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litedram: l2: Add support for more geometries

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Make the DRAM data lines and user port width configurable, also
don't hard wire dependency on the wishbone data width.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This commit is contained in:
Benjamin Herrenschmidt
2020-06-24 12:02:55 +10:00
parent 1441b2a859
commit 02abb135a8
5 changed files with 83 additions and 45 deletions
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2
core_dram_tb.vhdl
View File

@@ -120,6 +120,8 @@ begin
generic map(
DRAM_ABITS => 24,
DRAM_ALINES => 1,
DRAM_DLINES => 16,
DRAM_PORT_WIDTH => 128,
PAYLOAD_FILE => DRAM_INIT_FILE,
PAYLOAD_SIZE => ROM_SIZE
)

2
dram_tb.vhdl
View File

@@ -43,6 +43,8 @@ begin
generic map(
DRAM_ABITS => 24,
DRAM_ALINES => 1,
DRAM_DLINES => 16,
DRAM_PORT_WIDTH => 128,
PAYLOAD_FILE => DRAM_INIT_FILE,
PAYLOAD_SIZE => DRAM_INIT_SIZE
)

2
fpga/top-arty.vhdl
View File

@@ -341,6 +341,8 @@ begin
generic map(
DRAM_ABITS => 24,
DRAM_ALINES => 14,
DRAM_DLINES => 16,
DRAM_PORT_WIDTH => 128,
PAYLOAD_FILE => RAM_INIT_FILE,
PAYLOAD_SIZE => PAYLOAD_SIZE
)

2
fpga/top-nexys-video.vhdl
View File

@@ -258,6 +258,8 @@ begin
generic map(
DRAM_ABITS => 25,
DRAM_ALINES => 15,
DRAM_DLINES => 16,
DRAM_PORT_WIDTH => 128,
PAYLOAD_FILE => RAM_INIT_FILE,
PAYLOAD_SIZE => PAYLOAD_SIZE
)

