cmsis_os.c

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/* ----------------------------------------------------------------------
 * $Date:        5. February 2013
 * $Revision:    V1.02
 *
 * Project:      CMSIS-RTOS API
 * Title:        cmsis_os.c
 *
 * Version 0.02
 *    Initial Proposal Phase
 * Version 0.03
 *    osKernelStart added, optional feature: main started as thread
 *    osSemaphores have standard behavior
 *    osTimerCreate does not start the timer, added osTimerStart
 *    osThreadPass is renamed to osThreadYield
 * Version 1.01
 *    Support for C++ interface
 *     - const attribute removed from the osXxxxDef_t typedef's
 *     - const attribute added to the osXxxxDef macros
 *    Added: osTimerDelete, osMutexDelete, osSemaphoreDelete
 *    Added: osKernelInitialize
 * Version 1.02
 *    Control functions for short timeouts in microsecond resolution:
 *    Added: osKernelSysTick, osKernelSysTickFrequency, osKernelSysTickMicroSec
 *    Removed: osSignalGet 
 *    
 *  
 *----------------------------------------------------------------------------
 *
 * Portions Copyright © 2016 STMicroelectronics International N.V. All rights reserved.
 * Portions Copyright (c) 2013 ARM LIMITED
 * All rights reserved.
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *  - Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *  - Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *  - Neither the name of ARM  nor the names of its contributors may be used
 *    to endorse or promote products derived from this software without
 *    specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL COPYRIGHT HOLDERS AND CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *---------------------------------------------------------------------------*/

#include <string.h>
#include "cmsis_os.h"

extern void xPortSysTickHandler(void);

/* Convert from CMSIS type osPriority to FreeRTOS priority number */
static unsigned portBASE_TYPE makeFreeRtosPriority (osPriority priority)
{
  unsigned portBASE_TYPE fpriority = tskIDLE_PRIORITY;
  
  if (priority != osPriorityError) {
    fpriority += (priority - osPriorityIdle);
  }
  
  return fpriority;
}

#if (INCLUDE_uxTaskPriorityGet == 1)
/* Convert from FreeRTOS priority number to CMSIS type osPriority */
static osPriority makeCmsisPriority (unsigned portBASE_TYPE fpriority)
{
  osPriority priority = osPriorityError;
  
  if ((fpriority - tskIDLE_PRIORITY) <= (osPriorityRealtime - osPriorityIdle)) {
    priority = (osPriority)((int)osPriorityIdle + (int)(fpriority - tskIDLE_PRIORITY));
  }
  
  return priority;
}
#endif


/* Determine whether we are in thread mode or handler mode. */
static int inHandlerMode (void)
{
  return __get_IPSR() != 0;
}

/*********************** Kernel Control Functions *****************************/
osStatus osKernelInitialize (void);

osStatus osKernelStart (void)
{
  vTaskStartScheduler();
  
  return osOK;
}

int32_t osKernelRunning(void)
{
#if ( ( INCLUDE_xTaskGetSchedulerState == 1 ) || ( configUSE_TIMERS == 1 ) )
  if (xTaskGetSchedulerState() == taskSCHEDULER_NOT_STARTED)
    return 0;
  else
    return 1;
#else
    return (-1);
#endif  
}

#if (defined (osFeature_SysTick)  &&  (osFeature_SysTick != 0))     // System Timer available

uint32_t osKernelSysTick(void)
{
  if (inHandlerMode()) {
    return xTaskGetTickCountFromISR();
  }
  else {
    return xTaskGetTickCount();
  }
}
#endif    // System Timer available
/*********************** Thread Management *****************************/
osThreadId osThreadCreate (const osThreadDef_t *thread_def, void *argument)
{
  TaskHandle_t handle;
  
  
  if (xTaskCreate((TaskFunction_t)thread_def->pthread,(const portCHAR *)thread_def->name,
              thread_def->stacksize, argument, makeFreeRtosPriority(thread_def->tpriority),
              &handle) != pdPASS)  {
    return NULL;
  }
  
  return handle;
}

osThreadId osThreadGetId (void)
{
#if ( ( INCLUDE_xTaskGetCurrentTaskHandle == 1 ) || ( configUSE_MUTEXES == 1 ) )
  return xTaskGetCurrentTaskHandle();
#else
    return NULL;
#endif
}

osStatus osThreadTerminate (osThreadId thread_id)
{
#if (INCLUDE_vTaskDelete == 1)
  vTaskDelete(thread_id);
  return osOK;
#else
  return osErrorOS;
#endif
}

osStatus osThreadYield (void)
{
  taskYIELD();
  
  return osOK;
}

osStatus osThreadSetPriority (osThreadId thread_id, osPriority priority)
{
#if (INCLUDE_vTaskPrioritySet == 1)
  vTaskPrioritySet(thread_id, makeFreeRtosPriority(priority));
  return osOK;
#else
  return osErrorOS;
#endif
}

osPriority osThreadGetPriority (osThreadId thread_id)
{
#if (INCLUDE_uxTaskPriorityGet == 1)
  if (inHandlerMode())
  {
    return makeCmsisPriority(uxTaskPriorityGetFromISR(thread_id));  
  }
  else
  {  
    return makeCmsisPriority(uxTaskPriorityGet(thread_id));
  }
#else
  return osPriorityError;
#endif
}

/*********************** Generic Wait Functions *******************************/
osStatus osDelay (uint32_t millisec)
{
#if INCLUDE_vTaskDelay
  TickType_t ticks = millisec / portTICK_PERIOD_MS;
  
  vTaskDelay(ticks ? ticks : 1);          /* Minimum delay = 1 tick */
  
  return osOK;
#else
  (void) millisec;
  
  return osErrorResource;
#endif
}

#if (defined (osFeature_Wait)  &&  (osFeature_Wait != 0)) /* Generic Wait available */

osEvent osWait (uint32_t millisec);

#endif  /* Generic Wait available */

/***********************  Timer Management Functions ***************************/
osTimerId osTimerCreate (const osTimerDef_t *timer_def, os_timer_type type, void *argument)
{
#if (configUSE_TIMERS == 1)
  return xTimerCreate((const char *)"",
                      1, // period should be filled when starting the Timer using osTimerStart
                      (type == osTimerPeriodic) ? pdTRUE : pdFALSE,
                      (void *) argument,
                      (TaskFunction_t)timer_def->ptimer);
#else 
    return NULL;
#endif
}

osStatus osTimerStart (osTimerId timer_id, uint32_t millisec)
{
  osStatus result = osOK;
#if (configUSE_TIMERS == 1)  
  portBASE_TYPE taskWoken = pdFALSE;
  TickType_t ticks = millisec / portTICK_PERIOD_MS;

  if (ticks == 0)
    ticks = 1;
    
  if (inHandlerMode()) 
  {
    if (xTimerChangePeriodFromISR(timer_id, ticks, &taskWoken) != pdPASS)
    {
      result = osErrorOS;
    }
    else
    {
      portEND_SWITCHING_ISR(taskWoken);     
    }
  }
  else 
  {
    if (xTimerChangePeriod(timer_id, ticks, 0) != pdPASS)
      result = osErrorOS;
  }

#else 
  result = osErrorOS;
#endif
  return result;
}

osStatus osTimerStop (osTimerId timer_id)
{
  osStatus result = osOK;
#if (configUSE_TIMERS == 1)  
  portBASE_TYPE taskWoken = pdFALSE;

  if (inHandlerMode()) {
    if (xTimerStopFromISR(timer_id, &taskWoken) != pdPASS) {
      return osErrorOS;
    }
    portEND_SWITCHING_ISR(taskWoken);
  }
  else {
    if (xTimerStop(timer_id, 0) != pdPASS) {
      result = osErrorOS;
    }
  }
#else 
  result = osErrorOS;
#endif 
  return result;
}

osStatus osTimerDelete (osTimerId timer_id)
{
osStatus result = osOK;

#if (configUSE_TIMERS == 1)

   if (inHandlerMode()) {
     return osErrorISR;
  }
  else { 
    if ((xTimerDelete(timer_id, osWaitForever )) != pdPASS) {
      result = osErrorOS;
    }
  } 
    
