arch/arm/src/lpc214x/lpc214x_serial.c

/****************************************************************************
 * arch/arm/src/lpc214x/lpc214x_serial.c
 *
 * SPDX-License-Identifier: Apache-2.0
 *
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.  The
 * ASF licenses this file to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance with the
 * License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
 * License for the specific language governing permissions and limitations
 * under the License.
 *
 ****************************************************************************/

/****************************************************************************
 * Included Files
 ****************************************************************************/

#include <nuttx/config.h>

#include <sys/types.h>
#include <stdint.h>
#include <stdbool.h>
#include <unistd.h>
#include <string.h>
#include <assert.h>
#include <errno.h>
#include <debug.h>
#include <nuttx/irq.h>
#include <nuttx/arch.h>
#include <nuttx/fs/ioctl.h>
#include <nuttx/serial/serial.h>

#include "chip.h"
#include "arm_internal.h"
#include "lpc214x_pinsel.h"
#include "lpc214x_uart.h"

#ifdef USE_SERIALDRIVER

/****************************************************************************
 * Pre-processor Definitions
 ****************************************************************************/

/****************************************************************************
 * Private Types
 ****************************************************************************/

struct up_dev_s
{
  uint32_t uartbase;  /* Base address of UART registers */
  uint32_t baud;      /* Configured baud */
  uint8_t  ier;       /* Saved IER value */
  uint8_t  irq;       /* IRQ associated with this UART */
  uint8_t  parity;    /* 0=none, 1=odd, 2=even */
  uint8_t  bits;      /* Number of bits (7 or 8) */
  bool     stopbits2; /* true: Configure with 2 stop bits instead of 1 */
};

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

static int  up_setup(struct uart_dev_s *dev);
static void up_shutdown(struct uart_dev_s *dev);
static int  up_attach(struct uart_dev_s *dev);
static void up_detach(struct uart_dev_s *dev);
static int  up_interrupt(int irq, void *context, void *arg);
static int  up_ioctl(struct file *filep, int cmd, unsigned long arg);
static int  up_receive(struct uart_dev_s *dev, unsigned int *status);
static void up_rxint(struct uart_dev_s *dev, bool enable);
static bool up_rxavailable(struct uart_dev_s *dev);
static void up_send(struct uart_dev_s *dev, int ch);
static void up_txint(struct uart_dev_s *dev, bool enable);
static bool up_txready(struct uart_dev_s *dev);
static bool up_txempty(struct uart_dev_s *dev);

/****************************************************************************
 * Private Data
 ****************************************************************************/

static const struct uart_ops_s g_uart_ops =
{
  .setup          = up_setup,
  .shutdown       = up_shutdown,
  .attach         = up_attach,
  .detach         = up_detach,
  .ioctl          = up_ioctl,
  .receive        = up_receive,
  .rxint          = up_rxint,
  .rxavailable    = up_rxavailable,
#ifdef CONFIG_SERIAL_IFLOWCONTROL
  .rxflowcontrol  = NULL,
#endif
  .send           = up_send,
  .txint          = up_txint,
  .txready        = up_txready,
  .txempty    = up_txempty,
};

/* I/O buffers */

static char g_uart0rxbuffer[CONFIG_UART0_RXBUFSIZE];
static char g_uart0txbuffer[CONFIG_UART0_TXBUFSIZE];
static char g_uart1rxbuffer[CONFIG_UART1_RXBUFSIZE];
static char g_uart1txbuffer[CONFIG_UART1_TXBUFSIZE];

/* This describes the state of the LPC214X uart0 port. */

static struct up_dev_s g_uart0priv =
{
  .uartbase       = LPC214X_UART0_BASE,
  .baud           = CONFIG_UART0_BAUD,
  .irq            = LPC214X_UART0_IRQ,
  .parity         = CONFIG_UART0_PARITY,
  .bits           = CONFIG_UART0_BITS,
  .stopbits2      = CONFIG_UART0_2STOP,
};

static uart_dev_t g_uart0port =
{
  .recv     =
  {
    .size   = CONFIG_UART0_RXBUFSIZE,
    .buffer = g_uart0rxbuffer,
  },
  .xmit     =
  {
    .size   = CONFIG_UART0_TXBUFSIZE,
    .buffer = g_uart0txbuffer,
  },
  .ops      = &g_uart_ops,
  .priv     = &g_uart0priv,
};