120
litedram/extras/litedram-wrapper-l2.vhdl
View File

@@ -10,8 +10,10 @@ use work.helpers.all;
entity litedram_wrapper is
generic (
DRAM_ABITS : positive;
DRAM_ALINES : positive;
DRAM_ABITS : positive;
DRAM_ALINES : natural;
DRAM_DLINES : natural;
DRAM_PORT_WIDTH : positive;
-- Pseudo-ROM payload
PAYLOAD_SIZE : natural;
@@ -63,10 +65,10 @@ entity litedram_wrapper is
ddram_cas_n : out std_ulogic;
ddram_we_n : out std_ulogic;
ddram_cs_n : out std_ulogic;
ddram_dm : out std_ulogic_vector(1 downto 0);
ddram_dq : inout std_ulogic_vector(15 downto 0);
ddram_dqs_p : inout std_ulogic_vector(1 downto 0);
ddram_dqs_n : inout std_ulogic_vector(1 downto 0);
ddram_dm : out std_ulogic_vector(DRAM_DLINES/8-1 downto 0);
ddram_dq : inout std_ulogic_vector(DRAM_DLINES-1 downto 0);
ddram_dqs_p : inout std_ulogic_vector(DRAM_DLINES/8-1 downto 0);
ddram_dqs_n : inout std_ulogic_vector(DRAM_DLINES/8-1 downto 0);
ddram_clk_p : out std_ulogic;
ddram_clk_n : out std_ulogic;
ddram_cke : out std_ulogic;
@@ -87,10 +89,10 @@ architecture behaviour of litedram_wrapper is
ddram_cas_n : out std_ulogic;
ddram_we_n : out std_ulogic;
ddram_cs_n : out std_ulogic;
ddram_dm : out std_ulogic_vector(1 downto 0);
ddram_dq : inout std_ulogic_vector(15 downto 0);
ddram_dqs_p : inout std_ulogic_vector(1 downto 0);
ddram_dqs_n : inout std_ulogic_vector(1 downto 0);
ddram_dm : out std_ulogic_vector(DRAM_DLINES/8-1 downto 0);
ddram_dq : inout std_ulogic_vector(DRAM_DLINES-1 downto 0);
ddram_dqs_p : inout std_ulogic_vector(DRAM_DLINES/8-1 downto 0);
ddram_dqs_n : inout std_ulogic_vector(DRAM_DLINES/8-1 downto 0);
ddram_clk_p : out std_ulogic;
ddram_clk_n : out std_ulogic;
ddram_cke : out std_ulogic;
@@ -117,11 +119,11 @@ architecture behaviour of litedram_wrapper is
user_port_native_0_cmd_addr : in std_ulogic_vector(DRAM_ABITS-1 downto 0);
user_port_native_0_wdata_valid : in std_ulogic;
user_port_native_0_wdata_ready : out std_ulogic;
user_port_native_0_wdata_we : in std_ulogic_vector(15 downto 0);
user_port_native_0_wdata_data : in std_ulogic_vector(127 downto 0);
user_port_native_0_wdata_we : in std_ulogic_vector(DRAM_PORT_WIDTH/8-1 downto 0);
user_port_native_0_wdata_data : in std_ulogic_vector(DRAM_PORT_WIDTH-1 downto 0);
user_port_native_0_rdata_valid : out std_ulogic;
user_port_native_0_rdata_ready : in std_ulogic;
user_port_native_0_rdata_data : out std_ulogic_vector(127 downto 0)
user_port_native_0_rdata_data : out std_ulogic_vector(DRAM_PORT_WIDTH-1 downto 0)
);
end component;
@@ -131,11 +133,11 @@ architecture behaviour of litedram_wrapper is
signal user_port0_cmd_addr : std_ulogic_vector(DRAM_ABITS-1 downto 0);
signal user_port0_wdata_valid : std_ulogic;
signal user_port0_wdata_ready : std_ulogic;
signal user_port0_wdata_we : std_ulogic_vector(15 downto 0);
signal user_port0_wdata_data : std_ulogic_vector(127 downto 0);
signal user_port0_wdata_we : std_ulogic_vector(DRAM_PORT_WIDTH/8-1 downto 0);
signal user_port0_wdata_data : std_ulogic_vector(DRAM_PORT_WIDTH-1 downto 0);
signal user_port0_rdata_valid : std_ulogic;
signal user_port0_rdata_ready : std_ulogic;
signal user_port0_rdata_data : std_ulogic_vector(127 downto 0);
signal user_port0_rdata_data : std_ulogic_vector(DRAM_PORT_WIDTH-1 downto 0);
signal wb_ctrl_adr : std_ulogic_vector(29 downto 0);
signal wb_ctrl_dat_w : std_ulogic_vector(31 downto 0);
@@ -150,14 +152,24 @@ architecture behaviour of litedram_wrapper is
signal wb_init_out : wb_io_slave_out;
-- DRAM data port width
constant DRAM_DBITS : natural := 128;
constant DRAM_DBITS : natural := DRAM_PORT_WIDTH;
-- DRAM data port sel bits
