[OE-core] how can i add u-boot-fw-utils to my build without u-boot being part of the build?

[Tom Rini]

On Sun, Aug 21, 2016 at 09:59:22AM -0400, Robert P. J. Day wrote:
> On Fri, 19 Aug 2016, Tom Rini wrote:
> 
> > On Thu, Aug 18, 2016 at 12:41:25PM -0400, Robert P. J. Day wrote:
> > >
> > >   i want to add the u-boot-fw-utils recipe to my current build,
> > > but u-boot is *not* part of the relevant BSP layer -- u-boot is
> > > being configured and built elsewhere, and that's not changing for
> > > the foreseeable future.
> > >
> > >   the good news is that those utilities don't need to have any
> > > info on the default environment for u-boot -- they need only have
> > > access to the environment in flash, and there is a
> > > /etc/fw_env.config file that is all set up and ready to go and
> > > referring to the correct device and offset in flash.
> > >
> > >   so how do i specify that i want to add that recipe to my build,
> > > while saying, "don't worry about the default environment, you
> > > don't need it." can that be done? thanks.
> >
> > The "easy" way out here is to just set a valid (as in, compiles)
> > UBOOT_MACHINE and then not worry about installing U-Boot from the OE
> > build.  You can ASSUME_PROVIDED away u-boot itself, but you still
> > need to have a UBOOT_MACHINE set so that we configure U-Boot before
> > building the tools (And you must configure before building).
> 
>   the problem is that the machine is a custom tweaking of an existing
> platform in u-boot, so that a regular checkout of u-boot won't have a
> defconfig for that machine. the entirety of u-boot for this target
> board is configured and built elsewhere, so i'm just trying to figure
> out what little i need to supply to get a build of those fw-utils in
> my image.
> 
>   i suppose i can just use an existing machine that's compatible --
> beyond that, i assume all i need to supply is a /etc/fw_env.config
> file defining where in flash the environment is to be manipulated.
> 
>   i realize this is a weird scenario, it's just what i have to work
> with for the time being.

This is a fairly common scenario I think.  I'm doing it myself right now
for a customer :)  And what I'm doing is having OE build U-Boot for the
reference platform (and not using that U-Boot) and re-use that config
for building u-boot-fw-utils (which we do need) and providing a good
fw_env.config just like you suggest.

-- 
Tom