[U-Boot] How does u-boot know where to put its start code?

[Hebbar, Gururaja]

Hi,

On Wed, Apr 20, 2011 at 02:43:23, Rogan Dawes wrote:
> Hi folks,
> 
> I'm trying to understand a bit more about how u-boot creates the image, such that the CPU reset vector is pointing to the right piece of code when it is reset.
> 
> i.e. my DNS323 (Orion5x) has a reset vector of 0xffff0000. But for the life of me, I can't find anywhere that actually references that value to place the start code at that point.
> 

Placing the final boot image is left to user who flashes/burns it board. But it should be same as _TEXT_BASE (this is being removed now. Orion5x is arm based). Also look at <u-boot-src>\arch\arm\cpu\arm926ejs\start.S & <u-boot-src>\arch\arm\cpu\arm926ejs\u-boot.lds for more info on how linker is instructed to place the starting code at predefined address.

> I'm basically trying to make sure that my CONFIG_SYS_TEXT_BASE is correct (the address in the flash to which I write the whole u-boot.bin file, right?.
> 
This is passed to linker as the entry point.

> Thanks
> 
> Rogan


Regards, 
Gururaja