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()