/*
             LUFA Library
     Copyright (C) Dean Camera, 2017.

  dean [at] fourwalledcubicle [dot] com
           www.lufa-lib.org
*/

/*
  Copyright 2017  Dean Camera (dean [at] fourwalledcubicle [dot] com)

  Permission to use, copy, modify, distribute, and sell this
  software and its documentation for any purpose is hereby granted
  without fee, provided that the above copyright notice appear in
  all copies and that both that the copyright notice and this
  permission notice and warranty disclaimer appear in supporting
  documentation, and that the name of the author not be used in
  advertising or publicity pertaining to distribution of the
  software without specific, written prior permission.

  The author disclaims all warranties with regard to this
  software, including all implied warranties of merchantability
  and fitness.  In no event shall the author be liable for any
  special, indirect or consequential damages or any damages
  whatsoever resulting from loss of use, data or profits, whether
  in an action of contract, negligence or other tortious action,
  arising out of or in connection with the use or performance of
  this software.
*/

/** \file
 *
 *  Header file for USARTDescriptors.c.
 */

#ifndef _USART_DESCRIPTORS_H_
#define _USART_DESCRIPTORS_H_

	/* Includes: */
		#include <avr/pgmspace.h>

		#include <LUFA/Drivers/USB/USB.h>

		#include "Config/AppConfig.h"

	/* Macros: */
		/** Endpoint address of the CDC device-to-host notification IN endpoint. */
		#define CDC_NOTIFICATION_EPADDR        (ENDPOINT_DIR_IN  | 2)

		/** Endpoint address of the CDC device-to-host data IN endpoint. */
		#define CDC_TX_EPADDR                  (ENDPOINT_DIR_IN  | 3)

		/** Endpoint address of the CDC host-to-device data OUT endpoint. */
		#define CDC_RX_EPADDR                  (ENDPOINT_DIR_OUT | 4)

		/** Size in bytes of the CDC device-to-host notification IN endpoint. */
		#define CDC_NOTIFICATION_EPSIZE        8

		/** Size in bytes of the CDC data IN and OUT endpoints. */
		#define CDC_TXRX_EPSIZE                16

	/* Type Defines: */
		/** Type define for the device configuration descriptor structure. This must be defined in the
		 *  application code, as the configuration descriptor contains several sub-descriptors which
		 *  vary between devices, and which describe the device's usage to the host.
		 */
		typedef struct
		{
/*
    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    chsem.c
 * @brief   Semaphores code.
 *
 * @addtogroup semaphores
 * @details Semaphores related APIs and services.
 *
 *          <h2>Operation mode</h2>
 *          Semaphores are a flexible synchronization primitive, ChibiOS/RT
 *          implements semaphores in their "counting semaphores" variant as
 *          defined by Edsger Dijkstra plus several enhancements like:
 *          - Wait operation with timeout.
 *          - Reset operation.
 *          - Atomic wait+signal operation.
 *          - Return message from the wait operation (OK, RESET, TIMEOUT).
 *          .
 *          The binary semaphores variant can be easily implemented using
 *          counting semaphores.<br>
 *          Operations defined for semaphores:
 *          - <b>Signal</b>: The semaphore counter is increased and if the
 *            result is non-positive then a waiting thread is removed from
 *            the semaphore queue and made ready for execution.
 *          - <b>Wait</b>: The semaphore counter is decreased and if the result
 *            becomes negative the thread is queued in the semaphore and
 *            suspended.
 *          - <b>Reset</b>: The semaphore counter is reset to a non-negative
 *            value and all the threads in the queue are released.
 *          .
 *          Semaphores can be used as guards for mutual exclusion zones
 *          (note that mutexes are recommended for this kind of use) but
 *          also have other uses, queues guards and counters for example.<br>
 *          Semaphores usually use a FIFO queuing strategy but it is possible
 *          to make them order threads by priority by enabling
 *          @p CH_USE_SEMAPHORES_PRIORITY in @p chconf.h.
 * @pre     In order to use the semaphore APIs the @p CH_USE_SEMAPHORES
 *          option must be enabled in @p chconf.h.
 * @{
 */

#include "ch.h"

