[Buildroot] [PATCH 2/2] board/raspberrypi: add post-image option for VC4 overlay.

[Peter Seiderer <ps.report@gmx.net>]

Hello Charlie,

On Tue, 10 Mar 2020 11:22:27 +0000, Charlie Turner <cturner@igalia.com> wrote:

> It is often necessary to add a device tree overlay for the VC4 V3D
> driver. On a Raspberry Pi 4 for example, if you enable the Gallium VC4
> Mesa driver, you must add dtoverlay=vc4-fkms-v3d to the kernel command
> line for it to work correctly. There are times when adding vc4-kms-v3d
> is also required. This option allows post-image scripts to add either
> option conveniently depending on their specific configuration.

There where already some attempts for this (or similar) feature enhancement
(see [1], [2]), but maybe it is more stuff for an real custom setup (to keep
the buildroot minimal approach)?

>
> Signed-off-by: Charlie Turner <cturner@igalia.com>
> ---
>  board/raspberrypi/post-image.sh | 14 +++++++++++++-
>  1 file changed, 13 insertions(+), 1 deletion(-)
>
> diff --git a/board/raspberrypi/post-image.sh b/board/raspberrypi/post-image.sh
> index 9dbd98ef9b..4ffda4bf49 100755
> --- a/board/raspberrypi/post-image.sh
> +++ b/board/raspberrypi/post-image.sh
> @@ -11,7 +11,7 @@ for arg in "$@"
>  do
>  	case "${arg}" in
>  		--add-miniuart-bt-overlay)
> -		if ! grep -qE '^dtoverlay=' "${BINARIES_DIR}/rpi-firmware/config.txt"; then
> +		if ! grep -qE '^dtoverlay=miniuart-bt' "${BINARIES_DIR}/rpi-firmware/config.txt"; then
>  			echo "Adding 'dtoverlay=miniuart-bt' to config.txt (fixes ttyAMA0 serial console)."
>  			cat << __EOF__ >> "${BINARIES_DIR}/rpi-firmware/config.txt"
>
> @@ -36,6 +36,18 @@ __EOF__
>  		gpu_mem="${arg:2}"
>  		sed -e "/^${gpu_mem%=*}=/s,=.*,=${gpu_mem##*=}," -i "${BINARIES_DIR}/rpi-firmware/config.txt"
>  		;;
> +		--vc4-modesetting-overlay=*)

Call the option simple add-vc4-fkms-v3d-overlay for 'vc4-fkms-v3d.dtb', or make
it completely generic?

> +		overlay=${arg##*=}
> +		if ! grep -qE "^dtoverlay=vc4-.*-v3d" "${BINARIES_DIR}/rpi-firmware/config.txt"; then
> +			echo "Adding 'dtoverlay=vc4-${overlay}-v3d' to config.txt."
> +			cat << __EOF__ >> "${BINARIES_DIR}/rpi-firmware/config.txt"
> +
> +dtoverlay=vc4-${overlay}-v3d
> +__EOF__
> +		else
> +			sed -e "/^dtoverlay=vc4-.*-v3d/s,=.*,=vc4-${overlay}-v3d," -i "${BINARIES_DIR}/rpi-firmware/config.txt"
> +		fi
> +		;;
>  	esac
>
>  done

Regards,
Peter

[1] https://patchwork.ozlabs.org/patch/1007728
[2] http://lists.busybox.net/pipermail/buildroot/2019-February/243941.html