/*
    ChibiOS/RT - Copyright (C) 2006,2007,2008,2009,2010,
                 2011,2012,2013 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    STM32/can_lld.c
 * @brief   STM32 CAN subsystem low level driver source.
 *
 * @addtogroup CAN
 * @{
 */

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

#if HAL_USE_CAN || defined(__DOXYGEN__)

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

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

/** @brief CAN1 driver identifier.*/
#if STM32_CAN_USE_CAN1 || defined(__DOXYGEN__)
CANDriver CAND1;
#endif

/** @brief CAN2 driver identifier.*/
#if STM32_CAN_USE_CAN2 || defined(__DOXYGEN__)
CANDriver CAND2;
#endif

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

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

/**
 * @brief   Programs the filters.
 *
 * @param[in] can2sb    number of the first filter assigned to CAN2
 * @param[in] num       number of entries in the filters array, if zero then
 *                      a default filter is programmed
 * @param[in] cfp       pointer to the filters array, can be @p NULL if
 *                      (num == 0)
 *
 * @notapi
 */
static void can_lld_set_filters(uint32_t can2sb,
                         uint32_t num,
                         const CANFilter *cfp) {

  /* Temporarily enabling CAN1 clock.*/
  rccEnableCAN1(FALSE);

  /* Filters initialization.*/
  CAN1->FMR = (CAN1->FMR & 0xFFFF0000) | (can2sb << 8) | CAN_FMR_FINIT;
  if (num > 0) {
    uint32_t i, fmask;

    /* All filters cleared.*/
    CAN1->FA1R = 0;
    CAN1->FM1R = 0;
    CAN1->FS1R = 0;
    CAN1->FFA1R = 0;
    for (i = 0; i < STM32_CAN_MAX_FILTERS; i++) {
      CAN1->sFilterRegister[i].FR1 = 0;
      CAN1->sFilterRegister[i].FR2 = 0;
    }

    /* Scanning the filters array.*/
    for (i = 0; i < num; i++) {
      fmask = 1 << cfp->filter;
      if (cfp->mode)
        CAN1->FM1R |= fmask;
      if (cfp->scale)
        CAN1->FS1R |= fmask;
      if (cfp->assignment)
        CAN1->FFA1R |= fmask;
      CAN1->sFilterRegister[cfp->filter].FR1 = cfp->register1;
      CAN1->sFilterRegister[cfp->filter].FR2 = cfp->register2;
      CAN1->FA1R |= fmask;
      cfp++;
    }
  }
  else {
    /* Setting up a single default filter that enables everything for both
       CANs.*/
    CAN1->sFilterRegister[0].FR1 = 0;
    CAN1->sFilterRegister[0].FR2 = 0;
    CAN1->sFilterRegister[can2sb].FR1 = 0;
    CAN1->sFilterRegister[can2sb].FR2 = 0;
    CAN1->FM1R = 0;
    CAN1->FFA1R = 0;
    CAN1->FS1R = 1 | (1 << can2sb);
    CAN1->FA1R = 1 | (1 << can2sb);
  }
  CAN1->FMR &= ~CAN_FMR_FINIT;

  /* Clock disabled, it will be enabled again in can_lld_start().*/
  rccDisableCAN1(FALSE);
}

/**
 * @brief   Common TX ISR handler.
 *
 * @param[in] canp      pointer to the @p CANDriver object
 *
 * @notapi
 */
static void can_lld_tx_handler(CANDriver *canp) {

  /* No more events until a message is transmitted.*/
  canp->can->TSR = CAN_TSR_RQCP0 | CAN_TSR_RQCP1 | CAN_TSR_RQCP2;
  chSysLockFromIsr();
  while (chSemGetCounterI(&canp->txsem) < 0)
    chSemSignalI(&canp->txsem);
  chEvtBroadcastFlagsI(&canp->txempty_event, CAN_MAILBOX_TO_MASK(1));
  chSysUnlockFromIsr();
}

