-"""Dcache
+"""DCache
based on Anton Blanchard microwatt dcache.vhdl
from enum import Enum, unique
-from nmigen import Module, Signal, Elaboratable,
- Cat, Repl
-from nmigen.cli import main
-from nmigen.iocontrol import RecordObject
-from nmigen.util import log2_int
+from nmigen import Module, Signal, Elaboratable, Cat, Repl, Array, Const
+from nmutil.util import Display
-from experiment.mem_types import LoadStore1ToDcacheType,
- DcacheToLoadStore1Type,
- MmuToDcacheType,
- DcacheToMmuType
+from random import randint
-from experiment.wb_types import WB_ADDR_BITS, WB_DATA_BITS, WB_SEL_BITS,
+from nmigen.cli import main
+from nmutil.iocontrol import RecordObject
+from nmigen.utils import log2_int
+from soc.experiment.mem_types import (LoadStore1ToDCacheType,
+ DCacheToLoadStore1Type,
+ MMUToDCacheType,
+ DCacheToMMUType)
+
+from soc.experiment.wb_types import (WB_ADDR_BITS, WB_DATA_BITS, WB_SEL_BITS,
WBAddrType, WBDataType, WBSelType,
- WbMasterOut, WBSlaveOut,
+ WBMasterOut, WBSlaveOut,
WBMasterOutVector, WBSlaveOutVector,
- WBIOMasterOut, WBIOSlaveOut
+ WBIOMasterOut, WBIOSlaveOut)
+
+from soc.experiment.cache_ram import CacheRam
+#from soc.experiment.plru import PLRU
+from nmutil.plru import PLRU
+
+# for test
+from nmigen_soc.wishbone.sram import SRAM
+from nmigen import Memory
+from nmigen.cli import rtlil
+
+# NOTE: to use cxxsim, export NMIGEN_SIM_MODE=cxxsim from the shell
+# Also, check out the cxxsim nmigen branch, and latest yosys from git
+from nmutil.sim_tmp_alternative import Simulator
+
+from nmutil.util import wrap
+
+
+# TODO: make these parameters of DCache at some point
+LINE_SIZE = 64 # Line size in bytes
+NUM_LINES = 16 # Number of lines in a set
+NUM_WAYS = 4 # Number of ways
+TLB_SET_SIZE = 64 # L1 DTLB entries per set
+TLB_NUM_WAYS = 4 # L1 DTLB number of sets
+TLB_LG_PGSZ = 12 # L1 DTLB log_2(page_size)
+LOG_LENGTH = 0 # Non-zero to enable log data collection
+
+# BRAM organisation: We never access more than
+# -- WB_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 WB, so 64-bits)
+ROW_SIZE = WB_DATA_BITS // 8;
+
+# ROW_PER_LINE is the number of row (wishbone
+# transactions) in a line
+ROW_PER_LINE = LINE_SIZE // ROW_SIZE
+
+# BRAM_ROWS is the number of rows in BRAM needed
+# to represent the full dcache
+BRAM_ROWS = NUM_LINES * ROW_PER_LINE
+
+print ("ROW_SIZE", ROW_SIZE)
+print ("ROW_PER_LINE", ROW_PER_LINE)
+print ("BRAM_ROWS", BRAM_ROWS)
+print ("NUM_WAYS", NUM_WAYS)
+
+# Bit fields counts in the address
+
+# REAL_ADDR_BITS is the number of real address
+# bits that we store
+REAL_ADDR_BITS = 56
+
+# ROW_BITS is the number of bits to select a row
+ROW_BITS = log2_int(BRAM_ROWS)
+
+# ROW_LINE_BITS is the number of bits to select
+# a row within a line
+ROW_LINE_BITS = log2_int(ROW_PER_LINE)
+
+# LINE_OFF_BITS is the number of bits for
+# the offset in a cache line
+LINE_OFF_BITS = log2_int(LINE_SIZE)
+
+# ROW_OFF_BITS is the number of bits for
+# the offset in a row
+ROW_OFF_BITS = log2_int(ROW_SIZE)
+
+# INDEX_BITS is the number if bits to
+# select a cache line
+INDEX_BITS = log2_int(NUM_LINES)
+
+# SET_SIZE_BITS is the log base 2 of the set size
+SET_SIZE_BITS = LINE_OFF_BITS + INDEX_BITS
+
+# TAG_BITS is the number of bits of
+# the tag part of the address
+TAG_BITS = REAL_ADDR_BITS - SET_SIZE_BITS
+
+# TAG_WIDTH is the width in bits of each way of the tag RAM
+TAG_WIDTH = TAG_BITS + 7 - ((TAG_BITS + 7) % 8)
+
+# WAY_BITS is the number of bits to select a way
+WAY_BITS = log2_int(NUM_WAYS)
+
+# Example of layout for 32 lines of 64 bytes:
+layout = """\
+ .. tag |index| line |
+ .. | row | |
+ .. | |---| | ROW_LINE_BITS (3)
+ .. | |--- - --| LINE_OFF_BITS (6)
+ .. | |- --| ROW_OFF_BITS (3)
+ .. |----- ---| | ROW_BITS (8)
+ .. |-----| | INDEX_BITS (5)
+ .. --------| | TAG_BITS (45)
+"""
+print (layout)
+print ("Dcache TAG %d IDX %d ROW_BITS %d ROFF %d LOFF %d RLB %d" % \
+ (TAG_BITS, INDEX_BITS, ROW_BITS,
+ ROW_OFF_BITS, LINE_OFF_BITS, ROW_LINE_BITS))
+print ("index @: %d-%d" % (LINE_OFF_BITS, SET_SIZE_BITS))
+print ("row @: %d-%d" % (LINE_OFF_BITS, ROW_OFF_BITS))
+print ("tag @: %d-%d width %d" % (SET_SIZE_BITS, REAL_ADDR_BITS, TAG_WIDTH))
+
+TAG_RAM_WIDTH = TAG_WIDTH * NUM_WAYS
+
+print ("TAG_RAM_WIDTH", TAG_RAM_WIDTH)
+
+def CacheTagArray():
+ return Array(Signal(TAG_RAM_WIDTH, name="cachetag_%d" % x) \
+ for x in range(NUM_LINES))
+
+def CacheValidBitsArray():
+ return Array(Signal(NUM_WAYS, name="cachevalid_%d" % x) \
+ for x in range(NUM_LINES))
+
+def RowPerLineValidArray():
+ return Array(Signal(name="rows_valid%d" % x) \
+ for x in range(ROW_PER_LINE))
+
+# L1 TLB
+TLB_SET_BITS = log2_int(TLB_SET_SIZE)
+TLB_WAY_BITS = log2_int(TLB_NUM_WAYS)
+TLB_EA_TAG_BITS = 64 - (TLB_LG_PGSZ + TLB_SET_BITS)
+TLB_TAG_WAY_BITS = TLB_NUM_WAYS * TLB_EA_TAG_BITS
+TLB_PTE_BITS = 64
+TLB_PTE_WAY_BITS = TLB_NUM_WAYS * TLB_PTE_BITS;
+
+def ispow2(x):
+ return (1<<log2_int(x, False)) == x
+
+assert (LINE_SIZE % ROW_SIZE) == 0, "LINE_SIZE not multiple of ROW_SIZE"
+assert ispow2(LINE_SIZE), "LINE_SIZE not power of 2"
+assert ispow2(NUM_LINES), "NUM_LINES not power of 2"
+assert ispow2(ROW_PER_LINE), "ROW_PER_LINE not power of 2"
+assert ROW_BITS == (INDEX_BITS + ROW_LINE_BITS), "geometry bits don't add up"
+assert (LINE_OFF_BITS == ROW_OFF_BITS + ROW_LINE_BITS), \
+ "geometry bits don't add up"
+assert REAL_ADDR_BITS == (TAG_BITS + INDEX_BITS + LINE_OFF_BITS), \
+ "geometry bits don't add up"
+assert REAL_ADDR_BITS == (TAG_BITS + ROW_BITS + ROW_OFF_BITS), \
+ "geometry bits don't add up"
+assert 64 == WB_DATA_BITS, "Can't yet handle wb width that isn't 64-bits"
+assert SET_SIZE_BITS <= TLB_LG_PGSZ, "Set indexed by virtual address"
+
+
+def TLBValidBitsArray():
+ return Array(Signal(TLB_NUM_WAYS, name="tlbvalid%d" % x) \
+ for x in range(TLB_SET_SIZE))
+
+def TLBTagEAArray():
+ return Array(Signal(TLB_EA_TAG_BITS, name="tlbtagea%d" % x) \
+ for x in range (TLB_NUM_WAYS))
+
+def TLBTagsArray():
+ return Array(Signal(TLB_TAG_WAY_BITS, name="tlbtags%d" % x) \
+ for x in range (TLB_SET_SIZE))
+
+def TLBPtesArray():
+ return Array(Signal(TLB_PTE_WAY_BITS, name="tlbptes%d" % x) \
+ for x in range(TLB_SET_SIZE))
+
+def HitWaySet():
+ return Array(Signal(WAY_BITS, name="hitway_%d" % x) \
+ for x in range(TLB_NUM_WAYS))
+
+# Cache RAM interface
+def CacheRamOut():
+ return Array(Signal(WB_DATA_BITS, name="cache_out%d" % x) \
+ for x in range(NUM_WAYS))
+
+# PLRU output interface
+def PLRUOut():
+ return Array(Signal(WAY_BITS, name="plru_out%d" % x) \
+ for x in range(NUM_LINES))
+
+# TLB PLRU output interface
+def TLBPLRUOut():
+ return Array(Signal(TLB_WAY_BITS, name="tlbplru_out%d" % x) \
+ for x in range(TLB_SET_SIZE))
+
+# Helper functions to decode incoming requests
+#
+# Return the cache line index (tag index) for an address
+def get_index(addr):
+ return addr[LINE_OFF_BITS:SET_SIZE_BITS]
+
+# Return the cache row index (data memory) for an address
+def get_row(addr):
+ return addr[ROW_OFF_BITS:SET_SIZE_BITS]
+
+# Return the index of a row within a line
+def get_row_of_line(row):
+ return row[:ROW_BITS][:ROW_LINE_BITS]
+
+# Returns whether this is the last row of a line
+def is_last_row_addr(addr, last):
+ return addr[ROW_OFF_BITS:LINE_OFF_BITS] == last
+
+# Returns whether this is the last row of a line
+def is_last_row(row, last):
+ return get_row_of_line(row) == last
+
+# Return the next row in the current cache line. We use a
+# dedicated function in order to limit the size of the
+# generated adder to be only the bits within a cache line
+# (3 bits with default settings)
+def next_row(row):
+ row_v = row[0:ROW_LINE_BITS] + 1
+ return Cat(row_v[:ROW_LINE_BITS], row[ROW_LINE_BITS:])
+
+# Get the tag value from the address
+def get_tag(addr):
+ return addr[SET_SIZE_BITS:REAL_ADDR_BITS]
+
+# Read a tag from a tag memory row
+def read_tag(way, tagset):
+ return tagset.word_select(way, TAG_WIDTH)[:TAG_BITS]
+
+# Read a TLB tag from a TLB tag memory row
+def read_tlb_tag(way, tags):
+ return tags.word_select(way, TLB_EA_TAG_BITS)
+
+# Write a TLB tag to a TLB tag memory row
+def write_tlb_tag(way, tags, tag):
+ return read_tlb_tag(way, tags).eq(tag)
+
+# Read a PTE from a TLB PTE memory row
+def read_tlb_pte(way, ptes):
+ return ptes.word_select(way, TLB_PTE_BITS)
+
+def write_tlb_pte(way, ptes, newpte):
+ return read_tlb_pte(way, ptes).eq(newpte)
# Record for storing permission, attribute, etc. bits from a PTE
class PermAttr(RecordObject):
- def __init__(self):
- super().__init__()
+ def __init__(self, name=None):
+ super().__init__(name=name)
self.reference = Signal()
self.changed = Signal()
self.nocache = Signal()
def extract_perm_attr(pte):
pa = PermAttr()
- pa.reference = pte[8]
- pa.changed = pte[7]
- pa.nocache = pte[5]
- pa.priv = pte[3]
- pa.rd_perm = pte[2]
- pa.wr_perm = pte[1]
return pa;
# time as the first stage emits a stall for a complex op.
#
# Stage 0 register, basically contains just the latched request
+
class RegStage0(RecordObject):
- def __init__(self):
- super().__init__()
- self.req = LoadStore1ToDcacheType()
+ def __init__(self, name=None):
+ super().__init__(name=name)
+ self.req = LoadStore1ToDCacheType(name="lsmem")
self.tlbie = Signal()
self.doall = Signal()
self.tlbld = Signal()
class MemAccessRequest(RecordObject):
- def __init__(self):
- super().__init__()
- self.op = Op()
+ def __init__(self, name=None):
+ super().__init__(name=name)
+ self.op = Signal(Op)
self.valid = Signal()
self.dcbz = Signal()
self.real_addr = Signal(REAL_ADDR_BITS)
# First stage register, contains state for stage 1 of load hits
# and for the state machine used by all other operations
class RegStage1(RecordObject):
- def __init__(self):
- super().__init__()
+ def __init__(self, name=None):
+ super().__init__(name=name)
# Info about the request
self.full = Signal() # have uncompleted request
self.mmu_req = Signal() # request is from MMU
- self.req = MemAccessRequest()
+ self.req = MemAccessRequest(name="reqmem")
# Cache hit state
self.hit_way = Signal(WAY_BITS)
self.hit_load_valid = Signal()
- self.hit_index = Signal(NUM_LINES)
+ self.hit_index = Signal(INDEX_BITS)
self.cache_hit = Signal()
# TLB hit state
self.tlb_hit = Signal()
self.tlb_hit_way = Signal(TLB_NUM_WAYS)
- self.tlb_hit_index = Signal(TLB_SET_SIZE)
- self.
+ self.tlb_hit_index = Signal(TLB_WAY_BITS)
+
# 2-stage data buffer for data forwarded from writes to reads
self.forward_data1 = Signal(64)
self.forward_data2 = Signal(64)
self.forward_sel1 = Signal(8)
self.forward_valid1 = Signal()
self.forward_way1 = Signal(WAY_BITS)
- self.forward_row1 = Signal(BRAM_ROWS)
+ self.forward_row1 = Signal(ROW_BITS)
self.use_forward1 = Signal()
self.forward_sel = Signal(8)
# Cache miss state (reload state machine)
- self.state = State()
+ self.state = Signal(State)
self.dcbz = Signal()
self.write_bram = Signal()
self.write_tag = Signal()
self.slow_valid = Signal()
- self.wb = WishboneMasterOut()
+ self.real_adr = Signal(REAL_ADDR_BITS)
+ self.wb = WBMasterOut("wb")
self.reload_tag = Signal(TAG_BITS)
self.store_way = Signal(WAY_BITS)
- self.store_row = Signal(BRAM_ROWS)
- self.store_index = Signal(NUM_LINES)
- self.end_row_ix = Signal(ROW_LINE_BIT)
+ self.store_row = Signal(ROW_BITS)
+ self.store_index = Signal(INDEX_BITS)
+ self.end_row_ix = Signal(ROW_LINE_BITS)
self.rows_valid = RowPerLineValidArray()
self.acks_pending = Signal(3)
self.inc_acks = Signal()
class Reservation(RecordObject):
def __init__(self):
super().__init__()
- valid = Signal()
- # TODO LINE_OFF_BITS is 6
- addr = Signal(63 downto LINE_OFF_BITS)
+ self.valid = Signal()
+ self.addr = Signal(64-LINE_OFF_BITS)
-# Set associative dcache write-through
-#
-# TODO (in no specific order):
-#
-# * See list in icache.vhdl
-# * Complete load misses on the cycle when WB data comes instead of
-# at the end of line (this requires dealing with requests coming in
-# while not idle...)
