rocket-chip/uncore/src/uncore.scala

package uncore

import Chisel._
import Constants._

class TrackerProbeData(implicit conf: CoherenceHubConfiguration) extends Bundle {
  val client_id = Bits(width = conf.ln.idBits)
}

class TrackerAllocReq(implicit conf: CoherenceHubConfiguration) extends Bundle {
  val acquire = new Acquire()
  val client_id = Bits(width = conf.ln.idBits)
  override def clone = { new TrackerAllocReq().asInstanceOf[this.type] }
}

class TrackerDependency extends Bundle {
  val master_xact_id = Bits(width = MASTER_XACT_ID_BITS)
}

class XactTrackerBroadcast(id: Int)(implicit conf: CoherenceHubConfiguration) extends Component {
  val co = conf.co
  val io = new Bundle {
    val alloc_req       = (new FIFOIO) { new TrackerAllocReq }.flip
    val p_data          = (new PipeIO) { new TrackerProbeData }.flip
    val can_alloc       = Bool(INPUT)
    val grant_ack     = Bool(INPUT)
    val release_cnt_dec   = Bits(INPUT, conf.ln.nTiles)
    val probe_cnt_inc   = Bits(INPUT, conf.ln.nTiles)
    val tile_incoherent = Bits(INPUT, conf.ln.nTiles)
    val release_data      = (new PipeIO) { new ReleaseData }.flip
    val acquire_data     = (new PipeIO) { new AcquireData }.flip
    val sent_grant_ack  = Bool(INPUT)
    val release_data_dep  = (new PipeIO) { new TrackerDependency }.flip
    val acquire_data_dep = (new PipeIO) { new TrackerDependency }.flip

    val mem_req_cmd     = (new FIFOIO) { new MemReqCmd }
    val mem_req_data    = (new FIFOIO) { new MemData }
    val mem_req_lock    = Bool(OUTPUT)
    val probe       = (new FIFOIO) { new Probe }
    val busy            = Bool(OUTPUT)
    val addr            = Bits(OUTPUT, PADDR_BITS - OFFSET_BITS)
    val init_client_id    = Bits(OUTPUT, conf.ln.idBits)
    val release_client_id   = Bits(OUTPUT, conf.ln.idBits)
    val client_xact_id    = Bits(OUTPUT, CLIENT_XACT_ID_BITS)
    val sharer_count    = Bits(OUTPUT, conf.ln.idBits+1)
    val a_type          = Bits(OUTPUT, ACQUIRE_TYPE_MAX_BITS)
    val push_probe      = Bits(OUTPUT, conf.ln.nTiles)
    val pop_release       = Bits(OUTPUT, conf.ln.nTiles)
    val pop_release_data  = Bits(OUTPUT, conf.ln.nTiles)
    val pop_release_dep   = Bits(OUTPUT, conf.ln.nTiles)
    val pop_acquire      = Bits(OUTPUT, conf.ln.nTiles)
    val pop_acquire_data = Bits(OUTPUT, conf.ln.nTiles)
    val pop_acquire_dep  = Bits(OUTPUT, conf.ln.nTiles)
    val send_grant_ack  = Bool(OUTPUT)
  }

  def doMemReqWrite(req_cmd: FIFOIO[MemReqCmd], req_data: FIFOIO[MemData], lock: Bool,  data: PipeIO[MemData], trigger: Bool, cmd_sent: Bool, pop_data: Bits, pop_dep: Bits, at_front_of_dep_queue: Bool, client_id: UFix) {
    req_cmd.bits.rw := Bool(true)
    req_data.bits := data.bits
    when(req_cmd.ready && req_cmd.valid) {
      cmd_sent := Bool(true)
    }
    when (at_front_of_dep_queue) {
      req_cmd.valid := !cmd_sent && req_data.ready && data.valid
      lock := data.valid || cmd_sent
      when (req_cmd.ready || cmd_sent) {
        req_data.valid := data.valid
        when(req_data.ready) {
          pop_data := UFix(1) << client_id
          when (data.valid) {
            mem_cnt  := mem_cnt_next
            when(mem_cnt === UFix(REFILL_CYCLES-1)) {
              pop_dep := UFix(1) << client_id
              trigger := Bool(false)
            }
          }
        }
      }
    }
  }

  def doMemReqRead(req_cmd: FIFOIO[MemReqCmd], trigger: Bool) {
    req_cmd.valid := Bool(true)
    req_cmd.bits.rw := Bool(false)
    when(req_cmd.ready) {
      trigger := Bool(false)
    }
  }

  val s_idle :: s_ack :: s_mem :: s_probe :: s_busy :: Nil = Enum(5){ UFix() }
  val state = Reg(resetVal = s_idle)
  val xact  = Reg{ new Acquire }
  val init_client_id_ = Reg{ Bits() }
  val release_count = if (conf.ln.nTiles == 1) UFix(0) else Reg(resetVal = UFix(0, width = log2Up(conf.ln.nTiles)))
  val probe_flags = Reg(resetVal = Bits(0, width = conf.ln.nTiles))
  val release_client_id_ = Reg{ Bits() }
  val x_needs_read = Reg(resetVal = Bool(false))
  val acquire_data_needs_write = Reg(resetVal = Bool(false))
  val release_data_needs_write = Reg(resetVal = Bool(false))
  val x_w_mem_cmd_sent = Reg(resetVal = Bool(false))
  val p_w_mem_cmd_sent = Reg(resetVal = Bool(false))
  val mem_cnt = Reg(resetVal = UFix(0, width = log2Up(REFILL_CYCLES)))
  val mem_cnt_next = mem_cnt + UFix(1)
  val mem_cnt_max = ~UFix(0, width = log2Up(REFILL_CYCLES))
  val probe_initial_flags = Bits(width = conf.ln.nTiles)
  probe_initial_flags := Bits(0)
  if (conf.ln.nTiles > 1) {
    // issue self-probes for uncached read xacts to facilitate I$ coherence
    // TODO: this is hackish; figure out how to do it more systematically
    val probe_self = co match {
      case u: CoherencePolicyWithUncached => u.isUncachedReadTransaction(io.alloc_req.bits.acquire)
      case _ => Bool(false)
    }
    val myflag = Mux(probe_self, Bits(0), UFixToOH(io.alloc_req.bits.client_id(log2Up(conf.ln.nTiles)-1,0)))
    probe_initial_flags := ~(io.tile_incoherent | myflag)
  }