/**
 * @brief   Common RX0 ISR handler.
 *
 * @param[in] canp      pointer to the @p CANDriver object
 *
 * @notapi
 */
static void can_lld_rx0_handler(CANDriver *canp) {
  uint32_t rf0r;

  rf0r = canp->can->RF0R;
  if ((rf0r & CAN_RF0R_FMP0) > 0) {
    /* No more receive events until the queue 0 has been emptied.*/
    canp->can->IER &= ~CAN_IER_FMPIE0;
    chSysLockFromIsr();
    while (chSemGetCounterI(&canp->rxsem) < 0)
      chSemSignalI(&canp->rxsem);
    chEvtBroadcastFlagsI(&canp->rxfull_event, CAN_MAILBOX_TO_MASK(1));
    chSysUnlockFromIsr();
  }
  if ((rf0r & CAN_RF0R_FOVR0) > 0) {
    /* Overflow events handling.*/
    canp->can->RF0R = CAN_RF0R_FOVR0;
    chSysLockFromIsr();
    chEvtBroadcastFlagsI(&canp->error_event, CAN_OVERFLOW_ERROR);
    chSysUnlockFromIsr();
  }
}

/**
 * @brief   Common RX1 ISR handler.
 *
 * @param[in] canp      pointer to the @p CANDriver object
 *
 * @notapi
 */
static void can_lld_rx1_handler(CANDriver *canp) {
  uint32_t rf1r;

  rf1r = canp->can->RF1R;
  if ((rf1r & CAN_RF1R_FMP1) > 0) {
    /* No more receive events until the queue 0 has been emptied.*/
    canp->can->IER &= ~CAN_IER_FMPIE1;
    chSysLockFromIsr();
    while (chSemGetCounterI(&canp->rxsem) < 0)
      chSemSignalI(&canp->rxsem);
    chEvtBroadcastFlagsI(&canp->rxfull_event, CAN_MAILBOX_TO_MASK(1));
    chSysUnlockFromIsr();
  }
  if ((rf1r & CAN_RF1R_FOVR1) > 0) {
    /* Overflow events handling.*/
    canp->can->RF1R = CAN_RF1R_FOVR1;
    chSysLockFromIsr();
    chEvtBroadcastFlagsI(&canp->error_event, CAN_OVERFLOW_ERROR);
    chSysUnlockFromIsr();
  }
}

/**
 * @brief   Common SCE ISR handler.
 *
 * @param[in] canp      pointer to the @p CANDriver object
 *
 * @notapi
 */
static void can_lld_sce_handler(CANDriver *canp) {
  uint32_t msr;

  msr = canp->can->MSR;
  canp->can->MSR = CAN_MSR_ERRI | CAN_MSR_WKUI | CAN_MSR_SLAKI;
  /* Wakeup event.*/
  if (msr & CAN_MSR_WKUI) {
    canp->state = CAN_READY;
    canp->can->MCR &= ~CAN_MCR_SLEEP;
    chSysLockFromIsr();
    chEvtBroadcastI(&canp->wakeup_event);
    chSysUnlockFromIsr();
  }
  /* Error event.*/
  if (msr & CAN_MSR_ERRI) {
    flagsmask_t flags;
    uint32_t esr = canp->can->ESR;

    canp->can->ESR &= ~CAN_ESR_LEC;
    flags = (flagsmask_t)(esr & 7);
    if ((esr & CAN_ESR_LEC) > 0)
      flags |= CAN_FRAMING_ERROR;

    chSysLockFromIsr();
    /* The content of the ESR register is copied unchanged in the upper
       half word of the listener flags mask.*/
    chEvtBroadcastFlagsI(&canp->error_event, flags | (flagsmask_t)(esr << 16));
    chSysUnlockFromIsr();
  }
}

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

#if STM32_CAN_USE_CAN1 || defined(__DOXYGEN__)
/**
 * @brief   CAN1 TX interrupt handler.
 *
 * @isr
 */
CH_IRQ_HANDLER(STM32_CAN1_TX_HANDLER) {

  CH_IRQ_PROLOGUE();

  can_lld_tx_handler(&CAND1);

