openblt/Target/Source/ARMCM3_LM3S/cpu.c

/****************************************************************************************
|  Description: bootloader cpu module source file
|    File Name: cpu.c
|
|----------------------------------------------------------------------------------------
|                          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 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          */


/****************************************************************************************
* Macro definitions
****************************************************************************************/
#define CPU_USER_PROGRAM_STARTADDR_PTR    ((blt_addr)  0x00004004)
#define CPU_USER_PROGRAM_VECTABLE_OFFSET  ((blt_int32u)0x00004000)

  
/****************************************************************************************
* Register definitions
****************************************************************************************/
/* vector table offset register */
#define SCB_VTOR    (*((volatile blt_int32u *) 0xE000ED08))


/****************************************************************************************
* External functions
****************************************************************************************/
extern void reset_handler(void);                      /* implemented in cstart.s       */


/****************************************************************************************
** NAME:           CpuStartUserProgram
** PARAMETER:      none
** RETURN VALUE:   none
** DESCRIPTION:    Starts the user program, if one is present. In this case this function
**                 does not return. 
**
****************************************************************************************/
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;
  }
  /* release the communication interface */
  ComFree();
  /* remap user program's vector table */
  SCB_VTOR = CPU_USER_PROGRAM_VECTABLE_OFFSET & (blt_int32u)0x1FFFFF80;
  /* 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));
  /* start the user program by activating its reset interrupt service routine */
  pProgResetHandler();
} /*** end of CpuStartUserProgram ***/


/****************************************************************************************
** NAME:           CpuMemCopy
** PARAMETER:      dest destination address for the data.
**                 src  source address of the data.
**                 len  length of the data in bytes.
** RETURN VALUE:   none
** DESCRIPTION:    Copies data from the source to the destination address.
**
****************************************************************************************/
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 ***/


/****************************************************************************************
** NAME:           CpuReset
** PARAMETER:      none
** RETURN VALUE:   none
** DESCRIPTION:    Perform a soft reset of the microcontroller by starting from the reset
**                 ISR.
**
****************************************************************************************/
void CpuReset(void)
{
  /* perform a software reset by calling the reset ISR routine */
  reset_handler();
} /*** end of CpuReset ***/


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