On Fri, Sep 7, 2018 at 5:33 AM Masahiro Yamada
[off-list ref] wrote:

2018-09-06 8:53 GMT+09:00 Rob Herring [off-list ref]:

quoted

There is nothing arch specific about building dtb files other than their
location under /arch/*/boot/dts/. Keeping each arch aligned is a pain.
The dependencies and supported targets are all slightly different.
Also, a cross-compiler for each arch is needed, but really the host
compiler preprocessor is perfectly fine for building dtbs. Move the
build rules to a common location and remove the arch specific ones. This
is done in a single step to avoid warnings about overriding rules.

The build dependencies had been a mixture of 'scripts' and/or 'prepare'.
These pull in several dependencies some of which need a target compiler
(specifically devicetable-offsets.h) and aren't needed to build dtbs.
All that is really needed is dtc, so adjust the dependencies to only be
dtc.

This change enables support 'dtbs_install' on some arches which were
missing the target.

Cc: Masahiro Yamada <redacted>
Cc: Michal Marek <redacted>
Cc: Vineet Gupta <redacted>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <redacted>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Ralf Baechle <redacted>
Cc: Paul Burton <redacted>
Cc: James Hogan <jhogan@kernel.org>
Cc: Ley Foon Tan <redacted>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <redacted>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Chris Zankel <chris@zankel.net>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: linux-kbuild@vger.kernel.org
Cc: linux-snps-arc@lists.infradead.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: uclinux-h8-devel@lists.sourceforge.jp
Cc: linux-mips@linux-mips.org
Cc: nios2-dev@lists.rocketboards.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-xtensa@linux-xtensa.org
Signed-off-by: Rob Herring <robh@kernel.org>
---
Please ack so I can take the whole series via the DT tree.

v2:
 - Fix $arch/boot/dts path check for out of tree builds
 - Fix dtc dependency for building built-in dtbs
 - Fix microblaze built-in dtb building

This breaks parallel building
because two threads could descend into scripts/dtc
at the same time.

'all' depends on both 'scripts' and 'dtc'.

* 'scripts' target -- descends into scripts/, then scripts/dtc
* 'dtc' target     -- descents into scripts/dtc directly

Any suggestions for how to fix given the problem with depending on
scripts? I suppose I could make scripts depend on dtc instead, but I'd
be back to needing to fix cleaning. Or I could just skip removing the
cross compiler dependency for now.

Rob