lpc214x_serial.c

這是一個實時嵌入式作業系統 實作了MCS51 ARM等MCU

  /* Attach and enable the IRQ */

  ret = irq_attach(priv->irq, up_interrupt);
  if (ret == OK)
    {
       /* Enable the interrupt (RX and TX interrupts are still disabled
        * in the UART
        */

       up_enable_irq(priv->irq);
    }
  return ret;
}

/****************************************************************************
 * Name: up_detach
 *
 * Description:
 *   Detach UART interrupts.  This method is called when the serial port is
 *   closed normally just before the shutdown method is called.  The exception is
 *   the serial console which is never shutdown.
 *
 ****************************************************************************/

static void up_detach(struct uart_dev_s *dev)
{
  struct up_dev_s *priv = (struct up_dev_s*)dev->priv;
  up_disable_irq(priv->irq);
  irq_detach(priv->irq);
}

/****************************************************************************
 * Name: up_interrupt
 *
 * Description:
 *   This is the UART interrupt handler.  It will be invoked
 *   when an interrupt received on the 'irq'  It should call
 *   uart_transmitchars or uart_receivechar to perform the
 *   appropriate data transfers.  The interrupt handling logic\
 *   must be able to map the 'irq' number into the approprite
 *   uart_dev_s structure in order to call these functions.
 *
 ****************************************************************************/

static int up_interrupt(int irq, void *context)
{
  struct uart_dev_s *dev = NULL;
  struct up_dev_s   *priv;
  ubyte              status;
  int                passes;

  if (g_uart1priv.irq == irq)
    {
      dev = &g_uart1port;
    }
  else if (g_uart0priv.irq == irq)
    {
      dev = &g_uart0port;
    }
  else
    {
      PANIC(OSERR_INTERNAL);
    }
  priv = (struct up_dev_s*)dev->priv;

  /* Loop until there are no characters to be transferred or,
   * until we have been looping for a long time.
   */

  for( passes = 0; passes < 256; passes++)
    {
      /* Get the current UART status and check for loop
       * termination conditions
       */

       status  = up_serialin(priv, LPC214X_UART_IIR_OFFSET);
      
      /* The NO INTERRUPT should be zero */
      
      if (status  !=  LPC214X_IIR_NO_INT)
        {
          /* Handline incoming, receive bytes (with or without timeout) */

          if (status == LPC214X_IIR_RDA_INT || status == LPC214X_IIR_CTI_INT)
            {
              uart_recvchars(dev);
            }

          /* Handle outgoing, transmit bytes */

          else if (status == LPC214X_IIR_THRE_INT)
            {
              uart_xmitchars(dev);
            }

          /* Just clear modem status interrupts */
        
          else if (status == LPC214X_IIR_MS_INT)
           {
             /* Read the modem status regisgter (MSR) to clear */
            
             (void)up_serialin(priv, LPC214X_UART_MSR_OFFSET);
           }

          /* Just clear any line status interrupts */
        
          else if (status == LPC214X_IIR_RLS_INT)
            {
              /* Read the line status register (LSR) to clear */
            
              (void)up_serialin(priv, LPC214X_UART_LSR_OFFSET);
            }
        }
    }
    return OK;
}

/****************************************************************************
 * Name: up_ioctl
 *
 * Description:
 *   All ioctl calls will be routed through this method
 *
 ****************************************************************************/

static int up_ioctl(struct file *filep, int cmd, unsigned long arg)
{
  struct inode      *inode = filep->f_inode;
  struct uart_dev_s *dev   = inode->i_private;
  struct up_dev_s   *priv  = (struct up_dev_s*)dev->priv;
  int                ret    = OK;

  switch (cmd)
    {
    case TIOCSERGSTRUCT:
      {
         struct up_dev_s *user = (struct up_dev_s*)arg;
         if (!user)
           {
             *get_errno_ptr() = EINVAL;
             ret = ERROR;
           }
         else
           {
             memcpy(user, dev, sizeof(struct up_dev_s));
           }
       }
       break;

    case TIOCSBRK:  /* BSD compatibility: Turn break on, unconditionally */
      {
        irqstate_t flags = irqsave();
        up_enablebreaks(priv, TRUE);
        irqrestore(flags);
      }
      break;

    case TIOCCBRK:  /* BSD compatibility: Turn break off, unconditionally */
      {
        irqstate_t flags;
        flags = irqsave();
        up_enablebreaks(priv, FALSE);
        irqrestore(flags);
      }
      break;

    default:
      *get_errno_ptr() = ENOTTY;
      ret = ERROR;
      break;
    }

  return ret;
}

/****************************************************************************
 * Name: up_receive
 *
 * Description:
 *   Called (usually) from the interrupt level to receive one
 *   character from the UART.  Error bits associated with the
 *   receipt are provided in the the return 'status'.
 *
 ****************************************************************************/

static int up_receive(struct uart_dev_s *dev, uint32 *status)
{
  struct up_dev_s *priv = (struct up_dev_s*)dev->priv;
  ubyte rbr;

  rbr     = up_serialin(priv, LPC214X_UART_RBR_OFFSET);
  *status = up_serialin(priv, LPC214X_UART_RBR_OFFSET);
  return rbr;
}