  io.busy := state != s_idle
  io.addr := xact.addr
  io.init_client_id := init_client_id_
  io.release_client_id := release_client_id_
  io.client_xact_id := xact.client_xact_id
  io.sharer_count := UFix(conf.ln.nTiles) // TODO: Broadcast only
  io.a_type := xact.a_type

  io.mem_req_cmd.valid := Bool(false)
  io.mem_req_cmd.bits.rw := Bool(false)
  io.mem_req_cmd.bits.addr := xact.addr
  io.mem_req_cmd.bits.tag := UFix(id)
  io.mem_req_data.valid := Bool(false)
  io.mem_req_data.bits.data := UFix(0)
  io.mem_req_lock := Bool(false)
  io.probe.valid := Bool(false)
  io.probe.bits.p_type := co.getProbeType(xact.a_type, UFix(0))
  io.probe.bits.master_xact_id  := UFix(id)
  io.probe.bits.addr := xact.addr
  io.push_probe      := Bits(0, width = conf.ln.nTiles)
  io.pop_release       := Bits(0, width = conf.ln.nTiles)
  io.pop_release_data  := Bits(0, width = conf.ln.nTiles)
  io.pop_release_dep   := Bits(0, width = conf.ln.nTiles)
  io.pop_acquire      := Bits(0, width = conf.ln.nTiles)
  io.pop_acquire_data := Bits(0, width = conf.ln.nTiles)
  io.pop_acquire_dep  := Bits(0, width = conf.ln.nTiles)
  io.send_grant_ack  := Bool(false)

  switch (state) {
    is(s_idle) {
      when( io.alloc_req.valid && io.can_alloc ) {
        xact := io.alloc_req.bits.acquire
        init_client_id_ := io.alloc_req.bits.client_id
        acquire_data_needs_write := co.messageHasData(io.alloc_req.bits.acquire)
        x_needs_read := co.needsMemRead(io.alloc_req.bits.acquire.a_type, UFix(0))
        probe_flags := probe_initial_flags
        mem_cnt := UFix(0)
        p_w_mem_cmd_sent := Bool(false)
        x_w_mem_cmd_sent := Bool(false)
        io.pop_acquire := UFix(1) << io.alloc_req.bits.client_id
        if(conf.ln.nTiles > 1) {
          release_count := PopCount(probe_initial_flags)
          state := Mux(probe_initial_flags.orR, s_probe, s_mem)
        } else state := s_mem
      }
    }
    is(s_probe) {
      when(probe_flags.orR) {
        io.push_probe := probe_flags
        io.probe.valid := Bool(true)
      }
      when(io.probe_cnt_inc.orR) {
        probe_flags := probe_flags & ~io.probe_cnt_inc // unflag sent reqs
      }
      when(io.release_cnt_dec.orR) {
        val dec = PopCount(io.release_cnt_dec)
        io.pop_release := io.release_cnt_dec
        if(conf.ln.nTiles > 1) release_count := release_count - dec
        when(release_count === dec) {
          state := s_mem
        }
      }
      when(io.p_data.valid) {
        release_data_needs_write := Bool(true)
        release_client_id_ := io.p_data.bits.client_id
      }
    }
    is(s_mem) {
      when (release_data_needs_write) {
        doMemReqWrite(io.mem_req_cmd, 
                      io.mem_req_data, 
                      io.mem_req_lock, 
                      io.release_data, 
                      release_data_needs_write, 
                      p_w_mem_cmd_sent, 
                      io.pop_release_data, 
                      io.pop_release_dep, 
                      io.release_data_dep.valid && (io.release_data_dep.bits.master_xact_id === UFix(id)),
                      release_client_id_)
      } . elsewhen(acquire_data_needs_write) {
        doMemReqWrite(io.mem_req_cmd, 
                      io.mem_req_data, 
                      io.mem_req_lock, 
                      io.acquire_data, 
                      acquire_data_needs_write, 
                      x_w_mem_cmd_sent, 
                      io.pop_acquire_data, 
                      io.pop_acquire_dep,
                      io.acquire_data_dep.valid && (io.acquire_data_dep.bits.master_xact_id === UFix(id)),
                      init_client_id_)
      } . elsewhen (x_needs_read) {    
        doMemReqRead(io.mem_req_cmd, x_needs_read)
      } . otherwise { 
        state := Mux(co.needsAckReply(xact.a_type, UFix(0)), s_ack, s_busy)
      }
    }
    is(s_ack) {
      io.send_grant_ack := Bool(true)
      when(io.sent_grant_ack) { state := s_busy }
    }
    is(s_busy) { // Nothing left to do but wait for transaction to complete
      when (io.grant_ack) {
        state := s_idle
      }
    }
  }
}

case class CoherenceHubConfiguration(co: CoherencePolicy, ln: LogicalNetworkConfiguration)

class CoherenceHubAdapter(implicit conf: LogicalNetworkConfiguration) extends Component with MasterCoherenceAgent {
  val io = new Bundle {
    val net = (new TileLinkIO).flip
    val hub = Vec(conf.nTiles) { new TileLinkIO }
  }

  val netClientProducedSubBundles = io.net.getClass.getMethods.filter( x =>
    classOf[ClientSourcedIO[Data]].isAssignableFrom(x.getReturnType)).map{ m =>
      m.invoke(io.net).asInstanceOf[ClientSourcedIO[LogicalNetworkIO[Data]]] } 
  val netMasterProducedSubBundles  = io.net.getClass.getMethods.filter( x =>
    classOf[MasterSourcedIO[Data]].isAssignableFrom(x.getReturnType)).map{ m =>
      m.invoke(io.net).asInstanceOf[MasterSourcedIO[LogicalNetworkIO[Data]]] }

