Re: [PATCH v2] arm: Add Kconfig entry to select CONFIG_DTB_FILE

[Julien Grall <julien@xxxxxxx>]

Hi,

On 08/03/2021 13:59, Michal Orzel wrote:
> Currently in order to link existing DTB into Xen image
> we need to either specify option CONFIG_DTB_FILE on the
> command line or manually add it into .config.
> Add Kconfig entry: CONFIG_DTB_FILE to be able to
> provide the path to DTB we want to embed into Xen image.
> If no path provided - the dtb will not be embedded.
>
> Signed-off-by: Michal Orzel <michal.orzel@xxxxxxx>
> ---
>   xen/arch/arm/Makefile | 4 +---
>   xen/common/Kconfig    | 8 ++++++++
>   2 files changed, 9 insertions(+), 3 deletions(-)
>
> diff --git a/xen/arch/arm/Makefile b/xen/arch/arm/Makefile
> index 16e6523e2c..0f3e99d075 100644
> --- a/xen/arch/arm/Makefile
> +++ b/xen/arch/arm/Makefile
> @@ -68,7 +68,7 @@ extra-y += $(TARGET_SUBARCH)/head.o
>   
>   #obj-bin-y += ....o
>   
> -ifdef CONFIG_DTB_FILE
> +ifneq ($(CONFIG_DTB_FILE),"")
>   obj-y += dtb.o
>   AFLAGS-y += -DCONFIG_DTB_FILE=\"$(CONFIG_DTB_FILE)\"
>   endif
> @@ -137,8 +137,6 @@ asm-offsets.s: $(TARGET_SUBARCH)/asm-offsets.c
>   xen.lds: xen.lds.S
>         $(CPP) -P $(a_flags) -MQ $@ -o $@ $<
>   
> -dtb.o: $(CONFIG_DTB_FILE)
> -
Why is this dropped?

>   .PHONY: clean
>   clean::
>         rm -f asm-offsets.s xen.lds
> diff --git a/xen/common/Kconfig b/xen/common/Kconfig
> index eb953d171e..a4c8d09edf 100644
> --- a/xen/common/Kconfig
> +++ b/xen/common/Kconfig
> @@ -400,6 +400,14 @@ config DOM0_MEM
>   
>   	  Leave empty if you are not sure what to specify.
>   
> +config DTB_FILE
May I ask why is this add in common/Kconfig rather than arm/Kconfig?

> +       string "Absolute path to device tree blob"
> +       depends on ARM
If this stay in common Kconfig, shouldn't this be gated with 
HAS_DEVICE_TREE?
> +       ---help---
> +         When using a bootloader that has no device tree support or when there
> +         is no bootloader at all, use this option to specify the absolute path
> +         to a device tree that will be linked directly inside Xen binary.
> +
>   config TRACEBUFFER
>         bool "Enable tracing infrastructure" if EXPERT
>         default y
Cheers,

--
Julien Grall