Building an Image with Yocto

Introduction

This article provides step-by-step instructions for building a Linux image with TechNexion's Yocto BSP, which supports the i.MX series of processors.

System Requirements

Building an image from source with Yocto requires a host with the following:

• 8GB RAM (more is better)
• 4 Core processor
• 200 GB storage

If less memory is used, then some additional swap space may be needed. Inadequate memory may result slow builds and random build errors.

In addition, the host must be connected to a network and have access to the Internet so that all source code and tools may be downloaded.

Set up build environment on host PC:

The build environment is tested under Ubuntu 18.04 and Ubuntu 20.04.

Install required packages:

# First update the host package list
sudo apt-get update

# Install necessary packages
sudo apt-get install gawk wget git git-core diffstat unzip texinfo gcc-multilib build-essential \
chrpath socat cpio python python3 python3-pip python3-pexpect \
python3-git python3-jinja2 libegl1-mesa pylint3 rsync bc bison \
xz-utils debianutils iputils-ping libsdl1.2-dev xterm \
language-pack-en coreutils texi2html file docbook-utils \
python-pysqlite2 help2man desktop-file-utils \
libgl1-mesa-dev libglu1-mesa-dev mercurial autoconf automake \
groff curl lzop asciidoc u-boot-tools libreoffice-writer \
sshpass ssh-askpass zip xz-utils kpartx vim screen

Install the Repo Tool

There are many respositories required. Google's repo tool is used to manage this.

mkdir ~/bin
curl http://commondatastorage.googleapis.com/git-repo-downloads/repo > ~/bin/repo
chmod a+x ~/bin/repo

Download the BSP source

PATH=${PATH}:~/bin
mkdir edm_yocto
cd edm_yocto

Next, initialize the repositories based on the release you wish to build:

Fetch the source code:

repo sync -j8

Create build environment

There are several options regarding the build environment that you can use.

Prepare WIFI/BT firmware

You may optionally choose to add WIFI/BT firmware to the build. To do this, add the argument "WIFI_FIRMWARE=y" in during BSP setup. Please refer to following for an explanation of other BSP initialization options.

Configurations for setup script

MACHINE is the target of build. It usually corresponds to the name of SOM or SBC.
For more information, please check the file under “sources/meta-tn-imx-bsp/conf/machine”.

DISTRO identifies the Yocto distribution and is the new way to configure for any backends.

“-b” specify the build directory.

DISPLAY is the disply type. This option only works on i.MX6 (i.MX6 Solo/Dual Lite/Dual/Quad) SOMs. Does not work for products based on i.MX6UL/ULL, i.MX6SX, and i.MX7.

BASEBOARD is the baseboard type.

WIFI_MODULE is to choose what kind of WLAN is on board. (qca/brcm/ath-pci)

WIFI_FIRMWARE is to choose to add WLAN firmware files in target rootfs or not. (y/all)

Build configurations for supported hardware

The following is a list of valid options for MACHINE based on the hardware.

The following is a list of valid options for DISTRO.

The following is a list of valid options for BASEBOARD based on the hardware. The BASEBOARD parameter specifies the 'baseboard' variable in uEnv.txt.

WIFI_MODULE

The following is a list of valid options for WIFI_MODULE. This specifies the 'wifi_module' variable in uEnv.txt).

WIFI_FIRMWARE

The following is a list of valid options for WIFI_FIRMWARE.

Please refer to section "Prepare WIFI/BT firmware" to ensure you already put firmware files in the right place.

DISPLAY

The following is a list of valid options for DISPLAY. This parameter only works on i.MX6 and i.MX8M. This specifies the displayinfo variable in uEnv.txt.

-b : Specify the build directory name

Choosing Yocto target image

The following is a list of target image options:

Example BSP Setup and Build Commands for Supported Targets

Build Yocto for TechNexion target platform.

For EDM-G-IMX8MM

Xwayland image:

WIFI_FIRMWARE=y DISTRO=fsl-imx-xwayland MACHINE=edm-g-imx8mm source tn-setup-release.sh -b build-xwayland-edm-g-imx8mm

bitbake imx-image-full

For EDM-G-IMX8MN

Xwayland image:

WIFI_FIRMWARE=y DISTRO=fsl-imx-xwayland MACHINE=edm-g-imx8mn source tn-setup-release.sh -b build-xwayland-edm-g-imx8mn

bitbake fimx-image-full

For EDM-G-IMX8MP

Xwayland image:

WIFI_FIRMWARE=y DISTRO=fsl-imx-xwayland MACHINE=edm-g-imx8mp source tn-setup-release.sh -b build-xwayland-edm-g-imx8mp

bitbake imx-image-full

For EDM-IMX8MQ

Xwayland image:

WIFI_FIRMWARE=y DISTRO=fsl-imx-xwayland MACHINE=edm-imx8mq source tn-setup-release.sh -b build-xwayland-edm-imx8mq

bitbake imx-image-full

For PICO-IMX8MM

Xwayland image:

WIFI_FIRMWARE=y DISTRO=fsl-imx-xwayland MACHINE=pico-imx8mm source tn-setup-release.sh -b build-xwayland-pico-imx8mm

bitbake imx-image-full

For PICO-IMX8MQ

Xwayland image:

WIFI_FIRMWARE=y DISTRO=fsl-imx-xwayland MACHINE=pico-imx8mq source tn-setup-release.sh -b build-xwayland-pico-imx8mq

bitbake imx-image-full

For FLEX-IMX8MM

Xwayland image:

WIFI_FIRMWARE=y DISTRO=fsl-imx-xwayland MACHINE=flex-imx8mm source tn-setup-release.sh -b build-xwayland-flex-imx8mm

bitbake imx-image-full

For PICO-IMX7

PI baseboard, QT5 with X11 image for 7 inch/5 inch TTL-LCD panel:

