Merge pull request #449 from ucb-bar/post-refactor-cleanup

Post refactor cleanup

.travis.yml

@@ -36,7 +36,8 @@ env:
     - SUITE=RocketSuiteA
     - SUITE=RocketSuiteB
     - SUITE=RocketSuiteC
-    - SUITE=GroundtestSuite
+    - SUITE=GroundtestSuiteA
+    - SUITE=GroundtestSuiteB
     - SUITE=UnittestSuite
 
 # blacklist private branches

regression/Makefile

@@ -53,10 +53,14 @@ PROJECT=rocketchip
 CONFIGS=DefaultL2Config TinyConfig
 endif
 
-ifeq ($(SUITE),GroundtestSuite)
+ifeq ($(SUITE),GroundtestSuiteA)
 PROJECT=groundtest
-CONFIGS=MemtestConfig MemtestBufferlessConfig MemtestStatelessConfig FancyMemtestConfig \
-	BroadcastRegressionTestConfig BufferlessRegressionTestConfig CacheRegressionTestConfig \
+CONFIGS=MemtestConfig MemtestBufferlessConfig MemtestStatelessConfig FancyMemtestConfig
+endif
+
+ifeq ($(SUITE),GroundtestSuiteB)
+PROJECT=groundtest
+CONFIGS=BroadcastRegressionTestConfig BufferlessRegressionTestConfig CacheRegressionTestConfig \
 	ComparatorConfig ComparatorBufferlessConfig ComparatorL2Config ComparatorStatelessConfig
 endif
 

scripts/tracegen.py

@@ -52,6 +52,8 @@ def main():
       numFinished = numFinished + 1
       if numFinished == total:
         break
+    elif line[0:12] == "using random":
+      continue
     else:
       print line,
 

src/main/scala/coreplex/Configs.scala

@@ -11,6 +11,7 @@ import uncore.coherence._
 import uncore.agents._
 import uncore.devices._
 import uncore.converters._
+import uncore.util._
 import rocket._
 import util._
 import util.ConfigUtils._

src/main/scala/groundtest/CacheFillTest.scala

@@ -3,7 +3,7 @@ package groundtest
 import Chisel._
 import uncore.tilelink._
 import uncore.constants._
-import uncore.agents._
+import uncore.util._
 import util._
 import config._
 

src/main/scala/groundtest/Configs.scala

@@ -6,6 +6,7 @@ import diplomacy._
 import uncore.tilelink._
 import uncore.coherence._
 import uncore.agents._
+import uncore.util._
 import uncore.devices.NTiles
 import junctions._
 import config._

src/main/scala/groundtest/Coreplex.scala

@@ -6,9 +6,10 @@ import diplomacy._
 import coreplex._
 import uncore.devices.NTiles
 import uncore.tilelink2._
-import rocket.TileId
 import uncore.tilelink.TLId
 
+case object TileId extends Field[Int]
+
 class GroundTestCoreplex(implicit p: Parameters) extends BaseCoreplex {
   val tiles = List.tabulate(p(NTiles)) { i =>
     LazyModule(new GroundTestTile()(p.alterPartial({

src/main/scala/groundtest/Regression.scala

@@ -3,7 +3,7 @@ package groundtest
 import Chisel._
 import uncore.tilelink._
 import uncore.constants._
-import uncore.agents._
+import uncore.util._
 import util._
 import rocket._
 import rocketchip._

src/main/scala/groundtest/Tile.scala

@@ -3,7 +3,7 @@ package groundtest
 import Chisel._
 import rocket._
 import uncore.tilelink._
-import uncore.agents.CacheName
+import uncore.util.CacheName
 import uncore.tilelink2._
 import rocketchip.ExtMem
 import diplomacy._

src/main/scala/rocket/Dcache.scala

@@ -5,7 +5,6 @@ package rocket
 import Chisel._
 import Chisel.ImplicitConversions._
 import diplomacy._
-import uncore.agents._
 import uncore.constants._
 import uncore.tilelink2._
 import uncore.util._

