[PATCH v2] drm: ensure drm headers are self-contained and pass kernel-doc

[Jani Nikula]

On Tue, 02 Apr 2024, Jani Nikula <jani.nikula at intel.com> wrote:
> Ensure drm headers build, are self-contained, have header guards, and
> have no kernel-doc warnings, when CONFIG_DRM_HEADER_TEST=y.
>
> The mechanism follows similar patters used in i915, xe, and usr/include.
>
> To cover include/drm, we need to recurse there using the top level
> Kbuild and the new include/Kbuild files.

Masahiro, any input? Ack?

BR,
Jani.

>
> v2: make DRM_HEADER_TEST depend on DRM
>
> Suggested-by: Daniel Vetter <daniel at ffwll.ch>
> Cc: David Airlie <airlied at gmail.com>
> Cc: Daniel Vetter <daniel at ffwll.ch>
> Cc: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
> Cc: Maxime Ripard <mripard at kernel.org>
> Cc: Thomas Zimmermann <tzimmermann at suse.de>
> Cc: Masahiro Yamada <masahiroy at kernel.org>
> Acked-by: Thomas Zimmermann <tzimmermann at suse.de>
> Signed-off-by: Jani Nikula <jani.nikula at intel.com>
> ---
>  Kbuild                   |  1 +
>  drivers/gpu/drm/Kconfig  | 11 +++++++++++
>  drivers/gpu/drm/Makefile | 18 ++++++++++++++++++
>  include/Kbuild           |  1 +
>  include/drm/Makefile     | 18 ++++++++++++++++++
>  5 files changed, 49 insertions(+)
>  create mode 100644 include/Kbuild
>  create mode 100644 include/drm/Makefile
>
> diff --git a/Kbuild b/Kbuild
> index 464b34a08f51..f327ca86990c 100644
> --- a/Kbuild
> +++ b/Kbuild
> @@ -97,3 +97,4 @@ obj-$(CONFIG_SAMPLES)	+= samples/
>  obj-$(CONFIG_NET)	+= net/
>  obj-y			+= virt/
>  obj-y			+= $(ARCH_DRIVERS)
> +obj-$(CONFIG_DRM_HEADER_TEST)	+= include/
> diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
> index 3914aaf443a8..a388c4fda984 100644
> --- a/drivers/gpu/drm/Kconfig
> +++ b/drivers/gpu/drm/Kconfig
> @@ -431,3 +431,14 @@ config DRM_WERROR
>  	  this config option is disabled by default.
>  
>  	  If in doubt, say N.
> +
> +config DRM_HEADER_TEST
> +	bool "Ensure DRM headers are self-contained and pass kernel-doc"
> +	depends on DRM && EXPERT
> +	default n
> +	help
> +	  Ensure the DRM subsystem headers both under drivers/gpu/drm and
> +	  include/drm compile, are self-contained, have header guards, and have
> +	  no kernel-doc warnings.
> +
> +	  If in doubt, say N.
> diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
> index a73c04d2d7a3..6605d5686d01 100644
> --- a/drivers/gpu/drm/Makefile
> +++ b/drivers/gpu/drm/Makefile
> @@ -218,3 +218,21 @@ obj-y			+= solomon/
>  obj-$(CONFIG_DRM_SPRD) += sprd/
>  obj-$(CONFIG_DRM_LOONGSON) += loongson/
>  obj-$(CONFIG_DRM_POWERVR) += imagination/
> +
> +# Ensure drm headers are self-contained and pass kernel-doc
> +hdrtest-files := \
> +	$(shell cd $(srctree)/$(src) && find . -maxdepth 1 -name 'drm_*.h') \
> +	$(shell cd $(srctree)/$(src) && find display lib -name '*.h')
> +
> +always-$(CONFIG_DRM_HEADER_TEST) += \
> +	$(patsubst %.h,%.hdrtest, $(hdrtest-files))
> +
> +# Include the header twice to detect missing include guard.
> +quiet_cmd_hdrtest = HDRTEST $(patsubst %.hdrtest,%.h,$@)
> +      cmd_hdrtest = \
> +		$(CC) $(c_flags) -fsyntax-only -x c /dev/null -include $< -include $<; \
> +		$(srctree)/scripts/kernel-doc -none $(if $(CONFIG_DRM_WERROR),-Werror) $<; \
> +		touch $@
> +
> +$(obj)/%.hdrtest: $(src)/%.h FORCE
> +	$(call if_changed_dep,hdrtest)
> diff --git a/include/Kbuild b/include/Kbuild
> new file mode 100644
> index 000000000000..5e76a599e2dd
> --- /dev/null
> +++ b/include/Kbuild
> @@ -0,0 +1 @@
> +obj-$(CONFIG_DRM_HEADER_TEST)	+= drm/
> diff --git a/include/drm/Makefile b/include/drm/Makefile
> new file mode 100644
> index 000000000000..b9f391d7aadd
> --- /dev/null
> +++ b/include/drm/Makefile
> @@ -0,0 +1,18 @@
> +# SPDX-License-Identifier: GPL-2.0
> +
> +# Ensure drm headers are self-contained and pass kernel-doc
> +hdrtest-files := \
> +	$(shell cd $(srctree)/$(src) && find * -name '*.h' 2>/dev/null)
> +
> +always-$(CONFIG_DRM_HEADER_TEST) += \
> +	$(patsubst %.h,%.hdrtest, $(hdrtest-files))
> +
> +# Include the header twice to detect missing include guard.
> +quiet_cmd_hdrtest = HDRTEST $(patsubst %.hdrtest,%.h,$@)
> +      cmd_hdrtest = \
> +		$(CC) $(c_flags) -fsyntax-only -x c /dev/null -include $< -include $<; \
> +		$(srctree)/scripts/kernel-doc -none $(if $(CONFIG_DRM_WERROR),-Werror) $<; \
> +		touch $@
> +
> +$(obj)/%.hdrtest: $(src)/%.h FORCE
> +	$(call if_changed_dep,hdrtest)

-- 
Jani Nikula, Intel