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added support for multi word writes

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This commit is contained in:
Erik Örtenberg 2025-02-27 16:11:16 +01:00
parent dd7683139c
commit 2149c1ec68
3 changed files with 110 additions and 55 deletions
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108
src/socbridge_driver.vhd
View File

@ -11,6 +11,7 @@ entity socbridge_driver is
clk : in std_logic;
rst : in std_logic;
cmd : in command_t;
cmd_size: in positive;
ext_in : in ext_socbridge_in_t;
ext_out : out ext_socbridge_out_t;
int_in : out int_socbridge_in_t;
@ -47,36 +48,36 @@ begin
ext_in_rec.clk <= ext_in.control(1);
ext_in_rec.parity <= ext_in.control(0);
comb_proc: process(ext_in, int_out, st)
-- Helpful Bindings --
curr_response_bits <= ext_in.payload(7 downto 3); -- CANT USE EXT_IN_REC here for some reason, the assignment becomes stasteful
-- Not sure that the two process method is helping here: if this was a normal
-- signal assignment there would be no confusion.
-- in the case ... <= ext_in_rec we get
-- curr_resp | ext_in_rec | ext_in
-- 00000 | 00000000 | 00001001
-- 00000 | 00001001 | 00001001
-- 00001 | 00001001 | 00001001
-- 00001 | 00001001 | 00001001
--
-- but in the case ... <= ext_in we get
-- curr_resp | ext_in_rec | ext_in
-- 00000 | 00000000 | 00001001
-- 00001 | 00001001 | 00001001
-- 00001 | 00001001 | 00001001
-- 00001 | 00001001 | 00001001
with curr_response_bits select
curr_response <= WRITE_ACK when "00001",
WRITE_ACK when "00101",
READ_RESPONSE when "01000",
READ_RESPONSE when "01100",
NO_OP when others;
comb_proc: process(ext_in, int_out, curr_response, st)
begin
-- Outputs
ext_out <= create_io_type_out_from_ext_protocol(st.ext_out_reg);
int_in.payload <= st.ext_in_reg.data;
-- Helpful Bindings --
curr_response_bits <= ext_in.payload(7 downto 3); -- CANT USE EXT_IN_REC here for some reason, the assignment becomes stasteful
-- Not sure that the two process method is helping here: if this was a normal
-- signal assignment there would be no confusion.
-- in the case ... <= ext_in_rec we get
-- curr_resp | ext_in_rec | ext_in
-- 00000 | 00000000 | 00001001
-- 00000 | 00001001 | 00001001
-- 00001 | 00001001 | 00001001
-- 00001 | 00001001 | 00001001
--
-- but in the case ... <= ext_in we get
-- curr_resp | ext_in_rec | ext_in
-- 00000 | 00000000 | 00001001
-- 00001 | 00001001 | 00001001
-- 00001 | 00001001 | 00001001
-- 00001 | 00001001 | 00001001
with curr_response_bits select
curr_response <= WRITE_ACK when "00001",
WRITE_ACK when "00101",
READ_RESPONSE when "01000",
READ_RESPONSE when "01100",
NO_OP when others;
--- State Transition Diagram ---
--
@ -122,7 +123,11 @@ begin
when TX_BODY =>