#else 
  result = osErrorOS;
#endif 
 
  return result;
}

/***************************  Signal Management ********************************/
int32_t osSignalSet (osThreadId thread_id, int32_t signal)
{
#if( configUSE_TASK_NOTIFICATIONS == 1 )    
  BaseType_t xHigherPriorityTaskWoken = pdFALSE;
  
  if (inHandlerMode())
  {
    if(xTaskNotifyFromISR( thread_id, (uint32_t)signal, eSetBits, &xHigherPriorityTaskWoken ) != pdPASS )
      return osErrorOS;

    portYIELD_FROM_ISR( xHigherPriorityTaskWoken );
  }  
  else if(xTaskNotify( thread_id, (uint32_t)signal, eSetBits) != pdPASS )
  {
    return osErrorOS;
  }
  
  return osOK;
#else
  (void) thread_id;
  (void) signal;

  return osErrorOS; /* Task Notification not supported */   
#endif
}

int32_t osSignalClear (osThreadId thread_id, int32_t signal);

osEvent osSignalWait (int32_t signals, uint32_t millisec)
{
  osEvent ret;

#if( configUSE_TASK_NOTIFICATIONS == 1 )
    
  TickType_t ticks;

  ret.value.signals = 0;  
  ticks = 0;
  if (millisec == osWaitForever) {
    ticks = portMAX_DELAY;
  }
  else if (millisec != 0) {
    ticks = millisec / portTICK_PERIOD_MS;
    if (ticks == 0) {
      ticks = 1;
    }
  }  
  
  if (inHandlerMode())
  {
    ret.status = osErrorISR;  /*Not allowed in ISR*/
  }
  else
  {
    if(xTaskNotifyWait( 0,(uint32_t) signals, (uint32_t *)&ret.value.signals, ticks) != pdTRUE)
    {
      if(ticks == 0)  ret.status = osOK;
      else  ret.status = osEventTimeout;
    }
    else if(ret.value.signals < 0)
    {
      ret.status =  osErrorValue;     
    }
    else  ret.status =  osEventSignal;
  }
#else
  (void) signals;
  (void) millisec;
    
  ret.status =  osErrorOS;  /* Task Notification not supported */
#endif
  
  return ret;
}

/****************************  Mutex Management ********************************/
osMutexId osMutexCreate (const osMutexDef_t *mutex_def)
{
#if ( configUSE_MUTEXES == 1)
  return xSemaphoreCreateMutex(); 
#else
    return NULL;
#endif
}

osStatus osMutexWait (osMutexId mutex_id, uint32_t millisec)
{
  TickType_t ticks;
  portBASE_TYPE taskWoken = pdFALSE;  
  
  
  if (mutex_id == NULL) {
    return osErrorParameter;
  }
  
  ticks = 0;
  if (millisec == osWaitForever) {
    ticks = portMAX_DELAY;
  }
  else if (millisec != 0) {
    ticks = millisec / portTICK_PERIOD_MS;
    if (ticks == 0) {
      ticks = 1;
    }
  }
  
  if (inHandlerMode()) {
    if (xSemaphoreTakeFromISR(mutex_id, &taskWoken) != pdTRUE) {
      return osErrorOS;
    }
    portEND_SWITCHING_ISR(taskWoken);
  } 
  else if (xSemaphoreTake(mutex_id, ticks) != pdTRUE) {
    return osErrorOS;
  }
  
  return osOK;
}

osStatus osMutexRelease (osMutexId mutex_id)
{
  osStatus result = osOK;
  portBASE_TYPE taskWoken = pdFALSE;
  
  if (inHandlerMode()) {
    if (xSemaphoreGiveFromISR(mutex_id, &taskWoken) != pdTRUE) {
      return osErrorOS;
    }
    portEND_SWITCHING_ISR(taskWoken);
  }
  else if (xSemaphoreGive(mutex_id) != pdTRUE) 
  {
    result = osErrorOS;
  }
  return result;
}

osStatus osMutexDelete (osMutexId mutex_id)
{
  if (inHandlerMode()) {
    return osErrorISR;
  }

  vQueueDelete(mutex_id);

  return osOK;
}

/********************  Semaphore Management Functions **************************/

