/*
    ChibiOS/RT - Copyright (C) 2006,2007,2008,2009,2010 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    AT91SAM7/serial_lld.c
 * @brief   AT91SAM7 low level serial driver code.
 *
 * @addtogroup SERIAL
 * @{
 */

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

#if HAL_USE_SERIAL || defined(__DOXYGEN__)

#if SAM7_PLATFORM == SAM7S256

#define SAM7_USART0_RX    AT91C_PA5_RXD0
#define SAM7_USART0_TX    AT91C_PA6_TXD0
#define SAM7_USART1_RX    AT91C_PA21_RXD1
#define SAM7_USART1_TX    AT91C_PA22_TXD1
#define SAM7_DBGU_RX      AT91C_PA9_DRXD
#define SAM7_DBGU_TX      AT91C_PA10_DTXD

#elif SAM7_PLATFORM == SAM7X256

#define SAM7_USART0_RX    AT91C_PA0_RXD0
#define SAM7_USART0_TX    AT91C_PA1_TXD0
#define SAM7_USART1_RX    AT91C_PA5_RXD1
#define SAM7_USART1_TX    AT91C_PA6_TXD1
#define SAM7_DBGU_RX      AT91C_PA27_DRXD
#define SAM7_DBGU_TX      AT91C_PA28_DTXD

#else
#error "serial lines not defined for this SAM7 version"
#endif

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

#if USE_SAM7_USART0 || defined(__DOXYGEN__)
/** @brief USART0 serial driver identifier.*/
SerialDriver SD1;
#endif

#if USE_SAM7_USART1 || defined(__DOXYGEN__)
/** @brief USART1 serial driver identifier.*/
SerialDriver SD2;
#endif

#if USE_SAM7_DBGU_UART || defined(__DOXYGEN__)
/** @brief DBGU_UART serial driver identifier.*/
SerialDriver SD3;
#endif

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

/** @brief Driver default configuration.*/
static const SerialConfig default_config = {
  SERIAL_DEFAULT_BITRATE,
  AT91C_US_USMODE_NORMAL | AT91C_US_CLKS_CLOCK |
  AT91C_US_CHRL_8_BITS | AT91C_US_PAR_NONE | AT91C_US_NBSTOP_1_BIT
};

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

/**
 * @brief   USART initialization.
 *
 * @param[in] sdp       communication channel associated to the USART
 * @param[in] config    the architecture-dependent serial driver configuration
 */
static void usart_init(SerialDriver *sdp, const SerialConfig *config) {
  AT91PS_USART u = sdp->usart;

  /* Disables IRQ sources and stop operations.*/
  u->US_IDR = 0xFFFFFFFF;
  u->US_CR = AT91C_US_RSTRX | AT91C_US_RSTTX | AT91C_US_RSTSTA;

  /* New parameters setup.*/
  if (config->sc_mr & AT91C_US_OVER)
    u->US_BRGR = MCK / (config->sc_speed * 8);
  else
    u->US_BRGR = MCK / (config->sc_speed * 16);
  u->US_MR = config->sc_mr;
  u->US_RTOR = 0;
  u->US_TTGR = 0;

  /* Enables operations and IRQ sources.*/
  u->US_CR = AT91C_US_RXEN | AT91C_US_TXEN | AT91C_US_DTREN | AT91C_US_RTSEN;
  u->US_IER = AT91C_US_RXRDY | AT91C_US_OVRE | AT91C_US_FRAME | AT91C_US_PARE |
              AT91C_US_RXBRK;
}

/**
 * @brief   USART de-initialization.
 *
 * @param[in] u         pointer to an USART I/O block
 */
static void usart_deinit(AT91PS_USART u) {

  /* Disables IRQ sources and stop operations.*/
  u->US_IDR = 0xFFFFFFFF;
  u->US_CR = AT91C_US_RSTRX | AT91C_US_RSTTX | AT91C_US_RSTSTA;
  u->US_MR = 0;
  u->US_RTOR = 0;
  u->US_TTGR = 0;
}

