A build pattern to handle out of tree dtbs is to copy the .dts file into
the kernel source tree and run `make myboard.dtb`. This is supported by
the wildcard %.dtb rule in the Makefile but recent changes to split the
dtb handling out of scripts/Makefile.build stopped this from working.
Restore this functionality by looking for the relevant file extensions
in $(MAKECMDGOALS) instead of $(targets).

Fixes: e7e2941300d2 ("kbuild: split device tree build rules into scripts/Makefile.dtbs")
Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
---

Notes:
    This seems to address the problem building out of tree dtbs. I think it
    is correct because as far as I can tell nothing will pull .dtb and
    friends into $(targets) and we explicity check for a non-empty $(dtb-y).

 scripts/Makefile.build | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index 8f423a1faf50..58404c1c5eda 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -449,7 +449,7 @@ ifneq ($(userprogs),)
 include $(srctree)/scripts/Makefile.userprogs
 endif
 
-ifneq ($(need-dtbslist)$(dtb-y)$(dtb-)$(filter %.dtb %.dtb.o %.dtbo.o,$(targets)),)
+ifneq ($(need-dtbslist)$(dtb-y)$(dtb-)$(filter %.dtb %.dtb.o %.dtbo.o,$(MAKECMDGOALS)),)
 include $(srctree)/scripts/Makefile.dtbs
 endif
 
-- 
2.47.0

Hi Chris,

kernel test robot noticed the following build errors:

[auto build test ERROR on masahiroy-kbuild/for-next]
[also build test ERROR on masahiroy-kbuild/fixes linus/master v6.12-rc3 next-20241016]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Chris-Packham/kbuild-Restore-the-ability-to-build-out-of-tree-dtbs/20241016-053034
base:   https://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild.git for-next
patch link:    https://lore.kernel.org/r/20241015212830.3899891-1-chris.packham%40alliedtelesis.co.nz
patch subject: [PATCH] kbuild: Restore the ability to build out of tree dtbs
:::::: branch date: 14 hours ago
:::::: commit date: 14 hours ago
config: openrisc-defconfig (https://download.01.org/0day-ci/archive/20241016/202410161857.7osnf6AX-lkp@intel.com/config)
compiler: or1k-linux-gcc (GCC) 14.1.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20241016/202410161857.7osnf6AX-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/r/202410161857.7osnf6AX-lkp@intel.com/

All errors (new ones prefixed by >>):

>> make[5]: *** No rule to make target 'arch/openrisc/boot/dts/or1ksim.dtb.o', needed by 'arch/openrisc/boot/dts/built-in.a'.
   make[5]: Target 'arch/openrisc/boot/dts/' not remade because of errors.

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki