DESK-MX6UL-L/pdf

History

DESK-MX6UL-L History
Version	Issue Date	Notes	Refers to
1.0.1	Jun 2021	First DESK release	AXEL ULite SOM
			SDV04
			SBC Lynx SBC
3.0.0	Mar 2022	Update to NXP 5.10.35	AXEL ULite SOM
			SDV04
			SBC Lynx SBC
4.0.0	Mar 2023	Update to NXP 5.15.71	AXEL ULite SOM
			SDV04
			SBC Lynx SBC
4.0.1	Jun 2023	Minor update	AXEL ULite SOM
			SDV04
			SBC Lynx SBC
4.1.0	Jul 2024	LTS Kernel update	AXEL ULite SOM
			SDV04
4.2.1	Oct 2024	RIALTO support and CVE fixes	AXEL ULite SOM
			SDV04
			RIALTO SBC
6.0.0	Dec 2025	Update to NXP 6.6.52	AXEL ULite SOM
			SDV04
			RIALTO SBC

General Information

Release Notes

DAVE Embedded Systems adds to the Linux BSP from NXP the customization required to support the SOC platform. For this reason most of the documentation provided by NXP remains valid for the DESK development kit.

However, some customization is required, in particular at bootloader and linux kernel levels.

The following table reports the DESK releases information.

	DESK version
Release number	6.0.0
Release type	Major
Status	Released
Release date	Dec 2025
Release notes	Ver 6.0.0
Product support	AXEL ULite, RIALTO SBC
MVM (distro version)	Ubuntu 20.04
U-Boot version	2024.04-desk-mx6ul-l-6.0.0
Linux version	6.6.52-desk-mx6ul-l-6.0.0
Drivers	SPI NOR Flash (boot) NAND UART debug (2-wire) USB Host SD/MMC1 RTC RS232 RS485 I2C SPI ConfigID
Manufacturer BSP version	lf-6.6.52-2.2.1
Graphic libraries	N.A.
Build System	Yocto Scarthgap (5.0)

DESK-MX6UL-L 6.0.0

Release notes:

• update u-boot and linux to desk-mx6ul-l-6.0.0
• update the meta-layer to Scarthgap

Known Issues

The following table reports the known limitations of this DESK release:

Issue	Description
NOR Boot	NOR boot performances very slow
NAND Boot	SBC-Rialto doesn't support boot from NAND
Linux kernel	LCD panel not supported yet

Downloadable binary images

All binary images for DESK-MX6UL-L are hosted on DAVE Embedded System mirror server. There is a sub-directory for each version of this development kit.

U-Boot performs a 2-stage bootloader providing two files: SPL and u-boot.img. Both files must be stored on an SD card using the dd command.

A summary of images with a brief description can be found in the table below:

Image	DESK-MX6UL-L 6.0.0
Platform	SDV04 - SDV0400011C2R	RIALTO SBC - DVRTA00330D2R
Carrier Board ConfigID	003a	0090
LCD panel	Ampire 800 x 480 7" LVDS 262K colors
SPL	SPL	SPL
u-boot.img	u-boot.img	u-boot.img
Linux kernel	uImage	uImage
Device tree	imx6ul-axelulite-cb003a.dtb	imx6ul-lynx-som0022-cb0090.dtb
root file system	dave-image-minimal-desk-mx6ul-axelulite	dave-image-minimal-desk-mx6ul-rialto

DESK-MX6UL-L 4.2.1

Release notes:

• add support to RIALTO SBC
• update u-boot and linux to desk-mx6ul-l-4.2.0
• add public repo to bluez
• disable splash variable
• update the following meta-layer to the latest version of Kirkstone. With this update, we include CVE fixes
  • Poky to the version 4.0.20
  • meta-openembedded
  • meta-browser
  • meta-java
  • meta-timesys
  • meta-clang
  • meta-virtualization

Known Issues

The limitations are the same of DESK-MX6UL-L-4.0.0

Downloadable binary images

All binary images for DESK-MX6UL-L are hosted on DAVE Embedded System mirror server. There is a sub-directory for each version of this development kit.

U-Boot performs a 2-stage bootloader providing two files: SPL and u-boot.img. Both files must be stored on an SD card using the dd command.

A summary of images with a brief description can be found in the table below:

Image	DESK-MX6UL-L 4.2.1
Platform	SDV04 - SDV0400011C2R	RIALTO SBC - DVRTA00330D2R
Carrier Board ConfigID	003a	0090
LCD panel	Ampire 800 x 480 7" LVDS 262K colors
SPL	SPL	SPL
u-boot.img	u-boot.img	u-boot.img
Linux kernel	uImage	uImage
Device tree	imx6ul-axelulite-cb003a.dtb	imx6ul-lynx-som0022-cb0090.dtb
root file system	dave-image-devel-desk-mx6ul-axelulite	dave-image-devel-desk-mx6ul-rialto

Yocto images and built-in packages

Yocto target images for DESK-MX6UL-L are hosted on DAVE Embedded System mirror server. More build targets include a list of built and installed packages in the root file system image.

A summary of built images and their included packages can be found in the table below:

Image	DESK-MX6UL-L version 4.2.1
	SD card image	rootfs packages list
devel AxelULite	desk-image-devel.bz2	image-devel_installed-packages.txt
qt6 FB AxelULite	desk-image-qt6-fb.bz2	image-qt6-fb_installed-packages.txt
devel RIALTO SBC	desk-image-devel.bz2	image-devel_installed-packages.txt

DESK-MX6UL-L 4.1.0

Release notes:

• drop support for Lynx platform
• introduced KAS support for building system
• update to NXP lf-5.15.71-2.2.2
• remove some kernel runtime warnings/error

Known Issues

The limitations are the same of DESK-MX6UL-L-4.0.0

Downloadable binary images

All binary images for DESK-MX6UL-L are hosted on DAVE Embedded System mirror server. There you can find a sub directory for each version of this development kit.

U-Boot performs 2-stage bootloader providing two files: SPL and u-boot.img. Both two files must be stored into SD card using dd command.

A summary of images with a brief description can be found into the table below:

Image	DESK-MX6UL-L 4.1.0
Platform	SDV04 - SDV0400011C2R
Carrier Board ConfigID	003a
LCD panel	Ampire 800 x 480 7" LVDS 262K colors
SPL	SPL
u-boot.img	u-boot.img
Linux kernel	uImage
Device tree	imx6ul-axelulite-cb003a.dtb
root file system	dave-image-devel-desk-mx6ul-axelulite

Yocto images and built-in packages

Yocto target images for DESK-MX6UL-L are hosted on DAVE Embedded System mirror server. There are more build targets which include a list of built and installed packages in the root file system image.

A summary of built images and their included packages can be found in the table below:

Image	DESK-MX6UL-L version 4.1.0
	root file system	packages list
devel	desk-image-devel.bz2	image-devel_installed-packages.txt
qt6 fb	desk-image-qt6-fb.bz2	image-qt6-fb_installed-packages.txt

DESK-MX6UL-L 4.0.1

Release notes:

• Minor change to DESK-MX6UL-L-4.0.0
• add missing linuxfb platform for iMX6UL
• add missing fonts and Qt6 examples

Known Issues

The limitations are the same of DESK-MX6UL-L-4.0.0

Downloadable binary images

All binary images for DESK-MX6UL-L are hosted on DAVE Embedded System mirror server. There you can find a sub directory for each version of this development kit.

U-Boot performs 2-stage bootloader providing two files: SPL and u-boot.img. Both two files must be stored into SD card using dd command.

A summary of images with a brief description can be found into the table below:

Image	DESK-MX6UL-L 4.0.1
Platform	SDV04 - SDV0400011C2R	SBC Lynx - SXUB4000I3R
Carrier Board ConfigID	003a	002f
LCD panel	Ampire 800 x 480 7" LVDS 262K colors	N.A.
SPL	SPL	SPL
u-boot.img	u-boot.img	u-boot.img
Linux kernel	uImage
Device tree	imx6ul-axelulite-cb003a.dtb	imx6ul-lynx-som0013-cb002f.dtb
root file system	dave-image-devel-desk-mx6ul-axelulite	dave-image-devel-desk-mx6ul-lynx

DESK-MX6UL-L 4.0.0

New MVM must be installed for using DESK-MX6UL-L-4.0.0. The VM is available for download on DAVE's XELK Reserved Area for registered users.

Release notes:

• Major change to NXP BSP 5.15.71
• Updated U-Boot and kernel versions
• Updated Yocto version
• Updated Qt version

Known Issues

The following table reports the known limitations of this DESK release:

Issue	Description
Linux kernel xconfig	make xconfig does not work

Downloadable binary images

All binary images for DESK-MX6UL-L are hosted on DAVE Embedded System mirror server. There you can find a sub directory for each version of this development kit.

U-Boot performs 2-stage bootloader providing two files: SPL and u-boot.img. Both two files must be stored into SD card using dd command.

A summary of images with a brief description can be found into the table below:

Image	DESK-MX6UL-L 4.0.0
Platform	SDV04 - SDV0400011C2R	SBC Lynx - SXUB4000I3R
Carrier Board ConfigID	003a	002f
LCD panel	Ampire 800 x 480 7" LVDS 262K colors	N.A.
SPL	SPL	SPL
u-boot.img	u-boot.img	u-boot.img
Linux kernel	uImage
Device tree	imx6ul-axelulite-cb003a.dtb	imx6ul-lynx-som0013-cb002f.dtb
root file system	dave-image-devel

DESK-MX6UL-L 3.0.0

New MVM must be installed for using DESK-MX6UL-L-3.0.0. The VM is available for download on DAVE's XELK Reserved Area for registered users.

Release notes:

• Major change to NXP BSP 5.10.35
• Updated U-Boot and kernel versions
• Updated Yocto version
• Updated Qt version

Known Issues

The following table reports the known limitations of this DESK release:

Issue	Description
Qt5 linuxfb not working	platform linuxfb is not present on desk-image-qt5 image target
Linux kernel xconfig	make xconfig does not work

Downloadable binary images

All binary images for DESK-MX6UL-L are hosted on DAVE Embedded System mirror server. There you can find a sub directory for each version of this development kit.

U-Boot performs 2-stage bootloader providing two files: SPL and u-boot.img. Both two files must be stored into SD card using dd command.

A summary of images with a brief description can be found into the table below:

Image	DESK-MX6UL-L 3.0.0
Platform	SDV04 - SDV0400011C2R	SBC Lynx - SXUB4000I3R
Carrier Board ConfigID	003a	002f
LCD panel	Ampire 800 x 480 7" LVDS 262K colors	N.A.
SPL	SPL	SPL
u-boot.img	u-boot.img	u-boot.img
Linux kernel	uImage
Device tree	imx6ul-axelulite-cb003a.dtb	imx6ul-lynx-som0013-cb002f.dtb
root file system	dave-image-devel

DESK-MX6UL-L 1.0.1

New MVM must be installed for using DESK-MX6UL-L-1.0.1. The VM is available for download on DAVE's XELK Reserved Area for registered users.

Release notes:

• Major change to NXP BSP 4.14.98
• Updated U-Boot and kernel versions
• Updated Yocto version
• Updated Qt version

Known Issues

The following table reports the known limitations of this DESK release:

Issue	Description
Qt5 linuxfb not working	platform linuxfb is not present on desk-image-qt5 image target
Linux kernel xconfig	make xconfig does not work

Downloadable binary images

All binary images for DESK-MX6UL-L are hosted on DAVE Embedded System mirror server. There you can find a sub directory for each version of this development kit.

