text: /**
   * \file
   *
   * \brief I/O USART related functionality implementation.
   *
   * Copyright (C) 2014 - 2016 Atmel Corporation. All rights reserved.
   *
   * \asf_license_start
   *
   * \page License
   *
   * 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. The name of Atmel may not be used to endorse or promote products derived
   *    from this software without specific prior written permission.
   *
   * 4. This software may only be redistributed and used in connection with an
   *    Atmel microcontroller product.
   *
   * THIS SOFTWARE IS PROVIDED BY ATMEL "AS IS" AND ANY EXPRESS OR IMPLIED
   * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
   * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT ARE
   * EXPRESSLY AND SPECIFICALLY DISCLAIMED. IN NO EVENT SHALL ATMEL 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.
   *
   * \asf_license_stop
   *
   */
  
  #include "hal_usart_async.h"
  #include <utils_assert.h>
  #include <hal_atomic.h>
  #include <utils.h>
  
  /**
   * \brief Driver version
   */
  #define DRIVER_VERSION 0x00000001u
  
  static int32_t usart_async_write(struct io_descriptor *const io_descr, const uint8_t *const buf, const uint16_t length);
  static int32_t usart_async_read(struct io_descriptor *const io_descr, uint8_t *const buf, const uint16_t length);
  static void usart_process_byte_sent(struct _usart_async_device *device);
  static void usart_transmission_complete(struct _usart_async_device *device);
  static void usart_error(struct _usart_async_device *device);
  static void usart_fill_rx_buffer(struct _usart_async_device *device, uint8_t data);
  
  /**
   * \brief Initialize usart interface
   */
  int32_t usart_async_init(struct usart_async_descriptor *const descr, void *const hw, uint8_t *rx_buffer,
                           uint16_t rx_buffer_length, void *const func)
  {
  	int32_t init_status;
  	ASSERT(descr && hw && rx_buffer && rx_buffer_length);
  
  	if (ERR_NONE != ringbuffer_init(&descr->rx, rx_buffer, rx_buffer_length)) {
  		return ERR_INVALID_ARG;
  	}
  	init_status = _usart_async_init(&descr->device, hw);
  	if (init_status) {
  		return init_status;
  	}
  
  	descr->io.read  = usart_async_read;
  	descr->io.write = usart_async_write;
  
  	descr->device.usart_cb.tx_byte_sent = usart_process_byte_sent;
  	descr->device.usart_cb.rx_done_cb   = usart_fill_rx_buffer;
  	descr->device.usart_cb.tx_done_cb   = usart_transmission_complete;
  	descr->device.usart_cb.error_cb     = usart_error;
  
  	return ERR_NONE;
  }
  
  /**
   * \brief Deinitialize usart interface
   */
  int32_t usart_async_deinit(struct usart_async_descriptor *const descr)
  {
  	ASSERT(descr);
  	_usart_async_deinit(&descr->device);
  	descr->io.read  = NULL;
  	descr->io.write = NULL;
  
  	return ERR_NONE;
  }
  
  /**
   * \brief Enable usart interface
   */
  int32_t usart_async_enable(struct usart_async_descriptor *const descr)
  {
  	ASSERT(descr);
  	_usart_async_enable(&descr->device);
  
  	return ERR_NONE;
  }
  
  /**
   * \brief Disable usart interface
   */
  int32_t usart_async_disable(struct usart_async_descriptor *const descr)
  {
  	ASSERT(descr);
  	_usart_async_disable(&descr->device);
  
  	return ERR_NONE;
  }
  
  /**
   * \brief Retrieve I/O descriptor
   */
  int32_t usart_async_get_io_descriptor(struct usart_async_descriptor *const descr, struct io_descriptor **io)
  {
  	ASSERT(descr && io);
  
  	*io = &descr->io;
  	return ERR_NONE;
  }
  
  /**
   * \brief Register usart callback
   */
  int32_t usart_async_register_callback(struct usart_async_descriptor *const descr,
                                        const enum usart_async_callback_type type, usart_cb_t cb)
  {
  	ASSERT(descr);
  
  	switch (type) {
  	case USART_ASYNC_RXC_CB:
  		descr->usart_cb.rx_done = cb;
  		_usart_async_set_irq_state(&descr->device, USART_ASYNC_RX_DONE, NULL != cb);
  		break;
  	case USART_ASYNC_TXC_CB:
  		descr->usart_cb.tx_done = cb;
  		_usart_async_set_irq_state(&descr->device, USART_ASYNC_TX_DONE, NULL != cb);
  		break;
  	case USART_ASYNC_ERROR_CB:
  		descr->usart_cb.error = cb;
  		_usart_async_set_irq_state(&descr->device, USART_ASYNC_ERROR, NULL != cb);
  		break;
  	default:
  		return ERR_INVALID_ARG;
  	}
  
