xref: /gem5/src/systemc/tests/include/SimpleATTarget2.h

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#ifndef __SIMPLE_AT_TARGET2_H__
#define __SIMPLE_AT_TARGET2_H__

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

class SimpleATTarget2 : 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<SimpleATTarget2> target_socket_type;

public:
  target_socket_type socket;

public:
  SC_HAS_PROCESS(SimpleATTarget2);
  SimpleATTarget2(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, &SimpleATTarget2::myNBTransport);

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

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

  //
  // Simple AT-TA target
  // - Request is accepted after fixed delay (relative to end of prev request
  //   phase)
  // - Response is started after fixed 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]);
      }

      // End request phase after accept delay
      t += ACCEPT_DELAY;
      phase = tlm::END_REQ;

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

      // AT-noTA target
      // - always return false
      // - immediately return delay to indicate end of phase
      return tlm::TLM_UPDATED;

    } 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 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]);
    }

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

    } else {
      // initiator will call nb_transport to indicate end of response phase
    }
  }

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

    // Start processing next transaction when previous response is accepted.
    // Notify begin of response phase after RESPONSE delay
    if (!mResponseQueue.empty()) {
      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*> mResponseQueue;
  sc_core::sc_event mBeginResponseEvent;
  sc_core::sc_event mEndResponseEvent;
};

#endif