  CH_IRQ_EPILOGUE();
}

/*
 * @brief   CAN1 RX0 interrupt handler.
 *
 * @isr
 */
CH_IRQ_HANDLER(STM32_CAN1_RX0_HANDLER) {

  CH_IRQ_PROLOGUE();

  can_lld_rx0_handler(&CAND1);

  CH_IRQ_EPILOGUE();
}

/**
 * @brief   CAN1 RX1 interrupt handler.
 *
 * @isr
 */
CH_IRQ_HANDLER(STM32_CAN1_RX1_HANDLER) {

  CH_IRQ_PROLOGUE();

  can_lld_rx1_handler(&CAND1);

  CH_IRQ_EPILOGUE();
}

/**
 * @brief   CAN1 SCE interrupt handler.
 *
 * @isr
 */
CH_IRQ_HANDLER(STM32_CAN1_SCE_HANDLER) {

  CH_IRQ_PROLOGUE();

  can_lld_sce_handler(&CAND1);

  CH_IRQ_EPILOGUE();
}
#endif /* STM32_CAN_USE_CAN1 */

#if STM32_CAN_USE_CAN2 || defined(__DOXYGEN__)
/**
 * @brief   CAN2 TX interrupt handler.
 *
 * @isr
 */
CH_IRQ_HANDLER(STM32_CAN2_TX_HANDLER) {

  CH_IRQ_PROLOGUE();

  can_lld_tx_handler(&CAND2);

  CH_IRQ_EPILOGUE();
}

/*
 * @brief   CAN2 RX0 interrupt handler.
 *
 * @isr
 */
CH_IRQ_HANDLER(STM32_CAN2_RX0_HANDLER) {

  CH_IRQ_PROLOGUE();

  can_lld_rx0_handler(&CAND2);

  CH_IRQ_EPILOGUE();
}

/**
 * @brief   CAN2 RX1 interrupt handler.
 *
 * @isr
 */
CH_IRQ_HANDLER(STM32_CAN2_RX1_HANDLER) {

  CH_IRQ_PROLOGUE();

  can_lld_rx1_handler(&CAND2);

  CH_IRQ_EPILOGUE();
}

/**
 * @brief   CAN2 SCE interrupt handler.
 *
 * @isr
 */
CH_IRQ_HANDLER(STM32_CAN2_SCE_HANDLER) {

  CH_IRQ_PROLOGUE();

  can_lld_sce_handler(&CAND2);

  CH_IRQ_EPILOGUE();
}
#endif /* STM32_CAN_USE_CAN2 */

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

/**
 * @brief   Low level CAN driver initialization.
 *
 * @notapi
 */
void can_lld_init(void) {

#if STM32_CAN_USE_CAN1
  /* Driver initialization.*/
  canObjectInit(&CAND1);
  CAND1.can = CAN1;
#endif
#if STM32_CAN_USE_CAN2
  /* Driver initialization.*/
  canObjectInit(&CAND2);
  CAND2.can = CAN2;
#endif

  /* Filters initialization.*/
#if STM32_HAS_CAN2
  can_lld_set_filters(STM32_CAN_MAX_FILTERS / 2, 0, NULL);
#else
  can_lld_set_filters(STM32_CAN_MAX_FILTERS, 0, NULL);
#endif

}

/**
 * @brief   Configures and activates the CAN peripheral.
 *
 * @param[in] canp      pointer to the @p CANDriver object
 *
 * @notapi
 */
void can_lld_start(CANDriver *canp) {

