Description

Solution

1. Create a 'CopyData' function placed in 'copydata.c' to copy data sections from flash to their final destination, see (Xilinx XAPP642).
   
   

   void copydata(void) {    int *src_rom = (int *)XPAR_FLASH_MEM0_BASEADDR; // pointer src_rom gets the base address of flash     int *dst_ram = &__data_start; // pointer dst_ram gets the value(address) of .data section    int *end_ram = &__data1_end; // pointer end_ram gets the ending address of .data1 section     while (dst_ram < end_ram) { // copy the data from ROM to RAM      *dst_ram++ = *src_rom++;     }     return;  } /* end of copy.c */  

2. Copy $EDK/sw/lib/ppc405/src/xil-crt0.s to your project directory.
3. Add bl copydata right before bl main in the xil-crt0.s file:
   
   

   /* Call __init */  bl __init  /* copy data section */  bl copydata  /* Let her rip */  bl main  

4. Compile xil-crt0.s and copydata.c in an EDK Shell:
   EDK_Shell> powerpc-eabi-gcc -c copydata.c -c xil-crt0.s
5. Add the -B./<path_to_copydata.o_and_xil-crt0.o_files>/ extra compile switch for your software application.
6. Compile your software application.
7. Extract the data sections to binary format from your software application's ELF:
   powerpc-eabi-objcopy -O binary -j .data -j .data1 executable.elf flash.bin
8. Use flashwriter to write the flash.bin into the flash device starting at the base address.
   Now, when you press the CPU reset, the CopyData function executes and copies the data sections from flash into RAM.

.data : {  . = ALIGN(4);  __data_start = .;  *(.data)  *(.data.*)  *(.gnu.linkonce.d.*)  __data_end = .; } > ilmb_cntlr_dlmb_cntlr   /* create a section */ .datacopy : {  . = ALIGN(4);  __datacopy = .;  . += SIZEOF(.data); } > ilmb_cntlr_dlmb_cntlr 

#include "xparameters.h" #include "stdio.h" #include "xutil.h" //====================================================   volatile int i = 0xDEADBEEF; extern unsigned char __datacopy; extern unsigned char __data_start; extern unsigned char __data_end;   int main (void) {   unsigned char *dataCopyStart = &__datacopy;   unsigned char *dataStart = &__data_start;   unsigned char *dataEnd = &__data_end;     if (i == 0xDEADBEEF)     while(dataStart < dataEnd)       *dataCopyStart++ = *dataStart++;         else     while(dataStart < dataEnd)       *dataStart++ = *dataCopyStart++;    print("-- Entering main() --\r\n");   i = 0;     print("-- Exiting main() --\r\n");     return 0; } 

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