[U-Boot] U-boot SPL direct Linux boot

[Igor Grinberg <grinberg@compulab.co.il>]

On 07/01/11 12:17, Simon Schwarz wrote:
> Ok, topic ATAGS:
> I see three ways doing ATAGS init for SPL:
> 1. use bootm.c which means init bd correctly and add a bunch of #ifdef
> CONFIG_PRELOADER to it - maybe also to some others i don't have on the
> radar yet.

While this is not clean, it might work good.

> 2. Have ATAGS config in board config file and init it at compile time

This is a problematic approach, because memory size, board revision,
serial number and may be some others are only known in runtime.

> 3. Doing it like Heiko and copy the ATAGS config done by u-boot

This one is probably the most clean way.

> My favourite here is number 2 because it would be faster than  1 and
> won't take so much work and won't clutter the standard u-boot code
> with #ifdefs. Also it is simpler to use than 3. the downside is that
> the section for ATAGS config would be huge and the code could diverge
> over time...

Regarding the device tree on ARM, it is still not fully functional.
Nevertheless, currently there is an attempt ([1] and [2]) to make kernel
work with both, device tree and ATAGS and if I understood correctly,
the ATAGS will have precedence over the DT, so closed source
boot loaders will still work.

[1] - http://www.spinics.net/lists/arm-kernel/msg128172.html
[2] - http://www.spinics.net/lists/arm-kernel/msg129270.html

-- 
Regards,
Igor.