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Pass wishbone record to bram memory module

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(And rename it to mw_soc_memory).

This makes soc.vhdl simpler and provides the same interface as
the simulated memory, which will help when sharing soc.vhdl
with sim later

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
pull/40/head
Benjamin Herrenschmidt 6 years ago
parent 1d66e1f981
commit d21ef5836d
4 changed files with 121 additions and 137 deletions
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108
fpga/mw_soc_memory.vhdl
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@ -0,0 +1,108 @@
-- Based on:
-- The Potato Processor - A simple processor for FPGAs
-- (c) Kristian Klomsten Skordal 2014 - 2015 <kristian.skordal@wafflemail.net>

library ieee;
use ieee.std_logic_1164.all;
use ieee.numeric_std.all;
use std.textio.all;

library work;
use work.wishbone_types.all;

use work.pp_utilities.all;

--! @brief Simple memory module for use in Wishbone-based systems.
entity mw_soc_memory is
generic(
MEMORY_SIZE : natural := 4096; --! Memory size in bytes.
RAM_INIT_FILE : string
);
port(
clk : in std_logic;
rst : in std_logic;

-- Wishbone interface:
wishbone_in : in wishbone_master_out;
wishbone_out : out wishbone_slave_out
);
end entity mw_soc_memory;

architecture behaviour of mw_soc_memory is
signal wb_adr_in : std_logic_vector(log2(MEMORY_SIZE) - 1 downto 0);
type ram_t is array(0 to (MEMORY_SIZE / 8) - 1) of std_logic_vector(63 downto 0);

impure function init_ram(name : STRING) return ram_t is
file ram_file : text open read_mode is name;
variable ram_line : line;
variable temp_word : std_logic_vector(63 downto 0);
variable temp_ram : ram_t := (others => (others => '0'));
begin
for i in 0 to (MEMORY_SIZE/8)-1 loop
exit when endfile(ram_file);
readline(ram_file, ram_line);
hread(ram_line, temp_word);
temp_ram(i) := temp_word;
end loop;

return temp_ram;
end function;

signal memory : ram_t := init_ram(RAM_INIT_FILE);

attribute ram_style : string;
attribute ram_style of memory : signal is "block";

attribute ram_decomp : string;
attribute ram_decomp of memory : signal is "power";

type state_type is (IDLE, ACK);
signal state : state_type;

signal read_ack : std_logic;

begin

wb_adr_in <= wishbone_in.adr(log2(MEMORY_SIZE) - 1 downto 0);

wishbone_out.ack <= read_ack and wishbone_in.stb;

memory_0: process(clk)
begin
if rising_edge(clk) then
if rst = '1' then
read_ack <= '0';
state <= IDLE;
else
if wishbone_in.cyc = '1' then
case state is
when IDLE =>
if wishbone_in.stb = '1' and wishbone_in.we = '1' then
for i in 0 to 7 loop
if wishbone_in.sel(i) = '1' then
memory(to_integer(unsigned(wb_adr_in(wb_adr_in'left downto 3))))(((i + 1) * 8) - 1 downto i * 8)
<= wishbone_in.dat(((i + 1) * 8) - 1 downto i * 8);
end if;
end loop;
read_ack <= '1';
state <= ACK;
elsif wishbone_in.stb = '1' then
wishbone_out.dat <= memory(to_integer(unsigned(wb_adr_in(wb_adr_in'left downto 3))));
read_ack <= '1';
state <= ACK;
end if;
when ACK =>
if wishbone_in.stb = '0' then
read_ack <= '0';
state <= IDLE;
end if;
end case;
else
state <= IDLE;
read_ack <= '0';
end if;
end if;
end if;
end process;

end architecture behaviour;

107
fpga/pp_soc_memory.vhd
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@ -1,107 +0,0 @@
-- The Potato Processor - A simple processor for FPGAs
-- (c) Kristian Klomsten Skordal 2014 - 2015 <kristian.skordal@wafflemail.net>

library ieee;
use ieee.std_logic_1164.all;
use ieee.numeric_std.all;
use std.textio.all;

use work.pp_utilities.all;

--! @brief Simple memory module for use in Wishbone-based systems.
entity pp_soc_memory is
generic(
MEMORY_SIZE : natural := 4096; --! Memory size in bytes.
RAM_INIT_FILE : string
);
port(
clk : in std_logic;
reset : in std_logic;

-- Wishbone interface:
wb_adr_in : in std_logic_vector(log2(MEMORY_SIZE) - 1 downto 0);
wb_dat_in : in std_logic_vector(63 downto 0);
wb_dat_out : out std_logic_vector(63 downto 0);
wb_cyc_in : in std_logic;
wb_stb_in : in std_logic;
wb_sel_in : in std_logic_vector( 7 downto 0);
wb_we_in : in std_logic;
wb_ack_out : out std_logic
);
end entity pp_soc_memory;

architecture behaviour of pp_soc_memory is
type ram_t is array(0 to (MEMORY_SIZE / 8) - 1) of std_logic_vector(63 downto 0);