#if (defined (osFeature_Semaphore)  &&  (osFeature_Semaphore != 0))

osSemaphoreId osSemaphoreCreate (const osSemaphoreDef_t *semaphore_def, int32_t count)
{
  (void) semaphore_def;
  osSemaphoreId sema;
  
  if (count == 1) {
    vSemaphoreCreateBinary(sema);
    return sema;
  }

#if (configUSE_COUNTING_SEMAPHORES == 1 )   
  return xSemaphoreCreateCounting(count, 0);
#else
  return NULL;
#endif
}

int32_t osSemaphoreWait (osSemaphoreId semaphore_id, uint32_t millisec)
{
  TickType_t ticks;
  portBASE_TYPE taskWoken = pdFALSE;  
  
  
  if (semaphore_id == NULL) {
    return osErrorParameter;
  }
  
  ticks = 0;
  if (millisec == osWaitForever) {
    ticks = portMAX_DELAY;
  }
  else if (millisec != 0) {
    ticks = millisec / portTICK_PERIOD_MS;
    if (ticks == 0) {
      ticks = 1;
    }
  }
  
  if (inHandlerMode()) {
    if (xSemaphoreTakeFromISR(semaphore_id, &taskWoken) != pdTRUE) {
      return osErrorOS;
    }
    portEND_SWITCHING_ISR(taskWoken);
  }  
  else if (xSemaphoreTake(semaphore_id, ticks) != pdTRUE) {
    return osErrorOS;
  }
  
  return osOK;
}

osStatus osSemaphoreRelease (osSemaphoreId semaphore_id)
{
  osStatus result = osOK;
  portBASE_TYPE taskWoken = pdFALSE;
  
  
  if (inHandlerMode()) {
    if (xSemaphoreGiveFromISR(semaphore_id, &taskWoken) != pdTRUE) {
      return osErrorOS;
    }
    portEND_SWITCHING_ISR(taskWoken);
  }
  else {
    if (xSemaphoreGive(semaphore_id) != pdTRUE) {
      result = osErrorOS;
    }
  }
  
  return result;
}

osStatus osSemaphoreDelete (osSemaphoreId semaphore_id)
{
  if (inHandlerMode()) {
    return osErrorISR;
  }

  vSemaphoreDelete(semaphore_id);

  return osOK; 
}

#endif    /* Use Semaphores */

/*******************   Memory Pool Management Functions  ***********************/

#if (defined (osFeature_Pool)  &&  (osFeature_Pool != 0)) 

//TODO
//This is a primitive and inefficient wrapper around the existing FreeRTOS memory management.
//A better implementation will have to modify heap_x.c!


typedef struct os_pool_cb {
  void *pool;
  uint8_t *markers;
  uint32_t pool_sz;
  uint32_t item_sz;
  uint32_t currentIndex;
} os_pool_cb_t;


osPoolId osPoolCreate (const osPoolDef_t *pool_def)
{
  osPoolId thePool;
  int itemSize = 4 * ((pool_def->item_sz + 3) / 4);
  uint32_t i;
  
  /* First have to allocate memory for the pool control block. */
  thePool = pvPortMalloc(sizeof(os_pool_cb_t));
  if (thePool) {
    thePool->pool_sz = pool_def->pool_sz;
    thePool->item_sz = itemSize;
    thePool->currentIndex = 0;
    
    /* Memory for markers */
    thePool->markers = pvPortMalloc(pool_def->pool_sz);
    if (thePool->markers) {
      /* Now allocate the pool itself. */
      thePool->pool = pvPortMalloc(pool_def->pool_sz * itemSize);
      
      if (thePool->pool) {
        for (i = 0; i < pool_def->pool_sz; i++) {
          thePool->markers[i] = 0;
        }
      }
      else {
        vPortFree(thePool->markers);
        vPortFree(thePool);
        thePool = NULL;
      }
    }
    else {
      vPortFree(thePool);
      thePool = NULL;
    }
  }
  
  return thePool;
}

void *osPoolAlloc (osPoolId pool_id)
{
  int dummy = 0;
  void *p = NULL;
  uint32_t i;
  uint32_t index;
  
  if (inHandlerMode()) {
    dummy = portSET_INTERRUPT_MASK_FROM_ISR();
  }
  else {
    vPortEnterCritical();
  }
  
  for (i = 0; i < pool_id->pool_sz; i++) {
    index = pool_id->currentIndex + i;
    if (index >= pool_id->pool_sz) {
      index = 0;
    }
    
    if (pool_id->markers[index] == 0) {
      pool_id->markers[index] = 1;
      p = (void *)((uint32_t)(pool_id->pool) + (index * pool_id->item_sz));
      pool_id->currentIndex = index;
      break;
    }
  }
  
  if (inHandlerMode()) {
    portCLEAR_INTERRUPT_MASK_FROM_ISR(dummy);
  }
  else {
    vPortExitCritical();
  }
  
  return p;
}

void *osPoolCAlloc (osPoolId pool_id)
{
  void *p = osPoolAlloc(pool_id);
  