src/main/scala/rocket/HellaCache.scala

@@ -6,7 +6,7 @@ import Chisel._
 import config.{Parameters, Field}
 import diplomacy._
 import uncore.tilelink2._
-import uncore.agents._
+import uncore.util._
 import uncore.constants._
 import uncore.tilelink.{TLKey, TLId}
 import util.ParameterizedBundle

src/main/scala/rocket/NBDcache.scala

@@ -5,7 +5,6 @@ package rocket
 import Chisel._
 import Chisel.ImplicitConversions._
 import diplomacy._
-import uncore.agents._
 import uncore.constants._
 import uncore.tilelink._
 import uncore.tilelink2._
@@ -176,15 +175,18 @@ class MSHR(id: Int, edge: TLEdgeOut)(implicit cfg: DCacheConfig, p: Parameters)
   val req_tag = req.addr >> untagBits
   val req_block_addr = (req.addr >> blockOffBits) << blockOffBits
   val idx_match = req_idx === io.req_bits.addr(untagBits-1,blockOffBits)
+
+  val new_coh = Reg(init=ClientMetadata.onReset)
+  val (_, shrink_param, coh_on_clear)    = req.old_meta.coh.onCacheControl(M_FLUSH)
+  val grow_param                                  = new_coh.onAccess(req.cmd)._2
+  val coh_on_grant                                = new_coh.onGrant(req.cmd, io.mem_grant.bits.param)
   // We only accept secondary misses if we haven't yet sent an Acquire to outer memory
   // or if the Acquire that was sent will obtain a Grant with sufficient permissions
   // to let us replay this new request. I.e. we don't handle multiple outstanding
   // Acquires on the same block for now.
-  val cmd_requires_second_acquire = 
-    req.old_meta.coh.requiresAcquireOnSecondaryMiss(req.cmd, io.req_bits.cmd)
-  // Track whether or not a secondary acquire will cause the coherence state
-  // to go from clean to dirty.
-  val dirties_coh = Reg(Bool())
+  val (cmd_requires_second_acquire, is_hit_again, _, dirtier_coh, dirtier_cmd) =
+    new_coh.onSecondaryAccess(req.cmd, io.req_bits.cmd)
+
   val states_before_refill = Seq(s_wb_req, s_wb_resp, s_meta_clear)
   val (_, _, refill_done, refill_address_inc) = edge.addr_inc(io.mem_grant)
   val sec_rdy = idx_match &&
@@ -197,19 +199,6 @@ class MSHR(id: Int, edge: TLEdgeOut)(implicit cfg: DCacheConfig, p: Parameters)
   rpq.io.enq.bits := io.req_bits
   rpq.io.deq.ready := (io.replay.ready && state === s_drain_rpq) || state === s_invalid
 
