/*
    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    osal.h
 * @brief   OSAL module header.
 *
 * @addtogroup OSAL
 * @{
 */

#ifndef _OSAL_H_
#define _OSAL_H_

#include <stddef.h>
#include <stdint.h>
#include <stdbool.h>

#include "nil.h"

/*===========================================================================*/
/* Module constants.                                                         */
/*===========================================================================*/

/**
 * @name    Common constants
 * @{
 */
#if !defined(FALSE) || defined(__DOXYGEN__)
#define FALSE                               0
#endif

#if !defined(TRUE) || defined(__DOXYGEN__)
#define TRUE                                (!FALSE)
#endif

#define OSAL_SUCCESS                        FALSE
#define OSAL_FAILED                         TRUE
/** @} */

#if 0
/**
 * @name    Messages
 * @{
 */
#define MSG_OK                              RDY_OK
#define MSG_RESET                           RDY_RESET
#define MSG_TIMEOUT                         RDY_TIMEOUT
/** @} */
#endif

#if 0
/**
 * @name    Special time constants
 * @{
 */
#define TIME_IMMEDIATE                      ((systime_t)0)
#define TIME_INFINITE                       ((systime_t)-1)
/** @} */
#endif

/**
 * @name    Systick modes.
 * @{
 */
#define OSAL_ST_MODE_NONE                   0
#define OSAL_ST_MODE_PERIODIC               1
#define OSAL_ST_MODE_FREERUNNING            2
/** @} */

/**
 * @name    Systick parameters.
 * @{
 */
/**
 * @brief   Size in bits of the @p systick_t type.
 */
#define OSAL_ST_RESOLUTION                  NIL_CFG_ST_RESOLUTION

/**
 * @brief   Required systick frequency or resolution.
 */
#define OSAL_ST_FREQUENCY                   NIL_CFG_ST_FREQUENCY

/**
 * @brief   Systick mode required by the underlying OS.
 */
#if (NIL_CFG_ST_TIMEDELTA == 0) || defined(__DOXYGEN__)
#define OSAL_ST_MODE                        OSAL_ST_MODE_PERIODIC
#else
#define OSAL_ST_MODE                        OSAL_ST_MODE_FREERUNNING
#endif
/** @} */

/*===========================================================================*/
/* Module pre-compile time settings.                                         */
/*===========================================================================*/

/*===========================================================================*/
/* Derived constants and error checks.                                       */
/*===========================================================================*/

#if !NIL_CFG_USE_EVENTS
#error "OSAL requires NIL_CFG_USE_EVENTS=TRUE"
#endif

#if !(OSAL_ST_MODE == OSAL_ST_MODE_NONE) &&                                 \
    !(OSAL_ST_MODE == OSAL_ST_MODE_PERIODIC) &&                             \
    !(OSAL_ST_MODE == OSAL_ST_MODE_FREERUNNING)
#error "invalid OSAL_ST_MODE setting in osal.h"
#endif

#if (OSAL_ST_RESOLUTION != 16) && (OSAL_ST_RESOLUTION != 32)
#error "invalid OSAL_ST_RESOLUTION, must be 16 or 32"
#endif

/*===========================================================================*/
/* Module data structures and types.                                         */
/*===========================================================================*/

#if 0
/**
 * @brief   Type of a system status word.
 */
typedef uint32_t syssts_t;
#endif

#if 0
/**
 * @brief   Type of a message.
 */
typedef int32_t msg_t;
#endif

#if 0
/**
 * @brief   Type of system time counter.
 */
typedef uint32_t systime_t;
#endif

#if 0
/**
 * @brief   Type of realtime counter.
 */
typedef uint32_t rtcnt_t;
#endif

#if 0
/**
 * @brief   Type of a thread reference.
 */
typedef thread_t * thread_reference_t;
#endif

/**
 * @brief   Type of an event flags object.
 * @note    The content of this structure is not part of the API and should
 *          not be relied upon. Implementers may define this structure in
 *          an entirely different way.
 * @note    Retrieval and clearing of the flags are not defined in this
 *          API and are implementation-dependent.
 */
typedef struct event_source event_source_t;

