Yocto Build Release

DART-6UL - Yocto Morty 2.2.1 based on FSL Community BSP 2.2 with L4.1.15_2.0.0-ga Linux release

Installing required packages

Follow the link below and install all required packages on your machine.

www.yoctoproject.org/docs/latest/yocto-project-qs/yocto-project-qs.html

Please make sure your host PC is running Ubuntu 14.04/16.04 64-bit and install the following packages:

sudo apt-get install gawk wget git-core diffstat unzip texinfo gcc-multilib build-essential chrpath socat libsdl1.2-dev
sudo apt-get install autoconf libtool libglib2.0-dev libarchive-dev
sudo apt-get install python-git xterm sed cvs subversion coreutils texi2html
sudo apt-get install docbook-utils python-pysqlite2 help2man make gcc g++ desktop-file-utils libgl1-mesa-dev
sudo apt-get install libglu1-mesa-dev mercurial automake groff curl lzop asciidoc u-boot-tools dos2unix mtd-utils
sudo apt-get install pv

Documentation

• Yocto Project Core - Morty 2.2.1 (released on 02/24/2017)

Documentation is available from www.yoctoproject.org

• FSL Community BSP Release Notes 2.2 documentation

Documentation is available from http://freescale.github.io

• Kernel documentation from fsl-yocto-L4.1.15_2.0.0-ga release

Documentation is available for download from fsl-yocto-imx-4.1.15_2.0.0-docs

Download Yocto Morty based on Freescale Community BSP

$ git config --global user.name "Your Name"
$ git config --global user.email "Your Email"

$ mkdir ~/bin (this step may not be needed if the bin folder already exists)
$ curl http://commondatastorage.googleapis.com/git-repo-downloads/repo > ~/bin/repo
$ chmod a+x ~/bin/repo
$ export PATH=~/bin:$PATH

$ mkdir ~/var-fslc-yocto
$ cd ~/var-fslc-yocto
$ repo init -u https://github.com/varigit/variscite-bsp-platform.git -b morty
$ repo sync -j4

If you want to switch to one of the release tags follow Update Yocto Morty to Release Tag section

Setup and build Yocto

Supported images

The following images are provided by Variscite for evaluation purpose

• fsl-image-gui: Default Variscite demo image with a GUI without any QT content. This image recipe works on all backends for X11,DirectFB, Frame Buffer and Wayland and the content is optimized to fit 512MB NAND.
• fsl-image-qt5: Extends fsl-image-gui image with QT5.7.1 support and various QT samples for X11, Frame Buffer and Wayland backends.

Will result in image size greater than 512 MB, which will not fit into NAND-Flash. Use SD card or eMMC to test.

The following images are provided by FSL Community BSP:

• fsl-image-machine-test: A console-only image that includes gstreamer packages and test and benchmark applications.
• fsl-image-mfgtool-initramfs: Small image to be used with Manufacturing Tool (mfg-tool) in a production environment.

See the list of Yocto Project’s reference images in Yocto Project Reference Manual

Supported distros

The following distros can be used:

• fslc-x11: Distro for X11 without wayland. This distro include x11 feature and doesn’ has wayland support.
• fslc-framebuffer: Distro for Framebuffer graphical backend. This distro doesn’t include x11 and wayland features.
• fslc-wayland: Distro for Wayland without X11. This distro include wayland feature but doesn’t has x11 support.
• fslc-xwayland: Distro for Wayland with X11. This distro include both wayland and x11 features.

Note: Also standard Poky distros can be used

Build X11 GUI demo image

$ cd ~/var-fslc-yocto
$ MACHINE=imx6ul-var-dart DISTRO=fslc-x11 . setup-environment build_x11

Optional steps: local.conf customization

launch bitbake:

Without Qt content:
$ bitbake fsl-image-gui

Or with Qt content:
$ bitbake fsl-image-qt5

Build console-only demo image

$ cd ~/var-fslc-yocto
$ MACHINE=imx6ul-var-dart DISTRO=fslc-framebuffer . setup-environment build_fb