-- Here we want to stay in TX_BODY for the duration of a packet.
-- Right now, we transfer one single word at a time for simplicity
next_state <= TX_ACK;
if st.write_stage = 0 then
next_state <= TX_ACK;
else
next_state <= TX_BODY;
end if;
when TX_ACK =>
-- Wait for write acknowledgement.
if curr_response = WRITE_ACK then
@ -154,25 +159,31 @@ begin
case st.curr_state is
when IDLE =>
if cmd = WRITE or cmd = WRITE_ADD then
ext_out_data_cmd := get_command_bits(WRITE) & "001";
curr_command <= cmd;
ext_out_data_cmd := get_command_bits(cmd) & get_size_bits(cmd_size);
elsif cmd = READ or cmd = READ_ADD then
ext_out_data_cmd := get_command_bits(READ) & "001";
curr_command <= cmd;
ext_out_data_cmd := get_command_bits(cmd) & get_size_bits(cmd_size);
end if;
when RESET =>
when TX_HEADER =>
curr_command <= WRITE;
ext_out_data_cmd := int_out.payload;
if cmd = WRITE_ADD then
--ext_out_data_cmd := address;
else
ext_out_data_cmd := int_out.payload;
end if;
int_in.is_full_out <= '0';
when TX_BODY =>
-- here more logic is needed for mulit word transmission (and address setting)
if cmd = WRITE_ADD then
if curr_response = WRITE_ACK then
ext_out_data_cmd := "00000000";
else
ext_out_data_cmd := int_out.payload;
int_in.is_full_out <= '0';
end if;
when TX_ACK =>
when RX_HEADER =>
curr_command <= READ;
ext_out_data_cmd := curr_command_bits & "001";
ext_out_data_cmd := curr_command_bits & get_size_bits(cmd_size);
when RX_RESPONSE =>
when RX_BODY =>
end case;
@ -180,9 +191,6 @@ begin
--- DEBUG GLOBAL BINDINGS ---
-- synthesis translate_off
test <= ext_out_data_cmd;
report to_string(ext_out_data_cmd);
report to_string(test);
report to_string(G_ext_out_data_cmd);
-- synthesis translate_on
end process comb_proc;
-- Process updating internal registers based on primary clock
@ -194,6 +202,8 @@ begin
st.ext_out_reg.clk <= '0';
st.ext_out_reg.parity <= '1';
st.curr_state <= IDLE;
st.write_stage <= 0;
st.read_stage <= 0;
elsif(rising_edge(ext_in_rec.clk)) then
st.ext_in_reg.data <= ext_in_rec.data;
@ -203,7 +213,31 @@ begin
st.ext_out_reg.clk <= not st.ext_out_reg.clk;
st.ext_out_reg.parity <= next_parity_out;
st.curr_state <= next_state;
end if;
case st.curr_state is
when TX_HEADER =>
if curr_command = WRITE then
st.write_stage <= 2**(cmd_size - 1) - 1;
elsif curr_command = WRITE_ADD then
st.write_stage <= 2**(cmd_size - 1);
end if;
when TX_BODY =>
if st.write_stage > 0 then
st.write_stage <= st.write_stage - 1;
end if;
when RX_HEADER =>
if curr_command = READ then
st.read_stage <= 2**(cmd_size - 1) - 1;
elsif curr_command = WRITE_ADD then
st.read_stage <= 2**(cmd_size - 1);
end if;
when RX_BODY =>
if st.read_stage > 0 then
st.read_stage <= st.read_stage - 1;
end if;
when others =>
end case;
end if;
end process seq_proc;

