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// ----------------------------------------------------------------------------

// Main module providing the JTAG interface: implementation

// Copyright (C) 2009  Embecosm Limited <info@embecosm.com>

// Contributor Jeremy Bennett <jeremy.bennett@embecosm.com>

// This file is part of the Embecosm cycle accurate SystemC JTAG library.

// This program is free software: you can redistribute it and/or modify it

// under the terms of the GNU Lesser General Public License as published by

// the Free Software Foundation, either version 3 of the License, or (at your

// option) any later version.

// This program is distributed in the hope that it will be useful, but WITHOUT

// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public

// License for more details.

// You should have received a copy of the GNU Lesser General Public License

// along with this program.  If not, see <http://www.gnu.org/licenses/>.

// The C/C++ parts of this program are commented throughout in a fashion

// suitable for processing with Doxygen.

// ----------------------------------------------------------------------------

// $Id$

#include "JtagSC.h"

SC_HAS_PROCESS( JtagSC );

//! Constructor for the JTAG handler.

//! @param[in] name       Name of this module, passed to the parent

//!                       constructor. 

//! @param[in] fifo_size  Size of the FIFO on which to queue TAP actions.

JtagSC::JtagSC (sc_core::sc_module_name  name,

                int                      fifo_size) :

  sc_module (name),

  currentTapAction (NULL)

{

  tapActionQueue = new sc_core::sc_fifo<TapAction *> (fifo_size);

  stateMachine   = new TapStateMachine ();

  SC_METHOD (processActions);

  sensitive << tck.pos ();

}       // JtagSC ()

//! Destructor for the JTAG handler.

//! Give up our state machine and FIFO

JtagSC::~JtagSC ()

{

  delete  stateMachine;

  delete  tapActionQueue;

}       // ~JtagSC ()

//! Method to drive the jtag ports.

//! Initial version just drives the reset.

void

JtagSC::processActions()

{

  // TRST is driven as the inverse of the system reset

  trst = !sysReset;

  // Do nothing else if in CPU reset (active high)

  if (sysReset)

    {

      return;

    }

  // Functions setting the outputs will need bools (they are not generally

  // SystemC modules, so don't handle the likes of sc_in<> correctly).

  bool  tdi_o;

  bool  tms_o;

  // Try to get an action if we don't have one

  if (NULL == currentTapAction)

    {

      if (false == tapActionQueue->nb_read (currentTapAction))

        {

          // Nothing there, so head for Run-Test/Idle state.

          stateMachine->targetState (TAP_RUN_TEST_IDLE, tms_o);

          tms  = tms_o;

          return;

        }

    }

  // Process the action, notifying the originator when done.

  if (currentTapAction->process (stateMachine, tdi_o, tdo, tms_o))

    {

      currentTapAction->getDoneEvent()->notify();

      currentTapAction = NULL;

    }

  // Select the new TAP state

  stateMachine->nextState (tms_o);

  // Drive the signal ports

  tdi  = tdi_o;

  tms  = tms_o;

}       // processActions()