text: /*
   * Copyright (c) 2014, Mentor Graphics Corporation
   * Copyright (c) 2015 Xilinx, Inc.
   * Copyright (c) 2016 Freescale Semiconductor, Inc.
   * Copyright 2016 NXP
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions are met:
   *
   * 1. Redistributions of source code must retain the above copyright notice,
   *    this list of conditions and the following disclaimer.
   * 2. 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.
   * 3. Neither the name of the copyright holder 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 THE COPYRIGHT HOLDER OR 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.
   */
  
  #ifndef RPMSG_QUEUE_H_
  #define RPMSG_QUEUE_H_
  
  #include "rpmsg_lite.h"
  
  //! @addtogroup rpmsg_queue
  //! @{
  
  /*! \typedef rpmsg_queue_handle
      \brief Rpmsg queue handle type.
  */
  typedef void *rpmsg_queue_handle;
  
  /* RL_API_HAS_ZEROCOPY has to be enabled for RPMsg Queue to work */
  #if defined(RL_API_HAS_ZEROCOPY) && (RL_API_HAS_ZEROCOPY == 1)
  
  /*******************************************************************************
   * API
   ******************************************************************************/
  
  /* Exported API functions */
  
  #if defined(__cplusplus)
  extern "C" {
  #endif
  
  /*!
   * @brief
   * This callback needs to be registered with an endpoint
   *
   * @param payload Pointer to the buffer containing received data
   * @param payload_len Size of data received, in bytes
   * @param src Pointer to address of the endpoint from which data is received
   * @param priv Private data provided during endpoint creation
   *
   * @return RL_HOLD or RL_RELEASE to release or hold the buffer in payload
   */
  int32_t rpmsg_queue_rx_cb(void *payload, uint32_t payload_len, uint32_t src, void *priv);
  
  /*!
   * @brief
   * Create a RPMsg queue which can be used
   * for blocking reception.
   *
   * @param rpmsg_lite_dev    RPMsg Lite instance
   *
   * @return RPMsg queue handle or RL_NULL
   *
   */
  rpmsg_queue_handle rpmsg_queue_create(struct rpmsg_lite_instance *rpmsg_lite_dev);
  
  /*!
   * @brief
   * Destroy a queue and clean up.
   * Do not destroy a queue which is registered with an active endpoint!
   *
   * @param rpmsg_lite_dev    RPMsg-Lite instance
   * @param[in] q             RPMsg queue handle to destroy
   *
   * @return Status of function execution
   *
   */
  int32_t rpmsg_queue_destroy(struct rpmsg_lite_instance *rpmsg_lite_dev, rpmsg_queue_handle q);
  
  /*!
   * @brief
   * blocking receive function - blocking version of the received function that can be called from an RTOS task.
   * The data is copied from the receive buffer into the user supplied buffer.
   *
   * This is the "receive with copy" version of the RPMsg receive function. This version is simple
   * to use but it requires copying data from shared memory into the user space buffer.
   * The user has no obligation or burden to manage the shared memory buffers.
   *
   * @param rpmsg_lite_dev    RPMsg-Lite instance
   * @param[in] q             RPMsg queue handle to listen on
   * @param[in] data          Pointer to the user buffer the received data are copied to
   * @param[out] len          Pointer to an int variable that will contain the number of bytes actually copied into the
   * buffer
   * @param[in] maxlen        Maximum number of bytes to copy (received buffer size)
   * @param[out] src          Pointer to address of the endpoint from which data is received
   * @param[in] timeout       Timeout, in milliseconds, to wait for a message. A value of 0 means don't wait (non-blocking
   * call).
   *                          A value of 0xffffffff means wait forever (blocking call).
   *
   * @return Status of function execution
   *
   * @see rpmsg_queue_recv_nocopy
   */
  int32_t rpmsg_queue_recv(struct rpmsg_lite_instance *rpmsg_lite_dev,
                           rpmsg_queue_handle q,
                           uint32_t *src,
                           char *data,
                           uint32_t maxlen,
                           uint32_t *len,
                           uint32_t timeout);
  
  /*!
   * @brief
   * blocking receive function - blocking version of the received function that can be called from an RTOS task.
   * The data is NOT copied into the user-app. buffer.
   *
   * This is the "zero-copy receive" version of the RPMsg receive function. No data is copied.
   * Only the pointer to the data is returned. This version is fast, but it requires the user to manage
   * buffer allocation. Specifically, the user must decide when a buffer is no longer in use and
   * make the appropriate API call to free it, see rpmsg_queue_nocopy_free().
   *
   * @param rpmsg_lite_dev    RPMsg Lite instance
   * @param[in] q             RPMsg queue handle to listen on
   * @param[out] data         Pointer to the RPMsg buffer of the shared memory where the received data is stored
   * @param[out] len          Pointer to an int variable that that will contain the number of valid bytes in the RPMsg
   * buffer
   * @param[out] src          Pointer to address of the endpoint from which data is received
   * @param[in] timeout       Timeout, in milliseconds, to wait for a message. A value of 0 means don't wait (non-blocking
   * call).
   *                          A value of 0xffffffff means wait forever (blocking call).
   *
   * @return Status of function execution.
   *
   * @see rpmsg_queue_nocopy_free
   * @see rpmsg_queue_recv
   */
  int32_t rpmsg_queue_recv_nocopy(struct rpmsg_lite_instance *rpmsg_lite_dev,
                                  rpmsg_queue_handle q,
                                  uint32_t *src,
                                  char **data,
                                  uint32_t *len,
                                  uint32_t timeout);
  
  /*!
   * @brief This function frees a buffer previously returned by rpmsg_queue_recv_nocopy().
   *
   * Once the zero-copy mechanism of receiving data is used, this function
   * has to be called to free a buffer and to make it available for the next data
   * transfer.
   *
   * @param rpmsg_lite_dev    RPMsg-Lite instance
   * @param[in] data          Pointer to the RPMsg buffer of the shared memory that has to be freed
   *
   * @return Status of function execution.
   *
   * @see rpmsg_queue_recv_nocopy
   */
  int32_t rpmsg_queue_nocopy_free(struct rpmsg_lite_instance *rpmsg_lite_dev, void *data);
  
  /*!
   * @brief This function returns the number of pending messages in the queue.
   *
   * @param[in] q             RPMsg queue handle
   *
   * @return Number of pending messages in the queue.
   */
  int32_t rpmsg_queue_get_current_size(rpmsg_queue_handle q);
  
  //! @}
  
  #if defined(__cplusplus)
  }
  #endif
  
  #endif /* RL_API_HAS_ZEROCOPY */
  
  #endif /* RPMSG_QUEUE_H_ */
  