Subversion Repositories openrisc_2011-10-31

// ----------------------------------------------------------------------------
 
// TAP action header: abstract class 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 <iostream>
 
#include "TapAction.h"
 
class  sc_event;
 
 
//! Constructor
 
//! Records the SystemC event used to notify completion and sets the
//! resetCounter to zero.
 
//! @param _actionType  The action type
 
TapAction::TapAction (sc_core::sc_event *_doneEvent) :
  doneEvent (_doneEvent),
  resetCounter (0)
{
 
}	// TapAction ()
 
 
//! Accessor to get the SystemC completion event
 
//! @return  The SystemC completion event
 
sc_core::sc_event *
TapAction::getDoneEvent ()
{
  return  doneEvent;
 
}	// getDoneEvent ()
 
 
//! Function to check the TAP is in a consistent state, optionally with a
//! warning.
 
//! This is a convenience for subclasses (hence protected), so they can ensure
//! the state machine is in a consistent state.
 
//! @note The method returns TRUE to indicate that the machine is in the
//!       consistent state. However the TapStateMachine resetDone flag is set
//!       when the final TMS is set - the state will only be reached IF that
//!       TMS is driven. This mechanism gives users flexibility. They can
//!       detect the final TMS being driven.
 
//! @param[in]  tapStateMachine  The TAP state machine with which we are
//!                              associated.
//! @param[out] tms              The value to drive on the JTAG TMS
//! @param[in]  warn             True to indicate a warning message should be
//!                              issued when starting a reset cycle.
 
//! @return  TRUE if the TAP state machine was already in a consistent state.
 
bool
TapAction::checkResetDone (TapStateMachine *tapStateMachine,
			   bool            &tms,
			   bool             warn)
{
  // Nothing more to do if we are consistent
  if (tapStateMachine->getResetDone ())
    {
      return  true;
    }
 
  // Need to reset. If requested and this is the first cycle of reset, give a
  // warning.
  if (warn && (0 == resetCounter))
    {
      std::cerr << "JTAG TAP state inconsistent: resetting" << std::endl;
    }
 
  // Drive towards reset
  resetCounter++;
  tms = 1;
 
  // If we have got to the end of the reset sequence we can clear the
  // tapStateMachine and report we are consistent. However we will not return
  // true until the next call.
  if (tapStateMachine->TAP_RESET_CYCLES == resetCounter)
    {
      tapStateMachine->setResetDone (true);
      resetCounter = 0;				// Ready for next time
    }
  else
    {
      return false;
    }
}	// checkResetDone ()