std_logic;
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ddram_odt : out std_logic;
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ddram_reset_n : out std_logic
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);
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end entity toplevel;
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architecture behaviour of toplevel is
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-- Reset signals:
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signal soc_rst : std_ulogic;
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signal pll_rst : std_ulogic;
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-- Internal clock signals:
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signal system_clk : std_ulogic;
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signal system_clk_locked : std_ulogic;
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-- DRAM wishbone connection
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signal wb_dram_in : wishbone_master_out;
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signal wb_dram_out : wishbone_slave_out;
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signal wb_dram_csr : std_ulogic;
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signal wb_dram_init : std_ulogic;
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-- Control/status
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signal core_alt_reset : std_ulogic;
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begin
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-- Main SoC
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soc0: entity work.soc
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generic map(
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MEMORY_SIZE => MEMORY_SIZE,
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RAM_INIT_FILE => RAM_INIT_FILE,
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RESET_LOW => RESET_LOW,
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SIM => false,
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HAS_DRAM => USE_LITEDRAM,
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DISABLE_FLATTEN_CORE => DISABLE_FLATTEN_CORE
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)
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port map (
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system_clk => system_clk,
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rst => soc_rst,
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uart0_txd => uart_main_tx,
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uart0_rxd => uart_main_rx,
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wb_dram_in => wb_dram_in,
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wb_dram_out => wb_dram_out,
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wb_dram_csr => wb_dram_csr,
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wb_dram_init => wb_dram_init,
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alt_reset => core_alt_reset
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);
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nodram: if not USE_LITEDRAM generate
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signal ddram_clk_dummy : std_ulogic;
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begin
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reset_controller: entity work.soc_reset
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generic map(
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RESET_LOW => RESET_LOW
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)
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port map(
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ext_clk => ext_clk,
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pll_clk => system_clk,
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pll_locked_in => system_clk_locked,
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ext_rst_in => ext_rst,
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pll_rst_out => pll_rst,
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rst_out => soc_rst
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);
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clkgen: entity work.clock_generator
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generic map(
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CLK_INPUT_HZ => 100000000,
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CLK_OUTPUT_HZ => CLK_FREQUENCY
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)
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port map(
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ext_clk => ext_clk,
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pll_rst_in => pll_rst,
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pll_clk_out => system_clk,
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pll_locked_out => system_clk_locked
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);
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led0 <= '1';
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led1 <= not soc_rst;
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core_alt_reset <= '0';
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-- Vivado barfs on those differential signals if left
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-- unconnected. So instanciate a diff. buffer and feed
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-- it a constant '0'.
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dummy_dram_clk: OBUFDS
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port map (
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O => ddram_clk_p,
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OB => ddram_clk_n,
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I => ddram_clk_dummy
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);
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ddram_clk_dummy <= '0';
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end generate;
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has_dram: if USE_LITEDRAM generate
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signal dram_init_done : std_ulogic;
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signal dram_init_error : std_ulogic;
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signal soc_rst_0 : std_ulogic;
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signal soc_rst_1 : std_ulogic;
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begin
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-- Eventually dig out the frequency from the generator
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-- but for now, assert it's 100Mhz
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assert CLK_FREQUENCY = 100000000;
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reset_controller: entity work.soc_reset
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generic map(
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RESET_LOW => RESET_LOW
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)
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port map(
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ext_clk => ext_clk,
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pll_clk => system_clk,
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pll_locked_in => system_clk_locked,
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ext_rst_in => ext_rst,
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pll_rst_out => pll_rst,
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rst_out => soc_rst_0
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);
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dram: entity work.litedram_wrapper
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generic map(
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DRAM_ABITS => 25,
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DRAM_ALINES => 15
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)
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port map(
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clk_in => ext_clk,
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rst => pll_rst,
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system_clk => system_clk,
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system_reset => soc_rst_1,
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pll_locked => system_clk_locked,
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wb_in => wb_dram_in,
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wb_out => wb_dram_out,
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wb_is_csr => wb_dram_csr,
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wb_is_init => wb_dram_init,
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serial_tx => open,
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serial_rx => '0',
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init_done => dram_init_done,
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init_error => dram_init_error,
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ddram_a => ddram_a,
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ddram_ba => ddram_ba,
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ddram_ras_n => ddram_ras_n,
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ddram_cas_n => ddram_cas_n,
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ddram_we_n => ddram_we_n,
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ddram_cs_n => open,
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ddram_dm => ddram_dm,
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ddram_dq => ddram_dq,
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ddram_dqs_p => ddram_dqs_p,
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ddram_dqs_n => ddram_dqs_n,
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ddram_clk_p => ddram_clk_p,
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ddram_clk_n => ddram_clk_n,
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ddram_cke => ddram_cke,
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ddram_odt => ddram_odt,
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ddram_reset_n => ddram_reset_n
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);
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led0 <= dram_init_done and not dram_init_error;
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led1 <= dram_init_error; -- Make it blink ?
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soc_rst <= soc_rst_0 or soc_rst_1;
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end generate;
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end architecture behaviour;
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