[U-Boot] i.MX6: mx6qsabrelite: allow use with Freescale 2.6.38 kernels

[mailander]

On 03/03/2012 10:38, Wolfgang Denk wrote:
> Dear Dirk,
> 
> In message <4F51BBA9.4090608 at googlemail.com> you wrote:
>>
>> Having Freescale working on these quite old and unclean U-Boot and 
>> Kernel versions is a pain. Kernel is an other topic, but with U-Boot, 
>> thanks to the very good work of everybody, we are in a good position 
>> to get rid of the old Freescale U-Boot, now. And get everybody to work 
>> with mainline and create patches against it.
> 
> ACK.
> 
>> So if it helps to apply some backward compatibility to make it easier 
>> for everybody, esp. Freescale, to switch to mainline U-Boot, I think 
>> we should try it.
> 
> Agreed.  If these patches were only for backward compatibility I would
> not complain much.  But they are known to introduce forward incompati-
> bilities with all this MACH_ID stuff, and this is what I would like to
> avoid.
> 
> I think we should make a clear statement that new boards that get
> added should only support DT based configurations.  If really needed,
> legacy MACH_ID support may be kept out of tree.

I think a point here is that boards must not use any macro defined in
mach-types.h, such as machine_is_*.  U-Boot does not need it, and their
usage makes the code strictly dependent from the kernel legacy mach-ids.

If a board defines only CONFIG_MACH_TYPE in its own configuration file,
it should not break if we decide in future to drop it completely.

Best regards,
Stefano Babic