mg5uart.c

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

 *  wrappers which are nearly functionally identical.
 */


#define __ISR(_TYPE, _OFFSET) \
  MG5UART_STATIC void mg5uart_process_isr_ ## _TYPE ( \
    int  minor \
  ); \
  \
  MG5UART_STATIC rtems_isr mg5uart_isr_ ## _TYPE ( \
    rtems_vector_number vector \
  ) \
  { \
    int   minor; \
    extern void mips_default_isr(int vector); \
   \
    for(minor=0 ; minor<Console_Port_Count ; minor++) { \
      if( Console_Port_Tbl[minor].deviceType == SERIAL_MG5UART && \
          vector == Console_Port_Tbl[minor].ulIntVector + _OFFSET ) { \
        mg5uart_process_isr_ ## _TYPE (minor); \
	return; \
      } \
    } \
    mips_default_isr( vector ); \
  }

__ISR(rx_frame_error, MG5UART_IRQ_RX_FRAME_ERROR)
__ISR(rx_overrun_error, MG5UART_IRQ_RX_OVERRUN_ERROR)
__ISR(tx_empty, MG5UART_IRQ_TX_EMPTY)
__ISR(tx_ready, MG5UART_IRQ_TX_READY)
__ISR(rx_ready, MG5UART_IRQ_RX_READY)





MG5UART_STATIC void mg5uart_process_isr_rx_error(
   int  minor, 
   unsigned32 mask 
)
{
  unsigned32              pMG5UART;
  int                     shift;

  pMG5UART      = Console_Port_Tbl[minor].ulCtrlPort1;

  if ( Console_Port_Tbl[minor].ulDataPort == MG5UART_UART0 )
    shift = MONGOOSEV_UART0_IRQ_SHIFT;
  else
    shift = MONGOOSEV_UART1_IRQ_SHIFT;

  /* now clear the error */

  MG5UART_SETREG(
     pMG5UART,
     MG5UART_STATUS_REGISTER,
     mask << shift );
}


MG5UART_STATIC void mg5uart_process_isr_rx_frame_error(
  int  minor
)
{
   mg5uart_process_isr_rx_error( minor, MONGOOSEV_UART_RX_FRAME_ERROR );
}

MG5UART_STATIC void mg5uart_process_isr_rx_overrun_error(
  int  minor
)
{
   mg5uart_process_isr_rx_error( minor, MONGOOSEV_UART_RX_OVERRUN_ERROR );
}








MG5UART_STATIC void mg5uart_process_tx_isr(
   int        minor,
   unsigned32 source
)
{
   unsigned32      pMG5UART;
   int             shift;
   
   pMG5UART      = Console_Port_Tbl[minor].ulCtrlPort1;

   mg5uart_enable_interrupts(minor, MG5UART_ENABLE_ALL_EXCEPT_TX);

   if ( Console_Port_Tbl[minor].ulDataPort == MG5UART_UART0 )
      shift = MONGOOSEV_UART0_IRQ_SHIFT;
   else
      shift = MONGOOSEV_UART1_IRQ_SHIFT;
      
   MG5UART_SETREG(
      pMG5UART,
      MG5UART_STATUS_REGISTER,
      source << shift );

   if( rtems_termios_dequeue_characters( Console_Port_Data[minor].termios_data, 1) )
   {
      mg5uart_enable_interrupts(minor, MG5UART_ENABLE_ALL);
      return;
   }

   /*
    *  There are no more characters to transmit.  The tx interrupts are be cleared
    *  by writing data to the uart, so just disable the tx interrupt sources.
    */
  
   Console_Port_Data[minor].bActive = FALSE;

   /* mg5uart_enable_interrupts(minor, MG5UART_ENABLE_ALL_EXCEPT_TX); */
}



MG5UART_STATIC void mg5uart_process_isr_tx_empty(
  int  minor
)
{
   /* mg5uart_process_tx_isr( minor, MONGOOSEV_UART_TX_EMPTY ); */
}