-  // TODO clean all this coh state business up
-  val new_coh_state = Reg(init=ClientMetadata.onReset)
-  val grow_param = Reg(init=UInt(0))
-  val coh_on_grant = Mux(dirties_coh,
-                          ClientMetadata.maximum,
-                          req.old_meta.coh.onGrant(req.cmd, io.mem_grant.bits.param))
-  val (is_hit, missed_param, coh_on_hit)   = io.req_bits.old_meta.coh.onAccess(io.req_bits.cmd)
-  val (needs_wb, _, _)     = io.req_bits.old_meta.coh.onCacheControl(M_FLUSH)
-  val (_, shrink_param, _)  = req.old_meta.coh.onCacheControl(M_FLUSH)
-  val (hit_again, missed_again_param, _) = req.old_meta.coh.onCacheControl(io.req_bits.cmd)
-  val (_, _, clear_coh_state) = req.old_meta.coh.onCacheControl(M_FLUSH)
-  val (_, after_wb_param, _) = ClientMetadata.onReset.onAccess(req.cmd)
-
   when (state === s_drain_rpq && !rpq.io.deq.valid) {
     state := s_invalid
   }
@@ -221,14 +210,13 @@ class MSHR(id: Int, edge: TLEdgeOut)(implicit cfg: DCacheConfig, p: Parameters)
     state := s_meta_write_resp
   }
   when (state === s_refill_resp && refill_done) {
+    new_coh := coh_on_grant
     state := s_meta_write_req
-    new_coh_state := coh_on_grant
   }
   when (io.mem_acquire.fire()) { // s_refill_req
     state := s_refill_resp
   }
   when (state === s_meta_clear && io.meta_write.ready) {
-    grow_param := after_wb_param
     state := s_refill_req
   }
   when (state === s_wb_resp && io.mem_grant.valid) {
@@ -241,24 +229,26 @@ class MSHR(id: Int, edge: TLEdgeOut)(implicit cfg: DCacheConfig, p: Parameters)
     //If we get a secondary miss that needs more permissions before we've sent
     //  out the primary miss's Acquire, we can upgrade the permissions we're 
     //  going to ask for in s_refill_req
-    when(cmd_requires_second_acquire) {
-      req.cmd := io.req_bits.cmd
-      when(!hit_again) { grow_param := missed_again_param }
+    req.cmd := dirtier_cmd
+    when (is_hit_again) {
+      new_coh := dirtier_coh
     }
-    dirties_coh := dirties_coh || isWrite(io.req_bits.cmd)
   }
   when (io.req_pri_val && io.req_pri_rdy) {
     req := io.req_bits
-    dirties_coh := isWrite(io.req_bits.cmd)
+    val old_coh = io.req_bits.old_meta.coh
+    val needs_wb = old_coh.onCacheControl(M_FLUSH)._1
+    val (is_hit, _, coh_on_hit) = old_coh.onAccess(io.req_bits.cmd)
     when (io.req_bits.tag_match) {
       when (is_hit) { // set dirty bit
+        new_coh := coh_on_hit
         state := s_meta_write_req
-        new_coh_state := coh_on_hit
       }.otherwise { // upgrade permissions
+        new_coh := old_coh
         state := s_refill_req
-        grow_param := missed_param
       }
     }.otherwise { // writback if necessary and refill
+      new_coh := ClientMetadata.onReset
       state := Mux(needs_wb, s_wb_req, s_meta_clear)
     }
   }
@@ -285,7 +275,7 @@ class MSHR(id: Int, edge: TLEdgeOut)(implicit cfg: DCacheConfig, p: Parameters)
 
   io.meta_write.valid := state.isOneOf(s_meta_write_req, s_meta_clear)
   io.meta_write.bits.idx := req_idx
-  io.meta_write.bits.data.coh := Mux(state === s_meta_clear, clear_coh_state, new_coh_state)
+  io.meta_write.bits.data.coh := Mux(state === s_meta_clear, coh_on_clear, new_coh)
   io.meta_write.bits.data.tag := io.tag
   io.meta_write.bits.way_en := req.way_en
 

src/main/scala/rocket/btb.scala

@@ -6,7 +6,7 @@ import Chisel._
 import config._
 import util._
 import Chisel.ImplicitConversions._
-import uncore.agents.PseudoLRU
+import uncore.util.PseudoLRU
 
 case object BtbKey extends Field[BtbParameters]
 

src/main/scala/rocket/ptw.scala

@@ -3,7 +3,7 @@
 package rocket
 
 import Chisel._
-import uncore.agents._
+import uncore.util.PseudoLRU
 import uncore.constants._
 import util._
 import Chisel.ImplicitConversions._

src/main/scala/rocket/rocc.scala

@@ -5,7 +5,7 @@ package rocket
 import Chisel._
 import uncore.tilelink._
 import uncore.constants._
-import uncore.agents.CacheName
+import uncore.util.CacheName
 import util._
 import Chisel.ImplicitConversions._
 import config._

