[yocto] Different u-boot recipes (machine names and provider)

[Jens Lucius]

Hello,

I am working on a custom machine layer, which until now has it´s own 
u-boot recipe for a custom u-boot.

I want to add a recipe for mainline u-boot additional to that. I have 
defined a PREFERRED_PROVIDER_u-boot and 
PREFERRED_PROVIDER_virtual/bootloader which point to the custom u-boot 
to not break the current build, which can be changed to the mainline 
u-boot if needed to build the mainline.

First question: Do I need to define both PREFERRED_PROVIDER (u-boot and 
virtual/bootloader)? I have seen different approaches in different layers.

Now the hard part: custom u-boot and mainline u-boot have different 
UBOOT_MACHINE values for the same hardware. Is it possible to define 
different values for different u-boot recipes? Right now they are 
defined in the machine configurations. Would it be possible (and 
advisable) to define them in the u-boot recipes themselves? Or is there 
another approach ?

Thanks,

Jens