U-Boot performs 2-stage bootloader providing two files: SPL and u-boot.img. Both two files must be stored into SD card using dd command.

A summary of images with a brief description can be found into the table below:

Image	DESK-MX6UL-L 1.0.1
Platform	SDV04 - SDV0400011C2R	SBC Lynx - SXUB4000I3R
Carrier Board ConfigID	003a	002f
LCD panel	Ampire 800 x 480 7" LVDS 262K colors	N.A.
bootscript	boot.scr
SPL	SPL	SPL
u-boot.img	u-boot.img	u-boot.img
Linux kernel	uImage
Device tree	imx6ul-axelulite-cb003a.dtb	imx6ul-lynx-som0013-cb002f.dtb
root file system	dave-image-devel

Release types

DESK release type can be:

• Major, when substantial changes are applied to the BSP (eg: major kernel version upgrades) or to the development kit (eg: new features, build system updates, ..). This usually means that a new DVDK is created for the DESK release
• Maintenance, when minor updates and bug fixes are introduced. This usually means that the DVDK remains the same provided with the previous major version, and only an update of the source tree repositories (and the tftp binaries) is required

As an example, DESK 1.1.0 is a maintenance release, so it provides the DVDK released with the 1.0.0 major release; customers can easily upgrade to the 1.1.0 release by updating the software components as described in Synchronizing git repositories.

Supported platforms

The following table reports the supported platforms in this DESK release:

Platform	Description
SBC Lynx	Single Board Computer using the i.MX6UL SOC
SDV04	Single Board Computer using AXEL_ULite SOM as Evaluation Kit

---

Virtual Machine

DESK-MX6UL-L contains all the required software and documentation to start developing Linux application on the AXEL ULite platform. In particular, DESK-MX6UL-L provides a virtual machine, called DVDK, with the following features:

• VirtualBox virtual machine (.OVA archive)
• based on Lubuntu 20.04 LTS (64-bit version)
• pre-installed VirtualBox Guest Additions
• LXDE desktop environment
• boot disk with the distro and pre-configured basic Linux services:
  • TFTP: with base directory /srv/tftp/
  • NFS: configured through the /etc/exports file
• secondary disk containing source code and tools:
  • bootloader (u-boot) source tree cloned from DAVE Embedded Systems public git repository
  • Linux kernel source tree cloned from DAVE Embedded Systems public git repository
  • external pre-built toolchain
  • Yocto BSP for AXEL ULite SOM
• pre-installed Yocto-based root file systems with setup scripts, makefiles, example applications, ...
• administrator account (dvdk) with autologin. Please note that the user account credentials are provided with the development kit (you can find them in the README file contained in the sw/dvdk folder of the kit distribution)
  • user: dvdk
  • password: dvdk

Please note that u-boot and kernel source trees are derived from the official trees released by NXP/Freescale; these trees have been customized to add support for the AXEL ULite SOM.

Guest Addictions

Guest Addictions installation may fail if the VirtualBox version is different from the VM linux kernel version.

In case of VBox error message:

Error: kernel headers not found

as suggested here, install the correct kernel header using the following command:

sudo apt-get install linux-headers-`uname -r`

and the run the Guest Addictions install

dvdk@vagrant:/media/dvdk/VBox_GAs_6.1.18$ sudo ./VBoxLinuxAdditions.run
Verifying archive integrity... All good.
Uncompressing VirtualBox 6.1.18 Guest Additions for Linux........
VirtualBox Guest Additions installer
Removing installed version 6.1.16 of VirtualBox Guest Additions...
update-initramfs: Generating /boot/initrd.img-4.4.0-197-generic
Copying additional installer modules ...
Installing additional modules ...
VirtualBox Guest Additions: Starting.
VirtualBox Guest Additions: Building the VirtualBox Guest Additions kernel 
modules.  This may take a while.
VirtualBox Guest Additions: To build modules for other installed kernels, run
VirtualBox Guest Additions:   /sbin/rcvboxadd quicksetup <version>
VirtualBox Guest Additions: or
VirtualBox Guest Additions:   /sbin/rcvboxadd quicksetup all
VirtualBox Guest Additions: Building the modules for kernel 4.4.0-197-generic.
update-initramfs: Generating /boot/initrd.img-4.4.0-197-generic
W: mdadm: /etc/mdadm/mdadm.conf defines no arrays.
VirtualBox Guest Additions: Running kernel modules will not be replaced until 
the system is restarted
dvdk@vagrant:/media/dvdk/VBox_GAs_6.1.18$ 

Host setup

Since your OS, where VirtualBox is running, can be different compared to the version that we using, in case of an error we suggest updating VirtualBox to the latest release patch. For example, if we used virtualbox-6.1_6.1.18-142142 version of VirtualBox to test MVM but this does not work for you, update VirtualBox to the latest version of virtualbox-6.1_6.1.XX

As stated previously, AXEL ULite SOM host tools are based on a Managed Virtual Machine, we used virtualbox-6.1_6.1.18-142142 to perform virtual machine. MVM OVA files can be downloaded here. For accessing DESK Reserved area please contact our helpdesk support channel

To install it, please refer to this page.

It is worth remembering that access to git repositories is required to download target source code. To enable it, please refer to this page.

Toolchain installation

The DESK-MX6UL-L Ubuntu 20.04 Virtual Machine - used up to DESK-MX6UL-L-4.x.x release - is still valid.

This means that only the toolchain needs to be installed in the VM for building the new BSP.

• download the toolchain from the DESK-MX6UL-L-6.0.0 mirror server

dvdk@vagrant:~/desk-mx-l$ wget https://mirror.dave.eu/desk-mx-l/desk-mx6ul-l-6.0.0/fsl-imx-fb-glibc-x86_64-core-image-minimal-cortexa7t2hf-neon-desk-mx6ul-axelulite-toolchain-6.6-scarthgap.sh
...
...
dvdk@vagrant:~/desk-mx-l$ 

• launch the installation downloaded file

dvdk@vagrant:~/desk-mx-l$ ./fsl-imx-fb-glibc-x86_64-core-image-minimal-cortexa7t2hf-neon-desk-mx6ul-axelulite-toolchain-6.6-scarthgap.sh 
NXP i.MX Release Distro SDK installer version 6.6-scarthgap
===========================================================
Enter target directory for SDK (default: /opt/fsl-imx-fb/6.6-scarthgap): 
You are about to install the SDK to "/opt/fsl-imx-fb/6.6-scarthgap". Proceed [Y/n]? Y
Extracting SDK..............................................................................................................done
Setting it up...done
SDK has been successfully set up and is ready to be used.
Each time you wish to use the SDK in a new shell session, you need to source the environment setup script e.g.
 $ . /opt/fsl-imx-fb/6.6-scarthgap/environment-setup-cortexa7t2hf-neon-poky-linux-gnueabi
dvdk@vagrant:~/desk-mx-l$ 

• when required, source the environment for enabling the cross-toolchain to properly build ARM application

dvdk@vagrant:~/desk-mx-l$ source /opt/fsl-imx-fb/6.6-scarthgap/environment-setup-cortexa7t2hf-neon-poky-linux-gnueabi
dvdk@vagrant:~/desk-mx-l$ echo $CC
arm-poky-linux-gnueabi-gcc -mthumb -mfpu=neon -mfloat-abi=hard -mcpu=cortex-a7 -fstack-protector-strong -O2 -D_FORTIFY_SOURCE=2 -Wformat -Wformat-security -Werror=format-security -D_TIME_BITS=64 -D_FILE_OFFSET_BITS=64 --sysroot=/opt/fsl-imx-fb/6.6-scarthgap/sysroots/cortexa7t2hf-neon-poky-linux-gnueabi
dvdk@vagrant:~/desk-mx-l$ 

---

ConfigID and UniqueID

ConfigID

ConfigID is a new feature of DAVE Embedded Systems products. Its main purpose is providing an automatic mechanism for the identification of the product model and configuration.

With ConfigID, we aim at:

• completing the hardware configuration information that the software can't normally auto-detect (i.e. RAM chip version,...), implementing a dedicated reliable detect procedure
• when required, overriding the auto-detected hardware configuration information

When implemented, this mechanism allows for:

• initializing in the proper way the hardware platform, based on the specific features and parameters of the product, using a common software base (eg: a typical case is the SDRAM controller parameters, which must be configured by U-Boot depending on the particular memory chip, which can be different for the various SOM models)
• getting the complete hardware configuration (combining ConfigID with the information collectable at runtime) of a product deployed on the field

In simple words, model identification means the capability of reading a numerical code, stored in an available device (SOC's OTP , I2C EEPROM, 1-wire memories, protected NOR flash, etc.)

There are two ConfigIDs:

• SOM ConfigID: which reflects the characteristics of the SOM (stored on the SOM itself)
• Carrier Board (CB) ConfigID: which reflects the characteristics of the carrier board that hosts the SOM (stored on the carrier board itself and read by the SOM at boot time)

UniqueID

An additional attribute is UniqueID, which is a read-only code which univocally identifies a single product and is used for traceability.

It is worth remembering that ConfigID and UniqueID are independent from product serial number.

Customer's action

DAVE Embedded Systems recommends to be up-to-date with Official SOM's BSPs for taking advantages of ConfigID/UniqueId features: this is the only required action.

• ConfigID advantage: to allow U-Boot bootloader to be executed only with the correct configuration (if the U-Boot loaded is not the proper one, it may stop execution avoiding incorrect behaviour)
• UniqueID advantage: to trace univocally each individual SOMs and, in turn, all the on-the-field equipments

ConfigID values

ConfigID is a N-bit (typically N>8) signed integer, that can have the following values:

• < 0: error
  • -1: not initialized
• = 0: ConfigID legacy
  • for prototypes (ConfigID not yet defined) or for products manufactured before the introduction of the ConfigID feature
• > 0: valid ConfigID
  • values are reported accordingly with the specific product table

Hardware implementations of the ConfigID

The following paragraphs briefly describe the available solutions for storing the ConfigID.

OTP on the SOC

Some SOCs provides programmable OTPs (eg. for security, MAC address, boot modes, etc). Usually, some of these are general purpose registers and can be managed by the user.

This is the ideal implementation, because:

• ConfigID is stored in the most important component of the SOM
• the component that hosts the ConfigID is NOT optional
• typically, a very selective lock can be forced. In general, for reliability and/or security reasons, OTP areas used to store ConfigIDs may be locked during the manufacturing process.

OTP 1-wire memory

This implementation requires a 1-wire memory chip.

I2C Eeprom

This implementation requires connecting an EEPROM to an I2C bus of the SOC. Moreover, routing a write protect pin to the SOM connector is required.

NOR Flash SPI

This implementation requires a NOR flash connected to the SPI bus of the SOC.