/**
 * @brief   Type of an event source callback.
 * @note    This type is not part of the OSAL API and is provided
 *          exclusively as an example and for convenience.
 */
typedef void (*eventcallback_t)(event_source_t *);

/**
 * @brief   Type of an event flags mask.
 */
typedef uint32_t eventflags_t;

/**
 * @brief   Events source object.
 * @note    The content of this structure is not part of the API and should
 *          not be relied upon. Implementers may define this structure in
 *          an entirely different way.
 * @note    Retrieval and clearing of the flags are not defined in this
 *          API and are implementation-dependent.
 */
struct event_source {
  volatile eventflags_t flags;      /**< @brief Stored event flags.         */
  eventcallback_t       cb;         /**< @brief Event source callback.      */
  void                  *param;     /**< @brief User defined field.         */
};

/**
 * @brief   Type of a mutex.
 * @note    If the OS does not support mutexes or there is no OS then them
 *          mechanism can be simulated.
 */
typedef semaphore_t mutex_t;

/**
 * @brief   Type of a thread queue.
 * @details A thread queue is a queue of sleeping threads, queued threads
 *          can be dequeued one at time or all together.
 * @note    In this implementation it is implemented as a single reference
 *          because there are no real threads.
 */
typedef struct {
  semaphore_t   sem;
} threads_queue_t;

/*===========================================================================*/
/* Module macros.                                                            */
/*===========================================================================*/

/**
 * @name    Debug related macros
 * @{
 */
/**
 * @brief   Condition assertion.
 * @details If the condition check fails then the OSAL panics with a
 *          message and halts.
 * @note    The condition is tested only if the @p OSAL_ENABLE_ASSERTIONS
 *          switch is enabled.
 * @note    The convention for the message is the following:<br>
 *          @<function_name@>(), #@<assert_number@>
 * @note    The remark string is not currently used except for putting a
 *          comment in the code about the assertion.
 *
 * @param[in] c         the condition to be verified to be true
 * @param[in] remark    a remark string
 *
 * @api
 */
#define osalDbgAssert(c, remark) chDbgAssert(c, remark)

/**
 * @brief   Function parameters check.
 * @details If the condition check fails then the OSAL panics and halts.
 * @note    The condition is tested only if the @p OSAL_ENABLE_CHECKS switch
 *          is enabled.
 *
 * @param[in] c         the condition to be verified to be true
 *
 * @api
 */
#define osalDbgCheck(c) chDbgAssert(c, "parameter check")

/**
 * @brief   I-Class state check.
 * @note    Not implemented in this simplified OSAL.
 */
#define osalDbgCheckClassI() /*chDbgCheckClassI()*/
/** @} */

/**
 * @brief   S-Class state check.
 * @note    Not implemented in this simplified OSAL.
 */
#define osalDbgCheckClassS() /*chDbgCheckClassS()*/

/**
 * @name    IRQ service routines wrappers
 * @{
 */
/**
 * @brief   IRQ prologue code.
 * @details This macro must be inserted at the start of all IRQ handlers.
 */
#define OSAL_IRQ_PROLOGUE() CH_IRQ_PROLOGUE()

/**
 * @brief   IRQ epilogue code.
 * @details This macro must be inserted at the end of all IRQ handlers.
 */
#define OSAL_IRQ_EPILOGUE() CH_IRQ_EPILOGUE()

/**
 * @brief   IRQ handler function declaration.
 * @details This macro hides the details of an ISR function declaration.
 *
 * @param[in] id        a vector name as defined in @p vectors.s
 */
#define OSAL_IRQ_HANDLER(id) CH_IRQ_HANDLER(id)
/** @} */

/**
 * @name    Time conversion utilities
 * @{
 */
/**
 * @brief   Seconds to system ticks.
 * @details Converts from seconds to system ticks number.
 * @note    The result is rounded upward to the next tick boundary.
 *
 * @param[in] sec       number of seconds
 * @return              The number of ticks.
 *
 * @api
 */
#define OSAL_S2ST(sec) S2ST(sec)

