[PATCH openbmc v2] Re-enable out of tree device trees

[Patrick Williams]

On Thu, May 19, 2016 at 11:26:01AM +0930, Joel Stanley wrote:
> Hi Brad,
> 
> On Wed, May 18, 2016 at 12:00 AM, OpenBMC Patches
> <openbmc-patches at stwcx.xyz> wrote:
> > From: Brad Bishop <bradleyb at fuzziesquirrel.com>
> >
> > This snippet was mistakenly removed with 8ef9fee.
> 
> It was intentionally removed.
> 
> > Note that this isn't a matter of policy, it simply enables
> > the option to do it.  The in-tree device tree is still the default.
> >
> > This enables things like workbook or schematic generated device
> > trees.  It also addresses the inevitable fact that the upstream kernel
> > will probably not want device trees for every board in the world.
> 
> As we do development the device tree is strongly coupled to the
> kernel. I think we want to keep the dts in the kernel tree, so that
> changes are made together.
> 
> Secondly, when testing kernels the developer may or may not be using
> the poky environment. This means that the developer writing and
> supporting your kernel is not testing the same code that is running on
> the board.
> 
> We can add every device trees to our kernel tree. As the upstream
> maintainer of the aspeed port, I will also send them all upstream.

I can think of almost a dozen openpower boxes, plus the IBM branded FSP
boxes.  That is before we even start to support x86 and ARM servers.  Do
you really think we are going to want to submit every single device tree
for every single openbmc supported box upstream?  That sounds really
cumbersome for both us and the Linux community.

Yocto already has a mechanism for creating device trees from snippets.
As we start to use the MRW data from the system engineers, I would like to
see us generate many aspects of the device tree from those directly.

> 
> Cheers,
> 
> Joel
> 
> >
> > Signed-off-by: Brad Bishop <bradleyb at fuzziesquirrel.com>
> > ---
> >  meta-phosphor/common/recipes-kernel/linux/linux-obmc_4.4.bb | 10 ++++++++++
> >  1 file changed, 10 insertions(+)
> >
> > diff --git a/meta-phosphor/common/recipes-kernel/linux/linux-obmc_4.4.bb b/meta-phosphor/common/recipes-kernel/linux/linux-obmc_4.4.bb
> > index 24cde9f..945b43d 100644
> > --- a/meta-phosphor/common/recipes-kernel/linux/linux-obmc_4.4.bb
> > +++ b/meta-phosphor/common/recipes-kernel/linux/linux-obmc_4.4.bb
> > @@ -18,3 +18,13 @@ COMPATIBLE_MACHINE_${MACHINE} = "openbmc"
> >
> >  inherit kernel
> >  require recipes-kernel/linux/linux-yocto.inc
> > +
> > +do_patch_append() {
> > +        for DTB in "${KERNEL_DEVICETREE}"; do
> > +               DT=`basename ${DTB} .dtb`
> > +                if [ -r "${WORKDIR}/${DT}.dts" ]; then
> > +                        cp ${WORKDIR}/${DT}.dts \
> > +                                ${STAGING_KERNEL_DIR}/arch/${ARCH}/boot/dts
> > +               fi
> > +       done
> > +}
> > --
> > 2.8.2
> >
> >
> > _______________________________________________
> > openbmc mailing list
> > openbmc at lists.ozlabs.org
> > https://lists.ozlabs.org/listinfo/openbmc
> _______________________________________________
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> openbmc at lists.ozlabs.org
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-- 
Patrick Williams
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