src/main/scala/rocket/rocket.scala

@@ -4,7 +4,7 @@ package rocket
 
 import Chisel._
 import uncore.devices._
-import uncore.agents.CacheName
+import uncore.util.CacheName
 import uncore.constants._
 import uncore.tilelink2._
 import util._

src/main/scala/rocket/tile.scala

@@ -6,7 +6,7 @@ import Chisel._
 import diplomacy._
 import uncore.tilelink._
 import uncore.tilelink2._
-import uncore.agents._
+import uncore.util.{CacheName, CacheBlockBytes}
 import uncore.converters._
 import uncore.devices._
 import util._
@@ -14,7 +14,6 @@ import config._
 import scala.collection.mutable.ListBuffer
 
 case object BuildRoCC extends Field[Seq[RoccParameters]]
-case object TileId extends Field[Int]
 
 case class RoccParameters(
   opcodes: OpcodeSet,
@@ -30,7 +29,6 @@ class RocketTile(tileId: Int)(implicit p: Parameters) extends LazyModule {
   val dcacheParams = coreParams.alterPartial({
     case CacheName => CacheName("L1D")
     case TLId => "L1toL2"
-    case TileId => tileId // TODO using this messes with Heirarchical P&R: change to io.hartid?
   })
   val icacheParams = coreParams.alterPartial({
     case CacheName => CacheName("L1I")

src/main/scala/rocket/tlb.scala

@@ -8,8 +8,7 @@ import Chisel.ImplicitConversions._
 import scala.math._
 import config._
 import diplomacy._
-import uncore.agents._
-import uncore.coherence._
+import uncore.util._
 import uncore.tilelink2._
 
 case object PgLevels extends Field[Int]

src/main/scala/uncore/agents/L2Cache.scala

@@ -5,186 +5,14 @@ package uncore.agents
 import Chisel._
 import scala.reflect.ClassTag
 import junctions.PAddrBits
-import util.ParameterizedBundle
-import uncore.util.AMOALU
 import uncore.coherence._
 import uncore.tilelink._
 import uncore.constants._
 import uncore.util._
 import util._
-import config._
+import config.{Parameters, Field}
 