constant DRAM_SBITS : natural := (DRAM_DBITS / 8);
-- WB geometry (just a few shortcuts)
constant WBL : positive := wb_in.dat'length;
constant WBSL : positive := wb_in.sel'length;
-- Select a WB word inside DRAM port width
constant WB_WORD_COUNT : positive := DRAM_DBITS/WBL;
constant WB_WSEL_BITS : positive := log2(WB_WORD_COUNT);
constant WB_WSEL_RIGHT : positive := log2(WBL/8);
-- BRAM organisation: We never access more than wishbone_data_bits at
-- a time so to save resources we make the array only that wide, and
-- use consecutive indices for to make a cache "line"
--
-- ROW_SIZE is the width in bytes of the BRAM (based on litedram, so 128-bits)
-- ROW_SIZE is the width in bytes of the BRAM, ie, litedram port width
constant ROW_SIZE : natural := DRAM_DBITS / 8;
-- ROW_PER_LINE is the number of row (litedram transactions) in a line
constant ROW_PER_LINE : natural := LINE_SIZE / ROW_SIZE;
@@ -184,7 +196,7 @@ architecture behaviour of litedram_wrapper is
-- TAG_BITS is the number of bits of the tag part of the address
constant TAG_BITS : natural := REAL_ADDR_BITS - SET_SIZE_BITS;
-- WAY_BITS is the number of bits to select a way
constant WAY_BITS : natural := log2(NUM_WAYS);
constant WAY_BITS : natural := log2(NUM_WAYS);
subtype row_t is integer range 0 to BRAM_ROWS-1;
subtype index_t is integer range 0 to NUM_LINES-1;
@@ -221,10 +233,10 @@ architecture behaviour of litedram_wrapper is
--
-- Store queue signals
--
-- We store a single wishbone dword per entry (64-bit) but all
-- 16 sel bits for the DRAM.
-- XXX Investigate storing only AD3 and 8 sel bits if it's better
constant STOREQ_BITS : positive := wishbone_data_bits + DRAM_SBITS;
-- We store a single wishbone dword per entry (64-bit)
-- along with the wishbone sel bits and the necessary address
-- bits to select which part of DRAM port to write to.
constant STOREQ_BITS : positive := WBL + WBSL + WB_WSEL_BITS;
signal storeq_rd_ready : std_ulogic;
signal storeq_rd_valid : std_ulogic;
@@ -251,8 +263,8 @@ architecture behaviour of litedram_wrapper is
-- Read pipeline (to handle cache RAM latency)
signal read_ack_0 : std_ulogic := '0';
signal read_ack_1 : std_ulogic := '0';
signal read_ad3_0 : std_ulogic;
signal read_ad3_1 : std_ulogic;
signal read_wsl_0 : std_ulogic_vector(WB_WSEL_BITS-1 downto 0) := (others => '0');
signal read_wsl_1 : std_ulogic_vector(WB_WSEL_BITS-1 downto 0) := (others => '0');
signal read_way_0 : way_t;
signal read_way_1 : way_t;
@@ -274,7 +286,7 @@ architecture behaviour of litedram_wrapper is
signal req_tag : cache_tag_t;
signal req_op : req_op_t;
signal req_laddr : std_ulogic_vector(REAL_ADDR_BITS-1 downto 0);
signal req_ad3 : std_ulogic;
signal req_wsl : std_ulogic_vector(WB_WSEL_BITS-1 downto 0);
signal req_we : std_ulogic_vector(DRAM_SBITS-1 downto 0);
signal req_wdata : std_ulogic_vector(DRAM_DBITS-1 downto 0);
signal stall : std_ulogic;
@@ -397,8 +409,6 @@ begin
report "geometry bits don't add up" severity FAILURE;
assert (REAL_ADDR_BITS = TAG_BITS + ROW_BITS + ROW_OFF_BITS)
report "geometry bits don't add up" severity FAILURE;
assert (128 = DRAM_DBITS)
report "Can't yet handle a DRAM width that isn't 128-bits" severity FAILURE;
-- alternate core reset address set when DRAM is not initialized.
core_alt_reset <= not init_done;
@@ -646,11 +656,11 @@ begin
begin
if rising_edge(system_clk) then
read_ack_0 <= '1' when req_op = OP_LOAD_HIT else '0';
read_ad3_0 <= req_ad3;
read_wsl_0 <= req_wsl;
read_way_0 <= req_hit_way;
read_ack_1 <= read_ack_0;
read_ad3_1 <= read_ad3_0;
read_wsl_1 <= read_wsl_0;
read_way_1 <= read_way_0;
if TRACE then
@@ -683,10 +693,11 @@ begin
