path: root/os/hal/platforms/AVR/serial_lld.c

/*
    ChibiOS/RT - Copyright (C) 2006,2007,2008,2009,2010,
                 2011,2012 Giovanni Di Sirio.

    This file is part of ChibiOS/RT.

    ChibiOS/RT is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 3 of the License, or
    (at your option) any later version.

    ChibiOS/RT is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

/**
 * @file    AVR/serial_lld.c
 * @brief   AVR low level serial driver code.
 *
 * @addtogroup SERIAL
 * @{
 */

#include "ch.h"
#include "hal.h"

#if HAL_USE_SERIAL || defined(__DOXYGEN__)

/*===========================================================================*/
/* Driver exported variables.                                                */
/*===========================================================================*/

/**
 * @brief   USART0 serial driver identifier.
 * @note    The name does not follow the convention used in the other ports
 *          (COMn) because a name conflict with the AVR headers.
 */
#if USE_AVR_USART0 || defined(__DOXYGEN__)
SerialDriver SD1;
#endif

/**
 * @brief   USART1 serial driver identifier.
 * @note    The name does not follow the convention used in the other ports
 *          (COMn) because a name conflict with the AVR headers.
 */
#if USE_AVR_USART1 || defined(__DOXYGEN__)
SerialDriver SD2;
#endif

/*===========================================================================*/
/* Driver local variables.                                                   */
/*===========================================================================*/

/**
 * @brief   Driver default configuration.
 */
static const SerialConfig default_config = {
  UBRR(SERIAL_DEFAULT_BITRATE),
  USART_CHAR_SIZE_8
};

/*===========================================================================*/
/* Driver local functions.                                                   */
/*===========================================================================*/

static void set_error(uint8_t sra, SerialDriver *sdp) {
  chnflags_t sts = 0;
  uint8_t dor = 0;
  uint8_t upe = 0;
  uint8_t fe = 0;

#if USE_AVR_USART0
  if (&SD1 == sdp) {
    dor = (1 << DOR0);
    upe = (1 << UPE0);
    fe = (1 << FE0);
  }
#endif

#if USE_AVR_USART1
  if (&SD2 == sdp) {
    dor = (1 << DOR1);
    upe = (1 << UPE1);
    fe = (1 << FE1);
  }
#endif

  if (sra & dor)
    sts |= SD_OVERRUN_ERROR;
  if (sra & upe)
    sts |= SD_PARITY_ERROR;
  if (sra & fe)
    sts |= SD_FRAMING_ERROR;
  chSysLockFromIsr();
  chnAddFlagsI(sdp, sts);
  chSysUnlockFromIsr();
}

#if USE_AVR_USART0 || defined(__DOXYGEN__)
static void notify1(GenericQueue *qp) {

  (void)qp;
  UCSR0B |= (1 << UDRIE0);
}

/**
 * @brief   USART0 initialization.
 *
 * @param[in] config    the architecture-dependent serial driver configuration
 */
static void usart0_init(const SerialConfig *config) {

  UBRR0L = config->sc_brr;
  UBRR0H = config->sc_brr >> 8;
  UCSR0A = 0;
  UCSR0B = (1 << RXEN0) | (1 << TXEN0) | (1 << RXCIE0);
  switch (config->sc_bits_per_char) {
  case USART_CHAR_SIZE_5:
    UCSR0C = 0;
    break;
  case USART_CHAR_SIZE_6:
    UCSR0C = (1 << UCSZ00);
    break;
  case USART_CHAR_SIZE_7:
    UCSR0C = (1 << UCSZ01);
    break;
  case USART_CHAR_SIZE_9:
    UCSR0B |= (1 << UCSZ02);
    UCSR0C = (1 << UCSZ00) | (1 << UCSZ01);
    break;
  case USART_CHAR_SIZE_8:
  default:
    UCSR0C = (1 << UCSZ00) | (1 << UCSZ01);
  }
}

/**
 * @brief   USART0 de-initialization.
 */
static void usart0_deinit(void) {

  UCSR0A = 0;
  UCSR0B = 0;
  UCSR0C = 0;
}
#endif

#if USE_AVR_USART1 || defined(__DOXYGEN__)
static void notify2(GenericQueue *qp) {

  (void)qp;
  UCSR1B |= (1 << UDRIE1);
}

/**
 * @brief   USART1 initialization.
 *
 * @param[in] config    the architecture-dependent serial driver configuration
 */
static void usart1_init(const SerialConfig *config) {

