conga-SMX8-Plus Yocto 4.0 (Kirkstone)

This section is a guideline how to build a Linux image for the i.MX 8M Plus based congatec modules, using the Yocto Project 4.0 (krikstone). The first section contains Linux Host Machine preparation, Yocto obtaining, and Linux image build. The second section describes how to include the software development tools in the target Linux image, and the third section describes how to build a cross-SDK for the Linux Host Machine.
For more information see the i.MX Yocto Project User's Guide

1. Linux image build

To get the Yocto Project expected behavior in a Linux Host Machine, the packages and utilities described below must be installed. An important consideration is the hard disk space required in the host machine. For example, when building on a machine running Ubuntu, the minimum hard disk space required is about 50 GB. It is recommended that at least 120 GB is provided, which is enough to compile all backends together. For building machine learning components, at least 250 GB is recommended.

The recommended minimum Ubuntu version is 20.04 or later. The latest release supports Chromium v91, which requires an increase to the ulimit (number of open files) to 4098.

1.1 Linux Host Machine preparation

Ubuntu 20.04 or newer is recommended but other environments are also possible.

1.1.1 Ubuntu 20.04

• The following tools have to be installed

Regarding the repo tool, it may be necessary to use newer version than the one provided via the operating system package above; the following steps are an example how to get access to such a version

1.1.2 Configure the local git

1.2 Obtaining Yocto

The Google's repo tool is used to obtain Yocto sources; the tool downloads all necessary files as defined in the provided manifest file. The manifest file therefore determines, among other things, specific version of boot loader and kernel that will be included in the target image.
The congatec Yocto sources and subsequently the manifest file are derived from a NXP GA release version; the mapping is in the table below, together with information about included boot loader and kernel version. In addition to the the base manifest file may be available manifest files adding specific functionality above the base NXP GA release. They would be also documented in the table.

The repo tool dowloads all files into the working directory, so it is a good idea to create a dedicated directory for the purpose, e.g.

All manifest files reside on the cgtimx8mp__imx-linux-kirkstone-5.15.32-2.0.0 branch of the manifest-imx8-family repository; the repo init command can be instructed to use either the latest version of the provided manifest file (subsection 1.2a) or a specific version (subsection 1.2b).

1.2a Using the latest available version

1.2b Using a specific version

The Git Commit SHA String is SHA of the commit that contains the desired version of Repo Manifest File

1.3 Configuration of the build directory and environment

The downloaded Yocto sources contain imx-setup-release.sh script that is used in this step to configure the build directory and build environment. The script takes three inputs in this example - machine the build is being made for (variable MACHINE), distribution to use (variable DISTRO) and name of the build directory (the -b parameter).
The Machine Identification is module dependent and is to be determined as per the table below; regarding distribution the options are fsl-imx-xwayland and fsl-imx-wayland

Note: The configured environment is not persistent; it can be re-configured using command source setup-environment build-dir

1.4. The fsl-image-validation-imx image building

The last step is the image build itself; the bitbake tool does that, taking at least one parameter - the name of the image to build (i.e. the bitbake image name).

The available i.MX images are: core-image-minimal, core-image-base, fsl-image-machine-test, imx-image-core, imx-image-multimedia, and imx-image-full.

After the bitbake finishes, the following files can be found in the tmp/deploy/images/\<Machine Identification\> subdirectory of the build folder.

Note that this table does not contain all files in the subdirectory

2. Include SDK in the target image (optional)

Development tools and libraries can be included in the target Linux image, which makes software development on the module itself possible. Yocto's features tools-sdk and dev-pkgs are available for the purpose - after the build directory and environment are configured (i.e. after the step 1.3), the features need to be added to the EXTRA_IMAGE_FEATURES variable in theconf/local.conf file. An example that shows the default variable after the update follows

The development tools and libraries will be included during the subsequent bitbake run.

3. Build, install, and use the cross-SDK on the Linux Host Machine

The Yocto system is able to build a cross-SDK that can be used for software development on the Linux Host Machine. The command that builds an installation package for the SDK can be invoked after the 1.3 or 1.4 steps.

3.1 Build the cross-SDK installation package

Note: The installation package is located in the tmp/deploy/sdk subdirectory after the build

3.2 Install the SDK

3.3 Source the SDK toolchain

To use the cross-SDK on the Linux Host Machine, the SDK setup file needs to be sourced as follows

Note: The /opt/fsl-imx-xwayland is the default destination directory as proposed by the SDK installer

4. Boot from QSPI

With the above created system image the system boots from SD-Card. It is possible to boot from QSPI if the bootcontainer is flashed inside first SPI partition.
A valid bootcontainer with the current bootloader is built during the image build process with yocto. It is also inside the yocto deploy folder.
For QSPI we have to use the following bootcontainer file, depending on module:

• bootcontainer__imx8mp-cgtqx8p__fspi.bin for conga-QMX8-Plus

• bootcontainer__imx8mp-cgtsx8p__fspi.bin for conga-SMX8-Plus

Then flashing to QSPI could be done in different ways:

4.1 Update bootcontainer from running Linux on module

1. Copy the bootcontainer to the SD-card to boot from

2. Boot the system

3. Erase bootloader partition of SPI-Flash:

4. Copy bootcontainer to flash

4.2 Update bootcontainer with UUU tool

4.2.1 Module setup

Use the USB-OTG port of conga-QMX8-Plus/conga-SMX8-Plus to update the bootcontainer. The procedure is the same, but the bootmode switches differ on the different platforms:

4.2.1.1 Bootmode switches conga-QMX8-Plus

The Q7 module itself does not have any boot switches. Check the backplane manual for details.

4.2.1.2 Bootmode switches conga-SMX8-Plus

FORCE_RECOV# (S155) pin on the SMARC connector has to be pulled low. Check the backplane manual for details.

4.2.2 Flash

1. Connect the host system with an USB OTG cable to module

2. Start uuu tool (version 1.4.243)

3. Power up module and wait until flash has finished

4. Power off module

5. Set boot mode switches to standard boot

6. Power up and check uboot version

5. Transfering the BSP image to uSD card

In order to transfer the image to a uSD card, follow the next steps changing sdX for your detected device.

5.1 conga-QMX8-Plus

5.2 conga-SMX8-Plus

The root partition on u-SD card does exactly fit to the data used and does not have many extra space. It could be expanded up to the end of the available sdcard space with a graphical tool like gparted or on command line with parted (install it if needed).