VAR-SOM-MX6 Yocto Fido R4 Build Yocto release

From Variscite Wiki
VAR-SOM-MX6 - Yocto fsl-4.1.15_1.1.0_ga Jethro R4 Build Yocto release

1 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

For example, if your building machine is an Ubuntu machine:

sudo apt-get install gawk wget git-core diffstat unzip texinfo gcc-multilib build-essential chrpath socat libsdl1.2-dev xterm lib32ncurses5-dev

Variscite Yocto build was tested with Ubuntu 12.04 LTS and Ubuntu 14.04 LTS only!

2 Documentation

Documentation are available for Download from FreescaleJethroDocuments

3 Download Yocto Jethro for i.MX6 Freescale source

$ 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-som-mx6-yocto-jethro
$ cd ~/var-som-mx6-yocto-jethro
$ repo init -u git://git.freescale.com/imx/fsl-arm-yocto-bsp.git -b imx-4.1.15-1.0.0_ga
$ repo sync

4 Download Yocto Jethro i.MX6 with Meta Variscite VAR-SOM-MX6 support

$ cd ~/var-som-mx6-yocto-jethro/sources
$ git clone https://github.com/varigit/meta-variscite-mx6/
$ git chekcout -b imx-4.1.15-1.0.0_ga-VAR01-beta remote/origin/imx-4.1.15-1.0.0_ga-VAR01-beta
$ cd meta-variscite-mx6/
$ cp scripts/var-setup-release.sh ../../
$ cd ../meta-fsl-bsp-release
$ patch -p1 < ../meta-variscite-mx6/patch/0001-Fix-FSL-multi-patch-append-bug.patch

5 Setup and build Yocto

You can create an image for QT5/X11 or create an image for QT5/Embedded. Please select one of the following option:

5.1 Build a Freescale image with a GUI without any Qt content

$ cd cd ~/var-som-mx6-yocto-jethro
$ DISTRO=fsl-imx-x11 MACHINE=var-som-mx6 source var-setup-release.sh -b build_x11
$ bitbake fsl-image-gui

5.2 Build an opensource Qt 5 image

$ cd cd ~/var-som-mx6-yocto-jethro
$ DISTRO=fsl-imx-fb MACHINE=imx6qpsabreauto source fsl-setup-release.sh –b build-fb
$ bitbake fsl-image-qt5

5.3 local.conf customizations

Edit you local.conf file:

$ gedit conf/local.conf 

Change parallel build and download directory: Set the build parameters to fully utilize your host machine's resources
BB_NUMBER_THREADS = '4'
PARALLEL_MAKE = '-j 6'
BB_NUMBER_THREADS should be your host machine's number of threads minus 2 or same. PARALLEL_MAKE should be the number of threads your host machine has plus two.

Change packages download directory. By default it is set to: DL_DIR ?= "${BSPDIR}/downloads/" change it to a global folder like DL_DIR ?= "/opt/yocto_dl/". Don't forget to create the folder and make it available without a sudo permissions.

NOTE:
If you don't need Chromium browser edit conf/local.conf and comment out the chromium line.

5.4 Build Results

The resulted images are locaated in tmp/deploy/images/var-som-mx6.

Image Name
How to use
fsl-image-qt5-minimal-var-som-mx6.sdcard

fsl-image-qt5-var-som-mx6.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-qt5-minimal-var-som-mx6.tar.bz2