Optional steps: local.conf customization

Without Qt content:
$ bitbake fsl-image-gui

Or with Qt content:
$ bitbake fsl-image-qt5

local.conf customization

Change the downloads directory

Create a /opt/yocto_downloads directory and set its permissions:

$ sudo mkdir /opt/yocto_downloads
$ sudo chmod 777 /opt/yocto_downloads/

Direct downloads to it, by replacing 'DL_DIR ?= "${BSPDIR}/downloads/"' with 'DL_DIR = "/opt/yocto_downloads/"' in conf/local.conf:

$ sed -i 's/DL_DIR ?= "${BSPDIR}\/downloads/DL_DIR = "\/opt\/yocto_downloads/g' conf/local.conf

Add Eclipse debug and Qt creator support to your images

Append the following to the conf/local.conf file in your Yocto build directory, to add Eclipse debug and Qt creator support to your images:

EXTRA_IMAGE_FEATURES = " \
    debug-tweaks \
    tools-debug \
    eclipse-debug \
    "

IMAGE_INSTALL_append = " \
    tcf-agent \
    openssh-sftp-server \
    "

Use systemd instead of SysV init

Append the following to the conf/local.conf file in your Yocto build directory, to use systemd instead of SysV init in your images:

DISTRO_FEATURES_append = " systemd"
VIRTUAL-RUNTIME_init_manager = "systemd"
DISTRO_FEATURES_BACKFILL_CONSIDERED = "sysvinit"
VIRTUAL-RUNTIME_initscripts = ""
IMX_DEFAULT_DISTRO_FEATURES_append = " systemd"

Create a read-only root file system

Append the following to the conf/local.conf file in your Yocto build directory, to create a read-only rootfs:

EXTRA_IMAGE_FEATURES += "read-only-rootfs"

Build Results

The resulted images are located in tmp/deploy/images/imx6ul-var-dart.

Image Name	How to use
fsl-image-gui-imx6ul-var-dart.sdcard	This image is for SD card boot. It can be flashed as-is on an SD card that can then be used to boot your system, according to the relevant startup-guide of your product (usually requires to press the boot select button, or toggle a DIP switch). For detailed information refer to the Create a bootable SD card section below.
fsl-image-gui-imx6ul-var-dart.tar.bz2	Tarball with rootfs files. Can be used to create an NFS root file system on the host. See the Yocto Setup TFTP/NFS section for more info. Also used to create our extended SD card. See the Create a bootable SD card section below.
fsl-image-gui-imx6ul-var-dart.ubi	A complete UBI image containing a UBIFS volume, for writing to NAND Flash.
zImage	Linux kernel image, same binary for SD card or NAND Flash.
u-boot.img-nand	U-Boot built for NAND Flash.
u-boot.img-sd	U-Boot built for SD card boot or eMMC boot.
SPL-sd	SPL built for SD card boot or eMMC boot.
SPL-nand	SPL built for NAND Flash.

Image Name	How to use
fsl-image-gui-imx6ul-var-dart.sdcard	This image is for SD card boot. It can be flashed as-is on an SD card that can then be used to boot your system, according to the relevant startup-guide of your product (usually requires to press the boot select button, or toggle a DIP switch). For detailed information refer to the Create a bootable SD card section below.
fsl-image-gui-imx6ul-var-dart.tar.gz	Tarball with rootfs files. Can be used to create an NFS root file system on the host. See the Yocto Setup TFTP/NFS section for more info. Also used to create our extended SD card. See the Create a bootable SD card section below.
fsl-image-gui-imx6ul-var-dart.ubi	A complete UBI image containing a UBIFS volume, for writing to NAND flash.
zImage	Linux kernel image, same binary for SD card/eMMC or NAND flash.
SPL-sd	SPL built for SD card boot or eMMC boot.
SPL-nand	SPL built for NAND flash.
u-boot.img-sd	U-Boot built for SD card boot or eMMC boot.
u-boot.img-nand	U-Boot built for NAND flash.

File Name	Description
zImage-imx6ul-var-dart-emmc_wifi.dtb	Device tree blob for DART-6UL with eMMC & WI-FI enabled. (SD card & NAND disabled)
zImage-imx6ul-var-dart-nand_wifi.dtb	Device tree blob for DART-6UL with NAND flash & WI-FI enabled. (SD card & eMMC disabled)
zImage-imx6ul-var-dart-sd_emmc.dtb	Device tree blob for DART-6UL with SD card & eMMC enabled (WIFI & NAND disabled)
zImage-imx6ul-var-dart-sd_nand.dtb	Device tree blob for DART-6UL with SD card & NAND flash enabled (WIFI & eMMC disabled)
zImage-imx6ull-var-dart-emmc_wifi.dtb	Device tree blob for DART-6ULL with eMMC & WI-FI enabled. (SD card & NAND disabled)
zImage-imx6ull-var-dart-nand_wifi.dtb	Device tree blob for DART-6ULL with NAND flash & WI-FI enabled. (SD card & eMMC disabled)
zImage-imx6ull-var-dart-sd_emmc.dtb	Device tree blob for DART-6ULL with SD card & eMMC enabled (WIFI & NAND disabled)
zImage-imx6ull-var-dart-sd_nand.dtb	Device tree blob for DART-6ULL with SD card & NAND flash enabled (WIFI & eMMC disabled)

Create a bootable SD card

SD card structure

The SD card is divided into 3 sections as shown in the picture above:

• The first unallocated 4MiB are saved space for u-boot.img. They can be replaced with a dd command described in the Yocto Build U-Boot section.
  
• The first partition is a fat16 partition used for the device tree files and Linux uImage file. You can copy them as described in the Yocto Build Linux section.
  
• The second partition is an ext4 partition that contains the complete file system and modules.
  
  

Note:
The last unallocated area is not used. It is there so that the rootfs will fit on any 4GB SD card, as not all 4GB SD cards are really the same size. If you want, you can use a program such as GParted to resize the roofs partition and make it end at the end of your specific SD card (of course, you can also use SD cards with much bigger capacity than 4GB, and then it makes more sense to resize the partition).
Also, if you create the extended SD card yourself by following the Create an extended SD card section below, and you use the '-a' option, the rootfs partition will end at the end of your specific SD card automatically.

Yocto pre-built bootable SD card

The Yocto build products contains many files as explained in the Build Results section. For example, fsl-image-gui-imx6ul-var-dart.sdcard, depending on your build. This is a complete image to be flashed directly to an SD card.

Example usage:

$ sudo umount /dev/sdX*
# For GUI-X11 & QT5-X11
$ cd ~/var-fslc-yocto/build_x11
Or
# For QT5-FB
$ cd ~/var-fslc-yocto/build_fb 

# For fsl-image-gui image (GUI-X11)
$ sudo dd if=tmp/deploy/images/imx6ul-var-dart/fsl-image-gui-imx6ul-var-dart.sdcard of=/dev/sdX bs=1M && sync
Or
# For fsl-image-qt5 image (QT5-X11 & QT5-FB)
$ sudo dd if=tmp/deploy/images/imx6ul-var-dart/fsl-image-qt5-imx6ul-var-dart.sdcard of=/dev/sdX bs=1M && sync
Replace sdX with the right device name. This can be obtained by "dmesg" command on your host Linux PC, after the SD card reader is inserted.

• Note: Booting your system from an SD card requires pressing the boot-select button, or switching the relevant DIP switch to "Boot from SD card", according to the relevant start-up guide of your system"
  
  

Drawbacks of the native .sdcard yocto-built image:

• The second partition size doesn't use the entire SD card.
• The second partition is not labeled as rootfs.
• The NAND and eMMC flashing scripts are not included.

Create an extended SD card

Variscite provides the var-create-yocto-sdcard.sh script which creates our NAND/eMMC recovery SD card - an SD card based on the fsl-image-gui filesystem, which copies the NAND flash burning scripts and relevant binaries for your convenience.
Later, you will be able to follow either the more automatic Yocto Recovery SD card guide or the more manual VAR-SOM-MX6 NAND flash burning guide to burn your images to NAND flash or eMMC.

Note:
This is essentially the same as our pre-built Recovery SD image, with the following main differences:

• The Android recovery (Android-eMMC) is only present on the pre-built SD image, and not on the SD card built from the Yocto script.
  
• The pre-built image's rootfs partition size is 3700MiB, which is also the default size when using the script, but the script also has an option to set the rootfs partition size to fill the whole free space of the used SD card. Anyway, you can always resize the partition later with an external tool such as gparted.
  

Naturally, the pre-built image is more straight forward and easier to use, while the script method is easier to customize.

Usage:

• Follow the Setup and build Yocto guide, and bitbake fsl-image-gui.
• Plug-in the SD card to your Linux HOST PC, run dmesg and see which device is added (i.e. /dev/sdX or /dev/mmcblkX)

$ cd ~/var-fslc-yocto
$ sudo MACHINE=imx6ul-var-dart sources/meta-variscite-fslc/scripts/var_mk_yocto_sdcard/var-create-yocto-sdcard.sh <options> /dev/sdX
(Replace /dev/sdX with your actual device)

options:
 -h            Display help message
 -s            Only show partition sizes to be written, without actually write them
 -a            Automatically set the rootfs partition size to fill the SD card
 -r            Select alternative rootfs for recovery images (default: build_x11/tmp/deploy/images/imx6ul-var-dart/fsl-image-gui-imx6ul-var-dart.*)

If you don't use the '-a' option, a default rootfs size of 3700MiB will be used
The '-r' option allows you to create a bootable SD card with an alternative image for the installation to NAND flash or eMMC.
Example: "-r tmp/deploy/images/imx6ul-var-dart/fsl-image-qt5-imx6ul-var-dart" -- selected the "Qt5 image with X11" recovery image

Boot the board with a bootable SD card

Note: Booting from SD card eliminates WiFi as the WiFi and SD card are using the same SDIO interface.
A typical use-case, is to boot from an SD card, flash the eMMC/NAND flash, and re-boot from the eMMC/NAND flash to have WiFi operational.

Setting the Boot Mode

Booting your system from an SD card requires switching the Boot DIP switches. See picture below.

• "00" The current position in the picture will set the system to boot from SD card
• "01" Moving the right switch will set the system to boot from eMMC
• "10" Moving the left switch will set the system to boot from NAND flash
• "11" is illegal.

Be aware that your system has eMMC or NAND but never both.

Automatic device Tree selection in U-Boot

Enable/Disable Automatic Device Tree selection

To enable the automatic device tree selection in U-Boot (already enabled by default):

$ setenv fdt_file=undefined
$ saveenv

To disable the automatic device tree selection in U-Boot, set the device tree file manually:

$ setenv fdt_file=YOUR_DTB_FILE
$ saveenv

Comment:
Make sure you don't set am illegal value like "imx6ul-var-dart-sd_nand.dtb" in a SOM that has eMMC flash.

Flash images to NAND/eMMC

Please refer to Yocto NAND Flash Burning guide.

Yocto Image Customization

Update Yocto Morty to Latest HEAD

From time to time we will post updates to meta-variscite that will include new features and bug fixes.
Follow the instructions below to update your tree:

$ cd ~/var-fslc-yocto
$ repo init -b morty
$ repo sync

Update Yocto Morty to Release Tag

See the tag list at https://github.com/varigit

$ cd ~/var-fslc-yocto
$ repo init -b refs/tags/"tag name"
$ repo sync

Forcing Clean Build

In order to update the kernel, U-Boot and rootfs:
$ bitbake -c cleanall u-boot-variscite linux-variscite kernel-module-imx-gpu-viv ti-compat-wireless-wl18xx wl18xx-firmware cryptodev-module

for GUI image
$ bitbake -c clean fsl-image-gui
for Qt5 image
$ bitbake -c clean fsl-image-qt5

QT5 for Embedded Linux

To run QT5 applications without X11 backend the platform specific plugins (e.g. EGLFS or LinuxFB) should be configured with QT_QPA_PLATFORM environment variable or with -platform command-line.