-class Dcache(Elaboratable):
+class DTLBUpdate(Elaboratable):
def __init__(self):
- # TODO: make these parameters of Dcache at some point
- self.LINE_SIZE = 64 # Line size in bytes
- self.NUM_LINES = 32 # Number of lines in a set
- self.NUM_WAYS = 4 # Number of ways
- self.TLB_SET_SIZE = 64 # L1 DTLB entries per set
- self.TLB_NUM_WAYS = 2 # L1 DTLB number of sets
- self.TLB_LG_PGSZ = 12 # L1 DTLB log_2(page_size)
- self.LOG_LENGTH = 0 # Non-zero to enable log data collection
+ self.tlbie = Signal()
+ self.tlbwe = Signal()
+ self.doall = Signal()
+ self.updated = Signal()
+ self.v_updated = Signal()
+ self.tlb_hit = Signal()
+ self.tlb_req_index = Signal(TLB_SET_BITS)
+
+ self.tlb_hit_way = Signal(TLB_WAY_BITS)
+ self.tlb_tag_way = Signal(TLB_TAG_WAY_BITS)
+ self.tlb_pte_way = Signal(TLB_PTE_WAY_BITS)
+ self.repl_way = Signal(TLB_WAY_BITS)
+ self.eatag = Signal(TLB_EA_TAG_BITS)
+ self.pte_data = Signal(TLB_PTE_BITS)
+
+ self.dv = Signal(TLB_PTE_WAY_BITS)
+
+ self.tb_out = Signal(TLB_TAG_WAY_BITS)
+ self.pb_out = Signal(TLB_NUM_WAYS)
+ self.db_out = Signal(TLB_PTE_WAY_BITS)
+
+ def elaborate(self, platform):
+ m = Module()
+ comb = m.d.comb
+ sync = m.d.sync
- self.d_in = LoadStore1ToDcacheType()
- self.d_out = DcacheToLoadStore1Type()
+ tagset = Signal(TLB_TAG_WAY_BITS)
+ pteset = Signal(TLB_PTE_WAY_BITS)
- self.m_in = MmuToDcacheType()
- self.m_out = DcacheToMmuType()
+ tb_out, pb_out, db_out = self.tb_out, self.pb_out, self.db_out
+
+ with m.If(self.tlbie & self.doall):
+ pass # clear all back in parent
+ with m.Elif(self.tlbie):
+ with m.If(self.tlb_hit):
+ comb += db_out.eq(self.dv)
+ comb += db_out.bit_select(self.tlb_hit_way, 1).eq(1)
+ comb += self.v_updated.eq(1)
+
+ with m.Elif(self.tlbwe):
+
+ comb += tagset.eq(self.tlb_tag_way)
+ comb += write_tlb_tag(self.repl_way, tagset, self.eatag)
+ comb += tb_out.eq(tagset)
+
+ comb += pteset.eq(self.tlb_pte_way)
+ comb += write_tlb_pte(self.repl_way, pteset, self.pte_data)
+ comb += pb_out.eq(pteset)
+
+ comb += db_out.bit_select(self.repl_way, 1).eq(1)
+
+ comb += self.updated.eq(1)
+ comb += self.v_updated.eq(1)
+
+ return m
+
+
+class DCachePendingHit(Elaboratable):
+
+ def __init__(self, tlb_pte_way, tlb_valid_way, tlb_hit_way,
+ cache_valid_idx, cache_tag_set,
+ req_addr,
+ hit_set):
+
+ self.go = Signal()
+ self.virt_mode = Signal()
+ self.is_hit = Signal()
+ self.tlb_hit = Signal()
+ self.hit_way = Signal(WAY_BITS)
+ self.rel_match = Signal()
+ self.req_index = Signal(INDEX_BITS)
+ self.reload_tag = Signal(TAG_BITS)
+
+ self.tlb_hit_way = tlb_hit_way
+ self.tlb_pte_way = tlb_pte_way
+ self.tlb_valid_way = tlb_valid_way
+ self.cache_valid_idx = cache_valid_idx
+ self.cache_tag_set = cache_tag_set
+ self.req_addr = req_addr
+ self.hit_set = hit_set
+
+ def elaborate(self, platform):
+ m = Module()
+ comb = m.d.comb
+ sync = m.d.sync
+
+ go = self.go
+ virt_mode = self.virt_mode
+ is_hit = self.is_hit
+ tlb_pte_way = self.tlb_pte_way
+ tlb_valid_way = self.tlb_valid_way
+ cache_valid_idx = self.cache_valid_idx
+ cache_tag_set = self.cache_tag_set
+ req_addr = self.req_addr
+ tlb_hit_way = self.tlb_hit_way
+ tlb_hit = self.tlb_hit
+ hit_set = self.hit_set
+ hit_way = self.hit_way
+ rel_match = self.rel_match
+ req_index = self.req_index
+ reload_tag = self.reload_tag
+
+ rel_matches = Array(Signal(name="rel_matches_%d" % i) \
+ for i in range(TLB_NUM_WAYS))
+ hit_way_set = HitWaySet()
+
+ # Test if pending request is a hit on any way
+ # In order to make timing in virtual mode,
+ # when we are using the TLB, we compare each
+ # way with each of the real addresses from each way of
+ # the TLB, and then decide later which match to use.
+
+ with m.If(virt_mode):
+ for j in range(TLB_NUM_WAYS):
+ s_tag = Signal(TAG_BITS, name="s_tag%d" % j)
+ s_hit = Signal()
+ s_pte = Signal(TLB_PTE_BITS)
+ s_ra = Signal(REAL_ADDR_BITS)
+ comb += s_pte.eq(read_tlb_pte(j, tlb_pte_way))
+ comb += s_ra.eq(Cat(req_addr[0:TLB_LG_PGSZ],
+ s_pte[TLB_LG_PGSZ:REAL_ADDR_BITS]))
+ comb += s_tag.eq(get_tag(s_ra))
+
+ for i in range(NUM_WAYS):
+ is_tag_hit = Signal(name="is_tag_hit_%d_%d" % (j, i))
+ comb += is_tag_hit.eq(go & cache_valid_idx[i] &
+ (read_tag(i, cache_tag_set) == s_tag)
+ & tlb_valid_way[j])
+ with m.If(is_tag_hit):
+ comb += hit_way_set[j].eq(i)
+ comb += s_hit.eq(1)
+ comb += hit_set[j].eq(s_hit)
+ with m.If(s_tag == reload_tag):
+ comb += rel_matches[j].eq(1)
+ with m.If(tlb_hit):
+ comb += is_hit.eq(hit_set[tlb_hit_way])
+ comb += hit_way.eq(hit_way_set[tlb_hit_way])
+ comb += rel_match.eq(rel_matches[tlb_hit_way])
+ with m.Else():
+ s_tag = Signal(TAG_BITS)
+ comb += s_tag.eq(get_tag(req_addr))
+ for i in range(NUM_WAYS):
+ is_tag_hit = Signal(name="is_tag_hit_%d" % i)
+ comb += is_tag_hit.eq(go & cache_valid_idx[i] &
+ (read_tag(i, cache_tag_set) == s_tag))
+ with m.If(is_tag_hit):
+ comb += hit_way.eq(i)
+ comb += is_hit.eq(1)
+ with m.If(s_tag == reload_tag):
+ comb += rel_match.eq(1)
+
+ return m
+
+
+class DCache(Elaboratable):
+ """Set associative dcache write-through
+ TODO (in no specific order):
+ * See list in icache.vhdl
+ * Complete load misses on the cycle when WB data comes instead of
+ at the end of line (this requires dealing with requests coming in
+ while not idle...)
+ """
+ def __init__(self):
+ self.d_in = LoadStore1ToDCacheType("d_in")
+ self.d_out = DCacheToLoadStore1Type("d_out")
+
+ self.m_in = MMUToDCacheType("m_in")
+ self.m_out = DCacheToMMUType("m_out")
self.stall_out = Signal()
self.log_out = Signal(20)
- # Latch the request in r0.req as long as we're not stalling
- def stage_0(self, m, d_in, m_in):
- comb = m.d.comb
- sync = m.d.sync
+ def stage_0(self, m, r0, r1, r0_full):
+ """Latch the request in r0.req as long as we're not stalling
+ """
+ comb = m.d.comb
+ sync = m.d.sync
+ d_in, d_out, m_in = self.d_in, self.d_out, self.m_in
- # variable r : reg_stage_0_t;
- r = RegStage0()
- comb += r
+ r = RegStage0("stage0")
- # begin
- # if rising_edge(clk) then
- # assert (d_in.valid and m_in.valid) = '0'
- # report "request collision loadstore vs MMU";
- assert ~(d_in.valid & m_in.valid) "request collision
- loadstore vs MMU"
+ # TODO, this goes in unit tests and formal proofs
+ with m.If(d_in.valid & m_in.valid):
+ sync += Display("request collision loadstore vs MMU")
- # if m_in.valid = '1' then
- with m.If(m_in.valid):
- # r.req.valid := '1';
- # r.req.load := not (m_in.tlbie or m_in.tlbld);
- # r.req.dcbz := '0';
- # r.req.nc := '0';
- # r.req.reserve := '0';
- # r.req.virt_mode := '0';
- # r.req.priv_mode := '1';
- # r.req.addr := m_in.addr;
- # r.req.data := m_in.pte;
- # r.req.byte_sel := (others => '1');
- # r.tlbie := m_in.tlbie;
- # r.doall := m_in.doall;
- # r.tlbld := m_in.tlbld;
- # r.mmu_req := '1';
- sync += r.req.valid.eq(1)
- sync += r.req.load.eq(~(m_in.tlbie | m_in.tlbld))
- sync += r.req.priv_mode.eq(1)
- sync += r.req.addr.eq(m_in.addr)
- sync += r.req.data.eq(m_in.pte)
- sync += r.req.byte_sel.eq(1)
- sync += r.tlbie.eq(m_in.tlbie)
- sync += r.doall.eq(m_in.doall)
- sync += r.tlbld.eq(m_in.tlbld)
- sync += r.mmu_req.eq(1)
- # else
- with m.Else():
- # r.req := d_in;
- # r.tlbie := '0';
- # r.doall := '0';
- # r.tlbld := '0';
- # r.mmu_req := '0';
- sync += r.req.eq(d_in)
- # end if;
- # if rst = '1' then
- # r0_full <= '0';
- # elsif r1.full = '0' or r0_full = '0' then
- with m.If(~r1.full | ~r0_full):
- # r0 <= r;
- # r0_full <= r.req.valid;
- sync += r0.eq(r)
- sync += r0_full.eq(r.req.valid)
- # end if;
- # end if;
- # end process;
-
- # TLB
- # Operates in the second cycle on the request latched in r0.req.
- # TLB updates write the entry at the end of the second cycle.
- def tlb_read(self, m, m_in, d_in, r0_stall, tlb_valid_way,
+ with m.If(m_in.valid):
+ sync += r.req.valid.eq(1)
+ sync += r.req.load.eq(~(m_in.tlbie | m_in.tlbld))
+ sync += r.req.dcbz.eq(0)
+ sync += r.req.nc.eq(0)
+ sync += r.req.reserve.eq(0)
+ sync += r.req.virt_mode.eq(0)
+ sync += r.req.priv_mode.eq(1)
+ sync += r.req.addr.eq(m_in.addr)
+ sync += r.req.data.eq(m_in.pte)
+ sync += r.req.byte_sel.eq(~0) # Const -1 sets all to 0b111....
+ sync += r.tlbie.eq(m_in.tlbie)
+ sync += r.doall.eq(m_in.doall)
+ sync += r.tlbld.eq(m_in.tlbld)
+ sync += r.mmu_req.eq(1)
+ with m.Else():
+ sync += r.req.eq(d_in)
+ sync += r.tlbie.eq(0)
+ sync += r.doall.eq(0)
+ sync += r.tlbld.eq(0)
+ sync += r.mmu_req.eq(0)
+ with m.If(~(r1.full & r0_full)):
+ sync += r0.eq(r)
+ sync += r0_full.eq(r.req.valid)
+
+ def tlb_read(self, m, r0_stall, tlb_valid_way,
tlb_tag_way, tlb_pte_way, dtlb_valid_bits,
dtlb_tags, dtlb_ptes):
-
+ """TLB
+ Operates in the second cycle on the request latched in r0.req.
+ TLB updates write the entry at the end of the second cycle.
+ """
comb = m.d.comb
sync = m.d.sync
+ m_in, d_in = self.m_in, self.d_in
- # variable index : tlb_index_t;
- # variable addrbits :
- # std_ulogic_vector(TLB_SET_BITS - 1 downto 0);
- index = TLB_SET_SIZE
+ index = Signal(TLB_SET_BITS)
addrbits = Signal(TLB_SET_BITS)
- comb += index
- comb += addrbits
+ amin = TLB_LG_PGSZ
+ amax = TLB_LG_PGSZ + TLB_SET_BITS
- # begin
- # if rising_edge(clk) then
- # if m_in.valid = '1' then
with m.If(m_in.valid):
- # addrbits := m_in.addr(TLB_LG_PGSZ + TLB_SET_BITS
- # - 1 downto TLB_LG_PGSZ);
- sync += addrbits.eq(m_in.addr[
- TLB_LG_PGSZ:TLB_LG_PGSZ + TLB_SET_BITS
- ])
- # else
+ comb += addrbits.eq(m_in.addr[amin : amax])
with m.Else():
- # addrbits := d_in.addr(TLB_LG_PGSZ + TLB_SET_BITS
- # - 1 downto TLB_LG_PGSZ);
- sync += addrbits.eq(d_in.addr[
- TLB_LG_PGSZ:TLB_LG_PGSZ + TLB_SET_BITS
- ])
- # end if;
-
- # index := to_integer(unsigned(addrbits));
- sync += index.eq(addrbits)
- # -- If we have any op and the previous op isn't
- # -- finished, then keep the same output for next cycle.
- # if r0_stall = '0' then
- # If we have any op and the previous op isn't finished,
- # then keep the same output for next cycle.
+ comb += addrbits.eq(d_in.addr[amin : amax])
+ comb += index.eq(addrbits)
+
+ # If we have any op and the previous op isn't finished,
+ # then keep the same output for next cycle.
with m.If(~r0_stall):
sync += tlb_valid_way.eq(dtlb_valid_bits[index])
sync += tlb_tag_way.eq(dtlb_tags[index])
sync += tlb_pte_way.eq(dtlb_ptes[index])
- # end if;
- # end if;
- # end process;
- # -- Generate TLB PLRUs
- # maybe_tlb_plrus: if TLB_NUM_WAYS > 1 generate
- # Generate TLB PLRUs
def maybe_tlb_plrus(self, m, r1, tlb_plru_victim):
- comb = m.d.comb
- sync = m.d.sync
-
- with m.If(TLB_NUM_WAYS > 1):
- # begin
- # TODO understand how to conver generate statements
- # tlb_plrus: for i in 0 to TLB_SET_SIZE - 1 generate
- # -- TLB PLRU interface
- # signal tlb_plru_acc :
- # std_ulogic_vector(TLB_WAY_BITS-1 downto 0);
- # signal tlb_plru_acc_en : std_ulogic;
- # signal tlb_plru_out :
- # std_ulogic_vector(TLB_WAY_BITS-1 downto 0);
- # begin
- # tlb_plru : entity work.plru
- # generic map (
- # BITS => TLB_WAY_BITS
- # )
- # port map (
- # clk => clk,
- # rst => rst,
- # acc => tlb_plru_acc,
- # acc_en => tlb_plru_acc_en,
- # lru => tlb_plru_out
- # );
- #
- # process(all)
- # begin
- # -- PLRU interface
- # if r1.tlb_hit_index = i then
- # tlb_plru_acc_en <= r1.tlb_hit;
- # else
- # tlb_plru_acc_en <= '0';
- # end if;
- # tlb_plru_acc <=
- # std_ulogic_vector(to_unsigned(
- # r1.tlb_hit_way, TLB_WAY_BITS
- # ));
- # tlb_plru_victim(i) <= tlb_plru_out;
- # end process;
- # end generate;
- # end generate;
- # end TODO
-
- def tlb_search(self, tlb_req_index, r0, tlb_valid_way_ tlb_tag_way,
+ """Generate TLB PLRUs
+ """
+ comb = m.d.comb
+ sync = m.d.sync
+
+ if TLB_NUM_WAYS == 0:
+ return
+ for i in range(TLB_SET_SIZE):
+ # TLB PLRU interface
+ tlb_plru = PLRU(TLB_WAY_BITS)
+ setattr(m.submodules, "maybe_plru_%d" % i, tlb_plru)
+ tlb_plru_acc_en = Signal()
+
+ comb += tlb_plru_acc_en.eq(r1.tlb_hit & (r1.tlb_hit_index == i))
+ comb += tlb_plru.acc_en.eq(tlb_plru_acc_en)
+ comb += tlb_plru.acc_i.eq(r1.tlb_hit_way)
+ comb += tlb_plru_victim[i].eq(tlb_plru.lru_o)
+
+ def tlb_search(self, m, tlb_req_index, r0, r0_valid,
+ tlb_valid_way, tlb_tag_way, tlb_hit_way,
tlb_pte_way, pte, tlb_hit, valid_ra, perm_attr, ra):
comb = m.d.comb
sync = m.d.sync
-# variable hitway : tlb_way_t;
-# variable hit : std_ulogic;
-# variable eatag : tlb_tag_t;
- hitway = TLBWay()
+ hitway = Signal(TLB_WAY_BITS)
hit = Signal()
- eatag = TLBTag()
-
- comb += hitway
- comb += hit
- comb += eatag
-
-# begin
-# tlb_req_index <=
-# to_integer(unsigned(r0.req.addr(
-# TLB_LG_PGSZ + TLB_SET_BITS - 1 downto TLB_LG_PGSZ
-# )));
-# hitway := 0;
-# hit := '0';
-# eatag := r0.req.addr(63 downto TLB_LG_PGSZ + TLB_SET_BITS);
-# for i in tlb_way_t loop
-# if tlb_valid_way(i) = '1' and
-# read_tlb_tag(i, tlb_tag_way) = eatag then
-# hitway := i;
-# hit := '1';
-# end if;
-# end loop;
-# tlb_hit <= hit and r0_valid;
-# tlb_hit_way <= hitway;
- comb += tlb_req_index.eq(r0.req.addr[
- TLB_LG_PGSZ:TLB_LG_PGSZ + TLB_SET_BITS
- ])
-
- comb += eatag.eq(r0.req.addr[
- TLB_LG_PGSZ + TLB_SET_BITS:64
- ])
-
- for i in TLBWay():
- with m.If(tlb_valid_way(i)
- & read_tlb_tag(i, tlb_tag_way) == eatag):
+ eatag = Signal(TLB_EA_TAG_BITS)
+
+ TLB_LG_END = TLB_LG_PGSZ + TLB_SET_BITS
+ comb += tlb_req_index.eq(r0.req.addr[TLB_LG_PGSZ : TLB_LG_END])
+ comb += eatag.eq(r0.req.addr[TLB_LG_END : 64 ])
+ for i in range(TLB_NUM_WAYS):
+ is_tag_hit = Signal()
+ comb += is_tag_hit.eq(tlb_valid_way[i]
+ & (read_tlb_tag(i, tlb_tag_way) == eatag))
+ with m.If(is_tag_hit):
comb += hitway.eq(i)
comb += hit.eq(1)
comb += tlb_hit.eq(hit & r0_valid)
comb += tlb_hit_way.eq(hitway)
-# if tlb_hit = '1' then
with m.If(tlb_hit):
-# pte <= read_tlb_pte(hitway, tlb_pte_way);
comb += pte.eq(read_tlb_pte(hitway, tlb_pte_way))
-# else
with m.Else():
-# pte <= (others => '0');
comb += pte.eq(0)
