riscv/rocket-chip
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Add option to retime D$ way mux into subsequent pipeline stage

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This commit is contained in:
Andrew Waterman 2017-08-01 15:19:25 -07:00
parent 9464c6db40
commit 2eb239d03f
2 changed files with 14 additions and 4 deletions
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17
src/main/scala/rocket/DCache.scala
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@ -184,8 +184,8 @@ class DCacheModule(outer: DCache) extends HellaCacheModule(outer) {
.reduce (_|_))
(s1_meta_hit_way, s1_meta_hit_state, s1_meta, s1_meta_uncorrected(s1_victim_way))
}
val s1_data_way = Mux(inWriteback, releaseWay, s1_hit_way)
val s1_data = Mux1H(s1_data_way, data.io.resp) // retime into s2 if critical
val s1_data_way = Wire(init = Mux(inWriteback, releaseWay, s1_hit_way))
val s1_all_data_ways = Vec(data.io.resp :+ dummyEncodeData(tl_out.d.bits.data))
val s1_mask = Mux(s1_req.cmd === M_PWR, io.cpu.s1_data.mask, new StoreGen(s1_req.typ, s1_req.addr, UInt(0), wordBytes).mask)
val s2_valid = Reg(next=s1_valid_masked && !s1_sfence, init=Bool(false)) && !io.cpu.s2_xcpt.asUInt.orR
@ -210,7 +210,16 @@ class DCacheModule(outer: DCache) extends HellaCacheModule(outer) {
val s2_meta_errors = s2_meta.map(_.error).asUInt
val s2_meta_error = s2_meta_errors.orR
val s2_flush_valid = s2_flush_valid_pre_tag_ecc && !s2_meta_error
val s2_data = RegEnable(s1_data, s1_valid || inWriteback)
val s2_data = {
val en = s1_valid || inWriteback || tl_out.d.fire()
if (cacheParams.pipelineWayMux && nWays > 1) {
val s2_data_way = RegEnable(s1_data_way, en)
val s2_all_data_ways = (0 to nWays).map(i => RegEnable(s1_all_data_ways(i), en && s1_data_way(i)))
Mux1H(s2_data_way, s2_all_data_ways)
} else {
RegEnable(Mux1H(s1_data_way, s1_all_data_ways), en)
}
}
val s2_probe_way = RegEnable(s1_hit_way, s1_probe)
val s2_probe_state = RegEnable(s1_hit_state, s1_probe)
val s2_hit_way = RegEnable(s1_hit_way, s1_valid_not_nacked)
@ -417,7 +426,7 @@ class DCacheModule(outer: DCache) extends HellaCacheModule(outer) {
}
}
when (grantIsUncachedData) {
s2_data := dummyEncodeData(tl_out.d.bits.data)
s1_data_way := 1.U << nWays
s2_req.cmd := M_XRD
s2_req.typ := req.typ
s2_req.tag := req.tag

1
src/main/scala/rocket/HellaCache.scala
View File

@ -27,6 +27,7 @@ case class DCacheParams(
nMMIOs: Int = 1,
blockBytes: Int = 64,
acquireBeforeRelease: Boolean = false,
pipelineWayMux: Boolean = false,
scratch: Option[BigInt] = None) extends L1CacheParams {
def dataScratchpadBytes: Int = scratch.map(_ => nSets*blockBytes).getOrElse(0)