#if CH_USE_SEMAPHORES || defined(__DOXYGEN__)

#if CH_USE_SEMAPHORES_PRIORITY
#define sem_insert(tp, qp) prio_insert(tp, qp)
#else
#define sem_insert(tp, qp) queue_insert(tp, qp)
#endif

/**
 * @brief   Initializes a semaphore with the specified counter value.
 *
 * @param[out] sp       pointer to a @p Semaphore structure
 * @param[in] n         initial value of the semaphore counter. Must be
 *                      non-negative.
 *
 * @init
 */
void chSemInit(Semaphore *sp, cnt_t n) {

  chDbgCheck((sp != NULL) && (n >= 0), "chSemInit");

  queue_init(&sp->s_queue);
  sp->s_cnt = n;
}

/**
 * @brief   Performs a reset operation on the semaphore.
 * @post    After invoking this function all the threads waiting on the
 *          semaphore, if any, are released and the semaphore counter is set
 *          to the specified, non negative, value.
 * @note    The released threads can recognize they were waked up by a reset
 *          rather than a signal because the @p chSemWait() will return
 *          @p RDY_RESET instead of @p RDY_OK.
 *
 * @param[in] sp        pointer to a @p Semaphore structure
 * @param[in] n         the new value of the semaphore counter. The value must
 *                      be non-negative.
 *
 * @api
 */
void chSemReset(Semaphore *sp, cnt_t n) {

  chSysLock();
  chSemResetI(sp, n);
  chSchRescheduleS();
  chSysUnlock();
}

/**
 * @brief   Performs a reset operation on the semaphore.
 * @post    After invoking this function all the threads waiting on the
 *          semaphore, if any, are released and the semaphore counter is set
 *          to the specified, non negative, value.
 * @post    This function does not reschedule so a call to a rescheduling
 *          function must be performed before unlocking the kernel. Note that
 *          interrupt handlers always reschedule on exit so an explicit
 *          reschedule must not be performed in ISRs.
 * @note    The released threads can recognize they were waked up by a reset
 *          rather than a signal because the @p chSemWait() will return
 *          @p RDY_RESET instead of @p RDY_OK.
 *
 * @param[in] sp        pointer to a @p Semaphore structure
 * @param[in] n         the new value of the semaphore counter. The value must
 *                      be non-negative.
 *
 * @iclass
 */
void chSemResetI(Semaphore *sp, cnt_t n) {
  cnt_t cnt;

  chDbgCheckClassI();
  chDbgCheck((sp != NULL) && (n >= 0), "chSemResetI");
  chDbgAssert(((sp->s_cnt >= 0) && isempty(&sp->s_queue)) ||
              ((sp->s_cnt < 0) && notempty(&sp->s_queue)),
              "chSemResetI(), #1",
              "inconsistent semaphore");

  cnt = sp->s_cnt;
  sp->s_cnt = n;
  while (++cnt <= 0)
    chSchReadyI(lifo_remove(&sp->s_queue))->p_u.rdymsg = RDY_RESET;
}

/**
 * @brief   Performs a wait operation on a semaphore.
 *
 * @param[in] sp        pointer to a @p Semaphore structure
 * @return              A message specifying how the invoking thread has been
 *                      released from the semaphore.
 * @retval RDY_OK       if the thread has not stopped on the semaphore or the
 *                      semaphore has been signaled.
 * @retval RDY_RESET    if the semaphore has been reset using @p chSemReset().
 *
 * @api
 */
msg_t chSemWait(Semaphore *sp) {
  msg_t msg;

  chSysLock();
  msg = chSemWaitS(sp);
  chSysUnlock();
  return msg;
}

/**
 * @brief   Performs a wait operation on a semaphore.
 *
 * @param[in] sp        pointer to a @p Semaphore structure
 * @return              A message specifying how the invoking thread has been
 *                      released from the semaphore.
 * @retval RDY_OK       if the thread has not stopped on the semaphore or the
 *                      semaphore has been signaled.
 * @retval RDY_RESET    if the semaphore has been reset using @p chSemReset().
 *
 * @sclass
 */
msg_t chSemWaitS(Semaphore *sp) {

  chDbgCheckClassS();
  chDbgCheck(sp != NULL, "chSemWaitS");
  chDbgAssert(((sp->s_cnt >= 0) && isempty(&sp->s_queue)) ||
              ((sp->s_cnt < 0) && notempty(&sp->s_queue)),
              "chSemWaitS(), #1",
              "inconsistent semaphore");

  if (--sp->s_cnt < 0) {
    currp->p_u.wtobjp = sp;
    sem_insert(currp, &sp->s_queue);
    chSchGoSleepS(THD_STATE_WTSEM);
    return currp->p_u.rdymsg;
  }
  return RDY_OK;
}

