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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()