DAVE Embedded Systems' hardware implementation

DAVE's SOCs implement the ConfigID feature depending on hardware Capabilities of the SOCs. The following list shows the priority used for its implementation:

1. OTPs
   1. example: AXEL family processor (i.MX6) implements ConfigID using processor's OTP
   2. AXEL uses GP1 eFuse register to store ConfigID
2. NOR Flash SPI
   1. example: DIVA family processor (AM335x) implements ConfigID using NOR SPI (if present)
   2. DIVA and BORA use the first 32bytes OTP block on NOR SPI to store ConfigID (and its CRC32), UniqueID (and its CRC32)
3. I2C Eeprom
   1. example: DIVA family processor (AM335x) or BORA Lite processor (ZYNQ) implements ConfigID using I2C Eeprom when NOR SPI is not present (module boots from NAND or SD)
   2. DIVA and BORA Lite use the first 32bytes on I2C EPROM to store ConfigID (and its CRC32), UniqueID (and its CRC32)
4. 1-wire
   1. example: latest AXEL Lite, AXEL ULite and BORA/BORA Xpress/BORA Lite Evaluation Kits implement CB ConfigID using the onboard 1-wire device (DS2431)

Software implementation

U-Boot

u-boot integrates the software routines for reading and displaying the ConfigID: hereunder an example of SOM ConfigID at startup:

U-Boot 2013.04-00010-gcb05b30 (Jun 26 2015 - 12:49:26)-xelk-2.1.0

CPU:   Freescale i.MX6Q rev1.5 at 792 MHz
CPU:   Temperature 47 C, limits (-40 C, 125 C), calibration data: 0xc0
Reset cause: POR
Environment: SPI Flash
I2C:   ready
DRAM:  2 GiB
Now running in RAM - U-Boot at: 8ff35000
NAND:  512 MiB
MMC:   FSL_SDHC: 0, FSL_SDHC: 1
SF: Detected S25FL256S with page size 64 KiB, total 32 MiB
In:    serial
Out:   serial
Err:   serial
Power: found PFUZE100 (devid=10, revid=21)
SOM ConfigID#: 00000003
SOM UniqueID#: df646299:0b0579d4

For accessing these information on Linux procfs, the device tree must be modified (using u-boot fdt command): for example:

DIVA# setenv fdtfixup 'fdt addr ${fdtaddr}; run fdtfixup_configid'
DIVA# setenv fdtfixup_configid 'fdt set / som_configid ${som_configid#}; fdt set / som_uniqueid ${som_uniqueid#}; fdt set / cb_configid ${cb_configid#}; fdt set / cb_uniqueid ${cb_uniqueid#}'

Linux

It is possible to read the ConfigID/UniqueID via procfs; for example:

root@axel-lite:~# cat /proc/device-tree/som/configid && echo
00000003
root@axel-lite:~# cat /proc/device-tree/som/uniqueid && echo
df646299:0b0579d4
root@axel-lite:~#

Legacy device tree, has a sightly different procfs structure:

root@axel-lite:~# cat /proc/device-tree/som_configid && echo
00000003
root@axel-lite:~# cat /proc/device-tree/som_uniqueid && echo
df646299:0b0579d4
root@axel-lite:~#

A real case example of ConfigID benefit

The ConfigID benefit is clear when:

• there is a number of products deployed on the field
• the products deployed on the field needs a SW update

The ideal scenario is that all products are equal and there are no differences on the Bill Of Material (BOM):

• All products have the same BOM with a single Config ID
• 

  ConfigID A

• 

  ConfigID A

• 

  ConfigID A

• 

  ConfigID A

• 

  ConfigID A

• 

  ConfigID A

In this case there are no problems to deploy a new SW update on the field: all products have the same HW configuration, then the same SW configuration.

Unfortunately, this is an ideal scenario. The reality is that:

• component obsolescence
• product shortage
• second source strategies

force to have an on-the-field different version of product (with same functionalities but with different HW configuration) which doesn't permit to realize what proposed in the ideal case.

The usage of the ConfigID technique, allows the running SW to identify the underlying HW configuration and automatically adapt the BSP (i.e. the driver layer) to properly use the HW subsystems: this, maintaining the overall product features identical to the final User point-of-view.

• All products are similar BUT there are different Config ID between the 2 product versions
• 

  ConfigID A

• 

  ConfigID A

• 

  ConfigID B

• 

  ConfigID B

• 

  ConfigID A

• 

  ConfigID B

With a scenario, like the one described above, if you would like to update the SW you need to implement a strategy for understanding what platform version is going to be updated. The Config ID is used exactly for this goal.

The ConfigID provides to the software update routine the information on which product version is so the update can be adapted to the exact product version.

In this way, you can distribute one single version of the software update which will automatically adapt itself to the currently running platform.

How to handle After Sales with Config ID

One of the mos common questions about Config ID is how to handle the Config ID issue. Below is described with an example how to handle it.

This product is returned from the field with a problem on the display:

Config ID A

After Sales Dept analizes the product and decide to substitute the display. The problem is that the existing display is not available - because of is End Of Life (EOL) - and it is required to move to a different display: in the product a different Config ID will be written because of the 2 displays requires a dedicated SW version and cannot be distinguished automatically during the startup. The final result is to have the similar product:

Config ID B

As indicated, the new display requires a different Config ID (from A to B) so it can be updated with an easy software routine before start the SW update. This Config ID update routine can be implemented in manufacturing facility typically using a dedicated USB pen drive which modify the saved ConfigID to the new one depending on the storage memory in use

ConfigID

This article describes how the ConfigID is implemented in the products supported by the DESK-MX6UL-L Linux Kit.

AXEL ULite

As AXEL ULite is a system-on-module (SOM), the typical mechanism described here is used.

Moreover, a system is composed of the combination of a SOM and a carrier board. In this case, two ConfigIDs are used to identify the actual board configuration like it was a SOM+carrier board system.

For the sake of simplicity, the first ConfigID is denoted as SOM ConfigID, while the second one is denoted as CB ConfigID:

...
SOM ConfigID#: 00000014
SOM UniqueID#: ee6ac309:171411d4
CB ConfigID#: 0000003a
CB UniqueID#: 00000000:00000000
Board: MX6UL AXEL ULite rev.A on SDV04
...

Generally speaking:

• SOM ConfigID is used to identify the configuration of the basic features of the SOM
• CB ConfigID is used to identify the peripherals and the I/O interfaces.

NXP silicon manufacturer guarantees that processors UIDs (a.k.a. SOM UniqueID# on DESK-MX6UL-L) to be unique over the whole MX6UL family

---

Booting from NFS

This configuration is very helpful during the software development (both for kernel and applications). The kernel image is downloaded via TFTP while the root file system is remotely mounted via NFS from the host. It is assumed that the development host:

• is connected with the target host board through an Ethernet LAN
• exports the directory containing the root file system for the target through the NFS server
• runs a TFTP server.
• has a proper subnet IP address

net_nfs configuration

DESK-MX6UL-L Virtual Machine is properly configured for the TFTP and NFS debug.

In any case, some variables has to be configured on the target and the VM itself has to be configured for respect to the network environment.

Host (Virtual Machine) configuration

The DESK-MX6UL-L Virtual Machine has the tftp and nfs services already running. Optionally, their configuration has to be changed according to the network configuration where the target is connected to.

Check and properly configure the items describe in VirtualBox Network Configuration

root file system

First of all, extract the new root file system in a proper directory in the VM:

dvdk@vagrant:~/desk-mx-l/rfs$ wget https://mirror.dave.eu/desk-mx-l/desk-mx6ul-l-6.0.0/dave-image-minimal-desk-mx6ul-axelulite-fsl-imx-fb.tar.bz2
--2025-12-17 11:04:45--  https://mirror.dave.eu/desk-mx-l/desk-mx6ul-l-6.0.0/dave-image-minimal-desk-mx6ul-axelulite-fsl-imx-fb.tar.bz2
Resolving mirror.dave.eu (mirror.dave.eu)... 84.46.251.143
Connecting to mirror.dave.eu (mirror.dave.eu)|84.46.251.143|:443... connected.
HTTP request sent, awaiting response... 200 OK
Length: 137695245 (131M) [application/x-bzip2]
Saving to: ‘dave-image-minimal-desk-mx6ul-axelulite-fsl-imx-fb.tar.bz2’

dave-image-minimal-desk-mx6ul-axelulite-fsl-imx 100%[====================================================================================================>] 131.32M  11.3MB/s    in 13s     

2025-12-17 11:04:59 (9.93 MB/s) - ‘dave-image-minimal-desk-mx6ul-axelulite-fsl-imx-fb.tar.bz2’ saved [137695245/137695245]

dvdk@vagrant:~/desk-mx-l/rfs$ mkdir desk-mx6ul-l-6.0.0
dvdk@vagrant:~/desk-mx-l/rfs$ sudo tar jxpf dave-image-minimal-desk-mx6ul-axelulite-fsl-imx-fb.tar.bz2 -C desk-mx6ul-l-6.0.0

then create a proper link to the new rfs:

dvdk@vagrant:~/desk-mx-l/rfs$ sudo rm desk-mx6ul-l
dvdk@vagrant:~/desk-mx-l/rfs$ sudo ln -s desk-mx6ul-l-6.0.0 desk-mx6ul-l

Target configuration

The IP address for server and target should be configured: an example (for a network subnet 192.168.0.x)

=> setenv serverip 192.168.0.125
=> setenv ipaddr 192.168.0.90

• serverip is the IP address of the host machine running the tftp/nfs server
• ipaddr is the IP address of the target

The kernel and device tree files has to be selected

=> setenv bootfile desk-mx-l/uImage
=> setenv fdtfile desk-mx-l/imx6ul-axelulite-cb003a.dtb

finally, the root file system directory on the Virtual Machine should be configured for let the kernel to find the INIT

=> setenv rootpath /home/dvdk/desk-mx-l/rfs/desk-mx6ul-l/

To run this configuration just issue the net_nfs command which firstly download the kernel and device tree using the tftp protocol

U-Boot SPL 2024.04-desk-mx6ul-l-6.0.0+fslc+g4abe9e61e05+p0 (Dec 09 2025 - 13:27:10 +0000)
SOM ConfigID#: 0000001d
Trying to boot from MMC1


U-Boot 2024.04-desk-mx6ul-l-6.0.0+fslc+g4abe9e61e05+p0 (Dec 09 2025 - 13:27:10 +0000)

CPU:   Freescale i.MX6UL rev1.2 528 MHz (running at 396 MHz)
CPU:   Industrial temperature grade (-40C to 105C) at 54C
Reset cause: POR
Model: AxelULite on SFCZG
DRAM:  512 MiB
Relocating to 9ee53000, new gd at 9de52ea0, sp at 9de4ac40
Core:  60 devices, 23 uclasses, devicetree: separate
NAND:  2048 MiB
MMC:   FSL_SDHC: 0
Loading Environment from MMC... OK
[*]-Video Link 0 (800 x 480)
        [0] lcdif@21c8000, video
In:    serial
Out:   serial
Err:   serial
SEC0:  RNG instantiated
switch to partitions #0, OK
mmc0 is current device (SD)
SOM ConfigID#: 0000001d
SOM UniqueID#: ee6ac309:184729d4
CB ConfigID#: 0000003a
CB UniqueID#: 00000000:00000000
Board: MX6UL AXEL ULite rev.A on SDV04
Net:   eth0: ethernet@2188000 [PRIME]
Fastboot: Normal
Normal Boot
Hit any key to stop autoboot:  0
=> run net_nfs
Using ethernet@2188000 device
TFTP from server 192.168.0.125; our IP address is 192.168.0.90
Filename 'desk-mx6ul-l/uImage'.
Load address: 0x80800000
Loading: #################################################################
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         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
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         #################
         292 KiB/s
done
Bytes transferred = 10401080 (9eb538 hex)
Using ethernet@2188000 device
TFTP from server 192.168.0.125; our IP address is 192.168.0.90
Filename 'desk-mx6ul-l/imx6ul-axelulite-cb003a.dtb'.
Load address: 0x83000000
Loading: #######
         227.5 KiB/s
done
Bytes transferred = 32964 (80c4 hex)
Working FDT set to 83000000
Working FDT set to 83000000
Working FDT set to 83000000
FDT: override 'som_uniqueid' with 'ee6ac309:184729d4'
FDT: override 'cb_uniqueid' with '00000000:00000000'
## Booting kernel from Legacy Image at 80800000 ...
   Image Name:   Linux-6.6.52-desk-mx6ul-l-6.0.0-
   Image Type:   ARM Linux Kernel Image (uncompressed)
   Data Size:    10401016 Bytes = 9.9 MiB
   Load Address: 80008000
   Entry Point:  80008000
   Verifying Checksum ... OK
## Flattened Device Tree blob at 83000000
   Booting using the fdt blob at 0x83000000
Working FDT set to 83000000
   Loading Kernel Image to 80008000
   Using Device Tree in place at 83000000, end 8300bfff
Working FDT set to 83000000

Starting kernel ...

