You cannot select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
microwatt/litedram/generated/nexys-video/litedram-initmem.vhdl

73 lines
1.9 KiB
VHDL

library ieee;
use ieee.std_logic_1164.all;
use ieee.numeric_std.all;
use std.textio.all;
library work;
use work.wishbone_types.all;
entity dram_init_mem is
port (
clk : in std_ulogic;
wb_in : in wb_io_master_out;
wb_out : out wb_io_slave_out
);
end entity dram_init_mem;
architecture rtl of dram_init_mem is
constant INIT_RAM_SIZE : integer := 16384;
constant INIT_RAM_ABITS :integer := 14;
constant INIT_RAM_FILE : string := "litedram_core.init";
type ram_t is array(0 to (INIT_RAM_SIZE / 4) - 1) of std_logic_vector(31 downto 0);
impure function init_load_ram(name : string) return ram_t is
file ram_file : text open read_mode is name;
variable temp_word : std_logic_vector(63 downto 0);
variable temp_ram : ram_t := (others => (others => '0'));
variable ram_line : line;
begin
for i in 0 to (INIT_RAM_SIZE/8)-1 loop
exit when endfile(ram_file);
readline(ram_file, ram_line);
hread(ram_line, temp_word);
temp_ram(i*2) := temp_word(31 downto 0);
temp_ram(i*2+1) := temp_word(63 downto 32);
end loop;
return temp_ram;
end function;
signal init_ram : ram_t := init_load_ram(INIT_RAM_FILE);
attribute ram_style : string;
attribute ram_style of init_ram: signal is "block";
begin
init_ram_0: process(clk)
variable adr : integer;
begin
if rising_edge(clk) then
wb_out.ack <= '0';
if (wb_in.cyc and wb_in.stb) = '1' then
adr := to_integer((unsigned(wb_in.adr(INIT_RAM_ABITS-1 downto 2))));
if wb_in.we = '0' then
wb_out.dat <= init_ram(adr);
else
for i in 0 to 3 loop
if wb_in.sel(i) = '1' then
init_ram(adr)(((i + 1) * 8) - 1 downto i * 8) <=
wb_in.dat(((i + 1) * 8) - 1 downto i * 8);
end if;
end loop;
end if;
wb_out.ack <= '1';
end if;
end if;
end process;
wb_out.stall <= '0';
end architecture rtl;