  /* Clock activation.*/
#if STM32_CAN_USE_CAN1
  if (&CAND1 == canp) {
    nvicEnableVector(STM32_CAN1_TX_NUMBER,
                     CORTEX_PRIORITY_MASK(STM32_CAN_CAN1_IRQ_PRIORITY));
    nvicEnableVector(STM32_CAN1_RX0_NUMBER,
                     CORTEX_PRIORITY_MASK(STM32_CAN_CAN1_IRQ_PRIORITY));
    nvicEnableVector(STM32_CAN1_RX1_NUMBER,
                     CORTEX_PRIORITY_MASK(STM32_CAN_CAN1_IRQ_PRIORITY));
    nvicEnableVector(STM32_CAN1_SCE_NUMBER,
                     CORTEX_PRIORITY_MASK(STM32_CAN_CAN1_IRQ_PRIORITY));
    rccEnableCAN1(FALSE);
  }
#endif
#if STM32_CAN_USE_CAN2
  if (&CAND2 == canp) {
    nvicEnableVector(STM32_CAN2_TX_NUMBER,
                     CORTEX_PRIORITY_MASK(STM32_CAN_CAN2_IRQ_PRIORITY));
    nvicEnableVector(STM32_CAN2_RX0_NUMBER,
                     CORTEX_PRIORITY_MASK(STM32_CAN_CAN2_IRQ_PRIORITY));
    nvicEnableVector(STM32_CAN2_RX1_NUMBER,
                     CORTEX_PRIORITY_MASK(STM32_CAN_CAN2_IRQ_PRIORITY));
    nvicEnableVector(STM32_CAN2_SCE_NUMBER,
                     CORTEX_PRIORITY_MASK(STM32_CAN_CAN2_IRQ_PRIORITY));
    rccEnableCAN2(FALSE);
  }
#endif

  /* Entering initialization mode. */
  canp->state = CAN_STARTING;
  canp->can->MCR = CAN_MCR_INRQ;
  while ((canp->can->MSR & CAN_MSR_INAK) == 0)
    chThdSleepS(1);
  /* BTR initialization.*/
  canp->can->BTR = canp->config->btr;
  /* MCR initialization.*/
  canp->can->MCR = canp->config->mcr;

  /* Interrupt sources initialization.*/
  canp->can->IER = CAN_IER_TMEIE  | CAN_IER_FMPIE0 | CAN_IER_FMPIE1 |
                   CAN_IER_WKUIE  | CAN_IER_ERRIE  | CAN_IER_LECIE  |
                   CAN_IER_BOFIE  | CAN_IER_EPVIE  | CAN_IER_EWGIE  |
                   CAN_IER_FOVIE0 | CAN_IER_FOVIE1;
}

/**
 * @brief   Deactivates the CAN peripheral.
 *
 * @param[in] canp      pointer to the @p CANDriver object
 *
 * @notapi
 */
void can_lld_stop(CANDriver *canp) {

  /* If in ready state then disables the CAN peripheral.*/
  if (canp->state == CAN_READY) {
#if STM32_CAN_USE_CAN1
    if (&CAND1 == canp) {
      CAN1->MCR = 0x00010002;                   /* Register reset value.    */
      CAN1->IER = 0x00000000;                   /* All sources disabled.    */
      nvicDisableVector(STM32_CAN1_TX_NUMBER);
      nvicDisableVector(STM32_CAN1_RX0_NUMBER);
      nvicDisableVector(STM32_CAN1_RX1_NUMBER);
      nvicDisableVector(STM32_CAN1_SCE_NUMBER);
      rccDisableCAN1(FALSE);
    }
#endif
#if STM32_CAN_USE_CAN2
    if (&CAND2 == canp) {
      CAN2->MCR = 0x00010002;                   /* Register reset value.    */
      CAN2->IER = 0x00000000;                   /* All sources disabled.    */
      nvicDisableVector(STM32_CAN2_TX_NUMBER);
      nvicDisableVector(STM32_CAN2_RX0_NUMBER);
      nvicDisableVector(STM32_CAN2_RX1_NUMBER);
      nvicDisableVector(STM32_CAN2_SCE_NUMBER);
      rccDisableCAN2(FALSE);
    }
#endif
  }
}

