/*
    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    serial_usb.c
 * @brief   Serial over USB Driver code.
 *
 * @addtogroup SERIAL_USB
 * @{
 */

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

#include "usb_cdc.h"

#if HAL_USE_SERIAL_USB || defined(__DOXYGEN__)

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

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

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

/*
 * Current Line Coding.
 */
static cdc_linecoding_t linecoding = {
  {0x00, 0x96, 0x00, 0x00},             /* 38400.                           */
  LC_STOP_1, LC_PARITY_NONE, 8
};

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

/*
 * Interface implementation.
 */

static size_t write(void *ip, const uint8_t *bp, size_t n) {

  return chOQWriteTimeout(&((SerialUSBDriver *)ip)->oqueue, bp,
                          n, TIME_INFINITE);
}

static size_t read(void *ip, uint8_t *bp, size_t n) {

  return chIQReadTimeout(&((SerialUSBDriver *)ip)->iqueue, bp,
                         n, TIME_INFINITE);
}

static msg_t put(void *ip, uint8_t b) {

  return chOQPutTimeout(&((SerialUSBDriver *)ip)->oqueue, b, TIME_INFINITE);
}

static msg_t get(void *ip) {

  return chIQGetTimeout(&((SerialUSBDriver *)ip)->iqueue, TIME_INFINITE);
}

static msg_t putt(void *ip, uint8_t b, systime_t timeout) {

  return chOQPutTimeout(&((SerialUSBDriver *)ip)->oqueue, b, timeout);
}

static msg_t gett(void *ip, systime_t timeout) {

  return chIQGetTimeout(&((SerialUSBDriver *)ip)->iqueue, timeout);
}

static size_t writet(void *ip, const uint8_t *bp, size_t n, systime_t time) {

  return chOQWriteTimeout(&((SerialUSBDriver *)ip)->oqueue, bp, n, time);
}

static size_t readt(void *ip, uint8_t *bp, size_t n, systime_t time) {

  return chIQReadTimeout(&((SerialUSBDriver *)ip)->iqueue, bp, n, time);
}

static chnflags_t getflags(void *ip) {
  _chn_get_and_clear_flags_impl(ip);
}

static const struct SerialUSBDriverVMT vmt = {
  write, read, put, get,
  putt, gett, writet, readt,
  getflags
};

/**
 * @brief   Notification of data removed from the input queue.
 */
static void inotify(GenericQueue *qp) {
  size_t n, maxsize;
  SerialUSBDriver *sdup = chQGetLink(qp);

  /* If the USB driver is not in the appropriate state then transactions
     must not be started.*/
  if (usbGetDriverStateI(sdup->config->usbp) != USB_ACTIVE)
    return;

  /* If there is in the queue enough space to hold at least one packet and
     a transaction is not yet started then a new transaction is started for
     the available space.*/
  maxsize = sdup->config->usbp->epc[USB_CDC_DATA_AVAILABLE_EP]->out_maxsize;
  if (!usbGetReceiveStatusI(sdup->config->usbp, USB_CDC_DATA_AVAILABLE_EP) &&
      ((n = chIQGetEmptyI(&sdup->iqueue)) >= maxsize)) {
    chSysUnlock();

    n = (n / maxsize) * maxsize;
    usbPrepareQueuedReceive(sdup->config->usbp,
                            USB_CDC_DATA_AVAILABLE_EP,
                            &sdup->iqueue, n);

    chSysLock();
    usbStartReceiveI(sdup->config->usbp, USB_CDC_DATA_AVAILABLE_EP);
  }
}

/**
 * @brief   Notification of data inserted into the output queue.
 */
static void onotify(GenericQueue *qp) {
  size_t n;
  SerialUSBDriver *sdup = chQGetLink(qp);

  /* If the USB driver is not in the appropriate state then transactions
     must not be started.*/
  if (usbGetDriverStateI(sdup->config->usbp) != USB_ACTIVE)
    return;

