based on Anton Blanchard microwatt dcache.vhdl
+note that the microwatt dcache wishbone interface expects "stall".
+for simplicity at the moment this is hard-coded to cyc & ~ack.
+see WB4 spec, p84, section 5.2.1
+
+IMPORTANT: for store, the data is sampled the cycle AFTER the "valid"
+is raised. sigh
+
+Links:
+
+* https://libre-soc.org/3d_gpu/architecture/set_associative_cache.jpg
+* https://bugs.libre-soc.org/show_bug.cgi?id=469
+
"""
+import sys
+
+from nmutil.gtkw import write_gtkw
+
+sys.setrecursionlimit(1000000)
+
from enum import Enum, unique
from nmigen import Module, Signal, Elaboratable, Cat, Repl, Array, Const
-try:
- from nmigen.hdl.ast import Display
-except ImportError:
- def Display(*args):
- return []
+from nmutil.util import Display
+
+from copy import deepcopy
+from random import randint, seed
-from random import randint
+from nmigen_soc.wishbone.bus import Interface
from nmigen.cli import main
from nmutil.iocontrol import RecordObject
-from nmutil.util import wrap
from nmigen.utils import log2_int
from soc.experiment.mem_types import (LoadStore1ToDCacheType,
DCacheToLoadStore1Type,
WBIOMasterOut, WBIOSlaveOut)
from soc.experiment.cache_ram import CacheRam
-from soc.experiment.plru import PLRU
+#from soc.experiment.plru import PLRU
+from nmutil.plru import PLRU
# for test
-from nmigen_soc.wishbone.sram import SRAM
+from soc.bus.sram import SRAM
from nmigen import Memory
from nmigen.cli import rtlil
-if True:
- from nmigen.back.pysim import Simulator, Delay, Settle
-else:
- from nmigen.sim.cxxsim import Simulator, Delay, Settle
+
+# 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
# 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"
+# -- use consecutive indices to make a cache "line"
# --
# -- ROW_SIZE is the width in bytes of the BRAM
# -- (based on WB, so 64-bits)
# 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
.. --------| | TAG_BITS (45)
"""
print (layout)
-print ("Dcache TAG %d IDX %d ROW %d ROFF %d LOFF %d RLB %d" % \
+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))
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(INDEX_BITS, name="cachevalid_%d" % x) \
+ return Array(Signal(NUM_WAYS, name="cachevalid_%d" % x) \
for x in range(NUM_LINES))
def RowPerLineValidArray():
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 (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 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"
def TLBValidBitsArray():
- return Array(Signal(TLB_NUM_WAYS) for x in range(TLB_SET_SIZE))
+ 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) for x in range (TLB_NUM_WAYS))
+ 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) for x in range (TLB_SET_SIZE))
+ 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) for x in range(TLB_SET_SIZE))
+ 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) \
# PLRU output interface
def PLRUOut():
- return Array(Signal(WAY_BITS) for x in range(NUM_LINES))
+ 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) for x in range(TLB_SET_SIZE))
+ return Array(Signal(TLB_WAY_BITS, name="tlbplru_out%d" % x) \
+ for x in range(TLB_SET_SIZE))
# Helper functions to decode incoming requests
#
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;
def __init__(self, name=None):
super().__init__(name=name)
self.req = LoadStore1ToDCacheType(name="lsmem")
- self.tlbie = Signal()
- self.doall = Signal()
- self.tlbld = Signal()
+ self.tlbie = Signal() # indicates a tlbie request (from MMU)
+ self.doall = Signal() # with tlbie, indicates flush whole TLB
+ self.tlbld = Signal() # indicates a TLB load request (from MMU)
