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microwatt/soc.vhdl

178 lines
4.6 KiB
VHDL

library ieee;
use ieee.std_logic_1164.all;
use ieee.math_real.all;
use std.textio.all;
library work;
use work.common.all;
use work.wishbone_types.all;
-- 0x00000000: Main memory (1 MB)
-- 0xc0002000: UART0 (for host communication)
entity soc is
generic (
MEMORY_SIZE : positive;
RAM_INIT_FILE : string;
RESET_LOW : boolean;
SIM : boolean
);
port(
rst : in std_ulogic;
system_clk : in std_ulogic;
-- UART0 signals:
uart0_txd : out std_ulogic;
uart0_rxd : in std_ulogic
);
end entity soc;
architecture behaviour of soc is
-- Wishbone master signals:
signal wishbone_dcore_in : wishbone_slave_out;
signal wishbone_dcore_out : wishbone_master_out;
signal wishbone_icore_in : wishbone_slave_out;
signal wishbone_icore_out : wishbone_master_out;
-- Wishbone master (output of arbiter):
signal wb_master_in : wishbone_slave_out;
signal wb_master_out : wishbone_master_out;
-- UART0 signals:
signal wb_uart0_in : wishbone_master_out;
signal wb_uart0_out : wishbone_slave_out;
signal uart_dat8 : std_ulogic_vector(7 downto 0);
-- Main memory signals:
signal wb_bram_in : wishbone_master_out;
signal wb_bram_out : wishbone_slave_out;
constant mem_adr_bits : positive := positive(ceil(log2(real(MEMORY_SIZE))));
-- Debug signals (used in SIM only)
signal registers : regfile;
signal terminate : std_ulogic;
begin
-- Processor core
processor: entity work.core
generic map(
SIM => SIM
)
port map(
clk => system_clk,
rst => rst,
wishbone_insn_in => wishbone_icore_in,
wishbone_insn_out => wishbone_icore_out,
wishbone_data_in => wishbone_dcore_in,
wishbone_data_out => wishbone_dcore_out,
registers => registers,
terminate_out => terminate
);
-- Wishbone bus master arbiter & mux
wishbone_arbiter_0: entity work.wishbone_arbiter
port map(
clk => system_clk,
rst => rst,
wb1_in => wishbone_dcore_out,
wb1_out => wishbone_dcore_in,
wb2_in => wishbone_icore_out,
wb2_out => wishbone_icore_in,
wb_out => wb_master_out,
wb_in => wb_master_in
);
-- Wishbone slaves address decoder & mux
slave_intercon: process(wb_master_out, wb_bram_out, wb_uart0_out)
-- Selected slave
type slave_type is (SLAVE_UART,
SLAVE_MEMORY,
SLAVE_NONE);
variable slave : slave_type;
begin
-- Simple address decoder
slave := SLAVE_NONE;
if wb_master_out.adr(63 downto 24) = x"0000000000" then
slave := SLAVE_MEMORY;
elsif wb_master_out.adr(63 downto 24) = x"00000000c0" then
if wb_master_out.adr(15 downto 12) = x"2" then
slave := SLAVE_UART;
end if;
end if;
-- Wishbone muxing. Defaults:
wb_bram_in <= wb_master_out;
wb_bram_in.cyc <= '0';
wb_uart0_in <= wb_master_out;
wb_uart0_in.cyc <= '0';
case slave is
when SLAVE_MEMORY =>
wb_bram_in.cyc <= wb_master_out.cyc;
wb_master_in <= wb_bram_out;
when SLAVE_UART =>
wb_uart0_in.cyc <= wb_master_out.cyc;
wb_master_in <= wb_uart0_out;
when others =>
wb_master_in.dat <= (others => '1');
wb_master_in.ack <= wb_master_out.stb and wb_master_out.cyc;
end case;
end process slave_intercon;
-- Simulated memory and UART
sim_terminate_test: if SIM generate
-- Dump registers if core terminates
dump_registers: process(all)
begin
if terminate = '1' then
loop_0: for i in 0 to 31 loop
report "REG " & to_hstring(registers(i));
end loop loop_0;
assert false report "end of test" severity failure;
end if;
end process;
end generate;
-- UART0 wishbone slave
-- XXX FIXME: Need a proper wb64->wb8 adapter that
-- converts SELs into low address bits and muxes
-- data accordingly (either that or rejects large
-- cycles).
uart0: entity work.pp_soc_uart
generic map(
FIFO_DEPTH => 32
)
port map(
clk => system_clk,
reset => rst,
txd => uart0_txd,
rxd => uart0_rxd,
wb_adr_in => wb_uart0_in.adr(11 downto 0),
wb_dat_in => wb_uart0_in.dat(7 downto 0),
wb_dat_out => uart_dat8,
wb_cyc_in => wb_uart0_in.cyc,
wb_stb_in => wb_uart0_in.stb,
wb_we_in => wb_uart0_in.we,
wb_ack_out => wb_uart0_out.ack
);
wb_uart0_out.dat <= x"00000000000000" & uart_dat8;
-- BRAM Memory slave
bram0: entity work.mw_soc_memory
generic map(
MEMORY_SIZE => MEMORY_SIZE,
RAM_INIT_FILE => RAM_INIT_FILE
)
port map(
clk => system_clk,
rst => rst,
wishbone_in => wb_bram_in,
wishbone_out => wb_bram_out
);
end architecture behaviour;