Hi,
I am currently developping a custom bootloader to flash my app with STM32H7A3ZIx / SDMMC / FATFS with DMA template
It fetch a binary (*.bin) from an SD card, read maximum BUFFER_SIZE (=8192) and stores it in a uint8_t RAM_Buf[BUFFER_SIZE] array (8KB).
The reading with FATFS function f_read(&SDFile, RAM_Buf, BUFFER_SIZE, (uint_t *)&bytesread fills the RAM_Buf with the correct datas from my binary.
The problem is that the f_read erase my stack, so the locals variables like readflag are overwritted. (1 at init, but 0 after the f_read). Here's the code (from X-CUBE-IAP-SD) :
#define BUFFER_SIZE ((uint16_t)1 * 8192)
static uint32_t RamAddress = 0x00;
static uint8_t RAM_Buf[BUFFER_SIZE] = {0x00};
#define TRUE 1
#define FALSE 0
/**
* @brief Programs the internal Flash memory.
* @param None
* @retval None
*/
static void COMMAND_ProgramFlashMemory(void)
{
uint16_t bytesread = 0;
uint8_t readflag = TRUE;
/* RAM Address Initialization */
RamAddress = (uint32_t)&RAM_Buf;
/* Erase address init */
LastPGAddress = FLASH_USER_START_ADDR;
/* While file still contain data */
while ((readflag == TRUE))
{
/* Read maximum "BUFFER_SIZE" Kbyte from the selected file */
if (f_read(&SDFile, RAM_Buf, BUFFER_SIZE, (uint_t *)&bytesread) != FR_OK) // after the first execution of the f_read, readflag is overwritten to 0
{
Error_Handler();
}
/* The read data < "BUFFER_SIZE" Kbyte */
if (bytesread < BUFFER_SIZE)
{
readflag = FALSE;
}
if (FLASH_If_Write(LastPGAddress, (uint32_t *)RamAddress, bytesread / 4) != 0x00)
{
/* Flash programming error */
Error_Handler();
}
/* Update last programmed address value */
LastPGAddress = LastPGAddress + bytesread;
}
}
I cannot pinpoint why the stack is overwritted. I have tried to increase my stack, use a ram section dedicated to the RAM_Buf, but it does not fix the problem.
CPU ICache/DCache is disabled.
Here's my linker file :
/* Entry Point */
ENTRY(Reset_Handler)
/* Highest address of the user mode stack */
_estack = ORIGIN(RAM) + LENGTH(RAM); /* end of "RAM" Ram type memory */
_Min_Heap_Size = 0x3000 ; /* required amount of heap */
_Min_Stack_Size = 0x2000 ; /* required amount of stack */
/* Memories definition */
MEMORY
{
DTCMRAM (xrw) : ORIGIN = 0x20000000, LENGTH = 128K
ITCMRAM (xrw) : ORIGIN = 0x00000000, LENGTH = 64K
RAM (xrw) : ORIGIN = 0x24000000, LENGTH = 1024K
FLASH (rx) : ORIGIN = 0x8000000, LENGTH = 128K
}
/* Sections */
SECTIONS
{
/* The startup code into "FLASH" Rom type memory */
.isr_vector :
{
. = ALIGN(4);
KEEP(*(.isr_vector)) /* Startup code */
. = ALIGN(4);
} >FLASH
/* The program code and other data into "FLASH" Rom type memory */
.text :
{
. = ALIGN(4);
*(.text) /* .text sections (code) */
*(.text*) /* .text* sections (code) */
*(.glue_7) /* glue arm to thumb code */
*(.glue_7t) /* glue thumb to arm code */
*(.eh_frame)
KEEP (*(.init))
KEEP (*(.fini))
. = ALIGN(4);
_etext = .; /* define a global symbols at end of code */
} >FLASH
/* Constant data into "FLASH" Rom type memory */
.rodata :
{
. = ALIGN(4);
*(.rodata) /* .rodata sections (constants, strings, etc.) */
*(.rodata*) /* .rodata* sections (constants, strings, etc.) */
. = ALIGN(4);
} >FLASH
.ARM.extab : {
. = ALIGN(4);
*(.ARM.extab* .gnu.linkonce.armextab.*)
. = ALIGN(4);
} >FLASH
.ARM : {
. = ALIGN(4);
__exidx_start = .;
*(.ARM.exidx*)
__exidx_end = .;
. = ALIGN(4);
} >FLASH
.preinit_array :
{
. = ALIGN(4);
PROVIDE_HIDDEN (__preinit_array_start = .);
KEEP (*(.preinit_array*))
PROVIDE_HIDDEN (__preinit_array_end = .);
. = ALIGN(4);
} >FLASH
.init_array :
{
. = ALIGN(4);
PROVIDE_HIDDEN (__init_array_start = .);
KEEP (*(SORT(.init_array.*)))
KEEP (*(.init_array*))
PROVIDE_HIDDEN (__init_array_end = .);
. = ALIGN(4);
} >FLASH
.fini_array :
{
. = ALIGN(4);
PROVIDE_HIDDEN (__fini_array_start = .);
KEEP (*(SORT(.fini_array.*)))
KEEP (*(.fini_array*))
PROVIDE_HIDDEN (__fini_array_end = .);
. = ALIGN(4);
} >FLASH
/* Used by the startup to initialize data */
_sidata = LOADADDR(.data);
/* Initialized data sections into "RAM" Ram type memory */
.data :
{
. = ALIGN(4);
_sdata = .; /* create a global symbol at data start */
*(.data) /* .data sections */
*(.data*) /* .data* sections */
*(.RamFunc) /* .RamFunc sections */
*(.RamFunc*) /* .RamFunc* sections */
. = ALIGN(4);
_edata = .; /* define a global symbol at data end */
} >RAM AT> FLASH
/* Uninitialized data section into "RAM" Ram type memory */
. = ALIGN(4);
.bss :
{
/* This is used by the startup in order to initialize the .bss section */
_sbss = .; /* define a global symbol at bss start */
__bss_start__ = _sbss;
*(.bss)
*(.bss*)
*(COMMON)
. = ALIGN(4);
_ebss = .; /* define a global symbol at bss end */
__bss_end__ = _ebss;
} >RAM
/* User_heap_stack section, used to check that there is enough "RAM" Ram type memory left */
._user_heap_stack :
{
. = ALIGN(8);
PROVIDE ( end = . );
PROVIDE ( _end = . );
. = . + _Min_Heap_Size;
. = . + _Min_Stack_Size;
. = ALIGN(8);
} >RAM
/* Remove information from the compiler libraries */
/DISCARD/ :
{
libc.a ( * )
libm.a ( * )
libgcc.a ( * )
}
.ARM.attributes 0 : { *(.ARM.attributes) }
}
Thanks.
