+"""
+Based on microwatt mmu.vhdl
+
+* https://bugs.libre-soc.org/show_bug.cgi?id=491
+* https://bugs.libre-soc.org/show_bug.cgi?id=450
+"""
+
from nmigen import Elaboratable, Module, Signal, Shape, unsigned, Cat, Mux
-from nmigen import Record
+from nmigen import Record, Memory
from nmigen import Const
from soc.fu.mmu.pipe_data import MMUInputData, MMUOutputData, MMUPipeSpec
from nmutil.singlepipe import ControlBase
from nmutil.util import rising_edge
from soc.experiment.mmu import MMU
-from soc.experiment.dcache import DCache
from openpower.consts import MSR
from openpower.decoder.power_fields import DecodeFields
from openpower.decoder.power_fieldsn import SignalBitRange
from openpower.decoder.power_decoder2 import decode_spr_num
-from openpower.decoder.power_enums import MicrOp, XER_bits
-
-from soc.experiment.pimem import PortInterface
-from soc.experiment.pimem import PortInterfaceBase
+from openpower.decoder.power_enums import MicrOp
-from soc.experiment.mem_types import LoadStore1ToDCacheType, LoadStore1ToMMUType
-from soc.experiment.mem_types import DCacheToLoadStore1Type, MMUToLoadStore1Type
+from soc.experiment.mem_types import LoadStore1ToMMUType
+from soc.experiment.mem_types import MMUToLoadStore1Type
-from soc.minerva.wishbone import make_wb_layout
-
-
-# glue logic for microwatt mmu and dcache
-class LoadStore1(PortInterfaceBase):
- def __init__(self, pspec):
- regwid = pspec.reg_wid
- addrwid = pspec.addr_wid
-
- super().__init__(regwid, addrwid)
- self.dcache = DCache()
- self.d_in = self.dcache.d_in
- self.d_out = self.dcache.d_out
- self.l_in = LoadStore1ToMMUType()
- self.l_out = MMUToLoadStore1Type()
- # for debugging with gtkwave only
- self.debug1 = Signal()
- self.debug2 = Signal()
- # TODO microwatt
- self.mmureq = Signal()
- self.derror = Signal()
-
- # TODO, convert dcache wb_in/wb_out to "standard" nmigen Wishbone bus
- self.dbus = Record(make_wb_layout(pspec))
-
- def set_wr_addr(self, m, addr, mask):
- #m.d.comb += self.d_in.valid.eq(1)
- #m.d.comb += self.l_in.valid.eq(1)
- #m.d.comb += self.d_in.load.eq(0)
- #m.d.comb += self.l_in.load.eq(0)
- # set phys addr on both units
- m.d.comb += self.d_in.addr.eq(addr)
- m.d.comb += self.l_in.addr.eq(addr)
- # TODO set mask
- return None
-
- def set_rd_addr(self, m, addr, mask):
- m.d.comb += self.d_in.valid.eq(1)
- m.d.comb += self.l_in.valid.eq(1)
- m.d.comb += self.d_in.load.eq(1)
- m.d.comb += self.l_in.load.eq(1)
- m.d.comb += self.d_in.addr.eq(addr)
- m.d.comb += self.l_in.addr.eq(addr)
- m.d.comb += self.debug1.eq(1)
- # m.d.comb += self.debug2.eq(1)
- return None #FIXME return value
-
- def set_wr_data(self, m, data, wen):
- m.d.comb += self.d_in.data.eq(data)
- # TODO set wen
- st_ok = Const(1, 1)
- return st_ok
-
- def get_rd_data(self, m):
- ld_ok = self.d_out.valid # indicates read data is valid
- data = self.d_out.data # actual read data
- return data, ld_ok
-
- """
- if d_in.error = '1' then
- if d_in.cache_paradox = '1' then
- -- signal an interrupt straight away
- exception := '1';
- dsisr(63 - 38) := not r2.req.load;
- -- XXX there is no architected bit for this
- -- (probably should be a machine check in fact)
- dsisr(63 - 35) := d_in.cache_paradox;
- else
- -- Look up the translation for TLB miss
- -- and also for permission error and RC error
- -- in case the PTE has been updated.
- mmureq := '1';
- v.state := MMU_LOOKUP;
- v.stage1_en := '0';
- end if;
- end if;
- """
-
- def elaborate(self, platform):
- m = super().elaborate(platform)
- comb = m.d.comb
-
- # create dcache module
- m.submodules.dcache = dcache = self.dcache
-
- # temp vars
- d_out, l_out, dbus = self.d_out, self.l_out, self.dbus
-
- with m.If(d_out.error):
- with m.If(d_out.cache_paradox):
- comb += self.derror.eq(1)
- # dsisr(63 - 38) := not r2.req.load;
- # -- XXX there is no architected bit for this
- # -- (probably should be a machine check in fact)
- # dsisr(63 - 35) := d_in.cache_paradox;
- with m.Else():
- # Look up the translation for TLB miss
- # and also for permission error and RC error
- # in case the PTE has been updated.