-# end if;
-# valid_ra <= tlb_hit or not r0.req.virt_mode;
comb += valid_ra.eq(tlb_hit | ~r0.req.virt_mode)
-# if r0.req.virt_mode = '1' then
with m.If(r0.req.virt_mode):
-# ra <= pte(REAL_ADDR_BITS - 1 downto TLB_LG_PGSZ) &
-# r0.req.addr(TLB_LG_PGSZ - 1 downto ROW_OFF_BITS) &
-# (ROW_OFF_BITS-1 downto 0 => '0');
-# perm_attr <= extract_perm_attr(pte);
- comb += ra.eq(Cat(
- Const(ROW_OFF_BITS, ROW_OFF_BITS),
- r0.req.addr[ROW_OFF_BITS:TLB_LG_PGSZ],
- pte[TLB_LG_PGSZ:REAL_ADDR_BITS]
- ))
- comb += perm_attr.eq(extract_perm_attr(pte))
-# else
+ comb += ra.eq(Cat(Const(0, ROW_OFF_BITS),
+ r0.req.addr[ROW_OFF_BITS:TLB_LG_PGSZ],
+ pte[TLB_LG_PGSZ:REAL_ADDR_BITS]))
+ comb += perm_attr.reference.eq(pte[8])
+ comb += perm_attr.changed.eq(pte[7])
+ comb += perm_attr.nocache.eq(pte[5])
+ comb += perm_attr.priv.eq(pte[3])
+ comb += perm_attr.rd_perm.eq(pte[2])
+ comb += perm_attr.wr_perm.eq(pte[1])
with m.Else():
-# ra <= r0.req.addr(
-# REAL_ADDR_BITS - 1 downto ROW_OFF_BITS
-# ) & (ROW_OFF_BITS-1 downto 0 => '0');
- comb += ra.eq(Cat(
- Const(ROW_OFF_BITS, ROW_OFF_BITS),
- r0.rq.addr[ROW_OFF_BITS:REAL_ADDR_BITS]
- )
-
-# perm_attr <= real_mode_perm_attr;
+ comb += ra.eq(Cat(Const(0, ROW_OFF_BITS),
+ r0.req.addr[ROW_OFF_BITS:REAL_ADDR_BITS]))
+
comb += perm_attr.reference.eq(1)
comb += perm_attr.changed.eq(1)
- comb += perm_attr.priv.eq(1)
comb += perm_attr.nocache.eq(0)
+ comb += perm_attr.priv.eq(1)
comb += perm_attr.rd_perm.eq(1)
comb += perm_attr.wr_perm.eq(1)
-# end if;
-# end process;
- def tlb_update(self, r0_valid, r0, dtlb_valid_bits, tlb_req_index,
+ def tlb_update(self, m, r0_valid, r0, dtlb_valid_bits, tlb_req_index,
tlb_hit_way, tlb_hit, tlb_plru_victim, tlb_tag_way,
- dtlb_tags, tlb_pte_way, dtlb_ptes, dtlb_valid_bits):
+ dtlb_tags, tlb_pte_way, dtlb_ptes):
comb = m.d.comb
sync = m.d.sync
- # variable tlbie : std_ulogic;
- # variable tlbwe : std_ulogic;
- # variable repl_way : tlb_way_t;
- # variable eatag : tlb_tag_t;
- # variable tagset : tlb_way_tags_t;
- # variable pteset : tlb_way_ptes_t;
tlbie = Signal()
tlbwe = Signal()
- repl_way = TLBWay()
- eatag = TLBTag()
- tagset = TLBWayTags()
- pteset = TLBWayPtes()
-
- comb += tlbie
- comb += tlbwe
- comb += repl_way
- comb += eatag
- comb += tagset
- comb += pteset
-
- # begin
- # if rising_edge(clk) then
- # tlbie := r0_valid and r0.tlbie;
- # tlbwe := r0_valid and r0.tlbldoi;
- sync += tlbie.eq(r0_valid & r0.tlbie)
- sync += tlbwe.eq(r0_valid & r0.tlbldoi)
-
- # if rst = '1' or (tlbie = '1' and r0.doall = '1') then
- # with m.If (TODO understand how signal resets work in nmigen)
- # -- clear all valid bits at once
- # for i in tlb_index_t loop
- # dtlb_valids(i) <= (others => '0');
- # end loop;
+
+ comb += tlbie.eq(r0_valid & r0.tlbie)
+ comb += tlbwe.eq(r0_valid & r0.tlbld)
+
+ m.submodules.tlb_update = d = DTLBUpdate()
+ with m.If(tlbie & r0.doall):
# clear all valid bits at once
for i in range(TLB_SET_SIZE):
sync += dtlb_valid_bits[i].eq(0)
- # elsif tlbie = '1' then
- with m.Elif(tlbie):
- # if tlb_hit = '1' then
- with m.If(tlb_hit):
- # dtlb_valids(tlb_req_index)(tlb_hit_way) <= '0';
- sync += dtlb_valid_bits[tlb_req_index][tlb_hit_way].eq(0)
- # end if;
- # elsif tlbwe = '1' then
- with m.Elif(tlbwe):
- # if tlb_hit = '1' then
- with m.If(tlb_hit):
- # repl_way := tlb_hit_way;
- sync += repl_way.eq(tlb_hit_way)
- # else
- with m.Else():
- # repl_way := to_integer(unsigned(
- # tlb_plru_victim(tlb_req_index)));
- sync += repl_way.eq(tlb_plru_victim[tlb_req_index])
- # end if;
- # eatag := r0.req.addr(
- # 63 downto TLB_LG_PGSZ + TLB_SET_BITS
- # );
- # tagset := tlb_tag_way;
- # write_tlb_tag(repl_way, tagset, eatag);
- # dtlb_tags(tlb_req_index) <= tagset;
- # pteset := tlb_pte_way;
- # write_tlb_pte(repl_way, pteset, r0.req.data);
- # dtlb_ptes(tlb_req_index) <= pteset;
- # dtlb_valids(tlb_req_index)(repl_way) <= '1';
- sync += eatag.eq(r0.req.addr[TLB_LG_PGSZ + TLB_SET_BITS:64])
- sync += tagset.eq(tlb_tag_way)
- sync += write_tlb_tag(repl_way, tagset, eatag)
- sync += dtlb_tags[tlb_req_index].eq(tagset)
- sync += pteset.eq(tlb_pte_way)
- sync += write_tlb_pte(repl_way, pteset, r0.req.data)
- sync += dtlb_ptes[tlb_req_index].eq(pteset)
- sync += dtlb_valid_bits[tlb_req_index][repl_way].eq(1)
- # end if;
- # end if;
- # end process;
-
-# -- Generate PLRUs
-# maybe_plrus: if NUM_WAYS > 1 generate
- # Generate PLRUs
- def maybe_plrus(self, r1):
+ with m.If(d.updated):
+ sync += dtlb_tags[tlb_req_index].eq(d.tb_out)
+ sync += dtlb_ptes[tlb_req_index].eq(d.pb_out)
+ with m.If(d.v_updated):
+ sync += dtlb_valid_bits[tlb_req_index].eq(d.db_out)
+
+ comb += d.dv.eq(dtlb_valid_bits[tlb_req_index])
+
+ comb += d.tlbie.eq(tlbie)
+ comb += d.tlbwe.eq(tlbwe)
+ comb += d.doall.eq(r0.doall)
+ comb += d.tlb_hit.eq(tlb_hit)
+ comb += d.tlb_hit_way.eq(tlb_hit_way)
+ comb += d.tlb_tag_way.eq(tlb_tag_way)
+ comb += d.tlb_pte_way.eq(tlb_pte_way)
+ comb += d.tlb_req_index.eq(tlb_req_index)
+ with m.If(tlb_hit):
+ comb += d.repl_way.eq(tlb_hit_way)
+ with m.Else():
+ comb += d.repl_way.eq(tlb_plru_victim[tlb_req_index])
+ comb += d.eatag.eq(r0.req.addr[TLB_LG_PGSZ + TLB_SET_BITS:64])
+ comb += d.pte_data.eq(r0.req.data)
+
+ def maybe_plrus(self, m, r1, plru_victim):
+ """Generate PLRUs
+ """
comb = m.d.comb
sync = m.d.sync
-# begin
- # TODO learn translation of generate into nmgien @lkcl
-# plrus: for i in 0 to NUM_LINES-1 generate
-# -- PLRU interface
-# signal plru_acc : std_ulogic_vector(WAY_BITS-1 downto 0);
-# signal plru_acc_en : std_ulogic;
-# signal plru_out : std_ulogic_vector(WAY_BITS-1 downto 0);
-#
-# begin
- # TODO learn tranlation of entity, generic map, port map in
- # nmigen @lkcl
-# plru : entity work.plru
-# generic map (
-# BITS => WAY_BITS
-# )
-# port map (
-# clk => clk,
-# rst => rst,
-# acc => plru_acc,
-# acc_en => plru_acc_en,
-# lru => plru_out
-# );
-#
-# process(all)
-# begin
-# -- PLRU interface
-# if r1.hit_index = i then
- # PLRU interface
- with m.If(r1.hit_index == i):
-# plru_acc_en <= r1.cache_hit;
- comb += plru_acc_en.eq(r1.cache_hit)
-# else
- with m.Else():
-# plru_acc_en <= '0';
- comb += plru_acc_en.eq(0)
-# end if;
-# plru_acc <= std_ulogic_vector(to_unsigned(
-# r1.hit_way, WAY_BITS
-# ));
-# plru_victim(i) <= plru_out;
- comb += plru_acc.eq(r1.hit_way)
- comb += plru_victim[i].eq(plru_out)
-# end process;
-# end generate;
-# end generate;
-
-# -- Cache tag RAM read port
-# cache_tag_read : process(clk)
- # Cache tag RAM read port
- def cache_tag_read(self, r0_stall, req_index, m_in, d_in,
- cache_tag_set, cache_tags):
+ if TLB_NUM_WAYS == 0:
+ return
+
+ for i in range(NUM_LINES):
+ # PLRU interface
+ plru = PLRU(WAY_BITS)
+ setattr(m.submodules, "plru%d" % i, plru)
+ plru_acc_en = Signal()
+
+ comb += plru_acc_en.eq(r1.cache_hit & (r1.hit_index == i))
+ comb += plru.acc_en.eq(plru_acc_en)
+ comb += plru.acc_i.eq(r1.hit_way)
+ comb += plru_victim[i].eq(plru.lru_o)
+ def cache_tag_read(self, m, r0_stall, req_index, cache_tag_set, cache_tags):
+ """Cache tag RAM read port
+ """
comb = m.d.comb
sync = m.d.sync
+ m_in, d_in = self.m_in, self.d_in
-# variable index : index_t;
- index = Signal(NUM_LINES)
+ index = Signal(INDEX_BITS)
- comb += index
-
-# begin
-# if rising_edge(clk) then
-# if r0_stall = '1' then
with m.If(r0_stall):
-# index := req_index;
- sync += index.eq(req_index)
-
-# elsif m_in.valid = '1' then
+ comb += index.eq(req_index)
with m.Elif(m_in.valid):
-# index := get_index(m_in.addr);
- sync += index.eq(get_index(m_in.addr))
-
-# else
+ comb += index.eq(get_index(m_in.addr))
with m.Else():
-# index := get_index(d_in.addr);
- sync += index.eq(get_index(d_in.addr))
-# end if;
-# cache_tag_set <= cache_tags(index);
+ comb += index.eq(get_index(d_in.addr))
sync += cache_tag_set.eq(cache_tags[index])
-# end if;
-# end process;
- # Cache request parsing and hit detection
- def dcache_request(self, r0, ra, req_index, req_row, req_tag,
- r0_valid, r1, cache_valid_bits, replace_way,
+ def dcache_request(self, m, r0, ra, req_index, req_row, req_tag,
+ r0_valid, r1, cache_valids, replace_way,
use_forward1_next, use_forward2_next,
req_hit_way, plru_victim, rc_ok, perm_attr,
- valid_ra, perm_ok, access_ok, req_op, req_ok,
- r0_stall, m_in, early_req_row, d_in):
+ valid_ra, perm_ok, access_ok, req_op, req_go,
+ tlb_pte_way,
+ tlb_hit, tlb_hit_way, tlb_valid_way, cache_tag_set,
+ cancel_store, req_same_tag, r0_stall, early_req_row):
+ """Cache request parsing and hit detection
+ """
comb = m.d.comb
sync = m.d.sync
+ m_in, d_in = self.m_in, self.d_in
-# variable is_hit : std_ulogic;
-# variable hit_way : way_t;
-# variable op : op_t;
-# variable opsel : std_ulogic_vector(2 downto 0);
-# variable go : std_ulogic;
-# variable nc : std_ulogic;
-# 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 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
-# );
- rel_match = Signal()
is_hit = Signal()
hit_way = Signal(WAY_BITS)
- op = Op()
+ op = Signal(Op)
opsel = Signal(3)
go = Signal()
nc = Signal()
- s_hit = Signal()
- s_tag = Signal(TAG_BITS)
- s_pte = Signal(TLB_PTE_BITS)
- s_ra = Signal(REAL_ADDR_BITS)
- hit_set = Signal(TLB_NUM_WAYS)
- hit_way_set = HitWaySet()
- rel_matches = Signal(TLB_NUM_WAYS)
- rel_match = Signal()
-
- comb += rel_match
- comb += is_hit
- comb += hit_way
- comb += op
- comb += opsel
- comb += go
- comb += nc
- comb += s_hit
- comb += s_tag
- comb += s_pte
- comb += s_ra
- comb += hit_set
- comb += hit_way_set
- comb += rel_matches
- comb += rel_match
-
-# begin
-# -- Extract line, row and tag from request
-# req_index <= get_index(r0.req.addr);
-# req_row <= get_row(r0.req.addr);
-# req_tag <= get_tag(ra);
-#
-# go := r0_valid and not (r0.tlbie or r0.tlbld)
-# and not r1.ls_error;
+ hit_set = Array(Signal(name="hit_set_%d" % i) \
+ for i in range(TLB_NUM_WAYS))
+ cache_valid_idx = Signal(NUM_WAYS)
+
# Extract line, row and tag from request
comb += req_index.eq(get_index(r0.req.addr))
comb += req_row.eq(get_row(r0.req.addr))
comb += req_tag.eq(get_tag(ra))
- comb += go.eq(r0_valid & ~(r0.tlbie | r0.tlbld) & ~r1.ls_error)
-
-# hit_way := 0;
-# is_hit := '0';
-# rel_match := '0';
- # Test if pending request is a hit on any way
- # In order to make timing in virtual mode,
- # when we are using the TLB, we compare each
- # way with each of the real addresses from each way of
- # the TLB, and then decide later which match to use.
- comb += hit_way.eq(0)
- comb += is_hit.eq(0)
- comb += rel_match.eq(0)
+ if False: # display on comb is a bit... busy.
+ comb += Display("dcache_req addr:%x ra: %x idx: %x tag: %x row: %x",
+ r0.req.addr, ra, req_index, req_tag, req_row)
-# if r0.req.virt_mode = '1' then
- with m.If(r0.req.virt_mode):
-# rel_matches := (others => '0');
- comb += rel_matches.eq(0)
-# for j in tlb_way_t loop
- for j in range(TLB_NUM_WAYS):
-# hit_way_set(j) := 0;
-# s_hit := '0';
-# s_pte := read_tlb_pte(j, tlb_pte_way);
-# s_ra := s_pte(REAL_ADDR_BITS - 1 downto TLB_LG_PGSZ)
-# & r0.req.addr(TLB_LG_PGSZ - 1 downto 0);
-# s_tag := get_tag(s_ra);
- comb += hit_way_set[j].eq(0)
- comb += s_hit.eq(0)
- comb += s_pte.eq(read_tlb_pte(j, tlb_pte_way))
- comb += s_ra.eq(Cat(
- r0.req.addr[0:TLB_LG_PGSZ],
- s_pte[TLB_LG_PGSZ:REAL_ADDR_BITS]
- ))
- comb += s_tag.eq(get_tag(s_ra))
-
-# for i in way_t loop
- for i in range(NUM_WAYS):
-# if go = '1' and cache_valids(req_index)(i) = '1'
-# and read_tag(i, cache_tag_set) = s_tag
-# and tlb_valid_way(j) = '1' then
- with m.If(go & cache_valid_bits[req_index][i] &
- read_tag(i, cache_tag_set) == s_tag
- & tlb_valid_way[j]):
-# hit_way_set(j) := i;
-# s_hit := '1';
- comb += hit_way_set[j].eq(i)
- comb += s_hit.eq(1)
-# end if;
-# end loop;
-# hit_set(j) := s_hit;
- comb += hit_set[j].eq(s_hit)
-# if s_tag = r1.reload_tag then
- with m.If(s_tag == r1.reload_tag):
-# rel_matches(j) := '1';
- comb += rel_matches[j].eq(1)
-# end if;
-# end loop;
-# if tlb_hit = '1' then
- with m.If(tlb_hit):
-# is_hit := hit_set(tlb_hit_way);
-# hit_way := hit_way_set(tlb_hit_way);
-# rel_match := rel_matches(tlb_hit_way);
- comb += is_hit.eq(hit_set[tlb_hit_way])
- comb += hit_way.eq(hit_way_set[tlb_hit_way])
- comb += rel_match.eq(rel_matches[tlb_hit_way])
-# end if;
-# else
- with m.Else():
-# s_tag := get_tag(r0.req.addr);
- comb += s_tag.eq(get_tag(r0.req.addr))
-# for i in way_t loop
- for i in range(NUM_WAYS):
-# if go = '1' and cache_valids(req_index)(i) = '1' and
-# read_tag(i, cache_tag_set) = s_tag then
- with m.If(go & cache_valid_bits[req_index][i] &
- read_tag(i, cache_tag_set) == s_tag):
-# hit_way := i;
-# is_hit := '1';
- comb += hit_way.eq(i)
- comb += is_hit.eq(1)
-# end if;
-# end loop;
-# if s_tag = r1.reload_tag then
- with m.If(s_tag == r1.reload_tag):
-# rel_match := '1';
- comb += rel_match.eq(1)
-# end if;
-# end if;
-# req_same_tag <= rel_match;
- comb += req_same_tag.eq(rel_match)
+ comb += go.eq(r0_valid & ~(r0.tlbie | r0.tlbld) & ~r1.ls_error)
+ comb += cache_valid_idx.eq(cache_valids[req_index])
+
+ m.submodules.dcache_pend = dc = DCachePendingHit(tlb_pte_way,
+ tlb_valid_way, tlb_hit_way,
+ cache_valid_idx, cache_tag_set,
+ r0.req.addr,
+ hit_set)
+
+ comb += dc.tlb_hit.eq(tlb_hit)
+ comb += dc.reload_tag.eq(r1.reload_tag)
+ comb += dc.virt_mode.eq(r0.req.virt_mode)
+ comb += dc.go.eq(go)
+ comb += dc.req_index.eq(req_index)
+ comb += is_hit.eq(dc.is_hit)
+ comb += hit_way.eq(dc.hit_way)
+ comb += req_same_tag.eq(dc.rel_match)
-# if r1.state = RELOAD_WAIT_ACK and req_index = r1.store_index
-# and rel_match = '1' then
# See if the request matches the line currently being reloaded
- with m.If(r1.state == State.RELOAD_WAIT_ACK & req_index ==
- r1.store_index & rel_match):
+ with m.If((r1.state == State.RELOAD_WAIT_ACK) &
+ (req_index == r1.store_index) & req_same_tag):