self.mmu_req = Signal() # indicates source of request
+ self.d_valid = Signal() # indicates req.data is valid now
class MemAccessRequest(RecordObject):
self.eatag = Signal(TLB_EA_TAG_BITS)
self.pte_data = Signal(TLB_PTE_BITS)
- self.dv = Signal(TLB_PTE_WAY_BITS)
+ self.dv = Signal(TLB_NUM_WAYS) # tlb_way_valids_t
- self.tb_out = Signal(TLB_TAG_WAY_BITS)
- self.pb_out = Signal(TLB_NUM_WAYS)
- self.db_out = Signal(TLB_PTE_WAY_BITS)
+ self.tb_out = Signal(TLB_TAG_WAY_BITS) # tlb_way_tags_t
+ self.db_out = Signal(TLB_NUM_WAYS) # tlb_way_valids_t
+ self.pb_out = Signal(TLB_PTE_WAY_BITS) # tlb_way_ptes_t
def elaborate(self, platform):
m = Module()
pteset = Signal(TLB_PTE_WAY_BITS)
tb_out, pb_out, db_out = self.tb_out, self.pb_out, self.db_out
+ comb += db_out.eq(self.dv)
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 += db_out.bit_select(self.tlb_hit_way, 1).eq(0)
comb += self.v_updated.eq(1)
with m.Elif(self.tlbwe):
return m
- def dcache_request(self, m, r0, ra, req_index, req_row, req_tag,
- r0_valid, r1, cache_valid_bits, 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):
- """Cache request parsing and hit detection
- """
class DCachePendingHit(Elaboratable):
def __init__(self, tlb_pte_way, tlb_valid_way, tlb_hit_way,
- cache_valid_idx, cache_tag_set,
+ cache_i_validdx, cache_tag_set,
req_addr,
hit_set):
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_i_validdx = cache_i_validdx
self.cache_tag_set = cache_tag_set
self.req_addr = req_addr
self.hit_set = hit_set
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_i_validdx = self.cache_i_validdx
cache_tag_set = self.cache_tag_set
req_addr = self.req_addr
tlb_hit_way = self.tlb_hit_way
# the TLB, and then decide later which match to use.
with m.If(virt_mode):
- for j in range(TLB_NUM_WAYS):
+ for j in range(TLB_NUM_WAYS): # tlb_num_way_t
s_tag = Signal(TAG_BITS, name="s_tag%d" % j)
s_hit = Signal()
s_pte = Signal(TLB_PTE_BITS)
s_pte[TLB_LG_PGSZ:REAL_ADDR_BITS]))
comb += s_tag.eq(get_tag(s_ra))
- for i in range(NUM_WAYS):
+ for i in range(NUM_WAYS): # way_t
is_tag_hit = Signal(name="is_tag_hit_%d_%d" % (j, i))
- comb += is_tag_hit.eq(go & cache_valid_idx[i] &
+ comb += is_tag_hit.eq(go & cache_i_validdx[i] &
(read_tag(i, cache_tag_set) == s_tag)
& tlb_valid_way[j])
with m.If(is_tag_hit):
with m.Else():
s_tag = Signal(TAG_BITS)
comb += s_tag.eq(get_tag(req_addr))
- for i in range(NUM_WAYS):
+ for i in range(NUM_WAYS): # way_t
is_tag_hit = Signal(name="is_tag_hit_%d" % i)
- comb += is_tag_hit.eq(go & cache_valid_idx[i] &
+ comb += is_tag_hit.eq(go & cache_i_validdx[i] &
(read_tag(i, cache_tag_set) == s_tag))
with m.If(is_tag_hit):
comb += hit_way.eq(i)
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
self.stall_out = Signal()
- self.wb_out = WBMasterOut()
- self.wb_in = WBSlaveOut()
+ # standard naming (wired to non-standard for compatibility)
+ self.bus = Interface(addr_width=32,
+ data_width=64,
+ granularity=8,
+ features={'stall'},
+ alignment=0,
+ name="dcache")
self.log_out = Signal(20)
sync += Display("request collision loadstore vs MMU")
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(1)
- 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)
+ comb += r.req.valid.eq(1)
+ comb += r.req.load.eq(~(m_in.tlbie | m_in.tlbld))# no invalidate
+ comb += r.req.dcbz.eq(0)
+ comb += r.req.nc.eq(0)
+ comb += r.req.reserve.eq(0)
+ comb += r.req.virt_mode.eq(0)
+ comb += r.req.priv_mode.eq(1)
+ comb += r.req.addr.eq(m_in.addr)
+ comb += r.req.data.eq(m_in.pte)
+ comb += r.req.byte_sel.eq(~0) # Const -1 sets all to 0b111....
