[U-Boot] Revert "Ensure device tree DTS is compiled"

[Simon Glass]

Hi Tom, Masahiro,

On Sat, 9 Mar 2019 at 10:42, Tom Rini <trini at konsulko.com> wrote:
>
> On Sun, Mar 10, 2019 at 01:07:48AM +0900, Masahiro Yamada wrote:
> > Hi Tom,
> >
> >
> > On Sat, Mar 9, 2019 at 8:04 AM Tom Rini <trini at konsulko.com> wrote:
> > >
> > > On Thu, Mar 07, 2019 at 11:13:52PM +0900, Masahiro Yamada wrote:
> > >
> > > > This reverts commit 27cb7300ffda7a3f1581f0f5a2d3bfe59b97ad67.
> > > >
> > > > I am not sure if I correctly understood the log of commit 27cb7300ffda
> > > > ("Ensure device tree DTS is compiled"), but the code-diff looks like
> > > > it was trying to solve the missed re-compilation when .dts was modified.
> > > >
> > > > Recently, commit 2737dfe096b6 ("kbuild: make arch-dtbs target PHONY")
> > > > fixed the issue in a more correct and more complete way.
> > > >
> > > > Anyway, since the former commit, we see a clumsy log like this:
> > > >
> > > >   make[2]: 'arch/sandbox/dts/sandbox.dtb' is up to date
> > > >
> > > > So, let's revert it.
> > > >
> > > > Signed-off-by: Masahiro Yamada <yamada.masahiro at socionext.com>
> > >
> > > This causes tons of breakage like:
> > >        arm:  +   rpi_0_w
> > > +(rpi_0_w)
> > > +(rpi_0_w) Device Tree Source is not correctly specified.
> > > +(rpi_0_w) Please define 'CONFIG_DEFAULT_DEVICE_TREE'
> > > +(rpi_0_w) or build with 'DEVICE_TREE=<device_tree>' argument
> > > +(rpi_0_w) make[2]: *** [arch/arm/dts/bcm2835-rpi-zero-w.dtb] Error 1
> > > +(rpi_0_w) make[1]: *** [dts] Error 2
> > > +(rpi_0_w) make: *** [sub-make] Error 2
> > >
> >
> >
> > This is because arch/arm/dts/Makefile
> > has no entry for bcm2835-rpi-zero-w.dtb.
> >
> >
> >
> >
> > The following patch should fix the error
> >
> >
> > diff --git a/arch/arm/dts/Makefile b/arch/arm/dts/Makefile
> > index 2a040b2..5540f1b 100644
> > --- a/arch/arm/dts/Makefile
> > +++ b/arch/arm/dts/Makefile
> > @@ -582,6 +582,7 @@ dtb-$(CONFIG_ARCH_BCM283X) += \
> >         bcm2835-rpi-b-plus.dtb \
> >         bcm2835-rpi-b-rev2.dtb \
> >         bcm2835-rpi-b.dtb \
> > +       bcm2835-rpi-zero-w.dtb \
> >         bcm2836-rpi-2-b.dtb \
> >         bcm2837-rpi-3-b.dtb
> >
> >
> >
> >
> >
> > The reverted commit was hiding the issue.
> >
> > I believe DTB files should be explicitly associated
> > with CONFIG option in Makefile.
> > U-Boot used to work that way, and so does Linux.
> >
> >
> > I do not know how may boards are broken now, but
> > the right thing to do is to add dtb entries to Makefile,
> > the revert the bad commit.
>
> OK, that sounds good.  But it's a non-trivial number of boards to fix,
> so it's a real series to be put on the TODO list then.  Thanks for
> explaining!

If you are suggesting that we should have a separate CONFIG option for
every DT, I don't agree:

1. It adds more CONFIGs for no other purpose, or makes use of TARGET
configs which we try to avoid using
2. It reduces the testing of DT files for related builds. E.g. you can
change something in a common .dtsi file which works fine for one board
but breaks another, and you only find out when you build all the
boards.

Sorry if I have the wrong end of the stick.

Regards,
Simon