For PICO-IMX7 with QCA WLAN:

WIFI_FIRMWARE=y WIFI_MODULE=qca DISTRO=fsl-imx-x11 MACHINE=pico-imx7 BASEBOARD=pi source tn-setup-release.sh -b build-x11-pico-imx7

bitbake imx-image-full

For TEP1-IMX7

PI baseboard, QT5 with X11 image for 7 inch/5 inch TTL-LCD panel:
For TEP1-IMX7 with QCA WLAN:

WIFI_FIRMWARE=y WIFI_MODULE=ath-pci DISTRO=fsl-imx-x11 MACHINE=tep1-imx7 source tn-setup-release.sh -b build-x11-pico-imx7

bitbake imx-image-full

For EDM-IMX6

FAIRY baseboard, QT5 with X11 image for 7 inch LVDS panel:
For EDM-IMX6 with QCA WLAN:

DISPLAY=lvds7 WIFI_FIRMWARE=y WIFI_MODULE=qca DISTRO=fsl-imx-x11 MACHINE=edm-imx6 BASEBOARD=fairy source tn-setup-release.sh -b build-x11-edm-imx6

bitbake imx-image-full

TC-0700/TC0710 baseboard, QT5 with X11 image for 7 inch LVDS panel:

DISPLAY=lvds7 WIFI_FIRMWARE=y WIFI_MODULE=qca DISTRO=fsl-imx-x11 MACHINE=edm-imx6 BASEBOARD=tc0700 source tn-setup-release.sh -b build-x11-edm-imx6

bitbake imx-image-full

For WANDBOARD-IMX6

QT5 with X11 image for HDMI:
For WANDBOARD-IMX6 with QCA WLAN:

DISPLAY=hdmi WIFI_FIRMWARE=y WIFI_MODULE=qca DISTRO=fsl-imx-x11 MACHINE=wandboard-imx6 source tn-setup-release.sh -b build-x11-wandboard-imx6

bitbake imx-image-full

For PICO-IMX6

PI baseboard, QT5 with X11 image for HDMI output:
For PICO-IMX6 with QCA WLAN:

WIFI_FIRMWARE=y WIFI_MODULE=qca DISTRO=fsl-imx-x11 MACHINE=pico-imx6 BASEBOARD=pi source tn-setup-release.sh -b build-x11-pico-imx6

bitbake imx-image-full

For PICO-IMX6UL/PICO-IMX6ULL

PI baseboard, QT5 with X11 image for 5" and 7" TFT-LCD output:
For PICO-IMX6UL/ULL with QCA WLAN:

WIFI_FIRMWARE=y WIFI_MODULE=qca DISTRO=fsl-imx-x11 MACHINE=pico-imx6ul BASEBOARD=pi source tn-setup-release.sh -b build-x11-pico-imx6ul

bitbake imx-image-full

Adding Support for the Chromium Browser

You may add support for Chromium in the file conf/local.conf. This file is generated during BSP setup and initialization, so it is only available to edit after running the steps above.

• For X11 on MX6 with GPU, add Chromium into your image

CORE_IMAGE_EXTRA_INSTALL += "chromium-x11 rng-tools"

• For XWayland or Wayland, add Chromium into your image

CORE_IMAGE_EXTRA_INSTALL += "chromium-ozone-wayland rng-tools"

QTWebkit

There are four Qt 5 browsers available. QtWebEngine browsers can be found in:

 /usr/share/qt5/examples/webenginewidgets/StyleSheetbrowser
 /usr/share/qt5/examples/webenginewidgets/Simplebrowser
 /usr/share/qt5/examples/webenginewidgets/Cookiebrowser
 /usr/share/qt5/examples/webengine/quicknanobrowser

All three browsers can be run by going to the directory above and running the executable found there. Touchscreen can be enabled by adding the parameters -plugin evdevtouch:/dev/input/event0 to the executable.

./quicknanobrowser -plugin evdevtouch:/dev/input/event0

QtWebengine will only work on SoC with GPU graphics hardware on i.MX 6, i.MX 7 and i.MX 8. To include Qtwebengine in the image put the following in local.conf or in the image recipe.

IMAGE_INSTALL_append = "packagegroup-qt5-webengine"

Qt 5

Note that Qt has both a commercial and open source license options. Make the decision about which license to use before starting work on custom Qt applications. Once custom Qt applications are started with an open source Qt license the work can not be used with a commercial Qt license. Work with a legal representative to understand the differences between each license.

NXP eIQ machine learning

The meta-ml layer is the integration of NXP eIQ machine learning, which was formerly released as a separate meta-imx-machinelearning layer and is now integrated into the standard BSP image (imx-image-full).

Note that many of the features require Qt 5. In case of using other configuration than imx-image-full, put the following in local.conf:

IMAGE_INSTALL_append = "packagegroup-imx-ml"

Systemd

Systemd support is enabled as default but it can be disabled by commenting out the systemd settings in imx/meta-sdk/conf/distro/include/fsl-imx-preferred-env.inc.

Image Deployment

When build completes, the generated release image is under “${BUILD-TYPE}/tmp/deploy/images/${MACHINE}”:

To decompress the .bz2:

bzip2 -fdk fsl-image-XXX.rootfs.wic.bz2 "fsl-image-XXX.rootfs.wic"

or use bmaptool to flash fsl-image-XXX.rootfs.wic.bz2 directly.

To deploy the image to your board, please follow the instructions for loading software into the flash or microSD card of your development kit.

Tutorial Video

We have put together a video showing this process, including download the image, into a PICO-IMX8M-MINI.