/*****************************************************************************

  The following code is derived, directly or indirectly, from the SystemC
  source code Copyright (c) 1996-2008 by all Contributors.
  All Rights reserved.

  The contents of this file are subject to the restrictions and limitations
  set forth in the SystemC Open Source License Version 3.0 (the "License");
  You may not use this file except in compliance with such restrictions and
  limitations. You may obtain instructions on how to receive a copy of the
  License at http://www.systemc.org/. Software distributed by Contributors
  under the License is distributed on an "AS IS" basis, WITHOUT WARRANTY OF
  ANY KIND, either express or implied. See the License for the specific
  language governing rights and limitations under the License.

 *****************************************************************************/

#ifndef __SIMPLE_AT_TARGET1_H__
#define __SIMPLE_AT_TARGET1_H__

#include "tlm.h"
#include "tlm_utils/simple_target_socket.h"
//#include <systemc>
#include <cassert>
#include <vector>
#include <queue>
//#include <iostream>

class SimpleATTarget1 : public sc_core::sc_module
{
public:
  typedef tlm::tlm_generic_payload            transaction_type;
  typedef tlm::tlm_phase                      phase_type;
  typedef tlm::tlm_sync_enum                  sync_enum_type;
  typedef tlm_utils::simple_target_socket<SimpleATTarget1> target_socket_type;

public:
  target_socket_type socket;

public:
  SC_HAS_PROCESS(SimpleATTarget1);
  SimpleATTarget1(sc_core::sc_module_name name) :
    sc_core::sc_module(name),
    socket("socket"),
    ACCEPT_DELAY(25, sc_core::SC_NS),
    RESPONSE_DELAY(100, sc_core::SC_NS)
  {
    // register nb_transport method
    socket.register_nb_transport_fw(this, &SimpleATTarget1::myNBTransport);

    SC_METHOD(endRequest)
    sensitive << mEndRequestEvent;
    dont_initialize();

    SC_METHOD(beginResponse)
    sensitive << mBeginResponseEvent;
    dont_initialize();

    SC_METHOD(endResponse)
    sensitive << mEndResponseEvent;
    dont_initialize();
  }

  //
  // Simple AT target
  // - Request is accepted after ACCEPT delay (relative to end of prev request
  //   phase)
  // - Response is started after RESPONSE delay (relative to end of prev resp
  //   phase)
  //
  sync_enum_type myNBTransport(transaction_type& trans, phase_type& phase, sc_core::sc_time& t)
  {
    if (phase == tlm::BEGIN_REQ) {
      // transactions may be kept in queue after the initiator has send END_REQ
      trans.acquire();

      sc_dt::uint64 address = trans.get_address();
      assert(address < 400);

      unsigned int& data = *reinterpret_cast<unsigned int*>(trans.get_data_ptr());
      if (trans.get_command() == tlm::TLM_WRITE_COMMAND) {
        std::cout << name() << ": Received write request: A = 0x"
                  << std::hex << (unsigned int)address << ", D = 0x"
                  << data << std::dec
                  << " @ " << sc_core::sc_time_stamp() << std::endl;

        *reinterpret_cast<unsigned int*>(&mMem[address]) = data;

      } else {
        std::cout << name() << ": Received read request: A = 0x"
                  << std::hex << (unsigned int)address << std::dec
                  << " @ " << sc_core::sc_time_stamp() << std::endl;

        data = *reinterpret_cast<unsigned int*>(&mMem[address]);
      }

      // Notify end of request phase after ACCEPT delay
      if (mEndRequestQueue.empty()) {
        mEndRequestEvent.notify(t + ACCEPT_DELAY);
      }
      mEndRequestQueue.push(&trans);

      // AT-noTA target
      // - always return false
      // - seperate call to indicate end of phase (do not update phase or t)
      return tlm::TLM_ACCEPTED;

    } else if (phase == tlm::END_RESP) {

      // response phase ends after t
      mEndResponseEvent.notify(t);

      return tlm::TLM_COMPLETED;
    }

    // Not possible
    assert(0); exit(1);
//    return tlm::TLM_COMPLETED;  //unreachable code
  }

  void endRequest()
  {
    assert(!mEndRequestQueue.empty());
    // end request phase of oldest transaction
    phase_type phase = tlm::END_REQ;
    sc_core::sc_time t = sc_core::SC_ZERO_TIME;
    transaction_type* trans = mEndRequestQueue.front();
    assert(trans);
    mEndRequestQueue.pop();
    #if ( ! NDEBUG )
    sync_enum_type r = socket->nb_transport_bw(*trans, phase, t);
    #endif /* ! NDEBUG */
    assert(r == tlm::TLM_ACCEPTED); // FIXME: initiator should return TLM_ACCEPTED?
    assert(t == sc_core::SC_ZERO_TIME); // t must be SC_ZERO_TIME

    // Notify end of request phase for next transaction after ACCEPT delay
    if (!mEndRequestQueue.empty()) {
      mEndRequestEvent.notify(ACCEPT_DELAY);
    }

    if (mResponseQueue.empty()) {
      // Start processing transaction
      // Notify begin of response phase after RESPONSE delay
      mBeginResponseEvent.notify(RESPONSE_DELAY);
    }
    mResponseQueue.push(trans);
  }

  void beginResponse()
  {
    assert(!mResponseQueue.empty());
    // start response phase of oldest transaction
    phase_type phase = tlm::BEGIN_RESP;
    sc_core::sc_time t = sc_core::SC_ZERO_TIME;
    transaction_type* trans = mResponseQueue.front();
    assert(trans);

    // Set response data
    trans->set_response_status(tlm::TLM_OK_RESPONSE);
    if (trans->get_command() == tlm::TLM_READ_COMMAND) {
       sc_dt::uint64 address = trans->get_address();
       assert(address < 400);
      *reinterpret_cast<unsigned int*>(trans->get_data_ptr()) =
        *reinterpret_cast<unsigned int*>(&mMem[address]);
    }

    switch (socket->nb_transport_bw(*trans, phase, t)) {
    case tlm::TLM_COMPLETED:
      // response phase ends after t
      mEndResponseEvent.notify(t);
      break;

    case tlm::TLM_ACCEPTED:
    case tlm::TLM_UPDATED:
     // initiator will call nb_transport to indicate end of response phase
     break;

    default:
      assert(0); exit(1);
    };
  }

  void endResponse()
  {
    assert(!mResponseQueue.empty());
    mResponseQueue.front()->release();
    mResponseQueue.pop();

    if (!mResponseQueue.empty()) {
      // Start processing next transaction
      // Notify begin of response phase after RESPONSE delay
      mBeginResponseEvent.notify(RESPONSE_DELAY);
    }
  }

private:
  const sc_core::sc_time ACCEPT_DELAY;
  const sc_core::sc_time RESPONSE_DELAY;

private:
  unsigned char mMem[400];
  std::queue<transaction_type*> mEndRequestQueue;
  sc_core::sc_event mEndRequestEvent;
  std::queue<transaction_type*> mResponseQueue;
  sc_core::sc_event mBeginResponseEvent;
  sc_core::sc_event mEndResponseEvent;
};

#endif