/**
 * @brief   Error handling routine.
 *
 * @param[in] err       USART CSR register value
 * @param[in] sdp       communication channel associated to the USART
 */
static void set_error(SerialDriver *sdp, AT91_REG csr) {
  sdflags_t sts = 0;

  if (csr & AT91C_US_OVRE)
    sts |= SD_OVERRUN_ERROR;
  if (csr & AT91C_US_PARE)
    sts |= SD_PARITY_ERROR;
  if (csr & AT91C_US_FRAME)
    sts |= SD_FRAMING_ERROR;
  if (csr & AT91C_US_RXBRK)
    sts |= SD_BREAK_DETECTED;
  chSysLockFromIsr();
  sdAddFlagsI(sdp, sts);
  chSysUnlockFromIsr();
}

#if defined(__GNUC__)
__attribute__((noinline))
#endif
#if !USE_SAM7_DBGU_UART
static
#endif
/**
 * @brief   Common IRQ handler.
 *
 * @param[in] sdp       communication channel associated to the USART
 */
void sd_lld_serve_interrupt(SerialDriver *sdp) {
  uint32_t csr;
  AT91PS_USART u = sdp->usart;

  csr = u->US_CSR;
  if (csr & AT91C_US_RXRDY) {
    chSysLockFromIsr();
    sdIncomingDataI(sdp, u->US_RHR);
    chSysUnlockFromIsr();
  }
  if ((u->US_IMR & AT91C_US_TXRDY) && (csr & AT91C_US_TXRDY)) {
    msg_t b;

    chSysLockFromIsr();
    b = chOQGetI(&sdp->oqueue);
    if (b < Q_OK) {
      chEvtBroadcastI(&sdp->oevent);
      u->US_IDR = AT91C_US_TXRDY;
    }
    else
      u->US_THR = b;
    chSysUnlockFromIsr();
  }
  csr &= (AT91C_US_OVRE | AT91C_US_FRAME | AT91C_US_PARE | AT91C_US_RXBRK);
  if (csr != 0) {
    set_error(sdp, csr);
    u->US_CR = AT91C_US_RSTSTA;
  }
  AT91C_BASE_AIC->AIC_EOICR = 0;
}

#if USE_SAM7_USART0 || defined(__DOXYGEN__)
static void notify1(void) {

  AT91C_BASE_US0->US_IER = AT91C_US_TXRDY;
}
#endif

#if USE_SAM7_USART1 || defined(__DOXYGEN__)
static void notify2(void) {

  AT91C_BASE_US1->US_IER = AT91C_US_TXRDY;
}
#endif

#if USE_SAM7_DBGU_UART || defined(__DOXYGEN__)
static void notify3(void) {

  AT91C_BASE_DBGU->DBGU_IER = AT91C_US_TXRDY;
}
#endif

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

#if USE_SAM7_USART0 || defined(__DOXYGEN__)
/**
 * @brief   USART0 interrupt handler.
 *
 * @isr
 */
CH_IRQ_HANDLER(USART0IrqHandler) {

  CH_IRQ_PROLOGUE();
  sd_lld_serve_interrupt(&SD1);
  AT91C_BASE_AIC->AIC_EOICR = 0;
  CH_IRQ_EPILOGUE();
}
#endif

#if USE_SAM7_USART1 || defined(__DOXYGEN__)
/**
 * @brief   USART1 interrupt handler.
 *
 * @isr
 */
CH_IRQ_HANDLER(USART1IrqHandler) {

  CH_IRQ_PROLOGUE();
  sd_lld_serve_interrupt(&SD2);
  AT91C_BASE_AIC->AIC_EOICR = 0;
  CH_IRQ_EPILOGUE();
}
#endif

/* note - DBGU_UART IRQ is the SysIrq in board.c
   since it's not vectored separately by the AIC.*/

