mayhem-firmware/firmware/chibios/os/hal/platforms/LPC8xx/serial_lld.c

/*
    ChibiOS/RT - Copyright (C) 2006-2013 Giovanni Di Sirio

    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    LPC8xx/serial_lld.c
 * @brief   LPC8xx low level serial driver code.
 *
 * @addtogroup SERIAL
 * @{
 */

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

#if HAL_USE_SERIAL || defined(__DOXYGEN__)

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

#if LPC8xx_SERIAL_USE_UART0 || defined(__DOXYGEN__)
/** @brief UART0 serial driver identifier.*/
SerialDriver SD1;
#endif

#if LPC8xx_SERIAL_USE_UART1 || defined(__DOXYGEN__)
/** @brief UART1 serial driver identifier.*/
SerialDriver SD2;
#endif

#if LPC8xx_SERIAL_USE_UART2 || defined(__DOXYGEN__)
/** @brief UART2 serial driver identifier.*/
SerialDriver SD3;
#endif

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

/** @brief Driver default configuration.*/
static const SerialConfig default_config = {
  SERIAL_DEFAULT_BITRATE,
  (CFG_DL8 | CFG_NOPARITY | CFG_STOP1)
};

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

/**
 * @brief   Error handling routine.
 *
 * @param[in] sdp       communication channel associated to the UART
 * @param[in] err       UART STAT register value
 */
static void set_error(SerialDriver *sdp, IOREG32 err) {
  flagsmask_t sts = 0;

  if (err & STAT_OVERRUN)
    sts |= SD_OVERRUN_ERROR;
  if (err & STAT_PARITYERR)
    sts |= SD_PARITY_ERROR;
  if (err & STAT_FRAMERR)
    sts |= SD_FRAMING_ERROR;
  if (err & STAT_RXBRK)
    sts |= SD_BREAK_DETECTED;

  chSysLockFromIsr();
  chnAddFlagsI(sdp, sts);
  chSysUnlockFromIsr();  
}

/**
 * @brief   Common IRQ handler.
 * @note    Tries hard to clear all the pending interrupt sources, we don't
 *          want to go through the whole ISR and have another interrupt soon
 *          after.
 *
 * @param[in] u         pointer to an UART I/O block
 * @param[in] sdp       communication channel associated to the UART
 */
static void serve_interrupt(SerialDriver *sdp) {
  LPC_USART_TypeDef *u = sdp->uart;

  while (u->INTSTAT) {

    if (u->INTSTAT & STAT_RXRDY) {
      chSysLockFromIsr();
      if (chIQIsEmptyI(&sdp->iqueue))
        chnAddFlagsI(sdp, CHN_INPUT_AVAILABLE);
      if (chIQPutI(&sdp->iqueue, u->RXDATA) < Q_OK)
        chnAddFlagsI(sdp, SD_OVERRUN_ERROR);
      chSysUnlockFromIsr();
    }

    if (u->INTSTAT & STAT_TXRDY) {
      msg_t b;

      chSysLockFromIsr();
      b = chOQGetI(&sdp->oqueue);
      chSysUnlockFromIsr();

      if (b < Q_OK) {
        u->INTENCLR = STAT_TXRDY;
        chSysLockFromIsr();
        chnAddFlagsI(sdp, CHN_OUTPUT_EMPTY);
        chSysUnlockFromIsr();
        break;
      }
      else {
         u->TXDATA = b;
      }
    }

    if (u->INTSTAT & (STAT_OVERRUN | STAT_DELTARXBRK |
                      STAT_FRAMERR | STAT_PARITYERR) ) {
      IOREG32 stat = u->STAT;
      set_error(sdp, stat);
      u->STAT = stat;
    }

  }
}

/**
 * @brief   Attempts a TX preload.
 */
static void preload(SerialDriver *sdp) {
  LPC_USART_TypeDef *u = sdp->uart;

  if (u->STAT & STAT_TXIDLE) {
    msg_t b = chOQGetI(&sdp->oqueue);
    if (b < Q_OK) {
      chnAddFlagsI(sdp, CHN_OUTPUT_EMPTY);
      return;
    }
    u->TXDATA = b;
  }
  u->INTENSET = STAT_TXRDY;
}

/**
 * @brief   Driver output notification.
 */
#if LPC8xx_SERIAL_USE_UART0 || defined(__DOXYGEN__)
static void notify1(GenericQueue *qp) {

  (void)qp;
  preload(&SD1);
}
#endif

#if LPC8xx_SERIAL_USE_UART1 || defined(__DOXYGEN__)
static void notify2(GenericQueue *qp) {

  (void)qp;
  preload(&SD2);
}
#endif

#if LPC8xx_SERIAL_USE_UART2 || defined(__DOXYGEN__)
static void notify3(GenericQueue *qp) {

  (void)qp;
  preload(&SD3);
}
#endif

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

/**
 * @brief   UARTn IRQ handlers.
 *
 * @isr
 */
#if LPC8xx_SERIAL_USE_UART0 || defined(__DOXYGEN__)
CH_IRQ_HANDLER(Vector4C) {