-case class CacheConfig(
-  nSets:         Int,
-  nWays:         Int,
-  rowBits:       Int,
-  nTLBEntries:   Int,
-  cacheIdBits:   Int,
-  splitMetadata: Boolean)
-case class CacheName(id: String) extends Field[CacheConfig]
-case object CacheName extends Field[CacheName]
-
-case object Replacer extends Field[() => ReplacementPolicy]
-case object L2Replacer extends Field[() => SeqReplacementPolicy]
-case object NPrimaryMisses extends Field[Int]
-case object NSecondaryMisses extends Field[Int]
-case object CacheBlockBytes extends Field[Int]
-case object ECCCode extends Field[Option[Code]]
 case object CacheId extends Field[Int]
-
-trait HasCacheParameters {
-  implicit val p: Parameters
-  val cacheConfig = p(p(CacheName))
-  val nSets = cacheConfig.nSets
-  val blockOffBits = p(CacheBlockOffsetBits)
-  val cacheIdBits = cacheConfig.cacheIdBits
-  val idxBits = log2Up(cacheConfig.nSets)
-  val untagBits = blockOffBits + cacheIdBits + idxBits
-  val tagBits = p(PAddrBits) - untagBits
-  val nWays = cacheConfig.nWays
-  val wayBits = log2Up(nWays)
-  val isDM = nWays == 1
-  val rowBits = cacheConfig.rowBits
-  val rowBytes = rowBits/8
-  val rowOffBits = log2Up(rowBytes)
-  val code = p(ECCCode).getOrElse(new IdentityCode)
-  val hasSplitMetadata = cacheConfig.splitMetadata
-}
-
-abstract class CacheModule(implicit val p: Parameters) extends Module
-  with HasCacheParameters
-abstract class CacheBundle(implicit val p: Parameters) extends ParameterizedBundle()(p)
-  with HasCacheParameters
-
-abstract class ReplacementPolicy {
-  def way: UInt
-  def miss: Unit
-  def hit: Unit
-}
-
-class RandomReplacement(ways: Int) extends ReplacementPolicy {
-  private val replace = Wire(Bool())
-  replace := Bool(false)
-  val lfsr = LFSR16(replace)
-
-  def way = if(ways == 1) UInt(0) else lfsr(log2Up(ways)-1,0)
-  def miss = replace := Bool(true)
-  def hit = {}
-}
-
-abstract class SeqReplacementPolicy {
-  def access(set: UInt): Unit
-  def update(valid: Bool, hit: Bool, set: UInt, way: UInt): Unit
-  def way: UInt
-}
-
-class SeqRandom(n_ways: Int) extends SeqReplacementPolicy {
-  val logic = new RandomReplacement(n_ways)
-  def access(set: UInt) = { }
-  def update(valid: Bool, hit: Bool, set: UInt, way: UInt) = {
-    when (valid && !hit) { logic.miss }
-  }
-  def way = logic.way
-}
-
-class PseudoLRU(n: Int)
-{
-  require(isPow2(n))
-  val state_reg = Reg(Bits(width = n))
-  def access(way: UInt) {
-    state_reg := get_next_state(state_reg,way)
-  }
-  def get_next_state(state: UInt, way: UInt) = {
-    var next_state = state
-    var idx = UInt(1,1)
-    for (i <- log2Up(n)-1 to 0 by -1) {
-      val bit = way(i)
-      next_state = next_state.bitSet(idx, !bit)
-      idx = Cat(idx, bit)
-    }
-    next_state
-  }
-  def replace = get_replace_way(state_reg)
-  def get_replace_way(state: Bits) = {
-    var idx = UInt(1,1)
-    for (i <- 0 until log2Up(n))
-      idx = Cat(idx, state(idx))
-    idx(log2Up(n)-1,0)
-  }
-}
-
-class SeqPLRU(n_sets: Int, n_ways: Int) extends SeqReplacementPolicy {
-  val state = SeqMem(n_sets, Bits(width = n_ways-1))
-  val logic = new PseudoLRU(n_ways)
-  val current_state = Wire(Bits())
-  val plru_way = logic.get_replace_way(current_state)
-  val next_state = Wire(Bits())
-
-  def access(set: UInt) = {
-    current_state := Cat(state.read(set), Bits(0, width = 1))
-  }
-
-  def update(valid: Bool, hit: Bool, set: UInt, way: UInt) = {
-    val update_way = Mux(hit, way, plru_way)
-    next_state := logic.get_next_state(current_state, update_way)
-    when (valid) { state.write(set, next_state(n_ways-1,1)) }
-  }
-
-  def way = plru_way
-}
-
-abstract class Metadata(implicit p: Parameters) extends CacheBundle()(p) {
-  val tag = Bits(width = tagBits)
-}
-
-class MetaReadReq(implicit p: Parameters) extends CacheBundle()(p) {
-  val idx  = Bits(width = idxBits)
-  val way_en = Bits(width = nWays)
-}
-
-class MetaWriteReq[T <: Metadata](gen: T)(implicit p: Parameters) extends MetaReadReq()(p) {
-  val data = gen.cloneType
-  override def cloneType = new MetaWriteReq(gen)(p).asInstanceOf[this.type]
-}
-
-class MetadataArray[T <: Metadata](onReset: () => T)(implicit p: Parameters) extends CacheModule()(p) {
-  val rstVal = onReset()
-  val io = new Bundle {
-    val read = Decoupled(new MetaReadReq).flip
-    val write = Decoupled(new MetaWriteReq(rstVal)).flip
-    val resp = Vec(nWays, rstVal.cloneType).asOutput
-  }
-  val rst_cnt = Reg(init=UInt(0, log2Up(nSets+1)))
-  val rst = rst_cnt < UInt(nSets)
-  val waddr = Mux(rst, rst_cnt, io.write.bits.idx)
-  val wdata = Mux(rst, rstVal, io.write.bits.data).asUInt
-  val wmask = Mux(rst || Bool(nWays == 1), SInt(-1), io.write.bits.way_en.asSInt).toBools
-  val rmask = Mux(rst || Bool(nWays == 1), SInt(-1), io.read.bits.way_en.asSInt).toBools
-  when (rst) { rst_cnt := rst_cnt+UInt(1) }
-
-  val metabits = rstVal.getWidth
-
-  if (hasSplitMetadata) {
-    val tag_arrs = List.fill(nWays){ SeqMem(nSets, UInt(width = metabits)) }
-    val tag_readout = Wire(Vec(nWays,rstVal.cloneType))
-    (0 until nWays).foreach { (i) =>
-      when (rst || (io.write.valid && wmask(i))) {
-        tag_arrs(i).write(waddr, wdata)
-      }
-      io.resp(i) := rstVal.fromBits(tag_arrs(i).read(io.read.bits.idx, io.read.valid && rmask(i)))
-    }
-  } else {
-    val tag_arr = SeqMem(nSets, Vec(nWays, UInt(width = metabits)))
-    when (rst || io.write.valid) {
-      tag_arr.write(waddr, Vec.fill(nWays)(wdata), wmask)
-    }
-    io.resp := tag_arr.read(io.read.bits.idx, io.read.valid).map(rstVal.fromBits(_))
-  }
-
-  io.read.ready := !rst && !io.write.valid // so really this could be a 6T RAM
-  io.write.ready := !rst
-}
-
 case object L2DirectoryRepresentation extends Field[DirectoryRepresentation]
 
