riscv/rocket-chip
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Merge pull request #904 from freechipsproject/fix-dcache-bug

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Fix D$ ready-valid signaling bug
This commit is contained in:
Yunsup Lee 2017-07-29 20:30:47 -07:00 committed by GitHub
commit ea1840c4b1
1 changed files with 5 additions and 4 deletions
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9
src/main/scala/rocket/DCache.scala
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@ -397,7 +397,7 @@ class DCacheModule(outer: DCache) extends HellaCacheModule(outer) {
val blockProbeAfterGrantCount = Reg(init=UInt(0)) val blockProbeAfterGrantCount = Reg(init=UInt(0))
when (blockProbeAfterGrantCount > 0) { blockProbeAfterGrantCount := blockProbeAfterGrantCount - 1 } when (blockProbeAfterGrantCount > 0) { blockProbeAfterGrantCount := blockProbeAfterGrantCount - 1 }
val canAcceptCachedGrant = if (cacheParams.acquireBeforeRelease) release_state === s_ready else true.B val canAcceptCachedGrant = if (cacheParams.acquireBeforeRelease) release_state === s_ready else true.B
tl_out.d.ready := Mux(grantIsCached, tl_out.e.ready && canAcceptCachedGrant, true.B) tl_out.d.ready := Mux(grantIsCached, (!d_first || tl_out.e.ready) && canAcceptCachedGrant, true.B)
when (tl_out.d.fire()) { when (tl_out.d.fire()) {
when (grantIsCached) { when (grantIsCached) {
grantInProgress := true grantInProgress := true
@ -432,9 +432,10 @@ class DCacheModule(outer: DCache) extends HellaCacheModule(outer) {
} }
// data refill // data refill
val doRefillBeat = grantIsRefill && tl_out.d.fire() // note this ready-valid signaling ignores E-channel backpressure, which
dataArb.io.in(1).valid := doRefillBeat // benignly means the data RAM might occasionally be redundantly written
assert(dataArb.io.in(1).ready || !doRefillBeat) dataArb.io.in(1).valid := tl_out.d.valid && grantIsRefill && canAcceptCachedGrant
when (grantIsRefill && !dataArb.io.in(1).ready) { tl_out.d.ready := false }
dataArb.io.in(1).bits.write := true dataArb.io.in(1).bits.write := true
dataArb.io.in(1).bits.addr := s2_req_block_addr | d_address_inc dataArb.io.in(1).bits.addr := s2_req_block_addr | d_address_inc
dataArb.io.in(1).bits.way_en := s2_victim_way dataArb.io.in(1).bits.way_en := s2_victim_way