/**
 * @brief   Milliseconds to system ticks.
 * @details Converts from milliseconds to system ticks number.
 * @note    The result is rounded upward to the next tick boundary.
 *
 * @param[in] msec      number of milliseconds
 * @return              The number of ticks.
 *
 * @api
 */
#define OSAL_MS2ST(msec) MS2ST(msec)
/**
 * @brief   Microseconds to system ticks.
 * @details Converts from microseconds to system ticks number.
 * @note    The result is rounded upward to the next tick boundary.
 *
 * @param[in] usec      number of microseconds
 * @return              The number of ticks.
 *
 * @api
 */
#define OSAL_US2ST(usec) US2ST(usec)
/** @} */

/*===========================================================================*/
/* External declarations.                                                    */
/*===========================================================================*/

#ifdef __cplusplus
extern "C" {
#endif
   void osalThreadDequeueNextI(threads_queue_t *tqp, msg_t msg);
   void osalThreadDequeueAllI(threads_queue_t *tqp, msg_t msg);
#ifdef __cplusplus
}
#endif

/*===========================================================================*/
/* Module inline functions.                                                  */
/*===========================================================================*/

/**
 * @brief   OSAL module initialization.
 *
 * @api
 */
static inline void osalInit(void) {

}

/**
 * @brief   System halt with error message.
 *
 * @param[in] reason    the halt message pointer
 *
 * @api
 */
static inline void osalSysHalt(const char *reason) {

  chSysHalt(reason);
}

/**
 * @brief   Enters a critical zone from thread context.
 * @note    This function cannot be used for reentrant critical zones.
 *
 * @special
 */
static inline void osalSysLock(void) {

  chSysLock();
}

/**
 * @brief   Leaves a critical zone from thread context.
 * @note    This function cannot be used for reentrant critical zones.
 *
 * @special
 */
static inline void osalSysUnlock(void) {

  chSysUnlock();
}

/**
 * @brief   Enters a critical zone from ISR context.
 * @note    This function cannot be used for reentrant critical zones.
 *
 * @special
 */
static inline void osalSysLockFromISR(void) {

  chSysLockFromISR();
}

/**
 * @brief   Leaves a critical zone from ISR context.
 * @note    This function cannot be used for reentrant critical zones.
 *
 * @special
 */
static inline void osalSysUnlockFromISR(void) {

  chSysUnlockFromISR();
}

/**
 * @brief   Returns the execution status and enters a critical zone.
 * @details This functions enters into a critical zone and can be called
 *          from any context. Because its flexibility it is less efficient
 *          than @p chSysLock() which is preferable when the calling context
 *          is known.
 * @post    The system is in a critical zone.
 *
 * @return              The previous system status, the encoding of this
 *                      status word is architecture-dependent and opaque.
 *
 * @xclass
 */
static inline syssts_t osalSysGetStatusAndLockX(void)  {

  return chSysGetStatusAndLockX();
}

/**
 * @brief   Restores the specified execution status and leaves a critical zone.
 * @note    A call to @p chSchRescheduleS() is automatically performed
 *          if exiting the critical zone and if not in ISR context.
 *
 * @param[in] sts       the system status to be restored.
 *
 * @xclass
 */
static inline void osalSysRestoreStatusX(syssts_t sts) {

  chSysRestoreStatusX(sts);
}

/**
 * @brief   Polled delay.
 * @note    The real delay is always few cycles in excess of the specified
 *          value.
 *
 * @param[in] cycles    number of cycles
 *
 * @xclass
 */
#if PORT_SUPPORTS_RT || defined(__DOXYGEN__)
static inline void osalSysPolledDelayX(rtcnt_t cycles) {

  chSysPolledDelayX(cycles);
}
#endif

/**
 * @brief   Systick callback for the underlying OS.
 * @note    This callback is only defined if the OSAL requires such a
 *          service from the HAL.
 */
#if (OSAL_ST_MODE != OSAL_ST_MODE_NONE) || defined(__DOXYGEN__)
static inline void osalOsTimerHandlerI(void) {

  chSysTimerHandlerI();
}
#endif

/**
 * @brief   Checks if a reschedule is required and performs it.
 * @note    I-Class functions invoked from thread context must not reschedule
 *          by themselves, an explicit reschedule using this function is
 *          required in this scenario.
 * @note    Not implemented in this simplified OSAL.
 *
 * @sclass
 */
static inline void osalOsRescheduleS(void) {