/****************************************************************************
 * Name: up_rxint
 *
 * Description:
 *   Call to enable or disable RX interrupts
 *
 ****************************************************************************/

static void up_rxint(struct uart_dev_s *dev, boolean enable)
{
  struct up_dev_s *priv = (struct up_dev_s*)dev->priv;
  if (enable)
    {
#ifndef CONFIG_SUPPRESS_SERIAL_INTS
      priv->ier |= LPC214X_IER_ERBFI;
#endif
    }
  else
    {
      priv->ier &= ~LPC214X_IER_ERBFI;
    }
  up_serialout(priv, LPC214X_UART_IER_OFFSET, priv->ier);
}

/****************************************************************************
 * Name: up_rxavailable
 *
 * Description:
 *   Return TRUE if the receive fifo is not empty
 *
 ****************************************************************************/

static boolean up_rxavailable(struct uart_dev_s *dev)
{
  struct up_dev_s *priv = (struct up_dev_s*)dev->priv;
  return ((up_serialin(priv, LPC214X_UART_LSR_OFFSET) & LPC214X_LSR_RDR) != 0);
}

/****************************************************************************
 * Name: up_send
 *
 * Description:
 *   This method will send one byte on the UART
 *
 ****************************************************************************/

static void up_send(struct uart_dev_s *dev, int ch)
{
  struct up_dev_s *priv = (struct up_dev_s*)dev->priv;
  up_serialout(priv, LPC214X_UART_THR_OFFSET, (ubyte)ch);
}

/****************************************************************************
 * Name: up_txint
 *
 * Description:
 *   Call to enable or disable TX interrupts
 *
 ****************************************************************************/

static void up_txint(struct uart_dev_s *dev, boolean enable)
{
  struct up_dev_s *priv = (struct up_dev_s*)dev->priv;
  if (enable)
    {
#ifndef CONFIG_SUPPRESS_SERIAL_INTS
      priv->ier |= LPC214X_IER_ETBEI;
#endif
    }
  else
    {
      priv->ier &= ~LPC214X_IER_ETBEI;
    }
  up_serialout(priv, LPC214X_UART_IER_OFFSET, priv->ier);
}

/****************************************************************************
 * Name: up_txready
 *
 * Description:
 *   Return TRUE if the tranmsit fifo is not full
 *
 ****************************************************************************/

static boolean up_txready(struct uart_dev_s *dev)
{
  struct up_dev_s *priv = (struct up_dev_s*)dev->priv;
  return ((up_serialin(priv, LPC214X_UART_LSR_OFFSET) & LPC214X_LSR_THRE) != 0);
}

/****************************************************************************
 * Name: up_txempty
 *
 * Description:
 *   Return TRUE if the transmit fifo is empty
 *
 ****************************************************************************/

static boolean up_txempty(struct uart_dev_s *dev)
{
  struct up_dev_s *priv = (struct up_dev_s*)dev->priv;
  return ((up_serialin(priv, LPC214X_UART_LSR_OFFSET) & LPC214X_LSR_THRE) != 0);
}

/****************************************************************************
 * Public Funtions
 ****************************************************************************/

/****************************************************************************
 * Name: up_serialinit
 *
 * Description:
 *   Performs the low level UART initialization early in 
 *   debug so that the serial console will be available
 *   during bootup.  This must be called before up_serialinit.
 *
 ****************************************************************************/

void up_earlyserialinit(void)
{
  /* Enable UART0 and 1 */
  
  uint32 pinsel = getreg32(LPC214X_PINSEL0);
  pinsel &= ~(LPC214X_UART0_PINMASK|LPC214X_UART1_PINMASK);
  pinsel |= (LPC214X_UART0_PINSEL|LPC214X_UART1_PINSEL);
  putreg32(pinsel, LPC214X_PINSEL0);

  /* Disable both UARTS */
  
  up_disableuartint(TTYS0_DEV.priv, NULL);
  up_disableuartint(TTYS1_DEV.priv, NULL);

  /* Configuration whichever on is the console */
  
  CONSOLE_DEV.isconsole = TRUE;
  up_setup(&CONSOLE_DEV);
}

/****************************************************************************
 * Name: up_serialinit
 *
 * Description:
 *   Register serial console and serial ports.  This assumes
 *   that up_earlyserialinit was called previously.
 *
 ****************************************************************************/

void up_serialinit(void)
{
  (void)uart_register("/dev/console", &CONSOLE_DEV);
  (void)uart_register("/dev/ttyS0", &TTYS0_DEV);
  (void)uart_register("/dev/ttyS1", &TTYS1_DEV);
}

/****************************************************************************
 * Name: up_putc
 *
 * Description:
 *   Provide priority, low-level access to support OS debug
 *   writes
 *
 ****************************************************************************/

int up_putc(int ch)
{
  struct up_dev_s *priv = (struct up_dev_s*)CONSOLE_DEV.priv;
  ubyte  ier;

  up_disableuartint(priv, &ier);
  up_waittxready(priv);
  up_serialout(priv, LPC214X_UART_THR_OFFSET, (ubyte)ch);

  /* Check for LF */

  if (ch == '\n')
    {
      /* Add CR */

      up_waittxready(priv);
      up_serialout(priv, LPC214X_UART_THR_OFFSET, '\r');
    }

  up_waittxready(priv);
  up_restoreuartint(priv, ier);
  return ch;
}