+ comb += r.tlbie.eq(m_in.tlbie)
+ comb += r.doall.eq(m_in.doall)
+ comb += r.tlbld.eq(m_in.tlbld)
+ comb += r.mmu_req.eq(1)
+ m.d.sync += Display(" DCACHE req mmu addr %x pte %x ld %d",
+ m_in.addr, m_in.pte, r.req.load)
+
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)
+ comb += r.req.eq(d_in)
+ comb += r.req.data.eq(0)
+ comb += r.tlbie.eq(0)
+ comb += r.doall.eq(0)
+ comb += r.tlbld.eq(0)
+ comb += r.mmu_req.eq(0)
+ with m.If((~r1.full & ~d_in.hold) | ~r0_full):
+ sync += r0.eq(r)
+ sync += r0_full.eq(r.req.valid)
+ # Sample data the cycle after a request comes in from loadstore1.
+ # If another request has come in already then the data will get
+ # put directly into req.data below.
+ with m.If(r0.req.valid & ~r.req.valid & ~r0.d_valid &
+ ~r0.mmu_req):
+ sync += r0.req.data.eq(d_in.data)
+ sync += r0.d_valid.eq(1)
+ with m.If(d_in.valid):
+ m.d.sync += Display(" DCACHE req cache "
+ "virt %d addr %x data %x ld %d",
+ r.req.virt_mode, r.req.addr,
+ r.req.data, r.req.load)
def tlb_read(self, m, r0_stall, tlb_valid_way,
tlb_tag_way, tlb_pte_way, dtlb_valid_bits,
return
for i in range(TLB_SET_SIZE):
# TLB PLRU interface
- tlb_plru = PLRU(WAY_BITS)
+ 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.eq(r1.tlb_hit_way)
+ 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_pte_way, pte, tlb_hit, valid_ra, perm_attr, ra):
comb = m.d.comb
- sync = m.d.sync
hitway = Signal(TLB_WAY_BITS)
hit = Signal()
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)
+ is_tag_hit = Signal(name="is_tag_hit%d" % i)
+ tlb_tag = Signal(TLB_EA_TAG_BITS, name="tlb_tag%d" % i)
+ comb += tlb_tag.eq(read_tlb_tag(i, tlb_tag_way))
+ comb += is_tag_hit.eq(tlb_valid_way[i] & (tlb_tag == eatag))
with m.If(is_tag_hit):
comb += hitway.eq(i)
comb += hit.eq(1)
with m.If(tlb_hit):
comb += pte.eq(read_tlb_pte(hitway, tlb_pte_way))
- with m.Else():
- comb += pte.eq(0)
comb += valid_ra.eq(tlb_hit | ~r0.req.virt_mode)
+
with m.If(r0.req.virt_mode):
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.eq(extract_perm_attr(pte))
+ 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():
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.nocache.eq(0)
comb += perm_attr.rd_perm.eq(1)
comb += perm_attr.wr_perm.eq(1)
+ with m.If(valid_ra):
+ m.d.sync += Display("DCACHE virt mode %d hit %d ra %x pte %x",
+ r0.req.virt_mode, tlb_hit, ra, pte)
+ m.d.sync += Display(" perm ref=%d", perm_attr.reference)
+ m.d.sync += Display(" perm chg=%d", perm_attr.changed)
+ m.d.sync += Display(" perm noc=%d", perm_attr.nocache)
+ m.d.sync += Display(" perm prv=%d", perm_attr.priv)
+ m.d.sync += Display(" perm rdp=%d", perm_attr.rd_perm)
+ m.d.sync += Display(" perm wrp=%d", perm_attr.wr_perm)
+
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_valids = TLBValidBitsArray()
+
comb = m.d.comb
sync = m.d.sync
comb += plru_acc_en.eq(r1.cache_hit & (r1.hit_index == i))
comb += plru.acc_en.eq(plru_acc_en)
- comb += plru.acc.eq(r1.hit_way)
+ 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):
sync += cache_tag_set.eq(cache_tags[index])
def dcache_request(self, m, r0, ra, req_index, req_row, req_tag,
- r0_valid, r1, cache_valid_bits, replace_way,
+ 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,
"""
comb = m.d.comb
- sync = m.d.sync
m_in, d_in = self.m_in, self.d_in
is_hit = Signal()
nc = Signal()
hit_set = Array(Signal(name="hit_set_%d" % i) \
for i in range(TLB_NUM_WAYS))
- cache_valid_idx = Signal(INDEX_BITS)
+ cache_i_validdx = 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))
+ 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)
+
comb += go.eq(r0_valid & ~(r0.tlbie | r0.tlbld) & ~r1.ls_error)
- comb += cache_valid_idx.eq(cache_valid_bits[req_index])
+ comb += cache_i_validdx.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,
+ cache_i_validdx, cache_tag_set,
r0.req.addr,
hit_set)