  val hubClientProducedSubBundles = io.hub.map{ io => { 
    io.getClass.getMethods.filter( x =>
      classOf[ClientSourcedIO[Data]].isAssignableFrom(x.getReturnType)).map{ m =>
        m.invoke(io).asInstanceOf[ClientSourcedIO[LogicalNetworkIO[Data]]] }}}.transpose
  val hubMasterProducedSubBundles = io.hub.map{ io => {
    io.getClass.getMethods.filter( x =>
      classOf[MasterSourcedIO[Data]].isAssignableFrom(x.getReturnType)).map{ m =>
        m.invoke(io).asInstanceOf[MasterSourcedIO[LogicalNetworkIO[Data]]] }}}.transpose

  hubMasterProducedSubBundles.zip(netMasterProducedSubBundles).foreach{ case(hub, net) => {
    net.bits.header.src := UFix(0)
    net.bits.header.dst := Vec(hub.map(_.valid)){Bool()}.indexWhere{s: Bool => s}
    net.bits.payload := hub(0).bits.payload
    net.valid := hub.map(_.valid).fold(Bool(false))(_||_)
    hub.foreach( _.ready := net.ready) 
  }}
  hubClientProducedSubBundles.zip(netClientProducedSubBundles).foreach{ case(hub, net) => {
    hub.foreach(_.bits.header := net.bits.header)
    hub.zipWithIndex.foreach{ case(h,i) => h.valid := (net.bits.header.src === UFix(i)) && net.valid }
    hub.foreach(_.bits.payload := net.bits.payload)
    net.ready := hub.map(_.ready).fold(Bool(false))(_||_)
  }}
}

abstract class CoherenceHub(implicit conf: LogicalNetworkConfiguration) extends Component with MasterCoherenceAgent {
  val io = new Bundle {
    val tiles = Vec(conf.nTiles) { new TileLinkIO }.flip
    val incoherent = Vec(conf.nTiles) { Bool() }.asInput
    val mem = new ioMem
  }
}

class CoherenceHubNull(implicit conf: CoherenceHubConfiguration) extends CoherenceHub()(conf.ln)
{
  val co = conf.co.asInstanceOf[ThreeStateIncoherence]

  val acquire = io.tiles(0).acquire
  val is_write = acquire.bits.payload.a_type === co.acquireWriteback
  acquire.ready := io.mem.req_cmd.ready && !(is_write && io.mem.resp.valid) //stall write req/resp to handle previous read resp
  io.mem.req_cmd.valid   := acquire.valid && !(is_write && io.mem.resp.valid)
  io.mem.req_cmd.bits.rw    := is_write
  io.mem.req_cmd.bits.tag   := acquire.bits.payload.client_xact_id
  io.mem.req_cmd.bits.addr  := acquire.bits.payload.addr
  io.mem.req_data <> io.tiles(0).acquire_data

  val grant = io.tiles(0).grant
  grant.bits.payload.g_type := Mux(io.mem.resp.valid, co.grantData, co.grantAck)
  grant.bits.payload.client_xact_id := Mux(io.mem.resp.valid, io.mem.resp.bits.tag, acquire.bits.payload.client_xact_id)
  grant.bits.payload.master_xact_id := UFix(0) // don't care
  grant.bits.payload.data := io.mem.resp.bits.data
  grant.bits.payload.require_ack := Bool(true)
  grant.valid := io.mem.resp.valid || acquire.valid && is_write && io.mem.req_cmd.ready

  io.tiles(0).abort.valid := Bool(false)
  io.tiles(0).grant_ack.ready := Bool(true)
  io.tiles(0).probe.valid := Bool(false)
  io.tiles(0).release.ready := Bool(true)
  io.tiles(0).release_data.ready := Bool(true)
}


class CoherenceHubBroadcast(implicit conf: CoherenceHubConfiguration) extends CoherenceHub()(conf.ln)
{
  implicit val lnConf = conf.ln
  val co = conf.co
  val trackerList = (0 until NGLOBAL_XACTS).map(new XactTrackerBroadcast(_))

  val busy_arr           = Vec(NGLOBAL_XACTS){ Bool() }
  val addr_arr           = Vec(NGLOBAL_XACTS){ Bits(width=PADDR_BITS-OFFSET_BITS) }
  val init_client_id_arr   = Vec(NGLOBAL_XACTS){ Bits(width=conf.ln.idBits) }
  val client_xact_id_arr   = Vec(NGLOBAL_XACTS){ Bits(width=CLIENT_XACT_ID_BITS) }
  val a_type_arr         = Vec(NGLOBAL_XACTS){ Bits(width=ACQUIRE_TYPE_MAX_BITS) }
  val sh_count_arr       = Vec(NGLOBAL_XACTS){ Bits(width=conf.ln.idBits) }
  val send_grant_ack_arr = Vec(NGLOBAL_XACTS){ Bool() }

  val do_free_arr        = Vec(NGLOBAL_XACTS){ Bool() }
  val release_cnt_dec_arr  = VecBuf(NGLOBAL_XACTS){ Vec(conf.ln.nTiles){ Bool()}  }
  val probe_cnt_inc_arr  = VecBuf(NGLOBAL_XACTS){ Vec(conf.ln.nTiles){ Bool()}  }
  val sent_grant_ack_arr = Vec(NGLOBAL_XACTS){  Bool() }
  val p_data_client_id_arr = Vec(NGLOBAL_XACTS){  Bits(width=conf.ln.idBits) }
  val p_data_valid_arr   = Vec(NGLOBAL_XACTS){  Bool() }