MG5UART_STATIC void mg5uart_process_isr_tx_ready(
  int  minor
)
{
   mg5uart_process_tx_isr( minor, MONGOOSEV_UART_TX_READY );
}





MG5UART_STATIC void mg5uart_process_isr_rx_ready(
  int  minor
)
{
  unsigned32              pMG5UART_port;
  unsigned char           c;

  pMG5UART_port = Console_Port_Tbl[minor].ulCtrlPort2;

  /* reading the RX buffer automatically resets the interrupt flag */

  c = (unsigned char) MG5UART_GETREG(pMG5UART_port, MG5UART_RX_BUFFER);

  rtems_termios_enqueue_raw_characters(
     Console_Port_Data[minor].termios_data,
     &c, 1 );
}






/*
 *  mg5uart_initialize_interrupts
 *
 *  This routine initializes the console's receive and transmit
 *  ring buffers and loads the appropriate vectors to handle the interrupts.
 */

MG5UART_STATIC void mg5uart_initialize_interrupts(int minor)
{
  unsigned long v;
  mg5uart_init(minor);

  Console_Port_Data[minor].bActive = FALSE;
  v = Console_Port_Tbl[minor].ulIntVector;

  set_vector(mg5uart_isr_rx_frame_error,   v + MG5UART_IRQ_RX_FRAME_ERROR, 1);
  set_vector(mg5uart_isr_rx_overrun_error, v + MG5UART_IRQ_RX_OVERRUN_ERROR, 1);
  set_vector(mg5uart_isr_tx_empty,         v + MG5UART_IRQ_TX_EMPTY, 1);
  set_vector(mg5uart_isr_tx_ready,         v + MG5UART_IRQ_TX_READY, 1);
  set_vector(mg5uart_isr_rx_ready,         v + MG5UART_IRQ_RX_READY, 1);

  mg5uart_enable_interrupts(minor, MG5UART_ENABLE_ALL_EXCEPT_TX);
}





/*
 *  mg5uart_write_support_int
 *
 *  Console Termios output entry point when using interrupt driven output.
 */

MG5UART_STATIC int mg5uart_write_support_int(
  int         minor,
  const char *buf,
  int         len
)
{
  unsigned32      Irql;
  unsigned32      pMG5UART_port;

  pMG5UART_port = Console_Port_Tbl[minor].ulCtrlPort2;

  /*
   *  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);

  MG5UART_SETREG(pMG5UART_port, MG5UART_TX_BUFFER, *buf);

  if( Console_Port_Data[minor].bActive == FALSE ) 
  {
     Console_Port_Data[minor].bActive = TRUE;
     mg5uart_enable_interrupts(minor, MG5UART_ENABLE_ALL);
  }

  rtems_interrupt_enable(Irql);
  return 1;
}




/*
 *  mg5uart_write_support_polled
 *
 *  Console Termios output entry point when using polled output.
 *
 */

MG5UART_STATIC int mg5uart_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) 
  {
    mg5uart_write_polled(minor, *buf++);
    nwrite++;
  }

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

/*
 *  mg5uart_inbyte_nonblocking_polled
 *
 *  Console Termios polling input entry point.
 */

MG5UART_STATIC int mg5uart_inbyte_nonblocking_polled(
  int minor
)
{
  unsigned32              pMG5UART;
  unsigned32              pMG5UART_port;
  unsigned32              status;
  unsigned32              tmp,shift;

  pMG5UART      = Console_Port_Tbl[minor].ulCtrlPort1;
  pMG5UART_port = Console_Port_Tbl[minor].ulCtrlPort2;

  if ( Console_Port_Tbl[minor].ulDataPort == MG5UART_UART0 )
    shift = MONGOOSEV_UART0_IRQ_SHIFT;
  else
    shift = MONGOOSEV_UART1_IRQ_SHIFT;

