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

[Rogan Dawes]

On 2011/04/20 12:17 PM, Rogan Dawes wrote:
> Now if I can just figure out how to write to my flash using OpenOCD, I
> can hopefully recover.
> 
> Regards,
> 
> Rogan

Phew! Thanks to Albert's sloflash utility, I was finally able to get
something back into my flash, and get the board booting again. What a
relief! :-D

Now I need to solve the problem of placing the _start code at the
address of the reset vector, since I have 3 64kB sectors to play with,
but one of them is 99% empty, other than the reset vector code which
just jumps to _start.

And of course, a mainline u-boot will not fit into just 128kB.

Any thoughts on how to link u-boot to place _start or any other routine
that can jump to _start at 0xffff0000?

I had this suggestion on IRC:

            . = .;
            __u_boot_cmd_start = .;
            .u_boot_cmd : { *(.u_boot_cmd) }
            __u_boot_cmd_end = .;

            . = _start + 0x70000;
            .reset_vector_sect :
            {
                    arch/arm/cpu/arm926ejs/start.o (.reset_vector_sect)
                    *(.reset_vector_sect)
            }



    #include <asm-offsets.h>
    #include <config.h>
    #include <common.h>
    #include <version.h>

    .section    ".reset_vector_sect",#alloc, #execinstr
    _reset_vector:
        b   _start


Although I'm not sure how to interpret it :-)

Regards,

Rogan