  for( i <- 0 until NGLOBAL_XACTS) {
    val t = trackerList(i).io
    busy_arr(i)           := t.busy
    addr_arr(i)           := t.addr
    init_client_id_arr(i)   := t.init_client_id
    client_xact_id_arr(i)   := t.client_xact_id
    a_type_arr(i)         := t.a_type
    sh_count_arr(i)       := t.sharer_count
    send_grant_ack_arr(i) := t.send_grant_ack
    t.grant_ack         := do_free_arr(i)
    t.p_data.bits.client_id := p_data_client_id_arr(i)
    t.p_data.valid        := p_data_valid_arr(i)
    t.release_cnt_dec       := release_cnt_dec_arr(i).toBits
    t.probe_cnt_inc       := probe_cnt_inc_arr(i).toBits
    t.tile_incoherent     := io.incoherent.toBits
    t.sent_grant_ack      := sent_grant_ack_arr(i)
    do_free_arr(i)        := Bool(false)
    sent_grant_ack_arr(i) := Bool(false)
    p_data_client_id_arr(i) := Bits(0, width = conf.ln.idBits)
    p_data_valid_arr(i)   := Bool(false)
    for( j <- 0 until conf.ln.nTiles) {
      release_cnt_dec_arr(i)(j) := Bool(false)    
      probe_cnt_inc_arr(i)(j) := Bool(false)
    }
  }

  val release_data_dep_list = List.fill(conf.ln.nTiles)((new Queue(NGLOBAL_XACTS)){new TrackerDependency}) // depth must >= NPRIMARY
  val acquire_data_dep_list = List.fill(conf.ln.nTiles)((new Queue(NGLOBAL_XACTS)){new TrackerDependency}) // depth should >= NPRIMARY

  // Free finished transactions
  for( j <- 0 until conf.ln.nTiles ) {
    val ack = io.tiles(j).grant_ack
    when (ack.valid) {
      do_free_arr(ack.bits.payload.master_xact_id) := Bool(true)
    }
    ack.ready := Bool(true)
  }

  // Reply to initial requestor
  // Forward memory responses from mem to tile or arbitrate to  ack
  val mem_idx = io.mem.resp.bits.tag
  val ack_idx = PriorityEncoder(send_grant_ack_arr.toBits)
  for( j <- 0 until conf.ln.nTiles ) {
    val rep = io.tiles(j).grant
    rep.bits.payload.g_type := UFix(0)
    rep.bits.payload.client_xact_id := UFix(0)
    rep.bits.payload.master_xact_id := UFix(0)
    rep.bits.payload.data := io.mem.resp.bits.data
    rep.bits.payload.require_ack := Bool(true)
    rep.valid := Bool(false)
    when(io.mem.resp.valid && (UFix(j) === init_client_id_arr(mem_idx))) {
      rep.bits.payload.g_type := co.getGrantType(a_type_arr(mem_idx), sh_count_arr(mem_idx))
      rep.bits.payload.client_xact_id := client_xact_id_arr(mem_idx)
      rep.bits.payload.master_xact_id := mem_idx
      rep.valid := Bool(true)
    } . otherwise {
      rep.bits.payload.g_type := co.getGrantType(a_type_arr(ack_idx), sh_count_arr(ack_idx))
      rep.bits.payload.client_xact_id := client_xact_id_arr(ack_idx)
      rep.bits.payload.master_xact_id := ack_idx
      when (UFix(j) === init_client_id_arr(ack_idx)) {
        rep.valid := send_grant_ack_arr.toBits.orR
        sent_grant_ack_arr(ack_idx) := rep.ready
      }
    }
  }
  io.mem.resp.ready  := io.tiles(init_client_id_arr(mem_idx)).grant.ready

  // Create an arbiter for the one memory port
  // We have to arbitrate between the different trackers' memory requests
  // and once we have picked a request, get the right write data
  val mem_req_cmd_arb = (new Arbiter(NGLOBAL_XACTS)) { new MemReqCmd() }
  val mem_req_data_arb = (new LockingArbiter(NGLOBAL_XACTS)) { new MemData() }
  for( i <- 0 until NGLOBAL_XACTS ) {
    mem_req_cmd_arb.io.in(i)    <> trackerList(i).io.mem_req_cmd
    mem_req_data_arb.io.in(i)   <> trackerList(i).io.mem_req_data
    mem_req_data_arb.io.lock(i) <> trackerList(i).io.mem_req_lock
  }
  io.mem.req_cmd  <> Queue(mem_req_cmd_arb.io.out)
  io.mem.req_data <> Queue(mem_req_data_arb.io.out)
  
  // Handle probe replies, which may or may not have data
  for( j <- 0 until conf.ln.nTiles ) {
    val release = io.tiles(j).release
    val release_data = io.tiles(j).release_data
    val idx = release.bits.payload.master_xact_id
    val pop_releases = trackerList.map(_.io.pop_release(j).toBool)
    val do_pop = foldR(pop_releases)(_ || _)
    release.ready := Bool(true)
    release_data_dep_list(j).io.enq.valid := release.valid && co.messageHasData(release.bits.payload)
    release_data_dep_list(j).io.enq.bits.master_xact_id := release.bits.payload.master_xact_id
    release_data.ready := foldR(trackerList.map(_.io.pop_release_data(j)))(_ || _)
    when (release.valid && co.messageHasData(release.bits.payload)) {
      p_data_valid_arr(idx) := Bool(true)
      p_data_client_id_arr(idx) := UFix(j)
    }
    release_data_dep_list(j).io.deq.ready := foldR(trackerList.map(_.io.pop_release_dep(j).toBool))(_||_)
  }
  for( i <- 0 until NGLOBAL_XACTS ) {
    trackerList(i).io.release_data.valid := io.tiles(trackerList(i).io.release_client_id).release_data.valid
    trackerList(i).io.release_data.bits := io.tiles(trackerList(i).io.release_client_id).release_data.bits.payload

    trackerList(i).io.release_data_dep.valid := MuxLookup(trackerList(i).io.release_client_id, release_data_dep_list(0).io.deq.valid, (0 until conf.ln.nTiles).map( j => UFix(j) -> release_data_dep_list(j).io.deq.valid))
    trackerList(i).io.release_data_dep.bits := MuxLookup(trackerList(i).io.release_client_id, release_data_dep_list(0).io.deq.bits, (0 until conf.ln.nTiles).map( j => UFix(j) -> release_data_dep_list(j).io.deq.bits))

    for( j <- 0 until conf.ln.nTiles) {
      val release = io.tiles(j).release
      release_cnt_dec_arr(i)(j) := release.valid && (release.bits.payload.master_xact_id === UFix(i))
    }
  }