/**
 * @brief   Determines whether a frame can be transmitted.
 *
 * @param[in] canp      pointer to the @p CANDriver object
 * @param[in] mailbox   mailbox number, @p CAN_ANY_MAILBOX for any mailbox
 *
 * @return              The queue space availability.
 * @retval FALSE        no space in the transmit queue.
 * @retval TRUE         transmit slot available.
 *
 * @notapi
 */
bool_t can_lld_is_tx_empty(CANDriver *canp, canmbx_t mailbox) {

  switch (mailbox) {
  case CAN_ANY_MAILBOX:
    return (canp->can->TSR & CAN_TSR_TME) != 0;
  case 1:
    return (canp->can->TSR & CAN_TSR_TME0) != 0;
  case 2:
    return (canp->can->TSR & CAN_TSR_TME1) != 0;
  case 3:
    return (canp->can->TSR & CAN_TSR_TME2) != 0;
  default:
    return FALSE;
  }
}

/**
 * @brief   Inserts a frame into the transmit queue.
 *
 * @param[in] canp      pointer to the @p CANDriver object
 * @param[in] ctfp      pointer to the CAN frame to be transmitted
 * @param[in] mailbox   mailbox number,  @p CAN_ANY_MAILBOX for any mailbox
 *
 * @notapi
 */
void can_lld_transmit(CANDriver *canp,
                      canmbx_t mailbox,
                      const CANTxFrame *ctfp) {
  uint32_t tir;
  CAN_TxMailBox_TypeDef *tmbp;

  /* Pointer to a free transmission mailbox.*/
  switch (mailbox) {
  case CAN_ANY_MAILBOX:
    tmbp = &canp->can->sTxMailBox[(canp->can->TSR & CAN_TSR_CODE) >> 24];
    break;
  case 1:
    tmbp = &canp->can->sTxMailBox[0];
    break;
  case 2:
    tmbp = &canp->can->sTxMailBox[1];
    break;
  case 3:
    tmbp = &canp->can->sTxMailBox[2];
    break;
  default:
    return;
  }

  /* Preparing the message.*/
  if (ctfp->IDE)
    tir = ((uint32_t)ctfp->EID << 3) | ((uint32_t)ctfp->RTR << 1) |
          CAN_TI0R_IDE;
  else
    tir = ((uint32_t)ctfp->SID << 21) | ((uint32_t)ctfp->RTR << 1);
  tmbp->TDTR = ctfp->DLC;
  tmbp->TDLR = ctfp->data32[0];
  tmbp->TDHR = ctfp->data32[1];
  tmbp->TIR  = tir | CAN_TI0R_TXRQ;
}

/**
 * @brief   Determines whether a frame has been received.
 *
 * @param[in] canp      pointer to the @p CANDriver object
 * @param[in] mailbox   mailbox number, @p CAN_ANY_MAILBOX for any mailbox
 *
 * @return              The queue space availability.
 * @retval FALSE        no space in the transmit queue.
 * @retval TRUE         transmit slot available.
 *
 * @notapi
 */
bool_t can_lld_is_rx_nonempty(CANDriver *canp, canmbx_t mailbox) {

  switch (mailbox) {
  case CAN_ANY_MAILBOX:
    return (canp->can->RF0R & (CAN_RF0R_FMP0 | CAN_RF1R_FMP1)) != 0;
  case 1:
    return (canp->can->RF0R & CAN_RF0R_FMP0) != 0;
  case 2:
    return (canp->can->RF1R & CAN_RF1R_FMP1) != 0;
  default:
    return FALSE;
  }
}

/**
 * @brief   Receives a frame from the input queue.
 *
 * @param[in] canp      pointer to the @p CANDriver object
 * @param[in] mailbox   mailbox number, @p CAN_ANY_MAILBOX for any mailbox
 * @param[out] crfp     pointer to the buffer where the CAN frame is copied
 *
 * @notapi
 */
void can_lld_receive(CANDriver *canp,
                     canmbx_t mailbox,
                     CANRxFrame *crfp) {
  uint32_t rir, rdtr;

  if (mailbox == CAN_ANY_MAILBOX) {
    if ((canp->can->RF0R & CAN_RF0R_FMP0) != 0)
      mailbox = 1;
    else if ((canp->can->RF1R & CAN_RF1R_FMP1) != 0)
      mailbox = 2;
    else {
      /* Should not happen, do nothing.*/
      return;
    }
  }
  switch (mailbox) {
  case 1:
    /* Fetches the message.*/
    rir  = canp->can->sFIFOMailBox[0].RIR;
    rdtr = canp->can->sFIFOMailBox[0].RDTR;
    crfp->data32[0] = canp->can->sFIFOMailBox[0].RDLR;
    crfp->data32[1] = canp->can->sFIFOMailBox[0].RDHR;