  chSchRescheduleS();
}

/**
 * @brief   Current system time.
 * @details Returns the number of system ticks since the @p chSysInit()
 *          invocation.
 * @note    The counter can reach its maximum and then restart from zero.
 * @note    This function can be called from any context but its atomicity
 *          is not guaranteed on architectures whose word size is less than
 *          @systime_t size.
 *
 * @return              The system time in ticks.
 *
 * @xclass
 */
static inline systime_t osalOsGetSystemTimeX(void) {

  return chVTGetSystemTimeX();
}

/**
 * @brief   Checks if the specified time is within the specified time window.
 * @note    When start==end then the function returns always true because the
 *          whole time range is specified.
 * @note    This function can be called from any context.
 *
 * @param[in] time      the time to be verified
 * @param[in] start     the start of the time window (inclusive)
 * @param[in] end       the end of the time window (non inclusive)
 * @retval true         current time within the specified time window.
 * @retval false        current time not within the specified time window.
 *
 * @xclass
 */
static inline bool osalOsIsTimeWithinX(systime_t time,
                                       systime_t start,
                                       systime_t end) {

  return chVTIsTimeWithinX(time, start, end);
}

/**
 * @brief   Suspends the invoking thread for the specified time.
 *
 * @param[in] time      the delay in system ticks, the special values are
 *                      handled as follow:
 *                      - @a TIME_INFINITE is allowed but interpreted as a
 *                        normal time specification.
 *                      - @a TIME_IMMEDIATE this value is not allowed.
 *                      .
 *
 * @sclass
 */
static inline void osalThreadSleepS(systime_t time) {

  chThdSleepS(time);
}

/**
 * @brief   Suspends the invoking thread for the specified time.
 *
 * @param[in] time      the delay in system ticks, the special values are
 *                      handled as follow:
 *                      - @a TIME_INFINITE is allowed but interpreted as a
 *                        normal time specification.
 *                      - @a TIME_IMMEDIATE this value is not allowed.
 *                      .
 *
 * @api
 */
static inline void osalThreadSleep(systime_t time) {

  chThdSleep(time);
}

/**
 * @brief   Sends the current thread sleeping and sets a reference variable.
 * @note    This function must reschedule, it can only be called from thread
 *          context.
 *
 * @param[in] trp       a pointer to a thread reference object
 * @return              The wake up message.
 *
 * @sclass
 */
static inline msg_t osalThreadSuspendS(thread_reference_t *trp) {

  return chThdSuspendTimeoutS(trp, TIME_INFINITE);
}

/**
 * @brief   Sends the current thread sleeping and sets a reference variable.
 * @note    This function must reschedule, it can only be called from thread
 *          context.
 *
 * @param[in] trp       a pointer to a thread reference object
 * @param[in] timeout   the timeout in system ticks, the special values are
 *                      handled as follow:
 *                      - @a TIME_INFINITE the thread enters an infinite sleep
 *                        state.
 *                      - @a TIME_IMMEDIATE the thread is not enqueued and
 *                        the function returns @p MSG_TIMEOUT as if a timeout
 *                        occurred.
 *                      .
 * @return              The wake up message.
 * @retval MSG_TIMEOUT  if the operation timed out.
 *
 * @sclass
 */
static inline msg_t osalThreadSuspendTimeoutS(thread_reference_t *trp,
                                              systime_t timeout) {

  return chThdSuspendTimeoutS(trp, timeout);
}

/**
 * @brief   Wakes up a thread waiting on a thread reference object.
 * @note    This function must not reschedule because it can be called from
 *          ISR context.
 *
 * @param[in] trp       a pointer to a thread reference object
 * @param[in] msg       the message code
 *
 * @iclass
 */
static inline void osalThreadResumeI(thread_reference_t *trp, msg_t msg) {

  chThdResumeI(trp, msg);
}

/**
 * @brief   Wakes up a thread waiting on a thread reference object.
 * @note    This function must reschedule, it can only be called from thread
 *          context.
 *
 * @param[in] trp       a pointer to a thread reference object
 * @param[in] msg       the message code
 *
 * @iclass
 */
static inline void osalThreadResumeS(thread_reference_t *trp, msg_t msg) {