[    0.000000] Booting Linux on physical CPU 0x0
[    0.000000] Linux version 6.6.52-desk-mx6ul-l-6.0.0-gabab4e2fb8c4 (oe-user@oe-host) (arm-poky-linux-gnueabi-gcc (GCC) 13.3.0, GNU ld (GNU Binutils) 2.42.0.20240723) #1 SMP PREEMPT Tue Dec  9 13:39:09 UTC 2025
[    0.000000] CPU: ARMv7 Processor [410fc075] revision 5 (ARMv7), cr=10c5387d
[    0.000000] CPU: div instructions available: patching division code
[    0.000000] CPU: PIPT / VIPT nonaliasing data cache, VIPT aliasing instruction cache
[    0.000000] OF: fdt: Machine model: AxelULite on SFCZG
[    0.000000] Memory policy: Data cache writealloc
[    0.000000] cma: Reserved 32 MiB at 0x9e000000 on node -1
[    0.000000] Zone ranges:
[    0.000000]   Normal   [mem 0x0000000080000000-0x000000009fffffff]
[    0.000000]   HighMem  empty
[    0.000000] Movable zone start for each node
[    0.000000] Early memory node ranges
[    0.000000]   node   0: [mem 0x0000000080000000-0x000000009fffffff]
[    0.000000] Initmem setup node 0 [mem 0x0000000080000000-0x000000009fffffff]
[    0.000000] percpu: Embedded 12 pages/cpu s18900 r8192 d22060 u49152
[    0.000000] Kernel command line: root=/dev/nfs ip=192.168.0.90:192.168.0.125:192.168.0.254:255.255.255.0::eth0:off panic=1 nfsroot=192.168.0.125:/home/dvdk/desk-mx-l/rfs/desk-mx6ul-l,nfsvers=3,tcp fec_mac=70:b3:d5:3e:a2:ae console=ttymxc0,115200 vmalloc=400M panic=5 mtdparts=gpmi-nand:2M(nand-SPL),6M(nand-uboot),1M(nand-env1),1M(nand-env2),1M(nand-fdt),1M(nand-spare),12M(nand-kernel),4M(nand-splash),-(nand-ubi);spi0.0:64k(spi-SPL),960k(spi-uboot),256k(spi-env1),256k(spi-env2),512k(spi-dtb),11M(spi-kernel),2M(spi-splash),-(spi-free)
[    0.000000] Unknown kernel command line parameters "fec_mac=70:b3:d5:3e:a2:ae", will be passed to user space.
[    0.000000] Dentry cache hash table entries: 65536 (order: 6, 262144 bytes, linear)
[    0.000000] Inode-cache hash table entries: 32768 (order: 5, 131072 bytes, linear)
[    0.000000] Built 1 zonelists, mobility grouping on.  Total pages: 129920
[    0.000000] mem auto-init: stack:all(zero), heap alloc:off, heap free:off
[    0.000000] Memory: 463960K/524288K available (14336K kernel code, 1378K rwdata, 4520K rodata, 1024K init, 425K bss, 27560K reserved, 32768K cma-reserved, 0K highmem)
[    0.000000] SLUB: HWalign=64, Order=0-3, MinObjects=0, CPUs=1, Nodes=1
[    0.000000] rcu: Preemptible hierarchical RCU implementation.
[    0.000000] rcu:     RCU event tracing is enabled.
[    0.000000] rcu:     RCU restricting CPUs from NR_CPUS=4 to nr_cpu_ids=1.
[    0.000000]  Trampoline variant of Tasks RCU enabled.
[    0.000000] rcu: RCU calculated value of scheduler-enlistment delay is 10 jiffies.
[    0.000000] rcu: Adjusting geometry for rcu_fanout_leaf=16, nr_cpu_ids=1
[    0.000000] NR_IRQS: 16, nr_irqs: 16, preallocated irqs: 16
[    0.000000] rcu: srcu_init: Setting srcu_struct sizes based on contention.
[    0.000000] Switching to timer-based delay loop, resolution 41ns
[    0.000003] sched_clock: 32 bits at 24MHz, resolution 41ns, wraps every 89478484971ns
[    0.000042] clocksource: mxc_timer1: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 79635851949 ns
[    0.003125] Console: colour dummy device 80x30
[    0.003215] Calibrating delay loop (skipped), value calculated using timer frequency.. 48.00 BogoMIPS (lpj=240000)
[    0.003255] CPU: Testing write buffer coherency: ok
[    0.003356] pid_max: default: 32768 minimum: 301
[    0.003766] Mount-cache hash table entries: 1024 (order: 0, 4096 bytes, linear)
[    0.003810] Mountpoint-cache hash table entries: 1024 (order: 0, 4096 bytes, linear)
[    0.006051] CPU0: update cpu_capacity 1024
[    0.006093] CPU0: thread -1, cpu 0, socket 0, mpidr 80000000
[    0.009529] RCU Tasks: Setting shift to 0 and lim to 1 rcu_task_cb_adjust=1.
[    0.009974] Setting up static identity map for 0x80100000 - 0x80100060
[    0.010621] rcu: Hierarchical SRCU implementation.
[    0.010643] rcu:     Max phase no-delay instances is 1000.
[    0.012240] smp: Bringing up secondary CPUs ...
[    0.012309] smp: Brought up 1 node, 1 CPU
[    0.012339] SMP: Total of 1 processors activated (48.00 BogoMIPS).
[    0.012362] CPU: All CPU(s) started in SVC mode.
[    0.013652] devtmpfs: initialized
[    0.026781] Duplicate name in lcdif@21c8000, renamed to "display#1"
[    0.031593] VFP support v0.3: implementor 41 architecture 2 part 30 variant 7 rev 5
[    0.032306] clocksource: jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 19112604462750000 ns
[    0.032367] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
[    0.034929] pinctrl core: initialized pinctrl subsystem
[    0.038689] NET: Registered PF_NETLINK/PF_ROUTE protocol family
[    0.057843] DMA: preallocated 256 KiB pool for atomic coherent allocations
[    0.061425] thermal_sys: Registered thermal governor 'step_wise'
[    0.061630] cpuidle: using governor menu
[    0.062180] CPU identified as i.MX6UL, silicon rev 1.2
[    0.062212] Use WDOG1 as reset source
[    0.075771] platform soc: Fixed dependency cycle(s) with /soc/bus@2000000/gpc@20dc000
[    0.099974] platform 20e0000.pinctrl: Fixed dependency cycle(s) with /soc/bus@2000000/pinctrl@20e0000/imx6ul-axelulite/gpioext-grp
[    0.117262] No ATAGs?
[    0.117406] hw-breakpoint: found 5 (+1 reserved) breakpoint and 4 watchpoint registers.
[    0.117439] hw-breakpoint: maximum watchpoint size is 8 bytes.
[    0.120386] imx6ul-pinctrl 20e0000.pinctrl: initialized IMX pinctrl driver
[    0.127467] imx mu driver is registered.
[    0.128376] imx rpmsg driver is registered.
[    0.131951] kprobes: kprobe jump-optimization is enabled. All kprobes are optimized if possible.
[    0.136368] gpio gpiochip0: Static allocation of GPIO base is deprecated, use dynamic allocation.
[    0.141972] gpio gpiochip1: Static allocation of GPIO base is deprecated, use dynamic allocation.
[    0.147349] gpio gpiochip2: Static allocation of GPIO base is deprecated, use dynamic allocation.
[    0.153042] gpio gpiochip3: Static allocation of GPIO base is deprecated, use dynamic allocation.
[    0.158548] gpio gpiochip4: Static allocation of GPIO base is deprecated, use dynamic allocation.
[    0.173103] SCSI subsystem initialized
[    0.174619] usbcore: registered new interface driver usbfs
[    0.174751] usbcore: registered new interface driver hub
[    0.174876] usbcore: registered new device driver usb
[    0.178939] i2c i2c-0: IMX I2C adapter registered
[    0.180972] i2c i2c-1: IMX I2C adapter registered
[    0.183440] mc: Linux media interface: v0.10
[    0.183680] videodev: Linux video capture interface: v2.00
[    0.183880] pps_core: LinuxPPS API ver. 1 registered
[    0.183896] pps_core: Software ver. 5.3.6 - Copyright 2005-2007 Rodolfo Giometti <giometti@linux.it>
[    0.183969] PTP clock support registered
[    0.188012] MIPI CSI2 driver module loaded
[    0.188148] Advanced Linux Sound Architecture Driver Initialized.
[    0.190512] Bluetooth: Core ver 2.22
[    0.190656] NET: Registered PF_BLUETOOTH protocol family
[    0.190674] Bluetooth: HCI device and connection manager initialized
[    0.190708] Bluetooth: HCI socket layer initialized
[    0.190729] Bluetooth: L2CAP socket layer initialized
[    0.190779] Bluetooth: SCO socket layer initialized
[    0.192073] vgaarb: loaded
[    0.193433] clocksource: Switched to clocksource mxc_timer1
[    0.194190] VFS: Disk quotas dquot_6.6.0
[    0.194313] VFS: Dquot-cache hash table entries: 1024 (order 0, 4096 bytes)
[    0.225816] NET: Registered PF_INET protocol family
[    0.226465] IP idents hash table entries: 8192 (order: 4, 65536 bytes, linear)
[    0.230497] tcp_listen_portaddr_hash hash table entries: 512 (order: 0, 4096 bytes, linear)
[    0.230580] Table-perturb hash table entries: 65536 (order: 6, 262144 bytes, linear)
[    0.230619] TCP established hash table entries: 4096 (order: 2, 16384 bytes, linear)
[    0.230726] TCP bind hash table entries: 4096 (order: 4, 65536 bytes, linear)
[    0.230992] TCP: Hash tables configured (established 4096 bind 4096)
[    0.231213] UDP hash table entries: 256 (order: 1, 8192 bytes, linear)
[    0.231291] UDP-Lite hash table entries: 256 (order: 1, 8192 bytes, linear)
[    0.231711] NET: Registered PF_UNIX/PF_LOCAL protocol family
[    0.233097] RPC: Registered named UNIX socket transport module.
[    0.233134] RPC: Registered udp transport module.
[    0.233147] RPC: Registered tcp transport module.
[    0.233158] RPC: Registered tcp-with-tls transport module.
[    0.233170] RPC: Registered tcp NFSv4.1 backchannel transport module.
[    0.237236] PCI: CLS 0 bytes, default 64
[    0.238974] hw perfevents: enabled with armv7_cortex_a7 PMU driver, 5 counters available
[    0.242979] Bus freq driver module loaded
[    0.245925] Initialise system trusted keyrings
[    0.246685] workingset: timestamp_bits=14 max_order=17 bucket_order=3
[    0.248604] NFS: Registering the id_resolver key type
[    0.248736] Key type id_resolver registered
[    0.248754] Key type id_legacy registered
[    0.248884] nfs4filelayout_init: NFSv4 File Layout Driver Registering...
[    0.248906] nfs4flexfilelayout_init: NFSv4 Flexfile Layout Driver Registering...
[    0.249018] jffs2: version 2.2. (NAND) © 2001-2006 Red Hat, Inc.
[    0.249889] fuse: init (API version 7.39)
[    0.687363] Key type asymmetric registered
[    0.687402] Asymmetric key parser 'x509' registered
[    0.687568] io scheduler mq-deadline registered