  	return ERR_NONE;
  }
  
  /**
   * \brief Specify action for flow control pins
   */
  int32_t usart_async_set_flow_control(struct usart_async_descriptor *const descr,
                                       const union usart_flow_control_state state)
  {
  	ASSERT(descr);
  	_usart_async_set_flow_control_state(&descr->device, state);
  
  	return ERR_NONE;
  }
  
  /**
   * \brief Set usart baud rate
   */
  int32_t usart_async_set_baud_rate(struct usart_async_descriptor *const descr, const uint32_t baud_rate)
  {
  	ASSERT(descr);
  	_usart_async_set_baud_rate(&descr->device, baud_rate);
  
  	return ERR_NONE;
  }
  
  /**
   * \brief Set usart data order
   */
  int32_t usart_async_set_data_order(struct usart_async_descriptor *const descr, const enum usart_data_order data_order)
  {
  	ASSERT(descr);
  	_usart_async_set_data_order(&descr->device, data_order);
  
  	return ERR_NONE;
  }
  
  /**
   * \brief Set usart mode
   */
  int32_t usart_async_set_mode(struct usart_async_descriptor *const descr, const enum usart_mode mode)
  {
  	ASSERT(descr);
  	_usart_async_set_mode(&descr->device, mode);
  
  	return ERR_NONE;
  }
  
  /**
   * \brief Set usart parity
   */
  int32_t usart_async_set_parity(struct usart_async_descriptor *const descr, const enum usart_parity parity)
  {
  	ASSERT(descr);
  	_usart_async_set_parity(&descr->device, parity);
  
  	return ERR_NONE;
  }
  
  /**
   * \brief Set usart stop bits
   */
  int32_t usart_async_set_stopbits(struct usart_async_descriptor *const descr, const enum usart_stop_bits stop_bits)
  {
  	ASSERT(descr);
  	_usart_async_set_stop_bits(&descr->device, stop_bits);
  
  	return ERR_NONE;
  }
  
  /**
   * \brief Set usart character size
   */
  int32_t usart_async_set_character_size(struct usart_async_descriptor *const descr, const enum usart_character_size size)
  {
  	ASSERT(descr);
  	_usart_async_set_character_size(&descr->device, size);
  
  	return ERR_NONE;
  }
  
  /**
   * \brief Retrieve the state of flow control pins
   */
  int32_t usart_async_flow_control_status(const struct usart_async_descriptor *const descr,
                                          union usart_flow_control_state *const      state)
  {
  	ASSERT(descr && state);
  	*state = _usart_async_get_flow_control_state(&descr->device);
  
  	return ERR_NONE;
  }
  
  /**
   * \brief Check if the usart transmitter is empty
   */
  int32_t usart_async_is_tx_empty(const struct usart_async_descriptor *const descr)
  {
  	ASSERT(descr);
  	return _usart_async_is_byte_sent(&descr->device);
  }
  
  /**
   * \brief Check if the usart receiver is not empty
   */
  int32_t usart_async_is_rx_not_empty(const struct usart_async_descriptor *const descr)
  {
  	ASSERT(descr);
  
  	return ringbuffer_num(&descr->rx) > 0;
  }
  
  /**
   * \brief Retrieve the current interface status
   */
  int32_t usart_async_get_status(struct usart_async_descriptor *const descr, struct usart_async_status *const status)
  {
  	ASSERT(descr);
  
  	volatile uint32_t *tmp_stat  = &(descr->stat);
  	volatile uint16_t *tmp_txcnt = &(descr->tx_por);
  
  	if (status) {
  		status->flags = *tmp_stat;
  		status->txcnt = *tmp_txcnt;
  		status->rxcnt = ringbuffer_num(&descr->rx);
  	}
  	if (*tmp_stat & USART_ASYNC_STATUS_BUSY) {
  		return ERR_BUSY;
  	}
  
  	return ERR_NONE;
  }
  
  /**
   * \brief flush usart rx ringbuf
   */
  int32_t usart_async_flush_rx_buffer(struct usart_async_descriptor *const descr)
  {
  	ASSERT(descr);
  
  	return ringbuffer_flush(&descr->rx);
  }
  
  /**
   * \brief Retrieve the current driver version
   */
  uint32_t usart_async_get_version(void)
  {
  	return DRIVER_VERSION;
  }
  