# For a store, consider this a hit even if the row isn't
# valid since it will be by the time we perform the store.
# For a load, check the appropriate row valid bit.
-# is_hit :=
-# not r0.req.load
-# or r1.rows_valid(req_row mod ROW_PER_LINE);
-# hit_way := replace_way;
- comb += is_hit.eq(~r0.req.load
- | r1.rows_valid[req_row % ROW_PER_LINE]
- )
+ rrow = Signal(ROW_LINE_BITS)
+ comb += rrow.eq(req_row)
+ valid = r1.rows_valid[rrow]
+ comb += is_hit.eq(~r0.req.load | valid)
comb += hit_way.eq(replace_way)
-# end if;
-# -- Whether to use forwarded data for a load or not
# Whether to use forwarded data for a load or not
-# use_forward1_next <= '0';
- comb += use_forward1_next.eq(0)
-# if get_row(r1.req.real_addr) = req_row
-# and r1.req.hit_way = hit_way then
- with m.If(get_row(r1.req.real_addr) == req_row
- & r1.req.hit_way == hit_way)
+ with m.If((get_row(r1.req.real_addr) == req_row) &
+ (r1.req.hit_way == hit_way)):
# Only need to consider r1.write_bram here, since if we
# are writing refill data here, then we don't have a
# cache hit this cycle on the line being refilled.
# contents of the victim line, since it is a couple of
# cycles after the refill starts before we see the updated
# cache tag. In that case we don't use the bypass.)
-# use_forward1_next <= r1.write_bram;
comb += use_forward1_next.eq(r1.write_bram)
-# end if;
-# use_forward2_next <= '0';
- comb += use_forward2_next.eq(0)
-# if r1.forward_row1 = req_row
-# and r1.forward_way1 = hit_way then
- with m.If(r1.forward_row1 == req_row
- & r1.forward_way1 == hit_way):
-# use_forward2_next <= r1.forward_valid1;
+ with m.If((r1.forward_row1 == req_row) & (r1.forward_way1 == hit_way)):
comb += use_forward2_next.eq(r1.forward_valid1)
-# end if;
# The way that matched on a hit
-# req_hit_way <= hit_way;
comb += req_hit_way.eq(hit_way)
# The way to replace on a miss
-# if r1.write_tag = '1' then
with m.If(r1.write_tag):
-# replace_way <= to_integer(unsigned(
-# plru_victim(r1.store_index)
-# ));
- replace_way.eq(plru_victim[r1.store_index])
-# else
+ comb += replace_way.eq(plru_victim[r1.store_index])
with m.Else():
-# replace_way <= r1.store_way;
comb += replace_way.eq(r1.store_way)
-# end if;
# work out whether we have permission for this access
# NB we don't yet implement AMR, thus no KUAP
-# rc_ok <= perm_attr.reference and
-# (r0.req.load or perm_attr.changed);
-# perm_ok <= (r0.req.priv_mode or not perm_attr.priv) and
-# (perm_attr.wr_perm or (r0.req.load
-# and perm_attr.rd_perm));
-# access_ok <= valid_ra and perm_ok and rc_ok;
- comb += rc_ok.eq(
- perm_attr.reference
- & (r0.req.load | perm_attr.changed)
+ comb += rc_ok.eq(perm_attr.reference
+ & (r0.req.load | perm_attr.changed)
)
- comb += perm_ok.eq((r0.req.prive_mode | ~perm_attr.priv)
- & perm_attr.wr_perm
- | (r0.req.load & perm_attr.rd_perm)
- )
+ comb += perm_ok.eq((r0.req.priv_mode | ~perm_attr.priv) &
+ (perm_attr.wr_perm |
+ (r0.req.load & perm_attr.rd_perm)))
comb += access_ok.eq(valid_ra & perm_ok & rc_ok)
-# nc := r0.req.nc or perm_attr.nocache;
-# op := OP_NONE;
# Combine the request and cache hit status to decide what
# operation needs to be done
comb += nc.eq(r0.req.nc | perm_attr.nocache)
comb += op.eq(Op.OP_NONE)
-# if go = '1' then
with m.If(go):
-# if access_ok = '0' then
with m.If(~access_ok):
-# op := OP_BAD;
comb += op.eq(Op.OP_BAD)
-# elsif cancel_store = '1' then
with m.Elif(cancel_store):
-# op := OP_STCX_FAIL;
comb += op.eq(Op.OP_STCX_FAIL)
-# else
with m.Else():
-# opsel := r0.req.load & nc & is_hit;
comb += opsel.eq(Cat(is_hit, nc, r0.req.load))
-# case opsel is
with m.Switch(opsel):
-# when "101" => op := OP_LOAD_HIT;
-# when "100" => op := OP_LOAD_MISS;
-# when "110" => op := OP_LOAD_NC;
-# when "001" => op := OP_STORE_HIT;
-# when "000" => op := OP_STORE_MISS;
-# when "010" => op := OP_STORE_MISS;
-# when "011" => op := OP_BAD;
-# when "111" => op := OP_BAD;
-# when others => op := OP_NONE;
- with m.Case(Const(0b101, 3)):
- comb += op.eq(Op.OP_LOAD_HIT)
-
- with m.Case(Cosnt(0b100, 3)):
- comb += op.eq(Op.OP_LOAD_MISS)
-
- with m.Case(Const(0b110, 3)):
- comb += op.eq(Op.OP_LOAD_NC)
-
- with m.Case(Const(0b001, 3)):
- comb += op.eq(Op.OP_STORE_HIT)
-
- with m.Case(Const(0b000, 3)):
- comb += op.eq(Op.OP_STORE_MISS)
-
- with m.Case(Const(0b010, 3)):
- comb += op.eq(Op.OP_STORE_MISS)
-
- with m.Case(Const(0b011, 3)):
- comb += op.eq(Op.OP_BAD)
-
- with m.Case(Const(0b111, 3)):
- comb += op.eq(Op.OP_BAD)
-
- with m.Default():
- comb += op.eq(Op.OP_NONE)
-# end case;
-# end if;
-# end if;
-# req_op <= op;
-# req_go <= go;
+ with m.Case(0b101): comb += op.eq(Op.OP_LOAD_HIT)
+ with m.Case(0b100): comb += op.eq(Op.OP_LOAD_MISS)
+ with m.Case(0b110): comb += op.eq(Op.OP_LOAD_NC)
+ with m.Case(0b001): comb += op.eq(Op.OP_STORE_HIT)
+ with m.Case(0b000): comb += op.eq(Op.OP_STORE_MISS)
+ with m.Case(0b010): comb += op.eq(Op.OP_STORE_MISS)
+ with m.Case(0b011): comb += op.eq(Op.OP_BAD)
+ with m.Case(0b111): comb += op.eq(Op.OP_BAD)
comb += req_op.eq(op)
comb += req_go.eq(go)
# in the cases where we need to read the cache data BRAM.
# If we're stalling then we need to keep reading the last
# row requested.
-# if r0_stall = '0' then
with m.If(~r0_stall):
-# if m_in.valid = '1' then
with m.If(m_in.valid):
-# early_req_row <= get_row(m_in.addr);
comb += early_req_row.eq(get_row(m_in.addr))
-# else
with m.Else():
-# early_req_row <= get_row(d_in.addr);
comb += early_req_row.eq(get_row(d_in.addr))
-# end if;
-# else
with m.Else():
-# early_req_row <= req_row;
comb += early_req_row.eq(req_row)
-# end if;
-# end process;
- # Handle load-with-reservation and store-conditional instructions
- def reservation_comb(self, cancel_store, set_rsrv, clear_rsrv,
+ def reservation_comb(self, m, cancel_store, set_rsrv, clear_rsrv,
r0_valid, r0, reservation):
-
+ """Handle load-with-reservation and store-conditional instructions
+ """
comb = m.d.comb
sync = m.d.sync
-# begin
-# cancel_store <= '0';
-# set_rsrv <= '0';
-# clear_rsrv <= '0';
-# if r0_valid = '1' and r0.req.reserve = '1' then
with m.If(r0_valid & r0.req.reserve):
-
-# -- XXX generate alignment interrupt if address
-# -- is not aligned XXX or if r0.req.nc = '1'
-# if r0.req.load = '1' then
# XXX generate alignment interrupt if address
# is not aligned XXX or if r0.req.nc = '1'
with m.If(r0.req.load):
-# -- load with reservation
-# set_rsrv <= '1';
- # load with reservation
- comb += set_rsrv(1)
-# else
+ comb += set_rsrv.eq(1) # load with reservation
with m.Else():
-# -- store conditional
-# clear_rsrv <= '1';
- # store conditional
- comb += clear_rsrv.eq(1)
-# if reservation.valid = '0' or r0.req.addr(63
-# downto LINE_OFF_BITS) /= reservation.addr then
- with m.If(~reservation.valid
- | r0.req.addr[LINE_OFF_BITS:64]):
-# cancel_store <= '1';
+ comb += clear_rsrv.eq(1) # store conditional
+ with m.If(~reservation.valid |
+ (r0.req.addr[LINE_OFF_BITS:64] != reservation.addr)):
comb += cancel_store.eq(1)
-# end if;
-# end if;
-# end if;
-# end process;
- def reservation_reg(self, r0_valid, access_ok, clear_rsrv,
+ def reservation_reg(self, m, r0_valid, access_ok, set_rsrv, clear_rsrv,
reservation, r0):
comb = m.d.comb
sync = m.d.sync
-# begin
-# if rising_edge(clk) then
-# if rst = '1' then
-# reservation.valid <= '0';
- # TODO understand how resets work in nmigen
-# elsif r0_valid = '1' and access_ok = '1' then
- with m.Elif(r0_valid & access_ok)""
-# if clear_rsrv = '1' then
- with m.If(clear_rsrv):
-# reservation.valid <= '0';
- sync += reservation.valid.ea(0)
-# elsif set_rsrv = '1' then
- with m.Elif(set_rsrv):
-# reservation.valid <= '1';
-# reservation.addr <=
-# r0.req.addr(63 downto LINE_OFF_BITS);
- sync += reservation.valid.eq(1)
- sync += reservation.addr.eq(
- r0.req.addr[LINE_OFF_BITS:64]
- )
-# end if;
-# end if;
-# end if;
-# end process;
-
- # Return data for loads & completion control logic
- def writeback_control(self, r1, cache_out, d_out, m_out):
+ with m.If(r0_valid & access_ok):
+ with m.If(clear_rsrv):
+ sync += reservation.valid.eq(0)
+ with m.Elif(set_rsrv):
+ sync += reservation.valid.eq(1)
+ sync += reservation.addr.eq(r0.req.addr[LINE_OFF_BITS:64])
+ def writeback_control(self, m, r1, cache_out_row):
+ """Return data for loads & completion control logic
+ """
comb = m.d.comb
sync = m.d.sync
+ d_out, m_out = self.d_out, self.m_out
-# variable data_out : std_ulogic_vector(63 downto 0);
-# variable data_fwd : std_ulogic_vector(63 downto 0);
-# variable j : integer;
data_out = Signal(64)
data_fwd = Signal(64)
- j = Signal()
-
-# begin
-# -- Use the bypass if are reading the row that was
-# -- written 1 or 2 cycles ago, including for the
-# -- slow_valid = 1 case (i.e. completing a load
-# -- miss or a non-cacheable load).
-# if r1.use_forward1 = '1' then
+
# Use the bypass if are reading the row that was
# written 1 or 2 cycles ago, including for the
# slow_valid = 1 case (i.e. completing a load
# miss or a non-cacheable load).
with m.If(r1.use_forward1):
-# data_fwd := r1.forward_data1;
comb += data_fwd.eq(r1.forward_data1)
-# else
with m.Else():
-# data_fwd := r1.forward_data2;
comb += data_fwd.eq(r1.forward_data2)
-# end if;
-# data_out := cache_out(r1.hit_way);
- comb += data_out.eq(cache_out[r1.hit_way])
+ comb += data_out.eq(cache_out_row)
-# for i in 0 to 7 loop
for i in range(8):
-# j := i * 8;
- comb += i * 8
-
-# if r1.forward_sel(i) = '1' then
with m.If(r1.forward_sel[i]):
-# data_out(j + 7 downto j) := data_fwd(j + 7 downto j);
- comb += data_out[j:j+8].eq(data_fwd[j:j+8])
-# end if;
-# end loop;
-
-# d_out.valid <= r1.ls_valid;
-# d_out.data <= data_out;
-# d_out.store_done <= not r1.stcx_fail;
-# d_out.error <= r1.ls_error;
-# d_out.cache_paradox <= r1.cache_paradox;
+ dsel = data_fwd.word_select(i, 8)
+ comb += data_out.word_select(i, 8).eq(dsel)
+
comb += d_out.valid.eq(r1.ls_valid)
comb += d_out.data.eq(data_out)
comb += d_out.store_done.eq(~r1.stcx_fail)
comb += d_out.error.eq(r1.ls_error)
comb += d_out.cache_paradox.eq(r1.cache_paradox)
-# -- Outputs to MMU
-# m_out.done <= r1.mmu_done;
-# m_out.err <= r1.mmu_error;
-# m_out.data <= data_out;
+ # Outputs to MMU
comb += m_out.done.eq(r1.mmu_done)
comb += m_out.err.eq(r1.mmu_error)
comb += m_out.data.eq(data_out)
-# -- We have a valid load or store hit or we just completed
-# -- a slow op such as a load miss, a NC load or a store
-# --
-# -- Note: the load hit is delayed by one cycle. However it
-# -- can still not collide with r.slow_valid (well unless I
-# -- miscalculated) because slow_valid can only be set on a
-# -- subsequent request and not on its first cycle (the state
-# -- machine must have advanced), which makes slow_valid
-# -- at least 2 cycles from the previous hit_load_valid.
-#
-# -- Sanity: Only one of these must be set in any given cycle
-# assert (r1.slow_valid and r1.stcx_fail) /= '1'
-# report "unexpected slow_valid collision with stcx_fail"
-# severity FAILURE;
-# assert ((r1.slow_valid or r1.stcx_fail) and r1.hit_load_valid)
-# /= '1' report "unexpected hit_load_delayed collision with
-# slow_valid" severity FAILURE;
# We have a valid load or store hit or we just completed
# a slow op such as a load miss, a NC load or a store
#
# at least 2 cycles from the previous hit_load_valid.
# Sanity: Only one of these must be set in any given cycle
- assert (r1.slow_valid & r1.stcx_fail) != 1 "unexpected" \
- "slow_valid collision with stcx_fail -!- severity FAILURE"
-
- assert ((r1.slow_valid | r1.stcx_fail) | r1.hit_load_valid) != 1
- "unexpected hit_load_delayed collision with slow_valid -!-" \
- "severity FAILURE"
-
-# if r1.mmu_req = '0' then
- with m.If(~r1._mmu_req):
-# -- Request came from loadstore1...
-# -- Load hit case is the standard path
-# if r1.hit_load_valid = '1' then
+
+ if False: # TODO: need Display to get this to work
+ assert (r1.slow_valid & r1.stcx_fail) != 1, \
+ "unexpected slow_valid collision with stcx_fail"
+
+ assert ((r1.slow_valid | r1.stcx_fail) | r1.hit_load_valid) != 1, \
+ "unexpected hit_load_delayed collision with slow_valid"
+
+ with m.If(~r1.mmu_req):
# Request came from loadstore1...
# Load hit case is the standard path
with m.If(r1.hit_load_valid):
-# report
-# "completing load hit data=" & to_hstring(data_out);
- print(f"completing load hit data={data_out}")
-# end if;
+ sync += Display("completing load hit data=%x", data_out)
-# -- error cases complete without stalling
-# if r1.ls_error = '1' then
# error cases complete without stalling
with m.If(r1.ls_error):
-# report "completing ld/st with error";
- print("completing ld/st with error")
-# end if;
+ sync += Display("completing ld/st with error")
-# -- Slow ops (load miss, NC, stores)
-# if r1.slow_valid = '1' then
# Slow ops (load miss, NC, stores)
with m.If(r1.slow_valid):
-# report
-# "completing store or load miss data="
-# & to_hstring(data_out);
- print(f"completing store or load miss data={data_out}")
-# end if;
+ sync += Display("completing store or load miss data=%x",
+ data_out)
-# else
with m.Else():
-# -- Request came from MMU
-# if r1.hit_load_valid = '1' then
# Request came from MMU
with m.If(r1.hit_load_valid):
-# report "completing load hit to MMU, data="
-# & to_hstring(m_out.data);
- print(f"completing load hit to MMU, data={m_out.data}")
-# end if;
-#
-# -- error cases complete without stalling
-# if r1.mmu_error = '1' then
-# report "completing MMU ld with error";
+ sync += Display("completing load hit to MMU, data=%x",
+ m_out.data)
# error cases complete without stalling
with m.If(r1.mmu_error):
- print("combpleting MMU ld with error")
-# end if;
-#
-# -- Slow ops (i.e. load miss)
-# if r1.slow_valid = '1' then
+ sync += Display("combpleting MMU ld with error")
+
# Slow ops (i.e. load miss)
with m.If(r1.slow_valid):
-# report "completing MMU load miss, data="
-# & to_hstring(m_out.data);
- print("completing MMU load miss, data={m_out.data}")
-# end if;
-# end if;
-# end process;
-
-# begin TODO
-# -- Generate a cache RAM for each way. This handles the normal
-# -- reads, writes from reloads and the special store-hit update
-# -- path as well.
-# --
-# -- Note: the BRAMs have an extra read buffer, meaning the output
-# -- is pipelined an extra cycle. This differs from the
-# -- icache. The writeback logic needs to take that into
-# -- account by using 1-cycle delayed signals for load hits.
