gem5/src/mem/protocol/MOESI_CMP_directory-dma.sm

machine(DMA, "DMA Controller") 
: int request_latency,
  int response_latency
{
  
  MessageBuffer goo1, network="From", virtual_network="0", ordered="false";
  MessageBuffer goo2, network="From", virtual_network="1", ordered="false";
  MessageBuffer responseFromDir, network="From", virtual_network="2", ordered="false";

  MessageBuffer foo1, network="To", virtual_network="0", ordered="false";
  MessageBuffer reqToDir, network="To", virtual_network="1", ordered="false";
  MessageBuffer respToDir, network="To", virtual_network="2", ordered="false";
  
  enumeration(State, desc="DMA states", default="DMA_State_READY") {
    READY, desc="Ready to accept a new request";
    BUSY_RD,  desc="Busy: currently processing a request";
    BUSY_WR,  desc="Busy: currently processing a request";
  }
  
  enumeration(Event, desc="DMA events") {
    ReadRequest,  desc="A new read request";
    WriteRequest, desc="A new write request";
    Data,         desc="Data from a DMA memory read";
    DMA_Ack,      desc="DMA write to memory completed";
    Inv_Ack,      desc="Invalidation Ack from a sharer";
    All_Acks,     desc="All acks received";
  }

  structure(TBE, desc="...") {
    Address address, desc="Physical address";
    int NumAcks, default="0", desc="Number of Acks pending";
    DataBlock DataBlk, desc="Data";
  }

  external_type(DMASequencer) {
    void ackCallback();
    void dataCallback(DataBlock);
  }

  external_type(TBETable) {
    TBE lookup(Address);
    void allocate(Address);
    void deallocate(Address);
    bool isPresent(Address);
  }

  MessageBuffer mandatoryQueue, ordered="false";
  MessageBuffer triggerQueue, ordered="true";
  DMASequencer dma_sequencer, factory='RubySystem::getDMASequencer(m_cfg["dma_sequencer"])';
  TBETable TBEs, template_hack="<DMA_TBE>";
  State cur_state;

  State getState(Address addr) {
    return cur_state;
  }
  void setState(Address addr, State state) {
  cur_state := state;
  }

  out_port(reqToDirectory_out, RequestMsg, reqToDir, desc="...");
  out_port(respToDirectory_out, ResponseMsg, respToDir, desc="...");
  out_port(foo1_out, ResponseMsg, foo1, desc="...");
  out_port(triggerQueue_out, TriggerMsg, triggerQueue, desc="...");

  in_port(goo1_in, RequestMsg, goo1) {
    if (goo1_in.isReady()) {
      peek(goo1_in, RequestMsg) {
        assert(false);
      }
    }
  }
  
  in_port(goo2_in, RequestMsg, goo2) {
    if (goo2_in.isReady()) {
      peek(goo2_in, RequestMsg) {
        assert(false);
      }
    }
  }

  in_port(dmaRequestQueue_in, SequencerMsg, mandatoryQueue, desc="...") {
    if (dmaRequestQueue_in.isReady()) {
      peek(dmaRequestQueue_in, SequencerMsg) {
        if (in_msg.Type == SequencerRequestType:LD ) {
          trigger(Event:ReadRequest, in_msg.PhysicalAddress);
        } else if (in_msg.Type == SequencerRequestType:ST) {
          trigger(Event:WriteRequest, in_msg.PhysicalAddress);
        } else {
          error("Invalid request type");
        }
      }
    }
  }

  in_port(dmaResponseQueue_in, ResponseMsg, responseFromDir, desc="...") {
    if (dmaResponseQueue_in.isReady()) {
      peek( dmaResponseQueue_in, ResponseMsg) {
        if (in_msg.Type == CoherenceResponseType:DMA_ACK) {
          trigger(Event:DMA_Ack, in_msg.Address);
        } else if (in_msg.Type == CoherenceResponseType:DATA_EXCLUSIVE) {
          trigger(Event:Data, in_msg.Address);
        } else if (in_msg.Type == CoherenceResponseType:ACK) {
          trigger(Event:Inv_Ack, in_msg.Address);
        } else {
          error("Invalid response type");
        }
      }
    }
  }