# 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.
- valid = r1.rows_valid[req_row % ROW_PER_LINE]
- comb += is_hit.eq(~r0.req.load | valid)
+ 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)
# Whether to use forwarded data for a load or not
# work out whether we have permission for this access
# NB we don't yet implement AMR, thus no KUAP
comb += rc_ok.eq(perm_attr.reference
- & (r0.req.load | perm_attr.changed)
- )
- comb += perm_ok.eq((r0.req.priv_mode | ~perm_attr.priv) &
+ & (r0.req.load | perm_attr.changed))
+ 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)
comb += op.eq(Op.OP_NONE)
with m.If(go):
with m.If(~access_ok):
+ m.d.sync += Display("DCACHE access fail valid_ra=%d p=%d rc=%d",
+ valid_ra, perm_ok, rc_ok)
comb += op.eq(Op.OP_BAD)
with m.Elif(cancel_store):
+ m.d.sync += Display("DCACHE cancel store")
comb += op.eq(Op.OP_STCX_FAIL)
with m.Else():
+ m.d.sync += Display("DCACHE valid_ra=%d nc=%d ld=%d",
+ valid_ra, nc, r0.req.load)
comb += opsel.eq(Cat(is_hit, nc, r0.req.load))
with m.Switch(opsel):
with m.Case(0b101): comb += op.eq(Op.OP_LOAD_HIT)
"""Handle load-with-reservation and store-conditional instructions
"""
comb = m.d.comb
- sync = m.d.sync
with m.If(r0_valid & r0.req.reserve):
# XXX generate alignment interrupt if address
# is not aligned XXX or if r0.req.nc = '1'
with m.If(r0.req.load):
- comb += set_rsrv.eq(1) # load with reservation
+ comb += set_rsrv.eq(r0.req.atomic_last) # load with reservation
with m.Else():
- comb += clear_rsrv.eq(1) # store conditional
- with m.If(~reservation.valid |
+ comb += clear_rsrv.eq(r0.req.atomic_last) # store conditional
+ with m.If((~reservation.valid) |
(r0.req.addr[LINE_OFF_BITS:64] != reservation.addr)):
comb += cancel_store.eq(1)
sync += reservation.valid.eq(1)
sync += reservation.addr.eq(r0.req.addr[LINE_OFF_BITS:64])
- def writeback_control(self, m, r1, cache_out):
+ def writeback_control(self, m, r1, cache_out_row):
"""Return data for loads & completion control logic
"""
comb = m.d.comb
with m.Else():
comb += data_fwd.eq(r1.forward_data2)
- comb += data_out.eq(cache_out[r1.hit_way])
+ comb += data_out.eq(cache_out_row)
for i in range(8):
with m.If(r1.forward_sel[i]):
# error cases complete without stalling
with m.If(r1.ls_error):
- sync += Display("completing ld/st with error")
+ with m.If(r1.dcbz):
+ sync += Display("completing dcbz with error")
+ with m.Else():
+ sync += Display("completing ld/st with error")
# Slow ops (load miss, NC, stores)
with m.If(r1.slow_valid):
- sync += Display("completing store or load miss data=%x",
- data_out)
+ sync += Display("completing store or load miss adr=%x data=%x",
+ r1.req.real_addr, data_out)
with m.Else():
# Request came from MMU
# Slow ops (i.e. load miss)
with m.If(r1.slow_valid):
- sync += Display("completing MMU load miss, data=%x",
- m_out.data)
+ sync += Display("completing MMU load miss, adr=%x data=%x",
+ r1.req.real_addr, m_out.data)
- def rams(self, m, r1, early_req_row, cache_out, replace_way):
+ 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
account by using 1-cycle delayed signals for load hits.