[    0.687591] io scheduler kyber registered
[    0.687659] io scheduler bfq registered
[    0.708004] imx-sdma 20ec000.sdma: Direct firmware load for imx/sdma/sdma-imx6q.bin failed with error -2
[    0.708053] imx-sdma 20ec000.sdma: Falling back to sysfs fallback for: imx/sdma/sdma-imx6q.bin
[    0.712754] mxs-dma 1804000.dma-apbh: initialized
[    0.726484] pfuze100-regulator 0-0008: Full layer: 1, Metal layer: 1
[    0.727362] pfuze100-regulator 0-0008: FAB: 0, FIN: 0
[    0.727401] pfuze100-regulator 0-0008: pfuze3000 found.
[    0.734491] 2020000.serial: ttymxc0 at MMIO 0x2020000 (irq = 201, base_baud = 5000000) is a IMX
[    0.734733] printk: console [ttymxc0] enabled
[    1.641872] 21ec000.serial: ttymxc2 at MMIO 0x21ec000 (irq = 202, base_baud = 5000000) is a IMX
[    1.660276] imx sema4 driver is registered.
[    1.706529] brd: module loaded
[    1.727736] loop: module loaded
[    1.741305] nand: device found, Manufacturer ID: 0x2c, Chip ID: 0x48
[    1.747893] nand: Micron MT29F16G08ABABAWP
[    1.752027] nand: 2048 MiB, SLC, erase size: 512 KiB, page size: 4096, OOB size: 224
[    1.761110] Scanning device for bad blocks
[    2.185888] 9 cmdlinepart partitions found on MTD device gpmi-nand
[    2.192126] Creating 9 MTD partitions on "gpmi-nand":
[    2.197271] 0x000000000000-0x000000200000 : "nand-SPL"
[    2.204248] 0x000000200000-0x000000800000 : "nand-uboot"
[    2.211136] 0x000000800000-0x000000900000 : "nand-env1"
[    2.218069] 0x000000900000-0x000000a00000 : "nand-env2"
[    2.224965] 0x000000a00000-0x000000b00000 : "nand-fdt"
[    2.231662] 0x000000b00000-0x000000c00000 : "nand-spare"
[    2.238652] 0x000000c00000-0x000001800000 : "nand-kernel"
[    2.245805] 0x000001800000-0x000001c00000 : "nand-splash"
[    2.252727] 0x000001c00000-0x000080000000 : "nand-ubi"
[    2.263965] gpmi-nand 1806000.nand-controller: driver registered.
[    2.274958] spinor@0 enforce active low on GPIO handle
[    2.283655] spi-nor spi0.0: is25lp128 (16384 Kbytes)
[    2.288821] 8 cmdlinepart partitions found on MTD device spi0.0
[    2.294939] Creating 8 MTD partitions on "spi0.0":
[    2.299779] 0x000000000000-0x000000010000 : "spi-SPL"
[    2.306586] 0x000000010000-0x000000100000 : "spi-uboot"
[    2.313379] 0x000000100000-0x000000140000 : "spi-env1"
[    2.320231] 0x000000140000-0x000000180000 : "spi-env2"
[    2.327075] 0x000000180000-0x000000200000 : "spi-dtb"
[    2.333795] 0x000000200000-0x000000d00000 : "spi-kernel"
[    2.340703] 0x000000d00000-0x000000f00000 : "spi-splash"
[    2.347700] 0x000000f00000-0x000001000000 : "spi-free"
[    2.360388] tun: Universal TUN/TAP device driver, 1.6
[    2.366451] CAN device driver interface
[    2.376099] pps pps0: new PPS source ptp0
[    2.388442] fec 2188000.ethernet eth0: registered PHC device 0
[    2.395249] e1000e: Intel(R) PRO/1000 Network Driver
[    2.400258] e1000e: Copyright(c) 1999 - 2015 Intel Corporation.
[    2.407355] usbcore: registered new device driver r8152-cfgselector
[    2.414046] usbcore: registered new interface driver r8152
[    2.419666] usbcore: registered new interface driver lan78xx
[    2.425639] usbcore: registered new interface driver asix
[    2.431162] usbcore: registered new interface driver ax88179_178a
[    2.437456] usbcore: registered new interface driver cdc_ether
[    2.443457] usbcore: registered new interface driver smsc95xx
[    2.449326] usbcore: registered new interface driver net1080
[    2.455155] usbcore: registered new interface driver cdc_subset
[    2.461189] usbcore: registered new interface driver zaurus
[    2.466964] usbcore: registered new interface driver MOSCHIP usb-ethernet driver
[    2.474535] usbcore: registered new interface driver cdc_ncm
[    2.480351] usbcore: registered new interface driver r8153_ecm
[    2.486613] usbcore: registered new interface driver usb-storage
[    2.501208] ci_hdrc ci_hdrc.0: EHCI Host Controller
[    2.506396] ci_hdrc ci_hdrc.0: new USB bus registered, assigned bus number 1
[    2.543491] ci_hdrc ci_hdrc.0: USB 2.0 started, EHCI 1.00
[    2.549499] usb usb1: New USB device found, idVendor=1d6b, idProduct=0002, bcdDevice= 6.06
[    2.557901] usb usb1: New USB device strings: Mfr=3, Product=2, SerialNumber=1
[    2.565210] usb usb1: Product: EHCI Host Controller
[    2.570120] usb usb1: Manufacturer: Linux 6.6.52-desk-mx6ul-l-6.0.0-gabab4e2fb8c4 ehci_hcd
[    2.578470] usb usb1: SerialNumber: ci_hdrc.0
[    2.585005] hub 1-0:1.0: USB hub found
[    2.588918] hub 1-0:1.0: 1 port detected
[    2.600596] ci_hdrc ci_hdrc.1: EHCI Host Controller
[    2.605806] ci_hdrc ci_hdrc.1: new USB bus registered, assigned bus number 2
[    2.643534] ci_hdrc ci_hdrc.1: USB 2.0 started, EHCI 1.00
[    2.649468] usb usb2: New USB device found, idVendor=1d6b, idProduct=0002, bcdDevice= 6.06
[    2.657857] usb usb2: New USB device strings: Mfr=3, Product=2, SerialNumber=1
[    2.665163] usb usb2: Product: EHCI Host Controller
[    2.670074] usb usb2: Manufacturer: Linux 6.6.52-desk-mx6ul-l-6.0.0-gabab4e2fb8c4 ehci_hcd
[    2.678405] usb usb2: SerialNumber: ci_hdrc.1
[    2.684736] hub 2-0:1.0: USB hub found
[    2.688645] hub 2-0:1.0: 1 port detected
[    2.705754] snvs_rtc 20cc000.snvs:snvs-rtc-lp: registered as rtc0
[    2.711997] snvs_rtc 20cc000.snvs:snvs-rtc-lp: setting system clock to 2025-12-17T10:10:52 UTC (1765966252)
[    2.722944] i2c_dev: i2c /dev entries driver
[    2.738585] mxsfb 21c8000.lcdif: supply lcd not found, using dummy regulator
[    2.746568] cma: cma_alloc: reserved: alloc failed, req-size: 8192 pages, ret: -12
[    2.754402] mxsfb 21c8000.lcdif: Unable to allocate framebuffer memory
[    2.760974] mxsfb 21c8000.lcdif: Failed to initialize fbinfo: -12
[    2.767183] mxsfb: probe of 21c8000.lcdif failed with error -12
[    2.777761] pxp-v4l2 pxp_v4l2: initialized
[    2.791740] Bluetooth: HCI UART driver ver 2.3
[    2.796603] Bluetooth: HCI UART protocol H4 registered
[    2.801789] Bluetooth: HCI UART protocol BCSP registered
[    2.807553] Bluetooth: HCI UART protocol LL registered
[    2.812811] Bluetooth: HCI UART protocol Three-wire (H5) registered
[    2.819350] Bluetooth: HCI UART protocol Marvell registered
[    2.825227] usbcore: registered new interface driver btusb
[    2.833078] sdhci: Secure Digital Host Controller Interface driver
[    2.839543] sdhci: Copyright(c) Pierre Ossman
[    2.844050] sdhci-pltfm: SDHCI platform and OF driver helper
[    2.852782] sdhci-esdhc-imx 2190000.mmc: Got CD GPIO
[    2.864211] usbcore: registered new interface driver usbhid
[    2.870042] usbhid: USB HID core driver
[    2.894412] mmc0: SDHCI controller on 2190000.mmc [2190000.mmc] using ADMA
[    2.912426] NET: Registered PF_LLC protocol family
[    2.920184] NET: Registered PF_INET6 protocol family
[    2.930636] Segment Routing with IPv6
[    2.934887] In-situ OAM (IOAM) with IPv6
[    2.939313] sit: IPv6, IPv4 and MPLS over IPv4 tunneling driver
[    2.947760] NET: Registered PF_PACKET protocol family
[    2.952875] can: controller area network core
[    2.957624] NET: Registered PF_CAN protocol family
[    2.962586] can: raw protocol
[    2.965755] can: broadcast manager protocol
[    2.970095] can: netlink gateway - max_hops=1
[    2.975404] Bluetooth: RFCOMM TTY layer initialized
[    2.980475] Bluetooth: RFCOMM socket layer initialized
[    2.985890] Bluetooth: RFCOMM ver 1.11
[    2.989892] Bluetooth: BNEP (Ethernet Emulation) ver 1.3
[    2.995410] Bluetooth: BNEP filters: protocol multicast
[    3.000839] Bluetooth: BNEP socket layer initialized
[    3.005979] mmc0: host does not support reading read-only switch, assuming write-enable
[    3.014155] Bluetooth: HIDP (Human Interface Emulation) ver 1.2
[    3.020524] mmc0: new high speed SDHC card at address 2145
[    3.027859] mmcblk0: mmc0:2145 APPSD 14.8 GiB
[    3.033856] Bluetooth: HIDP socket layer initialized
[    3.041803] lib80211: common routines for IEEE802.11 drivers
[    3.047891]  mmcblk0: p1 p2
[    3.052935] Key type dns_resolver registered
[    3.087617] Registering SWP/SWPB emulation handler
[    3.141775] Loading compiled-in X.509 certificates
[    3.202365] imx_thermal 20c8000.anatop:tempmon: Industrial CPU temperature grade - max:105C critical:100C passive:95C
[    3.216695] input: gpio-power-fail as /devices/platform/gpio-power-fail/input/input0
[    3.306661] Micrel KSZ8081 or KSZ8091 2188000.ethernet-1:03: attached PHY driver (mii_bus:phy_addr=2188000.ethernet-1:03, irq=POLL)
[    6.405177] fec 2188000.ethernet eth0: Link is Up - 100Mbps/Full - flow control off
[    6.433638] IP-Config: Complete:
[    6.436944]      device=eth0, hwaddr=70:b3:d5:3e:a2:ae, ipaddr=192.168.0.90, mask=255.255.255.0, gw=192.168.0.254
[    6.448186]      host=192.168.0.90, domain=, nis-domain=(none)
[    6.454955]      bootserver=192.168.0.125, rootserver=192.168.0.125, rootpath=
[    6.455625] cfg80211: Loading compiled-in X.509 certificates for regulatory database
[    6.478007] Loaded X.509 cert 'sforshee: 00b28ddf47aef9cea7'
[    6.487700] Loaded X.509 cert 'wens: 61c038651aabdcf94bd0ac7ff06c7248db18c600'
[    6.495456] platform regulatory.0: Direct firmware load for regulatory.db failed with error -2
[    6.504300] platform regulatory.0: Falling back to sysfs fallback for: regulatory.db
[    6.512338] clk: Disabling unused clocks
[    6.517003] ALSA device list:
[    6.520057]   No soundcards found.
...
...