fsl-image-qt5-var-som-mx6.tar.bz2
Used to create an NFS root file system on the host. See the Setup TFTP/NFS Yocto system section for more info.
Also used to create our extended SD card. See the Create a bootable SD card section below.
fsl-image-qt5-minimal-var-som-mx6.ubi A complete UBI image containing a UBIFS volume, for writing to NAND Flash.
uImage Linux kernel image, same binary for SD card or NAND Flash.
SPL-nand SPL built for NAND-Flash. The SPL is a pre-U-Boot SW component, required for DDR initialization.
u-boot-nand-2015.04-r0.img U-Boot built for NAND Flash.
SPL-sd SPL built for SD card boot, or eMMC boot in case of DART-MX6.
u-boot-sd-2015.04-r0.img U-Boot built for SD card boot, or eMMC boot in case of DART-MX6.
Device Tree Name
SOM type
Carrier Board type
LCD Type
Evaluation Kit name
uImage-imx6q-var-som.dtb VAR-SOM-MX6_V2 (Quad / Dual) VAR-MX6CustomBoard Capacitive/Resistive touch VAR-DVK-MX6_V2-PRO
VAR-STK-MX6_V2
uImage-imx6q-var-som-vsc.dtb VAR-SOM-MX6_V2 (Quad / Dual) VAR-SOLOCustomBoard Capacitive LVDS touch N/A
uImage-imx6dl-var-som.dtb VAR-SOM-MX6_V2 (DualLite/ Solo) VAR-MX6CustomBoard Capacitive/Resistive touch N/A
uImage-imx6dl-var-som-solo-vsc.dtb VAR-SOM-SOLO / VAR-SOM-DUAL VAR-SOLOCustomBoard Capacitive LVDS touch VAR-DVK-SOLO/DUAL VAR-STK-SOLO/DUAL
uImage-imx6dl-var-som-solo.dtb VAR-SOM-SOLO / VAR-SOM-DUAL VAR-MX6CustomBoard Capacitive/Resistive touch N/A
uImage-imx6q-var-dart.dtb VAR-SOM-SOLO / VAR-SOM-DUAL VAR-DT6CustomBoard Capacitive LVDS touch VAR-STK-DT6.VAR-DVK-DT6

6 Create a bootable SD card

6.1 SD card structure

This is the structure of our Recovery/Extended SD card:
SD card part v50.png

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

  • The first unallocated 4MiB are saved space for SPL and u-boot.img. They can be replaced with a dd command described in the Build U-Boot out of Yocto tree 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 Linux out of tree 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.

6.2 Yocto pre-built bootable SD card

The Yocto build products contains many files as explained in the Build Results section. For example, fsl-image-qt5-minimal-var-som-mx6.sdcard or fsl-image-qt5-var-som-mx6.sdcard, depending on your build. This is a complete image to be flashed directly to an SD card.

Example usage:

$ cd ~/var-som-mx6-yocto-Jethro/build_x11
$ sudo dd if=tmp/deploy/images/var-som-mx6/fsl-image-qt5-var-som-mx6.sdcard of=/dev/sdX bs=1M
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 is ext3 (not ext4)
  • 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.

6.3 Create an extended SD card

Variscite provides the var-create-yocto-sdcard.sh script which creates our NAND/eMMC recovery rescue SD card - an SD card based on the fsl-image-qt5-var-som-mx6 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 VAR-SOM-MX6 Yocto NAND Recovery 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 NAND 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 both fsl-image-qt5-minimal (used for the Yocto-NAND installation) and fsl-image-qt5 (used for the Yocto-eMMC installation and for the rootfs of the SD card itself).
  • 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)
sudo ~/var-som-mx6-yocto-Jethro/sources/meta-variscite-mx6/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

If you don't use the '-a' option, a default rootfs size of 3700MiB will be used

7 Flash images to NAND

Please refer to VAR-SOM-MX6 NAND Flash burning

8 Boot the board with a bootable SD card

8.1 Booting your specific Developer Kit

Select the one you are using.

8.1.1 MX6CustomBoard

Booting your MX6CustomBoard system from SD card requires while powering up the system. See picture below.

Mx6 boot.jpg

To boot a board using an SD card, follow the steps below:

  • Power-off the board.
  • Insert the SD card into the SD/MMC slot of the carrier board (DVK)
  • Push the middle button (Boot Select) and hold
  • Power-up the board
  • Release the middle button (Boot Select) after system starts to boot.
  • The board will automatically boot into Linux from the SD card

8.1.2 SoloCustomBoard

Booting your system requires switching the relevant DIP switch to "Boot from MMC". See picture below.

