/************************************************************************************//**
* \file         Source\ARMCM3_EFM32\uart.c
* \brief        Bootloader UART communication interface source file.
* \ingroup      Target_ARMCM3_EFM32
* \internal
*----------------------------------------------------------------------------------------
*                          C O P Y R I G H T
*----------------------------------------------------------------------------------------
*   Copyright (c) 2012  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 "boot.h"                                /* bootloader generic header          */
#include "efm32.h"
#include "efm32_cmu.h"
#include "efm32_gpio.h"
#include "efm32_leuart.h"


#if (BOOT_COM_UART_ENABLE > 0)
/****************************************************************************************
* Macro definitions
****************************************************************************************/
/** \brief Timeout time for the reception of a CTO packet. The timer is started upon
 *         reception of the first packet byte.
 */
#define UART_CTO_RX_PACKET_TIMEOUT_MS (100u)
/** \brief Timeout for transmitting a byte in milliseconds. */
#define UART_BYTE_TX_TIMEOUT_MS       (10u)


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


/************************************************************************************//**
** \brief     Initializes the UART communication interface.
** \return    none.
**
****************************************************************************************/
void UartInit(void)
{
  LEUART_Init_TypeDef init = LEUART_INIT_DEFAULT;

  /* currently, only LEUART1 is supported */
  ASSERT_CT(BOOT_COM_UART_CHANNEL_INDEX == 1);
  /* max baudrate for LEUART is 9600 bps */
  ASSERT_CT(BOOT_COM_UART_BAUDRATE <= 9600);
  /* configure GPIO pins */
  CMU_ClockEnable(cmuClock_GPIO, true);
  /* to avoid false start, configure output as high */
  GPIO_PinModeSet(gpioPortC, 6, gpioModePushPull, 1);
  GPIO_PinModeSet(gpioPortC, 7, gpioModeInput, 0);
  /* enable CORE LE clock in order to access LE modules */
  CMU_ClockEnable(cmuClock_CORELE, true);
  /* select LFXO for LEUARTs (and wait for it to stabilize) */
  CMU_ClockSelectSet(cmuClock_LFB, cmuSelect_LFXO);
  /* do not prescale clock */
  CMU_ClockDivSet(cmuClock_LEUART1, cmuClkDiv_1);
  /* enable LEUART1 clock */
  CMU_ClockEnable(cmuClock_LEUART1, true);
  /* configure LEUART */
  init.enable = leuartDisable;
  LEUART_Init(LEUART1, &init);
  LEUART_BaudrateSet(LEUART1, 0, BOOT_COM_UART_BAUDRATE);
  /* enable pins at default location */
  LEUART1->ROUTE = LEUART_ROUTE_RXPEN | LEUART_ROUTE_TXPEN;
  /* clear previous RX interrupts */
  LEUART_IntClear(LEUART1, LEUART_IF_RXDATAV);
  /* finally enable it */
  LEUART_Enable(LEUART1, leuartEnable);
} /*** end of UartInit ***/


/************************************************************************************//**
** \brief     Transmits a packet formatted for the communication interface.
** \param     data Pointer to byte array with data that it to be transmitted.
** \param     len  Number of bytes that are to be transmitted.
** \return    none.
**
****************************************************************************************/
void UartTransmitPacket(blt_int8u *data, blt_int8u len)
{
  blt_int16u data_index;
  blt_bool result;

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

  /* first transmit the length of the packet */
  result = UartTransmitByte(len);
  ASSERT_RT(result == 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 */
    result = UartTransmitByte(data[data_index]);
    ASSERT_RT(result == BLT_TRUE);
  }
} /*** end of UartTransmitPacket ***/


/************************************************************************************//**
** \brief     Receives a communication interface packet if one is present.
** \param     data Pointer to byte array where the data is to be stored.
** \param     len Pointer where the length of the packet is to be stored.
** \return    BLT_TRUE if a packet was received, BLT_FALSE otherwise.
**
****************************************************************************************/
blt_bool UartReceivePacket(blt_int8u *data, blt_int8u *len)
{
  static blt_int8u xcpCtoReqPacket[BOOT_COM_UART_RX_MAX_DATA+1];  /* one extra for length */
  static blt_int8u xcpCtoRxLength;
  static blt_bool  xcpCtoRxInProgress = BLT_FALSE;
  static blt_int32u xcpCtoRxStartTime = 0;

  /* start of cto packet received? */
  if (xcpCtoRxInProgress == BLT_FALSE)
  {
    /* store the message length when received */
    if (UartReceiveByte(&xcpCtoReqPacket[0]) == BLT_TRUE)
    {
      if ( (xcpCtoReqPacket[0] > 0) &&
           (xcpCtoReqPacket[0] <= BOOT_COM_UART_RX_MAX_DATA) )
      {
        /* store the start time */
        xcpCtoRxStartTime = TimerGet();
        /* reset packet data count */
        xcpCtoRxLength = 0;
        /* indicate that a cto packet is being received */
        xcpCtoRxInProgress = BLT_TRUE;
      }
    }
  }
  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;
        /* set the packet length */
        *len = xcpCtoRxLength;
        /* packet reception complete */
        return BLT_TRUE;
      }
    }
    else
    {
      /* check packet reception timeout */
      if (TimerGet() > (xcpCtoRxStartTime + UART_CTO_RX_PACKET_TIMEOUT_MS))
      {
        /* cancel cto packet reception due to timeout. note that that automaticaly
         * discards the already received packet bytes, allowing the host to retry.
         */
        xcpCtoRxInProgress = BLT_FALSE;
      }
    }
  }
  /* packet reception not yet complete */
  return BLT_FALSE;
} /*** end of UartReceivePacket ***/


/************************************************************************************//**
** \brief     Receives a communication interface byte if one is present.
** \param     data Pointer to byte where the data is to be stored.
** \return    BLT_TRUE if a byte was received, BLT_FALSE otherwise.
**
****************************************************************************************/
static blt_bool UartReceiveByte(blt_int8u *data)
{
  blt_bool result = BLT_FALSE;

  /* check to see if a new bytes was received */
  if ((LEUART1->IF & LEUART_IF_RXDATAV) != 0)
  {
    /* store the received data byte and set return value to positive */
    *data = LEUART_Rx(LEUART1);
    result = BLT_TRUE;
  }
  /* inform caller about the result */
  return result;
} /*** end of UartReceiveByte ***/


/************************************************************************************//**
** \brief     Transmits a communication interface byte.
** \param     data Value of byte that is to be transmitted.
** \return    BLT_TRUE if the byte was transmitted, BLT_FALSE otherwise.
**
****************************************************************************************/
static blt_bool UartTransmitByte(blt_int8u data)
{
  blt_int32u timeout;
  blt_bool result = BLT_TRUE;

  /* check if tx holding register can accept new data */
  if ((LEUART1->STATUS & LEUART_STATUS_TXBL) == 0)
  {
    /* UART not ready. should not happen */
    return BLT_FALSE;
  }
  /* write byte to transmit holding register */
  LEUART_Tx(LEUART1, data);
  /* wait for tx holding register to be empty */
  while ((LEUART1->STATUS & LEUART_STATUS_TXBL) == 0)
  {
    /* keep the watchdog happy */
    CopService();
    /* break loop upon timeout. this would indicate a hardware failure. */
    if (TimerGet() > timeout)
    {
      result = BLT_FALSE;
      break;
    }
  }
  /* give the result back to the caller */
  return result;
} /*** end of UartTransmitByte ***/
#endif /* BOOT_COM_UART_ENABLE > 0 */


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