riscv/rocket-chip
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change D$ to use FourStateCoherence protocol

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instead of ThreeStateIncoherence.
This commit is contained in:
Andrew Waterman 2012-03-07 01:26:35 -08:00
parent 6e2610b0ad
commit a0c9452b86
2 changed files with 45 additions and 40 deletions
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31
rocket/src/main/scala/coherence.scala
View File

@ -121,17 +121,18 @@ trait ThreeStateIncoherence extends CoherencePolicy {
Mux(write, tileDirty, Mux(read, Mux(state === tileDirty, tileDirty, tileClean), state))
}
def newStateOnHit(cmd: Bits, state: UFix): UFix = newState(cmd, state)
def newStateOnPrimaryMiss(cmd: Bits): UFix = newState(cmd, tileInvalid)
def newStateOnSecondaryMiss(cmd: Bits, state: UFix): UFix = {
def newTransactionOnPrimaryMiss(cmd: Bits, state: UFix): UFix = {
val (read, write) = cpuCmdToRW(cmd)
Mux(write, tileDirty, state)
Mux(write, X_INIT_READ_EXCLUSIVE, X_INIT_READ_SHARED)
}
def newTransactionOnMiss(cmd: Bits, state: UFix): UFix = X_INIT_READ_EXCLUSIVE
def newStateOnTransactionRep(cmd: Bits, incoming: TransactionReply, outstanding: TransactionInit): UFix = {
def newTransactionOnSecondaryMiss(cmd: Bits, state: UFix, outstanding: TransactionInit): UFix = {
val (read, write) = cpuCmdToRW(cmd)
Mux(write, tileDirty, tileClean)
Mux(write, X_INIT_READ_EXCLUSIVE, outstanding.t_type)
}
def needsSecondaryXact(cmd: Bits, outstanding: TransactionInit): Bool = Bool(false)
def newStateOnTransactionRep(incoming: TransactionReply, outstanding: TransactionInit): UFix = {
Mux(outstanding.t_type === X_INIT_READ_EXCLUSIVE, tileDirty, tileClean)
}
def newStateOnProbeReq(incoming: ProbeRequest, state: UFix): Bits = state
def probeReplyHasData (reply: ProbeReply): Bool = Bool(false)
def transactionInitHasData (init: TransactionInit): Bool = (init.t_type != X_INIT_WRITE_UNCACHED)
@ -166,11 +167,20 @@ trait FourStateCoherence extends CoherencePolicy {
val (read, write) = cpuCmdToRW(cmd)
Mux(write, tileExclusiveDirty, state)
}
def newTransactionOnMiss(cmd: Bits, state: UFix): UFix = {
def newTransactionOnPrimaryMiss(cmd: Bits, state: UFix): UFix = {
val (read, write) = cpuCmdToRW(cmd)
Mux(write, X_INIT_READ_EXCLUSIVE, X_INIT_READ_SHARED)
}
def newStateOnTransactionRep(cmd: Bits, incoming: TransactionReply, outstanding: TransactionInit): UFix = {
def newTransactionOnSecondaryMiss(cmd: Bits, state: UFix, outstanding: TransactionInit): UFix = {
val (read, write) = cpuCmdToRW(cmd)
Mux(write, X_INIT_READ_EXCLUSIVE, outstanding.t_type)
}
def needsSecondaryXact(cmd: Bits, outstanding: TransactionInit): Bool = {
val (read, write) = cpuCmdToRW(cmd)
(read && (outstanding.t_type === X_INIT_READ_UNCACHED || outstanding.t_type === X_INIT_WRITE_UNCACHED)) ||
(write && (outstanding.t_type != X_INIT_READ_EXCLUSIVE))
}
def newStateOnTransactionRep(incoming: TransactionReply, outstanding: TransactionInit): UFix = {
MuxLookup(incoming.t_type, tileInvalid, Array(
X_REP_READ_SHARED -> tileShared,
X_REP_READ_EXCLUSIVE -> Mux(outstanding.t_type === X_INIT_READ_EXCLUSIVE, tileExclusiveDirty, tileExclusiveClean),
@ -179,11 +189,6 @@ trait FourStateCoherence extends CoherencePolicy {
X_REP_WRITE_UNCACHED -> tileInvalid
))
}
def needsSecondaryXact(cmd: Bits, outstanding: TransactionInit): Bool = {
val (read, write) = cpuCmdToRW(cmd)
(read && (outstanding.t_type === X_INIT_READ_UNCACHED || outstanding.t_type === X_INIT_WRITE_UNCACHED)) ||
(write && (outstanding.t_type != X_INIT_READ_EXCLUSIVE))
}
def newStateOnProbeReq(incoming: ProbeRequest, state: UFix): Bits = {
MuxLookup(incoming.p_type, state, Array(

