text: /*
   * Copyright (c) 2015, Freescale Semiconductor, Inc.
   * Copyright 2016-2017 NXP
   * All rights reserved.
   *
   * SPDX-License-Identifier: BSD-3-Clause
   */
  
  #include "fsl_uart_freertos.h"
  #include <FreeRTOS.h>
  #include <event_groups.h>
  #include <semphr.h>
  
  /* Component ID definition, used by tools. */
  #ifndef FSL_COMPONENT_ID
  #define FSL_COMPONENT_ID "platform.drivers.uart_freertos"
  #endif
  
  static void UART_RTOS_Callback(UART_Type *base, uart_handle_t *state, status_t status, void *param)
  {
      uart_rtos_handle_t *handle = (uart_rtos_handle_t *)param;
      BaseType_t xHigherPriorityTaskWoken, xResult;
  
      xHigherPriorityTaskWoken = pdFALSE;
      xResult                  = pdFAIL;
  
      if (status == kStatus_UART_RxIdle)
      {
          xResult = xEventGroupSetBitsFromISR(handle->rxEvent, RTOS_UART_COMPLETE, &xHigherPriorityTaskWoken);
      }
      if (status == kStatus_UART_TxIdle)
      {
          xResult = xEventGroupSetBitsFromISR(handle->txEvent, RTOS_UART_COMPLETE, &xHigherPriorityTaskWoken);
      }
      if (status == kStatus_UART_RxRingBufferOverrun)
      {
          xResult = xEventGroupSetBitsFromISR(handle->rxEvent, RTOS_UART_RING_BUFFER_OVERRUN, &xHigherPriorityTaskWoken);
      }
      if (status == kStatus_UART_RxHardwareOverrun)
      {
          /* Clear Overrun flag (OR) in UART S1 register */
          (void)UART_ClearStatusFlags(base, kUART_RxOverrunFlag);
          xResult =
              xEventGroupSetBitsFromISR(handle->rxEvent, RTOS_UART_HARDWARE_BUFFER_OVERRUN, &xHigherPriorityTaskWoken);
      }
      else
      {
          xResult = pdFAIL;
      }
  
      if (xResult != pdFAIL)
      {
          portYIELD_FROM_ISR(xHigherPriorityTaskWoken);
      }
  }
  
  /*FUNCTION**********************************************************************
   *
   * Function Name : UART_RTOS_Init
   * Description   : Initializes the UART instance for application
   *
   *END**************************************************************************/
  /*!
   * brief Initializes a UART instance for operation in RTOS.
   *
   * param handle The RTOS UART handle, the pointer to an allocated space for RTOS context.
   * param t_handle The pointer to the allocated space to store the transactional layer internal state.
   * param cfg The pointer to the parameters required to configure the UART after initialization.
   * return kStatus_Success, otherwise fail.
   */
  int UART_RTOS_Init(uart_rtos_handle_t *handle, uart_handle_t *t_handle, const uart_rtos_config_t *cfg)
  {
      status_t status;
      uart_config_t defcfg;
  
      if (NULL == handle)
      {
          return kStatus_InvalidArgument;
      }
      if (NULL == t_handle)
      {
          return kStatus_InvalidArgument;
      }
      if (NULL == cfg)
      {
          return kStatus_InvalidArgument;
      }
      if (NULL == cfg->base)
      {
          return kStatus_InvalidArgument;
      }
      if (0U == cfg->srcclk)
      {
          return kStatus_InvalidArgument;
      }
      if (0U == cfg->baudrate)
      {
          return kStatus_InvalidArgument;
      }
  
      handle->base    = cfg->base;
      handle->t_state = t_handle;
  #if (configSUPPORT_STATIC_ALLOCATION == 1)
      handle->txSemaphore = xSemaphoreCreateMutexStatic(&handle->txSemaphoreBuffer);
  #else
      handle->txSemaphore = xSemaphoreCreateMutex();
  #endif
      if (NULL == handle->txSemaphore)
      {
          return kStatus_Fail;
      }
  #if (configSUPPORT_STATIC_ALLOCATION == 1)
      handle->rxSemaphore = xSemaphoreCreateMutexStatic(&handle->rxSemaphoreBuffer);
  #else
      handle->rxSemaphore = xSemaphoreCreateMutex();
  #endif
      if (NULL == handle->rxSemaphore)
      {
          vSemaphoreDelete(handle->txSemaphore);
          return kStatus_Fail;
      }
  #if (configSUPPORT_STATIC_ALLOCATION == 1)
      handle->txEvent = xEventGroupCreateStatic(&handle->txEventBuffer);
  #else
      handle->txEvent     = xEventGroupCreate();
  #endif
      if (NULL == handle->txEvent)
      {
          vSemaphoreDelete(handle->rxSemaphore);
          vSemaphoreDelete(handle->txSemaphore);
          return kStatus_Fail;
      }
  #if (configSUPPORT_STATIC_ALLOCATION == 1)
      handle->rxEvent = xEventGroupCreateStatic(&handle->rxEventBuffer);
  #else
      handle->rxEvent     = xEventGroupCreate();
  #endif
      if (NULL == handle->rxEvent)
      {
          vEventGroupDelete(handle->txEvent);
          vSemaphoreDelete(handle->rxSemaphore);
          vSemaphoreDelete(handle->txSemaphore);
          return kStatus_Fail;
      }
      UART_GetDefaultConfig(&defcfg);
  
