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Merge pull request #335 from ozbenh/misc

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Misc cleanups and icache fix
boxarty-20211011
Anton Blanchard 3 years ago committed by GitHub
parent 13439c76ba e675eba0df
commit 099862bee9
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
4 changed files with 60 additions and 37 deletions
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11
common.vhdl
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@ -156,6 +156,12 @@ package common is
constant FPSCR_NI : integer := 63 - 61;
constant FPSCR_RN : integer := 63 - 63;

-- Real addresses
-- REAL_ADDR_BITS is the number of real address bits that we store
constant REAL_ADDR_BITS : positive := 56;
subtype real_addr_t is std_ulogic_vector(REAL_ADDR_BITS - 1 downto 0);
function addr_to_real(addr: std_ulogic_vector(63 downto 0)) return real_addr_t;

-- Used for tracking instruction completion and pending register writes
constant TAG_COUNT : positive := 4;
constant TAG_NUMBER_BITS : natural := log2(TAG_COUNT);
@ -779,4 +785,9 @@ package body common is
begin
return tag1.valid = '1' and tag2.valid = '1' and tag1.tag = tag2.tag;
end;

function addr_to_real(addr: std_ulogic_vector(63 downto 0)) return real_addr_t is
begin
return addr(real_addr_t'range);
end;
end common;

23
dcache.vhdl
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@ -67,8 +67,6 @@ architecture rtl of dcache is

-- Bit fields counts in the address

-- REAL_ADDR_BITS is the number of real address bits that we store
constant REAL_ADDR_BITS : positive := 56;
-- ROW_BITS is the number of bits to select a row
constant ROW_BITS : natural := log2(BRAM_ROWS);
-- ROW_LINEBITS is the number of bits to select a row within a line
@ -289,7 +287,7 @@ architecture rtl of dcache is
op : op_t;
valid : std_ulogic;
dcbz : std_ulogic;
real_addr : std_ulogic_vector(REAL_ADDR_BITS - 1 downto 0);
real_addr : real_addr_t;
data : std_ulogic_vector(63 downto 0);
byte_sel : std_ulogic_vector(7 downto 0);
hit_way : way_t;
@ -412,7 +410,7 @@ architecture rtl of dcache is
signal tlb_hit : std_ulogic;
signal tlb_hit_way : tlb_way_t;
signal pte : tlb_pte_t;
signal ra : std_ulogic_vector(REAL_ADDR_BITS - 1 downto 0);
signal ra : real_addr_t;
signal valid_ra : std_ulogic;
signal perm_attr : perm_attr_t;
signal rc_ok : std_ulogic;
@ -454,7 +452,7 @@ architecture rtl of dcache is
end;

-- Returns whether this is the last row of a line
function is_last_row_addr(addr: wishbone_addr_type; last: row_in_line_t) return boolean is
function is_last_row_wb_addr(addr: wishbone_addr_type; last: row_in_line_t) return boolean is
begin
return unsigned(addr(LINE_OFF_BITS - ROW_OFF_BITS - 1 downto 0)) = last;
end;
@ -466,7 +464,7 @@ architecture rtl of dcache is
end;

-- Return the address of the next row in the current cache line
function next_row_addr(addr: wishbone_addr_type) return std_ulogic_vector is
function next_row_wb_addr(addr: wishbone_addr_type) return std_ulogic_vector is
variable row_idx : std_ulogic_vector(ROW_LINEBITS-1 downto 0);
variable result : wishbone_addr_type;
begin
@ -803,11 +801,10 @@ begin

-- Cache tag RAM second read port, for snooping
cache_tag_read_2 : process(clk)
variable addr : std_ulogic_vector(REAL_ADDR_BITS - 1 downto 0);
variable addr : real_addr_t;
begin
if rising_edge(clk) then
addr := (others => '0');
addr(snoop_in.adr'left + ROW_OFF_BITS downto ROW_OFF_BITS) := snoop_in.adr;
addr := addr_to_real(wb_to_addr(snoop_in.adr));
snoop_tag_set <= cache_tags(get_index(addr));
snoop_wrtag <= get_tag(addr);
snoop_index <= get_index(addr);
@ -830,7 +827,7 @@ begin
variable s_hit : std_ulogic;
variable s_tag : cache_tag_t;
variable s_pte : tlb_pte_t;
variable s_ra : std_ulogic_vector(REAL_ADDR_BITS - 1 downto 0);
variable s_ra : real_addr_t;
variable hit_set : std_ulogic_vector(TLB_NUM_WAYS - 1 downto 0);
variable hit_way_set : hit_way_set_t;
variable rel_matches : std_ulogic_vector(TLB_NUM_WAYS - 1 downto 0);
@ -1383,7 +1380,7 @@ begin
-- Main state machine
case r1.state is
when IDLE =>
r1.wb.adr <= req.real_addr(r1.wb.adr'left + ROW_OFF_BITS downto ROW_OFF_BITS);
r1.wb.adr <= addr_to_wb(req.real_addr);
r1.wb.sel <= req.byte_sel;
r1.wb.dat <= req.data;
r1.dcbz <= req.dcbz;
@ -1471,12 +1468,12 @@ begin
-- If we are still sending requests, was one accepted ?
if wishbone_in.stall = '0' and r1.wb.stb = '1' then
-- That was the last word ? We are done sending. Clear stb.
if is_last_row_addr(r1.wb.adr, r1.end_row_ix) then
if is_last_row_wb_addr(r1.wb.adr, r1.end_row_ix) then
r1.wb.stb <= '0';
end if;

