z8_serial.c

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 *   RX and TX interrupts are not enabled when by the attach method (unless the
 *   hardware supports multiple levels of interrupt enabling).  The RX and TX
 *   interrupts are not enabled until the txint() and rxint() methods are called.
 *
 ****************************************************************************/

static int z8_attach(FAR struct uart_dev_s *dev)
{
  struct z8_uart_s *priv = (struct z8_uart_s*)dev->priv;
  int ret;

  /* Attach the RX IRQ */

  ret = irq_attach(priv->rxirq, z8_rxinterrupt);
  if (ret == OK)
    {
      /* Attach the TX IRQ */

      ret = irq_attach(priv->txirq, z8_txinterrupt);
      if (ret != OK)
        {
          irq_detach(priv->rxirq);
        }
    }
  return ret;
}

/****************************************************************************
 * Name: z8_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 z8_detach(FAR struct uart_dev_s *dev)
{
  struct z8_uart_s *priv = (struct z8_uart_s*)dev->priv;
  up_disable_irq(priv->rxirq);
  up_disable_irq(priv->txirq);
  irq_detach(priv->rxirq);
  irq_detach(priv->txirq);
}

/****************************************************************************
 * Name: z8_rxinterrupt
 *
 * Description:
 *   This is the UART interrupt handler.  It will be invoked when an RX
 *   event occurs at the z8's LIN-UART.
 *
 ****************************************************************************/

static int z8_rxinterrupt(int irq, FAR void *context)
{
  struct uart_dev_s  *dev = NULL;
  struct z8_uart_s *priv;
  ubyte              status;

  if (g_uart1priv.rxirq == irq)
    {
      dev = &g_uart1port;
    }
  else if (g_uart0priv.rxirq == irq)
    {
      dev = &g_uart0port;
    }
  else
    {
      PANIC(OSERR_INTERNAL);
    }

  priv = (struct z8_uart_s*)dev->priv;

  /* Check the LIN-UART status 0 register to determine whether the source of
   * the interrupt is error, break, or received data
   */

  status = z8_getuart(priv, Z8_UART_STAT0);

  /* REVISIT error and break handling */

  /* Check if received data is available  */

  if (status & Z8_UARTSTAT0_RDA)
    {
      /* Handline an incoming, receive byte */

      uart_recvchars(dev);
    }
  return OK;
}

/****************************************************************************
 * Name: z8_txinterrupt
 *
 * Description:
 *   This is the UART TX interrupt handler.  This interrupt handler will
 *   be invoked when the X16F LIN UART transmit data register is empty.
 *
 ****************************************************************************/

static int z8_txinterrupt(int irq, FAR void *context)
{
  struct uart_dev_s  *dev = NULL;
  struct z8_uart_s *priv;
  ubyte              status;

  if (g_uart1priv.txirq == irq)
    {
      dev = &g_uart1port;
    }
  else if (g_uart0priv.txirq == irq)
    {
      dev = &g_uart0port;
    }
  else
    {
      PANIC(OSERR_INTERNAL);
    }

  priv = (struct z8_uart_s*)dev->priv;

  /* Verify that the transmit data register is empty */

  status = z8_getuart(priv, Z8_UART_STAT0);
  if (status & Z8_UARTSTAT0_TDRE)
    {
      /* Handle outgoing, transmit bytes */

      uart_xmitchars(dev);
    }
  return OK;
}

/****************************************************************************
 * Name: z8_ioctl
 *
 * Description:
 *   All ioctl calls will be routed through this method
 *
 ****************************************************************************/

static int z8_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
{
  *get_errno_ptr() = ENOTTY;
  return ERROR;
}

/****************************************************************************
 * Name: z8_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
 *   return 'status'.
 *
 ****************************************************************************/

static int z8_receive(FAR struct uart_dev_s *dev, FAR uint32 *status)
{
  struct z8_uart_s *priv = (struct z8_uart_s*)dev->priv;
  ubyte  rxd;
  ubyte  stat0;

  rxd     = z8_getuart(priv, Z8_UART_RXD);
  stat0   = z8_getuart(priv, Z8_UART_STAT0);
  *status = (uint32)rxd | (((uint32)stat0) << 8);
  return rxd;
}

/****************************************************************************
 * Name: z8_rxint
 *
 * Description:
 *   Call to enable or disable RX interrupts
 *
 ****************************************************************************/

static void z8_rxint(FAR struct uart_dev_s *dev, boolean enable)
{
  struct z8_uart_s *priv  = (struct z8_uart_s*)dev->priv;
  irqstate_t          flags = irqsave();

  if (enable)
    {
#ifndef CONFIG_SUPPRESS_SERIAL_INTS
      up_enable_irq(priv->rxirq);
#endif
    }
  else
    {
      up_disable_irq(priv->rxirq);
    }

  priv->rxenabled = enable;
  irqrestore(flags);
}

/****************************************************************************
 * Name: z8_rxavailable
 *
 * Description:
 *   Return TRUE if the receive fifo is not empty
 *
 ****************************************************************************/

static boolean z8_rxavailable(FAR struct uart_dev_s *dev)
{
  struct z8_uart_s *priv = (struct z8_uart_s*)dev->priv;
  return ((z8_getuart(priv, Z8_UART_STAT0) & Z8_UARTSTAT0_RDA) != 0);
}

