[Buildroot] [PATCH] boot/uboot: add option to define custom dependencies

[Heiko Stübner]

Hi Thomas, Yann,

Am Samstag, 25. April 2020, 23:22:45 CEST schrieb Thomas Petazzoni:
> Hello,
> 
> On Sat, 25 Apr 2020 23:13:50 +0200
> "Yann E. MORIN" <yann.morin.1998 at free.fr> wrote:
> 
> > My opinion on that patch is that i am definitely not in favour of it. If
> > we go that route, then we would have to allow adding any such arbitrary
> > dependencies to a wide range of packages.
> 
> Without necessarily strongly supporting Heiko's patch, I think it is
> important to keep in mind that U-Boot is not a package like any others.
> We offer version selection for U-Boot, custom Git/Subversion repo
> selection, which we do not offer for other packages. U-Boot has
> zillions of forks, support for gazillions platforms each with their own
> funky requirements.
> 
> We've already added a BR2_TARGET_UBOOT_CUSTOM_MAKEOPTS to pass custom
> make options, adding the possibility to add custom dependencies would
> go in the same direction.
> 
> I however agree that this kind of option is a good recipe for people to
> do their own hacks on their side, instead of finding a proper way to do
> it that can be upstreamed to Buildroot.
> 
> > Now, there are two situations:
> > 
> >   - the tool is already in Buildroot: add a new _NEEDS_FOO option like
> >     we already have.
> > 
> >   - the tool is in a br2-external tre: this is in my opinion better
> >     served by working on the evaluation-postpone changes Arnou and I
> >     have been suggesting for quite a while now.
> 
> I think it would make sense to hear about what Heiko's use case exactly
> is, this might help.

the use-case is:
- a u-boot config fragment specifying key-dir and key-hint for signing
  uboot parts - see [0]
- our own package managing these (and other) keys
- and thus us wanting to make sure the key package gets "build" before
  u-boot itself

I'm not overly attached to my patch, but it somehow felt in line with
also the config-fragment option, that allows including other random
fragments into the board config file for the u-boot build.

So yes, the required package is in a br2-external tree. What is this
"evaluation-postpone" thingy?


Thanks
Heiko


[0] https://patchwork.ozlabs.org/project/uboot/patch/20200421002333.111461-6-heiko@sntech.de/
and other patches in that series