"""
comb = m.d.comb
- wb_in = self.wb_in
+ bus = self.bus
for i in range(NUM_WAYS):
do_read = Signal(name="do_rd%d" % i)
- rd_addr = Signal(ROW_BITS)
+ rd_addr = Signal(ROW_BITS, name="rd_addr_%d" % i)
do_write = Signal(name="do_wr%d" % i)
- wr_addr = Signal(ROW_BITS)
- wr_data = Signal(WB_DATA_BITS)
+ wr_addr = Signal(ROW_BITS, name="wr_addr_%d" % i)
+ wr_data = Signal(WB_DATA_BITS, name="din_%d" % i)
wr_sel = Signal(ROW_SIZE)
wr_sel_m = Signal(ROW_SIZE)
- _d_out = Signal(WB_DATA_BITS, name="dout_%d" % i)
+ _d_out = Signal(WB_DATA_BITS, name="dout_%d" % i) # cache_row_t
- way = CacheRam(ROW_BITS, WB_DATA_BITS, True)
+ way = CacheRam(ROW_BITS, WB_DATA_BITS, ADD_BUF=True, ram_num=i)
setattr(m.submodules, "cacheram_%d" % i, way)
comb += way.rd_en.eq(do_read)
# Cache hit reads
comb += do_read.eq(1)
- comb += rd_addr.eq(early_req_row[:ROW_BITS])
- comb += cache_out[i].eq(_d_out)
+ comb += rd_addr.eq(early_req_row)
+ with m.If(r1.hit_way == i):
+ comb += cache_out_row.eq(_d_out)
# Write mux:
#
with m.If(r1.dcbz):
comb += wr_data.eq(0)
with m.Else():
- comb += wr_data.eq(wb_in.dat)
+ comb += wr_data.eq(bus.dat_r)
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)
+ with m.If((r1.state == State.RELOAD_WAIT_ACK)
+ & bus.ack & (replace_way == i)):
+ comb += do_write.eq(1)
# Mask write selects with do_write since BRAM
# doesn't have a global write-enable
sync += r1.cache_hit.eq(0)
with m.If(req_op == Op.OP_BAD):
- # Display(f"Signalling ld/st error valid_ra={valid_ra}"
- # f"rc_ok={rc_ok} perm_ok={perm_ok}"
+ sync += Display("Signalling ld/st error "
+ "ls_error=%i mmu_error=%i cache_paradox=%i",
+ ~r0.mmu_req,r0.mmu_req,access_ok)
sync += r1.ls_error.eq(~r0.mmu_req)
sync += r1.mmu_error.eq(r0.mmu_req)
sync += r1.cache_paradox.eq(access_ok)
- with m.Else():
- sync += r1.ls_error.eq(0)
- sync += r1.mmu_error.eq(0)
- sync += r1.cache_paradox.eq(0)
+ with m.Else():
+ sync += r1.ls_error.eq(0)
+ sync += r1.mmu_error.eq(0)
+ sync += r1.cache_paradox.eq(0)
with m.If(req_op == Op.OP_STCX_FAIL):
- r1.stcx_fail.eq(1)
+ sync += r1.stcx_fail.eq(1)
with m.Else():
sync += r1.stcx_fail.eq(0)
