Hi Rahul,
On Tuesday, 13 June 2017 09:13:12 PDT Rahul Bedarkar wrote:
> Hi Paul,
>
> On Fri, Jun 2, 2017 at 11:50 PM, Paul Burton <paul.burton@xxxxxxxxxx> wrote:
> > When building a FIT image we may want the kernel to build multiple .dtb
> > files, but we don't want to build them all into the kernel binary as
> > object files since they'll instead be included in the FIT image.
> >
> > Commit daa10170da27 ("MIPS: DTS: img: add device tree for Marduk board")
> > however created arch/mips/boot/dts/img/Makefile with a line that builds
> > any enabled .dtb files into the kernel. Remove this & build the
> > pistachio object specifically, in preparation for adding .dtb targets
> > which we don't want to build into the kernel.
> >
> > Signed-off-by: Paul Burton <paul.burton@xxxxxxxxxx>
> > Cc: Rahul Bedarkar <rahul.bedarkar@xxxxxxxxxx>
> > Cc: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
> > Cc: linux-mips@xxxxxxxxxxxxxx
> >
> > ---
> >
> > Changes in v4:
> > - New patch.
> >
> > Changes in v3: None
> > Changes in v2: None
> >
> > arch/mips/boot/dts/img/Makefile | 3 +--
> > 1 file changed, 1 insertion(+), 2 deletions(-)
>
> It looks good to me.
>
> Reviewed-by: Rahul Bedarkar <rahulbedarkar89@xxxxxxxxx>
Thanks for reviewing :)
> > diff --git a/arch/mips/boot/dts/img/Makefile
> > b/arch/mips/boot/dts/img/Makefile index 69a65f0f82d2..c178cf56f5b8 100644
> > --- a/arch/mips/boot/dts/img/Makefile
> > +++ b/arch/mips/boot/dts/img/Makefile
> > @@ -1,6 +1,5 @@
> >
> > dtb-$(CONFIG_MACH_PISTACHIO) += pistachio_marduk.dtb
> >
> > -
> > -obj-y += $(patsubst %.dtb, %.dtb.o, $(dtb-y))
>
> It was probably copy/paste from other board Makefiles. But If I
> understand it correctly, please correct me if I am wrong, linking of
> object file of device tree to kernel image is useful if boot loader
> doesn't support loading external device tree and in that case kernel
> can use inbuilt device tree.
>
> Thanks,
> Rahul
Yes, it can be useful & there's nothing wrong with building in the .dtb for a
platform like pistachio. For the generic kernel however we put the various
device tree binaries into the FIT image so that the bootloader can pick out
the right one, so building them into the kernel is unnecessary.
Thanks,
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