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

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

#if USE_SAM7_USART0
  sdObjectInit(&SD1, NULL, notify1);
  SD1.usart = AT91C_BASE_US0;
  AT91C_BASE_PIOA->PIO_PDR   = SAM7_USART0_RX | SAM7_USART0_TX;
  AT91C_BASE_PIOA->PIO_ASR   = SAM7_USART0_RX | SAM7_USART0_TX;
  AT91C_BASE_PIOA->PIO_PPUDR = SAM7_USART0_RX | SAM7_USART0_TX;
  AIC_ConfigureIT(AT91C_ID_US0,
                  AT91C_AIC_SRCTYPE_HIGH_LEVEL | SAM7_USART0_PRIORITY,
                  USART0IrqHandler);
#endif

#if USE_SAM7_USART1
  sdObjectInit(&SD2, NULL, notify2);
  SD2.usart = AT91C_BASE_US1;
  AT91C_BASE_PIOA->PIO_PDR   = SAM7_USART1_RX | SAM7_USART1_TX;
  AT91C_BASE_PIOA->PIO_ASR   = SAM7_USART1_RX | SAM7_USART1_TX;
  AT91C_BASE_PIOA->PIO_PPUDR = SAM7_USART1_RX | SAM7_USART1_TX;
  AIC_ConfigureIT(AT91C_ID_US1,
                  AT91C_AIC_SRCTYPE_HIGH_LEVEL | SAM7_USART1_PRIORITY,
                  USART1IrqHandler);
#endif

#if USE_SAM7_DBGU_UART
  sdObjectInit(&SD3, NULL, notify3);
  /* this is a little cheap, but OK for now since there's enough overlap
     between dbgu and usart register maps.  it means we can reuse all the
     same usart interrupt handling and config that already exists.*/
  SD3.usart = (AT91PS_USART)AT91C_BASE_DBGU;
  AT91C_BASE_PIOA->PIO_PDR   = SAM7_DBGU_RX | SAM7_DBGU_TX;
  AT91C_BASE_PIOA->PIO_ASR   = SAM7_DBGU_RX | SAM7_DBGU_TX;
  AT91C_BASE_PIOA->PIO_PPUDR = SAM7_DBGU_RX | SAM7_DBGU_TX;
#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 USE_SAM7_USART0
    if (&SD1 == sdp) {
      /* Starts the clock and clears possible sources of immediate interrupts.*/
      AT91C_BASE_PMC->PMC_PCER = (1 << AT91C_ID_US0);
      /* Enables associated interrupt vector.*/
      AIC_EnableIT(AT91C_ID_US0);
    }
#endif
#if USE_SAM7_USART1
    if (&SD2 == sdp) {
      /* Starts the clock and clears possible sources of immediate interrupts.*/
      AT91C_BASE_PMC->PMC_PCER = (1 << AT91C_ID_US1);
      /* Enables associated interrupt vector.*/
      AIC_EnableIT(AT91C_ID_US1);
    }
#endif
  /* Note - no explicit start for SD3 (DBGU_UART) since it's not included
     in the AIC or PMC.*/
  }
  usart_init(sdp, config);
}

/**
 * @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) {
    usart_deinit(sdp->usart);
#if USE_SAM7_USART0
    if (&SD1 == sdp) {
      AT91C_BASE_PMC->PMC_PCDR = (1 << AT91C_ID_US0);
      AIC_DisableIT(AT91C_ID_US0);
      return;
    }
#endif
#if USE_SAM7_USART1
    if (&SD2 == sdp) {
      AT91C_BASE_PMC->PMC_PCDR = (1 << AT91C_ID_US1);
      AIC_DisableIT(AT91C_ID_US1);
      return;
    }
#endif
#if USE_SAM7_DBGU_UART
    if (&SD3 == sdp) {
      AT91C_BASE_DBGU->DBGU_IDR = 0xFFFFFFFF;
      return;
    }
#endif
  }
}

#endif /* HAL_USE_SERIAL */

/** @} */