/* This describes the state of the LPC214X uart1 port. */

static struct up_dev_s g_uart1priv =
{
  .uartbase       = LPC214X_UART1_BASE,
  .baud           = CONFIG_UART1_BAUD,
  .irq            = LPC214X_UART1_IRQ,
  .parity         = CONFIG_UART1_PARITY,
  .bits           = CONFIG_UART1_BITS,
  .stopbits2      = CONFIG_UART1_2STOP,
};

static uart_dev_t g_uart1port =
{
  .recv     =
  {
    .size   = CONFIG_UART1_RXBUFSIZE,
    .buffer = g_uart1rxbuffer,
  },
  .xmit     =
  {
    .size   = CONFIG_UART1_TXBUFSIZE,
    .buffer = g_uart1txbuffer,
  },
  .ops      = &g_uart_ops,
  .priv     = &g_uart1priv,
};

/* Now, which one with be tty0/console and which tty1? */

#if defined(CONFIG_UART0_SERIAL_CONSOLE)
#  define CONSOLE_DEV     g_uart0port
#  define TTYS0_DEV       g_uart0port
#  define TTYS1_DEV       g_uart1port
#elif defined(CONFIG_UART1_SERIAL_CONSOLE)
#  define CONSOLE_DEV     g_uart1port
#  define TTYS0_DEV       g_uart1port
#  define TTYS1_DEV       g_uart0port
#else
#  error "No CONFIG_UARTn_SERIAL_CONSOLE Setting"
#endif

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

/****************************************************************************
 * Name: up_serialin
 ****************************************************************************/

static inline uint8_t up_serialin(struct up_dev_s *priv, int offset)
{
  return getreg8(priv->uartbase + offset);
}

/****************************************************************************
 * Name: up_serialout
 ****************************************************************************/

static inline void up_serialout(struct up_dev_s *priv, int offset,
                                uint8_t value)
{
  putreg8(value, priv->uartbase + offset);
}

/****************************************************************************
 * Name: up_disableuartint
 ****************************************************************************/

static inline void up_disableuartint(struct up_dev_s *priv, uint8_t *ier)
{
  if (ier)
    {
      *ier = priv->ier & LPC214X_IER_ALLIE;
    }

  priv->ier &= ~LPC214X_IER_ALLIE;
  up_serialout(priv, LPC214X_UART_IER_OFFSET, priv->ier);
}

/****************************************************************************
 * Name: up_restoreuartint
 ****************************************************************************/

static inline void up_restoreuartint(struct up_dev_s *priv, uint8_t ier)
{
  priv->ier |= ier & LPC214X_IER_ALLIE;
  up_serialout(priv, LPC214X_UART_IER_OFFSET, priv->ier);
}

/****************************************************************************
 * Name: up_waittxready
 ****************************************************************************/

static inline void up_waittxready(struct up_dev_s *priv)
{
  int tmp;

  /* Limit how long we will wait for the TX available condition */

  for (tmp = 1000 ; tmp > 0 ; tmp--)
    {
      /* Check if the transmitter holding register (THR) is empty */

      if ((up_serialin(priv, LPC214X_UART_LSR_OFFSET) &
           LPC214X_LSR_THRE) != 0)
        {
          /* The THR is empty, return */

          break;
        }
    }
}

/****************************************************************************
 * Name: up_enablebreaks
 ****************************************************************************/

static inline void up_enablebreaks(struct up_dev_s *priv, bool enable)
{
  uint8_t lcr = up_serialin(priv, LPC214X_UART_LCR_OFFSET);

  if (enable)
    {
      lcr |= LPC214X_LCR_BREAK_ENABLE;
    }
  else
    {
      lcr &= ~LPC214X_LCR_BREAK_ENABLE;
    }

  up_serialout(priv, LPC214X_UART_LCR_OFFSET, lcr);
}

/****************************************************************************
 * Name: up_setup
 *
 * Description:
 *   Configure the UART baud, bits, parity, fifos, etc. This
 *   method is called the first time that the serial port is
 *   opened.
 *
 ****************************************************************************/

static int up_setup(struct uart_dev_s *dev)
{
#ifndef CONFIG_SUPPRESS_UART_CONFIG
  struct up_dev_s *priv = (struct up_dev_s *)dev->priv;
  uint16_t baud;
  uint8_t lcr;