-- Calculate the next row address
r1.wb.adr <= next_row_addr(r1.wb.adr);
r1.wb.adr <= next_row_wb_addr(r1.wb.adr);
end if;

-- Incoming acks processing

43
icache.vhdl
Unescape Escape View File

@ -46,8 +46,6 @@ entity icache is
TLB_SIZE : positive := 64;
-- L1 ITLB log_2(page_size)
TLB_LG_PGSZ : positive := 12;
-- Number of real address bits that we store
REAL_ADDR_BITS : positive := 56;
-- Non-zero to enable log data collection
LOG_LENGTH : natural := 0
);
@ -207,10 +205,10 @@ architecture rtl of icache is
signal req_tag : cache_tag_t;
signal req_is_hit : std_ulogic;
signal req_is_miss : std_ulogic;
signal req_laddr : std_ulogic_vector(63 downto 0);
signal req_raddr : real_addr_t;

signal tlb_req_index : tlb_index_t;
signal real_addr : std_ulogic_vector(REAL_ADDR_BITS - 1 downto 0);
signal real_addr : real_addr_t;
signal ra_valid : std_ulogic;
signal priv_fault : std_ulogic;
signal access_ok : std_ulogic;
@ -251,9 +249,9 @@ architecture rtl of icache is
end;

-- Returns whether this is the last row of a line
function is_last_row_addr(addr: wishbone_addr_type; last: row_in_line_t) return boolean is
function is_last_row_wb_addr(wb_addr: wishbone_addr_type; last: row_in_line_t) return boolean is
begin
return unsigned(addr(LINE_OFF_BITS - ROW_OFF_BITS - 1 downto 0)) = last;
return unsigned(wb_addr(LINE_OFF_BITS - ROW_OFF_BITS - 1 downto 0)) = last;
end;

-- Returns whether this is the last row of a line
@ -263,15 +261,15 @@ architecture rtl of icache is
end;

-- Return the address of the next row in the current cache line
function next_row_addr(addr: wishbone_addr_type)
function next_row_wb_addr(wb_addr: wishbone_addr_type)
return std_ulogic_vector is
variable row_idx : std_ulogic_vector(ROW_LINEBITS-1 downto 0);
variable result : wishbone_addr_type;
begin
-- Is there no simpler way in VHDL to generate that 3 bits adder ?
row_idx := addr(ROW_LINEBITS - 1 downto 0);
row_idx := wb_addr(ROW_LINEBITS - 1 downto 0);
row_idx := std_ulogic_vector(unsigned(row_idx) + 1);
result := addr;
result := wb_addr;
result(ROW_LINEBITS - 1 downto 0) := row_idx;
return result;
end;
@ -301,10 +299,9 @@ architecture rtl of icache is
end;

-- Get the tag value from the address
function get_tag(addr: std_ulogic_vector(REAL_ADDR_BITS - 1 downto 0);
endian: std_ulogic) return cache_tag_t is
function get_tag(addr: real_addr_t; endian: std_ulogic) return cache_tag_t is
begin
return endian & addr(REAL_ADDR_BITS - 1 downto SET_SIZE_BITS);
return endian & addr(addr'left downto SET_SIZE_BITS);
end;

-- Read a tag from a tag memory row
@ -468,7 +465,7 @@ begin
end if;
eaa_priv <= pte(3);
else
real_addr <= i_in.nia(REAL_ADDR_BITS - 1 downto 0);
real_addr <= addr_to_real(i_in.nia);
ra_valid <= '1';
eaa_priv <= '1';
end if;
@ -524,8 +521,7 @@ begin
-- Calculate address of beginning of cache row, will be
-- used for cache miss processing if needed
--
req_laddr <= (63 downto REAL_ADDR_BITS => '0') &
real_addr(REAL_ADDR_BITS - 1 downto ROW_OFF_BITS)&
req_raddr <= real_addr(REAL_ADDR_BITS - 1 downto ROW_OFF_BITS) &
(ROW_OFF_BITS-1 downto 0 => '0');

