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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()