[PATCH] kbuild: fix dependency of dtbs targets

[Rob Herring]

On Wed, Oct 25, 2017 at 12:40 AM, Masahiro Yamada
<yamada.masahiro at socionext.com> wrote:
> Hi.
>
>
> 2017-10-10 0:05 GMT+09:00 Russell King - ARM Linux <linux at armlinux.org.uk>:
>> On Wed, Oct 04, 2017 at 01:27:20PM +0900, Masahiro Yamada wrote:
>>> The target "dtbs" should depend on "scripts" because it needs to
>>> build dtc.  The "prepare" target is unneeded here.
>>
>> Looks fine for ARM, as the only thing the dtbs should depend on is
>> the kernel configuration (to decide which to build) and DT tooling.
>>
>> Acked-by: Russell King <rmk+kernel at armlinux.org.uk>
>>
>> --
>
>
> I found a potential issue on this
> because the default DTB install path depends on $(KERNELRELEASE).
>
>
> In top-level Makefile:
> export INSTALL_DTBS_PATH ?= $(INSTALL_PATH)/dtbs/$(KERNELRELEASE)
>
>
> The include/config/kernel.release is created by "prepare3" target.
>
> If the dependency on "parepare" is removed,
> it is possible to run "make dtbs" and "make dtbs_install"
> without creating include/config/kernel.release.
>
> So, the $(KERNELRELEASE) could be empty when installing DTB.
>
>
> Maybe, drop this patch, or reduce the dependency to "parepare3"?

I was doing some work to get dtb builds to work without depending on
$arch cross compiler and this patch fixes some of the issues. The
dtbs_install target has the prepare dependency, so that should be
sufficient and your patch should be fine. BTW, Based on prior
discussion on "ARM: kbuild: Fix forced rebuild after 'make dtbs'"
thread, prepare should not be needed just for $(KERNELRELEASE).

Rob