Solo boot.jpg

To boot board with SD card, Follow the steps below:

  • Power-off the board.
  • Insert the SD card into the SD/MMC slot of the carrier board (DVK)
  • Switch the relevant DIP switch to "Boot from MMC"
  • Power-up board
  • The board will automatically boot into Linux from SD card

8.1.3 DT6CustomBoard

Booting your system requires switching the relevant DIP switch to "Boot from SD card". See picture below.

Dart boot.jpg

To boot board with SD card, Follow the steps below:

  • Power-off the board.
  • Insert the SD card into the SD/MMC slot of the carrier board (DVK)
  • Switch the relevant DIP switch to "Boot from SD card"
  • Power-up board
  • The board will automatically boot into Linux from SD card

8.2 Automatic Device Tree selection in U-Boot

Upon reset you will see the U-Boot SPL printouts. It will print the SOM configuration:

  • CPU type and frequency
  • Production information
  • RAM size
  • Boot Device: eMMC, SD or NAND
  • NAND size (if boot device is NAND)

For example:

U-Boot SPL 2015.04 (Mar 20 2016 - 11:29:03)

i.MX6Q SOC P-STD
996 MHz CPU (running at 792 MHz)
Part number: VSM-MX6-C01
Assembly: AS16
Date of production: 2016 Mar 21
RAM: 1 GiB
Boot Device: NAND
NAND : 512 MiB

As explained in the above Build Results table, we have 6 optional configurations.
We implemented an automatic device tree selection in U-Boot, when booting from SD card, so when the kernel boots, the U-Boot will load the corresponding device tree according to On-SOM configuration.
Based on the hardware we will set 2 environment variables in U-Boot.

  • fdt_file - Will be set to reflect the SOM/CustomBoard pair.
  • screen_alternate=yes - Will be appended to bootargs in case you are using the capacitive display.

The table below list the possible options:

SOM type
Carrier Board type
LCD Type
Evaluation Kit name
Device Tree Name
Screen Alternate
VAR-SOM-MX6_V2 (Quad / Dual) VAR-MX6CustomBoard Capacitive touch VAR-DVK-MX6_V2-PRO
VAR-STK-MX6_V2
imx6q-var-som.dtb Yes
VAR-SOM-MX6_V2 (Quad / Dual) VAR-MX6CustomBoard Resistive touch VAR-DVK-MX6_V2-PRO
VAR-STK-MX6_V2
imx6q-var-som.dtb No
VAR-SOM-MX6_V2 (Quad / Dual) VAR-SOLOCustomBoard Capacitive LVDS touch N/A imx6q-var-som-vsc.dtb N/A
VAR-SOM-MX6_V2 (DualLite/ Solo) VAR-MX6CustomBoard Capacitive touch N/A imx6dl-var-som.dtb Yes
VAR-SOM-MX6_V2 (DualLite/ Solo) VAR-MX6CustomBoard Resistive touch N/A imx6dl-var-som.dtb No
VAR-SOM-SOLO / VAR-SOM-DUAL VAR-SOLOCustomBoard Capacitive LVDS touch VAR-DVK-SOLO/DUAL VAR-STK-SOLO/DUAL imx6dl-var-som-solo-vsc.dtb N/A
VAR-SOM-SOLO / VAR-SOM-DUAL VAR-MX6CustomBoard Capacitive/Resistive touch N/A imx6dl-var-som-solo.dtb N/A
VAR-SOM-SOLO / VAR-SOM-DUAL VAR-DT6CustomBoard Capacitive LVDS touch VAR-STK-DT6.VAR-DVK-DT6 imx6q-var-dart.dtb N/A

8.3 Disable Automatic Device Tree selection

To disable the automatic device tree selection in U-Boot:

$ setenv var_auto_fdt_file=N
$ saveenv

Now you can set the device tree to meet your requirements. For example:

$ setenv fdt_file=imx6q-var-som.dtb
$ screen_alternate=yes
$ saveenv

Will select device tree that has i.MX6 Quad/Dual running on MX6CustomBoard.