See more information on QT5 customization for Embedded Linux here

Configure LinuxFB Plugin

DART-6UL supports only LinuxFB plugin

export QT_QPA_PLATFORM=linuxfb:fb=/dev/fb0:size=800x480:mmSize=160x95

Configure Touch Input

When no windowing system is present, the mouse, keyboard, and touch input are read directly via evdev or tslib.

Evdev

By default, the QT5 uses automatic device discovery based on libudev. In case you want to override the default touchscreen configuration the following parameters can be used:

• /dev/input/... - Specifies the name of the input device. When not given, Qt looks for a suitable device either via libudev or by walking through the available nodes.
• rotate - On some touch screens the coordinates must be rotated, which is done by setting rotate to 90, 180, or 270.
• invertx and inverty - To invert the X or Y coordinates in the input events, pass invertx or inverty.

export QT_QPA_EVDEV_TOUCHSCREEN_PARAMETERS='/dev/input/touchscreen0'

Tslib

Tslib is used for resistive single-touch touchscreens and should be pre-configured with:

export TSLIB_TSEVENTTYPE='INPUT'
export TSLIB_TSDEVICE='/dev/input/touchscreen0'
export TSLIB_CALIBFILE='/etc/pointercal'
export TSLIB_CONFFILE='/etc/ts.conf'
export TSLIB_CONSOLEDEVICE='none'
export TSLIB_FBDEVICE='/dev/fb0'
export TSLIB_PLUGINDIR='/usr/lib/ts'
export QT_QPA_EGLFS_TSLIB=1 
export QT_QPA_FB_TSLIB=1 

It is recommended to put the above setup inside /etc/profile.d/tslib.sh.

Running QT5 Application

$ cd /usr/share/qt5/examples/
$ touch/dials/dials --platform linuxfb
$ gui/rasterwindow/rasterwindow --platform linuxfb
$ touch/fingerpaint/fingerpaint  --platform linuxfb
$ widgets/mainwindows/mainwindow/mainwindow --platform linuxfb

UBIFS

By default we create ubifs image for 512MB NAND-flash size. You can change the size by editing ~/var-fslc-yocto/sources/meta-variscite-fslc/conf/machine/imx6ul-var-dart.conf
and comment / uncomment the relevant section based on size.

Make changes to the rootfs

The following is usually not the recommended way to work with Yocto.
You should usually create new specific recipes (.bb files) and/or append to specific present recipes by using .bbappend files.
However, if you are not yet experienced enough with Yocto, and you just want to quickly add your files to the resultant file system (or make any other change to it), you can do it in a general way, by using the following variable:

ROOTFS_POSTPROCESS_COMMAND

    Specifies a list of functions to call once the OpenEmbedded build system has created the root filesystem.
    You can specify functions separated by semicolons:

         ROOTFS_POSTPROCESS_COMMAND += "function; ... "                  

    If you need to pass the root filesystem path to a within a function, you can use ${IMAGE_ROOTFS},
    which points to the directory that becomes the root filesystem image. See the IMAGE_ROOTFS variable for more information. 

The functions will be called right after the root filesystem is created and right before it is packed to images (.sdcard, .ubi, .tar.bz2, etc.).

Example

Let's say you have your files that you want to put in the filesystem arranged on your host under a directory called /my_rootfs_additions, like the following:

my_rootfs_additions/
├── data
│   ├── example.m4v
│   └── example.bin
├── etc
│   └── example.conf
└── home
    └── root
        └── .example

And let's say you want to build the fsl-image-gui image.

Create a file called ~/var-fslc-yocto/sources/meta-variscite-fslc/recipes-images/images/fsl-image-gui.bbappend
with the following content:

add_my_files() {
    cp -r /my_rootfs_additions/*  ${IMAGE_ROOTFS}/
}

ROOTFS_POSTPROCESS_COMMAND += "add_my_files;"

Now, when you bitbake fsl-image-gui, the files in /my_rootfs_additions will be added to the rootfs (be careful when overwriting files).

Useful Bitbake commands

Bitbake Cheat Sheet

Useful bitbake commands

i.MX Yocto Project: ltib versus bitbake