-- Test if pending request is a hit on any way
@ -627,7 +623,7 @@ begin
icache_miss : process(clk)
variable tagset : cache_tags_set_t;
variable tag : cache_tag_t;
variable snoop_addr : std_ulogic_vector(REAL_ADDR_BITS - 1 downto 0);
variable snoop_addr : real_addr_t;
variable snoop_tag : cache_tag_t;
variable snoop_cache_tags : cache_tags_set_t;
begin
@ -657,8 +653,7 @@ begin
-- Detect snooped writes and decode address into index and tag
-- Since we never write, any write should be snooped
snoop_valid <= wb_snoop_in.cyc and wb_snoop_in.stb and wb_snoop_in.we;
snoop_addr := (others => '0');
snoop_addr(wb_snoop_in.adr'left + ROW_OFF_BITS downto ROW_OFF_BITS) := wb_snoop_in.adr;
snoop_addr := addr_to_real(wb_to_addr(wb_snoop_in.adr));
snoop_index <= get_index(snoop_addr);
snoop_cache_tags := cache_tags(get_index(snoop_addr));
snoop_tag := get_tag(snoop_addr, '0');
@ -709,15 +704,15 @@ begin

-- Keep track of our index and way for subsequent stores
r.store_index <= req_index;
r.store_row <= get_row(req_laddr);
r.store_row <= get_row(req_raddr);
r.store_tag <= req_tag;
r.store_valid <= '1';
r.end_row_ix <= get_row_of_line(get_row(req_laddr)) - 1;
r.end_row_ix <= get_row_of_line(get_row(req_raddr)) - 1;

-- Prep for first wishbone read. We calculate the address of
-- the start of the cache line and start the WB cycle.
--
r.wb.adr <= req_laddr(r.wb.adr'left + ROW_OFF_BITS downto ROW_OFF_BITS);
r.wb.adr <= addr_to_wb(req_raddr);
r.wb.cyc <= '1';
r.wb.stb <= '1';

@ -749,12 +744,12 @@ begin
if wishbone_in.stall = '0' and r.wb.stb = '1' then
-- That was the last word ? We are done sending. Clear stb.
--
if is_last_row_addr(r.wb.adr, r.end_row_ix) then
if is_last_row_wb_addr(r.wb.adr, r.end_row_ix) then
r.wb.stb <= '0';
end if;

-- Calculate the next row address
r.wb.adr <= next_row_addr(r.wb.adr);
r.wb.adr <= next_row_wb_addr(r.wb.adr);
end if;

-- Abort reload if we get an invalidation
@ -785,7 +780,7 @@ begin
when STOP_RELOAD =>
-- Wait for all outstanding requests to be satisfied, then
-- go to IDLE state.
if get_row_of_line(r.store_row) = get_row_of_line(get_row(r.wb.adr)) then
if get_row_of_line(r.store_row) = get_row_of_line(get_row(wb_to_addr(r.wb.adr))) then
r.wb.cyc <= '0';
r.state <= IDLE;
end if;

20
wishbone_types.vhdl
Unescape Escape View File

@ -15,6 +15,9 @@ package wishbone_types is
subtype wishbone_data_type is std_ulogic_vector(wishbone_data_bits-1 downto 0);
subtype wishbone_sel_type is std_ulogic_vector(wishbone_sel_bits-1 downto 0);

function addr_to_wb(addr: std_ulogic_vector) return wishbone_addr_type;
function wb_to_addr(wb_addr: wishbone_addr_type) return std_ulogic_vector;

type wishbone_master_out is record
adr : wishbone_addr_type;
dat : wishbone_data_type;
@ -38,6 +41,7 @@ package wishbone_types is
--
-- IO Bus to a device, 30-bit address, 32-bits data
--

type wb_io_master_out is record
adr : std_ulogic_vector(29 downto 0);
dat : std_ulogic_vector(31 downto 0);
@ -56,3 +60,19 @@ package wishbone_types is
end record;
constant wb_io_slave_out_init : wb_io_slave_out := (ack => '0', stall => '0', others => (others => '0'));
end package wishbone_types;

package body wishbone_types is
function addr_to_wb(addr: std_ulogic_vector) return wishbone_addr_type is
begin
assert addr'length >= (wishbone_addr_type'length + wishbone_log2_width);
assert addr'right = 0;
return addr(wishbone_addr_type'left + wishbone_log2_width downto wishbone_log2_width);
end;
function wb_to_addr(wb_addr: wishbone_addr_type) return std_ulogic_vector is
variable ret : std_ulogic_vector(63 downto 0);
begin
ret := (others => '0');
ret(wishbone_addr_type'left + wishbone_log2_width downto wishbone_log2_width) := wb_addr;
return ret;
end;
end wishbone_types;

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