Comment:
Make sure you don't set an illegal value like "imx6q-var-som.dtb" in a QUAD that is running on SoloCustomBoard.

8.4 What happen when you flash to eMMC/NAND

When you flash to NAND we use the same algorithm as the table above but we pick and choose specific device tree and flash it.

9 QT5/Embedded environment variables

The QT5/Embedded require environment variables to run correctly. You need to have them avilable on the target. For example /etc/profile.d/tslib.sh can be edited.

export TSLIB_TSDEVICE=/dev/input/touchscreen0
export TSLIB_CALIBFILE=/etc/pointercal
export TSLIB_CONFFILE=/etc/ts.conf
export QT_QPA_GENERIC_PLUGINS=tslib:/dev/input/event0
export QT_QPA_EGLFS_PHYSICAL_HEIGHT=480
export QT_QPA_EGLFS_PHYSICAL_WIDTH=800
export QT_QPA_EGLFS_HEIGHT=480
export QT_QPA_EGLFS_WIDTH=800
export QT_EGLFS_IMX6_NO_FB_MULTI_BUFFER=1
export QT_QPA_EGLFS_DEPTH=24
export QT_QPA_PLATFORM=linuxfb:fb=/dev/fb0:size=800x480:mmSize=800x480

10 UBIFS

By default we create ubifs image for 0.5GB NAND size. You can change the size by editing ~/var-som-mx6-yocto-Jethro/sources/meta-variscite-mx6/conf/machine/var-som-mx6.conf
and comment / uncomment the relevant section based on size.


Another option is to create the ubifs image manualy. 4GB NAND example:

$ cd ~/var-som-mx6-yocto-Jethro
$ sudo mkdir rootfs
$ sudo tar xvf build_x11/tmp/deploy/images/var-som-mx6/fsl-image-qt5-var-som-mx6.tar.bz2 -C rootfs/
$ sudo mkfs.ubifs -r rootfs/ -o fsl-image-qt5-var-som-mx6q4.ubifs -m 4096 -e 504KiB -c 7835
$ ubinize -o fsl-image-qt5-var-som-mx6q4.ubi -m 4096 -p 512KiB -s 4096 -O 4096 ubinize.cfg
$ cat ubinize.cfg 
[ubifs]
mode=ubi
image=fsl-image-qt5-var-som-mx6.ubifs
vol_id=0
vol_type=dynamic
vol_name=rootfs
vol_flags=autoresize

11 DDR size and Contiguous Memory Allocator

By default Freescale allocates 256MB of RAM to the Contiguous Memory allocator. This is for proper operation of the IPU VPU, X11 etc. On VAR-SOM-SOLO with 256MB DDR RAM size, it will cause a kernel freeze during boot. Adding cma=32MB to the bootargs parameters is required to fix.

12 Next steps

In sections 1-6 we explained how to build Yocto for VAR-SOM-MX6. We explained the results for NAND (UBI) and for SD card. At this point you should have a bootable SD card with UBI images on it. You should be able to boot from the SD card using the boot select button and flash the NAND. Next steps:

  • Build and deploy the compiler and tools.
  • Fetch U-Boot and compile it out of Yocto tools.
  • Fetch Linux kernel and compile it out of Yocto tools.

13 Update Yocto Jethro i.MX6 Meta Variscite VAR-SOM-MX6 support

From time to time we will post updates to meta-variscite. This will include improve features and bug fix. You can track the history log in the previous page to see if such an update was posted. In such a case follow the instructions below to update your tree.

$ cd ~/var-som-mx6-yocto-Jethro/sources/meta-variscite-mx6/
$ git fetch origin
$ git pull
Set your enviroment
$ cd ~/var-som-mx6-yocto-Jethro
$ . ./setup-environment build_x11
In order to update the kernel
$ bitbake -c cleanall linux-variscite
$ bitbake -c cleanall ti-compat-wireless-wl18xx
and build your image
$ bitbake fsl-image-qt5


14 Useful Bitbake commands

Bitbake Cheat Sheet

Useful bitbake commands

i.MX Yocto Project: ltib versus bitbake