Is it possible to pass extra device-tree include directory?

[Ahmad Fatoum]

Hello,

On 6/26/20 9:12 AM, Denis Osterland-Heim wrote:
> Hi Sascha,
> 
> which implementation variant would you prefer?
> 
> 1) target specific flags
> diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
> index 9aa8be535f30..6f341a6e3e86 100644
> --- a/scripts/Makefile.lib
> +++ b/scripts/Makefile.lib
> @@ -164,6 +164,7 @@ dtc_cpp_flags  = -Wp,-MD,$(depfile).pre -nostdinc                        \
>  		 -I$(srctree)/dts/include                                \
>  		 -I$(srctree)/include                                    \
>  		 -I$(srctree)/dts/src/                                   \
> +		 $(DTC_CPP_FLAGS_$(basetarget).dtb)                      \
>  		 -undef -D__DTS__
>  
>  ifdef CONFIG_BOOTM_FITIMAGE_PUBKEY
> 
> with something like this in arch/arm/dts/Makefile:
> DTC_CPP_FLAGS_my-board-name.dtb := -I${PTXDIST_PLATFORMCONFIGDIR}/dts
> lwl-dtb-$(CONFIG_MACH_MY_BOARD_NAME) += my-board-name.dtb.o
> 
> So we can clearly state that the device-tree is out of barebox tree.

Do you really want to modify your bootloader every time you touch the kernel
device tree? Projects I am involved in, have a local patch to dts/ that imports
the BSP device trees and then extends then in arch/$ARCH/dts. The dts/ device
trees are updated along with bootloader update, when I can retest that the
kernel modifications didn't break something unexpected. The kernel device tree
changes more often than that.

I don't think passing arbitrary options to dtc is something we should encourage.

Cheers
Ahmad

> 
> 
> 2) add EXTRA_DTC_CPP_FLAGS to Makefile.lib, to pass it to make
> 
> 
> 3) add $(patsubst "%",%,$(CONFIG_DTC_CPP_FLAGS)) to Makefile.lib, and a Kconfig option
> 
> diff --git a/common/Kconfig b/common/Kconfig
> index 02ef3631e04b..074f25aa6b7f 100644
> --- a/common/Kconfig
> +++ b/common/Kconfig
> @@ -1347,3 +1347,6 @@ config DDR_SPD
>  
>  config HAVE_ARCH_KASAN
>         bool
> +
> +config DTC_CPP_FLAGS
> +       string "extra dtc-cpp flags"
> 
> 
> Regards Denis
> 
> Am Freitag, den 26.06.2020, 06:49 +0200 schrieb Sascha Hauer:
>> Hi Denis,
>>
>> On Mon, Jun 22, 2020 at 07:42:11AM +0000, Denis Osterland-Heim wrote:
>>> Hi,
>>>
>>> is it possible to pass extra device-tree include directory?
>>> For instance "${PTXDIST_PLATFORMCONFIGDIR}/dts" to have a out-of-tree dts only in one place?
>>
>> I am not aware of any possibility doing this currently.
>>
>> Regards,
>>  Sascha
>>
> 
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