/**
 * @brief   Performs a wait operation on a semaphore with timeout specification.
 *
 * @param[in] sp        pointer to a @p Semaphore structure
 * @param[in] time      the number of ticks before the operation timeouts,
 *                      the following special values are allowed:
 *                      - @a TIME_IMMEDIATE immediate timeout.
 *                      - @a TIME_INFINITE no timeout.
 *                      .
 * @return              A message specifying how the invoking thread has been
 *                      released from the semaphore.
 * @retval RDY_OK       if the thread has not stopped on the semaphore or the
 *                      semaphore has been signaled.
 * @retval RDY_RESET    if the semaphore has been reset using @p chSemReset().
 * @retval RDY_TIMEOUT  if the semaphore has not been signaled or reset within
 *                      the specified timeout.
 *
 * @api
 */
msg_t chSemWaitTimeout(Semaphore *sp, systime_t time) {
  msg_t msg;

  chSysLock();
  msg = chSemWaitTimeoutS(sp, time);
  chSysUnlock();
  return msg;
}

/**
 * @brief   Performs a wait operation on a semaphore with timeout specification.
 *
 * @param[in] sp        pointer to a @p Semaphore structure
 * @param[in] time      the number of ticks before the operation timeouts,
 *                      the following special values are allowed:
 *                      - @a TIME_IMMEDIATE immediate timeout.
 *                      - @a TIME_INFINITE no timeout.
 *                      .
 * @return              A message specifying how the invoking thread has been
 *                      released from the semaphore.
 * @retval RDY_OK       if the thread has not stopped on the semaphore or the
 *                      semaphore has been signaled.
 * @retval RDY_RESET    if the semaphore has been reset using @p chSemReset().
 * @retval RDY_TIMEOUT  if the semaphore has not been signaled or reset within
 *                      the specified timeout.
 *
 * @sclass
 */
msg_t chSemWaitTimeoutS(Semaphore *sp, systime_t time) {

  chDbgCheckClassS();
  chDbgCheck(sp != NULL, "chSemWaitTimeoutS");
  chDbgAssert(((sp->s_cnt >= 0) && isempty(&sp->s_queue)) ||
              ((sp->s_cnt < 0) && notempty(&sp->s_queue)),
              "chSemWaitTimeoutS(), #1",
              "inconsistent semaphore");

  if (--sp->s_cnt < 0) {
    if (TIME_IMMEDIATE == time) {
      sp->s_cnt++;
      return RDY_TIMEOUT;
    }
    currp->p_u.wtobjp = sp;
    sem_insert(currp, &sp->s_queue);
    return chSchGoSleepTimeoutS(THD_STATE_WTSEM, time);
  }
  return RDY_OK;
}

/**
 * @brief   Performs a signal operation on a semaphore.
 *
 * @param[in] sp        pointer to a @p Semaphore structure
 *
 * @api
 */
void chSemSignal(Semaphore *sp) {

  chDbgCheck(sp != NULL, "chSemSignal");
  chDbgAssert(((sp->s_cnt >= 0) && isempty(&sp->s_queue)) ||
              ((sp->s_cnt < 0) && notempty(&sp->s_queue)),
              "chSemSignal(), #1",
              "inconsistent semaphore");

  chSysLock();
  if (++sp->s_cnt <= 0)
    chSchWakeupS(fifo_remove(&sp->s_queue), RDY_OK);
  chSysUnlock();
}

