[Buildroot] [PATCH v2] raspberrypi3: fix serial console (load pi3-miniuart-bt overlay)

[Oscar Gomez Fuente]

Hi Peter Seiderer,


What's the difference between enabling pi3-miniuart-bt instead of
pi3-disable-bt?

With pi3-disable-bt enables it works fine the serial console on (14 [TxD] &
15 [RxD] pins).


Best regards.

Oscar Gomez Fuente.

On 2 May 2016 at 22:25, Peter Seiderer <ps.report at gmx.net> wrote:

> - enable BR2_PACKAGE_RPI_FIRMWARE_INSTALL_DTB_OVERLAYS in
> raspberrypi3_defconfig
> - add copy of rpi-firmware/overlays directory to boot partition in
> genimage-raspberrypi3.cfg
> - enhance post-image.sh script to add 'dtoverlay=pi3-miniuart-bt' on
> request
> - add BR2_ROOTFS_POST_SCRIPT_ARGS="--add-pi3-miniuart-bt-overlay" in
> raspberrypi3_defconfig
>
> Signed-off-by: Peter Seiderer <ps.report at gmx.net>
> ---
> Changes v1 --> v2:
>   - use pi3-miniuart-bt instead of pi3-disable-bt
>   - fix post-image.sh to add overlay lines only once
>   - add overlay description (and alternative solution) to readme.txt
> ---
>  board/raspberrypi/genimage-raspberrypi3.cfg |  1 +
>  board/raspberrypi/post-image.sh             | 13 +++++++++++++
>  board/raspberrypi/readme.txt                |  8 +++++++-
>  configs/raspberrypi3_defconfig              |  3 ++-
>  4 files changed, 23 insertions(+), 2 deletions(-)
>
> diff --git a/board/raspberrypi/genimage-raspberrypi3.cfg
> b/board/raspberrypi/genimage-raspberrypi3.cfg
> index 7ba89c5..baab0c4 100644
> --- a/board/raspberrypi/genimage-raspberrypi3.cfg
> +++ b/board/raspberrypi/genimage-raspberrypi3.cfg
> @@ -7,6 +7,7 @@ image boot.vfat {
>        "rpi-firmware/config.txt",
>        "rpi-firmware/fixup.dat",
>        "rpi-firmware/start.elf",
> +      "rpi-firmware/overlays",
>        "kernel-marked/zImage"
>      }
>    }
> diff --git a/board/raspberrypi/post-image.sh
> b/board/raspberrypi/post-image.sh
> index 73ffd65..c009752 100755
> --- a/board/raspberrypi/post-image.sh
> +++ b/board/raspberrypi/post-image.sh
> @@ -5,6 +5,19 @@ BOARD_NAME="$(basename ${BOARD_DIR})"
>  GENIMAGE_CFG="${BOARD_DIR}/genimage-${BOARD_NAME}.cfg"
>  GENIMAGE_TMP="${BUILD_DIR}/genimage.tmp"
>
> +case "${2}" in
> +       --add-pi3-miniuart-bt-overlay)
> +       if ! grep -qE '^dtoverlay='
> "${BINARIES_DIR}/rpi-firmware/config.txt"; then
> +               echo "Adding 'dtoverlay=pi3-miniuart-bt' to config.txt
> (fixes ttyAMA0 serial console)."
> +               cat << __EOF__ >> "${BINARIES_DIR}/rpi-firmware/config.txt"
> +
> +# fixes rpi3 ttyAMA0 serial console
> +dtoverlay=pi3-miniuart-bt
> +__EOF__
> +       fi
> +       ;;
> +esac
> +
>  # Mark the kernel as DT-enabled
>  mkdir -p "${BINARIES_DIR}/kernel-marked"
>  ${HOST_DIR}/usr/bin/mkknlimg "${BINARIES_DIR}/zImage" \
> diff --git a/board/raspberrypi/readme.txt b/board/raspberrypi/readme.txt
> index a170f8f..03178ff 100644
> --- a/board/raspberrypi/readme.txt
> +++ b/board/raspberrypi/readme.txt
> @@ -60,7 +60,8 @@ After building, you should obtain this tree:
>      |   +-- cmdline.txt
>      |   +-- config.txt
>      |   +-- fixup.dat
> -    |   `-- start.elf
> +    |   +-- start.elf
> +    |   `-- overlays/               [3]
>      +-- sdcard.img
>      `-- zImage
>
> @@ -69,6 +70,11 @@ After building, you should obtain this tree:
>
>  [2] This is the mkknlimg DT-marked kernel.
>
> +[3] Only for the Raspberry Pi 3 Model (overlay pi3-miniuart-bt is needed
> +    to enable the RPi3 serial console otherwise occupied by the bluetooth
> +    chip). Alternative would be to disable the serial console in
> cmdline.txt
> +    and /etc/inittab.
> +
>  How to write the SD card
>  ========================
>
> diff --git a/configs/raspberrypi3_defconfig
> b/configs/raspberrypi3_defconfig
> index 4eb5333..8600cd8 100644
> --- a/configs/raspberrypi3_defconfig
> +++ b/configs/raspberrypi3_defconfig
> @@ -21,7 +21,7 @@ BR2_LINUX_KERNEL_DTS_SUPPORT=y
>  BR2_LINUX_KERNEL_INTREE_DTS_NAME="bcm2710-rpi-3-b"
>
>  BR2_PACKAGE_RPI_FIRMWARE=y
> -# BR2_PACKAGE_RPI_FIRMWARE_INSTALL_DTB_OVERLAYS is not set
> +BR2_PACKAGE_RPI_FIRMWARE_INSTALL_DTB_OVERLAYS=y
>
>  # Required tools to create the SD image
>  BR2_PACKAGE_HOST_DOSFSTOOLS=y
> @@ -34,3 +34,4 @@ BR2_TARGET_ROOTFS_EXT2_4=y
>  # BR2_TARGET_ROOTFS_TAR is not set
>  BR2_ROOTFS_POST_BUILD_SCRIPT="board/raspberrypi3/post-build.sh"
>  BR2_ROOTFS_POST_IMAGE_SCRIPT="board/raspberrypi3/post-image.sh"
> +BR2_ROOTFS_POST_SCRIPT_ARGS="--add-pi3-miniuart-bt-overlay"
> --
> 2.8.1
>
>
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