impure function init_ram(name : STRING) return ram_t is
file ram_file : text open read_mode is name;
variable ram_line : line;
variable temp_word : std_logic_vector(63 downto 0);
variable temp_ram : ram_t := (others => (others => '0'));
begin
for i in 0 to (MEMORY_SIZE/8)-1 loop
exit when endfile(ram_file);
readline(ram_file, ram_line);
hread(ram_line, temp_word);
temp_ram(i) := temp_word;
end loop;

return temp_ram;
end function;

signal memory : ram_t := init_ram(RAM_INIT_FILE);

attribute ram_style : string;
attribute ram_style of memory : signal is "block";

attribute ram_decomp : string;
attribute ram_decomp of memory : signal is "power";

type state_type is (IDLE, ACK);
signal state : state_type;

signal read_ack : std_logic;

begin

wb_ack_out <= read_ack and wb_stb_in;

memory_0: process(clk)
begin
if rising_edge(clk) then
if reset = '1' then
read_ack <= '0';
state <= IDLE;
else
if wb_cyc_in = '1' then
case state is
when IDLE =>
if wb_stb_in = '1' and wb_we_in = '1' then
for i in 0 to 7 loop
if wb_sel_in(i) = '1' then
memory(to_integer(unsigned(wb_adr_in(wb_adr_in'left downto 3))))(((i + 1) * 8) - 1 downto i * 8)
<= wb_dat_in(((i + 1) * 8) - 1 downto i * 8);
end if;
end loop;
read_ack <= '1';
state <= ACK;
elsif wb_stb_in = '1' then
wb_dat_out <= memory(to_integer(unsigned(wb_adr_in(wb_adr_in'left downto 3))));
read_ack <= '1';
state <= ACK;
end if;
when ACK =>
if wb_stb_in = '0' then
read_ack <= '0';
state <= IDLE;
end if;
end case;
else
state <= IDLE;
read_ack <= '0';
end if;
end if;
end if;
end process;

end architecture behaviour;

41
fpga/soc.vhdl
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@ -46,14 +46,9 @@ architecture behaviour of soc is
signal uart0_ack_out : std_logic;

-- Main memory signals:
signal main_memory_adr_in : std_logic_vector(positive(ceil(log2(real(MEMORY_SIZE))))-1 downto 0);
signal main_memory_dat_in : std_logic_vector(63 downto 0);
signal main_memory_dat_out : std_logic_vector(63 downto 0);
signal main_memory_cyc_in : std_logic;
signal main_memory_stb_in : std_logic;
signal main_memory_sel_in : std_logic_vector(7 downto 0);
signal main_memory_we_in : std_logic;
signal main_memory_ack_out : std_logic;
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))));

begin

@ -82,8 +77,7 @@ begin
);

-- Wishbone slaves address decoder & mux
slave_intercon: process(wb_master_out,
main_memory_ack_out, main_memory_dat_out,
slave_intercon: process(wb_master_out, wb_bram_out,
uart0_ack_out, uart0_dat_out)
-- Selected slave
type slave_type is (SLAVE_UART,
@ -102,13 +96,13 @@ begin
end if;

-- Wishbone muxing. Defaults:
main_memory_cyc_in <= '0';
wb_bram_in <= wb_master_out;
wb_bram_in.cyc <= '0';
uart0_cyc_in <= '0';
case slave is
when SLAVE_MEMORY =>
main_memory_cyc_in <= wb_master_out.cyc;
wb_master_in.ack <= main_memory_ack_out;
wb_master_in.dat <= main_memory_dat_out;
wb_bram_in.cyc <= wb_master_out.cyc;
wb_master_in <= wb_bram_out;
when SLAVE_UART =>
uart0_cyc_in <= wb_master_out.cyc;
wb_master_in.ack <= uart0_ack_out;
@ -147,27 +141,16 @@ begin
uart0_stb_in <= wb_master_out.stb;

-- BRAM Memory slave
main_memory: entity work.pp_soc_memory
bram0: entity work.mw_soc_memory
generic map(
MEMORY_SIZE => MEMORY_SIZE,
RAM_INIT_FILE => RAM_INIT_FILE
)
port map(
clk => system_clk,
reset => rst,
wb_adr_in => main_memory_adr_in,
wb_dat_in => main_memory_dat_in,
wb_dat_out => main_memory_dat_out,
wb_cyc_in => main_memory_cyc_in,
wb_stb_in => main_memory_stb_in,
wb_sel_in => main_memory_sel_in,
wb_we_in => main_memory_we_in,
wb_ack_out => main_memory_ack_out
rst => rst,
wishbone_in => wb_bram_in,
wishbone_out => wb_bram_out
);
main_memory_adr_in <= wb_master_out.adr(main_memory_adr_in'range);
main_memory_dat_in <= wb_master_out.dat;
main_memory_we_in <= wb_master_out.we;
main_memory_sel_in <= wb_master_out.sel;
main_memory_stb_in <= wb_master_out.stb;

end architecture behaviour;

2
microwatt.core
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@ -32,7 +32,7 @@ filesets:
soc:
files:
- fpga/pp_fifo.vhd
- fpga/pp_soc_memory.vhd
- fpga/mw_soc_memory.vhdl
- fpga/soc_reset.vhdl
- fpga/pp_soc_uart.vhd
- fpga/pp_utilities.vhd

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