  /* Clear fifos */

  up_serialout(priv, LPC214X_UART_FCR_OFFSET,
               (LPC214X_FCR_RX_FIFO_RESET | LPC214X_FCR_TX_FIFO_RESET));

  /* Set trigger */

  up_serialout(priv, LPC214X_UART_FCR_OFFSET,
               (LPC214X_FCR_FIFO_ENABLE | LPC214X_FCR_FIFO_TRIG14));

  /* Set up the IER */

  priv->ier = up_serialin(priv, LPC214X_UART_IER_OFFSET);

  /* Set up the LCR */

  lcr = 0;

  if (priv->bits == 7)
    {
      lcr |= LPC214X_LCR_CHAR_7;
    }
  else
    {
      lcr |= LPC214X_LCR_CHAR_8;
    }

  if (priv->stopbits2)
    {
      lcr |= LPC214X_LCR_STOP_2;
    }

  if (priv->parity == 1)
    {
      lcr |= LPC214X_LCR_PAR_ODD;
    }
  else if (priv->parity == 2)
    {
      lcr |= LPC214X_LCR_PAR_EVEN;
    }

  /* Enter DLAB=1 */

  up_serialout(priv, LPC214X_UART_LCR_OFFSET,
               (lcr | LPC214X_LCR_DLAB_ENABLE));

  /* Set the BAUD divisor */

  baud = UART_BAUD(priv->baud);
  up_serialout(priv, LPC214X_UART_DLM_OFFSET, baud >> 8);
  up_serialout(priv, LPC214X_UART_DLL_OFFSET, baud & 0xff);

  /* Clear DLAB */

  up_serialout(priv, LPC214X_UART_LCR_OFFSET, lcr);

  /* Configure the FIFOs */

  up_serialout(priv, LPC214X_UART_FCR_OFFSET,
               (LPC214X_FCR_FIFO_TRIG8 | LPC214X_FCR_TX_FIFO_RESET |
                LPC214X_FCR_RX_FIFO_RESET | LPC214X_FCR_FIFO_ENABLE));

  /* The NuttX serial driver waits for the first THRE interrupt before
   * sending serial data... However, it appears that the lpc214x hardware
   * does not generate that interrupt until a transition from not-empty
   * to empty.  So, the current kludge here is to send one NULL at
   * startup to kick things off.
   */

  up_serialout(priv, LPC214X_UART_THR_OFFSET, '\0');
#endif
  return OK;
}

/****************************************************************************
 * Name: up_shutdown
 *
 * Description:
 *   Disable the UART.  This method is called when the serial
 *   port is closed
 *
 ****************************************************************************/

static void up_shutdown(struct uart_dev_s *dev)
{
  struct up_dev_s *priv = (struct up_dev_s *)dev->priv;
  up_disableuartint(priv, NULL);
}

/****************************************************************************
 * Name: up_attach
 *
 * Description:
 *   Configure the UART to operation in interrupt driven mode.  This method
 *   is called when the serial port is opened.  Normally, this is just after
 *   the setup() method is called, however, the serial console may operate in
 *   a non-interrupt driven mode during the boot phase.
 *
 *   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 up_attach(struct uart_dev_s *dev)
{
  struct up_dev_s *priv = (struct up_dev_s *)dev->priv;
  int ret;

