Subversion Repositories openrisc_2011-10-31

// ----------------------------------------------------------------------------
 
// The TAP state machine: 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.
 
// The C/C++ parts of this program are commented throughout in a fashion
// suitable for processing with Doxygen.
 
// ----------------------------------------------------------------------------
 
// $Id$
 
#include "TapStateMachine.h"
 
//! Constructor
 
//! Start in the Test-Logic-Reset state, although we cannot know this reflects
//! the hardware until it has been through a TAP reset sequence. This is
//! reflected in the ::tapResetDone flag.
 
TapStateMachine::TapStateMachine () :
  state (TAP_TEST_LOGIC_RESET),
  resetDone (false)
{
 
}	// TapStateMachine ()
 
 
//! Accessor to get the current TAP state
 
//! Only guaranteed to match the target hardware if it has been through a
//! reset sequence.
 
//! @return  The current TAP state
TapState
TapStateMachine::getState ()
{
  return  state;
 
}	// getState ()
 
 
//! Accessor to get the current TAP reset state.
 
//! It is the responsibility of classes using this class to correctly set this
//! state.
 
//! @return  The current TAP reset state
bool
TapStateMachine::getResetDone ()
{
  return  resetDone;
 
}	// getResetDone ()
 
 
//! Accessor to set the current TAP reset state.
 
//! It is the responsibility of classes using this class to correctly set this
//! state.
 
//! @param[in]  The desired TAP reset state
void
TapStateMachine::setResetDone (bool _resetDone)
{
  resetDone = _resetDone;
 
}	// setResetDone ()
 
 
//! Drive the TAP state machine
 
//! @param tms       The JTAG TMS pin
void
TapStateMachine::nextState (bool  tms)
{
  static const TapState mapHigh[TAP_SIZE] = {	// When TMS = 1/true	      
    TAP_TEST_LOGIC_RESET,		// from TAP_TEST_LOGIC_RESET  
    TAP_SELECT_DR_SCAN,			// from TAP_RUN_TEST_IDLE     
    TAP_SELECT_IR_SCAN,			// from TAP_SELECT_DR_SCAN    
    TAP_EXIT1_DR,			// from TAP_CAPTURE_DR	      
    TAP_EXIT1_DR,			// from TAP_SHIFT_DR	      
    TAP_UPDATE_DR,			// from TAP_EXIT1_DR	      
    TAP_EXIT2_DR,			// from TAP_PAUSE_DR	      
    TAP_UPDATE_DR,			// from TAP_EXIT2_DR	      
    TAP_SELECT_DR_SCAN,			// from TAP_UPDATE_DR	      
    TAP_TEST_LOGIC_RESET,		// from TAP_SELECT_IR_SCAN    
    TAP_EXIT1_IR,			// from TAP_CAPTURE_IR	      
    TAP_EXIT1_IR,			// from TAP_SHIFT_IR	      
    TAP_UPDATE_IR,			// from TAP_EXIT1_IR	      
    TAP_EXIT2_IR,			// from TAP_PAUSE_IR	      
    TAP_UPDATE_IR,			// from TAP_EXIT2_IR	      
    TAP_SELECT_DR_SCAN};		// from TAP_UPDATE_IR	      
 
  static const TapState mapLow[TAP_SIZE] = {	// When TMS = 0/false
    TAP_RUN_TEST_IDLE,			// from TAP_TEST_LOGIC_RESET
    TAP_RUN_TEST_IDLE,			// from TAP_RUN_TEST_IDLE   
    TAP_CAPTURE_DR,			// from TAP_SELECT_DR_SCAN  
    TAP_SHIFT_DR,			// from TAP_CAPTURE_DR	    
    TAP_SHIFT_DR,			// from TAP_SHIFT_DR	    
    TAP_PAUSE_DR,			// from TAP_EXIT1_DR	    
    TAP_PAUSE_DR,			// from TAP_PAUSE_DR	    
    TAP_SHIFT_DR,			// from TAP_EXIT2_DR	    
    TAP_RUN_TEST_IDLE,			// from TAP_UPDATE_DR	    
    TAP_CAPTURE_IR,			// from TAP_SELECT_IR_SCAN  
    TAP_SHIFT_IR,			// from TAP_CAPTURE_IR	    
    TAP_SHIFT_IR,			// from TAP_SHIFT_IR	    
    TAP_PAUSE_IR,			// from TAP_EXIT1_IR	    
    TAP_PAUSE_IR,			// from TAP_PAUSE_IR	    
    TAP_SHIFT_IR,			// from TAP_EXIT2_IR	    
    TAP_RUN_TEST_IDLE };		// from TAP_UPDATE_IR	      
 
  state = tms ? mapHigh[state] : mapLow[state];
 
}	// nextState()
 
 
//! Determine if we are in a particular TAP state
 
//! Set TMS to get there optimally
 
//! @param[in]  target  The desired TAP state
//! @param[out] tms     Value of TMS to move towards the target state. Set
//!                     even if we are already in the state (in case we want
//!                     to loop).
 
//! @return  True if we are already in the target state
bool
TapStateMachine::targetState (TapState  target,
			      bool     &tms)
{
  // Map of the value of TMS which moves the state machine from the the state
  // in the row (first) to the state in the column (second)
  static const bool map[TAP_SIZE][TAP_SIZE] = {
  //  T  R  S  C  S  E  P  E  U  S  C  S  E  P  E  U 
  //  L  T  D  D  D  1  D  2  D  I  I  I  1  I  2  I
  //  R  I  R  R  R  D  R  D  R  R  R  R  I  R  I  R
  //        S        R     R     S        R     R
    { 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },  // map[TLR][x]
    { 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 },  // map[RTI][x]
    { 1, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1 },  // map[SDRS][x]
    { 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 },  // map[CDR][x]
    { 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 },  // map[SDR][x]
    { 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1 },  // map[E1DR][x]
    { 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1 },  // map[PDR][x]
    { 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1 },  // map[E2DR][x]
    { 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 },  // map[UDR][x]
    { 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0 },  // map[SIRS][x]
    { 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1 },  // map[CIR][x]
    { 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1 },  // map[SIR][x]
    { 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 1 },  // map[E1IR][x]
    { 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1 },  // map[PIR][x]
    { 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 1 },  // map[E2IR][x]
    { 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 }}; // map[UIR][x]
 
  tms = map[state][target];
  return state == target;
 
}	// targetState()