/*
 * Copyright (c) 1999-2008 Mark D. Hill and David A. Wood
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met: redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer;
 * redistributions in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the distribution;
 * neither the name of the copyright holders nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

machine(Directory, "AMD Hammer-like protocol") {

  // STATES
  enumeration(State, desc="Directory states", default="Directory_State_E") {
    // Base states
    NO,             desc="Not Owner";
    O,              desc="Owner";
    E,              desc="Exclusive Owner (we can provide the data in exclusive)";
    NO_B,  "NO^B",  desc="Not Owner, Blocked";
    O_B,   "O^B",   desc="Owner, Blocked";
    WB,             desc="Blocked on a writeback";
  }

  // Events
  enumeration(Event, desc="Directory events") {
    GETX,                      desc="A GETX arrives";
    GETS,                      desc="A GETS arrives";
    PUT,                       desc="A PUT arrives"; 
    Unblock,                   desc="An unblock message arrives";
    Writeback_Clean,           desc="The final part of a PutX (no data)";
    Writeback_Dirty,           desc="The final part of a PutX (data)";
    Writeback_Exclusive_Clean, desc="The final part of a PutX (no data, exclusive)";
    Writeback_Exclusive_Dirty, desc="The final part of a PutX (data, exclusive)";
  }

  // TYPES

  // DirectoryEntry
  structure(Entry, desc="...") {
    State DirectoryState,          desc="Directory state";
    DataBlock DataBlk,             desc="data for the block";
  }

  external_type(DirectoryMemory) {
    Entry lookup(Address);
    bool isPresent(Address);
  }

  // ** OBJECTS **

  DirectoryMemory directory;

  State getState(Address addr) {
    return directory[addr].DirectoryState;
  }
  
  void setState(Address addr, State state) {
    directory[addr].DirectoryState := state;
  }
  
  // ** OUT_PORTS **
  out_port(forwardNetwork_out, RequestMsg, forwardFromDir);
  out_port(responseNetwork_out, ResponseMsg, responseFromDir);
  out_port(requestQueue_out, ResponseMsg, requestToDir); // For recycling requests
  
  // ** IN_PORTS **
  
  in_port(unblockNetwork_in, ResponseMsg, unblockToDir) {
    if (unblockNetwork_in.isReady()) {
      peek(unblockNetwork_in, ResponseMsg) {
        if (in_msg.Type == CoherenceResponseType:UNBLOCK) {
          trigger(Event:Unblock, in_msg.Address);
        } else if (in_msg.Type == CoherenceResponseType:WB_CLEAN) {
          trigger(Event:Writeback_Clean, in_msg.Address);
        } else if (in_msg.Type == CoherenceResponseType:WB_DIRTY) {
          trigger(Event:Writeback_Dirty, in_msg.Address);
        } else if (in_msg.Type == CoherenceResponseType:WB_EXCLUSIVE_CLEAN) {
          trigger(Event:Writeback_Exclusive_Clean, in_msg.Address);
        } else if (in_msg.Type == CoherenceResponseType:WB_EXCLUSIVE_DIRTY) {
          trigger(Event:Writeback_Exclusive_Dirty, in_msg.Address);
        } else {
          error("Invalid message");
        }
      }
    }
  }

  in_port(requestQueue_in, RequestMsg, requestToDir) {
    if (requestQueue_in.isReady()) {
      peek(requestQueue_in, RequestMsg) {
        if (in_msg.Type == CoherenceRequestType:GETS) {
          trigger(Event:GETS, in_msg.Address);
        } else if (in_msg.Type == CoherenceRequestType:GETX) {
          trigger(Event:GETX, in_msg.Address);
        } else if (in_msg.Type == CoherenceRequestType:PUT) {
          trigger(Event:PUT, in_msg.Address);
        } else {
          error("Invalid message");
        }
      }
    }
  }

  // Actions
  
  action(a_sendWriteBackAck, "a", desc="Send writeback ack to requestor") {
    peek(requestQueue_in, RequestMsg) {
      enqueue(forwardNetwork_out, RequestMsg, latency="DIRECTORY_LATENCY") {
        out_msg.Address := address;
        out_msg.Type := CoherenceRequestType:WB_ACK;
        out_msg.Requestor := in_msg.Requestor;
        out_msg.Destination.add(in_msg.Requestor);
        out_msg.MessageSize := MessageSizeType:Writeback_Control;
      }
    }
  }

  action(b_sendWriteBackNack, "b", desc="Send writeback nack to requestor") {
    peek(requestQueue_in, RequestMsg) {
      enqueue(forwardNetwork_out, RequestMsg, latency="DIRECTORY_LATENCY") {
        out_msg.Address := address;
        out_msg.Type := CoherenceRequestType:WB_NACK;
        out_msg.Requestor := in_msg.Requestor;
        out_msg.Destination.add(in_msg.Requestor);
        out_msg.MessageSize := MessageSizeType:Writeback_Control;
      }
    }
  }

  action(d_sendData, "d", desc="Send data to requestor") {
    peek(requestQueue_in, RequestMsg) {
      enqueue(responseNetwork_out, ResponseMsg, latency="MEMORY_LATENCY") {
        out_msg.Address := address;
        out_msg.Type := CoherenceResponseType:DATA;
        out_msg.Sender := id;
        out_msg.Destination.add(in_msg.Requestor);
        out_msg.DataBlk := directory[in_msg.Address].DataBlk;
        out_msg.Dirty := false; // By definition, the block is now clean
        out_msg.Acks := 1;
        out_msg.MessageSize := MessageSizeType:Response_Data;
      }
    }
  }