  // Nack conflicting transaction init attempts
  val s_idle :: s_abort_drain :: s_abort_send :: Nil = Enum(3){ UFix() }
  val abort_state_arr = Vec(conf.ln.nTiles) { Reg(resetVal = s_idle) }
  val want_to_abort_arr = Vec(conf.ln.nTiles) { Bool() }
  for( j <- 0 until conf.ln.nTiles ) {
    val acquire = io.tiles(j).acquire
    val acquire_data = io.tiles(j).acquire_data
    val x_abort  = io.tiles(j).abort
    val abort_cnt = Reg(resetVal = UFix(0, width = log2Up(REFILL_CYCLES)))
    val conflicts = Vec(NGLOBAL_XACTS) { Bool() }
    for( i <- 0 until NGLOBAL_XACTS) {
      val t = trackerList(i).io
      conflicts(i) := t.busy && acquire.valid && co.isCoherenceConflict(t.addr, acquire.bits.payload.addr)
    }
    x_abort.bits.payload.client_xact_id := acquire.bits.payload.client_xact_id
    want_to_abort_arr(j) := acquire.valid && (conflicts.toBits.orR || busy_arr.toBits.andR || (!acquire_data_dep_list(j).io.enq.ready && co.messageHasData(acquire.bits.payload)))
    
    x_abort.valid := Bool(false)
    switch(abort_state_arr(j)) {
      is(s_idle) {
        when(want_to_abort_arr(j)) {
          when(co.messageHasData(acquire.bits.payload)) {
            abort_state_arr(j) := s_abort_drain
          } . otherwise {
            abort_state_arr(j) := s_abort_send
          }
        }
      }
      is(s_abort_drain) { // raises acquire_data.ready below
        when(acquire_data.valid) {
          abort_cnt := abort_cnt + UFix(1)
          when(abort_cnt === ~UFix(0, width = log2Up(REFILL_CYCLES))) {
            abort_state_arr(j) := s_abort_send
          }
        }
      }
      is(s_abort_send) { // nothing is dequeued for now
        x_abort.valid := Bool(true)
        when(x_abort.ready) { // raises acquire.ready below
          abort_state_arr(j) := s_idle
        }
      }
    }
  }
  
  // Handle transaction initiation requests
  // Only one allocation per cycle
  // Init requests may or may not have data
  val alloc_arb = (new Arbiter(NGLOBAL_XACTS)) { Bool() }
  val init_arb = (new Arbiter(conf.ln.nTiles)) { new TrackerAllocReq }
  for( i <- 0 until NGLOBAL_XACTS ) {
    alloc_arb.io.in(i).valid := !trackerList(i).io.busy
    trackerList(i).io.can_alloc := alloc_arb.io.in(i).ready
    trackerList(i).io.alloc_req.bits := init_arb.io.out.bits
    trackerList(i).io.alloc_req.valid := init_arb.io.out.valid

    trackerList(i).io.acquire_data.bits := io.tiles(trackerList(i).io.init_client_id).acquire_data.bits.payload
    trackerList(i).io.acquire_data.valid := io.tiles(trackerList(i).io.init_client_id).acquire_data.valid
    trackerList(i).io.acquire_data_dep.bits := MuxLookup(trackerList(i).io.init_client_id, acquire_data_dep_list(0).io.deq.bits, (0 until conf.ln.nTiles).map( j => UFix(j) -> acquire_data_dep_list(j).io.deq.bits))
    trackerList(i).io.acquire_data_dep.valid := MuxLookup(trackerList(i).io.init_client_id, acquire_data_dep_list(0).io.deq.valid, (0 until conf.ln.nTiles).map( j => UFix(j) -> acquire_data_dep_list(j).io.deq.valid))
  }
  for( j <- 0 until conf.ln.nTiles ) {
    val acquire = io.tiles(j).acquire
    val acquire_data = io.tiles(j).acquire_data
    val acquire_data_dep = acquire_data_dep_list(j).io.deq
    val x_abort = io.tiles(j).abort
    init_arb.io.in(j).valid := (abort_state_arr(j) === s_idle) && !want_to_abort_arr(j) && acquire.valid
    init_arb.io.in(j).bits.acquire := acquire.bits.payload
    init_arb.io.in(j).bits.client_id := UFix(j)
    val pop_acquires = trackerList.map(_.io.pop_acquire(j).toBool)
    val do_pop = foldR(pop_acquires)(_||_)
    acquire_data_dep_list(j).io.enq.valid := do_pop && co.messageHasData(acquire.bits.payload) && (abort_state_arr(j) === s_idle) 
    acquire_data_dep_list(j).io.enq.bits.master_xact_id := OHToUFix(pop_acquires)
    acquire.ready := (x_abort.valid && x_abort.ready) || do_pop
    acquire_data.ready := (abort_state_arr(j) === s_abort_drain) || foldR(trackerList.map(_.io.pop_acquire_data(j).toBool))(_||_)
    acquire_data_dep.ready := foldR(trackerList.map(_.io.pop_acquire_dep(j).toBool))(_||_)
  }
  
  alloc_arb.io.out.ready := init_arb.io.out.valid

  // Handle probe request generation
  // Must arbitrate for each request port
  val probe_arb_arr = List.fill(conf.ln.nTiles)((new Arbiter(NGLOBAL_XACTS)) { new Probe() })
  for( j <- 0 until conf.ln.nTiles ) {
    for( i <- 0 until NGLOBAL_XACTS ) {
      val t = trackerList(i).io
      probe_arb_arr(j).io.in(i).bits :=  t.probe.bits
      probe_arb_arr(j).io.in(i).valid := t.probe.valid && t.push_probe(j)
      probe_cnt_inc_arr(i)(j) := probe_arb_arr(j).io.in(i).ready
    }
    FIFOedLogicalNetworkIOWrapper(probe_arb_arr(j).io.out) <> io.tiles(j).probe
  }

