[U-Boot] running u-boot from SDRAM

[Wolfgang Denk]

Dear Roman Mashak,

In message <40a670230809040449q23cdd0c4y5e02210111b87ee6 at mail.gmail.com> you wrote:
> 
> I need to port U-Boot on the platform, consisting of master and
> daughter boards. Master boards runs WinCE; daughter board features
> SoC, based on ARM926EJ-S, on-chip SDRAM and ROM. Master launches
> daughter board by downloading binary image of bootcode in to the
> on-chip SDRAM, then does remap (i.e. 0x0 points at SDRAM) and boot
> loader starts off.

I guess you are aware that SRDAM cannot just be used, instead it must
initialized correctly before you can access it. Your master  is  also
performing this initialization procedure, then?

> Therefore I'm wondering -- will U-Boot be fine with such a boot mode,
> usually systems start from flash (NOR or NAND), but here it's in RAM.
> I believe it should be OK, but just want to make sure.

It doesn't hurt when the device  where  U-Boot  is  booting  from  is
writable.  You  have to take care not to try t<F12>o re-initialize the RAM
in U-Boot, though.

Best regards,

Wolfgang Denk

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