  action(dd_sendExclusiveData, "\d", desc="Send exclusive data to requestor") {
    peek(requestQueue_in, RequestMsg) {
      enqueue(responseNetwork_out, ResponseMsg, latency="MEMORY_LATENCY") {
        out_msg.Address := address;
        out_msg.Type := CoherenceResponseType:DATA_EXCLUSIVE;
        out_msg.Sender := id;
        out_msg.Destination.add(in_msg.Requestor);
        out_msg.DataBlk := directory[in_msg.Address].DataBlk;
        out_msg.Dirty := false; // By definition, the block is now clean
        out_msg.Acks := 1;
        out_msg.MessageSize := MessageSizeType:Response_Data;
      }
    }
  }

  action(f_forwardRequest, "f", desc="Forward requests") {
    if (numberOfNodes() > 1) {
      peek(requestQueue_in, RequestMsg) {
        enqueue(forwardNetwork_out, RequestMsg, latency="DIRECTORY_LATENCY") {
          out_msg.Address := address;
          out_msg.Type := in_msg.Type;
          out_msg.Requestor := in_msg.Requestor;
          out_msg.Destination.broadcast(); // Send to everyone, but...
          out_msg.Destination.remove(in_msg.Requestor); // Don't include the original requestor
          out_msg.MessageSize := MessageSizeType:Forwarded_Control;
        }
      }
    }
  }

  action(i_popIncomingRequestQueue, "i", desc="Pop incoming request queue") {
    requestQueue_in.dequeue();
  }

  action(j_popIncomingUnblockQueue, "j", desc="Pop incoming unblock queue") {
    unblockNetwork_in.dequeue();
  }

  action(l_writeDataToMemory, "l", desc="Write PUTX/PUTO data to memory") {
    peek(unblockNetwork_in, ResponseMsg) {
      assert(in_msg.Dirty);
      assert(in_msg.MessageSize == MessageSizeType:Writeback_Data);
      directory[in_msg.Address].DataBlk := in_msg.DataBlk;
      DEBUG_EXPR(in_msg.Address);
      DEBUG_EXPR(in_msg.DataBlk);
    }
  }

  action(ll_checkIncomingWriteback, "\l", desc="Check PUTX/PUTO response message") {
    peek(unblockNetwork_in, ResponseMsg) {
      assert(in_msg.Dirty == false);
      assert(in_msg.MessageSize == MessageSizeType:Writeback_Control);

      // NOTE: The following check would not be valid in a real
      // implementation.  We include the data in the "dataless"
      // message so we can assert the clean data matches the datablock
      // in memory
      assert(directory[in_msg.Address].DataBlk == in_msg.DataBlk);
    }
  }

  //  action(z_stall, "z", desc="Cannot be handled right now.") {
    // Special name recognized as do nothing case
  //  }

  action(zz_recycleRequest, "\z", desc="Recycle the request queue") {
    requestQueue_in.recycle();
  }

  // TRANSITIONS

  transition(E, GETX, NO_B) {
    dd_sendExclusiveData;
    f_forwardRequest;
    i_popIncomingRequestQueue;
  }

  transition(E, GETS, NO_B) {
    dd_sendExclusiveData;
    f_forwardRequest;
    i_popIncomingRequestQueue;
  }

  // 
  transition(O, GETX, NO_B) {
    d_sendData;
    f_forwardRequest;
    i_popIncomingRequestQueue;
  }

  transition(O, GETS, O_B) {
    d_sendData;
    f_forwardRequest;
    i_popIncomingRequestQueue;
  }

  //
  transition(NO, GETX, NO_B) {
    f_forwardRequest;
    i_popIncomingRequestQueue;
  }

  transition(NO, GETS, NO_B) {
    f_forwardRequest;
    i_popIncomingRequestQueue;
  }

  transition(NO, PUT, WB) {
    a_sendWriteBackAck;
    i_popIncomingRequestQueue;
  }

  transition({O, E}, PUT) {
    b_sendWriteBackNack;
    i_popIncomingRequestQueue;
  }

  // Blocked states
  transition({NO_B, O_B, WB}, {GETS, GETX, PUT}) {
    zz_recycleRequest;
  }

  transition(NO_B, Unblock, NO) {
    j_popIncomingUnblockQueue;
  }

  transition(O_B, Unblock, O) {
    j_popIncomingUnblockQueue;
  }

  // WB
  transition(WB, Writeback_Dirty, O) {
    l_writeDataToMemory;
    j_popIncomingUnblockQueue;
  }

  transition(WB, Writeback_Exclusive_Dirty, E) {
    l_writeDataToMemory;
    j_popIncomingUnblockQueue;
  }

  transition(WB, Writeback_Clean, O) {
    ll_checkIncomingWriteback;
    j_popIncomingUnblockQueue;
  }

  transition(WB, Writeback_Exclusive_Clean, E) {
    ll_checkIncomingWriteback;
    j_popIncomingUnblockQueue;
  }

  transition(WB, Unblock, NO) {
    j_popIncomingUnblockQueue;
  }
}