-# --
-# rams: for i in 0 to NUM_WAYS-1 generate
-# signal do_read : std_ulogic;
-# signal rd_addr : std_ulogic_vector(ROW_BITS-1 downto 0);
-# signal do_write : std_ulogic;
-# signal wr_addr : std_ulogic_vector(ROW_BITS-1 downto 0);
-# signal wr_data :
-# std_ulogic_vector(wishbone_data_bits-1 downto 0);
-# signal wr_sel : std_ulogic_vector(ROW_SIZE-1 downto 0);
-# signal wr_sel_m : std_ulogic_vector(ROW_SIZE-1 downto 0);
-# signal dout : cache_row_t;
-# begin
-# way: entity work.cache_ram
-# generic map (
-# ROW_BITS => ROW_BITS,
-# WIDTH => wishbone_data_bits,
-# ADD_BUF => true
-# )
-# port map (
-# clk => clk,
-# rd_en => do_read,
-# rd_addr => rd_addr,
-# rd_data => dout,
-# wr_sel => wr_sel_m,
-# wr_addr => wr_addr,
-# wr_data => wr_data
-# );
-# process(all)
-# end TODO
-class TODO(Elaboratable):
- def __init__(self):
- pass
-
- def elaborate(self, platform):
- m = Module()
-
+ sync += Display("completing MMU load miss, data=%x",
+ m_out.data)
+
+ def rams(self, m, r1, early_req_row, cache_out_row, replace_way):
+ """rams
+ Generate a cache RAM for each way. This handles the normal
+ reads, writes from reloads and the special store-hit update
+ path as well.
+
+ Note: the BRAMs have an extra read buffer, meaning the output
+ is pipelined an extra cycle. This differs from the
+ icache. The writeback logic needs to take that into
+ account by using 1-cycle delayed signals for load hits.
+ """
comb = m.d.comb
- sync = m.d.sync
-
-# begin
-# -- Cache hit reads
-# do_read <= '1';
-# rd_addr <=
-# std_ulogic_vector(to_unsigned(early_req_row, ROW_BITS));
-# cache_out(i) <= dout;
- # Cache hit reads
- comb += do_read.eq(1)
- comb += rd_addr.eq(Signal(BRAM_ROWS))
- comb += cache_out[i].eq(dout)
-
-# -- Write mux:
-# --
-# -- Defaults to wishbone read responses (cache refill)
-# --
-# -- For timing, the mux on wr_data/sel/addr is not
-# -- dependent on anything other than the current state.
- # Write mux:
- #
- # Defaults to wishbone read responses (cache refill)
- #
- # For timing, the mux on wr_data/sel/addr is not
- # dependent on anything other than the current state.
-# wr_sel_m <= (others => '0');
- comb += wr_sel_m.eq(0)
-
-# do_write <= '0';
- comb += do_write.eq(0)
-# if r1.write_bram = '1' then
- with m.If(r1.write_bram):
-# -- Write store data to BRAM. This happens one
-# -- cycle after the store is in r0.
- # Write store data to BRAM. This happens one
- # cycle after the store is in r0.
-# wr_data <= r1.req.data;
-# wr_sel <= r1.req.byte_sel;
-# wr_addr <= std_ulogic_vector(to_unsigned(
-# get_row(r1.req.real_addr), ROW_BITS
-# ));
- comb += wr_data.eq(r1.req.data)
- comb += wr_sel.eq(r1.req.byte_sel)
- comb += wr_addr.eq(Signal(get_row(r1.req.real_addr)))
-
-# if i = r1.req.hit_way then
- with m.If(i == r1.req.hit_way):
-# do_write <= '1';
- comb += do_write.eq(1)
-# end if;
-# else
+ wb_in = self.wb_in
+
+ for i in range(NUM_WAYS):
+ do_read = Signal(name="do_rd%d" % i)
+ rd_addr = Signal(ROW_BITS)
+ do_write = Signal(name="do_wr%d" % i)
+ wr_addr = Signal(ROW_BITS)
+ wr_data = Signal(WB_DATA_BITS)
+ wr_sel = Signal(ROW_SIZE)
+ wr_sel_m = Signal(ROW_SIZE)
+ _d_out = Signal(WB_DATA_BITS, name="dout_%d" % i)
+
+ way = CacheRam(ROW_BITS, WB_DATA_BITS, ADD_BUF=True)
+ setattr(m.submodules, "cacheram_%d" % i, way)
+
+ comb += way.rd_en.eq(do_read)
+ comb += way.rd_addr.eq(rd_addr)
+ comb += _d_out.eq(way.rd_data_o)
+ comb += way.wr_sel.eq(wr_sel_m)
+ comb += way.wr_addr.eq(wr_addr)
+ comb += way.wr_data.eq(wr_data)
+
+ # Cache hit reads
+ comb += do_read.eq(1)
+ comb += rd_addr.eq(early_req_row[:ROW_BITS])
+ with m.If(r1.hit_way == i):
+ comb += cache_out_row.eq(_d_out)
+
+ # Write mux:
+ #
+ # Defaults to wishbone read responses (cache refill)
+ #
+ # For timing, the mux on wr_data/sel/addr is not
+ # dependent on anything other than the current state.
+
+ with m.If(r1.write_bram):
+ # Write store data to BRAM. This happens one
+ # cycle after the store is in r0.
+ comb += wr_data.eq(r1.req.data)
+ comb += wr_sel.eq(r1.req.byte_sel)
+ comb += wr_addr.eq(get_row(r1.req.real_addr))
+
+ with m.If(i == r1.req.hit_way):
+ comb += do_write.eq(1)
with m.Else():
-# -- Otherwise, we might be doing a reload or a DCBZ
-# if r1.dcbz = '1' then
# Otherwise, we might be doing a reload or a DCBZ
with m.If(r1.dcbz):
-# wr_data <= (others => '0');
comb += wr_data.eq(0)
-# else
with m.Else():
-# wr_data <= wishbone_in.dat;
- comb += wr_data.eq(wishbone_in.dat)
-# end if;
-
-# wr_addr <= std_ulogic_vector(to_unsigned(
-# r1.store_row, ROW_BITS
-# ));
-# wr_sel <= (others => '1');
- comb += wr_addr.eq(Signal(r1.store_row))
- comb += wr_sel.eq(1)
-
-# if r1.state = RELOAD_WAIT_ACK and
-# wishbone_in.ack = '1' and replace_way = i then
- with m.If(r1.state == State.RELOAD_WAIT_ACK
- & wishbone_in.ack & relpace_way == i):
-# do_write <= '1';
+ comb += wr_data.eq(wb_in.dat)
+ comb += wr_addr.eq(r1.store_row)
+ comb += wr_sel.eq(~0) # all 1s
+
+ with m.If((r1.state == State.RELOAD_WAIT_ACK)
+ & wb_in.ack & (replace_way == i)):
comb += do_write.eq(1)
-# end if;
-# end if;
-
-# -- Mask write selects with do_write since BRAM
-# -- doesn't have a global write-enable
-# if do_write = '1' then
-# -- Mask write selects with do_write since BRAM
-# -- doesn't have a global write-enable
+
+ # Mask write selects with do_write since BRAM
+ # doesn't have a global write-enable
with m.If(do_write):
-# wr_sel_m <= wr_sel;
comb += wr_sel_m.eq(wr_sel)
-# end if;
-# end process;
-# end generate;
# Cache hit synchronous machine for the easy case.
# This handles load hits.
# It also handles error cases (TLB miss, cache paradox)
- def dcache_fast_hit(self, req_op, r0_valid, r1, ):
+ def dcache_fast_hit(self, m, req_op, r0_valid, r0, r1,
+ req_hit_way, req_index, req_tag, access_ok,
+ tlb_hit, tlb_hit_way, tlb_req_index):
comb = m.d.comb
sync = m.d.sync
-# begin
-# if rising_edge(clk) then
-# if req_op /= OP_NONE then
with m.If(req_op != Op.OP_NONE):
-# report "op:" & op_t'image(req_op) &
-# " addr:" & to_hstring(r0.req.addr) &
-# " nc:" & std_ulogic'image(r0.req.nc) &
-# " idx:" & integer'image(req_index) &
-# " tag:" & to_hstring(req_tag) &
-# " way: " & integer'image(req_hit_way);
- print(f"op:{req_op} addr:{r0.req.addr} nc: {r0.req.nc}" \
- f"idx:{req_index} tag:{req_tag} way: {req_hit_way}"
- )
-# end if;
-# if r0_valid = '1' then
+ sync += Display("op:%d addr:%x nc: %d idx: %x tag: %x way: %x",
+ req_op, r0.req.addr, r0.req.nc,
+ req_index, req_tag, req_hit_way)
+
with m.If(r0_valid):
-# r1.mmu_req <= r0.mmu_req;
sync += r1.mmu_req.eq(r0.mmu_req)
-# end if;
-# -- Fast path for load/store hits.
-# -- Set signals for the writeback controls.
-# r1.hit_way <= req_hit_way;
-# r1.hit_index <= req_index;
# Fast path for load/store hits.
# Set signals for the writeback controls.
sync += r1.hit_way.eq(req_hit_way)
sync += r1.hit_index.eq(req_index)
-# if req_op = OP_LOAD_HIT then
with m.If(req_op == Op.OP_LOAD_HIT):
-# r1.hit_load_valid <= '1';
sync += r1.hit_load_valid.eq(1)
-
-# else
with m.Else():
-# r1.hit_load_valid <= '0';
sync += r1.hit_load_valid.eq(0)
-# end if;
-# if req_op = OP_LOAD_HIT or req_op = OP_STORE_HIT then
- with m.If(req_op == Op.OP_LOAD_HIT | req_op == Op.OP_STORE_HIT):
-# r1.cache_hit <= '1';
+ with m.If((req_op == Op.OP_LOAD_HIT) | (req_op == Op.OP_STORE_HIT)):
sync += r1.cache_hit.eq(1)
-# else
with m.Else():
-# r1.cache_hit <= '0';
sync += r1.cache_hit.eq(0)
-# end if;
-# if req_op = OP_BAD then
with m.If(req_op == Op.OP_BAD):
-# report "Signalling ld/st error valid_ra=" &
-# std_ulogic'image(valid_ra) & " rc_ok=" &
-# std_ulogic'image(rc_ok) & " perm_ok=" &
-# std_ulogic'image(perm_ok);
- print(f"Signalling ld/st error valid_ra={valid_ra}"
- f"rc_ok={rc_ok} perm_ok={perm_ok}"
-
-# r1.ls_error <= not r0.mmu_req;
-# r1.mmu_error <= r0.mmu_req;
-# r1.cache_paradox <= access_ok;
+ # Display(f"Signalling ld/st error valid_ra={valid_ra}"
+ # f"rc_ok={rc_ok} perm_ok={perm_ok}"
sync += r1.ls_error.eq(~r0.mmu_req)
sync += r1.mmu_error.eq(r0.mmu_req)
sync += r1.cache_paradox.eq(access_ok)
-# else
with m.Else():
-# r1.ls_error <= '0';
-# r1.mmu_error <= '0';
-# r1.cache_paradox <= '0';
sync += r1.ls_error.eq(0)
sync += r1.mmu_error.eq(0)
sync += r1.cache_paradox.eq(0)
-# end if;
-#
-# if req_op = OP_STCX_FAIL then
- with m.If(req_op == Op.OP_STCX_FAIL):
-# r1.stcx_fail <= '1';
- r1.stcx_fail.eq(1)
-# else
- with m.Else():
-# r1.stcx_fail <= '0';
- sync += r1.stcx_fail.eq(0)
-# end if;
-#
-# -- Record TLB hit information for updating TLB PLRU
-# r1.tlb_hit <= tlb_hit;
-# r1.tlb_hit_way <= tlb_hit_way;
-# r1.tlb_hit_index <= tlb_req_index;
- # Record TLB hit information for updating TLB PLRU
- sync += r1.tlb_hit.eq(tlb_hit)
- sync += r1.tlb_hit_way.eq(tlb_hit_way)
- sync += r1.tlb_hit_index.eq(tlb_req_index)
-# end if;
-# end process;
+ with m.If(req_op == Op.OP_STCX_FAIL):
+ r1.stcx_fail.eq(1)
+ with m.Else():
+ sync += r1.stcx_fail.eq(0)
+
+ # Record TLB hit information for updating TLB PLRU
+ sync += r1.tlb_hit.eq(tlb_hit)
+ sync += r1.tlb_hit_way.eq(tlb_hit_way)
+ sync += r1.tlb_hit_index.eq(tlb_req_index)
# Memory accesses are handled by this state machine:
#
#
# All wishbone requests generation is done here.
# This machine operates at stage 1.
- def dcache_slow(self, r1, use_forward1_next, cache_valid_bits, r0,
- r0_valid, req_op, cache_tag, req_go, ra, wb_in):
+ def dcache_slow(self, m, r1, use_forward1_next, use_forward2_next,
+ cache_valids, r0, replace_way,
+ req_hit_way, req_same_tag,
+ r0_valid, req_op, cache_tags, req_go, ra):
comb = m.d.comb
sync = m.d.sync
+ wb_in = self.wb_in
+
+ req = MemAccessRequest("mreq_ds")
+ acks = Signal(3)
+ adjust_acks = Signal(3)
+
+ req_row = Signal(ROW_BITS)
+ req_idx = Signal(INDEX_BITS)
+ req_tag = Signal(TAG_BITS)
+ comb += req_idx.eq(get_index(req.real_addr))
+ comb += req_row.eq(get_row(req.real_addr))
+ comb += req_tag.eq(get_tag(req.real_addr))
-# variable stbs_done : boolean;
-# variable req : mem_access_request_t;
-# variable acks : unsigned(2 downto 0);
- stbs_done = Signal()
- req = MemAccessRequest()
- acks = Signal(3)
-
- comb += stbs_done
- comb += req
- comb += acks
-
-# begin
-# if rising_edge(clk) then
-# r1.use_forward1 <= use_forward1_next;
-# r1.forward_sel <= (others => '0');
sync += r1.use_forward1.eq(use_forward1_next)
sync += r1.forward_sel.eq(0)
-# if use_forward1_next = '1' then
with m.If(use_forward1_next):
-# r1.forward_sel <= r1.req.byte_sel;
sync += r1.forward_sel.eq(r1.req.byte_sel)
-
-# elsif use_forward2_next = '1' then
with m.Elif(use_forward2_next):
-# r1.forward_sel <= r1.forward_sel1;
sync += r1.forward_sel.eq(r1.forward_sel1)
-# end if;
-# r1.forward_data2 <= r1.forward_data1;
sync += r1.forward_data2.eq(r1.forward_data1)
-
-# if r1.write_bram = '1' then
with m.If(r1.write_bram):
-# r1.forward_data1 <= r1.req.data;
-# r1.forward_sel1 <= r1.req.byte_sel;
-# r1.forward_way1 <= r1.req.hit_way;
-# r1.forward_row1 <= get_row(r1.req.real_addr);
-# r1.forward_valid1 <= '1';
sync += r1.forward_data1.eq(r1.req.data)
sync += r1.forward_sel1.eq(r1.req.byte_sel)
sync += r1.forward_way1.eq(r1.req.hit_way)
sync += r1.forward_row1.eq(get_row(r1.req.real_addr))
sync += r1.forward_valid1.eq(1)
-# else
with m.Else():
-
-# if r1.dcbz = '1' then
- with m.If(r1.bcbz):
-# r1.forward_data1 <= (others => '0');
+ with m.If(r1.dcbz):
sync += r1.forward_data1.eq(0)
-
-# else
with m.Else():
-# r1.forward_data1 <= wishbone_in.dat;
sync += r1.forward_data1.eq(wb_in.dat)
-# end if;
-
-# r1.forward_sel1 <= (others => '1');
-# r1.forward_way1 <= replace_way;
-# r1.forward_row1 <= r1.store_row;
-# r1.forward_valid1 <= '0';
- sync += r1.forward_sel1.eq(1)
+ sync += r1.forward_sel1.eq(~0) # all 1s
sync += r1.forward_way1.eq(replace_way)
sync += r1.forward_row1.eq(r1.store_row)
sync += r1.forward_valid1.eq(0)
-# end if;
-
-# -- On reset, clear all valid bits to force misses
-# if rst = '1' then
- # On reset, clear all valid bits to force misses
- # TODO figure out how reset signal works in nmigeni
- with m.If("""TODO RST???"""):
-# for i in index_t loop
- for i in range(NUM_LINES):
-# cache_valids(i) <= (others => '0');
- sync += cache_valid_bits[i].eq(0)
-# end loop;
-
-# r1.state <= IDLE;
-# r1.full <= '0';
-# r1.slow_valid <= '0';
-# r1.wb.cyc <= '0';
-# r1.wb.stb <= '0';
-# r1.ls_valid <= '0';
-# r1.mmu_done <= '0';
- sync += r1.state.eq(State.IDLE)
- sync += r1.full.eq(0)
- sync += r1.slow_valid.eq(0)
- sync += r1.wb.cyc.eq(0)
- sync += r1.wb.stb.eq(0)
- sync += r1.ls_valid.eq(0)
- sync += r1.mmu_done.eq(0)
-
-# -- Not useful normally but helps avoiding
-# -- tons of sim warnings
- # Not useful normally but helps avoiding
- # tons of sim warnings
-# r1.wb.adr <= (others => '0');
- sync += r1.wb.adr.eq(0)
-# else
+
+ # One cycle pulses reset
+ sync += r1.slow_valid.eq(0)
+ sync += r1.write_bram.eq(0)
+ sync += r1.inc_acks.eq(0)
+ sync += r1.dec_acks.eq(0)
+
+ sync += r1.ls_valid.eq(0)
+ # complete tlbies and TLB loads in the third cycle
+ sync += r1.mmu_done.eq(r0_valid & (r0.tlbie | r0.tlbld))
+
+ with m.If((req_op == Op.OP_LOAD_HIT)
+ | (req_op == Op.OP_STCX_FAIL)):
+ with m.If(~r0.mmu_req):
+ sync += r1.ls_valid.eq(1)
+ with m.Else():
+ sync += r1.mmu_done.eq(1)
+
+ with m.If(r1.write_tag):
+ # Store new tag in selected way
+ for i in range(NUM_WAYS):
+ with m.If(i == replace_way):
+ ct = Signal(TAG_RAM_WIDTH)
+ comb += ct.eq(cache_tags[r1.store_index])
+ comb += ct.word_select(i, TAG_WIDTH).eq(r1.reload_tag)
+ sync += cache_tags[r1.store_index].eq(ct)
+ sync += r1.store_way.eq(replace_way)
+ sync += r1.write_tag.eq(0)
+
+ # Take request from r1.req if there is one there,
+ # else from req_op, ra, etc.
