mc68681.c

RTEMS (Real-Time Executive for Multiprocessor Systems) is a free open source real-time operating sys

#endif
     ucLineStatus = (*getReg)(pMC68681_port, MC68681_STATUS);
     if(!--iTimeout) {
       break;
     }
  }

  /*
   * transmit character
   */

  (*setReg)(pMC68681_port, MC68681_TX_BUFFER, cChar);
}

/*
 *  mc68681_isr
 *
 *  This is the single interrupt entry point which parcels interrupts
 *  out to the various ports.
 */

MC68681_STATIC rtems_isr mc68681_isr(
  rtems_vector_number vector
)
{
  int     minor;

  for(minor=0 ; minor<Console_Port_Count ; minor++) {
    if(Console_Port_Tbl[minor].ulIntVector == vector && 
       Console_Port_Tbl[minor].deviceType == SERIAL_MC68681 ) {
      mc68681_process(minor);
    }
  }
}

/*
 *  mc68681_initialize_interrupts
 *
 *  This routine initializes the console's receive and transmit
 *  ring buffers and loads the appropriate vectors to handle the interrupts.
 */

MC68681_STATIC void mc68681_initialize_interrupts(int minor)
{
  mc68681_init(minor);

  Console_Port_Data[minor].bActive = FALSE;

  set_vector(mc68681_isr, Console_Port_Tbl[minor].ulIntVector, 1);

  mc68681_enable_interrupts(minor,MC68681_IMR_ENABLE_ALL_EXCEPT_TX);
}

/* 
 *  mc68681_write_support_int
 *
 *  Console Termios output entry point when using interrupt driven output.
 */

MC68681_STATIC int mc68681_write_support_int(
  int         minor, 
  const char *buf, 
  int         len
)
{
  unsigned32      Irql;
  unsigned32      pMC68681_port;
  setRegister_f   setReg;

  pMC68681_port = Console_Port_Tbl[minor].ulCtrlPort2;
  setReg        = Console_Port_Tbl[minor].setRegister;

  /*
   *  We are using interrupt driven output and termios only sends us
   *  one character at a time.
   */

  if ( !len )
    return 0;

  /*
   *  Put the character out and enable interrupts if necessary.
   */

  rtems_interrupt_disable(Irql);
    if ( Console_Port_Data[minor].bActive == FALSE ) {
      Console_Port_Data[minor].bActive = TRUE;
      mc68681_enable_interrupts(minor, MC68681_IMR_ENABLE_ALL);
    }
    (*setReg)(pMC68681_port, MC68681_TX_BUFFER, *buf);
  rtems_interrupt_enable(Irql);

  return 1;
}

/* 
 *  mc68681_write_support_polled
 *
 *  Console Termios output entry point when using polled output.
 *
 */

MC68681_STATIC int mc68681_write_support_polled(
  int         minor, 
  const char *buf, 
  int         len
)
{
  int nwrite = 0;

  /*
   * poll each byte in the string out of the port.
   */
  while (nwrite < len) {
    /*
     * transmit character
     */
    mc68681_write_polled(minor, *buf++);
    nwrite++;
  }

  /*
   * return the number of bytes written.
   */
  return nwrite;
}

/* 
 *  mc68681_inbyte_nonblocking_polled 
 *
 *  Console Termios polling input entry point.
 */

MC68681_STATIC int mc68681_inbyte_nonblocking_polled( 
  int minor 
)
{
  unsigned32           pMC68681_port;
  unsigned char        ucLineStatus;
  unsigned char        cChar;
  getRegister_f        getReg;

  pMC68681_port = Console_Port_Tbl[minor].ulCtrlPort2;
  getReg        = Console_Port_Tbl[minor].getRegister;

  ucLineStatus = (*getReg)(pMC68681_port, MC68681_STATUS);
  if(ucLineStatus & MC68681_RX_READY) {
    cChar = (*getReg)(pMC68681_port, MC68681_RX_BUFFER);
    return (int)cChar;
  } else {
    return -1;
  }
}

/*
 *  mc68681_baud_rate
 */

MC68681_STATIC int mc68681_baud_rate(
  int           minor,
  int           baud,
  unsigned int *baud_mask_p,
  unsigned int *acr_bit_p,
  unsigned int *command
)
{
  unsigned int           baud_mask;
  unsigned int           acr_bit;
  int                    status;
  int                    is_extended;
  int                    baud_requested;
  mc68681_baud_table_t  *baud_tbl;

  baud_mask = 0;
  acr_bit = 0;
  status = 0;

  if (Console_Port_Tbl[minor].ulDataPort & MC68681_DATA_BAUD_RATE_SET_2)
  {
    acr_bit = 1;
  }

  is_extended = 0;

  switch (Console_Port_Tbl[minor].ulDataPort & MC68681_XBRG_MASK) {
    case MC68681_XBRG_IGNORED:
      *command = 0x00;
      break;
    case MC68681_XBRG_ENABLED:
      *command = 0x80;
      is_extended = 1;
      break;
    case MC68681_XBRG_DISABLED:
      *command = 0x90;
      break;
  }

  baud_requested = baud & CBAUD;
  if (!baud_requested)
    baud_requested = B9600;              /* default to 9600 baud */
  
  baud_requested = termios_baud_to_index( baud_requested );

  baud_tbl = (mc68681_baud_table_t *) Console_Port_Tbl[minor].ulClock;
  if (!baud_tbl)
    rtems_fatal_error_occurred(RTEMS_INVALID_ADDRESS);

  if ( is_extended )
    baud_mask = (unsigned int)baud_tbl[ acr_bit + 2 ][ baud_requested ];
  else
    baud_mask = baud_tbl[ acr_bit ][ baud_requested ];

  if ( baud_mask == MC68681_BAUD_NOT_VALID )
    status = -1;