  UBRR1L = config->sc_brr;
  UBRR1H = config->sc_brr >> 8;
  UCSR1A = 0;
  UCSR1B = (1 << RXEN1) | (1 << TXEN1) | (1 << RXCIE1);
  switch (config->sc_bits_per_char) {
  case USART_CHAR_SIZE_5:
    UCSR1C = 0;
    break;
  case USART_CHAR_SIZE_6:
    UCSR1C = (1 << UCSZ10);
    break;
  case USART_CHAR_SIZE_7:
    UCSR1C = (1 << UCSZ11);
    break;
  case USART_CHAR_SIZE_9:
    UCSR1B |= (1 << UCSZ12);
    UCSR1C = (1 << UCSZ10) | (1 << UCSZ11);
    break;
  case USART_CHAR_SIZE_8:
  default:
    UCSR1C = (1 << UCSZ10) | (1 << UCSZ11);
  }
}

/**
 * @brief   USART1 de-initialization.
 */
static void usart1_deinit(void) {

  UCSR1A = 0;
  UCSR1B = 0;
  UCSR1C = 0;
}
#endif

/*===========================================================================*/
/* Driver interrupt handlers.                                                */
/*===========================================================================*/

#if USE_AVR_USART0 || defined(__DOXYGEN__)
/**
 * @brief   USART0 RX interrupt handler.
 *
 * @isr
 */
CH_IRQ_HANDLER(USART0_RX_vect) {
  uint8_t sra;

  CH_IRQ_PROLOGUE();

  sra = UCSR0A;
  if (sra & ((1 << DOR0) | (1 << UPE0) | (1 << FE0)))
    set_error(sra, &SD1);
  chSysLockFromIsr();
  sdIncomingDataI(&SD1, UDR0);
  chSysUnlockFromIsr();

  CH_IRQ_EPILOGUE();
}

/**
 * @brief   USART0 TX interrupt handler.
 *
 * @isr
 */
CH_IRQ_HANDLER(USART0_UDRE_vect) {
  msg_t b;

  CH_IRQ_PROLOGUE();

  chSysLockFromIsr();
  b = sdRequestDataI(&SD1);
  chSysUnlockFromIsr();
  if (b < Q_OK)
    UCSR0B &= ~(1 << UDRIE0);
  else
    UDR0 = b;

  CH_IRQ_EPILOGUE();
}
#endif /* USE_AVR_USART0 */

#if USE_AVR_USART1 || defined(__DOXYGEN__)
/**
 * @brief   USART1 RX interrupt handler.
 *
 * @isr
 */
CH_IRQ_HANDLER(USART1_RX_vect) {
  uint8_t sra;

  CH_IRQ_PROLOGUE();

  sra = UCSR1A;
  if (sra & ((1 << DOR1) | (1 << UPE1) | (1 << FE1)))
    set_error(sra, &SD2);
  chSysLockFromIsr();
  sdIncomingDataI(&SD2, UDR1);
  chSysUnlockFromIsr();

  CH_IRQ_EPILOGUE();
}

/**
 * @brief   USART1 TX interrupt handler.
 *
 * @isr
 */
CH_IRQ_HANDLER(USART1_UDRE_vect) {
  msg_t b;

  CH_IRQ_PROLOGUE();

  chSysLockFromIsr();
  b = sdRequestDataI(&SD2);
  chSysUnlockFromIsr();
  if (b < Q_OK)
    UCSR1B &= ~(1 << UDRIE1);
  else
    UDR1 = b;

  CH_IRQ_EPILOGUE();
}
#endif /* USE_AVR_USART1 */

/*===========================================================================*/
/* Driver exported functions.                                                */
/*===========================================================================*/

/**
 * @brief   Low level serial driver initialization.
 *
 * @notapi
 */
void sd_lld_init(void) {

#if USE_AVR_USART0
  sdObjectInit(&SD1, NULL, notify1);
#endif
#if USE_AVR_USART1
  sdObjectInit(&SD2, NULL, notify2);
#endif
}

/**
 * @brief   Low level serial driver configuration and (re)start.
 *
 * @param[in] sdp       pointer to a @p SerialDriver object
 * @param[in] config    the architecture-dependent serial driver configuration.
 *                      If this parameter is set to @p NULL then a default
 *                      configuration is used.
 *
 * @notapi
 */
void sd_lld_start(SerialDriver *sdp, const SerialConfig *config) {

  if (config == NULL)
    config = &default_config;

#if USE_AVR_USART0
  if (&SD1 == sdp) {
    usart0_init(config);
    return;
  }
#endif
#if USE_AVR_USART1
  if (&SD2 == sdp) {
    usart1_init(config);
    return;
  }
#endif
}

/**
 * @brief   Low level serial driver stop.
 * @details De-initializes the USART, stops the associated clock, resets the
 *          interrupt vector.
 *
 * @param[in] sdp       pointer to a @p SerialDriver object
 *
 * @notapi
 */
void sd_lld_stop(SerialDriver *sdp) {

#if USE_AVR_USART0
  if (&SD1 == sdp)
    usart0_deinit();
#endif
#if USE_AVR_USART1
  if (&SD2 == sdp)
    usart1_deinit();
#endif
}

#endif /* HAL_USE_SERIAL */

/** @} */