+ with m.If(r1.full):
+ comb += req.eq(r1.req)
with m.Else():
-# -- One cycle pulses reset
-# r1.slow_valid <= '0';
-# r1.write_bram <= '0';
-# r1.inc_acks <= '0';
-# r1.dec_acks <= '0';
-#
-# r1.ls_valid <= '0';
-# -- complete tlbies and TLB loads in the third cycle
-# r1.mmu_done <= r0_valid and (r0.tlbie or r0.tlbld);
- # One cycle pulses reset
- sync += r1.slow_valid.eq(0)
- sync += r1.write_bram.eq(0)
- sync += r1.inc_acks.eq(0)
- sync += r1.dec_acks.eq(0)
-
- sync += r1.ls_valid.eq(0)
- # complete tlbies and TLB loads in the third cycle
- sync += r1.mmu_done.eq(r0_valid & (r0.tlbie | r0.tlbld))
-
-# if req_op = OP_LOAD_HIT or req_op = OP_STCX_FAIL then
- with m.If(req_op == Op.OP_LOAD_HIT
- | req_op == Op.OP_STCX_FAIL):
-# if r0.mmu_req = '0' then
- with m.If(~r0.mmu_req):
-# r1.ls_valid <= '1';
- sync += r1.ls_valid.eq(1)
-# else
- with m.Else():
-# r1.mmu_done <= '1';
- sync += r1.mmu_done.eq(1)
-# end if;
-# end if;
-
-# if r1.write_tag = '1' then
- with m.If(r1.write_tag):
-# -- Store new tag in selected way
-# for i in 0 to NUM_WAYS-1 loop
- # Store new tag in selected way
- for i in range(NUM_WAYS):
-# if i = replace_way then
- with m.If(i == replace_way):
-# cache_tags(r1.store_index)(
-# (i + 1) * TAG_WIDTH - 1
-# downto i * TAG_WIDTH
-# ) <=
-# (TAG_WIDTH - 1 downto TAG_BITS => '0')
-# & r1.reload_tag;
- sync += cache_tag[
- r1.store_index
- ][i * TAG_WIDTH:(i +1) * TAG_WIDTH].eq(
- Const(TAG_WIDTH, TAG_WIDTH)
- & r1.reload_tag
- )
-# end if;
-# end loop;
-# r1.store_way <= replace_way;
-# r1.write_tag <= '0';
- sync += r1.store_way.eq(replace_way)
- sync += r1.write_tag.eq(0)
-# end if;
-
-# -- Take request from r1.req if there is one there,
-# -- else from req_op, ra, etc.
-# if r1.full = '1' then
- # Take request from r1.req if there is one there,
- # else from req_op, ra, etc.
- with m.If(r1.full)
-# req := r1.req;
- sync += req.eq(r1.req)
-
-# else
+ comb += req.op.eq(req_op)
+ comb += req.valid.eq(req_go)
+ comb += req.mmu_req.eq(r0.mmu_req)
+ comb += req.dcbz.eq(r0.req.dcbz)
+ comb += req.real_addr.eq(ra)
+
+ with m.If(~r0.req.dcbz):
+ comb += req.data.eq(r0.req.data)
with m.Else():
-# req.op := req_op;
-# req.valid := req_go;
-# req.mmu_req := r0.mmu_req;
-# req.dcbz := r0.req.dcbz;
-# req.real_addr := ra;
- sync += req.op.eq(req_op)
- sync += req.valid.eq(req_go)
- sync += req.mmu_req.eq(r0.mmu_req)
- sync += req.dcbz.eq(r0.req.dcbz)
- sync += req.real_addr.eq(ra)
-
-# -- Force data to 0 for dcbz
-# if r0.req.dcbz = '0' then
- with m.If(~r0.req.dcbz):
-# req.data := r0.req.data;
- sync += req.data.eq(r0.req.data)
-
-# else
- with m.Else():
-# req.data := (others => '0');
- sync += req.data.eq(0)
-# end if;
-
-# -- Select all bytes for dcbz
-# -- and for cacheable loads
-# if r0.req.dcbz = '1'
-# or (r0.req.load = '1' and r0.req.nc = '0') then
- # Select all bytes for dcbz
- # and for cacheable loads
- with m.If(r0.req.dcbz | (r0.req.load & ~r0.req.nc):
-# req.byte_sel := (others => '1');
- sync += req.byte_sel.eq(1)
-
-# else
- with m.Else():
-# req.byte_sel := r0.req.byte_sel;
- sync += req.byte_sel.eq(r0.req.byte_sel)
-# end if;
-
-# req.hit_way := req_hit_way;
-# req.same_tag := req_same_tag;
- sync += req.hit_way.eq(req_hit_way)
- sync += req.same_tag.eq(req_same_tag)
-
-# -- Store the incoming request from r0,
-# -- if it is a slow request
-# -- Note that r1.full = 1 implies req_op = OP_NONE
-# if req_op = OP_LOAD_MISS or req_op = OP_LOAD_NC
-# or req_op = OP_STORE_MISS
-# or req_op = OP_STORE_HIT then
- # Store the incoming request from r0,
- # if it is a slow request
- # Note that r1.full = 1 implies req_op = OP_NONE
- with m.If(req_op == Op.OP_LOAD_MISS
- | req_op == Op.OP_LOAD_NC
- | req_op == Op.OP_STORE_MISS
- | req_op == Op.OP_STORE_HIT):
-# r1.req <= req;
-# r1.full <= '1';
- sync += r1.req(req)
- sync += r1.full.eq(1)
-# end if;
-# end if;
-#
-# -- Main state machine
-# case r1.state is
- # Main state machine
- with m.Switch(r1.state):
-
-# when IDLE =>
- with m.Case(State.IDLE)
-# r1.wb.adr <= req.real_addr(
-# r1.wb.adr'left downto 0
-# );
-# r1.wb.sel <= req.byte_sel;
-# r1.wb.dat <= req.data;
-# r1.dcbz <= req.dcbz;
-#
-# -- Keep track of our index and way
-# -- for subsequent stores.
-# r1.store_index <= get_index(req.real_addr);
-# r1.store_row <= get_row(req.real_addr);
-# r1.end_row_ix <=
-# get_row_of_line(get_row(req.real_addr)) - 1;
-# r1.reload_tag <= get_tag(req.real_addr);
-# r1.req.same_tag <= '1';
- sync += r1.wb.adr.eq(req.real_addr[0:r1.wb.adr])
- sync += r1.wb.sel.eq(req.byte_sel)
- sync += r1.wb.dat.eq(req.data)
- sync += r1.dcbz.eq(req.dcbz)
-
- # Keep track of our index and way
- # for subsequent stores.
- sync += r1.store_index.eq(get_index(req.real_addr))
- sync += r1.store_row.eq(get_row(req.real_addr))
- sync += r1.end_row_ix.eq(
- get_row_of_line(get_row(req.real_addr))
- )
- sync += r1.reload_tag.eq(get_tag(req.real_addr))
- sync += r1.req.same_tag.eq(1)
-
-# if req.op = OP_STORE_HIT theni
- with m.If(req.op == Op.OP_STORE_HIT):
-# r1.store_way <= req.hit_way;
- sync += r1.store_way.eq(req.hit_way)
-# end if;
-
-# -- Reset per-row valid bits,
-# -- ready for handling OP_LOAD_MISS
-# for i in 0 to ROW_PER_LINE - 1 loop
- # Reset per-row valid bits,
- # ready for handling OP_LOAD_MISS
- for i in range(ROW_PER_LINE):
-# r1.rows_valid(i) <= '0';
- sync += r1.rows_valid[i].eq(0)
-# end loop;
-
-# case req.op is
- with m.Switch(req.op):
-# when OP_LOAD_HIT =>
- with m.Case(Op.OP_LOAD_HIT):
-# -- stay in IDLE state
- # stay in IDLE state
- pass
-
-# when OP_LOAD_MISS =>
- with m.Case(Op.OP_LOAD_MISS):
-# -- Normal load cache miss,
-# -- start the reload machine
-# report "cache miss real addr:" &
-# to_hstring(req.real_addr) & " idx:" &
-# integer'image(get_index(req.real_addr)) &
-# " tag:" & to_hstring(get_tag(req.real_addr));
- # Normal load cache miss,
- # start the reload machine
- print(f"cache miss real addr:" \
- f"{req_real_addr}" \
- f" idx:{get_index(req_real_addr)}" \
- f" tag:{get_tag(req.real_addr)}")
-
-# -- Start the wishbone cycle
-# r1.wb.we <= '0';
-# r1.wb.cyc <= '1';
-# r1.wb.stb <= '1';
- # Start the wishbone cycle
- sync += r1.wb.we.eq(0)
- sync += r1.wb.cyc.eq(1)
- sync += r1.wb.stb.eq(1)
-
-# -- Track that we had one request sent
-# r1.state <= RELOAD_WAIT_ACK;
-# r1.write_tag <= '1';
- # Track that we had one request sent
- sync += r1.state.eq(State.RELOAD_WAIT_ACK)
- sync += r1.write_tag.eq(1)
-
-# when OP_LOAD_NC =>
- with m.Case(Op.OP_LOAD_NC):
-# r1.wb.cyc <= '1';
-# r1.wb.stb <= '1';
-# r1.wb.we <= '0';
-# r1.state <= NC_LOAD_WAIT_ACK;
- sync += r1.wb.cyc.eq(1)
- sync += r1.wb.stb.eq(1)
- sync += r1.wb.we.eq(0)
- sync += r1.state.eq(State.NC_LOAD_WAIT_ACK)
-
-# when OP_STORE_HIT | OP_STORE_MISS =>
- with m.Case(Op.OP_STORE_HIT
- | Op.OP_STORE_MISS):
-# if req.dcbz = '0' then
- with m.If(~req.bcbz):
-# r1.state <= STORE_WAIT_ACK;
-# r1.acks_pending <= to_unsigned(1, 3);
-# r1.full <= '0';
-# r1.slow_valid <= '1';
- sync += r1.state.eq(
- State.STORE_WAIT_ACK
- )
- sync += r1.acks_pending.eq(
- '''TODO to_unsignes(1,3)'''
- )
- sync += r1.full.eq(0)
- sync += r1.slow_valid.eq(1)
-
-# if req.mmu_req = '0' then
- with m.If(~req.mmu_req):
-# r1.ls_valid <= '1';
- sync += r1.ls_valid.eq(1)
-# else
- with m.Else():
-# r1.mmu_done <= '1';
- sync += r1.mmu_done.eq(1)
-# end if;
-
-# if req.op = OP_STORE_HIT then
- with m.If(req.op == Op.OP_STORE_HIT):
-# r1.write_bram <= '1';
- sync += r1.write_bram.eq(1)
-# end if;
-
-# else
- with m.Else():
-# -- dcbz is handled much like a load
-# -- miss except that we are writing
-# -- to memory instead of reading
-# r1.state <= RELOAD_WAIT_ACK;
- # dcbz is handled much like a load
- # miss except that we are writing
- # to memory instead of reading
- sync += r1.state.eq(Op.RELOAD_WAIT_ACK)
-
-# if req.op = OP_STORE_MISS then
- with m.If(req.op == Op.OP_STORE_MISS):
-# r1.write_tag <= '1';
- sync += r1.write_tag.eq(1)
-# end if;
-# end if;
-
-# r1.wb.we <= '1';
-# r1.wb.cyc <= '1';
-# r1.wb.stb <= '1';
- sync += r1.wb.we.eq(1)
- sync += r1.wb.cyc.eq(1)
- sync += r1.wb.stb.eq(1)
-
-# -- OP_NONE and OP_BAD do nothing
-# -- OP_BAD & OP_STCX_FAIL were handled above already
-# when OP_NONE =>
-# when OP_BAD =>
-# when OP_STCX_FAIL =>
- # OP_NONE and OP_BAD do nothing
- # OP_BAD & OP_STCX_FAIL were
- # handled above already
- with m.Case(Op.OP_NONE):
- pass
-
- with m.Case(OP_BAD):
- pass
-
- with m.Case(OP_STCX_FAIL):
- pass
-# end case;
-
-# when RELOAD_WAIT_ACK =>
- with m.Case(State.RELOAD_WAIT_ACK):
-# -- Requests are all sent if stb is 0
- # Requests are all sent if stb is 0
- sync += stbs_done.eq(~r1.wb.stb)
-# stbs_done := r1.wb.stb = '0';
-
-# -- If we are still sending requests,
-# -- was one accepted?
-# if wishbone_in.stall = '0' and not stbs_done then
- # If we are still sending requests,
- # was one accepted?
- with m.If(~wb_in.stall & ~stbs_done):
-# -- That was the last word ? We are done sending.
-# -- Clear stb and set stbs_done so we can handle
-# -- an eventual last ack on the same cycle.
-# if is_last_row_addr(
-# r1.wb.adr, r1.end_row_ix
-# ) then
- # That was the last word?
- # We are done sending.
- # Clear stb and set stbs_done
- # so we can handle an eventual
- # last ack on the same cycle.
- with m.If(is_last_row_addr(
- r1.wb.adr, r1.end_row_ix)):
-# r1.wb.stb <= '0';
-# stbs_done := true;
- sync += r1.wb.stb.eq(0)
- sync += stbs_done.eq(0)
-# end if;
-
-# -- Calculate the next row address
-# r1.wb.adr <= next_row_addr(r1.wb.adr);
- # Calculate the next row address
- sync += r1.wb.adr.eq(next_row_addr(r1.wb.adr))
-# end if;
-
-# -- Incoming acks processing
-# r1.forward_valid1 <= wishbone_in.ack;
- # Incoming acks processing
- sync += r1.forward_valid1.eq(wb_in.ack)
-
-# if wishbone_in.ack = '1' then
- with m.If(wb_in.ack):
-# r1.rows_valid(
-# r1.store_row mod ROW_PER_LINE
-# ) <= '1';
- sync += r1.rows_valid[
- r1.store_row % ROW_PER_LINE
- ].eq(1)
-
-# -- If this is the data we were looking for,
-# -- we can complete the request next cycle.
-# -- Compare the whole address in case the
-# -- request in r1.req is not the one that
-# -- started this refill.
-# if r1.full = '1' and r1.req.same_tag = '1'
-# and ((r1.dcbz = '1' and r1.req.dcbz = '1')
-# or (r1.dcbz = '0' and r1.req.op = OP_LOAD_MISS))
-# and r1.store_row = get_row(r1.req.real_addr) then
- # If this is the data we were looking for,
- # we can complete the request next cycle.
- # Compare the whole address in case the
- # request in r1.req is not the one that
- # started this refill.
- with m.If(r1.full & r1.req.same_tag &
- ((r1.dcbz & r1.req.dcbz)
- (~r1.dcbz &
- r1.req.op == Op.OP_LOAD_MISS)
- ) &
- r1.store_row
- == get_row(r1.req.real_addr):
-# r1.full <= '0';
-# r1.slow_valid <= '1';
- sync += r1.full.eq(0)
- sync += r1.slow_valid.eq(1)
-
-# if r1.mmu_req = '0' then
- with m.If(~r1.mmu_req):
-# r1.ls_valid <= '1';
- sync += r1.ls_valid.eq(1)
-# else
- with m.Else():
-# r1.mmu_done <= '1';
- sync += r1.mmu_done.eq(1)
-# end if;
-# r1.forward_sel <= (others => '1');
-# r1.use_forward1 <= '1';
- sync += r1.forward_sel.eq(1)
- sync += r1.use_forward1.eq(1)
-# end if;
-
-# -- Check for completion
-# if stbs_done and is_last_row(r1.store_row,
-# r1.end_row_ix) then
- # Check for completion
- with m.If(stbs_done &
- is_last_row(r1.store_row,
- r1.end_row_ix)):
-
-# -- Complete wishbone cycle
-# r1.wb.cyc <= '0';
- # Complete wishbone cycle
- sync += r1.wb.cyc.eq(0)
-
-# -- Cache line is now valid
-# cache_valids(r1.store_index)(
-# r1.store_way
-# ) <= '1';
- # Cache line is now valid
- sync += cache_valid_bits[
- r1.store_index
- ][r1.store_way].eq(1)
-
-# r1.state <= IDLE;
- sync += r1.state.eq(State.IDLE)
-# end if;
-
-# -- Increment store row counter
-# r1.store_row <= next_row(r1.store_row);
- # Increment store row counter
- sync += r1.store_row.eq(next_row(
- r1.store_row
- ))
-# end if;
-
-# when STORE_WAIT_ACK =>
- with m.Case(State.STORE_WAIT_ACK):
-# stbs_done := r1.wb.stb = '0';
-# acks := r1.acks_pending;
- sync += stbs_done.eq(~r1.wb.stb)
- sync += acks.eq(r1.acks_pending)
-
-# if r1.inc_acks /= r1.dec_acks then
- with m.If(r1.inc_acks != r1.dec_acks):
-
-# if r1.inc_acks = '1' then
- with m.If(r1.inc_acks):
-# acks := acks + 1;
- sync += acks.eq(acks + 1)
-
-# else
- with m.Else():
-# acks := acks - 1;
- sync += acks.eq(acks - 1)
-# end if;
-# end if;
-
-# r1.acks_pending <= acks;
- sync += r1.acks_pending.eq(acks)
-
-# -- Clear stb when slave accepted request
-# if wishbone_in.stall = '0' then
- # Clear stb when slave accepted request
- with m.If(~wb_in.stall):
-# -- See if there is another store waiting
-# -- to be done which is in the same real page.
-# if req.valid = '1' then
- # See if there is another store waiting
- # to be done which is in the same real page.
- with m.If(req.valid):
-# r1.wb.adr(
-# SET_SIZE_BITS - 1 downto 0
-# ) <= req.real_addr(
-# SET_SIZE_BITS - 1 downto 0
-# );
-# r1.wb.dat <= req.data;
-# r1.wb.sel <= req.byte_sel;
- sync += r1.wb.adr[0:SET_SIZE_BITS].eq(
- req.real_addr[0:SET_SIZE_BITS]
- )
-# end if;
-
-# if acks < 7 and req.same_tag = '1'
-# and (req.op = OP_STORE_MISS
-# or req.op = OP_STORE_HIT) then
- with m.Elif(acks < 7 & req.same_tag &
- (req.op == Op.Op_STORE_MISS
- | req.op == Op.OP_SOTRE_HIT)):
-# r1.wb.stb <= '1';
-# stbs_done := false;
- sync += r1.wb.stb.eq(1)
- sync += stbs_done.eq(0)
-
-# if req.op = OP_STORE_HIT then
- with m.If(req.op == Op.OP_STORE_HIT):
-# r1.write_bram <= '1';
- sync += r1.write_bram.eq(1)
-# end if;
-# r1.full <= '0';
-# r1.slow_valid <= '1';
- sync += r1.full.eq(0)
- sync += r1.slow_valid.eq(1)
-
-# -- Store requests never come from the MMU
-# r1.ls_valid <= '1';
-# stbs_done := false;
-# r1.inc_acks <= '1';
- # Store request never come from the MMU
- sync += r1.ls_valid.eq(1)
- sync += stbs_done.eq(0)
- sync += r1.inc_acks.eq(1)
-# else
- with m.Else():
-# r1.wb.stb <= '0';
-# stbs_done := true;
- sync += r1.wb.stb.eq(0)
- sync += stbs_done.eq(1)
-# end if;
-# end if;
-
-# -- Got ack ? See if complete.