Development

Synchronizing the repository

In DESK-MX6UL-L, the following source trees are clones of the correspondent DAVE Embedded Systems git repositories:

Component	GIT Remote
U-Boot	git@git.dave.eu:desk-mx-l/u-boot-imx.git
Linux kernel	git@git.dave.eu:desk-mx-l/linux-imx.git
Yocto BSP	git@git.dave.eu:desk-mx-l/desk-mx-l-bsp.git

For more information about the access to these repositories, please refer to this link.

Access to DAVE Embedded Systems' git repositories is granted to development kit's owners only. Please refer to this page for detailed instructions on how to get access.

Instructions

The components listed in the table above can be kept in sync and up to date with DAVE Embedded Systems' repositories.

Once the git account has been enabled, the developer can:

• clone the repository with the git clone <git_remote_repository> command
• synchronize a source tree entering the repository directory and launching the git fetch origin command.

Please note that git fetch doesn't merge the commits on the current branch. To do that, the developer should run the git merge command or replace the fetch-merge process with a single git pull command. Please note that the recommended method is the fetch-merge process. For further information on Git, please refer to the official Git Documentation

---

Building U-Boot

Quick reference

Repository Information

URL	git@git.dave.eu:desk-mx-l/u-boot-imx.git
stable branch	desk-mx6ul-l-6.x.x
stable tag	desk-mx6ul-l-6.0.0

U-Boot defconfigs

Platform	SOM ConfigID	CB ConfigID	defconfig
SDV04	-	0x0000003a	mx6uldesk_axelulite_defconfig
SBC Rialto	0x00000022	0x00000090	mx6uldesk_rialto_defconfig

Instructions

It is assumed that the development environment has been set up properly as described here.

• start the Linux development VM and log into the system
• open a terminal window and cd into U-Boot source code

cd ~/desk-mx-l/u-boot

• in case of needs you can update your local repository with the following git command

git pull

• configure the build environment

source /opt/fsl-imx-fb/6.6-scarthgap/environment-setup-cortexa7t2hf-neon-poky-linux-gnueabi

• enter the source tree directory and run the following commands:

for the AXEL Ulite EVK

make mx6uldesk_axelulite_defconfig
make

for the RIALTO SBC platform:

make mx6uldesk_rialto_defconfig
make

NOTE: this is the default configuration suitable for the latest <SOM> target.

The former command selects the default DESK-MX6UL-L configuration suitable for the latest <SOM> targets (for additional defconfig please refer to the U-Boot defconfigs table above), while the latter builds the U-Boot binary image files (SPL and u-boot.img).

Binary files can be copied to the tftp root directory /tftpboot/desk-mx-l/ with the following command:

cp SPL u-boot.img /tftpboot/desk-mx-l/

Please refer to this page for more information on how to update the bootloader on your board.

Building Linux

Quick reference

Repository Information

URL	git@git.dave.eu:desk-mx-l/linux-imx.git
stable branch	desk-mx6ul-l-6.x.x
stable tag	desk-mx6ul-l-6.0.0

Build Information

defconfig	imx_v7_desk_defconfig
Kernel binary	UIMAGE_LOADADDR=0x80008000 uImage
Device trees	Platform	DTB
	SDV04	imx6ul-axelulite-cb003a.dtb
	SBC Rialto	imx6ul-lynx-som0022-cb0090.dtb

Instructions

It is assumed that the development environment has been set up properly as described here.

• start the Linux development VM and login into the system
• open a terminal window and cd into Linux kernel source code

cd ~/desk-mx-l/linux

• in case of needs you can update your local repository with the following git command

git pull

• configure the build environment

source /opt/fsl-imx-fb/6.6-scarthgap/environment-setup-cortexa7t2hf-neon-poky-linux-gnueabi

• enter the source tree directory and run the following commands:

make imx_v7_desk_defconfig
make UIMAGE_LOADADDR=0x80008000 uImage imx6ul-axelulite-cb003a.dtb imx6ul-lynx-som0022-cb0090.dtb

NOTE: this is the default configuration suitable for latest target.

The former command selects the default DESK-MX6UL-L configuration, while the latter builds the kernel binary image with the required u-boot header and the kernel device tree.

Default Linux kernel configuration can be changed by using the standard menuconfig, xconfig, or gconfig make target. Subsequent builds just require uImage make target to update the binary image. Once the build process is complete, the kernel binary image is stored into the arch/arm/boot/uImage file. Both this file and the kernel device tree can be copied to the tftp root directory /tftpboot/desk-mx-l/ with the following commands:

cp arch/arm/boot/uImage /tftpboot/desk-mx-l/
cp arch/arm/boot/dts/*.dtb /tftpboot/desk-mx-l/

Usually, kernel modules are installed with make modules_install command, but this method installs the modules into the /lib/modules directory of you MVM, which is not what you want.

A better way to deploy kernel modules while cross-compiling is

• generate a .tar.gz archive
• install this archive into the target root file system

User can create such an archive, for example, using the following commands:

make modules
mkdir modules-install
make INSTALL_MOD_PATH=modules-install modules_install

cd modules-install && tar cvzf ../modules.tar.gz . && cd ..

Now copy modules.tar.gz into the target root file system and install them as root with the following command

tar xvzf modules.tar.gz -C /

---

Building the Yocto BSP

Quick reference

Repository Information

Repository	Yocto BSP Layer
URL	git@git.dave.eu:desk-mx-l/meta-desk-mx.git
stable branch	scarthgap
stable tag	desk-mx6ul-l-6.0.0

Build targets

Name	Description
dave-image-minimal	This image include the core image minimal distro

Introduction

As known, in addition to a bootloader and the o.s. kernel, an embedded Linux system needs a root file system to operate. The root file system must contain everything needed to support the Linux system (applications, settings, data, etc.). The root file system is the file system that is contained on the same partition on which the root directory is located. The Linux kernel, at the end of its startup stage, mounts the root file system on the configured root device and finally launches the /sbin/init, the first user space process and "father" of all the other processes. For more information on the Linux filesystem, please refer to http://www.thegeekstuff.com/2010/09/linux-file-system-structure/.

To generate the supported root file systems, the build of the Yocto BSP has to be run. The output of this process is an image containing the U-Boot binary file, the Linux kernel image, and the selected root file system image. The following sections describe in detail how to execute this operation.

For more general information regarding the Yocto build system, please refer to the dedicated category page.

How to build the Yocto BSP images including the U-Boot binary file, the Linux kernel image, and the target root file system image with KAS

The following procedure requires access to the DAVE Embedded Systems' git repositories. Access to such repositories is granted to the development kit's owners only. Please refer to this page for detailed instructions on how to get it.

This process requires a lot of hardware resources in terms of disk storage, RAM, and processing power. For this reason, it also is recommended to consider the use of a physical machine. For more details on this topic, please refer to the NXP documentation on this BSP, i.e. the i.MX Yocto Project User's Guide, which talks about the host setup for the Yocto build system.

Initialize the build environment

DESK-MX6UL-L-6.x.x Yocto build system uses the kas container feature to ensure reproducible Yocto builds across different development hosts

Before running the build, the KAS environment must be initialized properly.

dvdk@vagrant:~/yocto$ mkdir desk-mx6ul-l
dvdk@vagrant:~/yocto$ cd desk-mx6ul-l/
dvdk@vagrant:~/yocto/desk-mx6ul-l$ virtualenv -p /usr/bin/python3 venv
created virtual environment CPython3.8.10.final.0-64 in 30634ms
  creator CPython3Posix(dest=/home/dvdk/yocto/desk-mx6ul-l/venv, clear=False, global=False)
  seeder FromAppData(download=False, pip=latest, setuptools=latest, wheel=latest, pkg_resources=latest, via=copy, app_data_dir=/home/dvdk/.local/share/virtualenv/seed-app-data/v1.0.1.debian.1)
  activators BashActivator,CShellActivator,FishActivator,PowerShellActivator,PythonActivator,XonshActivator
dvdk@vagrant:~/yocto/desk-mx6ul-l$ source venv/bin/activate
(venv) dvdk@vagrant:~/yocto/desk-mx6ul-l$ pip3 install kas==4.7
Processing /home/dvdk/.cache/pip/wheels/38/a9/8c/311243e3d15e03994982f62fc92845e0840204e8e726a4760b/kas-4.7-py3-none-any.whl
Collecting GitPython<4,>=3.1.0
  Using cached gitpython-3.1.45-py3-none-any.whl (208 kB)
Collecting PyYAML<7,>=3.0
  Using cached PyYAML-6.0.3-cp38-cp38-manylinux2014_x86_64.manylinux_2_17_x86_64.manylinux_2_28_x86_64.whl (806 kB)
Collecting kconfiglib<15,>=14.1.0
  Using cached kconfiglib-14.1.0-py2.py3-none-any.whl (145 kB)
Collecting distro<2,>=1.0.0
  Using cached distro-1.9.0-py3-none-any.whl (20 kB)
Collecting jsonschema<5,>=2.5.0
  Using cached jsonschema-4.23.0-py3-none-any.whl (88 kB)
Collecting typing-extensions>=3.10.0.2; python_version < "3.10"
  Using cached typing_extensions-4.13.2-py3-none-any.whl (45 kB)
Collecting gitdb<5,>=4.0.1
  Using cached gitdb-4.0.12-py3-none-any.whl (62 kB)
Collecting jsonschema-specifications>=2023.03.6
  Using cached jsonschema_specifications-2023.12.1-py3-none-any.whl (18 kB)
Collecting rpds-py>=0.7.1
  Using cached rpds_py-0.20.1-cp38-cp38-manylinux_2_17_x86_64.manylinux2014_x86_64.whl (360 kB)
Collecting pkgutil-resolve-name>=1.3.10; python_version < "3.9"
  Using cached pkgutil_resolve_name-1.3.10-py3-none-any.whl (4.7 kB)
Collecting referencing>=0.28.4
  Using cached referencing-0.35.1-py3-none-any.whl (26 kB)
Collecting importlib-resources>=1.4.0; python_version < "3.9"
  Using cached importlib_resources-6.4.5-py3-none-any.whl (36 kB)
Collecting attrs>=22.2.0
  Using cached attrs-25.3.0-py3-none-any.whl (63 kB)
Collecting smmap<6,>=3.0.1
  Using cached smmap-5.0.2-py3-none-any.whl (24 kB)
Collecting zipp>=3.1.0; python_version < "3.10"
  Using cached zipp-3.20.2-py3-none-any.whl (9.2 kB)
Installing collected packages: typing-extensions, smmap, gitdb, GitPython, PyYAML, kconfiglib, distro, rpds-py, attrs, referencing, zipp, importlib-resources, jsonschema-specifications, pkgutil-resolve-name, jsonschema, kas
Successfully installed GitPython-3.1.45 PyYAML-6.0.3 attrs-25.3.0 distro-1.9.0 gitdb-4.0.12 importlib-resources-6.4.5 jsonschema-4.23.0 jsonschema-specifications-2023.12.1 kas-4.7 kconfiglib-14.1.0 pkgutil-resolve-name-1.3.10 referencing-0.35.1 rpds-py-0.20.1 smmap-5.0.2 typing-extensions-4.13.2 zipp-3.20.2
(venv) dvdk@vagrant:~/yocto/desk-mx6ul-l$ g

then, fetch the meta-desk-mx repositories with the proper branch:

(venv) dvdk@vagrant:~/yocto/desk-mx6ul-l$ git clone git@git.dave.eu:desk-mx-l/meta-desk-mx.git -b desk-mx6ul-l-6.0.0

Running the build

Please note that even the basic root file system requires a few hours to build on a mid/hi range desktop (4-6 cores, 8-12 GiB RAM) also depending on your Internet connection speed (all sources are fetched from the network). Nearly 20GiB of disk space is required for the build. The process may be slowed down significantly since the performances of a virtual machine are reduced if compared to the physical hardware. Thus, it's recommended to check the hardware capabilities of the host system and, when building with Yocto is required, to consider the following options:

• Migrating the build system to a physical machine
• Assuming that the host system has the required resources, extending the hardware capabilities of the default MVM (e.g. adding more cores and disk space).

Once the initialization phase, developers can choose the Yocto image to build with KAS

• for example build of dave-image-minimal image with DESK-MX6UL-L AXEL ULite machine and fsl-imx-fb distro, enter the repo directory and

(venv) dvdk@vagrant:~/yocto/desk-mx6ul-l$ cd meta-desk-mx/
(venv) dvdk@vagrant:~/yocto/desk-mx6ul-l/meta-desk-mx/meta-desk-mx$ kas-container --repo-rw --ssh-dir ~/.ssh build ci/desk-mx6ul-axelulite.yml:ci/fsl-imx-fb.yml:ci/dave-image-minimal.yml

• for example build of dave-image-minimal image with DESK-MX6UL-L SBC RIALTO machine and fsl-imx-fb distro, enter the repo directory and

(venv) dvdk@vagrant:~/yocto/desk-mx6ul-l$ cd meta-desk-mx/
(venv) dvdk@vagrant:~/yocto/desk-mx6ul-l/meta-desk-mx/meta-desk-mx$ kas-container --repo-rw --ssh-dir ~/.ssh build ci/desk-mx6ul-rialto.yml:ci/fsl-imx-fb.yml:ci/dave-image-minimal.yml

• in case of error due to downloads path, please use the command below into the repository directory

export DL_DIR=./downloads

Once the build process is completed, the resulting files (the U-Boot binaries, the Linux kernel image, the device tree blob, the .tar.gz compressed root file system image, etc.) will be available in build/tmp/deploy/images/<machine_name>.

Generating the SDKs

(venv) dvdk@vagrant:~/yocto/desk-mx6ul-l/meta-desk-mx/meta-desk-mx$ KAS_TASK="populate_sdk" kas-container --repo-rw --ssh-dir ~/.ssh build ci/desk-mx6ul-axelulite.yml:ci/fsl-imx-fb.yml:ci/core-image-minimal.yml

Generating the Toolchain

The toolchain can be created by the following command:

(venv) dvdk@vagrant:~/yocto/desk-mx6ul-l/meta-desk-mx/meta-desk-mx$ KAS_TARGET="meta-toolchain" kas-container --repo-rw --ssh-dir ~/.ssh build ci/desk-mx6ul-axelulite.yml:ci/fsl-imx-fb.yml:ci/dave-image-minimal.yml

(venv) dvdk@vagrant:~/yocto/desk-mx6ul-l/meta-desk-mx/meta-desk-mx$ KAS_TARGET="meta-toolchain" kas-container --repo-rw --ssh-dir ~/.ssh build ci/desk-mx6ul-rialto.yml:ci/fsl-imx-fb.yml:ci/dave-image-minimal.yml

Building additional packages

To build additional packages, for example memtester the user need to perform the following command

(venv) dvdk@vagrant:~/yocto/desk-mx6ul-l/meta-desk-mx/meta-desk-mx$ KAS_TARGET="memtester" kas-container --repo-rw --ssh-dir ~/.ssh build ci/desk-mx6ul-axelulite.yml:ci/fsl-imx-fb.yml:ci/dave-image-minimal.yml

(venv) dvdk@vagrant:~/yocto/desk-mx6ul-l/meta-desk-mx/meta-desk-mx$ KAS_TARGET="memtester" kas-container --repo-rw --ssh-dir ~/.ssh build ci/desk-mx6ul-rialto.yml:ci/fsl-imx-fb.yml:ci/dave-image-minimal.yml

Building with bitbake

To use the traditional bitbake instead of kas, it is possible to invoke a kas shell where using it:

(venv) dvdk@vagrant:~/yocto/desk-mx6ul-l/meta-desk-mx$  kas-container --repo-rw --ssh-dir ~/.ssh shell ci/desk-mx6ul-axelulite.yml:ci/fsl-imx-fb.yml:ci/dave-image-minimal.yml
2025-12-18 10:32:55 - INFO     - kas 4.7 started
2025-12-18 10:32:55 - INFO     - Using /repo as root for repository meta-desk-mx
2025-12-18 10:32:55 - INFO     - Repository meta-dave already contains 988f0475300d2f5ff4cea89df5eebfb16e8ad28d as commit
2025-12-18 10:32:55 - INFO     - Repository meta-flutter already contains 545eda504de8d9e7b7d2911898e891cb016b6693 as commit
2025-12-18 10:32:55 - INFO     - Repository poky already contains 200d12b6a58ad961d60a7774ca0f7a9d29498724 as commit
2025-12-18 10:32:55 - INFO     - Repository meta-openembedded already contains 72018ca1b1a471226917e8246e8bbf9a374ccf97 as commit
2025-12-18 10:32:55 - INFO     - Repository meta-clang already contains 2b7433611d80f6d0ee1b04156fa91fc73d3c2665 as commit
2025-12-18 10:32:55 - INFO     - Repository meta-freescale already contains 0627128b341cfb2bef7a0832ce8cac0ce1127f13 as commit
2025-12-18 10:32:55 - INFO     - Repository meta-freescale-3rdparty already contains 6c063450d464eb2f380443c7d9af1b94ce9b9d75 as commit
2025-12-18 10:32:55 - INFO     - Repository meta-freescale-distro already contains b9d6a5d9931922558046d230c1f5f4ef6ee72345 as commit
2025-12-18 10:32:55 - INFO     - Repository meta-arm already contains 950a4afce46a359def2958bd9ae33fc08ff9bb0d as commit
2025-12-18 10:32:55 - INFO     - Repository meta-qt6 already contains 586a6cb5aec755803a3be3cec359baafe89d6432 as commit
2025-12-18 10:32:55 - INFO     - Repository meta-security already contains 459d837338ca230254baa2994f870bf6eb9d0139 as commit
2025-12-18 10:32:55 - INFO     - Repository meta-timesys already contains 4dc3f4bdfde4a86904b6e1a3d58df4696e7a63fa as commit
2025-12-18 10:32:55 - INFO     - Repository meta-virtualization already contains 6f3c1d8f90947408a6587be222fec575a1ca5195 as commit
2025-12-18 10:32:55 - INFO     - Repository meta-imx already contains e83d4402acde050d2b2761995761c81c797b5b03 as commit
2025-12-18 10:32:55 - INFO     - Repository meta-nxp-connectivity already contains f58365ec75a5768ff3e8e8bcd64f237738c93160 as commit
2025-12-18 10:32:55 - INFO     - Repository meta-nxp-demo-experience already contains e8e646e22b1f926aac83bb7ad522efa9cd8ccc45 as commit
2025-12-18 10:32:55 - INFO     - Repository meta-dave checked out to 988f0475300d2f5ff4cea89df5eebfb16e8ad28d
2025-12-18 10:32:55 - INFO     - Repository meta-flutter checked out to 545eda504de8d9e7b7d2911898e891cb016b6693
2025-12-18 10:32:55 - INFO     - Repository poky checked out to 200d12b6a58ad961d60a7774ca0f7a9d29498724
2025-12-18 10:32:55 - INFO     - Repository meta-openembedded checked out to 72018ca1b1a471226917e8246e8bbf9a374ccf97
2025-12-18 10:32:55 - INFO     - Repository meta-clang checked out to 2b7433611d80f6d0ee1b04156fa91fc73d3c2665
2025-12-18 10:32:55 - INFO     - Repository meta-freescale checked out to 0627128b341cfb2bef7a0832ce8cac0ce1127f13
2025-12-18 10:32:55 - INFO     - Repository meta-freescale-3rdparty checked out to 6c063450d464eb2f380443c7d9af1b94ce9b9d75
2025-12-18 10:32:55 - INFO     - Repository meta-freescale-distro checked out to b9d6a5d9931922558046d230c1f5f4ef6ee72345
2025-12-18 10:32:55 - INFO     - Repository meta-arm checked out to 950a4afce46a359def2958bd9ae33fc08ff9bb0d
2025-12-18 10:32:55 - INFO     - Repository meta-qt6 checked out to 586a6cb5aec755803a3be3cec359baafe89d6432
2025-12-18 10:32:55 - INFO     - Repository meta-security checked out to 459d837338ca230254baa2994f870bf6eb9d0139
2025-12-18 10:32:55 - INFO     - Repository meta-timesys checked out to 4dc3f4bdfde4a86904b6e1a3d58df4696e7a63fa
2025-12-18 10:32:55 - INFO     - Repository meta-virtualization checked out to 6f3c1d8f90947408a6587be222fec575a1ca5195
2025-12-18 10:32:56 - INFO     - Repository meta-imx checked out to e83d4402acde050d2b2761995761c81c797b5b03
2025-12-18 10:32:56 - INFO     - Repository meta-nxp-connectivity checked out to f58365ec75a5768ff3e8e8bcd64f237738c93160
2025-12-18 10:32:56 - INFO     - Repository meta-nxp-demo-experience checked out to e8e646e22b1f926aac83bb7ad522efa9cd8ccc45
2025-12-18 10:32:56 - INFO     - To start the default build, run: bitbake -c build dave-image-minimal
builder@47e71e32a40b:/build$ 

and then it is possible to run a typical bitbake command, like:

builder@47e71e32a40b:/build$ export DL_DIR=./downloads
builder@47e71e32a40b:/build$ bitbake memtester
Loading cache: 100% |#########################################################################################################################################################| Time: 0:00:04
Loaded 5988 entries from dependency cache.
Parsing recipes: 100% |#######################################################################################################################################################| Time: 0:00:01
Parsing of 3905 .bb files complete (3901 cached, 4 parsed). 5992 targets, 800 skipped, 3 masked, 0 errors.
NOTE: Resolving any missing task queue dependencies

Build Configuration:
BB_VERSION           = "2.8.0"
BUILD_SYS            = "x86_64-linux"
NATIVELSBSTRING      = "debian-12"
TARGET_SYS           = "arm-poky-linux-gnueabi"
MACHINE              = "desk-mx6ul-axelulite"
DISTRO               = "fsl-imx-fb"
DISTRO_VERSION       = "6.6-scarthgap"
TUNE_FEATURES        = "arm vfp cortexa7 neon thumb callconvention-hard"
TARGET_FPU           = "hard"
...
...

