CCS/TMS570LS3137: How to avoid an application updated by the Bootloader from overwriting the content of another application.

Hello QJ Wang,

Thanks for your reply!
Understood, this is indeed the most direct solution.

But is there a way to allow Bootlaoder to restrict oversized application files?
For example, 1nd application was accidentally selected as an application that is larger than expected,
but I do not want the 2nd application to be overwritten by a mistake.

Can the bootloader pre-allocate the Flash memory space that each application can write to?
Such as downloading will not continue to write when the allocated space is exceeded.

Thanks for your help!

Best Regards, Chen Yan-Li

Hi yan-Li,

Yes, you can. Please refer to the function BLInternalFlashStartAddrCheck() in bl_flash.c. This is to check if the application is larger than the flash size. You can modify the code for your application:

//*****************************************************************************
//
//! Checks whether a given start address is valid for a download.
//!
//! This function checks to determine whether the given address is a valid
//! download image start address given the options defined in bl_config.h.
//!
//! \return Returns non-zero if the address is valid or 0 otherwise.
//
//*****************************************************************************
uint32_t
BLInternalFlashStartAddrCheck(uint32_t ulAddr, uint32_t ulImgSize)
{
uint32_t count=0, i;

uint32_t ulWholeFlashSize;

//
// Determine the size of the flash available on the part in use.
//
ulWholeFlashSize = (uint32_t)flash_sector[NUMBEROFSECTORS-1].start + flash_sector[NUMBEROFSECTORS-1].length; /* 3MB */

/* The start address must be at the begining of the sector */
for (i = 0; i < NUMBEROFSECTORS; i++){
if ((ulAddr >= (uint32_t)(flash_sector[i].start)) && (ulAddr < ((uint32_t)flash_sector[i].start + flash_sector[i].length)))
{
count++;
}
}
if (count == 0){
return(0);
}

//
// Is the address we were passed a valid start address? We allow:
//
// 1. Address 0 if configured to update the boot loader.
// 2. The start of the reserved block if parameter space is reserved (to
// allow a download of the parameter block contents).
// 3. The application start address specified in bl_config.h.
//
// The function fails if the address is not one of these, if the image
// size is larger than the available space or if the address is not word
// aligned.
//
if((
#ifdef ENABLE_BL_UPDATE
(ulAddr != 0) &&
#endif
(ulAddr != APP_START_ADDRESS)) ||
((ulAddr + ulImgSize) > ulWholeFlashSize) ||
((ulAddr & 3) != 0))
{
return(0);
}
else {
return(1);
}
}

Hello QJ Wang,

Thanks for your reply!
I tried to modify BLInternalFlashStartAddrCheck () in bl_flash.c,
but the Flash writing method of the Bootloader did not seem to be changed by modifying the Flash sector.
Here's what I modified:

ulWholeFlashSize = (uint32_t)flash_sector[3].start + flash_sector[3].length; /* 3MB */

/* The start address must be at the begining of the sector */
for (i = 0; i < NUMBEROFSECTORS; i++){
if ((ulAddr >= (uint32_t)(flash_sector[3].start)) && (ulAddr < ((uint32_t)flash_sector[3].start + flash_sector[3].length)))
{
count++;
}
}
if (count == 0){
return(0);
}

if((
#ifdef ENABLE_BL_UPDATE
(ulAddr != 0) &&
#endif
(ulAddr != APP_START_ADDRESS)) ||
((ulAddr + ulImgSize) > ulWholeFlashSize) ||
((ulAddr & 3) != 0))
{
return(0);
}
else {
return(1);
}
}

However, the above modifications do not seem to change the sector allocation of Flash.
Are there any incorrect parts of my changes?
Could you give me some suggestions for modification?

Thanks for your help!

Best Regards, Chen Yan-Li