- comb += self.mmureq.eq(1)
- # v.state := MMU_LOOKUP;
- # v.stage1_en := '0';
-
- exc = self.pi.exception_o
-
- #happened, alignment, instr_fault, invalid,
- comb += exc.happened.eq(d_out.error | l_out.err)
- comb += exc.invalid.eq(l_out.invalid)
-
- #badtree, perm_error, rc_error, segment_fault
- comb += exc.badtree.eq(l_out.badtree)
- comb += exc.perm_error.eq(l_out.perm_error)
- comb += exc.rc_error.eq(l_out.rc_error)
- comb += exc.segment_fault.eq(l_out.segerr)
-
- # TODO connect those signals somewhere
- #print(d_out.valid) -> no error
- #print(d_out.store_done) -> no error
- #print(d_out.cache_paradox) -> ?
- #print(l_out.done) -> no error
-
- # TODO some exceptions set SPRs
-
- # TODO, connect dcache wb_in/wb_out to "standard" nmigen Wishbone bus
- comb += dbus.adr.eq(dcache.wb_out.adr)
- comb += dbus.dat_w.eq(dcache.wb_out.dat)
- comb += dbus.sel.eq(dcache.wb_out.sel)
- comb += dbus.cyc.eq(dcache.wb_out.cyc)
- comb += dbus.stb.eq(dcache.wb_out.stb)
- comb += dbus.we.eq(dcache.wb_out.we)
-
- comb += dcache.wb_in.dat.eq(dbus.dat_r)
- comb += dcache.wb_in.ack.eq(dbus.ack)
- if hasattr(dbus, "stall"):
- comb += dcache.wb_in.stall.eq(dbus.stall)
-
- return m
-
- def ports(self):
- yield from super().ports()
- # TODO: memory ports
+from soc.fu.ldst.loadstore import LoadStore1, TestSRAMLoadStore1
+from nmutil.util import Display
class FSMMMUStage(ControlBase):
FSM-based MMU: must call set_ldst_interface and pass in an instance
of a LoadStore1. this to comply with the ConfigMemoryPortInterface API
+
+ this Function Unit is extremely unusual in that it actually stores a
+ "thing" rather than "processes inputs and produces outputs". hence
+ why it has to be a FSM. linking up LD/ST however is going to have
+ to be done back in Issuer (or Core). sorted: call set_ldst_interface
"""
def __init__(self, pspec):
super().__init__()
self.pspec = pspec
# set up p/n data
- self.p.data_i = MMUInputData(pspec)
- self.n.data_o = MMUOutputData(pspec)
-
- # this Function Unit is extremely unusual in that it actually stores a
- # "thing" rather than "processes inputs and produces outputs". hence
- # why it has to be a FSM. linking up LD/ST however is going to have
- # to be done back in Issuer (or Core)
+ self.p.i_data = MMUInputData(pspec)
+ self.n.o_data = MMUOutputData(pspec)
+ self.exc_o = self.n.o_data.exception # AllFunctionUnits needs this
self.mmu = MMU()
- # make life a bit easier in Core XXX mustn't really do this,
- # pspec is designed for config variables, rather than passing
- # things around. have to think about it, design a way to do
- # it that makes "sense"
- # comment out for now self.pspec.mmu = self.mmu
- # comment out for now self.pspec.dcache = self.dcache
-
# debugging output for gtkw
self.debug0 = Signal(4)
- self.debug1 = Signal()
- #self.debug2 = Signal(64)
- #self.debug3 = Signal(64)
self.illegal = Signal()
# for SPR field number access
- i = self.p.data_i
+ i = self.p.i_data
self.fields = DecodeFields(SignalBitRange, [i.ctx.op.insn])
self.fields.create_specs()
# incoming PortInterface
self.ldst = ldst
self.dcache = self.ldst.dcache
+ self.icache = self.ldst.icache
self.pi = self.ldst.pi
def elaborate(self, platform):
assert hasattr(self, "dcache"), "remember to call set_ldst_interface"
m = super().elaborate(platform)
- comb = m.d.comb
- dcache = self.dcache
+ comb, sync = m.d.comb, m.d.sync
+ dcache, icache = self.dcache, self.icache
+ ldst = self.ldst # managed externally: do not add here
- # link mmu and dcache together
+ # link mmu, dcache and icache together
m.submodules.mmu = mmu = self.mmu
- m.submodules.ldst = ldst = self.ldst
- m.d.comb += dcache.m_in.eq(mmu.d_out)
- m.d.comb += mmu.d_in.eq(dcache.m_out)
+ m.d.comb += dcache.m_in.eq(mmu.d_out) # MMUToDCacheType
