[U-Boot] Linux boot and list loading feature

[Simon Schwarz <simonschwarzcor@googlemail.com>]

Hi Aneesh,

On 08/01/2011 02:56 PM, Aneesh V wrote:
> Hi Simon,
>
> On Monday 01 August 2011 04:50 PM, Simon Schwarz wrote:
>> Hi Aneesh,
>>
>> I am working on the OS booting right now and have a bigger change of
>> your code in spl.c in mind.
>>
>> Hope you can say one or two words what you think about it.
>>
>> THE PROBLEM
>> For the direct OS boot and in some other situations - env image e.g., I
>> have to load more than one image in SPL.
>>
>> This can be done by hardcoding these cases and use #ifdef or ifs to
>> switch between them. Or I can implement a general image loading with
>> lists.
>> (This was discussed here:
>> http://article.gmane.org/gmane.comp.boot-loaders.u-boot/102345)
>
> At the outset, wonder why we can not use the default bootargs string in
> the kernel image instead of passing it from the bootloader. For direct
> kernel boot from SPL, that looks like the best option for me. Then we
> will not need all this. Am I missing something?
>
 From the documentation it is mandatory for ARM to pass ATAGS (or FDT I 
assume): http://www.arm.linux.org.uk/developer/booting.php

So I think your solution would work - but IMHO would be too simple.

The beauty is that we can save the config of ATAGS/FDT directly in 
u-boot and pass this image at the next boot to the SPL. This means we 
can boot the exact same configuration with the SPL as with standard 
u-boot - without recompiling the kernel. Trade-off: a more complex SPL.

> best regards,
> Aneesh

Regards
Simon