  chThdResumeI(trp, msg);
  chSchRescheduleS();
}

/**
 * @brief   Initializes a threads queue object.
 *
 * @param[out] tqp      pointer to the threads queue object
 *
 * @init
 */
static inline void osalThreadQueueObjectInit(threads_queue_t *tqp) {

  chSemObjectInit(&tqp->sem, 0);
}

/**
 * @brief   Enqueues the caller thread.
 * @details The caller thread is enqueued and put to sleep until it is
 *          dequeued or the specified timeouts expires.
 *
 * @param[in] tqp       pointer to the threads queue object
 * @param[in] time      the timeout in system ticks, the special values are
 *                      handled as follow:
 *                      - @a TIME_INFINITE the thread enters an infinite sleep
 *                        state.
 *                      - @a TIME_IMMEDIATE the thread is not enqueued and
 *                        the function returns @p MSG_TIMEOUT as if a timeout
 *                        occurred.
 *                      .
 * @return              The message from @p osalQueueWakeupOneI() or
 *                      @p osalQueueWakeupAllI() functions.
 * @retval RDY_TIMEOUT  if the thread has not been dequeued within the
 *                      specified timeout or if the function has been
 *                      invoked with @p TIME_IMMEDIATE as timeout
 *                      specification.
 *
 * @sclass
 */
static inline msg_t osalThreadEnqueueTimeoutS(threads_queue_t *tqp,
                                              systime_t time) {

  return chSemWaitTimeout(&tqp->sem, time);
}

/**
 * @brief   Initializes an event flags object.
 *
 * @param[out] esp      pointer to the event flags object
 *
 * @init
 */
static inline void osalEventObjectInit(event_source_t *esp) {

  esp->flags = 0;
  esp->cb    = NULL;
  esp->param = NULL;
}

/**
 * @brief   Add flags to an event source object.
 *
 * @param[in] esp       pointer to the event flags object
 * @param[in] flags     flags to be ORed to the flags mask
 *
 * @iclass
 */
static inline void osalEventBroadcastFlagsI(event_source_t *esp,
                                            eventflags_t flags) {

  esp->flags |= flags;
  if (esp->cb != NULL)
    esp->cb(esp);
}

/**
 * @brief   Add flags to an event source object.
 *
 * @param[in] esp       pointer to the event flags object
 * @param[in] flags     flags to be ORed to the flags mask
 *
 * @iclass
 */
static inline void osalEventBroadcastFlags(event_source_t *esp,
                                           eventflags_t flags) {

  chSysLock();
  osalEventBroadcastFlagsI(esp, flags);
  chSchRescheduleS();
  chSysUnlock();
}

/**
 * @brief   Initializes s @p mutex_t object.
 *
 * @param[out] mp       pointer to the @p mutex_t object
 *
 * @init
 */
static inline void osalMutexObjectInit(mutex_t *mp) {

  chSemObjectInit((semaphore_t *)mp, 1);
}

/*
 * @brief   Locks the specified mutex.
 * @post    The mutex is locked and inserted in the per-thread stack of owned
 *          mutexes.
 *
 * @param[in,out] mp    pointer to the @p mutex_t object
 *
 * @api
 */
static inline void osalMutexLock(mutex_t *mp) {

  chSemWait((semaphore_t *)mp);
}

/**
 * @brief   Unlocks the specified mutex.
 * @note    The HAL guarantees to release mutex in reverse lock order. The
 *          mutex being unlocked is guaranteed to be the last locked mutex
 *          by the invoking thread.
 *          The implementation can rely on this behavior and eventually
 *          ignore the @p mp parameter which is supplied in order to support
 *          those OSes not supporting a stack of the owned mutexes.
 *
 * @param[in,out] mp    pointer to the @p mutex_t object
 *
 * @api
 */
static inline void osalMutexUnlock(mutex_t *mp) {

  chSemSignal((semaphore_t *)mp);
}

#endif /* _OSAL_H_ */

/** @} */