      defcfg.baudRate_Bps = cfg->baudrate;
      defcfg.parityMode   = cfg->parity;
  #if defined(FSL_FEATURE_UART_HAS_STOP_BIT_CONFIG_SUPPORT) && FSL_FEATURE_UART_HAS_STOP_BIT_CONFIG_SUPPORT
      defcfg.stopBitCount = cfg->stopbits;
  #endif
  
      status = UART_Init(handle->base, &defcfg, cfg->srcclk);
      if (status != kStatus_Success)
      {
          vEventGroupDelete(handle->rxEvent);
          vEventGroupDelete(handle->txEvent);
          vSemaphoreDelete(handle->rxSemaphore);
          vSemaphoreDelete(handle->txSemaphore);
          return kStatus_Fail;
      }
      UART_TransferCreateHandle(handle->base, handle->t_state, UART_RTOS_Callback, handle);
      UART_TransferStartRingBuffer(handle->base, handle->t_state, cfg->buffer, cfg->buffer_size);
  
      UART_EnableTx(handle->base, true);
      UART_EnableRx(handle->base, true);
  
      return kStatus_Success;
  }
  
  /*FUNCTION**********************************************************************
   *
   * Function Name : UART_RTOS_Deinit
   * Description   : Deinitializes the UART instance and frees resources
   *
   *END**************************************************************************/
  /*!
   * brief Deinitializes a UART instance for operation.
   *
   * This function deinitializes the UART module, sets all register values to reset value,
   * and frees the resources.
   *
   * param handle The RTOS UART handle.
   */
  int UART_RTOS_Deinit(uart_rtos_handle_t *handle)
  {
      UART_Deinit(handle->base);
  
      vEventGroupDelete(handle->txEvent);
      vEventGroupDelete(handle->rxEvent);
  
      /* Give the semaphore. This is for functional safety */
      (void)xSemaphoreGive(handle->txSemaphore);
      (void)xSemaphoreGive(handle->rxSemaphore);
  
      vSemaphoreDelete(handle->txSemaphore);
      vSemaphoreDelete(handle->rxSemaphore);
  
      /* Invalidate the handle */
      handle->base    = NULL;
      handle->t_state = NULL;
  
      return kStatus_Success;
  }
  
  /*FUNCTION**********************************************************************
   *
   * Function Name : UART_RTOS_Send
   * Description   : Initializes the UART instance for application
   *
   *END**************************************************************************/
  /*!
   * brief Sends data in the background.
   *
   * This function sends data. It is a synchronous API.
   * If the hardware buffer is full, the task is in the blocked state.
   *
   * param handle The RTOS UART handle.
   * param buffer The pointer to the buffer to send.
   * param length The number of bytes to send.
   */
  int UART_RTOS_Send(uart_rtos_handle_t *handle, uint8_t *buffer, uint32_t length)
  {
      EventBits_t ev;
      int retval = kStatus_Success;
      status_t status;
  
      if (NULL == handle->base)
      {
          /* Invalid handle. */
          return kStatus_Fail;
      }
      if (0U == length)
      {
          return kStatus_Success;
      }
      if (NULL == buffer)
      {
          return kStatus_InvalidArgument;
      }
  
      if (pdFALSE == xSemaphoreTake(handle->txSemaphore, 0))
      {
          /* We could not take the semaphore, exit with 0 data received */
          return kStatus_Fail;
      }
  
      handle->txTransfer.data     = (uint8_t *)buffer;
      handle->txTransfer.dataSize = (uint32_t)length;
  