 trait HasOuterCacheParameters extends HasCacheParameters with HasCoherenceAgentParameters {

src/main/scala/uncore/tilelink2/Metadata.scala

@@ -88,12 +88,6 @@ class ClientMetadata extends Bundle {
       Cat(wr, toT)   -> Dirty))
   }
 
-  /** Does a secondary miss on the block require another Acquire message */
-  def requiresAcquireOnSecondaryMiss(first_cmd: UInt, second_cmd: UInt): Bool = {
-    import MemoryOpCategories._
-    isWriteIntent(second_cmd) && !isWriteIntent(first_cmd)
-  }
-
   /** Does this cache have permissions on this block sufficient to perform op,
     * and what to do next (Acquire message param or updated metadata). */
   def onAccess(cmd: UInt): (Bool, UInt, ClientMetadata) = {
@@ -101,6 +95,20 @@ class ClientMetadata extends Bundle {
     (r._1, r._2, ClientMetadata(r._2))
   }
 
+  /** Does a secondary miss on the block require another Acquire message */
+  def onSecondaryAccess(first_cmd: UInt, second_cmd: UInt): (Bool, Bool, UInt, ClientMetadata, UInt) = {
+    import MemoryOpCategories._
+    val r1 = growStarter(first_cmd)
+    val r2 = growStarter(second_cmd)
+    val needs_second_acq = isWriteIntent(second_cmd) && !isWriteIntent(first_cmd)
+    val hit_again = r1._1 && r2._1
+    val dirties = categorize(second_cmd) === wr
+    val biggest_grow_param = Mux(dirties, r2._2, r1._2)
+    val dirtiest_state = ClientMetadata(biggest_grow_param)
+    val dirtiest_cmd = Mux(dirties, second_cmd, first_cmd)
+    (needs_second_acq, hit_again, biggest_grow_param, dirtiest_state, dirtiest_cmd)
+  }
+
   /** Metadata change on a returned Grant */
   def onGrant(cmd: UInt, param: UInt): ClientMetadata = ClientMetadata(growFinisher(cmd, param))
 