  CH_IRQ_PROLOGUE();
  serve_interrupt( &SD1 );
  CH_IRQ_EPILOGUE();
}
#endif
#if LPC8xx_SERIAL_USE_UART1 || defined(__DOXYGEN__)
CH_IRQ_HANDLER(Vector50) {

  CH_IRQ_PROLOGUE();
  serve_interrupt( &SD2 );
  CH_IRQ_EPILOGUE();
}
#endif
#if LPC8xx_SERIAL_USE_UART2 || defined(__DOXYGEN__)
CH_IRQ_HANDLER(Vector54) {

  CH_IRQ_PROLOGUE();
  serve_interrupt( &SD3 );
  CH_IRQ_EPILOGUE();
}
#endif

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

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

#if LPC8xx_SERIAL_USE_UART0
  sdObjectInit(&SD1, NULL, notify1);
  SD1.uart = LPC_USART0;
#endif

#if LPC8xx_SERIAL_USE_UART1
  sdObjectInit(&SD2, NULL, notify2);
  SD2.uart = LPC_USART1;
#endif

#if LPC8xx_SERIAL_USE_UART2
  sdObjectInit(&SD3, NULL, notify3);
  SD3.uart = LPC_USART2;
#endif

  /* Reset fractional baudrate generator */
  LPC_SYSCON->PRESETCTRL &= ~(1<<2);
  LPC_SYSCON->PRESETCTRL |=  (1<<2);

  LPC_SYSCON->UARTCLKDIV  = LPC8xx_SERIAL_UARTCLKDIV;
  LPC_SYSCON->UARTFRGDIV  = LPC8xx_SERIAL_UARTFRGDIV;
  LPC_SYSCON->UARTFRGMULT = LPC8xx_SERIAL_UARTFRGMULT;

}

/**
 * @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 LPC8xx_SERIAL_USE_UART0
    if (&SD1 == sdp) {
      LPC_SYSCON->SYSAHBCLKCTRL |= (1<<14);           // Enable Clk
      LPC_SYSCON->PRESETCTRL &= ~(1<<3);              // Reset peripheral
      LPC_SYSCON->PRESETCTRL |=  (1<<3);
      nvicEnableVector(UART0_IRQn,
                       CORTEX_PRIORITY_MASK(LPC8xx_SERIAL_UART0_IRQ_PRIORITY));
    }
#endif

#if LPC8xx_SERIAL_USE_UART1
    if (&SD2 == sdp) {
      LPC_SYSCON->SYSAHBCLKCTRL |= (1<<15);           // Enable Clk
      LPC_SYSCON->PRESETCTRL &= ~(1<<4);              // Reset peripheral
      LPC_SYSCON->PRESETCTRL |=  (1<<4);
      nvicEnableVector(UART1_IRQn,
                       CORTEX_PRIORITY_MASK(LPC8xx_SERIAL_UART1_IRQ_PRIORITY));
    }
#endif

#if LPC8xx_SERIAL_USE_UART2
    if (&SD3 == sdp) {
      LPC_SYSCON->SYSAHBCLKCTRL |= (1<<16);           // Enable Clk
      LPC_SYSCON->PRESETCTRL &= ~(1<<5);              // Reset peripheral
      LPC_SYSCON->PRESETCTRL |=  (1<<5);
      nvicEnableVector(UART2_IRQn,
                       CORTEX_PRIORITY_MASK(LPC8xx_SERIAL_UART2_IRQ_PRIORITY));
    }
#endif

  }

  sdp->uart->BRG = (LPC8xx_SERIAL_U_PCLK / (config->sc_speed << 4)) -1;
  sdp->uart->INTENSET = STAT_FRAMERR | STAT_OVERRUN |
                        STAT_PARITYERR | STAT_DELTARXBRK |
                        STAT_RXRDY; 
  sdp->uart->CFG = config->sc_cfg | CFG_ENA;
}

/**
 * @brief   Low level serial driver stop.
 * @details De-initializes the UART, 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) {
    sdp->uart->INTENCLR = STAT_TXRDY | STAT_RXRDY; 
    sdp->uart->CFG = 0;

#if LPC8xx_SERIAL_USE_UART0
    if (&SD1 == sdp) {
      LPC_SYSCON->SYSAHBCLKCTRL &= ~(1<<12);
      nvicDisableVector(UART0_IRQn);
      return;
    }
#endif

#if LPC8xx_SERIAL_USE_UART1
    if (&SD2 == sdp) {
      LPC_SYSCON->SYSAHBCLKCTRL &= ~(1<<13);
      nvicDisableVector(UART1_IRQn);
      return;
    }
#endif

#if LPC8xx_SERIAL_USE_UART2
    if (&SD3 == sdp) {
      LPC_SYSCON->SYSAHBCLKCTRL &= ~(1<<14);
      nvicDisableVector(UART2_IRQn);
      return;
    }
#endif

  }
}

#endif /* HAL_USE_SERIAL */

/** @} */