  if (p != NULL)
  {
    memset(p, 0, sizeof(pool_id->pool_sz));
  }
  
  return p;
}

osStatus osPoolFree (osPoolId pool_id, void *block)
{
  uint32_t index;
  
  if (pool_id == NULL) {
    return osErrorParameter;
  }
  
  if (block == NULL) {
    return osErrorParameter;
  }
  
  if (block < pool_id->pool) {
    return osErrorParameter;
  }
  
  index = (uint32_t)block - (uint32_t)(pool_id->pool);
  if (index % pool_id->item_sz) {
    return osErrorParameter;
  }
  index = index / pool_id->item_sz;
  if (index >= pool_id->pool_sz) {
    return osErrorParameter;
  }
  
  pool_id->markers[index] = 0;
  
  return osOK;
}


#endif   /* Use Memory Pool Management */

/*******************   Message Queue Management Functions  *********************/

#if (defined (osFeature_MessageQ)  &&  (osFeature_MessageQ != 0)) /* Use Message Queues */

osMessageQId osMessageCreate (const osMessageQDef_t *queue_def, osThreadId thread_id)
{
  (void) thread_id;
  
  return xQueueCreate(queue_def->queue_sz, queue_def->item_sz);
}

osStatus osMessagePut (osMessageQId queue_id, uint32_t info, uint32_t millisec)
{
  portBASE_TYPE taskWoken = pdFALSE;
  TickType_t ticks;
  
  ticks = millisec / portTICK_PERIOD_MS;
  if (ticks == 0) {
    ticks = 1;
  }
  
  if (inHandlerMode()) {
    if (xQueueSendFromISR(queue_id, &info, &taskWoken) != pdTRUE) {
      return osErrorOS;
    }
    portEND_SWITCHING_ISR(taskWoken);
  }
  else {
    if (xQueueSend(queue_id, &info, ticks) != pdTRUE) {
      return osErrorOS;
    }
  }
  
  return osOK;
}

osEvent osMessageGet (osMessageQId queue_id, uint32_t millisec)
{
  portBASE_TYPE taskWoken;
  TickType_t ticks;
  osEvent event;
  
  event.def.message_id = queue_id;
  event.value.v = 0;
  
  if (queue_id == NULL) {
    event.status = osErrorParameter;
    return event;
  }
  
  taskWoken = pdFALSE;
  
  ticks = 0;
  if (millisec == osWaitForever) {
    ticks = portMAX_DELAY;
  }
  else if (millisec != 0) {
    ticks = millisec / portTICK_PERIOD_MS;
    if (ticks == 0) {
      ticks = 1;
    }
  }
  
  if (inHandlerMode()) {
    if (xQueueReceiveFromISR(queue_id, &event.value.v, &taskWoken) == pdTRUE) {
      /* We have mail */
      event.status = osEventMessage;
    }
    else {
      event.status = osOK;
    }
    portEND_SWITCHING_ISR(taskWoken);
  }
  else {
    if (xQueueReceive(queue_id, &event.value.v, ticks) == pdTRUE) {
      /* We have mail */
      event.status = osEventMessage;
    }
    else {
      event.status = (ticks == 0) ? osOK : osEventTimeout;
    }
  }
  
  return event;
}

#endif     /* Use Message Queues */

/********************   Mail Queue Management Functions  ***********************/
#if (defined (osFeature_MailQ)  &&  (osFeature_MailQ != 0))  /* Use Mail Queues */


typedef struct os_mailQ_cb {
  const osMailQDef_t *queue_def;
  QueueHandle_t handle;
  osPoolId pool;
} os_mailQ_cb_t;

osMailQId osMailCreate (const osMailQDef_t *queue_def, osThreadId thread_id)
{
  (void) thread_id;
  
  osPoolDef_t pool_def = {queue_def->queue_sz, queue_def->item_sz, NULL};
  
  
  /* Create a mail queue control block */
  *(queue_def->cb) = pvPortMalloc(sizeof(struct os_mailQ_cb));
  if (*(queue_def->cb) == NULL) {
    return NULL;
  }
  (*(queue_def->cb))->queue_def = queue_def;
  
  /* Create a queue in FreeRTOS */
  (*(queue_def->cb))->handle = xQueueCreate(queue_def->queue_sz, sizeof(void *));
  if ((*(queue_def->cb))->handle == NULL) {
    vPortFree(*(queue_def->cb));
    return NULL;
  }
  