  /* reset overrrun or framing errors */
  status = MG5UART_GETREG(pMG5UART, MG5UART_STATUS_REGISTER) >> shift;

  if( (tmp = (status & 0x3)) )
  {
     MG5UART_SETREG(pMG5UART, MG5UART_STATUS_REGISTER, (tmp << shift) );
     status = MG5UART_GETREG(pMG5UART, MG5UART_STATUS_REGISTER) >> shift;
  }

  if ( status & MONGOOSEV_UART_RX_READY ) 
  {
     return (int) MG5UART_GETREG(pMG5UART_port, MG5UART_RX_BUFFER);
  } 
  else 
  {
     return -1;
  }
}

/*
 *  mg5uart_baud_rate
 */

MG5UART_STATIC int mg5uart_baud_rate(
  int           minor,
  int           baud,
  unsigned int *code
)
{
  rtems_unsigned32 clock;
  rtems_unsigned32 tmp_code;
  rtems_unsigned32 baud_requested;

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

  baud_requested = termios_baud_to_number( baud_requested );

  clock = (rtems_unsigned32) Console_Port_Tbl[minor].ulClock;
  if (!clock)
    rtems_fatal_error_occurred(RTEMS_INVALID_NUMBER);

  /*
   *  Formula is Code = round(ClockFrequency / Baud - 1).
   *
   *  Since this is integer math, we will divide by twice the baud and
   *  check the remaining odd bit.
   */

  tmp_code = (clock / baud_requested) - 1;

  /*
   *  From section 12.7, "Keep C>100 for best receiver operation."
   *  That is 100 cycles which is not a lot of instructions.  It is
   *  reasonable to think that the Mongoose-V could not keep
   *  up with C < 100.
   */

  if ( tmp_code < 100 )
    return RTEMS_INVALID_NUMBER;

  /*
   *  upper word is receiver baud and lower word is transmitter baud
   */

  *code = (tmp_code << 16) | tmp_code;

  return 0;
}




/*
 *  mg5uart_enable_interrupts
 *
 *  This function enables specific interrupt sources on the DUART.
 */

MG5UART_STATIC void mg5uart_enable_interrupts(
  int minor,
  int mask
)
{
  unsigned32            pMG5UART;
  unsigned32		maskSave;
  unsigned32            shift;
  rtems_interrupt_level  Irql;

  pMG5UART = Console_Port_Tbl[minor].ulCtrlPort1;

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

  if ( Console_Port_Tbl[minor].ulDataPort == MG5UART_UART0 )
    shift = MONGOOSEV_UART0_IRQ_SHIFT;
  else
    shift = MONGOOSEV_UART1_IRQ_SHIFT;


  rtems_interrupt_disable(Irql);

  maskSave = MG5UART_GETREG( pMG5UART, MG5UART_INTERRUPT_MASK_REGISTER );

  MG5UART_SETREG(
     pMG5UART,
     MG5UART_INTERRUPT_MASK_REGISTER,
     (maskSave & ~(MONGOOSEV_UART_ALL_STATUS_BITS << shift)) | (mask << shift) );

  rtems_interrupt_enable(Irql);
}



/*
 * Flow control is only supported when using interrupts
 */

console_fns mg5uart_fns =
{
  libchip_serial_default_probe,   /* deviceProbe */
  mg5uart_open,                   /* deviceFirstOpen */
  NULL,                           /* deviceLastClose */
  NULL,                           /* deviceRead */
  mg5uart_write_support_int,      /* deviceWrite */
  mg5uart_initialize_interrupts,  /* deviceInitialize */
  mg5uart_write_polled,           /* deviceWritePolled */
  mg5uart_set_attributes,         /* deviceSetAttributes */
  TRUE                            /* deviceOutputUsesInterrupts */
};

console_fns mg5uart_fns_polled =
{
  libchip_serial_default_probe,        /* deviceProbe */
  mg5uart_open,                        /* deviceFirstOpen */
  mg5uart_close,                       /* deviceLastClose */
  mg5uart_inbyte_nonblocking_polled,   /* deviceRead */
  mg5uart_write_support_polled,        /* deviceWrite */
  mg5uart_init,                        /* deviceInitialize */
  mg5uart_write_polled,                /* deviceWritePolled */
  mg5uart_set_attributes,              /* deviceSetAttributes */
  FALSE,                               /* deviceOutputUsesInterrupts */
};