    /* Releases the mailbox.*/
    canp->can->RF0R = CAN_RF0R_RFOM0;

    /* If the queue is empty re-enables the interrupt in order to generate
       events again.*/
    if ((canp->can->RF0R & CAN_RF0R_FMP0) == 0)
      canp->can->IER |= CAN_IER_FMPIE0;
    break;
  case 2:
    /* Fetches the message.*/
    rir  = canp->can->sFIFOMailBox[1].RIR;
    rdtr = canp->can->sFIFOMailBox[1].RDTR;
    crfp->data32[0] = canp->can->sFIFOMailBox[1].RDLR;
    crfp->data32[1] = canp->can->sFIFOMailBox[1].RDHR;

    /* Releases the mailbox.*/
    canp->can->RF1R = CAN_RF1R_RFOM1;

    /* If the queue is empty re-enables the interrupt in order to generate
       events again.*/
    if ((canp->can->RF1R & CAN_RF1R_FMP1) == 0)
      canp->can->IER |= CAN_IER_FMPIE1;
    break;
  default:
    /* Should not happen, do nothing.*/
    return;
  }

  /* Decodes the various fields in the RX frame.*/
  crfp->RTR = (rir & CAN_RI0R_RTR) >> 1;
  crfp->IDE = (rir & CAN_RI0R_IDE) >> 2;
  if (crfp->IDE)
    crfp->EID = rir >> 3;
  else
    crfp->SID = rir >> 21;
  crfp->DLC = rdtr & CAN_RDT0R_DLC;
  crfp->FMI = (uint8_t)(rdtr >> 8);
  crfp->TIME = (uint16_t)(rdtr >> 16);
}

#if CAN_USE_SLEEP_MODE || defined(__DOXYGEN__)
/**
 * @brief   Enters the sleep mode.
 *
 * @param[in] canp      pointer to the @p CANDriver object
 *
 * @notapi
 */
void can_lld_sleep(CANDriver *canp) {

  canp->can->MCR |= CAN_MCR_SLEEP;
}

/**
 * @brief   Enforces leaving the sleep mode.
 *
 * @param[in] canp      pointer to the @p CANDriver object
 *
 * @notapi
 */
void can_lld_wakeup(CANDriver *canp) {

  canp->can->MCR &= ~CAN_MCR_SLEEP;
}
#endif /* CAN_USE_SLEEP_MODE */

/**
 * @brief   Programs the filters.
 * @note    This is an STM32-specific API.
 *
 * @param[in] can2sb    number of the first filter assigned to CAN2
 * @param[in] num       number of entries in the filters array, if zero then
 *                      a default filter is programmed
 * @param[in] cfp       pointer to the filters array, can be @p NULL if
 *                      (num == 0)
 *
 * @api
 */
void canSTM32SetFilters(uint32_t can2sb, uint32_t num, const CANFilter *cfp) {

  chDbgCheck((can2sb > 1) && (can2sb < STM32_CAN_MAX_FILTERS) &&
             (num < STM32_CAN_MAX_FILTERS),
             "canSTM32SetFilters");

#if STM32_CAN_USE_CAN1
  chDbgAssert(CAND1.state == CAN_STOP,
              "canSTM32SetFilters(), #1", "invalid state");
#endif
#if STM32_CAN_USE_CAN2
  chDbgAssert(CAND2.state == CAN_STOP,
              "canSTM32SetFilters(), #2", "invalid state");
#endif

  can_lld_set_filters(can2sb, num, cfp);
}

#endif /* HAL_USE_CAN */

/** @} */