# All wishbone requests generation is done here.
# This machine operates at stage 1.
def dcache_slow(self, m, r1, use_forward1_next, use_forward2_next,
- cache_valid_bits, r0, replace_way,
+ 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
+ bus = self.bus
+ d_in = self.d_in
req = MemAccessRequest("mreq_ds")
- acks = Signal(3)
- adjust_acks = Signal(3)
req_row = Signal(ROW_BITS)
req_idx = Signal(INDEX_BITS)
with m.If(r1.dcbz):
sync += r1.forward_data1.eq(0)
with m.Else():
- sync += r1.forward_data1.eq(wb_in.dat)
+ sync += r1.forward_data1.eq(bus.dat_r)
sync += r1.forward_sel1.eq(~0) # all 1s
sync += r1.forward_way1.eq(replace_way)
sync += r1.forward_row1.eq(r1.store_row)
# 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((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():
with m.If(i == replace_way):
ct = Signal(TAG_RAM_WIDTH)
comb += ct.eq(cache_tags[r1.store_index])
+ """
+TODO: check this
+cache_tags(r1.store_index)((i + 1) * TAG_WIDTH - 1 downto i * TAG_WIDTH) <=
+ (TAG_WIDTH - 1 downto TAG_BITS => '0') & r1.reload_tag;
+ """
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)
comb += req.dcbz.eq(r0.req.dcbz)
comb += req.real_addr.eq(ra)
- with m.If(~r0.req.dcbz):
+ with m.If(r0.req.dcbz):
+ # force data to 0 for dcbz
+ comb += req.data.eq(0)
+ with m.Elif(r0.d_valid):
comb += req.data.eq(r0.req.data)
with m.Else():
- comb += req.data.eq(0)
+ comb += req.data.eq(d_in.data)
# Select all bytes for dcbz
# and for cacheable loads
with m.Switch(r1.state):
with m.Case(State.IDLE):
- sync += r1.wb.adr.eq(req.real_addr)
+ sync += r1.wb.adr.eq(req.real_addr[ROW_LINE_BITS:])
sync += r1.wb.sel.eq(req.byte_sel)
sync += r1.wb.dat.eq(req.data)
sync += r1.dcbz.eq(req.dcbz)
# 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.end_row_ix.eq(get_row_of_line(req_row)-1)
sync += r1.reload_tag.eq(req_tag)
sync += r1.req.same_tag.eq(1)
# 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.wb.adr, r1.end_row_ix)):
+ # If we are still sending requests, was one accepted?
+ with m.If((~bus.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.
+ # sigh - reconstruct wb adr with 3 extra 0s at front
+ wb_adr = Cat(Const(0, ROW_OFF_BITS), r1.wb.adr)
+ with m.If(is_last_row_addr(wb_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
- rarange = Signal(LINE_OFF_BITS-ROW_OFF_BITS)
- comb += rarange.eq(r1.wb.adr[ROW_OFF_BITS:LINE_OFF_BITS]+1)
- sync += r1.wb.adr[ROW_OFF_BITS:LINE_OFF_BITS].eq(rarange)
+ row = Signal(LINE_OFF_BITS-ROW_OFF_BITS)
+ comb += row.eq(r1.wb.adr)
+ sync += r1.wb.adr[:LINE_OFF_BITS-ROW_OFF_BITS].eq(row+1)
# Incoming acks processing
- sync += r1.forward_valid1.eq(wb_in.ack)
- with m.If(wb_in.ack):
- sync += r1.rows_valid[r1.store_row % ROW_PER_LINE].eq(1)
+ sync += r1.forward_valid1.eq(bus.ack)
+ with m.If(bus.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 &
+ with m.If(req.valid & 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.store_row == get_row(req.real_addr))):
sync += r1.full.eq(0)
sync += r1.slow_valid.eq(1)
with m.If(~r1.mmu_req):
# Cache line is now valid
cv = Signal(INDEX_BITS)
- comb += cv.eq(cache_valid_bits[r1.store_index])
+ comb += cv.eq(cache_valids[r1.store_index])
comb += cv.bit_select(r1.store_way, 1).eq(1)
- sync += cache_valid_bits[r1.store_index].eq(cv)
+ sync += cache_valids[r1.store_index].eq(cv)
+
sync += r1.state.eq(State.IDLE)
+ sync += Display("cache valid set %x "
+ "idx %d way %d",
+ cv, r1.store_index, r1.store_way)
# 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()
+ acks = Signal(3)
+ adjust_acks = Signal(3)
+
comb += st_stbs_done.eq(~r1.wb.stb)
comb += acks.eq(r1.acks_pending)
sync += r1.acks_pending.eq(adjust_acks)
# Clear stb when slave accepted request
- with m.If(~wb_in.stall):
+ with m.If(~bus.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.wb.adr[0:SET_SIZE_BITS].eq(ra)
+ _ra = req.real_addr[ROW_LINE_BITS:SET_SIZE_BITS]
+ sync += r1.wb.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 &
+ with m.If((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(1)