}

abstract class CoherenceAgent(implicit conf: LogicalNetworkConfiguration) extends Component with MasterCoherenceAgent {
  val io = new Bundle {
    val network = (new TileLinkIO).flip
    val incoherent = Vec(conf.nTiles) { Bool() }.asInput
    val mem = new ioMem
  }
}

class L2CoherenceAgent(implicit conf: CoherenceHubConfiguration) extends CoherenceAgent()(conf.ln)
{
  implicit val lnConf = conf.ln
  val co = conf.co
  val trackerList = (0 until NGLOBAL_XACTS).map(new XactTracker(_))
  val release_data_dep_q = (new Queue(NGLOBAL_XACTS)){new TrackerDependency} // depth must >= NPRIMARY
  val acquire_data_dep_q = (new Queue(NGLOBAL_XACTS)){new TrackerDependency} // depth should >= NPRIMARY
  
  for( i <- 0 until NGLOBAL_XACTS ) {
    val t = trackerList(i)
    t.io.tile_incoherent := io.incoherent.toBits
    t.io.mem_resp.valid := io.mem.resp.valid && (io.mem.resp.bits.tag === UFix(i))
    t.io.mem_resp.bits := io.mem.resp.bits
  }
  io.mem.resp.ready := trackerList.map(_.io.mem_resp.ready).reduce(_||_)

  // Handle transaction initiation requests
  // Only one allocation per cycle
  // Init requests may or may not have data
  val acquire = io.network.acquire
  val acquire_data = io.network.acquire_data
  val x_abort = io.network.abort
  val x_dep_deq = acquire_data_dep_q.io.deq
  val s_idle :: s_abort_drain :: s_abort_send :: Nil = Enum(3){ UFix() }
  val abort_state = Reg(resetVal = s_idle)
  val abort_cnt = Reg(resetVal = UFix(0, width = log2Up(REFILL_CYCLES)))
  val any_conflict = trackerList.map(_.io.has_conflict).reduce(_||_)
  val all_busy = trackerList.map(_.io.busy).reduce(_&&_)
  val want_to_abort = acquire.valid && (any_conflict || all_busy || (!acquire_data_dep_q.io.enq.ready && co.messageHasData(acquire.bits.payload)))

  val alloc_arb = (new Arbiter(NGLOBAL_XACTS)) { Bool() }
  for( i <- 0 until NGLOBAL_XACTS ) {
    alloc_arb.io.in(i).valid := !trackerList(i).io.busy
    trackerList(i).io.acquire.bits := acquire.bits
    trackerList(i).io.acquire.valid := (abort_state === s_idle) && !want_to_abort && acquire.valid && alloc_arb.io.in(i).ready

    trackerList(i).io.acquire_data.bits := acquire_data.bits
    trackerList(i).io.acquire_data.valid := acquire_data.valid
    trackerList(i).io.acquire_data_dep.bits := x_dep_deq.bits
    trackerList(i).io.acquire_data_dep.valid := x_dep_deq.valid
  }
  val pop_acquire = trackerList.map(_.io.acquire.ready).reduce(_||_)
  acquire.ready := (x_abort.valid && x_abort.ready) || pop_acquire
  acquire_data.ready := (abort_state === s_abort_drain) || trackerList.map(_.io.acquire_data.ready).reduce(_||_)
  acquire_data_dep_q.io.enq.valid := pop_acquire && co.messageHasData(acquire.bits.payload) && (abort_state === s_idle) 
  acquire_data_dep_q.io.enq.bits.master_xact_id := OHToUFix(trackerList.map(_.io.acquire.ready))
  x_dep_deq.ready := trackerList.map(_.io.acquire_data_dep.ready).reduce(_||_)
  
  alloc_arb.io.out.ready := acquire.valid

  // Nack conflicting transaction init attempts
  x_abort.bits.header.dst := acquire.bits.header.src
  x_abort.bits.payload.client_xact_id := acquire.bits.payload.client_xact_id
  x_abort.valid := Bool(false)
  switch(abort_state) {
    is(s_idle) {
      when(want_to_abort) {
        abort_state := Mux( co.messageHasData(acquire.bits.payload), s_abort_drain, s_abort_send)
      }
    }
    is(s_abort_drain) { // raises acquire_data.ready below
      when(acquire_data.valid) {
        abort_cnt := abort_cnt + UFix(1)
        when(abort_cnt === ~UFix(0, width = log2Up(REFILL_CYCLES))) {
          abort_state := s_abort_send
        }
      }
    }
    is(s_abort_send) { // nothing is dequeued for now
      x_abort.valid := Bool(true)
      when(x_abort.ready) { // raises acquire.ready 
        abort_state := s_idle
      }
    }
  }

  // Handle probe request generation
  val probe_arb = (new Arbiter(NGLOBAL_XACTS)){(new LogicalNetworkIO){ new Probe }}
  for( i <- 0 until NGLOBAL_XACTS ) {
    val t = trackerList(i).io
    probe_arb.io.in(i).bits :=  t.probe.bits
    probe_arb.io.in(i).valid := t.probe.valid
    t.probe.ready := probe_arb.io.in(i).ready
  }
  io.network.probe <> probe_arb.io.out

  // Handle probe replies, which may or may not have data
  val release = io.network.release
  val release_data = io.network.release_data
  val idx = release.bits.payload.master_xact_id
  release.ready := trackerList.map(_.io.release.ready).reduce(_||_)
  release_data.ready := trackerList.map(_.io.release_data.ready).reduce(_||_)
  release_data_dep_q.io.enq.valid := release.valid && co.messageHasData(release.bits.payload)
  release_data_dep_q.io.enq.bits.master_xact_id := release.bits.payload.master_xact_id
  release_data_dep_q.io.deq.ready := trackerList.map(_.io.release_data_dep.ready).reduce(_||_)
  for( i <- 0 until NGLOBAL_XACTS ) {
    trackerList(i).io.release_data.valid := release_data.valid
    trackerList(i).io.release_data.bits := release_data.bits
    trackerList(i).io.release_data_dep.valid := release_data_dep_q.io.deq.valid
    trackerList(i).io.release_data_dep.bits := release_data_dep_q.io.deq.bits
    trackerList(i).io.release.valid := release.valid && (idx === UFix(i))
    trackerList(i).io.release.bits := release.bits 
  }

