/************************************************************************************//**
* \file         Source\ARMCM0_STM32\cpu.c
* \brief        Bootloader cpu module source file.
* \ingroup      Target_ARMCM0_STM32
* \internal
*----------------------------------------------------------------------------------------
*                          C O P Y R I G H T
*----------------------------------------------------------------------------------------
*   Copyright (c) 2016  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 "stm32f0xx.h"                           /* for STM32F0 registers and drivers  */


/****************************************************************************************
* Macro definitions
****************************************************************************************/
/** \brief Pointer to the user program's reset vector. */
#define CPU_USER_PROGRAM_STARTADDR_PTR    ((blt_addr)(NvmGetUserProgBaseAddress() + 0x00000004))
/** \brief Pointer to the user program's vector table. */
#define CPU_USER_PROGRAM_VECTABLE_OFFSET  ((blt_int32u)NvmGetUserProgBaseAddress())
/** \brief Size in bytes of the user program's vector table */
#define CPU_USER_PROGRAM_VECTABLE_SIZE    (0xC0u)
/** \brief Start address of the user program's RAM where its vector table will be copied
 *         to.
 */
#define CPU_USER_PROGRAM_RAM_BASEADDR     ((blt_addr)(0x20000000))


/****************************************************************************************
* Hook functions
****************************************************************************************/
#if (BOOT_CPU_USER_PROGRAM_START_HOOK > 0)
extern blt_bool CpuUserProgramStartHook(void);
#endif


/****************************************************************************************
* External functions
****************************************************************************************/
extern void Reset_Handler(void);                      /* implemented in C-startup      */


/************************************************************************************//**
** \brief     Starts the user program, if one is present. In this case this function
**            does not return.
** \return    none.
**
****************************************************************************************/
void CpuStartUserProgram(void)
{
  void (*pProgResetHandler)(void);

  /* check if a user program is present by verifying the checksum */
  if (NvmVerifyChecksum() == BLT_FALSE)
  {
    /* not a valid user program so it cannot be started */
    return;
  }
#if (BOOT_CPU_USER_PROGRAM_START_HOOK > 0)
  /* invoke callback */
  if (CpuUserProgramStartHook() == BLT_FALSE)
  {
    /* callback requests the user program to not be started */
    return;
  }
#endif
#if (BOOT_COM_ENABLE > 0)
  /* release the communication interface */
  ComFree();
#endif
  /* reset the timer */
  TimerReset();

  /* enable system configuration peripheral, which is needed to remap the RAM later on */
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_SYSCFG, ENABLE);
  /* copy user program vector's to RAM */
  CpuMemCopy(CPU_USER_PROGRAM_RAM_BASEADDR, CPU_USER_PROGRAM_VECTABLE_OFFSET,
             CPU_USER_PROGRAM_VECTABLE_SIZE);
  /* remap RAM so that it also appears at address 0x00000000. this way the user program's
   * vector table in RAM is used instead of the bootloader's vector table in flash.
   */
  SYSCFG_MemoryRemapConfig(SYSCFG_MemoryRemap_SRAM);
  /* set the address where the bootloader needs to jump to. this is the address of
   * the 2nd entry in the user program's vector table. this address points to the
   * user program's reset handler.
   */
  pProgResetHandler = (void(*)(void))(*((blt_addr *)CPU_USER_PROGRAM_STARTADDR_PTR));
  /* The Cortex-M0 core has interrupts enabled out of reset. the bootloader
   * explicitly disables these for security reasons in the C-startup.
   * Enable them here again, so it does not have to be done by the user
   * program.
   */
  __enable_irq();
  /* start the user program by activating its reset interrupt service routine */
  pProgResetHandler();
} /*** end of CpuStartUserProgram ***/


/************************************************************************************//**
** \brief     Copies data from the source to the destination address.
** \param     dest Destination address for the data.
** \param     src  Source address of the data.
** \param     len  length of the data in bytes.
** \return    none.
**
****************************************************************************************/
void CpuMemCopy(blt_addr dest, blt_addr src, blt_int16u len)
{
  blt_int8u *from, *to;

  /* set casted pointers */
  from = (blt_int8u *)src;
  to = (blt_int8u *)dest;

  /* copy all bytes from source address to destination address */
  while (len-- > 0)
  {
    /* store byte value from source to destination */
    *to++ = *from++;
    /* keep the watchdog happy */
    CopService();
  }
} /*** end of CpuMemCopy ***/


/************************************************************************************//**
** \brief     Perform a soft reset of the microcontroller by starting from the reset ISR.
** \return    none.
**
****************************************************************************************/
void CpuReset(void)
{
  /* perform a software reset by calling the reset ISR routine */
  Reset_Handler();
} /*** end of CpuReset ***/


/*********************************** end of cpu.c **************************************/