Intro

⚠️ Help and pull requests are welcome ⚠️

The purpose of this repo is to use Buildroot to produce images that run a Kivy app. Currently Raspberry Pi2 and Intel Stick STK1AW32SC have been tested and both are working.

See the section below "Extra work on Raspberry Pi2" for other challenges to resolve.

This repo is meant to be used implementing Buildroot's BR2_EXTERNAL tree mechanism.

Quick setup:

Besides using this repo in your existing Buildroot installation using the external mechanism, there is also the option to use this docker-buildroot repo that provides a fast and convenient way to start working right away.

Those are the instructions for the later case:

1. Get a clone of docker-buildroot:

git clone https://github.com/vidalastudillo/docker-buildroot

2. Get a clone of this repo to be placed at the folder externals/kivy:

git clone https://github.com/MrMauro/buildroot_external-kivy externals/kivy

3. Build the Docker image:

docker build -t "advancedclimatesystems/buildroot" .

4. Create a data-only container:

docker run -i --name buildroot_kivy_output advancedclimatesystems/buildroot /bin/echo "Just Kivy data from Buildroot."

This container has 2 volumes at /root/buildroot/dl and /buildroot_kivy_output. Buildroot downloads all data to the first volume, the last volume is used as build cache, cross compiler and build results.

5. Setup the new external folder and load the default configuration:

./scripts/run.sh make BR2_EXTERNAL=/root/buildroot/externals/kivy menuconfig

For Raspberry Pi 2:

./scripts/run.sh make rpi2_defconfig

For Intel Stick:

./scripts/run.sh make intelstick_defconfig

These are the two relevant folders on your host:

• external/kivy: the new external folder with the configs and other related files.
• images: with your valuable results.

Also, the target folder is provided just to ease checking the building process.

Buildroot usage

A small script has been provided to make using the container a little easier. It's located at the folder scripts/run.sh.

Then you can use usual commands like this:

./scripts/run.sh make menuconfig
./scripts/run.sh make all

Use of the images produced

The current produced images are yet to be polished.

• SSH access as been enabled for user root with password 1
• There is a folder kivyapp that have some very simple hello world test.

On the Intel Stick version, the X11 is implemented. Upon start, a black screen is displayed on the monitor. It is necessary to login via SSH and issue:

shell~~ ~~startx~~ ~~

The monitor will now display a couple of windows. On the labeled xterm type

shell~~ python simpletest.py ~~

That should display the hello world test.

About the Kivy Package for Buildroot

Details about the purpose and status of this Kivy Package can be found at package/python-kivy/.

Extra work with the Raspberry Pi2

⚠️ This is still work in progress ⚠️

The next content has been based on this great post that shows how to build Kivy running on a RP2 by evgueni with the idea to extend the use of the image produced for the Pi2.

The shell commands here are based on the run.sh script in case the docker-buildroot is used. Otherwise in a normal Buildroot installation, those are meant to be issued without ./scripts/run.sh.

myrpi2_defconfig

The basic image:

• Starting point.

./scripts/run.sh make clean all
./scripts/run.sh make myrpi2_defconfig
./scripts/run.sh make

myrpi2_splash_defconfig

(Not working yet, splash does not work)

New from previous configuration myrpi2_defconfig:

• Splash screen, means of customizing image assembly - used to effect "silent" boot

Modified from original post:

• Modified post-image.sh from the buildroot original.
• Modified cmdline.txt from the post original, to include missing splash.
• Changed kernel version: BR2_PACKAGE_HOST_LINUX_HEADERS_CUSTOM_5_10=y BR2_LINUX_KERNEL_CUSTOM_TARBALL_LOCATION="$(call github,raspberrypi,linux,581049d718caf95f5feb00607ac748d5841cf27c)/linux-581049d718caf95f5feb00607ac748d5841cf27c.tar.gz"
• Added (Build failed as bootcode.bin was not created): BR2_PACKAGE_RPI_FIRMWARE_BOOTCODE_BIN=y BR2_PACKAGE_RPI_FIRMWARE_VARIANT_PI=y

./scripts/run.sh make clean all
./scripts/run.sh make myrpi2_splash_defconfig
./scripts/run.sh make

myrpi2_splash_kivy_defconfig

(splash does not work, yet)

New from previous configuration myrpi2_splash_defconfig:

• THUMB2 instruction set and MUSL LIBC, intention being to reduce image size and speed up cold boot
• /dev creation with eudev
• root login via SSH (pwd "raspberry")
• python3 + kivy

Modified from original post:

• Same from configuration myrpi2_splash_defconfig

./scripts/run.sh make clean all
./scripts/run.sh make myrpi2_splash_kivy_defconfig
./scripts/run.sh make

myrpi2_kivy_rofs_defconfig

(splash does not work, yet) (kivy app does not work, yet. No logs. It may be related to i2c-dev not present on etc/modules )

New from previous configuration myrpi2_splash_kivy_defconfig:

• read-only file system
• usb storage FAT and NTFS
• h/w pwm
• quadrature encoder input
• I2C, SPI

Modified from original post:

• Same from configuration myrpi2_splash_kivy_defconfig

./scripts/run.sh make clean all
./scripts/run.sh make myrpi2_kivy_rofs_defconfig
./scripts/run.sh make

Saving configs

A modified configuration can be saved using something like this (replacing the text 'mycustom'):

./scripts/run.sh make BR2_DEFCONFIG=/root/buildroot/externals/kivy/configs/mycustom_defconfig savedefconfig

License

This software is licensed under MIT License.

© 2022 Mauricio Vidal.