  /* If there is not an ongoing transaction and the output queue contains
     data then a new transaction is started.*/
  if (!usbGetTransmitStatusI(sdup->config->usbp, USB_CDC_DATA_REQUEST_EP) &&
      ((n = chOQGetFullI(&sdup->oqueue)) > 0)) {
    chSysUnlock();

    usbPrepareQueuedTransmit(sdup->config->usbp,
                             USB_CDC_DATA_REQUEST_EP,
                             &sdup->oqueue, n);

    chSysLock();
    usbStartTransmitI(sdup->config->usbp, USB_CDC_DATA_REQUEST_EP);
  }
}

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

/**
 * @brief   Serial Driver initialization.
 * @note    This function is implicitly invoked by @p halInit(), there is
 *          no need to explicitly initialize the driver.
 *
 * @init
 */
void sduInit(void) {
}

/**
 * @brief   Initializes a generic full duplex driver object.
 * @details The HW dependent part of the initialization has to be performed
 *          outside, usually in the hardware initialization code.
 *
 * @param[out] sdup     pointer to a @p SerialUSBDriver structure
 *
 * @init
 */
void sduObjectInit(SerialUSBDriver *sdup) {

  sdup->vmt = &vmt;
  chEvtInit(&sdup->event);
  sdup->flags = CHN_NO_ERROR;
  sdup->state = SDU_STOP;
  chIQInit(&sdup->iqueue, sdup->ib, SERIAL_USB_BUFFERS_SIZE, inotify, sdup);
  chOQInit(&sdup->oqueue, sdup->ob, SERIAL_USB_BUFFERS_SIZE, onotify, sdup);
}

/**
 * @brief   Configures and starts the driver.
 *
 * @param[in] sdup      pointer to a @p SerialUSBDriver object
 * @param[in] config    the serial over USB driver configuration
 *
 * @api
 */
void sduStart(SerialUSBDriver *sdup, const SerialUSBConfig *config) {

  chDbgCheck(sdup != NULL, "sduStart");

  chSysLock();
  chDbgAssert((sdup->state == SDU_STOP) || (sdup->state == SDU_READY),
              "sduStart(), #1",
              "invalid state");
  sdup->config = config;
  config->usbp->param = sdup;
  sdup->state = SDU_READY;
  chSysUnlock();
  usbStart(config->usbp, &config->usb_config);
}

/**
 * @brief   Stops the driver.
 * @details Any thread waiting on the driver's queues will be awakened with
 *          the message @p Q_RESET.
 *
 * @param[in] sdup      pointer to a @p SerialUSBDriver object
 *
 * @api
 */
void sduStop(SerialUSBDriver *sdup) {

  chDbgCheck(sdup != NULL, "sdStop");

  chSysLock();
  chDbgAssert((sdup->state == SDU_STOP) || (sdup->state == SDU_READY),
              "sduStop(), #1",
              "invalid state");
  sdup->state = SDU_STOP;
  chSysUnlock();
  usbStop(sdup->config->usbp);
}

/**
 * @brief   USB device configured handler.
 *
 * @param[in] usbp      pointer to the @p USBDriver object
 *
 * @iclass
 */
void sduConfigureHookI(USBDriver *usbp) {
  SerialUSBDriver *sdup = usbp->param;

  sdup->flags = CHN_NO_ERROR;
  chIQResetI(&sdup->iqueue);
  chOQResetI(&sdup->oqueue);
  chnAddFlagsI(sdup, CHN_CONNECTED);
}

