[PATCH v2 2/5] kbuild: Allow DTB overlays to built into .dtbo.S files

[Simon Glass]

On Wed, 10 Jul 2024 at 09:17, Rasmus Villemoes
<rasmus.villemoes at prevas.dk> wrote:
>
> [linux commit 941214a512d8, modified for U-Boot by removing the
> include of vmlinux.lds.h and replacing STRUCT_ALIGNMENT by 16.]
>
> DTB files can be built into the kernel by converting them to assembly
> files then assembling them into object files. We extend this here
> for DTB overlays with the .dtso extensions.
>
> We change the start and end delimiting tag prefix to make it clear that
> this data came from overlay files.
>
> Signed-off-by: Rasmus Villemoes <rasmus.villemoes at prevas.dk>
> ---
>  scripts/Makefile.lib | 20 +++++++++++++++++++-
>  1 file changed, 19 insertions(+), 1 deletion(-)
>

Reviewed-by: Simon Glass <sjg at chromium.org>


> diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
> index 3e68d5aa803..549c3619472 100644
> --- a/scripts/Makefile.lib
> +++ b/scripts/Makefile.lib
> @@ -305,7 +305,7 @@ endif
>  DTC_FLAGS += $(DTC_FLAGS_$(basetarget))
>
>  # Generate an assembly file to wrap the output of the device tree compiler
> -quiet_cmd_dt_S_dtb= DTB     $@
> +quiet_cmd_dt_S_dtb= DTBS    $@
>  # Modified for U-Boot
>  cmd_dt_S_dtb=                                          \
>  (                                                      \
> @@ -322,6 +322,24 @@ cmd_dt_S_dtb=                                              \
>  $(obj)/%.dtb.S: $(obj)/%.dtb
>         $(call cmd,dt_S_dtb)
>
> +# Generate an assembly file to wrap the output of the device tree compiler
> +quiet_cmd_dt_S_dtbo= DTBOS   $@
> +# Modified for U-Boot
> +cmd_dt_S_dtbo=                                         \
> +{                                                      \
> +       echo '.section .dtb.init.rodata,"a"';           \
> +       echo '.balign 16';                              \
> +       echo '.global __dtbo_$(subst -,_,$(*F))_begin'; \
> +       echo '__dtbo_$(subst -,_,$(*F))_begin:';        \
> +       echo '.incbin "$<" ';                           \
> +       echo '__dtbo_$(subst -,_,$(*F))_end:';          \
> +       echo '.global __dtbo_$(subst -,_,$(*F))_end';   \
> +       echo '.balign 16';                              \
> +} > $@
> +
> +$(obj)/%.dtbo.S: $(obj)/%.dtbo
> +       $(call cmd,dt_S_dtbo)
> +
>  ifeq ($(CONFIG_OF_LIBFDT_OVERLAY),y)
>  DTC_FLAGS += -@
>  endif
> --
> 2.45.2
>