  // Trigger Queue
  in_port(triggerQueue_in, TriggerMsg, triggerQueue) {
    if (triggerQueue_in.isReady()) {
      peek(triggerQueue_in, TriggerMsg) {
        if (in_msg.Type == TriggerType:ALL_ACKS) {
          trigger(Event:All_Acks, in_msg.Address);
        } else {
          error("Unexpected message");
        }
      }
    }
  }

  action(s_sendReadRequest, "s", desc="Send a DMA read request to memory") {
    peek(dmaRequestQueue_in, SequencerMsg) {
      enqueue(reqToDirectory_out, RequestMsg, latency=request_latency) {
        out_msg.Address := address;
        out_msg.Type := CoherenceRequestType:DMA_READ;
        out_msg.DataBlk := in_msg.DataBlk;
        out_msg.Len := in_msg.Len;
        out_msg.Destination.add(map_Address_to_Directory(address));
        out_msg.Requestor := machineID;
        out_msg.MessageSize := MessageSizeType:Writeback_Control;
      }
    }
  }

  action(s_sendWriteRequest, "\s", desc="Send a DMA write request to memory") {
    peek(dmaRequestQueue_in, SequencerMsg) {
      enqueue(reqToDirectory_out, RequestMsg, latency=request_latency) {
          out_msg.Address := address;
          out_msg.Type := CoherenceRequestType:DMA_WRITE;
          out_msg.DataBlk := in_msg.DataBlk;
          out_msg.Len := in_msg.Len;
          out_msg.Destination.add(map_Address_to_Directory(address));
          out_msg.Requestor := machineID;
          out_msg.MessageSize := MessageSizeType:Writeback_Control;
        }
      }
  }

  action(a_ackCallback, "a", desc="Notify dma controller that write request completed") {
      dma_sequencer.ackCallback();
  }

  action(o_checkForCompletion, "o", desc="Check if we have received all the messages required for completion") {
    if (TBEs[address].NumAcks == 0) {
      enqueue(triggerQueue_out, TriggerMsg) {
        out_msg.Address := address;
        out_msg.Type := TriggerType:ALL_ACKS;
      }
    }
  }

  action(u_updateAckCount, "u", desc="Update ack count") {
    peek(dmaResponseQueue_in, ResponseMsg) {
      TBEs[address].NumAcks := TBEs[address].NumAcks - in_msg.Acks;
    }
  }

  action( u_sendExclusiveUnblockToDir, "\u", desc="send exclusive unblock to directory") {
    enqueue(respToDirectory_out, ResponseMsg, latency=response_latency) {
      out_msg.Address := address;
      out_msg.Type := CoherenceResponseType:UNBLOCK_EXCLUSIVE;
      out_msg.Destination.add(map_Address_to_Directory(address));
      out_msg.MessageSize := MessageSizeType:Writeback_Control;
    }
  }

  action(p_popRequestQueue, "p", desc="Pop request queue") {
    dmaRequestQueue_in.dequeue();
  }

  action(p_popResponseQueue, "\p", desc="Pop request queue") {
    dmaResponseQueue_in.dequeue();
  }

  action(p_popTriggerQueue, "pp", desc="Pop trigger queue") {
    triggerQueue_in.dequeue();
  }

  action(t_updateTBEData, "t", desc="Update TBE Data") {
    peek(dmaResponseQueue_in, ResponseMsg) {
      TBEs[address].DataBlk := in_msg.DataBlk;
    }
  }

  action(d_dataCallbackFromTBE, "/d", desc="data callback with data from TBE") {
    dma_sequencer.dataCallback(TBEs[address].DataBlk);
  }

  action(v_allocateTBE, "v", desc="Allocate TBE entry") {
    TBEs.allocate(address);
  }

  action(w_deallocateTBE, "w", desc="Deallocate TBE entry") {
    TBEs.deallocate(address);
  }

  action(z_stall, "z", desc="dma is busy..stall") {
    // do nothing
  }



  transition(READY, ReadRequest, BUSY_RD) {
    s_sendReadRequest;
    v_allocateTBE;
    p_popRequestQueue;
  }

  transition(BUSY_RD, Inv_Ack) {
    u_updateAckCount;
    o_checkForCompletion;
    p_popResponseQueue;
  }

  transition(BUSY_RD, Data) {
    t_updateTBEData;
    u_updateAckCount;
    o_checkForCompletion;
    p_popResponseQueue;
  }

  transition(BUSY_RD, All_Acks, READY) {
    d_dataCallbackFromTBE;
    u_sendExclusiveUnblockToDir;
    w_deallocateTBE;
    p_popTriggerQueue;
  }

  transition(READY, WriteRequest, BUSY_WR) {
    s_sendWriteRequest;
    v_allocateTBE;
    p_popRequestQueue;
  }

  transition(BUSY_WR, Inv_Ack) {
    u_updateAckCount;
    o_checkForCompletion;
    p_popResponseQueue;
  }

  transition(BUSY_WR, DMA_Ack) {
    u_updateAckCount; // actually increases
    o_checkForCompletion;
    p_popResponseQueue;
  }

  transition(BUSY_WR, All_Acks, READY) {
    a_ackCallback; 
    u_sendExclusiveUnblockToDir;
    w_deallocateTBE;
    p_popTriggerQueue;
  }
}