byteDEVKIT (Yocto 2.7)

Image

Where do you get the SD card image?

Device Yocto Version Download Checksum (SHA256)
byteDEVKIT Yocto 2.7 flashlayout_bytesatwork-minimal-image_FlashLayout_sdcard_stm32mp157c-bytedevkit.raw.gz 7e62644473c21d200603b52d0080894a0ccfd950dd4a2f3c7df2b14753566de8

Hint

Updating from an older image? You can update your older image by using: apt-get update and apt-get upgrade.

  1. check for new version in the table above
  2. edit /etc/apt/sources.list and point to the new package feed
  3. run apt-get update; apt-get upgrade

As the yocto framework is based on several packages from various projects or suppliers, it is not guaranteed that an incremental upgrade by apt-get upgrade works automatically. Some manual adjustments might be needed.


How do you flash the image?

Attention

  • You need a microSD card with at least 8GB capacity.
  • All existing data on the microSD card will be lost.
  • Do not format the microSD card before flashing.

Windows

  1. Unzip the file flashlayout_bytesatwork-minimal-image_FlashLayout_sdcard_stm32mp157c-bytedevkit.raw.gz (e.g. with 7-zip)
  2. Write the resulting file to the microSD card with a tool like Roadkils Disk Image

Linux

gunzip -c flashlayout_bytesatwork-minimal-image_FlashLayout_sdcard_stm32mp157c-bytedevkit.raw.gz | dd of=/dev/mmcblk<X> bs=8M conv=fdatasync status=progress

How do you build an image?

Use repo to download all necessary repositories:

$ mkdir -p ~/workdir/bytedevkit/2.7; cd ~/workdir/bytedevkit/2.7
$ repo init -u https://github.com/bytesatwork/bsp-platform-st.git -b warrior
$ repo sync

If those commands are completed successfully, the following command will set up a Yocto Project environment for byteDEVKIT:

$ cd ~/workdir/bytedevkit/2.7
$ MACHINE=bytedevkit DISTRO=poky-bytesatwork EULA=1 . setup-environment build

The final command builds the development image:

$ cd $BUILDDIR
$ bitbake devbase-image-bytesatwork

The output is found in:

~/workdir/bytedevkit/2.7/build/tmp/deploy/images/bytedevkit

How to modify the image

The image recipes can be found in ~/workdir/<machine name>/<yocto version>/sources/meta-bytesatwork/recipes-core/images

This is relative to where you started the repo command to fetch all the sources.

Edit the minimal-image recipe bytesatwork-minimal-image.bb

Add the desired software-package to IMAGE_INSTALL variable, for example add net-tools to bytesatwork-minimal-image.bb

Rebuild the image by:

$ cd ~/workdir/<machine name>/<yocto version>
$ MACHINE=<machine name> DISTRO=poky-bytesatwork EULA=1 . setup-environment build
$ bitbake bytesatwork-minimal-image

How to rename the image

If you want to rename or copy an image, simply rename or copy the image recipe by:

$ cd ~/workdir/<machine name>/<yocto version>/build/tmp/deploy/images/<machine name>
$ cp bytesatwork-minimal-image.bb customer-example-image.bb

Troubleshooting

  • Image size is to small

    If you encounter that your image size is to small to install additional software, please have a look at the IMAGE_ROOTFS_SIZE variable under ~/workdir/<machine-name>/<yocto version>/sources/meta-bytesatwork/recipes-core/images/bytesatwork-minimal-image.bb. Increase the size if necessary.


Toolchain

Where do you get the toolchain?

Device Yocto Version Download Checksum (SHA256)
byteDEVKIT Yocto 2.7 poky-bytesatwork-glibc-x86_64-devbase-image-bytesatwork-cortexa7t2hf-neon-vfpv4-bytedevkit-toolchain-2.7.1.sh 61896873ac7c75ac711a0b8e439ded6721d1a794deec26b4903178efbf51d307

How do you install the toolchain?

Simply download the toolchain and execute the downloaded file, which is a self-extracting shell script.

Hint

If you encounter problems when trying to install the toolchain, make sure the downloaded toolchain is executable. Run chmod +x /<path>/<toolchain-file>.sh to make it executable.

Important

The following tools need to be installed on your development system:
  • xz (Debian package: xz-utils)
  • python (any version)
  • gcc

How do you use the toolchain?

Source the installed toolchain:

source /opt/poky-bytesatwork/3.0.3/environment-setup-cortexa7t2hf-neon-vfpv4-poky-linux-gnueabi

Check if Cross-compiler is available in environment:

echo $CC

You should see the following output:

arm-poky-linux-gnueabi-gcc -mthumb -mfpu=neon-vfpv4 -mfloat-abi=hard -mcpu=cortex-a7 -fstack-protector-strong -D_FORTIFY_SOURCE=2 -Wformat -Wformat-security -Werror=format-security --sysroot=/opt/poky-bytesatwork/3.0.3/sysroots/cortexa7t2hf-neon-vfpv4-poky-linux-gnueabi

Crosscompile the source code, e.g. by:

$CC helloworld.c -o helloworld

Check generated binary:

file helloworld

The output that is shown in prompt afterwards:

helloworld: ELF 32-bit LSB pie executable, ARM, EABI5 version 1

How to bring your binary to the target?

