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Altera boot_loader_cfi + SRAM

Altera_Forum
Honored Contributor II
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Hi all, 

 

On my Cyclone III developpement board, I have a fully functionnal uClinux O/S which runs from the SDRAM. 

 

At the present time, the power-up steps are the following : 

 

1. power on 

2. config sof from flash to FPGA 

3. Nios II CPU start at the reset vector (flash), which contain the boot loader 

4. the boot loader copy program image from flash to SDRAM for the zImage 

5. the uncompress loader in our zImage, copy the real kernel image to (sdram base) 

6. kernel start up 

 

Here is the command lines I used with bootloader (flash range 0x00000000 to 0x1ffffff) : 

 

---------------------------------------------------------------------------------- 

> elf2flash --base=0x00000000 --end=0x1ffffff --reset=0x0  

--input=zImage --output=zImage.flash  

--boot=/…/nios2eds/components/altera_nios2/boot_loader_cfi.srec 

> nios2-flash-programmer --base=0x00000000 zImage.flash 

---------------------------------------------------------------------------------- 

 

I know that it is possible to force uClinux to boot from SRAM and the devboard has in fact 4MByte of SRAM... So here is my question : 

 

is it possible to modify the "boot_loader_cfi.srec" from altera in order to copy the zimage from flash to sram, instead of sdram ?? 

 

Thanks for your help !
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