-# if wishbone_in.ack = '1' then
- # Got ack ? See if complete.
- with m.If(wb_in.ack):
-# if stbs_done and acks = 1 then
- with m.If(stbs_done & acks)
-# r1.state <= IDLE;
-# r1.wb.cyc <= '0';
-# r1.wb.stb <= '0';
- sync += r1.state.eq(State.IDLE)
- sync += r1.wb.cyc.eq(0)
- sync += r1.wb.stb.eq(0)
-# end if;
-# r1.dec_acks <= '1';
- sync += r1.dec_acks.eq(1)
-# end if;
-
-# when NC_LOAD_WAIT_ACK =>
- with m.Case(State.NC_LOAD_WAIT_ACK):
-# -- Clear stb when slave accepted request
-# if wishbone_in.stall = '0' then
- # Clear stb when slave accepted request
- with m.If(~wb_in.stall):
-# r1.wb.stb <= '0';
- sync += r1.wb.stb.eq(0)
-# end if;
-
-# -- Got ack ? complete.
-# if wishbone_in.ack = '1' then
- # Got ack ? complete.
- with m.If(wb_in.ack):
-# r1.state <= IDLE;
-# r1.full <= '0';
-# r1.slow_valid <= '1';
- sync += r1.state.eq(State.IDLE)
+ comb += req.data.eq(0)
+
+ # Select all bytes for dcbz
+ # and for cacheable loads
+ with m.If(r0.req.dcbz | (r0.req.load & ~r0.req.nc)):
+ comb += req.byte_sel.eq(~0) # all 1s
+ with m.Else():
+ comb += req.byte_sel.eq(r0.req.byte_sel)
+ comb += req.hit_way.eq(req_hit_way)
+ comb += req.same_tag.eq(req_same_tag)
+
+ # Store the incoming request from r0,
+ # if it is a slow request
+ # Note that r1.full = 1 implies req_op = OP_NONE
+ with m.If((req_op == Op.OP_LOAD_MISS)
+ | (req_op == Op.OP_LOAD_NC)
+ | (req_op == Op.OP_STORE_MISS)
+ | (req_op == Op.OP_STORE_HIT)):
+ sync += r1.req.eq(req)
+ sync += r1.full.eq(1)
+
+ # Main state machine
+ with m.Switch(r1.state):
+
+ with m.Case(State.IDLE):
+ sync += r1.real_adr.eq(req.real_addr)
+ sync += r1.wb.sel.eq(req.byte_sel)
+ sync += r1.wb.dat.eq(req.data)
+ sync += r1.dcbz.eq(req.dcbz)
+
+ # Keep track of our index and way
+ # for subsequent stores.
+ sync += r1.store_index.eq(req_idx)
+ sync += r1.store_row.eq(req_row)
+ sync += r1.end_row_ix.eq(get_row_of_line(req_row))
+ sync += r1.reload_tag.eq(req_tag)
+ sync += r1.req.same_tag.eq(1)
+
+ with m.If(req.op == Op.OP_STORE_HIT):
+ sync += r1.store_way.eq(req.hit_way)
+
+ # Reset per-row valid bits,
+ # ready for handling OP_LOAD_MISS
+ for i in range(ROW_PER_LINE):
+ sync += r1.rows_valid[i].eq(0)
+
+ with m.If(req_op != Op.OP_NONE):
+ sync += Display("cache op %d", req.op)
+
+ with m.Switch(req.op):
+ with m.Case(Op.OP_LOAD_HIT):
+ # stay in IDLE state
+ pass
+
+ with m.Case(Op.OP_LOAD_MISS):
+ sync += Display("cache miss real addr: %x " \
+ "idx: %x tag: %x",
+ req.real_addr, req_row, req_tag)
+
+ # Start the wishbone cycle
+ sync += r1.wb.we.eq(0)
+ sync += r1.wb.cyc.eq(1)
+ sync += r1.wb.stb.eq(1)
+
+ # Track that we had one request sent
+ sync += r1.state.eq(State.RELOAD_WAIT_ACK)
+ sync += r1.write_tag.eq(1)
+
+ with m.Case(Op.OP_LOAD_NC):
+ sync += r1.wb.cyc.eq(1)
+ sync += r1.wb.stb.eq(1)
+ sync += r1.wb.we.eq(0)
+ sync += r1.state.eq(State.NC_LOAD_WAIT_ACK)
+
+ with m.Case(Op.OP_STORE_HIT, Op.OP_STORE_MISS):
+ with m.If(~req.dcbz):
+ sync += r1.state.eq(State.STORE_WAIT_ACK)
+ sync += r1.acks_pending.eq(1)
sync += r1.full.eq(0)
sync += r1.slow_valid.eq(1)
-# if r1.mmu_req = '0' then
- with m.If(~r1.mmu_req):
-# r1.ls_valid <= '1';
+ with m.If(~req.mmu_req):
sync += r1.ls_valid.eq(1)
-
-# else
with m.Else():
-# r1.mmu_done <= '1';
sync += r1.mmu_done.eq(1)
-# end if;
-
-# r1.forward_sel <= (others => '1');
-# r1.use_forward1 <= '1';
-# r1.wb.cyc <= '0';
-# r1.wb.stb <= '0';
- sync += r1.forward_sel.eq(1)
- sync += r1.use_forward1.eq(1)
- sync += r1.wb.cyc.eq(0)
- sync += r1.wb.stb.eq(0)
-# end if;
-# end case;
-# end if;
-# end if;
-# end process;
-
-# dc_log: if LOG_LENGTH > 0 generate
-# TODO learn how to tranlate vhdl generate into nmigen
- def dcache_log(self, r1, valid_ra, tlb_hit_way, stall_out,
- d_out, wb_in, log_out):
-
- comb = m.d.comb
- sync = m.d.sync
-
-# signal log_data : std_ulogic_vector(19 downto 0);
- log_data = Signal(20)
-
- comb += log_data
-
-# begin
-# dcache_log: process(clk)
-# begin
-# if rising_edge(clk) then
-# log_data <= r1.wb.adr(5 downto 3) &
-# wishbone_in.stall &
-# wishbone_in.ack &
-# r1.wb.stb & r1.wb.cyc &
-# d_out.error &
-# d_out.valid &
-# std_ulogic_vector(
-# to_unsigned(op_t'pos(req_op), 3)) &
-# stall_out &
-# std_ulogic_vector(
-# to_unsigned(tlb_hit_way, 3)) &
-# valid_ra &
-# std_ulogic_vector(
-# to_unsigned(state_t'pos(r1.state), 3));
- sync += log_data.eq(Cat(
- Const(r1.state, 3), valid_ra, Const(tlb_hit_way, 3),
- stall_out, Const(req_op, 3), d_out.valid, d_out.error,
- r1.wb.cyc, r1.wb.stb, wb_in.ack, wb_in.stall,
- r1.wb.adr[3:6]
- ))
-# end if;
-# end process;
-# log_out <= log_data;
- # TODO ??? I am very confused need help
- comb += log_out.eq(log_data)
-# end generate;
-# end;
-
- def elaborate(self, platform):
- LINE_SIZE = self.LINE_SIZE
- NUM_LINES = self.NUM_LINES
- NUM_WAYS = self.NUM_WAYS
- TLB_SET_SIZE = self.TLB_SET_SIZE
- TLB_NUM_WAYS = self.TLB_NUM_WAYS
- TLB_LG_PGSZ = self.TLB_LG_PGSZ
- LOG_LENGTH = self.LOG_LENGTH
-
- # 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 WB, so 64-bits)
- ROW_SIZE = WB_DATA_BITS / 8;
-
- # ROW_PER_LINE is the number of row (wishbone
- # transactions) in a line
- ROW_PER_LINE = LINE_SIZE // ROW_SIZE
- # BRAM_ROWS is the number of rows in BRAM needed
- # to represent the full dcache
- BRAM_ROWS = NUM_LINES * ROW_PER_LINE
-
-
- # Bit fields counts in the address
-
- # REAL_ADDR_BITS is the number of real address
- # bits that we store
- REAL_ADDR_BITS = 56
-
- # ROW_BITS is the number of bits to select a row
- ROW_BITS = log2_int(BRAM_ROWS)
-
- # ROW_LINE_BITS is the number of bits to select
- # a row within a line
- ROW_LINE_BITS = log2_int(ROW_PER_LINE)
-
- # LINE_OFF_BITS is the number of bits for
- # the offset in a cache line
- LINE_OFF_BITS = log2_int(LINE_SIZE)
-
- # ROW_OFF_BITS is the number of bits for
- # the offset in a row
- ROW_OFF_BITS = log2_int(ROW_SIZE)
-
- # INDEX_BITS is the number if bits to
- # select a cache line
- INDEX_BITS = log2_int(NUM_LINES)
-
- # SET_SIZE_BITS is the log base 2 of the set size
- SET_SIZE_BITS = LINE_OFF_BITS + INDEX_BITS
-
- # TAG_BITS is the number of bits of
- # the tag part of the address
- TAG_BITS = REAL_ADDR_BITS - SET_SIZE_BITS
-
- # TAG_WIDTH is the width in bits of each way of the tag RAM
- TAG_WIDTH = TAG_BITS + 7 - ((TAG_BITS + 7) % 8)
-
- # WAY_BITS is the number of bits to select a way
- WAY_BITS = log2_int(NUM_WAYS)
+ with m.If(req.op == Op.OP_STORE_HIT):
+ sync += r1.write_bram.eq(1)
+ with m.Else():
+ # dcbz is handled much like a load miss except
+ # that we are writing to memory instead of reading
+ sync += r1.state.eq(State.RELOAD_WAIT_ACK)
- # Example of layout for 32 lines of 64 bytes:
- #
- # .. tag |index| line |
- # .. | row | |
- # .. | |---| | ROW_LINE_BITS (3)
- # .. | |--- - --| LINE_OFF_BITS (6)
- # .. | |- --| ROW_OFF_BITS (3)
- # .. |----- ---| | ROW_BITS (8)
- # .. |-----| | INDEX_BITS (5)
- # .. --------| | TAG_BITS (45)
+ with m.If(req.op == Op.OP_STORE_MISS):
+ sync += r1.write_tag.eq(1)
+
+ sync += r1.wb.we.eq(1)
+ sync += r1.wb.cyc.eq(1)
+ sync += r1.wb.stb.eq(1)
+
+ # OP_NONE and OP_BAD do nothing
+ # OP_BAD & OP_STCX_FAIL were
+ # handled above already
+ with m.Case(Op.OP_NONE):
+ pass
+ with m.Case(Op.OP_BAD):
+ pass
+ with m.Case(Op.OP_STCX_FAIL):
+ pass
+
+ with m.Case(State.RELOAD_WAIT_ACK):
+ ld_stbs_done = Signal()
+ # Requests are all sent if stb is 0
+ comb += ld_stbs_done.eq(~r1.wb.stb)
+
+ with m.If((~wb_in.stall) & r1.wb.stb):
+ # That was the last word?
+ # We are done sending.
+ # Clear stb and set ld_stbs_done
+ # so we can handle an eventual
+ # last ack on the same cycle.
+ with m.If(is_last_row_addr(r1.real_adr, r1.end_row_ix)):
+ sync += r1.wb.stb.eq(0)
+ comb += ld_stbs_done.eq(1)
+
+ # Calculate the next row address in the current cache line
+ row = Signal(LINE_OFF_BITS-ROW_OFF_BITS)
+ comb += row.eq(r1.real_adr[ROW_OFF_BITS:])
+ sync += r1.real_adr[ROW_OFF_BITS:LINE_OFF_BITS].eq(row+1)
+
+ # Incoming acks processing
+ sync += r1.forward_valid1.eq(wb_in.ack)
+ with m.If(wb_in.ack):
+ srow = Signal(ROW_LINE_BITS)
+ comb += srow.eq(r1.store_row)
+ sync += r1.rows_valid[srow].eq(1)
+
+ # If this is the data we were looking for,
+ # we can complete the request next cycle.
+ # Compare the whole address in case the
+ # request in r1.req is not the one that
+ # started this refill.
+ with m.If(r1.full & r1.req.same_tag &
+ ((r1.dcbz & r1.req.dcbz) |
+ (~r1.dcbz & (r1.req.op == Op.OP_LOAD_MISS))) &
+ (r1.store_row == get_row(r1.req.real_addr))):
+ sync += r1.full.eq(0)
+ sync += r1.slow_valid.eq(1)
+ with m.If(~r1.mmu_req):
+ sync += r1.ls_valid.eq(1)
+ with m.Else():
+ sync += r1.mmu_done.eq(1)
+ sync += r1.forward_sel.eq(~0) # all 1s
+ sync += r1.use_forward1.eq(1)
+
+ # Check for completion
+ with m.If(ld_stbs_done & is_last_row(r1.store_row,
+ r1.end_row_ix)):
+ # Complete wishbone cycle
+ sync += r1.wb.cyc.eq(0)
+
+ # Cache line is now valid
+ cv = Signal(INDEX_BITS)
+ comb += cv.eq(cache_valids[r1.store_index])
+ comb += cv.bit_select(r1.store_way, 1).eq(1)
+ sync += cache_valids[r1.store_index].eq(cv)
+ sync += r1.state.eq(State.IDLE)
+
+ # Increment store row counter
+ sync += r1.store_row.eq(next_row(r1.store_row))
+
+ with m.Case(State.STORE_WAIT_ACK):
+ st_stbs_done = Signal()
+ comb += st_stbs_done.eq(~r1.wb.stb)
+ comb += acks.eq(r1.acks_pending)
+
+ with m.If(r1.inc_acks != r1.dec_acks):
+ with m.If(r1.inc_acks):
+ comb += adjust_acks.eq(acks + 1)
+ with m.Else():
+ comb += adjust_acks.eq(acks - 1)
+ with m.Else():
+ comb += adjust_acks.eq(acks)
+
+ sync += r1.acks_pending.eq(adjust_acks)
+
+ # Clear stb when slave accepted request
+ with m.If(~wb_in.stall):
+ # See if there is another store waiting
+ # to be done which is in the same real page.
+ with m.If(req.valid):
+ ra = req.real_addr[0:SET_SIZE_BITS]
+ sync += r1.real_adr[0:SET_SIZE_BITS].eq(ra)
+ sync += r1.wb.dat.eq(req.data)
+ sync += r1.wb.sel.eq(req.byte_sel)
+
+ with m.Elif((adjust_acks < 7) & req.same_tag &
+ ((req.op == Op.OP_STORE_MISS)
+ | (req.op == Op.OP_STORE_HIT))):
+ sync += r1.wb.stb.eq(1)
+ comb += st_stbs_done.eq(0)
+
+ with m.If(req.op == Op.OP_STORE_HIT):
+ sync += r1.write_bram.eq(1)
+ sync += r1.full.eq(0)
+ sync += r1.slow_valid.eq(1)
+
+ # Store requests never come from the MMU
+ sync += r1.ls_valid.eq(1)
+ comb += st_stbs_done.eq(0)
+ sync += r1.inc_acks.eq(1)
+ with m.Else():
+ sync += r1.wb.stb.eq(0)
+ comb += st_stbs_done.eq(1)
+
+ # Got ack ? See if complete.
+ with m.If(wb_in.ack):
+ with m.If(st_stbs_done & (adjust_acks == 1)):
+ sync += r1.state.eq(State.IDLE)
+ sync += r1.wb.cyc.eq(0)
+ sync += r1.wb.stb.eq(0)
+ sync += r1.dec_acks.eq(1)
+
+ with m.Case(State.NC_LOAD_WAIT_ACK):
+ # Clear stb when slave accepted request
+ with m.If(~wb_in.stall):
+ sync += r1.wb.stb.eq(0)
+
+ # Got ack ? complete.
+ with m.If(wb_in.ack):
+ sync += r1.state.eq(State.IDLE)
+ sync += r1.full.eq(0)
+ sync += r1.slow_valid.eq(1)
+
+ with m.If(~r1.mmu_req):
+ sync += r1.ls_valid.eq(1)
+ with m.Else():
+ sync += r1.mmu_done.eq(1)
+
+ sync += r1.forward_sel.eq(~0) # all 1s
+ sync += r1.use_forward1.eq(1)
+ sync += r1.wb.cyc.eq(0)
+ sync += r1.wb.stb.eq(0)
+
+ def dcache_log(self, m, r1, valid_ra, tlb_hit_way, stall_out):
- TAG_RAM_WIDTH = TAG_WIDTH * NUM_WAYS
+ sync = m.d.sync
+ d_out, wb_in, log_out = self.d_out, self.wb_in, self.log_out
- def CacheTagArray():
- return Array(CacheTagSet() for x in range(NUM_LINES))
+ sync += log_out.eq(Cat(r1.state[:3], valid_ra, tlb_hit_way[:3],
+ stall_out, req_op[:3], d_out.valid, d_out.error,
+ r1.wb.cyc, r1.wb.stb, wb_in.ack, wb_in.stall,
+ r1.real_adr[3:6]))
- def CacheValidBitsArray():
- return Array(CacheWayValidBits() for x in range(NUM_LINES))
+ def elaborate(self, platform):
- def RowPerLineValidArray():
- return Array(Signal() for x in range(ROW_PER_LINE))
+ m = Module()
+ comb = m.d.comb
# Storage. Hopefully "cache_rows" is a BRAM, the rest is LUTs
cache_tags = CacheTagArray()
cache_tag_set = Signal(TAG_RAM_WIDTH)
- cache_valid_bits = CacheValidBitsArray()
+ cache_valids = CacheValidBitsArray()
# TODO attribute ram_style : string;
# TODO attribute ram_style of cache_tags : signal is "distributed";
- # L1 TLB
- TLB_SET_BITS = log2_int(TLB_SET_SIZE)
- TLB_WAY_BITS = log2_int(TLB_NUM_WAYS)
- TLB_EA_TAG_BITS = 64 - (TLB_LG_PGSZ + TLB_SET_BITS)
- TLB_TAG_WAY_BITS = TLB_NUM_WAYS * TLB_EA_TAG_BITS
- TLB_PTE_BITS = 64
- TLB_PTE_WAY_BITS = TLB_NUM_WAYS * TLB_PTE_BITS;
-
- def TLBValidBitsArray():
- return Array(
- Signal(TLB_NUM_WAYS) for x in range(TLB_SET_SIZE)
- )
-
- def TLBTagsArray():
- return Array(
- Signal(TLB_TAG_WAY_BITS) for x in range (TLB_SET_SIZE)
- )
-
- def TLBPtesArray():
- return Array(
- Signal(TLB_PTE_WAY_BITS) for x in range(TLB_SET_SIZE)
- )
-
- def HitWaySet():
- return Array(Signal(NUM_WAYS) for x in range(TLB_NUM_WAYS))
-
-"""note: these are passed to nmigen.hdl.Memory as "attributes".