  /*
   *  upper nibble is receiver and lower nibble is transmitter
   */

  *baud_mask_p = (baud_mask << 4) | baud_mask;
  *acr_bit_p   = acr_bit;
  return status;
}

/*
 *  mc68681_process
 *
 *  This routine is the per port console interrupt handler.
 */

MC68681_STATIC void mc68681_process(
  int  minor
)
{
  unsigned32              pMC68681;
  unsigned32              pMC68681_port;
  volatile unsigned8      ucLineStatus; 
  volatile unsigned8      ucISRStatus; 
  unsigned char           cChar;
  getRegister_f           getReg;
  setRegister_f           setReg;

  pMC68681      = Console_Port_Tbl[minor].ulCtrlPort1;
  pMC68681_port = Console_Port_Tbl[minor].ulCtrlPort2;
  getReg        = Console_Port_Tbl[minor].getRegister;
  setReg        = Console_Port_Tbl[minor].setRegister;

  /* Get ISR at the beginning of the IT routine */ 
  ucISRStatus = (*getReg)(pMC68681, MC68681_INTERRUPT_STATUS_REG);
  
  /* Get good ISR a or b channel */
  if (pMC68681 != pMC68681_port){
    ucISRStatus >>= 4;
  }
    
  /* See if is usefull to call rtems_termios_dequeue */
  if(Console_Port_Data[minor].bActive == FALSE) {
		ucISRStatus = ucISRStatus & ~MC68681_IR_TX_READY;
  }

  /*
   * Deal with any received characters
   */
  while(TRUE) {
    ucLineStatus = (*getReg)(pMC68681_port, MC68681_STATUS);
    if(!(ucLineStatus & MC68681_RX_READY)) {
      break;
    }
    /*
     *  If there is a RX error, then dump all the data.
     */
    if ( ucLineStatus & MC68681_RX_ERRORS ) {
      do {
        cChar = (*getReg)(pMC68681_port, MC68681_RX_BUFFER);
        ucLineStatus = (*getReg)(pMC68681_port, MC68681_STATUS);
      } while ( ucLineStatus & MC68681_RX_READY );
      continue;
    }
    cChar = (*getReg)(pMC68681_port, MC68681_RX_BUFFER);
    rtems_termios_enqueue_raw_characters( 
      Console_Port_Data[minor].termios_data,
      &cChar, 
      1 
    );
  }

  /*
   *  Deal with the transmitter
   */

  if (ucISRStatus & MC68681_IR_TX_READY) {
    if (!rtems_termios_dequeue_characters(
          Console_Port_Data[minor].termios_data, 1)) {
	  /* If no more char to send, disable TX interrupt */
      Console_Port_Data[minor].bActive = FALSE;
      mc68681_enable_interrupts(minor, MC68681_IMR_ENABLE_ALL_EXCEPT_TX);
    }
  }
}

/*
 *  mc68681_build_imr
 *
 *  This function returns the value for the interrupt mask register for this
 *  DUART.  Since this is a shared register, we must look at the other port
 *  on this chip to determine whether or not it is using interrupts.
 */

MC68681_STATIC unsigned int mc68681_build_imr(
  int  minor,
  int  enable_flag
)
{
  int              mate;
  int              is_a;
  unsigned int     mask;
  unsigned int     mate_mask;
  unsigned int     pMC68681;
  unsigned int     pMC68681_port;
  mc68681_context *pmc68681Context;
  mc68681_context *mateContext;
  
  pMC68681        = Console_Port_Tbl[minor].ulCtrlPort1;
  pMC68681_port   = Console_Port_Tbl[minor].ulCtrlPort2;
  pmc68681Context = (mc68681_context *) Console_Port_Data[minor].pDeviceContext;
  mate            = pmc68681Context->mate;

  mask = 0;
  mate_mask = 0;

  is_a = (pMC68681 == pMC68681_port);
 
  /*
   *  If there is a mate for this port, get its IMR mask.
   */

  if ( mate != -1 ) {
    mateContext = Console_Port_Data[mate].pDeviceContext;
    
    if (mateContext)
      mate_mask = mateContext->imr;
  }

  /*
   *  Calculate this port's IMR mask and save it in the context area.
   */

  if ( Console_Port_Tbl[minor].pDeviceFns->deviceOutputUsesInterrupts )
    mask = enable_flag;

  pmc68681Context->imr = mask;

  /*
   *  Now return the full IMR value
   */

  if (is_a)
    return (mate_mask << 4) | mask;

  return (mask << 4) | mate_mask;
}

/*
 *  mc68681_enable_interrupts
 *
 *  This function enables specific interrupt sources on the DUART.
 */

MC68681_STATIC void mc68681_enable_interrupts(
  int minor,
  int imr_mask
)
{
  unsigned32            pMC68681;
  setRegister_f         setReg;

  pMC68681 = Console_Port_Tbl[minor].ulCtrlPort1;
  setReg   = Console_Port_Tbl[minor].setRegister;

  /*
   *  Enable interrupts on RX and TX -- not break
   */

  (*setReg)(
     pMC68681,
     MC68681_INTERRUPT_MASK_REG,
     mc68681_build_imr(minor, imr_mask)
  );
}