/************************************************************************************//**
* \file         Demo/ARMCM0_STM32G0_Nucleo_G071RB_Keil/Prog/boot.c
* \brief        Demo program bootloader interface source file.
* \ingroup      Prog_ARMCM0_STM32G0_Nucleo_G071RB_Keil
* \internal
*----------------------------------------------------------------------------------------
*                          C O P Y R I G H T
*----------------------------------------------------------------------------------------
*   Copyright (c) 2019  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 have received a copy of the GNU General Public License along with OpenBLT. It 
* should be located in ".\Doc\license.html". If not, contact Feaser to obtain a copy.
* 
* \endinternal
****************************************************************************************/

/****************************************************************************************
* Include files
****************************************************************************************/
#include "header.h"                                    /* generic header               */


/****************************************************************************************
* Function prototypes
****************************************************************************************/
#if (BOOT_COM_RS232_ENABLE > 0)
static void BootComRs232Init(void);
static void BootComRs232CheckActivationRequest(void);
#endif


/************************************************************************************//**
** \brief     Initializes the communication interface.
** \return    none.
**
****************************************************************************************/
void BootComInit(void)
{
#if (BOOT_COM_RS232_ENABLE > 0)
  BootComRs232Init();
#endif
} /*** end of BootComInit ***/


/************************************************************************************//**
** \brief     Receives the CONNECT request from the host, which indicates that the
**            bootloader should be activated and, if so, activates it.
** \return    none.
**
****************************************************************************************/
void BootComCheckActivationRequest(void)
{
#if (BOOT_COM_RS232_ENABLE > 0)
  BootComRs232CheckActivationRequest();
#endif
} /*** end of BootComCheckActivationRequest ***/


/************************************************************************************//**
** \brief     Bootloader activation function.
** \return    none.
**
****************************************************************************************/
void BootActivate(void)
{
  /* perform software reset to activate the bootoader again */
  NVIC_SystemReset();
} /*** end of BootActivate ***/


#if (BOOT_COM_RS232_ENABLE > 0)
/****************************************************************************************
*     U N I V E R S A L   A S Y N C H R O N O U S   R X   T X   I N T E R F A C E
****************************************************************************************/

/****************************************************************************************
* Macro definitions
****************************************************************************************/
/** \brief Timeout time for the reception of a CTO packet. The timer is started upon
 *         reception of the first packet byte.
 */
#define RS232_CTO_RX_PACKET_TIMEOUT_MS (100u)


/****************************************************************************************
* Local data declarations
****************************************************************************************/
/** \brief UART handle to be used in API calls. */
static UART_HandleTypeDef rs232Handle;


/****************************************************************************************
* Function prototypes
****************************************************************************************/
static unsigned char Rs232ReceiveByte(unsigned char *data);


/************************************************************************************//**
** \brief     Initializes the UART communication interface.
** \return    none.
**
****************************************************************************************/
static void BootComRs232Init(void)
{
  /* Configure UART peripheral. */
  rs232Handle.Instance            = USART2;
  rs232Handle.Init.BaudRate       = BOOT_COM_RS232_BAUDRATE;
  rs232Handle.Init.WordLength     = UART_WORDLENGTH_8B;
  rs232Handle.Init.StopBits       = UART_STOPBITS_1;
  rs232Handle.Init.Parity         = UART_PARITY_NONE;
  rs232Handle.Init.HwFlowCtl      = UART_HWCONTROL_NONE;
  rs232Handle.Init.Mode           = UART_MODE_TX_RX;
  rs232Handle.Init.OverSampling   = UART_OVERSAMPLING_16;
  rs232Handle.Init.OneBitSampling = UART_ONE_BIT_SAMPLE_ENABLE;
  rs232Handle.Init.ClockPrescaler = UART_PRESCALER_DIV1;
  /* Initialize the UART peripheral. */
  HAL_UART_Init(&rs232Handle);
} /*** end of BootComRs232Init ***/


/************************************************************************************//**
** \brief     Receives the CONNECT request from the host, which indicates that the
**            bootloader should be activated and, if so, activates it.
** \return    none.
**
****************************************************************************************/
static void BootComRs232CheckActivationRequest(void)
{
  static unsigned char xcpCtoReqPacket[BOOT_COM_RS232_RX_MAX_DATA+1];
  static unsigned char xcpCtoRxLength;
  static unsigned char xcpCtoRxInProgress = 0;
  static unsigned long xcpCtoRxStartTime = 0;

  /* start of cto packet received? */
  if (xcpCtoRxInProgress == 0)
  {
    /* store the message length when received */
    if (Rs232ReceiveByte(&xcpCtoReqPacket[0]) == 1)
    {
      /* check that the length has a valid value. it should not be 0 */
      if ( (xcpCtoReqPacket[0] > 0) &&
           (xcpCtoReqPacket[0] <= BOOT_COM_RS232_RX_MAX_DATA) )
      {
        /* store the start time */
        xcpCtoRxStartTime = TimerGet();
        /* indicate that a cto packet is being received */
        xcpCtoRxInProgress = 1;
        /* reset packet data count */
        xcpCtoRxLength = 0;
      }
    }
  }
  else
  {
    /* store the next packet byte */
    if (Rs232ReceiveByte(&xcpCtoReqPacket[xcpCtoRxLength+1]) == 1)
    {
      /* increment the packet data count */
      xcpCtoRxLength++;

      /* check to see if the entire packet was received */
      if (xcpCtoRxLength == xcpCtoReqPacket[0])
      {
        /* done with cto packet reception */
        xcpCtoRxInProgress = 0;

        /* check if this was an XCP CONNECT command */
        if ((xcpCtoReqPacket[1] == 0xff) && (xcpCtoRxLength == 2))
        {
          /* connection request received so start the bootloader */
          BootActivate();
        }
      }
    }
    else
    {
      /* check packet reception timeout */
      if (TimerGet() > (xcpCtoRxStartTime + RS232_CTO_RX_PACKET_TIMEOUT_MS))
      {
        /* cancel cto packet reception due to timeout. note that this automatically
         * discards the already received packet bytes, allowing the host to retry.
         */
        xcpCtoRxInProgress = 0;
      }
    }
  }
} /*** end of BootComRs232CheckActivationRequest ***/


/************************************************************************************//**
** \brief     Receives a communication interface byte if one is present.
** \param     data Pointer to byte where the data is to be stored.
** \return    1 if a byte was received, 0 otherwise.
**
****************************************************************************************/
static unsigned char Rs232ReceiveByte(unsigned char *data)
{
  HAL_StatusTypeDef result;

  /* receive a byte in a non-blocking manner */
  result = HAL_UART_Receive(&rs232Handle, data, 1, 0);
  /* process the result */
  if (result == HAL_OK)
  {
    /* success */
    return 1;
  }
  /* error occurred */
  return 0;
} /*** end of Rs232ReceiveByte ***/
#endif /* BOOT_COM_RS232_ENABLE > 0 */


/*********************************** end of boot.c *************************************/