src/main/scala/uncore/util/Cache.scala

@@ -0,0 +1,180 @@
+// See LICENSE for license details.
+
+package uncore.util
+
+import Chisel._
+import config.{Parameters, Field}
+import junctions.PAddrBits
+import util.ParameterizedBundle
+import uncore.constants._
+
+case class CacheConfig(
+  nSets:         Int,
+  nWays:         Int,
+  rowBits:       Int,
+  nTLBEntries:   Int,
+  cacheIdBits:   Int,
+  splitMetadata: Boolean)
+case class CacheName(id: String) extends Field[CacheConfig]
+case object CacheName extends Field[CacheName]
+
+case object Replacer extends Field[() => ReplacementPolicy]
+case object L2Replacer extends Field[() => SeqReplacementPolicy]
+case object NPrimaryMisses extends Field[Int]
+case object NSecondaryMisses extends Field[Int]
+case object CacheBlockBytes extends Field[Int]
+case object ECCCode extends Field[Option[Code]]
+
+trait HasCacheParameters {
+  implicit val p: Parameters
+  val cacheConfig = p(p(CacheName))
+  val nSets = cacheConfig.nSets
+  val blockOffBits = log2Up(p(CacheBlockBytes))
+  val cacheIdBits = cacheConfig.cacheIdBits
+  val idxBits = log2Up(cacheConfig.nSets)
+  val untagBits = blockOffBits + cacheIdBits + idxBits
+  val tagBits = p(PAddrBits) - untagBits
+  val nWays = cacheConfig.nWays
+  val wayBits = log2Up(nWays)
+  val isDM = nWays == 1
+  val rowBits = cacheConfig.rowBits
+  val rowBytes = rowBits/8
+  val rowOffBits = log2Up(rowBytes)
+  val code = p(ECCCode).getOrElse(new IdentityCode)
+  val hasSplitMetadata = cacheConfig.splitMetadata
+}
+
+abstract class CacheModule(implicit val p: Parameters) extends Module
+  with HasCacheParameters
+abstract class CacheBundle(implicit val p: Parameters) extends ParameterizedBundle()(p)
+  with HasCacheParameters
+
+abstract class ReplacementPolicy {
+  def way: UInt
+  def miss: Unit
+  def hit: Unit
+}
+
+class RandomReplacement(ways: Int) extends ReplacementPolicy {
+  private val replace = Wire(Bool())
+  replace := Bool(false)
+  val lfsr = LFSR16(replace)
+
+  def way = if(ways == 1) UInt(0) else lfsr(log2Up(ways)-1,0)
+  def miss = replace := Bool(true)
+  def hit = {}
+}
+
+abstract class SeqReplacementPolicy {
+  def access(set: UInt): Unit
+  def update(valid: Bool, hit: Bool, set: UInt, way: UInt): Unit
+  def way: UInt
+}
+
+class SeqRandom(n_ways: Int) extends SeqReplacementPolicy {
+  val logic = new RandomReplacement(n_ways)
+  def access(set: UInt) = { }
+  def update(valid: Bool, hit: Bool, set: UInt, way: UInt) = {
+    when (valid && !hit) { logic.miss }
+  }
+  def way = logic.way
+}
+
+class PseudoLRU(n: Int)
+{
+  require(isPow2(n))
+  val state_reg = Reg(Bits(width = n))
+  def access(way: UInt) {
+    state_reg := get_next_state(state_reg,way)
+  }
+  def get_next_state(state: UInt, way: UInt) = {
+    var next_state = state
+    var idx = UInt(1,1)
+    for (i <- log2Up(n)-1 to 0 by -1) {
+      val bit = way(i)
+      next_state = next_state.bitSet(idx, !bit)
+      idx = Cat(idx, bit)
+    }
+    next_state
+  }
+  def replace = get_replace_way(state_reg)