33
src/socbridge_driver_tb.vhd
View File

@ -13,6 +13,7 @@ architecture tb of socbridge_driver_tb is
signal clk : std_logic := '0';
signal rst : std_logic;
signal cmd : command_t;
signal cmd_size : positive;
signal ext_in : ext_socbridge_in_t;
signal ext_out : ext_socbridge_out_t;
signal int_in : int_socbridge_in_t;
@ -61,6 +62,7 @@ architecture tb of socbridge_driver_tb is
clk : in std_logic;
rst : in std_logic;
cmd : in command_t;
cmd_size: in positive;
ext_in : in ext_socbridge_in_t;
ext_out : out ext_socbridge_out_t;
int_in : out int_socbridge_in_t;
@ -74,6 +76,7 @@ begin
clk => clk,
rst => rst,
cmd => cmd,
cmd_size => cmd_size,
ext_in => ext_in,
ext_out => ext_out,
int_in => int_in,
@ -127,13 +130,13 @@ begin
wait for CLK_PERIOD /4;
check_next_state(TX_HEADER);
wait for CLK_PERIOD * 3 / 4;
expected_out <= get_command_bits(WRITE) & "001";
expected_out <= get_command_bits(WRITE) & get_size_bits_sim(2);
check_next_state(TX_BODY);
wait for CLK_PERIOD;
expected_out <= "00000001";
check_next_state(TX_ACK);
check_next_state(TX_BODY);
wait for CLK_PERIOD;
expected_out <= "00000000";
expected_out <= "00000010";
check_next_state(TX_ACK);
wait for CLK_PERIOD;
expected_out <= "00000000";
@ -166,6 +169,7 @@ begin
command_stimulus: process
begin
cmd <= NO_OP;
cmd_size <= 2;
wait for 3*CLK_PERIOD;
wait for CLK_PERIOD / 2;
cmd <= WRITE;
@ -203,24 +207,17 @@ begin
-- stimulus goes here
int_out.write_enable_out <= '1';
int_out.payload <= "00000001";
wait until int_in.is_full_out = '0';
wait until rising_edge(clk);
wait until rising_edge(clk);
wait until rising_edge(clk) and int_in.is_full_out = '0';
wait until falling_edge(clk);
int_out.payload <= "00000010";
wait until int_in.is_full_out = '0';
wait for CLK_PERIOD/2;
wait until rising_edge(clk);
wait until rising_edge(clk);
wait until rising_edge(clk) and int_in.is_full_out = '0';
wait until falling_edge(clk);
int_out.payload <= "00000100";
wait until int_in.is_full_out = '0';
wait for CLK_PERIOD/2;
wait until rising_edge(clk);
wait until rising_edge(clk);
wait until rising_edge(clk) and int_in.is_full_out = '0';
wait until falling_edge(clk);
int_out.payload <= "00001000";
wait until int_in.is_full_out = '0';
wait for CLK_PERIOD/2;
wait until rising_edge(clk);
wait until rising_edge(clk);
wait until rising_edge(clk) and int_in.is_full_out = '0';
wait until falling_edge(clk);
int_out.payload <= "00010000";
wait until int_in.is_full_out = '0';
wait for CLK_PERIOD/2;

24
src/socbridge_driver_tb_pkg.vhd
View File

@ -1,10 +1,14 @@
library IEEE;
use IEEE.std_logic_1164.all;
use IEEE.numeric_std.all;
use IEEE.MATH_REAL.all;
library work;
use work.io_types.all;
package socbridge_driver_tb_pkg is
subtype command_size_t is integer range 1 to 128;
type command_t is
(NO_OP, WRITE_ADD, WRITE, READ_ADD, READ, P_ERR);
@ -23,6 +27,7 @@ package socbridge_driver_tb_pkg is
type state_rec_t is record
curr_state: state_t;
ext_in_reg, ext_out_reg : ext_protocol_t;
write_stage, read_stage : NATURAL;
end record state_rec_t;
impure function calc_parity(
d : STD_LOGIC_VECTOR(interface_inst.socbridge.payload_width - 1 downto 0)
@ -32,6 +37,8 @@ package socbridge_driver_tb_pkg is
) return ext_socbridge_out_t;
function to_string ( a: std_logic_vector) return string;
pure function get_command_bits(command : command_t) return std_logic_vector;
pure function get_size_bits(size : command_size_t) return std_logic_vector;
pure function get_size_bits_sim(size : command_size_t) return std_logic_vector;
--- DEBUG GLOBAL SIGNALS ---
-- synthesis translate_off
signal G_next_parity_out : std_logic;
@ -96,4 +103,21 @@ package body socbridge_driver_tb_pkg is
return val;
end function;
pure function get_size_bits(size: command_size_t)
return std_logic_vector is
variable val : std_logic_vector(2 downto 0);
begin
val := std_logic_vector(TO_UNSIGNED(size - 1, 3));
return val;
end function;
pure function get_size_bits_sim(size: command_size_t)
return std_logic_vector is
variable pow : integer;
variable val : std_logic_vector(2 downto 0);
begin
pow := integer(CEIL(sqrt(Real(size))));
val := std_logic_vector(TO_UNSIGNED(size - 1, 3));
return val;
end function;
end package body socbridge_driver_tb_pkg;