  // Reply to initial requestor
  // Forward memory responses from mem to tile or arbitrate to  ack
  val grant_arb = (new Arbiter(NGLOBAL_XACTS)){(new LogicalNetworkIO){ new Grant }}
  for( i <- 0 until NGLOBAL_XACTS ) {
    val t = trackerList(i).io
    grant_arb.io.in(i).bits :=  t.grant.bits
    grant_arb.io.in(i).valid := t.grant.valid
    t.grant.ready := grant_arb.io.in(i).ready
  }
  grant_arb.io.out.ready := Bool(false)
  io.network.grant.valid := grant_arb.io.out.valid
  io.network.grant.bits := grant_arb.io.out.bits
  grant_arb.io.out.ready := io.network.grant.ready
  when(io.mem.resp.valid) {
    io.network.grant.valid := Bool(true)
    io.network.grant.bits := Vec(trackerList.map(_.io.grant.bits)){(new LogicalNetworkIO){new Grant}}(io.mem.resp.bits.tag)
    for( i <- 0 until NGLOBAL_XACTS ) {
      trackerList(i).io.grant.ready := (io.mem.resp.bits.tag === UFix(i)) && io.network.grant.ready
    }
  }

  // Free finished transactions
  val ack = io.network.grant_ack
  for( i <- 0 until NGLOBAL_XACTS ) {
    trackerList(i).io.free := ack.valid && (ack.bits.payload.master_xact_id === UFix(i))
  }
  ack.ready := Bool(true)

  // Create an arbiter for the one memory port
  // We have to arbitrate between the different trackers' memory requests
  // and once we have picked a request, get the right write data
  val mem_req_cmd_arb = (new Arbiter(NGLOBAL_XACTS)) { new MemReqCmd() }
  val mem_req_data_arb = (new LockingArbiter(NGLOBAL_XACTS)) { new MemData() }
  for( i <- 0 until NGLOBAL_XACTS ) {
    mem_req_cmd_arb.io.in(i)    <> trackerList(i).io.mem_req_cmd
    mem_req_data_arb.io.in(i)   <> trackerList(i).io.mem_req_data
    mem_req_data_arb.io.lock(i) <> trackerList(i).io.mem_req_lock
  }
  io.mem.req_cmd  <> Queue(mem_req_cmd_arb.io.out)
  io.mem.req_data <> Queue(mem_req_data_arb.io.out)
}

class XactTracker(id: Int)(implicit conf: CoherenceHubConfiguration) extends Component {
  val co = conf.co
  implicit val ln = conf.ln
  val io = new Bundle {
    val acquire          = (new FIFOIO){(new LogicalNetworkIO) { new Acquire }}.flip
    val acquire_data     = (new FIFOIO){(new LogicalNetworkIO) { new AcquireData }}.flip
    val release           = (new FIFOIO){(new LogicalNetworkIO) { new Release }}.flip
    val release_data      = (new FIFOIO){(new LogicalNetworkIO) { new ReleaseData }}.flip
    val free            = Bool(INPUT)
    val tile_incoherent = Bits(INPUT, conf.ln.nTiles)
    val release_data_dep  = (new FIFOIO) { new TrackerDependency }.flip
    val acquire_data_dep = (new FIFOIO) { new TrackerDependency }.flip
    val mem_resp        = (new FIFOIO) { new MemResp }.flip

    val mem_req_cmd     = (new FIFOIO) { new MemReqCmd }
    val mem_req_data    = (new FIFOIO) { new MemData }
    val mem_req_lock    = Bool(OUTPUT)
    val probe           = (new FIFOIO) {(new LogicalNetworkIO) { new Probe }}
    val grant           = (new FIFOIO) {(new LogicalNetworkIO) { new Grant }}
    val busy            = Bool(OUTPUT)
    val has_conflict    = Bool(OUTPUT)
  }

  val s_idle :: s_ack :: s_mem :: s_probe :: s_busy :: Nil = Enum(5){ UFix() }
  val state = Reg(resetVal = s_idle)
  val xact  = Reg{ new Acquire }
  val init_client_id_ = Reg(resetVal = UFix(0, width = log2Up(conf.ln.nTiles)))
  //TODO: Will need id reg for merged release xacts
  val init_sharer_cnt_ = Reg(resetVal = UFix(0, width = log2Up(conf.ln.nTiles)))
  val release_count = if (conf.ln.nTiles == 1) UFix(0) else Reg(resetVal = UFix(0, width = log2Up(conf.ln.nTiles)))
  val probe_flags = Reg(resetVal = Bits(0, width = conf.ln.nTiles))
  val x_needs_read = Reg(resetVal = Bool(false))
  val acquire_data_needs_write = Reg(resetVal = Bool(false))
  val release_data_needs_write = Reg(resetVal = Bool(false))
  val x_w_mem_cmd_sent = Reg(resetVal = Bool(false))
  val p_w_mem_cmd_sent = Reg(resetVal = Bool(false))
  val mem_cnt = Reg(resetVal = UFix(0, width = log2Up(REFILL_CYCLES)))
  val mem_cnt_next = mem_cnt + UFix(1)
  val mem_cnt_max = ~UFix(0, width = log2Up(REFILL_CYCLES))
  val probe_initial_flags = Bits(width = conf.ln.nTiles)
  probe_initial_flags := Bits(0)
  if (conf.ln.nTiles > 1) {
    // issue self-probes for uncached read xacts to facilitate I$ coherence
    // TODO: this is hackish; figure out how to do it more systematically
    val probe_self = co match {
      case u: CoherencePolicyWithUncached => u.isUncachedReadTransaction(io.acquire.bits.payload)
      case _ => Bool(false)
    }
    val myflag = Mux(probe_self, Bits(0), UFixToOH(io.acquire.bits.header.src(log2Up(conf.ln.nTiles)-1,0)))
    probe_initial_flags := ~(io.tile_incoherent | myflag)
  }
  val all_grants_require_acks = Bool(true)