+ m.d.comb += mmu.d_in.eq(dcache.m_out) # DCacheToMMUType
+ m.d.comb += icache.m_in.eq(mmu.i_out) # MMUToICacheType
l_in, l_out = mmu.l_in, mmu.l_out
d_in, d_out = dcache.d_in, dcache.d_out
- wb_out, wb_in = dcache.wb_out, dcache.wb_in
# link ldst and MMU together
- comb += l_in.eq(ldst.l_in)
- comb += ldst.l_out.eq(l_out)
+ comb += l_in.eq(ldst.m_out)
+ comb += ldst.m_in.eq(l_out)
- data_i, data_o = self.p.data_i, self.n.data_o
- a_i, b_i, o, spr1_o = data_i.ra, data_i.rb, data_o.o, data_o.spr1
- op = data_i.ctx.op
+ i_data, o_data = self.p.i_data, self.n.o_data
+ op = i_data.ctx.op
+ cia_i = op.cia
msr_i = op.msr
-
- # TODO: link these SPRs somewhere
- dsisr = Signal(64)
- dar = Signal(64)
+ a_i, b_i, spr1_i = i_data.ra, i_data.rb, i_data.spr1
+ o, exc_o, spr1_o = o_data.o, o_data.exception, o_data.spr1
# busy/done signals
- busy = Signal()
- done = Signal()
- m.d.comb += self.n.valid_o.eq(busy & done)
- m.d.comb += self.p.ready_o.eq(~busy)
+ busy = Signal(name="mmu_fsm_busy")
+ done = Signal(name="mmu_fsm_done")
+ m.d.comb += self.n.o_valid.eq(busy & done)
+ m.d.comb += self.p.o_ready.eq(~busy)
# take copy of X-Form SPR field
x_fields = self.fields.FormXFX
spr = Signal(len(x_fields.SPR))
comb += spr.eq(decode_spr_num(x_fields.SPR))
- # based on MSR bits, set priv and virt mode. TODO: 32-bit mode
- comb += d_in.priv_mode.eq(~msr_i[MSR.PR])
- comb += d_in.virt_mode.eq(msr_i[MSR.DR])
- #comb += d_in.mode_32bit.eq(msr_i[MSR.SF]) # ?? err
-
# ok so we have to "pulse" the MMU (or dcache) rather than
# hold the valid hi permanently. guess what this does...
valid = Signal()
m.d.comb += blip.eq(rising_edge(m, valid))
with m.If(~busy):
- with m.If(self.p.valid_i):
- m.d.sync += busy.eq(1)
+ with m.If(self.p.i_valid):
+ sync += busy.eq(1)
with m.Else():
# based on the Micro-Op, we work out which of MMU or DCache
# enabled ("valid") and we twiddle our thumbs until it
# responds ("done").
- # FIXME: properly implement MicrOp.OP_MTSPR and MicrOp.OP_MFSPR
+ # WIP: properly implement MicrOp.OP_MTSPR and MicrOp.OP_MFSPR
with m.Switch(op.insn_type):
+
+ ##########
+ # OP_MTSPR
+ ##########
+
with m.Case(MicrOp.OP_MTSPR):
+ comb += Display("MMUTEST: OP_MTSPR: spr=%i", spr)
# despite redirection this FU **MUST** behave exactly
# like the SPR FU. this **INCLUDES** updating the SPR
# regfile because the CSV file entry for OP_MTSPR
# categorically defines and requires the expectation
# that the CompUnit **WILL** write to the regfile.
- comb += spr1_o.data.eq(spr)
+ comb += spr1_o.data.eq(a_i)
comb += spr1_o.ok.eq(1)
# subset SPR: first check a few bits
+ # XXX NOTE this must now cover **FOUR** values: this
+ # test might not be adequate. DSISR, DAR, PGTBL and PID
+ # must ALL be covered here.
with m.If(~spr[9] & ~spr[5]):
comb += self.debug0.eq(3)
+ #if matched update local cached value
+ #commented out because there is a driver conflict
+ comb += ldst.sprval_in.eq(a_i)
+ comb += ldst.mmu_set_spr.eq(1)
with m.If(spr[0]):
- comb += dsisr.eq(a_i[:32])
+ comb += ldst.mmu_set_dar.eq(1)
with m.Else():
- comb += dar.eq(a_i)
+ comb += ldst.mmu_set_dsisr.eq(1)
comb += done.eq(1)
# pass it over to the MMU instead
with m.Else():
+ # PGTBL and PID
comb += self.debug0.eq(4)
# blip the MMU and wait for it to complete
comb += valid.eq(1) # start "pulse"
comb += l_in.rs.eq(a_i) # incoming operand (RS)
comb += done.eq(1) # FIXME l_out.done
+ ##########
+ # OP_MFSPR
+ ##########
+
with m.Case(MicrOp.OP_MFSPR):
- # subset SPR: first check a few bits
- with m.If(~spr[9] & ~spr[5]):
- comb += self.debug0.eq(5)
+ comb += Display("MMUTEST: OP_MFSPR: spr=%i returns=%i",
+ spr, spr1_i)
+ # partial SPR number decoding perfectly fine
+ with m.If(spr[9] | spr[5]):
+ # identified as an MMU OP_MFSPR, contact the MMU.