  1. Connect the embedded device’s ethernet to your LAN
  2. Determine the embedded target IP address by ip addr show
https://www.bytesatwork.io/wp-content/uploads/2020/05/ip_addr_show_28.png
  1. Copy your binary, e.g. helloworld to the target by scp helloworld root@<ip address of target>:/tmp
https://www.bytesatwork.io/wp-content/uploads/2020/05/scp2.png
  1. Run chmod +x on the target to make your binary executable: chmod +x /<path>/<binary name>
  2. Run your binary on the target: /<path>/<binary name>

How do you build a toolchain?

$ cd ~/workdir/bytedevkit/2.7
$ repo init -u https://github.com/bytesatwork/bsp-platform-st.git -b warrior
$ repo sync

If those commands are completed successfully, the following command will set up a Yocto Project environment for byteDEVKIT:

$ ~/workdir/bytedevkit/2.7
$ MACHINE=bytedevkit DISTRO=poky-bytesatwork EULA=1 . setup-environment build

The final command builds an installable toolchain:

$ cd $BUILDDIR
$ bitbake devbase-image-bytesatwork -c populate_sdk

The toolchain is located under:

~/workdir/bytedevkit/2.7/build/tmp/deploy/sdk

How to modify your toolchain

Currently the bytesatwork toolchain is generated out of the bytesatwork-minimal-image recipe. If you want to add additional libraries and development headers to customize the toolchain, you need to modify the bytesatwork-minimal-image recipe. It can be found under ~/workdir/<machine name>/<yocto version>/sources/meta-bytesatwork/recipes-core/images

For example if you want to develop your own ftp client and you need libftp and the corresponding header files, edit the recipe bytesatwork-minimal-image.bb and add ftplib to the IMAGE_INSTALL variable.

This will provide the ftplib libraries and development headers in the toolchain. After adding additional software components, the toolchain needs to be rebuilt by:

$ cd ~/workdir/<machine name>/<yocto version>
$ MACHINE=<machine> DISTRO=poky-bytesatwork EULA=1 . setup-environment build
$ bitbake bytesatwork-minimal-image -c populate_sdk

The newely generated toolchain will be available under:

~/workdir/<machine name>/<yocto version>/build/tmp/deploy/sdk

For additional information, please visit: https://www.yoctoproject.org/docs/3.0.3/overview-manual/overview-manual.html#cross-development-toolchain-generation


Kernel

Download the Linux Kernel

Device Branch git URL
byteDEVKIT baw-v4.19-stm32mp https://github.com/bytesatwork/linux-stm32mp.git

Build the Linux Kernel

For both targets, an ARM toolchain is necessary. You can use the provided toolchain from Where do you get the toolchain? or any compatible toolchain (e.g. from your distribution)

Important

The following tools need to be installed on your development system:
  • git
  • make
  • bc

Note

The following instructions assume, you installed the provided toolchain for the respective target.

Important

The following tools need to be installed on your development system:
  • OpenSSL headers (Debian package: libssl-dev)
  • depmod (Debian package: kmod)
  1. Download kernel sources

    Download the appropriate kernel from Download the Linux Kernel.

  2. Source toolchain

    source /opt/poky-bytesatwork/3.0.3/environment-setup-cortexa7t2hf-neon-vfpv4-poky-linux-gnueabi
    
  3. Create defconfig

    make multi_v7_defconfig
    scripts/kconfig/merge_config.sh -m -r .config arch/arm/configs/fragment-*
    make olddefconfig
    
  4. Build Linux kernel

    make LOADADDR=0xC2000040 -j `nproc` uImage stm32mp157c-bytedevkit-v1-1.dtb modules
    
  5. Install kernel and device tree

    To use the newly created kernel, device tree and/or module, the necessary files need to be installed on the target. This can be done either via Ethernet (e.g. scp) or by copying the files to the SD card.

    Note

    For scp installation: Don’t forget to mount /boot on the target.

    File Target path Target partition
    arch/arm/boot/uImage /boot/uImage /dev/mmcblk0p4
    arch/arm/boot/dts/stm32mp157c-bytedevkit-v1-1.dtb /boot/stm32mp157c-bytedevkit.dtb /dev/mmcblk0p4

    Note

    After installing a new kernel, it often fails to load modules, as the _signature_ of the kernel changed and it fails to find its corresponding modules folder. This issue can often be resolved with a symlink:

    ln -s /lib/modules/<EXISTING FOLDER> /lib/modules/`uname -r`
    

    Otherwise, please follow the instructions to copy the kernel modules

  6. Install kernel modules

    To copy all available modules to the target, it’s best to deploy them locally first and then copy all modules to the target.

    mkdir /tmp/bytedevkit
    make INSTALL_MOD_PATH=/tmp/bytedevkit modules_install
    
Now you can copy the content of the folder /tmp/bytedevkit into the target’s root folder (/) which is partition /dev/mmcblk0p5.
https://www.bytesatwork.io/wp-content/uploads/2020/04/Bildschirmfoto-2020-04-20-um-19.41.44.jpg