  /* Attach and enable the IRQ */

  ret = irq_attach(priv->irq, up_interrupt, dev);
  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 is received on the 'irq'.  It should call uart_xmitchars or
 *   uart_recvchars to perform the appropriate data transfers.  The
 *   interrupt handling logic must be able to map the 'arg' to the
 *   appropriate uart_dev_s structure in order to call these functions.
 *
 ****************************************************************************/

static int up_interrupt(int irq, void *context, void *arg)
{
  struct uart_dev_s *dev = (struct uart_dev_s *)arg;
  struct up_dev_s   *priv;
  uint8_t            status;
  int                passes;

  DEBUGASSERT(dev != NULL && dev->priv != NULL);
  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 there are pending
       * interrupts
       */

      if ((status & LPC214X_IIR_NO_INT) != 0)
        {
          /* Break out of the loop when there is no longer a
           * pending interrupt
           */

          break;
        }

      /* Handle the interrupt by its interrupt ID field */

      switch (status & LPC214X_IIR_MASK)
        {
          /* Handle incoming, receive bytes (with or without timeout) */

          case LPC214X_IIR_RDA_INT:
          case LPC214X_IIR_CTI_INT:
            {
              uart_recvchars(dev);
              break;
            }

          /* Handle outgoing, transmit bytes */

          case LPC214X_IIR_THRE_INT:
            {
              uart_xmitchars(dev);
              break;
            }

          /* Just clear modem status interrupts (UART1 only) */

          case LPC214X_IIR_MS_INT:
            {
              /* Read the modem status register (MSR) to clear */

              status = up_serialin(priv, LPC214X_UART_MSR_OFFSET);
              _info("MSR: %02x\n", status);
              break;
            }

          /* Just clear any line status interrupts */

          case LPC214X_IIR_RLS_INT:
            {
              /* Read the line status register (LSR) to clear */

              status = up_serialin(priv, LPC214X_UART_LSR_OFFSET);
              _info("LSR: %02x\n", status);
              break;
            }

          /* There should be no other values */

          default:
            {
              _err("ERROR: Unexpected IIR: %02x\n", status);
              break;
            }
        }
    }

    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)
    {
#ifdef CONFIG_SERIAL_TIOCSERGSTRUCT
    case TIOCSERGSTRUCT:
      {
         struct up_dev_s *user = (struct up_dev_s *)arg;
         if (!user)
           {
             ret = -EINVAL;
           }
         else
           {
             memcpy(user, dev, sizeof(struct up_dev_s));
           }
       }
       break;
#endif

    case TIOCSBRK:  /* BSD compatibility: Turn break on, unconditionally */
      {
        irqstate_t flags = enter_critical_section();
        up_enablebreaks(priv, true);
        leave_critical_section(flags);
      }
      break;

    case TIOCCBRK:  /* BSD compatibility: Turn break off, unconditionally */
      {
        irqstate_t flags;
        flags = enter_critical_section();
        up_enablebreaks(priv, false);
        leave_critical_section(flags);
      }
      break;

    default:
      ret = -ENOTTY;
      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 return 'status'.
 *
 ****************************************************************************/

static int up_receive(struct uart_dev_s *dev, unsigned int *status)
{
  struct up_dev_s *priv = (struct up_dev_s *)dev->priv;
  uint8_t rbr;

  *status = up_serialin(priv, LPC214X_UART_LSR_OFFSET);
  rbr     = 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, bool 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 bool 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, (uint8_t)ch);
}

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

static void up_txint(struct uart_dev_s *dev, bool 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 bool 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 bool 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 Functions
 ****************************************************************************/

#ifdef USE_EARLYSERIALINIT

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

void arm_earlyserialinit(void)
{
  /* Enable UART0 and 1 */

  uint32_t 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 one is the console */

  CONSOLE_DEV.isconsole = true;
  up_setup(&CONSOLE_DEV);
}
#endif

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

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

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

void up_putc(int ch)
{
  struct up_dev_s *priv = (struct up_dev_s *)CONSOLE_DEV.priv;
  uint8_t ier;

  up_disableuartint(priv, &ier);
  up_waittxready(priv);
  up_serialout(priv, LPC214X_UART_THR_OFFSET, (uint8_t)ch);

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

#else /* USE_SERIALDRIVER */

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

void up_putc(int ch)
{
  arm_lowputc(ch);
}

#endif /* USE_SERIALDRIVER */