Subversion Repositories openrisc

// ----------------------------------------------------------------------------
 
// 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()