-- Wishbone response generation
--
wb_reponse: process(all)
wb_rseponse: process(all)
variable rdata : std_ulogic_vector(DRAM_DBITS-1 downto 0);
variable store_done : std_ulogic;
variable accept_store : std_ulogic;
variable wsel : natural range 0 to WB_WORD_COUNT-1;
begin
-- Can we accept a store ? This is set when the store queue & command
-- queue are not full.
@@ -722,7 +733,10 @@ begin
-- Data out mux
rdata := cache_out(read_way_1);
wb_out.dat <= rdata(127 downto 64) when read_ad3_1 = '1' else rdata(63 downto 0);
-- Hard wired for 64-bit wishbone
wsel := to_integer(unsigned(read_wsl_1));
wb_out.dat <= rdata((wsel+1)*WBL-1 downto wsel*WBL);
-- Early-complete stores on wishbone.
if req_op = OP_STORE_HIT or req_op = OP_STORE_MISS then
@@ -769,11 +783,16 @@ begin
-- Do we have a valid request in the WB latch ?
valid := wb_req.cyc = '1' and wb_req.stb = '1';
-- Store signals
req_ad3 <= wb_req.adr(3);
req_wdata <= wb_req.dat & wb_req.dat;
req_we <= wb_req.sel & "00000000" when req_ad3 = '1' else
"00000000" & wb_req.sel;
-- Store signals (hard wired for 64-bit wishbone at the moment)
req_wsl <= wb_req.adr(WB_WSEL_RIGHT+WB_WSEL_BITS-1 downto WB_WSEL_RIGHT);
for i in 0 to WB_WORD_COUNT-1 loop
if to_integer(unsigned(req_wsl)) = i then
req_we(WBSL*(i+1)-1 downto WBSL*i) <= wb_req.sel;
else
req_we(WBSL*(i+1)-1 downto WBSL*i) <= x"00";
end if;
req_wdata(WBL*(i+1)-1 downto WBL*i) <= wb_req.dat;
end loop;
-- Test if pending request is a hit on any way
hit_way := 0;
@@ -869,9 +888,11 @@ begin
storeq_control : process(all)
variable stq_data : wishbone_data_type;
variable stq_sel : std_ulogic_vector(DRAM_SBITS-1 downto 0);
variable stq_sel : wishbone_sel_type;
variable stq_wsl : std_ulogic_vector(WB_WSEL_BITS-1 downto 0);
begin
storeq_wr_data <= wb_req.dat & req_we;
storeq_wr_data <= wb_req.dat & wb_req.sel &
wb_req.adr(WB_WSEL_RIGHT+WB_WSEL_BITS-1 downto WB_WSEL_RIGHT);
-- Only queue stores if we can also send a command
if req_op = OP_STORE_HIT or req_op = OP_STORE_MISS then
@@ -880,10 +901,19 @@ begin
storeq_wr_valid <= '0';
end if;
stq_data := storeq_rd_data(storeq_rd_data'left downto DRAM_SBITS);
stq_sel := storeq_rd_data(DRAM_SBITS-1 downto 0);
user_port0_wdata_data <= stq_data & stq_data;
user_port0_wdata_we <= stq_sel;
-- Store signals (hard wired for 64-bit wishbone at the moment)
stq_data := storeq_rd_data(storeq_rd_data'left downto WBSL+WB_WSEL_BITS);
stq_sel := storeq_rd_data(WBSL+WB_WSEL_BITS-1 downto WB_WSEL_BITS);
stq_wsl := storeq_rd_data(WB_WSEL_BITS-1 downto 0);
for i in 0 to WB_WORD_COUNT-1 loop
if to_integer(unsigned(stq_wsl)) = i then
user_port0_wdata_we(WBSL*(i+1)-1 downto WBSL*i) <= stq_sel;
else
user_port0_wdata_we(WBSL*(i+1)-1 downto WBSL*i) <= x"00";
end if;
user_port0_wdata_data(WBL*(i+1)-1 downto WBL*i) <= stq_data;
end loop;
user_port0_wdata_valid <= storeq_rd_valid;
storeq_rd_ready <= user_port0_wdata_ready;
@@ -918,7 +948,7 @@ begin
if req_op = OP_STORE_HIT or req_op = OP_STORE_MISS then
-- For stores, forward signals directly. Only send command if
-- the FIFO can accept a store.
user_port0_cmd_addr <= wb_req.adr(DRAM_ABITS+3 downto 4);
user_port0_cmd_addr <= wb_req.adr(DRAM_ABITS+ROW_OFF_BITS-1 downto ROW_OFF_BITS);
user_port0_cmd_we <= '1';
user_port0_cmd_valid <= storeq_wr_ready;
else
@@ -983,7 +1013,7 @@ begin
-- "dram_commands". In fact, we could make refill_cmd_addr
-- only contain the "counter" bits and wire it with the
-- other bits from req_laddr.
refill_cmd_addr <= req_laddr(DRAM_ABITS+3 downto 4);
refill_cmd_addr <= req_laddr(DRAM_ABITS+ROW_OFF_BITS-1 downto ROW_OFF_BITS);
refill_cmd_valid <= '1';
if TRACE then