/**
 * @brief   Performs a signal operation on a semaphore.
 * @post    This function does not reschedule so a call to a rescheduling
 *          function must be performed before unlocking the kernel. Note that
 *          interrupt handlers always reschedule on exit so an explicit
 *          reschedule must not be performed in ISRs.
 *
 * @param[in] sp    pointer to a @p Semaphore structure
 *
 * @iclass
 */
void chSemSignalI(Semaphore *sp) {

  chDbgCheckClassI();
  chDbgCheck(sp != NULL, "chSemSignalI");
  chDbgAssert(((sp->s_cnt >= 0) && isempty(&sp->s_queue)) ||
              ((sp->s_cnt < 0) && notempty(&sp->s_queue)),
              "chSemSignalI(), #1",
              "inconsistent semaphore");

  if (++sp->s_cnt <= 0) {
    /* Note, it is done this way in order to allow a tail call on
             chSchReadyI().*/
    Thread *tp = fifo_remove(&sp->s_queue);
    tp->p_u.rdymsg = RDY_OK;
    chSchReadyI(tp);
  }
}

/**
 * @brief   Adds the specified value to the semaphore counter.
 * @post    This function does not reschedule so a call to a rescheduling
 *          function must be performed before unlocking the kernel. Note that
 *          interrupt handlers always reschedule on exit so an explicit
 *          reschedule must not be performed in ISRs.
 *
 * @param[in] sp        pointer to a @p Semaphore structure
 * @param[in] n         value to be added to the semaphore counter. The value
 *                      must be positive.
 *
 * @iclass
 */
void chSemAddCounterI(Semaphore *sp, cnt_t n) {

  chDbgCheckClassI();
  chDbgCheck((sp != NULL) && (n > 0), "chSemAddCounterI");
  chDbgAssert(((sp->s_cnt >= 0) && isempty(&sp->s_queue)) ||
              ((sp->s_cnt < 0) && notempty(&sp->s_queue)),
              "chSemAddCounterI(), #1",
              "inconsistent semaphore");

  while (n > 0) {
    if (++sp->s_cnt <= 0)
      chSchReadyI(fifo_remove(&sp->s_queue))->p_u.rdymsg = RDY_OK;
    n--;
  }
}

#if CH_USE_SEMSW
/**
 * @brief   Performs atomic signal and wait operations on two semaphores.
 * @pre     The configuration option @p CH_USE_SEMSW must be enabled in order
 *          to use this function.
 *
 * @param[in] sps       pointer to a @p Semaphore structure to be signaled
 * @param[in] spw       pointer to a @p Semaphore structure to wait on
 * @return              A message specifying how the invoking thread has been
 *                      released from the semaphore.
 * @retval RDY_OK       if the thread has not stopped on the semaphore or the
 *                      semaphore has been signaled.
 * @retval RDY_RESET    if the semaphore has been reset using @p chSemReset().
 *
 * @api
 */
msg_t chSemSignalWait(Semaphore *sps, Semaphore *spw) {
  msg_t msg;

  chDbgCheck((sps != NULL) && (spw != NULL), "chSemSignalWait");
  chDbgAssert(((sps->s_cnt >= 0) && isempty(&sps->s_queue)) ||
              ((sps->s_cnt < 0) && notempty(&sps->s_queue)),
              "chSemSignalWait(), #1",
              "inconsistent semaphore");
  chDbgAssert(((spw->s_cnt >= 0) && isempty(&spw->s_queue)) ||
              ((spw->s_cnt < 0) && notempty(&spw->s_queue)),
              "chSemSignalWait(), #2",
              "inconsistent semaphore");

  chSysLock();
  if (++sps->s_cnt <= 0)
    chSchReadyI(fifo_remove(&sps->s_queue))->p_u.rdymsg = RDY_OK;
  if (--spw->s_cnt < 0) {
    Thread *ctp = currp;
    sem_insert(ctp, &spw->s_queue);
    ctp->p_u.wtobjp = spw;
    chSchGoSleepS(THD_STATE_WTSEM);
    msg = ctp->p_u.rdymsg;
  }
  else {
    chSchRescheduleS();
    msg = RDY_OK;
  }
  chSysUnlock();
  return msg;
}
#endif /* CH_USE_SEMSW */

#endif /* CH_USE_SEMAPHORES */

/** @} */