[U-Boot] u-boot on ARM PIC?

[Ladislav Michl <Ladislav.Michl@seznam.cz>]

On Wed, Jan 13, 2010 at 11:37:19AM +0100, Peter Korsgaard wrote:
> Hi,
> 
> I'll soon start an ARM based project (at91sam9g45), and am looking into
> booting options. I normally use PPC, so I'm not really familiar with the
> finer details of U-Boot on ARM. I would like to use a failsafe setup
> with 2x U-Boot images in NOR flash, and a mini bootloader (probably
> at91bootstrap based) to decide which to use. For that to work nicely,
> U-Boot would have to be PIC (pre-relocation).

Take a look at board/netstar/crcek.S as exactly that is solved there
(you may want to apply NetStar patches I sent to mailing list two weeks ago,
which are being ignored as usual, so this is an usual rant). There are two
images in NOR and only one can be written from Linux. This is done on update
and then board is rebooted. 'Crcek' then verifies images and runs more recent
version. It is up to u-boot to copy itself into lower location.

> I see there's CONFIG_SKIP_RELOCATE_UBOOT + CONFIG_LOWLEVEL_INIT. Can
> someone confirm that U-Boot is PIC on at91 if those two aren't defined,
> E.G. will it boot from any location in NOR?

It boots from any NOR location on OMAP, so it should be the same for AT91.

Best regards,
	ladis