/****************************************************************************************
|  Description: bootloader UART communication interface source file
|    File Name: uart.c
|
|----------------------------------------------------------------------------------------
|                          C O P Y R I G H T
|----------------------------------------------------------------------------------------
|   Copyright (c) 2013  by Feaser    http://www.feaser.com    All rights reserved
|
|----------------------------------------------------------------------------------------
|                            L I C E N S E
|----------------------------------------------------------------------------------------
| This file is part of OpenBLT. OpenBLT 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.
|
| OpenBLT 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 OpenBLT.
| If not, see <http://www.gnu.org/licenses/>.
|
| A special exception to the GPL is included to allow you to distribute a combined work 
| that includes OpenBLT without being obliged to provide the source code for any 
| proprietary components. The exception text is included at the bottom of the license
| file <license.html>.
| 
****************************************************************************************/

/****************************************************************************************
* Include files
****************************************************************************************/
#include "boot.h"                                /* bootloader generic header          */
#include "stm32f4xx.h"                           /* STM32 registers                    */
#include "stm32f4xx_conf.h"                      /* STM32 peripheral drivers           */


#if (BOOT_COM_UART_ENABLE > 0)
/****************************************************************************************
* Macro definitions
****************************************************************************************/
/* map the configured UART channel index to the STM32's USART peripheral */
#if (BOOT_COM_UART_CHANNEL_INDEX == 0)
#define USART_CHANNEL   USART1
#elif (BOOT_COM_UART_CHANNEL_INDEX == 1)
#define USART_CHANNEL   USART2
#elif (BOOT_COM_UART_CHANNEL_INDEX == 2)
#define USART_CHANNEL   USART3
#elif (BOOT_COM_UART_CHANNEL_INDEX == 3)
#define USART_CHANNEL   USART4
#elif (BOOT_COM_UART_CHANNEL_INDEX == 4)
#define USART_CHANNEL   USART5
#elif (BOOT_COM_UART_CHANNEL_INDEX == 5)
#define USART_CHANNEL   USART6
#endif


/****************************************************************************************
* Function prototypes
****************************************************************************************/
static blt_bool UartReceiveByte(blt_int8u *data);
static blt_bool UartTransmitByte(blt_int8u data);


/****************************************************************************************
** NAME:           UartInit
** PARAMETER:      none
** RETURN VALUE:   none
** DESCRIPTION:    Initializes the UART communication interface
**
****************************************************************************************/
void UartInit(void)
{
  USART_InitTypeDef USART_InitStructure;

  /* the current implementation supports USART1 - USART6. throw an assertion error in 
   * case a different UART channel is configured.  
   */
  ASSERT_CT((BOOT_COM_UART_CHANNEL_INDEX == 0) ||
            (BOOT_COM_UART_CHANNEL_INDEX == 1) ||
            (BOOT_COM_UART_CHANNEL_INDEX == 2) ||
            (BOOT_COM_UART_CHANNEL_INDEX == 3) ||
            (BOOT_COM_UART_CHANNEL_INDEX == 4) ||
            (BOOT_COM_UART_CHANNEL_INDEX == 5)); 
  /* initialize the uart for the specified communication speed */
  USART_InitStructure.USART_BaudRate = BOOT_COM_UART_BAUDRATE;
  USART_InitStructure.USART_WordLength = USART_WordLength_8b;
  USART_InitStructure.USART_StopBits = USART_StopBits_1;
  USART_InitStructure.USART_Parity = USART_Parity_No;
  USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
  USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;
  USART_Init(USART_CHANNEL, &USART_InitStructure);
  /* enable UART */
  USART_Cmd(USART_CHANNEL, ENABLE);
} /*** end of UartInit ***/


/****************************************************************************************
** NAME:           UartTransmitPacket
** PARAMETER:      data pointer to byte array with data that it to be transmitted.
**                 len  number of bytes that are to be transmitted.
** RETURN VALUE:   none
** DESCRIPTION:    Transmits a packet formatted for the communication interface.
**
****************************************************************************************/
void UartTransmitPacket(blt_int8u *data, blt_int8u len)
{
  blt_int16u data_index;

  /* verify validity of the len-paramenter */
  ASSERT_RT(len <= BOOT_COM_TX_MAX_DATA);  