      /* Non-blocking call */
      status = UART_TransferSendNonBlocking(handle->base, handle->t_state, &handle->txTransfer);
      if (status != kStatus_Success)
      {
          (void)xSemaphoreGive(handle->txSemaphore);
          return kStatus_Fail;
      }
  
      ev = xEventGroupWaitBits(handle->txEvent, RTOS_UART_COMPLETE, pdTRUE, pdFALSE, portMAX_DELAY);
      if ((ev & RTOS_UART_COMPLETE) == 0U)
      {
          retval = kStatus_Fail;
      }
  
      if (pdFALSE == xSemaphoreGive(handle->txSemaphore))
      {
          /* We could not post the semaphore, exit with error */
          retval = kStatus_Fail;
      }
  
      return retval;
  }
  
  /*FUNCTION**********************************************************************
   *
   * Function Name : UART_RTOS_Recv
   * Description   : Receives chars for the application
   *
   *END**************************************************************************/
  /*!
   * brief Receives data.
   *
   * This function receives data from UART. It is a synchronous API. If data is immediately available,
   * it is returned immediately and the number of bytes received.
   *
   * param handle The RTOS UART handle.
   * param buffer The pointer to the buffer to write received data.
   * param length The number of bytes to receive.
   * param received The pointer to a variable of size_t where the number of received data is filled.
   */
  int UART_RTOS_Receive(uart_rtos_handle_t *handle, uint8_t *buffer, uint32_t length, size_t *received)
  {
      EventBits_t ev;
      size_t n              = 0;
      int retval            = kStatus_Fail;
      size_t local_received = 0;
      status_t status;
  
      if (NULL == handle->base)
      {
          /* Invalid handle. */
          return kStatus_Fail;
      }
      if (0U == length)
      {
          if (received != NULL)
          {
              *received = n;
          }
          return kStatus_Success;
      }
      if (NULL == buffer)
      {
          return kStatus_InvalidArgument;
      }
  
      /* New transfer can be performed only after current one is finished */
      if (pdFALSE == xSemaphoreTake(handle->rxSemaphore, portMAX_DELAY))
      {
          /* We could not take the semaphore, exit with 0 data received */
          return kStatus_Fail;
      }
  
      handle->rxTransfer.data     = buffer;
      handle->rxTransfer.dataSize = (uint32_t)length;
  
      /* Non-blocking call */
      status = UART_TransferReceiveNonBlocking(handle->base, handle->t_state, &handle->rxTransfer, &n);
      if (status != kStatus_Success)
      {
          (void)xSemaphoreGive(handle->rxSemaphore);
          return kStatus_Fail;
      }
  
      ev = xEventGroupWaitBits(handle->rxEvent,
                               RTOS_UART_COMPLETE | RTOS_UART_RING_BUFFER_OVERRUN | RTOS_UART_HARDWARE_BUFFER_OVERRUN,
                               pdTRUE, pdFALSE, portMAX_DELAY);
      if ((ev & RTOS_UART_HARDWARE_BUFFER_OVERRUN) != 0U)
      {
          /* Stop data transfer to application buffer, ring buffer is still active */
          UART_TransferAbortReceive(handle->base, handle->t_state);
          /* Prevent false indication of successful transfer in next call of UART_RTOS_Receive.
             RTOS_UART_COMPLETE flag could be set meanwhile overrun is handled */
          (void)xEventGroupClearBits(handle->rxEvent, RTOS_UART_COMPLETE);
          retval         = kStatus_UART_RxHardwareOverrun;
          local_received = 0;
      }
      else if ((ev & RTOS_UART_RING_BUFFER_OVERRUN) != 0U)
      {
          /* Stop data transfer to application buffer, ring buffer is still active */
          UART_TransferAbortReceive(handle->base, handle->t_state);
          /* Prevent false indication of successful transfer in next call of UART_RTOS_Receive.
             RTOS_UART_COMPLETE flag could be set meanwhile overrun is handled */
          (void)xEventGroupClearBits(handle->rxEvent, RTOS_UART_COMPLETE);
          retval         = kStatus_UART_RxRingBufferOverrun;
          local_received = 0;
      }
      else if ((ev & RTOS_UART_COMPLETE) != 0U)
      {
          retval         = kStatus_Success;
          local_received = length;
      }
      else
      {
          retval         = kStatus_UART_Error;
          local_received = 0;
      }
  
      /* Prevent repetitive NULL check */
      if (received != NULL)
      {
          *received = local_received;
      }
  
      /* Enable next transfer. Current one is finished */
      if (pdFALSE == xSemaphoreGive(handle->rxSemaphore))
      {
          /* We could not post the semaphore, exit with error */
          retval = kStatus_Fail;
      }
      return retval;
  }
  