38
rocket/src/main/scala/nbdcache.scala
View File

@ -163,7 +163,7 @@ class MetaArrayArrayReq extends Bundle {
val way_en = Bits(width = NWAYS)
}
class MSHR(id: Int) extends Component with ThreeStateIncoherence {
class MSHR(id: Int) extends Component with FourStateCoherence {
val io = new Bundle {
val req_pri_val = Bool(INPUT)
val req_pri_rdy = Bool(OUTPUT)
@ -187,6 +187,7 @@ class MSHR(id: Int) extends Component with ThreeStateIncoherence {
}
val valid = Reg(resetVal = Bool(false))
val xact_type = Reg { UFix() }
val state = Reg { UFix() }
val requested = Reg { Bool() }
val refilled = Reg { Bool() }
@ -196,10 +197,8 @@ class MSHR(id: Int) extends Component with ThreeStateIncoherence {
val way_oh_ = Reg { Bits() }
val req_cmd = io.req_bits.cmd
val req_load = (req_cmd === M_XRD) || (req_cmd === M_PFR)
val req_use_rpq = (req_cmd != M_PFR) && (req_cmd != M_PFW)
val next_state = Mux(io.req_sec_val && io.req_sec_rdy, newStateOnSecondaryMiss(req_cmd, state), state)
val sec_rdy = io.idx_match && !refilled && (needsWriteback(state) || !requested || req_load)
val sec_rdy = io.idx_match && !refilled && !((requested || io.mem_req.ready) && needsSecondaryXact(req_cmd, io.mem_req.bits))
val rpq = (new queue(NRPQ)) { new RPQEntry }
rpq.io.enq.valid := (io.req_pri_val && io.req_pri_rdy || io.req_sec_val && sec_rdy) && req_use_rpq
@ -213,17 +212,6 @@ class MSHR(id: Int) extends Component with ThreeStateIncoherence {
finish_q.io.enq.valid := refill_done
finish_q.io.enq.bits := io.mem_rep.bits.global_xact_id
when (io.req_pri_val && io.req_pri_rdy) {
valid := Bool(true)
state := newStateOnPrimaryMiss(req_cmd)
requested := Bool(false)
refilled := Bool(false)
refill_count := UFix(0)
ppn := io.req_bits.ppn
idx_ := io.req_bits.idx
way_oh_ := io.req_bits.way_oh
}
.otherwise {
when (io.mem_req.valid && io.mem_req.ready) {
requested := Bool(true)
}
@ -232,6 +220,7 @@ class MSHR(id: Int) extends Component with ThreeStateIncoherence {
}
when (io.mem_rep.valid && io.mem_rep.bits.tile_xact_id === UFix(id)) {
refill_count := refill_count + UFix(1)
state := newStateOnTransactionRep(io.mem_rep.bits, io.mem_req.bits)
}
when (refill_done) {
refilled := Bool(true)
@ -239,7 +228,18 @@ class MSHR(id: Int) extends Component with ThreeStateIncoherence {
when (io.meta_req.valid && io.meta_req.ready) {
valid := Bool(false)
}
state := next_state
when (io.req_sec_val && io.req_sec_rdy) {
xact_type := newTransactionOnSecondaryMiss(req_cmd, newStateOnFlush(), io.mem_req.bits)
}
when (io.req_pri_val && io.req_pri_rdy) {
valid := Bool(true)
xact_type := newTransactionOnPrimaryMiss(req_cmd, newStateOnFlush())
requested := Bool(false)
refilled := Bool(false)
refill_count := UFix(0)
ppn := io.req_bits.ppn
idx_ := io.req_bits.idx
way_oh_ := io.req_bits.way_oh
}
io.idx_match := valid && (idx_ === io.req_bits.idx)
@ -258,7 +258,7 @@ class MSHR(id: Int) extends Component with ThreeStateIncoherence {
io.meta_req.bits.way_en := way_oh_
io.mem_req.valid := valid && !requested
io.mem_req.bits.t_type := Mux(needsWriteback(next_state), X_INIT_READ_EXCLUSIVE, X_INIT_READ_SHARED)
io.mem_req.bits.t_type := xact_type
io.mem_req.bits.address := Cat(ppn, idx_).toUFix
io.mem_req.bits.tile_xact_id := Bits(id)
io.mem_finish <> finish_q.io.deq
@ -449,7 +449,7 @@ class WritebackUnit extends Component {
io.mem_finish <> finish_q.io.deq
}
class FlushUnit(lines: Int) extends Component with ThreeStateIncoherence{
class FlushUnit(lines: Int) extends Component with FourStateCoherence{
val io = new Bundle {
val req = (new ioDecoupled) { Bits(width = DCACHE_TAG_BITS) }.flip
val resp = (new ioDecoupled) { Bits(width = DCACHE_TAG_BITS) }
@ -667,7 +667,7 @@ abstract class HellaCache extends Component {
def newStateOnHit(cmd: Bits, state: UFix): UFix
}
class HellaCacheUniproc extends HellaCache with ThreeStateIncoherence {
class HellaCacheUniproc extends HellaCache with FourStateCoherence {
val io = new Bundle {
val cpu = new ioDmem()
val mem = new ioTileLink