- don't know how, just that they are.
-"""
+ """note: these are passed to nmigen.hdl.Memory as "attributes".
+ don't know how, just that they are.
+ """
dtlb_valid_bits = TLBValidBitsArray()
dtlb_tags = TLBTagsArray()
dtlb_ptes = TLBPtesArray()
# TODO attribute ram_style of
# dtlb_ptes : signal is "distributed";
- r0 = RegStage0()
+ r0 = RegStage0("r0")
r0_full = Signal()
- r1 = RegStage1()
+ r1 = RegStage1("r1")
reservation = Reservation()
# Async signals on incoming request
- req_index = Signal(NUM_LINES)
- req_row = Signal(BRAM_ROWS)
+ req_index = Signal(INDEX_BITS)
+ req_row = Signal(ROW_BITS)
req_hit_way = Signal(WAY_BITS)
req_tag = Signal(TAG_BITS)
- req_op = Op()
+ req_op = Signal(Op)
req_data = Signal(64)
req_same_tag = Signal()
req_go = Signal()
- early_req_row = Signal(BRAM_ROWS)
+ early_req_row = Signal(ROW_BITS)
cancel_store = Signal()
set_rsrv = Signal()
use_forward1_next = Signal()
use_forward2_next = Signal()
- # Cache RAM interface
- def CacheRamOut():
- return Array(Signal(WB_DATA_BITS) for x in range(NUM_WAYS))
-
- cache_out = CacheRamOut()
-
- # PLRU output interface
- def PLRUOut():
- return Array(Signal(WAY_BITS) for x in range(Index()))
+ cache_out_row = Signal(WB_DATA_BITS)
plru_victim = PLRUOut()
replace_way = Signal(WAY_BITS)
tlb_tag_way = Signal(TLB_TAG_WAY_BITS)
tlb_pte_way = Signal(TLB_PTE_WAY_BITS)
tlb_valid_way = Signal(TLB_NUM_WAYS)
- tlb_req_index = Signal(TLB_SET_SIZE)
+ tlb_req_index = Signal(TLB_SET_BITS)
tlb_hit = Signal()
- tlb_hit_way = Signal(TLB_NUM_WAYS)
+ tlb_hit_way = Signal(TLB_WAY_BITS)
pte = Signal(TLB_PTE_BITS)
ra = Signal(REAL_ADDR_BITS)
valid_ra = Signal()
- perm_attr = PermAttr()
+ perm_attr = PermAttr("dc_perms")
rc_ok = Signal()
perm_ok = Signal()
access_ok = Signal()
- # TLB PLRU output interface
- def TLBPLRUOut():
- return Array(
- Signal(TLB_WAY_BITS) for x in range(TLB_SET_SIZE)
- )
-
tlb_plru_victim = TLBPLRUOut()
- # Helper functions to decode incoming requests
- #
- # Return the cache line index (tag index) for an address
- def get_index(addr):
- return addr[LINE_OFF_BITS:SET_SIZE_BITS]
-
- # Return the cache row index (data memory) for an address
- def get_row(addr):
- return addr[ROW_OFF_BITS:SET_SIZE_BITS]
-
- # Return the index of a row within a line
- def get_row_of_line(row):
- row_v = Signal(ROW_BITS)
- row_v = Signal(row)
- return row_v[0:ROW_LINE_BITS]
-
- # Returns whether this is the last row of a line
- def is_last_row_addr(addr, last):
- return addr[ROW_OFF_BITS:LINE_OFF_BITS] == last
-
- # Returns whether this is the last row of a line
- def is_last_row(row, last):
- return get_row_of_line(row) == last
-
- # Return the address of the next row in the current cache line
- def next_row_addr(addr):
- row_idx = Signal(ROW_LINE_BITS)
- result = WBAddrType()
- # Is there no simpler way in VHDL to
- # generate that 3 bits adder ?
- row_idx = addr[ROW_OFF_BITS:LINE_OFF_BITS]
- row_idx = Signal(row_idx + 1)
- result = addr
- result[ROW_OFF_BITS:LINE_OFF_BITS] = row_idx
- return result
-
- # Return the next row in the current cache line. We use a
- # dedicated function in order to limit the size of the
- # generated adder to be only the bits within a cache line
- # (3 bits with default settings)
- def next_row(row)
- row_v = Signal(ROW_BITS)
- row_idx = Signal(ROW_LINE_BITS)
- result = Signal(ROW_BITS)
-
- row_v = Signal(row)
- row_idx = row_v[ROW_LINE_BITS]
- row_v[0:ROW_LINE_BITS] = Signal(row_idx + 1)
- return row_v
-
- # Get the tag value from the address
- def get_tag(addr):
- return addr[SET_SIZE_BITS:REAL_ADDR_BITS]
-
- # Read a tag from a tag memory row
- def read_tag(way, tagset):
- return tagset[way *TAG_WIDTH:way * TAG_WIDTH + TAG_BITS]
-
- # Read a TLB tag from a TLB tag memory row
- def read_tlb_tag(way, tags):
- j = Signal()
-
- j = way * TLB_EA_TAG_BITS
- return tags[j:j + TLB_EA_TAG_BITS]
-
- # Write a TLB tag to a TLB tag memory row
- def write_tlb_tag(way, tags), tag):
- j = Signal()
-
- j = way * TLB_EA_TAG_BITS
- tags[j:j + TLB_EA_TAG_BITS] = tag
-
- # Read a PTE from a TLB PTE memory row
- def read_tlb_pte(way, ptes):
- j = Signal()
-
- j = way * TLB_PTE_BITS
- return ptes[j:j + TLB_PTE_BITS]
-
- def write_tlb_pte(way, ptes,newpte):
- j = Signal()
-
- j = way * TLB_PTE_BITS
- return ptes[j:j + TLB_PTE_BITS] = newpte
-
- assert (LINE_SIZE % ROW_SIZE) == 0 "LINE_SIZE not " \
- "multiple of ROW_SIZE"
-
- assert (LINE_SIZE % 2) == 0 "LINE_SIZE not power of 2"
-
- assert (NUM_LINES % 2) == 0 "NUM_LINES not power of 2"
-
- assert (ROW_PER_LINE % 2) == 0 "ROW_PER_LINE not" \
- "power of 2"
-
- assert ROW_BITS == (INDEX_BITS + ROW_LINE_BITS) \
- "geometry bits don't add up"
-
- assert (LINE_OFF_BITS = ROW_OFF_BITS + ROW_LINEBITS) \
- "geometry bits don't add up"
-
- assert REAL_ADDR_BITS == (TAG_BITS + INDEX_BITS \
- + LINE_OFF_BITS) "geometry bits don't add up"
-
- assert REAL_ADDR_BITS == (TAG_BITS + ROW_BITS + ROW_OFF_BITS) \
- "geometry bits don't add up"
-
- assert 64 == wishbone_data_bits "Can't yet handle a" \
- "wishbone width that isn't 64-bits"
-
- assert SET_SIZE_BITS <= TLB_LG_PGSZ "Set indexed by" \
- "virtual address"
-
# we don't yet handle collisions between loadstore1 requests
# and MMU requests
- comb += m_out.stall.eq(0)
+ comb += self.m_out.stall.eq(0)
# Hold off the request in r0 when r1 has an uncompleted request
comb += r0_stall.eq(r0_full & r1.full)
comb += r0_valid.eq(r0_full & ~r1.full)
- comb += stall_out.eq(r0_stall)
+ comb += self.stall_out.eq(r0_stall)
# Wire up wishbone request latch out of stage 1
- comb += wishbone_out.eq(r1.wb)
+ comb += r1.wb.adr.eq(r1.real_adr[ROW_OFF_BITS:]) # truncate LSBs
+ comb += self.wb_out.eq(r1.wb)
+
+ # call sub-functions putting everything together, using shared
+ # signals established above
+ self.stage_0(m, r0, r1, r0_full)
+ self.tlb_read(m, r0_stall, tlb_valid_way,
+ tlb_tag_way, tlb_pte_way, dtlb_valid_bits,
+ dtlb_tags, dtlb_ptes)
+ self.tlb_search(m, tlb_req_index, r0, r0_valid,
+ tlb_valid_way, tlb_tag_way, tlb_hit_way,
+ tlb_pte_way, pte, tlb_hit, valid_ra, perm_attr, ra)
+ self.tlb_update(m, r0_valid, r0, dtlb_valid_bits, tlb_req_index,
+ tlb_hit_way, tlb_hit, tlb_plru_victim, tlb_tag_way,
+ dtlb_tags, tlb_pte_way, dtlb_ptes)
+ self.maybe_plrus(m, r1, plru_victim)
+ self.maybe_tlb_plrus(m, r1, tlb_plru_victim)
+ self.cache_tag_read(m, r0_stall, req_index, cache_tag_set, cache_tags)
+ self.dcache_request(m, r0, ra, req_index, req_row, req_tag,
+ r0_valid, r1, cache_valids, replace_way,
+ use_forward1_next, use_forward2_next,
+ req_hit_way, plru_victim, rc_ok, perm_attr,
+ valid_ra, perm_ok, access_ok, req_op, req_go,
+ tlb_pte_way,
+ tlb_hit, tlb_hit_way, tlb_valid_way, cache_tag_set,
+ cancel_store, req_same_tag, r0_stall, early_req_row)
+ self.reservation_comb(m, cancel_store, set_rsrv, clear_rsrv,
+ r0_valid, r0, reservation)
+ self.reservation_reg(m, r0_valid, access_ok, set_rsrv, clear_rsrv,
+ reservation, r0)
+ self.writeback_control(m, r1, cache_out_row)
+ self.rams(m, r1, early_req_row, cache_out_row, replace_way)
+ self.dcache_fast_hit(m, req_op, r0_valid, r0, r1,
+ req_hit_way, req_index, req_tag, access_ok,
+ tlb_hit, tlb_hit_way, tlb_req_index)
+ self.dcache_slow(m, r1, use_forward1_next, use_forward2_next,
+ cache_valids, r0, replace_way,
+ req_hit_way, req_same_tag,
+ r0_valid, req_op, cache_tags, req_go, ra)
+ #self.dcache_log(m, r1, valid_ra, tlb_hit_way, stall_out)
+
+ return m
+
+def dcache_load(dut, addr, nc=0):
+ yield dut.d_in.load.eq(1)
+ yield dut.d_in.nc.eq(nc)
+ yield dut.d_in.addr.eq(addr)
+ yield dut.d_in.byte_sel.eq(~0)
+ yield dut.d_in.valid.eq(1)
+ yield
+ yield dut.d_in.valid.eq(0)
+ yield dut.d_in.byte_sel.eq(0)
+ yield
+ while not (yield dut.d_out.valid):
+ yield
+ data = yield dut.d_out.data
+ return data
+
+
+def dcache_store(dut, addr, data, nc=0):
+ yield dut.d_in.load.eq(0)
+ yield dut.d_in.nc.eq(nc)
+ yield dut.d_in.data.eq(data)
+ yield dut.d_in.byte_sel.eq(~0)
+ yield dut.d_in.addr.eq(addr)
+ yield dut.d_in.valid.eq(1)
+ yield
+ yield dut.d_in.valid.eq(0)
+ yield dut.d_in.byte_sel.eq(0)
+ yield
+ while not (yield dut.d_out.valid):
+ yield
+
+
+def dcache_random_sim(dut):
+
+ # start with stack of zeros
+ sim_mem = [0] * 512
+
+ # clear stuff
+ yield dut.d_in.valid.eq(0)
+ yield dut.d_in.load.eq(0)
+ yield dut.d_in.priv_mode.eq(1)
+ yield dut.d_in.nc.eq(0)
+ yield dut.d_in.addr.eq(0)
+ yield dut.d_in.data.eq(0)
+ yield dut.m_in.valid.eq(0)
+ yield dut.m_in.addr.eq(0)
+ yield dut.m_in.pte.eq(0)
+ # wait 4 * clk_period
+ yield
+ yield
+ yield
+ yield
+
+ print ()
+
+ for i in range(256):
+ addr = randint(0, 255)
+ data = randint(0, (1<<64)-1)
+ sim_mem[addr] = data
+ addr *= 8
+
+ print ("testing %x data %x" % (addr, data))
+
+ yield from dcache_load(dut, addr)
+ yield from dcache_store(dut, addr, data)
+
+ addr = randint(0, 255)
+ sim_data = sim_mem[addr]
+ addr *= 8
+
+ data = yield from dcache_load(dut, addr)
+ assert data == sim_data, \
+ "check %x data %x != %x" % (addr, data, sim_data)
+
+ for addr in range(256):
+ data = yield from dcache_load(dut, addr*8)
+ assert data == sim_mem[addr], \
+ "final check %x data %x != %x" % (addr*8, data, sim_mem[addr])
+
+def dcache_sim(dut):
+ # clear stuff
+ yield dut.d_in.valid.eq(0)
+ yield dut.d_in.load.eq(0)
+ yield dut.d_in.priv_mode.eq(1)
+ yield dut.d_in.nc.eq(0)
+ yield dut.d_in.addr.eq(0)
+ yield dut.d_in.data.eq(0)
+ yield dut.m_in.valid.eq(0)
+ yield dut.m_in.addr.eq(0)
+ yield dut.m_in.pte.eq(0)
+ # wait 4 * clk_period
+ yield
+ yield
+ yield
+ yield
+
+ # Cacheable read of address 4
+ data = yield from dcache_load(dut, 0x58)
+ addr = yield dut.d_in.addr
+ assert data == 0x0000001700000016, \
+ f"data @%x=%x expected 0x0000001700000016" % (addr, data)
+
+ # Cacheable read of address 20
+ data = yield from dcache_load(dut, 0x20)
+ addr = yield dut.d_in.addr
+ assert data == 0x0000000900000008, \
+ f"data @%x=%x expected 0x0000000900000008" % (addr, data)
+
+ # Cacheable read of address 30
+ data = yield from dcache_load(dut, 0x530)
+ addr = yield dut.d_in.addr
+ assert data == 0x0000014D0000014C, \
+ f"data @%x=%x expected 0000014D0000014C" % (addr, data)
+
+ # 2nd Cacheable read of address 30
+ data = yield from dcache_load(dut, 0x530)
+ addr = yield dut.d_in.addr
+ assert data == 0x0000014D0000014C, \
+ f"data @%x=%x expected 0000014D0000014C" % (addr, data)
+
+ # Non-cacheable read of address 100
+ data = yield from dcache_load(dut, 0x100, nc=1)
+ addr = yield dut.d_in.addr
+ assert data == 0x0000004100000040, \
+ f"data @%x=%x expected 0000004100000040" % (addr, data)
+
+ # Store at address 530
+ yield from dcache_store(dut, 0x530, 0x121)
+
+ # Store at address 30
+ yield from dcache_store(dut, 0x530, 0x12345678)
+
+ # 3nd Cacheable read of address 530
+ data = yield from dcache_load(dut, 0x530)
+ addr = yield dut.d_in.addr
+ assert data == 0x12345678, \
+ f"data @%x=%x expected 0x12345678" % (addr, data)
+
+ # 4th Cacheable read of address 20
+ data = yield from dcache_load(dut, 0x20)
+ addr = yield dut.d_in.addr
+ assert data == 0x0000000900000008, \
+ f"data @%x=%x expected 0x0000000900000008" % (addr, data)
+
+ yield
+ yield
+ yield
+ yield
+
+
+def test_dcache(mem, test_fn, test_name):
+ dut = DCache()
+
+ memory = Memory(width=64, depth=16*64, init=mem)
+ sram = SRAM(memory=memory, granularity=8)
+
+ m = Module()
+ m.submodules.dcache = dut
+ m.submodules.sram = sram
+
+ m.d.comb += sram.bus.cyc.eq(dut.wb_out.cyc)
+ m.d.comb += sram.bus.stb.eq(dut.wb_out.stb)
+ m.d.comb += sram.bus.we.eq(dut.wb_out.we)
+ m.d.comb += sram.bus.sel.eq(dut.wb_out.sel)
+ m.d.comb += sram.bus.adr.eq(dut.wb_out.adr)
+ m.d.comb += sram.bus.dat_w.eq(dut.wb_out.dat)
+
+ m.d.comb += dut.wb_in.ack.eq(sram.bus.ack)
+ m.d.comb += dut.wb_in.dat.eq(sram.bus.dat_r)
+
+ # nmigen Simulation
+ sim = Simulator(m)
+ sim.add_clock(1e-6)
+
+ sim.add_sync_process(wrap(test_fn(dut)))
+ with sim.write_vcd('test_dcache%s.vcd' % test_name):
+ sim.run()
+
+if __name__ == '__main__':
+ dut = DCache()
+ vl = rtlil.convert(dut, ports=[])
+ with open("test_dcache.il", "w") as f:
+ f.write(vl)
+
+ mem = []
+ for i in range(0,512):
+ mem.append((i*2)| ((i*2+1)<<32))
+
+ test_dcache(mem, dcache_sim, "")
+ test_dcache(None, dcache_random_sim, "random")
projects / soc.git / blobdiff