  /* Create a mail pool */
  (*(queue_def->cb))->pool = osPoolCreate(&pool_def);
  if ((*(queue_def->cb))->pool == NULL) {
    //TODO: Delete queue. How to do it in FreeRTOS?
    vPortFree(*(queue_def->cb));
    return NULL;
  }
  
  return *(queue_def->cb);
}

void *osMailAlloc (osMailQId queue_id, uint32_t millisec)
{
  (void) millisec;
  void *p;
  
  
  if (queue_id == NULL) {
    return NULL;
  }
  
  p = osPoolAlloc(queue_id->pool);
  
  return p;
}

void *osMailCAlloc (osMailQId queue_id, uint32_t millisec)
{
  uint32_t i;
  void *p = osMailAlloc(queue_id, millisec);
  
  if (p) {
    for (i = 0; i < sizeof(queue_id->queue_def->item_sz); i++) {
      ((uint8_t *)p)[i] = 0;
    }
  }
  
  return p;
}

osStatus osMailPut (osMailQId queue_id, void *mail)
{
  portBASE_TYPE taskWoken;
  
  
  if (queue_id == NULL) {
    return osErrorParameter;
  }
  
  taskWoken = pdFALSE;
  
  if (inHandlerMode()) {
    if (xQueueSendFromISR(queue_id->handle, &mail, &taskWoken) != pdTRUE) {
      return osErrorOS;
    }
    portEND_SWITCHING_ISR(taskWoken);
  }
  else {
    if (xQueueSend(queue_id->handle, &mail, 0) != pdTRUE) { 
      return osErrorOS;
    }
  }
  
  return osOK;
}

osEvent osMailGet (osMailQId queue_id, uint32_t millisec)
{
  portBASE_TYPE taskWoken;
  TickType_t ticks;
  osEvent event;
  
  event.def.mail_id = queue_id;
  
  if (queue_id == NULL) {
    event.status = osErrorParameter;
    return event;
  }
  
  taskWoken = pdFALSE;
  
  ticks = 0;
  if (millisec == osWaitForever) {
    ticks = portMAX_DELAY;
  }
  else if (millisec != 0) {
    ticks = millisec / portTICK_PERIOD_MS;
    if (ticks == 0) {
      ticks = 1;
    }
  }
  
  if (inHandlerMode()) {
    if (xQueueReceiveFromISR(queue_id->handle, &event.value.p, &taskWoken) == pdTRUE) {
      /* We have mail */
      event.status = osEventMail;
    }
    else {
      event.status = osOK;
    }
    portEND_SWITCHING_ISR(taskWoken);
  }
  else {
    if (xQueueReceive(queue_id->handle, &event.value.p, ticks) == pdTRUE) {
      /* We have mail */
      event.status = osEventMail;
    }
    else {
      event.status = (ticks == 0) ? osOK : osEventTimeout;
    }
  }
  
  return event;
}

osStatus osMailFree (osMailQId queue_id, void *mail)
{
  if (queue_id == NULL) {
    return osErrorParameter;
  }
  
  return osPoolFree(queue_id->pool, mail);
}
#endif  /* Use Mail Queues */

/*************************** Additional specific APIs to Free RTOS ************/
void osSystickHandler(void)
{

#if (INCLUDE_xTaskGetSchedulerState  == 1 )
  if (xTaskGetSchedulerState() != taskSCHEDULER_NOT_STARTED)
  {
#endif  /* INCLUDE_xTaskGetSchedulerState */  
    xPortSysTickHandler();
#if (INCLUDE_xTaskGetSchedulerState  == 1 )
  }
#endif  /* INCLUDE_xTaskGetSchedulerState */  
}

#if ( INCLUDE_eTaskGetState == 1 )

osThreadState osThreadGetState(osThreadId thread_id)
{
  eTaskState ThreadState;
  osThreadState result;
  