/****************************************************************************
 * Name: z8_send
 *
 * Description:
 *   This method will send one byte on the UART
 *
 ****************************************************************************/

static void z8_send(FAR struct uart_dev_s *dev, int ch)
{
  struct z8_uart_s *priv = (struct z8_uart_s*)dev->priv;
  z8_putuart(priv, ch, Z8_UART_TXD);
}

/****************************************************************************
 * Name: z8_txint
 *
 * Description:
 *   Call to enable or disable TX interrupts
 *
 ****************************************************************************/

static void z8_txint(FAR struct uart_dev_s *dev, boolean enable)
{
  struct z8_uart_s *priv  = (struct z8_uart_s*)dev->priv;
  irqstate_t          flags = irqsave();

  if (enable)
    {
#ifndef CONFIG_SUPPRESS_SERIAL_INTS
      up_enable_irq(priv->txirq);
#endif
    }
  else
    {
      up_disable_irq(priv->txirq);
    }

  priv->txenabled = enable;
  irqrestore(flags);
}

/****************************************************************************
 * Name: z8_txready
 *
 * Description:
 *   Return TRUE if the tranmsit fifo is not full
 *
 ****************************************************************************/

static boolean z8_txready(FAR struct uart_dev_s *dev)
{
  struct z8_uart_s *priv = (struct z8_uart_s*)dev->priv;
  return ((z8_getuart(priv, Z8_UART_STAT0) & Z8_UARTSTAT0_TDRE) != 0);
}

/****************************************************************************
 * Name: z8_txempty
 *
 * Description:
 *   Return TRUE if the transmit fifo is empty
 *
 ****************************************************************************/

static boolean z8_txempty(FAR struct uart_dev_s *dev)
{
  struct z8_uart_s *priv = (struct z8_uart_s*)dev->priv;
  return ((z8_getuart(priv, Z8_UART_STAT0) & Z8_UARTSTAT0_TXE) != 0);
}

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

/****************************************************************************
 * Name: up_earlyserialinit
 *
 * 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 z8_serialinit.
 *
 ****************************************************************************/

void up_earlyserialinit(void)
{
  (void)z8_disableuartirq(&TTYS0_DEV);
  (void)z8_disableuartirq(&TTYS1_DEV);

  CONSOLE_DEV.isconsole = TRUE;
  z8_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)
{
  ubyte  state;

  /* Keep interrupts disabled so that we do not interfere with normal
   * driver operation 
   */

  state = z8_disableuartirq(&CONSOLE_DEV);

  /* Check for LF */

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

      z8_consoleput('\r');
    }

  /* Output the character */

  z8_consoleput((ubyte)ch);

  /* It is important to restore the TX interrupt while the send is pending.
   * otherwise, TRDE interrupts can be lost since they do not pend after the
   * TRDE false->true transition.
   */

  z8_restoreuartirq(&CONSOLE_DEV, state);
  return ch;
}

#else /* CONFIG_USE_SERIALDRIVER */

/****************************************************************************
 * Definitions
 ****************************************************************************/

#ifdef CONFIG_UART1_SERIAL_CONSOLE
# define z8_contrde() \
  ((getreg8(*(Z8_UART1_BASE+Z8_UART_STAT0)) & Z8_UARTSTAT0_TDRE) != 0)
# define z8_contxd(ch) \
  putreg8((ubyte)(ch), *(Z8_UART1_BASE+Z8_UART_TXD))
#else
# define z8_contrde() \
  ((getreg8(*(Z8_UART0_BASE+Z8_UART_STAT0)) & Z8_UARTSTAT0_TDRE) != 0)
# define z8_contxd(ch) \
  putreg8((ubyte)(ch), *(Z8_UART0_BASE+Z8_UART_TXD))
#endif

/****************************************************************************
 * Private Function Prototypes
 ****************************************************************************/

/****************************************************************************
 * Private Variables
 ****************************************************************************/

/****************************************************************************
 * Private Functions
 ****************************************************************************/

/****************************************************************************
 * Name: z8_putc
 ****************************************************************************/

static void z8_putc(int ch)
{
  int tmp;
  for (tmp = 1000 ; tmp > 0 && !z8_contrde(); tmp--);
  z8_contxd(ch);
}

/****************************************************************************
 * Public Functions
 ****************************************************************************/

/****************************************************************************
 * Name: up_putc
 ****************************************************************************/

int up_putc(int ch)
{
  /* Check for LF */

  if (ch == '\n')
    {
      /* Output CR before LF */

      z8_putc('\r');
    }

  /* Output character */

  z8_putc(ch);
  return ch;
}

#endif /* CONFIG_USE_SERIALDRIVER */