  /* first transmit the length of the packet */  
  ASSERT_RT(UartTransmitByte(len) == BLT_TRUE);  
  
  /* transmit all the packet bytes one-by-one */
  for (data_index = 0; data_index < len; data_index++)
  {
    /* keep the watchdog happy */
    CopService();
    /* write byte */
    ASSERT_RT(UartTransmitByte(data[data_index]) == BLT_TRUE);  
  }
} /*** end of UartTransmitPacket ***/


/****************************************************************************************
** NAME:           UartReceivePacket
** PARAMETER:      data pointer to byte array where the data is to be stored.
** RETURN VALUE:   BLT_TRUE if a packet was received, BLT_FALSE otherwise.
** DESCRIPTION:    Receives a communication interface packet if one is present.
**
****************************************************************************************/
blt_bool UartReceivePacket(blt_int8u *data)
{
  static blt_int8u xcpCtoReqPacket[XCP_CTO_PACKET_LEN+1];  /* one extra for length */
  static blt_int8u xcpCtoRxLength;
  static blt_bool  xcpCtoRxInProgress = BLT_FALSE;

  /* start of cto packet received? */
  if (xcpCtoRxInProgress == BLT_FALSE)
  {
    /* store the message length when received */
    if (UartReceiveByte(&xcpCtoReqPacket[0]) == BLT_TRUE)
    {
      /* indicate that a cto packet is being received */
      xcpCtoRxInProgress = BLT_TRUE;

      /* reset packet data count */
      xcpCtoRxLength = 0;
    }
  }
  else
  {
    /* store the next packet byte */
    if (UartReceiveByte(&xcpCtoReqPacket[xcpCtoRxLength+1]) == BLT_TRUE)
    {
      /* increment the packet data count */
      xcpCtoRxLength++;

      /* check to see if the entire packet was received */
      if (xcpCtoRxLength == xcpCtoReqPacket[0])
      {
        /* copy the packet data */
        CpuMemCopy((blt_int32u)data, (blt_int32u)&xcpCtoReqPacket[1], xcpCtoRxLength);        
        /* done with cto packet reception */
        xcpCtoRxInProgress = BLT_FALSE;

        /* packet reception complete */
        return BLT_TRUE;
      }
    }
  }
  /* packet reception not yet complete */
  return BLT_FALSE;
} /*** end of UartReceivePacket ***/


/****************************************************************************************
** NAME:           UartReceiveByte
** PARAMETER:      data pointer to byte where the data is to be stored.
** RETURN VALUE:   BLT_TRUE if a byte was received, BLT_FALSE otherwise.
** DESCRIPTION:    Receives a communication interface byte if one is present.
**
****************************************************************************************/
static blt_bool UartReceiveByte(blt_int8u *data)
{
  /* check flag to see if a byte was received */
  if (USART_GetFlagStatus(USART_CHANNEL, USART_FLAG_RXNE) == SET)
  {
    /* retrieve and store the newly received byte */
    *data = (unsigned char)USART_ReceiveData(USART_CHANNEL);
    /* all done */
    return BLT_TRUE;
  }
  /* still here to no new byte received */
  return BLT_FALSE;
} /*** end of UartReceiveByte ***/


/****************************************************************************************
** NAME:           UartTransmitByte
** PARAMETER:      data value of byte that is to be transmitted.
** RETURN VALUE:   BLT_TRUE if the byte was transmitted, BLT_FALSE otherwise.
** DESCRIPTION:    Transmits a communication interface byte.
**
****************************************************************************************/
static blt_bool UartTransmitByte(blt_int8u data)
{
  /* check if tx holding register can accept new data */
  if (USART_GetFlagStatus(USART_CHANNEL, USART_FLAG_TXE) == RESET)
  {
    /* UART not ready. should not happen */
    return BLT_FALSE;
  }
  /* write byte to transmit holding register */
  USART_SendData(USART_CHANNEL, data);
  /* wait for tx holding register to be empty */
  while (USART_GetFlagStatus(USART_CHANNEL, USART_FLAG_TXE) == RESET) 
  { 
    ;
  }
  /* byte transmitted */
  return BLT_TRUE;
} /*** end of UartTransmitByte ***/
#endif /* BOOT_COM_UART_ENABLE > 0 */


/*********************************** end of uart.c *************************************/