  ThreadState = eTaskGetState(thread_id);
  
  switch (ThreadState)
  {
  case eRunning :
    result = osThreadRunning;
    break;
  case eReady :
    result = osThreadReady;
    break;
  case eBlocked :
    result = osThreadBlocked;
    break;
  case eSuspended :
    result = osThreadSuspended;
    break;
  case eDeleted :
    result = osThreadDeleted;
    break;
  default:
    result = osThreadError;
  } 
  
  return result;
}
#endif /* INCLUDE_eTaskGetState */

#if (INCLUDE_eTaskGetState == 1)

osStatus osThreadIsSuspended(osThreadId thread_id)
{
  if (eTaskGetState(thread_id) == eSuspended)
    return osOK;
  else
    return osErrorOS;
}
#endif /* INCLUDE_eTaskGetState */

osStatus osThreadSuspend (osThreadId thread_id)
{
#if (INCLUDE_vTaskSuspend == 1)
    vTaskSuspend(thread_id);
  
  return osOK;
#else
  return osErrorResource;
#endif
}

osStatus osThreadResume (osThreadId thread_id)
{
#if (INCLUDE_vTaskSuspend == 1)  
  if(inHandlerMode())
  {
    if (xTaskResumeFromISR(thread_id) == pdTRUE)
    {
      portYIELD_FROM_ISR(pdTRUE);
    }
  }
  else
  {
    vTaskResume(thread_id);
  }
  return osOK;
#else
  return osErrorResource;
#endif
}

osStatus osThreadSuspendAll (void)
{
  vTaskSuspendAll();
  
  return osOK;
}

osStatus osThreadResumeAll (void)
{
  if (xTaskResumeAll() == pdTRUE)
    return osOK;
  else
    return osErrorOS;
  
}

osStatus osDelayUntil (uint32_t *PreviousWakeTime, uint32_t millisec)
{
#if INCLUDE_vTaskDelayUntil
  TickType_t ticks = (millisec / portTICK_PERIOD_MS);
  vTaskDelayUntil((TickType_t *) PreviousWakeTime, ticks ? ticks : 1);
  
  return osOK;
#else
  (void) millisec;
  (void) PreviousWakeTime;
  
  return osErrorResource;
#endif
}

osStatus osThreadList (uint8_t *buffer)
{
#if ( ( configUSE_TRACE_FACILITY == 1 ) && ( configUSE_STATS_FORMATTING_FUNCTIONS == 1 ) )
  vTaskList((char *)buffer);
#endif
  return osOK;
}

osEvent osMessagePeek (osMessageQId queue_id, uint32_t millisec)
{
  TickType_t ticks;
  osEvent event;
  
  event.def.message_id = queue_id;
  
  if (queue_id == NULL) {
    event.status = osErrorParameter;
    return event;
  }
  
  ticks = 0;
  if (millisec == osWaitForever) {
    ticks = portMAX_DELAY;
  }
  else if (millisec != 0) {
    ticks = millisec / portTICK_PERIOD_MS;
    if (ticks == 0) {
      ticks = 1;
    }
  }
  
  if (xQueuePeek(queue_id, &event.value.v, ticks) == pdTRUE) 
  {
    /* We have mail */
    event.status = osEventMessage;
  }
  else 
  {
    event.status = (ticks == 0) ? osOK : osEventTimeout;
  }
  
  return event;
}

osMutexId osRecursiveMutexCreate (const osMutexDef_t *mutex_def)
{
  (void) mutex_def;
#if (configUSE_RECURSIVE_MUTEXES == 1)
  return xSemaphoreCreateRecursiveMutex();
#else
  return NULL;
#endif  
}

osStatus osRecursiveMutexRelease (osMutexId mutex_id)
{
#if (configUSE_RECURSIVE_MUTEXES == 1)
  osStatus result = osOK;
 
  if (xSemaphoreGiveRecursive(mutex_id) != pdTRUE) 
  {
    result = osErrorOS;
  }
  return result;
#else
    return osErrorResource;
#endif
}

osStatus osRecursiveMutexWait (osMutexId mutex_id, uint32_t millisec)
{
#if (configUSE_RECURSIVE_MUTEXES == 1)
  TickType_t ticks;
  
  if (mutex_id == NULL)
  {
    return osErrorParameter;
  }
  
  ticks = 0;
  if (millisec == osWaitForever) 
  {
    ticks = portMAX_DELAY;
  }
  else if (millisec != 0) 
  {
    ticks = millisec / portTICK_PERIOD_MS;
    if (ticks == 0) 
    {
      ticks = 1;
    }
  }
  
  if (xSemaphoreTakeRecursive(mutex_id, ticks) != pdTRUE) 
  {
    return osErrorOS;
  }
  return osOK;
#else
    return osErrorResource;
#endif
}