/**
 * @brief   Default requests hook.
 * @details Applications wanting to use the Serial over USB driver can use
 *          this function as requests hook in the USB configuration.
 *          The following requests are emulated:
 *          - CDC_GET_LINE_CODING.
 *          - CDC_SET_LINE_CODING.
 *          - CDC_SET_CONTROL_LINE_STATE.
 *          .
 *
 * @param[in] usbp      pointer to the @p USBDriver object
 * @return              The hook status.
 * @retval TRUE         Message handled internally.
 * @retval FALSE        Message not handled.
 */
bool_t sduRequestsHook(USBDriver *usbp) {

  if ((usbp->setup[0] & USB_RTYPE_TYPE_MASK) == USB_RTYPE_TYPE_CLASS) {
    switch (usbp->setup[1]) {
    case CDC_GET_LINE_CODING:
      usbSetupTransfer(usbp, (uint8_t *)&linecoding, sizeof(linecoding), NULL);
      return TRUE;
    case CDC_SET_LINE_CODING:
      usbSetupTransfer(usbp, (uint8_t *)&linecoding, sizeof(linecoding), NULL);
      return TRUE;
    case CDC_SET_CONTROL_LINE_STATE:
      /* Nothing to do, there are no control lines.*/
      usbSetupTransfer(usbp, NULL, 0, NULL);
      return TRUE;
    default:
      return FALSE;
    }
  }
  return FALSE;
}

/**
 * @brief   Default data transmitted callback.
 * @details The application must use this function as callback for the IN
 *          data endpoint.
 *
 * @param[in] usbp      pointer to the @p USBDriver object
 * @param[in] ep        endpoint number
 */
void sduDataTransmitted(USBDriver *usbp, usbep_t ep) {
  size_t n;
  SerialUSBDriver *sdup = usbp->param;

  (void)ep;

  chSysLockFromIsr();
  chnAddFlagsI(sdup, CHN_OUTPUT_EMPTY);

  if ((n = chOQGetFullI(&sdup->oqueue)) > 0) {
    /* The endpoint cannot be busy, we are in the context of the callback,
       so it is safe to transmit without a check.*/
    chSysUnlockFromIsr();

    usbPrepareQueuedTransmit(usbp,
                             USB_CDC_DATA_REQUEST_EP,
                             &sdup->oqueue, n);

    chSysLockFromIsr();
    usbStartTransmitI(usbp, USB_CDC_DATA_REQUEST_EP);
  }

  chSysUnlockFromIsr();
}

/**
 * @brief   Default data received callback.
 * @details The application must use this function as callback for the OUT
 *          data endpoint.
 *
 * @param[in] usbp      pointer to the @p USBDriver object
 * @param[in] ep        endpoint number
 */
void sduDataReceived(USBDriver *usbp, usbep_t ep) {
  size_t n, maxsize;
  SerialUSBDriver *sdup = usbp->param;

  (void)ep;

  chSysLockFromIsr();
  chnAddFlagsI(sdup, CHN_INPUT_AVAILABLE);

  /* Writes to the input queue can only happen when there is enough space
     to hold at least one packet.*/
  maxsize = usbp->epc[USB_CDC_DATA_AVAILABLE_EP]->out_maxsize;
  if ((n = chIQGetEmptyI(&sdup->iqueue)) >= maxsize) {
    /* The endpoint cannot be busy, we are in the context of the callback,
       so a packet is in the buffer for sure.*/
    chSysUnlockFromIsr();

    n = (n / maxsize) * maxsize;
    usbPrepareQueuedReceive(usbp,
                            USB_CDC_DATA_AVAILABLE_EP,
                            &sdup->iqueue, n);

    chSysLockFromIsr();
    usbStartReceiveI(usbp, USB_CDC_DATA_AVAILABLE_EP);
  }

  chSysUnlockFromIsr();
}

/**
 * @brief   Default data received callback.
 * @details The application must use this function as callback for the IN
 *          interrupt endpoint.
 *
 * @param[in] usbp      pointer to the @p USBDriver object
 * @param[in] ep        endpoint number
 */
void sduInterruptTransmitted(USBDriver *usbp, usbep_t ep) {

  (void)usbp;
  (void)ep;
}

#endif /* HAL_USE_SERIAL */

/** @} */