/*
    Copyright (C) 2015 Fabio Utzig

    Licensed 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.
*/

/**
 * @file    serial_lld.c
 * @brief   NRF51822 serial subsystem low level driver source.
 *
 * @addtogroup SERIAL
 * @{
 */

#include "hal.h"

#if (HAL_USE_SERIAL == TRUE) || defined(__DOXYGEN__)

#include "nrf51.h"

/*===========================================================================*/
/* Driver local definitions.                                                 */
/*===========================================================================*/

#define INVALID_BAUDRATE 0xFFFFFFFF
#define INVALID_PIN      0xFF

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

/** @brief USART1 serial driver identifier.*/
#if (NRF51_SERIAL_USE_UART0 == TRUE) || defined(__DOXYGEN__)
SerialDriver SD1;
#endif

/*===========================================================================*/
/* Driver local variables and types.                                         */
/*===========================================================================*/

/**
 * @brief   Driver default configuration.
 */
static const SerialConfig default_config = {
  .speed = 38400,
  .tx_pin = INVALID_PIN,
  .rx_pin = INVALID_PIN,
};

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

/*
 * @brief Maps a baudrate speed to a BAUDRATE register value.
 */
static uint32_t regval_from_baudrate(uint32_t speed)
{
  switch (speed) {
  case 1200:    return 0x0004F000;
  case 2400:    return 0x0009D000;
  case 4800:    return 0x0013B000;
  case 9600:    return 0x00275000;
  case 14400:   return 0x003B0000;
  case 19200:   return 0x004EA000;
  case 28800:   return 0x0075F000;
  case 38400:   return 0x009D5000;
  case 57600:   return 0x00EBF000;
  case 76800:   return 0x013A9000;
  case 115200:  return 0x01D7E000;
  case 230400:  return 0x03AFB000;
  case 250000:  return 0x04000000;
  case 460800:  return 0x075F7000;
  case 921600:  return 0x0EBEDFA4;
  case 1000000: return 0x10000000;
  }
  return INVALID_BAUDRATE;
}


/**
 * @brief   Driver output notification.
 */
#if NRF51_SERIAL_USE_UART0 || defined(__DOXYGEN__)
static void notify1(io_queue_t *qp)
{
  (void)qp;

  msg_t b = oqGetI(&SD1.oqueue);
  if (b < Q_OK) {
    chnAddFlagsI(&SD1, CHN_OUTPUT_EMPTY);
    return;
  }
  SD1.thread = chThdGetSelfX();
  NRF_UART0->TXD = b;
  chEvtWaitAny((eventmask_t) 1);
}
#endif


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

#if NRF51_SERIAL_USE_UART0 || defined(__DOXYGEN__)
OSAL_IRQ_HANDLER(Vector48) {

  OSAL_IRQ_PROLOGUE();

  if (NRF_UART0->EVENTS_RXDRDY) {
    NRF_UART0->EVENTS_RXDRDY = 0;
    osalSysLockFromISR();
    if (iqIsEmptyI(&SD1.iqueue))
      chnAddFlagsI(&SD1, CHN_INPUT_AVAILABLE);
    if (iqPutI(&SD1.iqueue, NRF_UART0->RXD) < Q_OK)
      chnAddFlagsI(&SD1, SD_OVERRUN_ERROR);
    osalSysUnlockFromISR();
  }

  if (NRF_UART0->EVENTS_TXDRDY) {
    NRF_UART0->EVENTS_TXDRDY = 0;
    osalSysLockFromISR();
    chEvtSignalI(SD1.thread, (eventmask_t) 1);
    osalSysUnlockFromISR();
  }

  /* TODO: Error handling for EVENTS_ERROR */

  OSAL_IRQ_EPILOGUE();
}
#endif

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

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

#if NRF51_SERIAL_USE_UART0 == TRUE
  sdObjectInit(&SD1, NULL, notify1);
#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 (sdp->state == SD_STOP) {

#if NRF51_SERIAL_USE_UART0 == TRUE
    if (sdp == &SD1) {
      uint32_t regval;

      /* TODO: Add support for CTS/RTS! */

      /* Configure PINs */
      NRF_UART0->PSELRTS = ~0;
      NRF_UART0->PSELCTS = ~0;
      if (config->tx_pin != INVALID_PIN) {
        palSetPadMode(IOPORT1, config->tx_pin, PAL_MODE_OUTPUT_PUSHPULL);
        NRF_UART0->PSELTXD = config->tx_pin;
      }
      if (config->rx_pin != INVALID_PIN) {
        palSetPadMode(IOPORT1, config->rx_pin, PAL_MODE_INPUT);
        NRF_UART0->PSELRXD = config->rx_pin;
      }

      regval = regval_from_baudrate(config->speed);
      osalDbgAssert(regval != INVALID_BAUDRATE, "invalid baudrate speed");
      NRF_UART0->BAUDRATE = regval;

      /* Enable interrupts for RX, TX and ERROR */
      NRF_UART0->INTENSET = 0x284;

      NRF_UART0->EVENTS_RXDRDY = 0;
      NRF_UART0->EVENTS_TXDRDY = 0;

      nvicEnableVector(UART0_IRQn, 12);

      NRF_UART0->ENABLE = 4;
      NRF_UART0->TASKS_STARTRX = 1;
      NRF_UART0->TASKS_STARTTX = 1;
    }
#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 (sdp->state == SD_READY) {

#if NRF51_SERIAL_USE_UART0 == TRUE
    if (&SD1 == sdp) {
      nvicDisableVector(UART0_IRQn);
    }
#endif

  }
}

#endif /* HAL_USE_SERIAL == TRUE */

/** @} */