* https://bugs.libre-soc.org/show_bug.cgi?id=216
* https://libre-soc.org/3d_gpu/architecture/memory_and_cache/
+* https://bugs.libre-soc.org/show_bug.cgi?id=465 - exception handling
"""
from nmutil.latch import SRLatch, latchregister
from nmutil.util import rising_edge
-from soc.decoder.power_decoder2 import Data
+from openpower.decoder.power_decoder2 import Data
+from openpower.decoder.power_enums import MSRSpec
from soc.scoreboard.addr_match import LenExpand
+from soc.experiment.mem_types import LDSTException
# for testing purposes
from soc.experiment.testmem import TestMemory
+#from soc.scoreboard.addr_split import LDSTSplitter
+from nmutil.util import Display
import unittest
for the L0 Cache/Buffer to have an additional address latch
(because the LDSTCompUnit already has it)
- * addr_ok_o (or addr_exc_o) must be waited for. these will
+ * addr_ok_o (or exception.happened) must be waited for. these will
be asserted *only* for one cycle and one cycle only.
- * addr_exc_o will be asserted if there is no chance that the
+ * exception.happened will be asserted if there is no chance that the
memory request may be fulfilled.
- busy_o is deasserted on the same cycle as addr_exc_o is asserted.
+ busy_o is deasserted on the same cycle as exception.happened is asserted.
* conversely: addr_ok_o must *ONLY* be asserted if there is a
HUNDRED PERCENT guarantee that the memory request will be
busy_o is deasserted on the cycle AFTER st.ok is asserted.
"""
- def __init__(self, name=None, regwid=64, addrwid=48):
+ def __init__(self, name=None, regwid=64, addrwid=64):
self._regwid = regwid
self._addrwid = addrwid
RecordObject.__init__(self, name=name)
- # distinguish op type (ld/st)
- self.is_ld_i = Signal(reset_less=True)
- self.is_st_i = Signal(reset_less=True)
+ # distinguish op type (ld/st/dcbz/nc)
+ self.is_ld_i = Signal(reset_less=True)
+ self.is_st_i = Signal(reset_less=True)
+ self.is_dcbz_i = Signal(reset_less=True) # cache-line zeroing
+ self.is_nc = Signal() # no cacheing
# LD/ST data length (TODO: other things may be needed)
self.data_len = Signal(4, reset_less=True)
+ # atomic reservation (LR/SC - ldarx / stdcx etc.)
+ self.reserve = Signal(reset_less=True)
+
# common signals
self.busy_o = Signal(reset_less=True) # do not use if busy
self.go_die_i = Signal(reset_less=True) # back to reset
self.addr = Data(addrwid, "addr_i") # addr/addr-ok
# addr is valid (TLB, L1 etc.)
self.addr_ok_o = Signal(reset_less=True)
- self.addr_exc_o = Signal(reset_less=True) # TODO, "type" of exception
+ self.exc_o = LDSTException("exc")
# LD/ST
self.ld = Data(regwid, "ld_data_o") # ok to be set by L0 Cache/Buf
self.st = Data(regwid, "st_data_i") # ok to be set by CompUnit
+ self.store_done = Data(1, "store_done_o") # store has been actioned
+
+ #only priv_mode = not msr_pr is used currently
+ # TODO: connect signals
+ self.virt_mode = Signal() # ctrl.msr(MSR_DR);
+ self.priv_mode = Signal() # not ctrl.msr(MSR_PR);
+ self.mode_32bit = Signal() # not ctrl.msr(MSR_SF);
+
+ # dcache
+ self.ldst_error = Signal()
+ ## Signalling ld/st error - NC cache hit, TLB miss, prot/RC failure
+ self.cache_paradox = Signal()
def connect_port(self, inport):
print("connect_port", self, inport)
return [self.is_ld_i.eq(inport.is_ld_i),
