trashernet-soc/fpga/hdl/design/servant_ram.vhd

107 lines
2.8 KiB
VHDL

-- -------------------------------------------------------------------------- --
-- TRASHERNET SoC - A Trashy Ethernet SoC for FPGAs --
-- -------------------------------------------------------------------------- --
-- TODO
-- -------------------------------------------------------------------------- --
-- Author : Markus Koch <markus@notsyncing.net>
-- Contributors : None
-- License : Mozilla Public License (MPL) Version 2
-- -------------------------------------------------------------------------- --
library ieee;
use ieee.std_logic_1164.all;
use ieee.numeric_std.all;
library generics;
use generics.wishbone_pkg.all;
entity servant_ram_vhdl is
generic(
memfile : string := "data/empty.hex";
read_only : boolean := false;
adr_width : integer := 16;
force_vlog : boolean := false
);
port(
clk : in std_logic; -- CPU and bus clock
clr : in std_logic; -- Synchronous reset
wb_o : out wishbone_slave_out; -- Wishbone bus (out)
wb_i : in wishbone_slave_in -- Wishbone bus (in)
);
end entity servant_ram_vhdl;
architecture rtl of servant_ram_vhdl is
component servant_ram
generic(
depth : integer;
aw : integer;
memfile : string
);
port(
i_wb_clk : in std_logic;
i_wb_rst : in std_logic;
i_wb_adr : in std_logic_vector;
i_wb_dat : in std_logic_vector;
i_wb_sel : in std_logic_vector;
i_wb_we : in std_logic;
i_wb_cyc : in std_logic;
o_wb_rdt : out std_logic_vector;
o_wb_ack : out std_logic
);
end component servant_ram;
begin
vlogforce : if force_vlog generate
servant_ram_inst : component servant_ram
generic map(
depth => 2 ** adr_width,
aw => adr_width,
memfile => memfile
)
port map(
i_wb_clk => clk,
i_wb_rst => clr,
i_wb_adr => wb_i.adr(adr_width - 1 downto 2),
i_wb_dat => wb_i.dat,
i_wb_sel => wb_i.sel,
i_wb_we => wb_i.we,
i_wb_cyc => wb_i.cyc and wb_i.stb,
o_wb_rdt => wb_o.dat,
o_wb_ack => wb_o.ack
);
wb_o.rty <= '0';
wb_o.err <= '0';
wb_o.stall <= '0';
rowarn : process(clk) is
begin
if rising_edge(clk) then
if wb_i.cyc and wb_i.stb then
if (unsigned(wb_i.adr) > 2 ** adr_width - 1) then
report "ERROR: Out of bounds for " & servant_ram_vhdl'path_name & " @0x" & to_hstring(wb_i.adr) severity error;
end if;
if (wb_i.we = '1' and read_only) then
report "ERROR: Write access to ROM @0x" & to_hstring(wb_i.adr) severity warning;
end if;
end if;
end if;
end process rowarn;
else generate
ram_vhdl_inst : entity work.ram_vhdl
generic map(
memfile => memfile,
read_only => read_only,
adr_width => adr_width
)
port map(
clk => clk,
clr => clr,
wb_o => wb_o,
wb_i => wb_i
);
end generate vlogforce;
end architecture rtl;