  io.busy := state != s_idle
  io.has_conflict := co.isCoherenceConflict(xact.addr, io.acquire.bits.payload.addr) && (state != s_idle)
  io.mem_req_cmd.valid := Bool(false)
  io.mem_req_cmd.bits.rw := Bool(false)
  io.mem_req_cmd.bits.addr := xact.addr
  io.mem_req_cmd.bits.tag := UFix(id)
  io.mem_req_data.valid := Bool(false)
  io.mem_req_data.bits.data := UFix(0)
  io.mem_req_lock := Bool(false)
  io.probe.valid := Bool(false)
  io.probe.bits.payload.p_type := co.getProbeType(xact.a_type, UFix(0))
  io.probe.bits.payload.master_xact_id  := UFix(id)
  io.probe.bits.payload.addr := xact.addr
  io.probe.bits.header.dst := UFix(0)
  io.grant.bits.payload.data := io.mem_resp.bits.data
  io.grant.bits.payload.g_type := co.getGrantType(xact.a_type, init_sharer_cnt_)
  io.grant.bits.payload.client_xact_id := xact.client_xact_id
  io.grant.bits.payload.master_xact_id := UFix(id)
  io.grant.bits.payload.require_ack := all_grants_require_acks
  io.grant.bits.header.dst := init_client_id_
  io.grant.valid := (io.mem_resp.valid && (UFix(id) === io.mem_resp.bits.tag)) 
  io.acquire.ready := Bool(false)
  io.acquire_data.ready := Bool(false)
  io.acquire_data_dep.ready := Bool(false)  
  io.release.ready := Bool(false)
  io.release_data.ready := Bool(false)
  io.release_data_dep.ready := Bool(false)  
  io.mem_resp.ready := io.grant.ready

  switch (state) {
    is(s_idle) {
      when( io.acquire.valid ) {
        xact := io.acquire.bits.payload
        init_client_id_ := io.acquire.bits.header.src
        init_sharer_cnt_ := UFix(conf.ln.nTiles) // TODO: Broadcast only
        acquire_data_needs_write := co.messageHasData(io.acquire.bits.payload)
        x_needs_read := co.needsMemRead(io.acquire.bits.payload.a_type, UFix(0))
        probe_flags := probe_initial_flags
        mem_cnt := UFix(0)
        p_w_mem_cmd_sent := Bool(false)
        x_w_mem_cmd_sent := Bool(false)
        io.acquire.ready := Bool(true)
        if(conf.ln.nTiles > 1) {
          release_count := PopCount(probe_initial_flags)
          state := Mux(probe_initial_flags.orR, s_probe, s_mem)
        } else state := s_mem
      }
    }
    is(s_probe) {
      val curr_p_id = PriorityEncoder(probe_flags)
      when(probe_flags.orR) {
        io.probe.valid := Bool(true)
        io.probe.bits.header.dst := curr_p_id 
      }
      when(io.probe.ready) {
        probe_flags := probe_flags & ~(UFixToOH(curr_p_id))
      }
      when(io.release.valid) {
        io.release.ready := Bool(true)
        if(conf.ln.nTiles > 1) release_count := release_count - UFix(1)
        when(release_count === UFix(1)) {
          state := s_mem
        }
        release_data_needs_write := co.messageHasData(io.release.bits.payload)
      }
    }
    is(s_mem) {
      when (release_data_needs_write) {
        doMemReqWrite(io.mem_req_cmd, 
                      io.mem_req_data, 
                      io.mem_req_lock, 
                      io.release_data, 
                      release_data_needs_write, 
                      p_w_mem_cmd_sent, 
                      io.release_data_dep.ready, 
                      io.release_data_dep.valid && (io.release_data_dep.bits.master_xact_id === UFix(id)))
      } . elsewhen(acquire_data_needs_write) {
        doMemReqWrite(io.mem_req_cmd, 
                      io.mem_req_data, 
                      io.mem_req_lock, 
                      io.acquire_data, 
                      acquire_data_needs_write, 
                      x_w_mem_cmd_sent, 
                      io.acquire_data_dep.ready,
                      io.acquire_data_dep.valid && (io.acquire_data_dep.bits.master_xact_id === UFix(id)))
      } . elsewhen (x_needs_read) {    
        doMemReqRead(io.mem_req_cmd, x_needs_read)
      } . otherwise { 
        state := Mux(co.needsAckReply(xact.a_type, UFix(0)), s_ack, 
                  Mux(all_grants_require_acks, s_busy, s_idle))
      }
    }
    is(s_ack) {
      io.grant.valid := Bool(true)
      when(io.grant.ready) { state := Mux(all_grants_require_acks, s_busy, s_idle) }
    }
    is(s_busy) { // Nothing left to do but wait for transaction to complete
      when (io.free) {
        state := s_idle
      }
    }
  }

  def doMemReqWrite[T <: Data](req_cmd: FIFOIO[MemReqCmd], req_data: FIFOIO[MemData], lock: Bool,  data: FIFOIO[LogicalNetworkIO[T]], trigger: Bool, cmd_sent: Bool, pop_dep: Bool, at_front_of_dep_queue: Bool) {
    req_cmd.bits.rw := Bool(true)
    req_data.bits := data.bits.payload
    when(req_cmd.ready && req_cmd.valid) {
      cmd_sent := Bool(true)
    }
    when (at_front_of_dep_queue) {
      req_cmd.valid := !cmd_sent && req_data.ready && data.valid
      lock := data.valid || cmd_sent
      when (req_cmd.ready || cmd_sent) {
        req_data.valid := data.valid
        when(req_data.ready) {
          data.ready:= Bool(true)
          when (data.valid) {
            mem_cnt  := mem_cnt_next
            when(mem_cnt === UFix(REFILL_CYCLES-1)) {
              pop_dep := Bool(true)
              trigger := Bool(false)
            }
          }
        }
      }
    }
  }

  def doMemReqRead(req_cmd: FIFOIO[MemReqCmd], trigger: Bool) {
    req_cmd.valid := Bool(true)
    req_cmd.bits.rw := Bool(false)
    when(req_cmd.ready) {
      trigger := Bool(false)
    }
  }
}