self.is_st_i.eq(inport.is_st_i),
+ self.is_nc.eq(inport.is_nc),
+ self.is_dcbz_i.eq(inport.is_dcbz_i),
self.data_len.eq(inport.data_len),
+ self.reserve.eq(inport.reserve),
self.go_die_i.eq(inport.go_die_i),
self.addr.data.eq(inport.addr.data),
self.addr.ok.eq(inport.addr.ok),
self.st.eq(inport.st),
+ self.virt_mode.eq(inport.virt_mode),
+ self.priv_mode.eq(inport.priv_mode),
+ self.mode_32bit.eq(inport.mode_32bit),
inport.ld.eq(self.ld),
inport.busy_o.eq(self.busy_o),
inport.addr_ok_o.eq(self.addr_ok_o),
- inport.addr_exc_o.eq(self.addr_exc_o),
+ inport.exc_o.eq(self.exc_o),
+ inport.store_done.eq(self.store_done),
+ inport.ldst_error.eq(self.ldst_error),
+ inport.cache_paradox.eq(self.cache_paradox)
]
def connect_port(self, inport):
return self.pi.connect_port(inport)
- def set_wr_addr(self, m, addr, mask): pass
- def set_rd_addr(self, m, addr, mask): pass
+ def set_wr_addr(self, m, addr, mask, misalign, msr, is_dcbz, is_nc): pass
+ def set_rd_addr(self, m, addr, mask, misalign, msr, is_nc): pass
def set_wr_data(self, m, data, wen): pass
def get_rd_data(self, m): pass
comb += lds.eq(pi.is_ld_i) # ld-req signals
comb += sts.eq(pi.is_st_i) # st-req signals
+ # TODO: construct an MSRspec here and pass it over in
+ # self.set_rd_addr and set_wr_addr below rather than just pr
+ pr = ~pi.priv_mode
+ dr = pi.virt_mode
+ sf = ~pi.mode_32bit
+ msr = MSRSpec(pr=pr, dr=dr, sf=sf)
+
# detect busy "edge"
busy_delay = Signal()
busy_edge = Signal()
sync += busy_delay.eq(pi.busy_o)
comb += busy_edge.eq(pi.busy_o & ~busy_delay)
+ # misalignment detection: bits at end of lenexpand are set.
+ # when using the L0CacheBuffer "data expander" which splits requests
+ # into *two* PortInterfaces, this acts as a "safety check".
+ misalign = Signal()
+ comb += misalign.eq(lenexp.lexp_o[8:].bool())
+
# activate mode: only on "edge"
comb += ld_active.s.eq(rising_edge(m, lds)) # activate LD mode
comb += st_active.s.eq(rising_edge(m, sts)) # activate ST mode
# LD/ST requested activates "busy" (only if not already busy)
with m.If(self.pi.is_ld_i | self.pi.is_st_i):
comb += busy_l.s.eq(~busy_delay)
+ with m.If(self.pi.exc_o.happened):
+ sync += Display("fast exception")
# if now in "LD" mode: wait for addr_ok, then send the address out
# to memory, acknowledge address, and send out LD data
comb += lenexp.len_i.eq(pi.data_len)
comb += lenexp.addr_i.eq(lsbaddr)
with m.If(pi.addr.ok & adrok_l.qn):
- self.set_rd_addr(m, pi.addr.data, lenexp.lexp_o)
+ self.set_rd_addr(m, pi.addr.data, lenexp.lexp_o, misalign,
+ msr, pi.is_nc)
comb += pi.addr_ok_o.eq(1) # acknowledge addr ok
sync += adrok_l.s.eq(1) # and pull "ack" latch
comb += lenexp.len_i.eq(pi.data_len)
comb += lenexp.addr_i.eq(lsbaddr)
with m.If(pi.addr.ok):
- self.set_wr_addr(m, pi.addr.data, lenexp.lexp_o)
- with m.If(adrok_l.qn):
+ self.set_wr_addr(m, pi.addr.data, lenexp.lexp_o, misalign, msr,
+ pi.is_dcbz_i, pi.is_nc)
+ with m.If(adrok_l.qn & self.pi.exc_o.happened==0):
comb += pi.addr_ok_o.eq(1) # acknowledge addr ok
sync += adrok_l.s.eq(1) # and pull "ack" latch
comb += reset_l.s.eq(ldok) # reset mode after 1 cycle
# for ST mode, when addr has been "ok'd", wait for incoming "ST ok"
+ sync += st_done.s.eq(0) # store done trigger
with m.If(st_active.q & pi.st.ok):
