[U-Boot] previous two e-mails are RFC/demonstration!

[Reinhard Meyer <u-boot@emk-elektronik.de>]

Dear All,
> Dear Albert ARIBAUD,
>
> In message<4CE04585.807@free.fr>  you wrote:
>>
>> Currently start.S sets the stack twice, once before calling
>> board_init_f, and once in relocate_code. Are you suggesting we remove
>> the second sp setting?
>
> As relocation can move the stack to some completely different location
> the SP has to be re-initialized (in this setup, after copying the
> global data to their new location).

In the *most general* case stack and gd will have to be relocated
to SDRAM, since the pre-relocation memory *could* be locked data cache
or some buffer memory that is not free anymore when u-boot is up.

Of course, on SoCs like AT91SAM9 where several (4k - 32k) of SRAM are
available it would be tempting to keep stack and gd just in SRAM. But we
don't want to specialize, we want to generalize...

Best regards,
Reinhard