+  def get_replace_way(state: Bits) = {
+    var idx = UInt(1,1)
+    for (i <- 0 until log2Up(n))
+      idx = Cat(idx, state(idx))
+    idx(log2Up(n)-1,0)
+  }
+}
+
+class SeqPLRU(n_sets: Int, n_ways: Int) extends SeqReplacementPolicy {
+  val state = SeqMem(n_sets, Bits(width = n_ways-1))
+  val logic = new PseudoLRU(n_ways)
+  val current_state = Wire(Bits())
+  val plru_way = logic.get_replace_way(current_state)
+  val next_state = Wire(Bits())
+
+  def access(set: UInt) = {
+    current_state := Cat(state.read(set), Bits(0, width = 1))
+  }
+
+  def update(valid: Bool, hit: Bool, set: UInt, way: UInt) = {
+    val update_way = Mux(hit, way, plru_way)
+    next_state := logic.get_next_state(current_state, update_way)
+    when (valid) { state.write(set, next_state(n_ways-1,1)) }
+  }
+
+  def way = plru_way
+}
+
+abstract class Metadata(implicit p: Parameters) extends CacheBundle()(p) {
+  val tag = Bits(width = tagBits)
+}
+
+class MetaReadReq(implicit p: Parameters) extends CacheBundle()(p) {
+  val idx  = Bits(width = idxBits)
+  val way_en = Bits(width = nWays)
+}
+
+class MetaWriteReq[T <: Metadata](gen: T)(implicit p: Parameters) extends MetaReadReq()(p) {
+  val data = gen.cloneType
+  override def cloneType = new MetaWriteReq(gen)(p).asInstanceOf[this.type]
+}
+
+class MetadataArray[T <: Metadata](onReset: () => T)(implicit p: Parameters) extends CacheModule()(p) {
+  val rstVal = onReset()
+  val io = new Bundle {
+    val read = Decoupled(new MetaReadReq).flip
+    val write = Decoupled(new MetaWriteReq(rstVal)).flip
+    val resp = Vec(nWays, rstVal.cloneType).asOutput
+  }
+  val rst_cnt = Reg(init=UInt(0, log2Up(nSets+1)))
+  val rst = rst_cnt < UInt(nSets)
+  val waddr = Mux(rst, rst_cnt, io.write.bits.idx)
+  val wdata = Mux(rst, rstVal, io.write.bits.data).asUInt
+  val wmask = Mux(rst || Bool(nWays == 1), SInt(-1), io.write.bits.way_en.asSInt).toBools
+  val rmask = Mux(rst || Bool(nWays == 1), SInt(-1), io.read.bits.way_en.asSInt).toBools
+  when (rst) { rst_cnt := rst_cnt+UInt(1) }
+
+  val metabits = rstVal.getWidth
+
+  if (hasSplitMetadata) {
+    val tag_arrs = List.fill(nWays){ SeqMem(nSets, UInt(width = metabits)) }
+    val tag_readout = Wire(Vec(nWays,rstVal.cloneType))
+    (0 until nWays).foreach { (i) =>
+      when (rst || (io.write.valid && wmask(i))) {
+        tag_arrs(i).write(waddr, wdata)
+      }
+      io.resp(i) := rstVal.fromBits(tag_arrs(i).read(io.read.bits.idx, io.read.valid && rmask(i)))
+    }
+  } else {
+    val tag_arr = SeqMem(nSets, Vec(nWays, UInt(width = metabits)))
+    when (rst || io.write.valid) {
+      tag_arr.write(waddr, Vec.fill(nWays)(wdata), wmask)
+    }
+    io.resp := tag_arr.read(io.read.bits.idx, io.read.valid).map(rstVal.fromBits(_))
+  }
+
+  io.read.ready := !rst && !io.write.valid // so really this could be a 6T RAM
+  io.write.ready := !rst
+}
+

src/main/scala/uncore/util/Ecc.scala

@@ -1,6 +1,6 @@
 // See LICENSE for license details.
 
-package uncore.agents
+package uncore.util
 
 import Chisel._
 import util._