# shift data up before storing. lenexp *bit* version of mask is
# passed straight through as byte-level "write-enable" lines.
- stdata = Signal(self.regwid, reset_less=True)
+ stdata = Signal(self.regwid*2, reset_less=True)
comb += stdata.eq(pi.st.data << (lenexp.addr_i*8))
# TODO: replace with link to LoadStoreUnitInterface.x_store_data
# and also handle the ready/stall/busy protocol
stok = self.set_wr_data(m, stdata, lenexp.lexp_o)
- sync += st_done.s.eq(1) # store done trigger
+ sync += st_done.s.eq(~self.pi.exc_o.happened) # store done trigger
with m.If(st_done.q):
comb += reset_l.s.eq(stok) # reset mode after 1 cycle
# after waiting one cycle (reset_l is "sync" mode), reset the port
with m.If(reset_l.q):
- comb += ld_active.r.eq(1) # leave the ST active for 1 cycle
+ comb += ld_active.r.eq(1) # leave the LD active for 1 cycle
comb += st_active.r.eq(1) # leave the ST active for 1 cycle
comb += reset_l.r.eq(1) # clear reset
comb += adrok_l.r.eq(1) # address reset
comb += st_done.r.eq(1) # store done reset
- # monitor for an exception or the completion of LD.
- with m.If(self.pi.addr_exc_o):
+ # monitor for an exception, clear busy immediately
+ with m.If(self.pi.exc_o.happened):
comb += busy_l.r.eq(1)
+ comb += reset_l.s.eq(1) # also reset whole unit
# however ST needs one cycle before busy is reset
#with m.If(self.pi.st.ok | self.pi.ld.ok):
comb += busy_l.r.eq(1)
# busy latch outputs to interface
- comb += pi.busy_o.eq(busy_l.q)
+ if hasattr(self, "external_busy"):
+ # when there is an extra (external) busy, include that here.
+ # this is used e.g. in LoadStore1 when an instruction fault
+ # is being processed (instr_fault) and stops Load/Store requests
+ # from being made until it's done
+ comb += pi.busy_o.eq(busy_l.q | self.external_busy(m))
+ else:
+ comb += pi.busy_o.eq(busy_l.q)
return m
# hard-code memory addressing width to 6 bits
self.mem = TestMemory(regwid, 5, granularity=regwid//8, init=False)
- def set_wr_addr(self, m, addr, mask):
- lsbaddr, msbaddr = self.splitaddr(addr)
- m.d.comb += self.mem.wrport.addr.eq(msbaddr)
-
- def set_rd_addr(self, m, addr, mask):
- lsbaddr, msbaddr = self.splitaddr(addr)
- m.d.comb += self.mem.rdport.addr.eq(msbaddr)
-
- def set_wr_data(self, m, data, wen):
- m.d.comb += self.mem.wrport.data.eq(data) # write st to mem
- m.d.comb += self.mem.wrport.en.eq(wen) # enable writes
- return Const(1, 1)
-
- def get_rd_data(self, m):
- return self.mem.rdport.data, Const(1, 1)
-
- def elaborate(self, platform):
- m = super().elaborate(platform)
-
- # add TestMemory as submodule
- m.submodules.mem = self.mem
-
- return m
-
- def ports(self):
- yield from super().ports()
- # TODO: memory ports
-
-class TestCachedMemoryPortInterface(PortInterfaceBase):
- """TestCacheMemoryPortInterface
-
- This is a test class for simple verification of LDSTSplitter
- conforming to PortInterface,
- """
-
- def __init__(self, regwid=64, addrwid=4):
- super().__init__(regwid, addrwid)
- # hard-code memory addressing width to 6 bits
- self.mem = None
-
- def set_wr_addr(self, m, addr, mask):
+ def set_wr_addr(self, m, addr, mask, misalign, msr, is_dcbz, is_nc):
lsbaddr, msbaddr = self.splitaddr(addr)
m.d.comb += self.mem.wrport.addr.eq(msbaddr)
- def set_rd_addr(self, m, addr, mask):
+ def set_rd_addr(self, m, addr, mask, misalign, msr, is_nc):
lsbaddr, msbaddr = self.splitaddr(addr)
m.d.comb += self.mem.rdport.addr.eq(msbaddr)
projects / soc.git / blobdiff