# Got ack ? See if complete.
- with m.If(wb_in.ack):
+ with m.If(bus.ack):
with m.If(st_stbs_done & (adjust_acks == 1)):
sync += r1.state.eq(State.IDLE)
sync += r1.wb.cyc.eq(0)
with m.Case(State.NC_LOAD_WAIT_ACK):
# Clear stb when slave accepted request
- with m.If(~wb_in.stall):
+ with m.If(~bus.stall):
sync += r1.wb.stb.eq(0)
# Got ack ? complete.
- with m.If(wb_in.ack):
+ with m.If(bus.ack):
sync += r1.state.eq(State.IDLE)
sync += r1.full.eq(0)
sync += r1.slow_valid.eq(1)
def dcache_log(self, m, r1, valid_ra, tlb_hit_way, stall_out):
sync = m.d.sync
- d_out, wb_in, log_out = self.d_out, self.wb_in, self.log_out
+ d_out, bus, log_out = self.d_out, self.bus, self.log_out
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.wb.adr[3:6]))
+ r1.wb.cyc, r1.wb.stb, bus.ack, bus.stall,
+ r1.real_adr[3:6]))
def elaborate(self, platform):
m = Module()
comb = m.d.comb
+ d_in = self.d_in
# 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";
use_forward1_next = Signal()
use_forward2_next = Signal()
- cache_out = CacheRamOut()
+ cache_out_row = Signal(WB_DATA_BITS)
plru_victim = PLRUOut()
replace_way = Signal(WAY_BITS)
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 += r0_stall.eq(r0_full & (r1.full | d_in.hold))
+ comb += r0_valid.eq(r0_full & ~r1.full & ~d_in.hold)
comb += self.stall_out.eq(r0_stall)
+
+ # deal with litex not doing wishbone pipeline mode
+ # XXX in wrong way. FIFOs are needed in the SRAM test
+ # so that stb/ack match up. same thing done in icache.py
+ comb += self.bus.stall.eq(self.bus.cyc & ~self.bus.ack)
+
# Wire up wishbone request latch out of stage 1
- comb += self.wb_out.eq(r1.wb)
+ comb += self.bus.we.eq(r1.wb.we)
+ comb += self.bus.adr.eq(r1.wb.adr)
+ comb += self.bus.sel.eq(r1.wb.sel)
+ comb += self.bus.stb.eq(r1.wb.stb)
+ comb += self.bus.dat_w.eq(r1.wb.dat)
+ comb += self.bus.cyc.eq(r1.wb.cyc)
# call sub-functions putting everything together, using shared
# signals established above
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_valid_bits, replace_way,
+ 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,
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)
- self.rams(m, r1, early_req_row, cache_out, replace_way)
+ 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_valid_bits, r0, replace_way,
+ 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(8):
- 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, 0x4)
- addr = yield dut.d_in.addr
- assert data == 0x0000000100000000, \
- f"data @%x=%x expected 0x0000000100000000" % (addr, data)
-
- # Cacheable read of address 20
- data = yield from dcache_load(dut, 0x20)
- addr = yield dut.d_in.addr
- assert data == 0x0000000100000000, \
- f"data @%x=%x expected 0x0000000100000000" % (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 30
- data = yield from dcache_load(dut, 0x20)
- addr = yield dut.d_in.addr
- assert data == 0x12345678, \
- f"data @%x=%x expected 0x12345678" % (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[3:])
- 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