+ # interestingly, the read is combinatorial: no need
+ # to set "valid", just set the SPR number
+ comb += l_in.sprn.eq(spr) # which SPR
+ comb += o.data.eq(l_out.sprval)
+ with m.Else():
+ # identified as DSISR or DAR. again: read the SPR
+ # directly, combinatorial access
with m.If(spr[0]):
- comb += o.data.eq(dsisr)
+ comb += o.data.eq(ldst.dar)
with m.Else():
- comb += o.data.eq(dar)
- comb += o.ok.eq(1)
- comb += done.eq(1)
- # pass it over to the MMU instead
- with m.Else():
- comb += self.debug0.eq(6)
- # blip the MMU and wait for it to complete
- comb += valid.eq(1) # start "pulse"
- comb += l_in.valid.eq(blip) # start
- comb += l_in.mtspr.eq(0) # mfspr!=mtspr
- comb += l_in.sprn.eq(spr) # which SPR
- comb += l_in.rs.eq(a_i) # incoming operand (RS)
- comb += o.data.eq(l_out.sprval) # SPR from MMU
- comb += o.ok.eq(l_out.done) # only when l_out valid
- comb += done.eq(1) # FIXME l_out.done
+ comb += o.data.eq(ldst.dsisr)
+
+ comb += o.ok.eq(1)
+ comb += done.eq(1)
- # XXX this one is going to have to go through LDSTCompUnit
- # because it's LDST that has control over dcache
- # (through PortInterface). or, another means is devised
- # so as not to have double-drivers of d_in.valid and addr
- #
- #with m.Case(MicrOp.OP_DCBZ):
- # # activate dcbz mode (spec: v3.0B p850)
- # comb += valid.eq(1) # start "pulse"
- # comb += d_in.valid.eq(blip) # start
- # comb += d_in.dcbz.eq(1) # dcbz mode
- # comb += d_in.addr.eq(a_i + b_i) # addr is (RA|0) + RB
- # comb += done.eq(d_out.store_done) # TODO
- # comb += self.debug0.eq(1)
+ ##########
+ # OP_TLBIE
+ ##########
with m.Case(MicrOp.OP_TLBIE):
+ comb += Display("MMUTEST: OP_TLBIE: insn_bits=%i", spr)
# pass TLBIE request to MMU (spec: v3.0B p1034)
# note that the spr is *not* an actual spr number, it's
# just that those bits happen to match with field bits
# RIC, PRS, R
+ comb += Display("TLBIE: %i %i", spr, l_out.done)
comb += valid.eq(1) # start "pulse"
comb += l_in.valid.eq(blip) # start
comb += l_in.tlbie.eq(1) # mtspr mode
comb += l_in.addr.eq(b_i) # incoming operand (RB)
comb += done.eq(l_out.done) # zzzz
comb += self.debug0.eq(2)
+
+ ##########
+ # OP_FETCH_FAILED
+ ##########
+
+ with m.Case(MicrOp.OP_FETCH_FAILED):
+ comb += Display("MMUTEST: OP_FETCH_FAILED: @%x", cia_i)
+ # trigger an instruction fetch failed MMU event.
+ # PowerDecoder2 drops svstate.pc into NIA for us
+ # really, this should be direct communication with the
+ # MMU, rather than going through LoadStore1. but, doing
+ # so allows for the opportunity to prevent LoadStore1
+ # from accepting any other LD/ST requests.
+ comb += valid.eq(1) # start "pulse"
+ comb += ldst.instr_fault.eq(blip)
+ comb += ldst.priv_mode.eq(~msr_i[MSR.PR])
+ comb += ldst.maddr.eq(cia_i)
+ # XXX should not access this!
+ comb += done.eq(ldst.done)
+ comb += self.debug0.eq(3)
+ # LDST unit contains exception data, which (messily)
+ # is copied over, here. not ideal but it will do for now
+ comb += exc_o.eq(ldst.pi.exc_o)
+
+ ############
+ # OP_ILLEGAL
+ ############
+
with m.Case(MicrOp.OP_ILLEGAL):
comb += self.illegal.eq(1)
- with m.If(self.n.ready_i & self.n.valid_o):
- m.d.sync += busy.eq(0)
+ with m.If(self.n.i_ready & self.n.o_valid):
+ sync += busy.eq(0)
return m
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