  /*
   * \internal Write the given data to usart interface
   *
   * \param[in] descr The pointer to an io descriptor
   * \param[in] buf Data to write to usart
   * \param[in] length The number of bytes to write
   *
   * \return The number of bytes written.
   */
  static int32_t usart_async_write(struct io_descriptor *const io_descr, const uint8_t *const buf, const uint16_t length)
  {
  	#pragma GCC diagnostic push
  	#pragma GCC diagnostic ignored "-Wcast-align"
  	struct usart_async_descriptor *descr = CONTAINER_OF(io_descr, struct usart_async_descriptor, io);
  	#pragma GCC diagnostic pop
  
  	ASSERT(descr && buf && length);
  
  	if (descr->tx_por != descr->tx_buffer_length) {
  		return ERR_NO_RESOURCE;
  	}
  	descr->tx_buffer        = (uint8_t *)buf;
  	descr->tx_buffer_length = length;
  	descr->tx_por           = 0;
  	descr->stat             = USART_ASYNC_STATUS_BUSY;
  	_usart_async_enable_byte_sent_irq(&descr->device);
  
  	return (int32_t)length;
  }
  
  /*
   * \internal Read data from usart interface
   *
   * \param[in] descr The pointer to an io descriptor
   * \param[in] buf A buffer to read data to
   * \param[in] length The size of a buffer
   *
   * \return The number of bytes read.
   */
  static int32_t usart_async_read(struct io_descriptor *const io_descr, uint8_t *const buf, const uint16_t length)
  {
  	uint16_t                       was_read = 0;
  	uint32_t                       num;
  	#pragma GCC diagnostic push
  	#pragma GCC diagnostic ignored "-Wcast-align"
  	struct usart_async_descriptor *descr = CONTAINER_OF(io_descr, struct usart_async_descriptor, io);
  	#pragma GCC diagnostic pop
  
  	ASSERT(descr && buf && length);
  
  	CRITICAL_SECTION_ENTER()
  	num = ringbuffer_num(&descr->rx);
  	CRITICAL_SECTION_LEAVE()
  
  	while ((was_read < num) && (was_read < length)) {
  		ringbuffer_get(&descr->rx, &buf[was_read++]);
  	}
  
  	return (int32_t)was_read;
  }
  
  /**
   * \brief Process "byte is sent" interrupt
   *
   * \param[in] device The pointer to device structure
   */
  static void usart_process_byte_sent(struct _usart_async_device *device)
  {
  	#pragma GCC diagnostic push
  	#pragma GCC diagnostic ignored "-Wcast-align"
  	struct usart_async_descriptor *descr = CONTAINER_OF(device, struct usart_async_descriptor, device);
  	#pragma GCC diagnostic pop
  	if (descr->tx_por != descr->tx_buffer_length) {
  		_usart_async_write_byte(&descr->device, descr->tx_buffer[descr->tx_por++]);
  		_usart_async_enable_byte_sent_irq(&descr->device);
  	} else {
  		_usart_async_enable_tx_done_irq(&descr->device);
  	}
  }
  
  /**
   * \brief Process completion of data sending
   *
   * \param[in] device The pointer to device structure
   */
  static void usart_transmission_complete(struct _usart_async_device *device)
  {
  	#pragma GCC diagnostic push
  	#pragma GCC diagnostic ignored "-Wcast-align"
  	struct usart_async_descriptor *descr = CONTAINER_OF(device, struct usart_async_descriptor, device);
  	#pragma GCC diagnostic pop
  
  	descr->stat = 0;
  	if (descr->usart_cb.tx_done) {
  		descr->usart_cb.tx_done(descr);
  	}
  }
  
  /**
   * \brief Process byte reception
   *
   * \param[in] device The pointer to device structure
   * \param[in] data Data read
   */
  static void usart_fill_rx_buffer(struct _usart_async_device *device, uint8_t data)
  {
  	#pragma GCC diagnostic push
  	#pragma GCC diagnostic ignored "-Wcast-align"
  	struct usart_async_descriptor *descr = CONTAINER_OF(device, struct usart_async_descriptor, device);
  	#pragma GCC diagnostic pop
  
  	ringbuffer_put(&descr->rx, data);
  
  	if (descr->usart_cb.rx_done) {
  		descr->usart_cb.rx_done(descr);
  	}
  }
  
  /**
   * \brief Process error interrupt
   *
   * \param[in] device The pointer to device structure
   */
  static void usart_error(struct _usart_async_device *device)
  {
  	#pragma GCC diagnostic push
  	#pragma GCC diagnostic ignored "-Wcast-align"
  	struct usart_async_descriptor *descr = CONTAINER_OF(device, struct usart_async_descriptor, device);
  	#pragma GCC diagnostic pop
  
  	descr->stat = 0;
  	if (descr->usart_cb.error) {
  		descr->usart_cb.error(descr);
  	}
  }
  
  //@}
  