Moreover, with kas checkout it is possible to checking out the configuration and - for example - save the bblayers.conf and local.conf files:

(venv) dvdk@vagrant:~/yocto/desk-mx6ul-l/meta-desk-mx$ kas-container --repo-rw --ssh-dir ~/.ssh checkout ci/desk-mx6ul-axelulite.yml:ci/fsl-imx-fb.yml:ci/dave-image-minimal.yml

How to create a bootable SD card

This article shows how to (re)create the bootable SD card, from the binary images produced by the DESK-MX-L Yocto build, using a standard SD image flasher like balenaEtcher

The process is relatively straightforward: it consists of writing the WIC file of interest generated by Yocto onto the SD card. The following instruction explains how to use balenaEtcher on a Windows host. The procedure is similar when working with a Linux host.

• download the desired binary image to flash (*.wic or *.wic.bz2) from the mirror binary server selecting the proper DESK-MX6UL-L release
  • among the binaries made available in the mirror there are several *.wic.bz2 files for the available releases. In particular, there is the dave-image-minimal-desk-mx6ul-axelulite-fsl-imx-fb.wic.bz2 (for AXEL ULite) or dave-image-minimal-desk-mx6ul-rialto-fsl-imx-fb.wic.bz2 (for SBC RIALTO) files. This image is the one used to program the microSD card delivered along with the evaluation kit.
• connect the microSD card to the PC Host
• open balenaEtcher tool
• once the tool is open:
  • select the binary to flash by clicking on "Flash from file"
  • select the microSD to flash by clicking on "Select target"
  • flash the uSD by clicking o "Flash".

Unpacking

Flashing

Validating

SD card structure

The created SD card has the following structure:

• raw sectors for the bootloader storage: tipically this is a 8MB raw part where storing the bootloader binaries for the bootrom startup
• FAT32 first partition: this will be mapped to the /dev/mmcblk0p1 device in Linux
  • usually this partition contains the Linux kernel binary and the device tree blob
  • the splash screen image is stored in this partition too for a splash image showing during U-Boot startup
• ext4 second partition: this will be mapped to the /dev/mmcblk0p2 device in Linux
  • this partition contains the Linux root file system

Creating the SD card from binary artifacts

Even if the overall binary artifacts have been created by the Yocto build, it is highly discouraged to manually create the SD card starting from them.

The Yocto build take care about the overall binary consistance (like kernel modules and so on) avoiding to mistmatch different version.

Moreover, the SD card is intended to be used during the development process and not for the production phase (where other deployment specifications and details have to be taken into account).

Hello word example

Here below an example on C code displaying the classic Hello World! message on the target serial console.

This example shows how to use the arm cross-compiler using the environment configured for this purpose

Setting the cross-compiler

It is assumed that the development environment has been set up properly as described here.

• start the Linux development VM and login into the system
• open a terminal window and cd into your source code directory

dvdk@vagrant:~$ mkdir myproject
dvdk@vagrant:~$ cd myproject/
dvdk@vagrant:~/myproject$ vi hello.c
dvdk@vagrant:~/myproject$ cat hello.c
#include <stdio.h>

int main(){
	printf("Hello, World!\n");
	return 0;
}

• configure the build environment

dvdk@vagrant:~/myproject$ source ~/desk-mx-l/desk-mx6ul-l-1.0.1_env.sh

• as you can see here below, the $CC environment variable has been properly configured for using the SDK sysroot parameter:

dvdk@vagrant:~/myproject$ echo $CC
arm-poky-linux-gnueabi-gcc -march=armv7ve -mfpu=neon -mfloat-abi=hard -mcpu=cortex-a7 --sysroot=/home/dvdk/desk-mx-l/sdk/desk-mx6ul-l-1.0.1-toolchain/sysroots/cortexa7hf-neon-poky-linux-gnueabi
dvdk@vagrant:~/myproject$ 

• invoke the cross-compiler for compiling your source code example: the object file obtained, is a proper ELF 32-bit for the target microprocessor

dvdk@vagrant:~/myproject$ $CC hello.c -o hello
dvdk@vagrant:~/myproject$ file hello
hello: ELF 32-bit LSB executable, ARM, EABI5 version 1 (SYSV), dynamically linked, interpreter /lib/ld-linux-armhf.so.3, for GNU/Linux 3.2.0, BuildID[sha1]=9afa4b55f9a187d69a3a8356ea2d2afc3565cf7a, not stripped
dvdk@vagrant:~/myproject$ 

Running the example on the target

Now it is enough to copy the object file in the /home/root rfs directory and boot from nfs...

dvdk@vagrant:~/myproject$ sudo cp hello /home/dvdk/desk-mx-l/rfs/desk-mx6ul-l/home/root/
dvdk@vagrant:~/myproject$ sudo ls -la /home/dvdk/desk-mx-l/rfs/desk-mx6ul-l/home/root/
total 32
drwx------ 2 root root  4096 Jun  8 12:36 .
drwxr-xr-x 3 root root  4096 Jan 28 23:54 ..
-rwxr-xr-x 1 root root 16432 Jun  8 12:36 hello
-rw-r--r-- 1 root root  1011 Nov 25  2020 .profile
dvdk@vagrant:~/myproject$ 

on the target:

...
...
...
[  OK  ] Started Getty on tty1.
[  OK  ] Reached target Login Prompts.
[  OK  ] Started Job spooling tools.
         Starting Network Time Service (one-shot ntpdate mode)...
         Starting System Logging Service...
[  OK  ] Reached target Timers.
[  OK  ] Started RPC Bind Service.
[  OK  ] Started Avahi mDNS/DNS-SD Stack.
[  OK  ] Started Telephony service.
[  OK  ] Started NFS status monitor for NFSv2/3 locking..
[  OK  ] Started Network Time Service (one-shot ntpdate mode).

NXP i.MX Release Distro 4.14-sumo desk-mx6ul-axelulite ttymxc0

desk-mx6ul-axelulite login: root
root@desk-mx6ul-axelulite:~# ls -la
total 32
drwx------ 2 root root  4096 Jul  2  2021 .
drwxr-xr-x 3 root root  4096 Jun 16  2021 ..
-rw------- 1 root root    25 Jun 29  2021 .bash_history
-rwxr-xr-x 1 root root 16436 Jul  2  2021 hello
root@desk-mx6ul-axelulite:~# ./hello
Hello, World!
root@desk-mx6ul-axelulite:~#

---

Deployment

Booting from NAND flash

With respect to the NOR flash memories, NAND devices are known to be quite challenging with regard to the reliability. This is especially true when the NAND flash is used as the boot device. Several techniques such as wear leveling and bad block management have to be implemented to achieve an acceptable reliability.

This document provides information about the NAND device management, in order to handle it properly when it is used as the boot device on NXP i.MX6-based products.

Even though the example shown here refers to an i.MX6 UltraLite board, the approach is substantially the same across all the i.MX6 family.

The test bed used in this example consists of an i.MX6 UltraLite board equipped with a 128MB 8-bit asynchronous 1-bit ECC SLC NAND memory which is connected to the EIM bus of the SoC. The boot firmware image is the U-Boot binary files (desk-mx6ul-l-1.0.2_mx6uldesk_axelulite_nand_SPL and desk-mx6ul-l-1.0.2_mx6uldesk_axelulite_nand_u-boot.img). Its size is about 535 kB. From the point of view of MTD partitions, the boot partition for SPL is mtd0 is 2MB while the second stage partition mtd1 is 6MB.

Boot partition organization

The following image shows the organization of the boot partition.

Organization of the boot partition

The bootrom plays a major role in the boot process of any i.MX6 SoC. In case the NAND memory is the boot devices, this implies that the boot partition must be organized in order fulfill the bootrom requirements. Specifically, it contains:

• A 1MB area (named Flash Control Block, FCB) which, in turn, includes
  • A data structure called NAND Control Block (NCB)
  • Three addresses which indicate where are located
    • The Discovered Bad Block Table (DBBT) which is the data structure used to manage the bad blocks of the NAND flash
    • The first copy of the firmware to load
    • The second (redundant) copy of the firmware to load
• The DBBT
• The first copy of the firmware
• The second copy of the firmware.

For more details about the bootrom e the NAND boot process, please refer to the System Boot chapter of the Reference Manual of the specific i.MX6 Application Processor.

The following section will describe how to burn the boot partition in practice.

How to burn the boot partition

The burning of the boot partition is performed by the kobs-ng tool and the standard flash_erase and nandwrite flash utilities.

When the NAND flash is not burned yet, the product is usually configured in order to boot from a different device such as an SD card or through serial download mode. Once the Linux kernel is up and running, the kobs-ng can be run as shown in the following example:

root@desk-mx6ul-axelulite:~# kobs-ng -x -v -w desk-mx6ul-l-1.0.2_mx6uldesk_axelulite_nand_SPL
MTD CONFIG:
  chip_0_device_path = "/dev/mtd0"
  chip_1_device_path = "(null)"
  search_exponent = 2
  data_setup_time = 80
  data_hold_time = 60
  address_setup_time = 25
  data_sample_time = 6
  row_address_size = 3
  column_address_size = 2
  read_command_code1 = 0
  read_command_code2 = 48
  boot_stream_major_version = 1
  boot_stream_minor_version = 0
  boot_stream_sub_version = 0
  ncb_version = 3
  boot_stream_1_address = 0
  boot_stream_2_address = 0
  secondary_boot_stream_off_in_MB = 64
         -- We add the 1k-padding to the uboot.
.tmp_kobs_ng: verifying using key '00000000000000000000000000000000'
.tmp_kobs_ng: is a valid bootstream for key '00000000000000000000000000000000'
mtd: use new bch layout raw access mode
mtd: opening: "/dev/mtd0"
NFC geometry :
        ECC Strength       : 2
        Page Size in Bytes : 2071
        Metadata size      : 10
        ECC Chunk Size in byte : 512
        ECC Chunk count        : 4
        Block Mark Byte Offset : 2028
        Block Mark Bit Offset  : 2
====================================================
mtd: opened '/dev/mtd0' - '(null)'
mtd: max_boot_stream_size_in_bytes = 524288
mtd: boot_stream_size_in_bytes = 57344
mtd: boot_stream_size_in_pages = 28
mtd: #1 0x00100000 - 0x00180000 (0x0010e000)
mtd: #2 0x00180000 - 0x00200000 (0x0018e000)
FCB
  m_u32Checksum = 0x00000000
  m_u32FingerPrint = 0x20424346
  m_u32Version = 0x01000000
  m_NANDTiming.m_u8DataSetup = 80
  m_NANDTiming.m_u8DataHold = 60
  m_NANDTiming.m_u8AddressSetup = 25
  m_NANDTiming.m_u8DSAMPLE_TIME = 6
  m_u32PageDataSize = 2048
  m_u32TotalPageSize = 2112
  m_u32SectorsPerBlock = 64
  m_u32NumberOfNANDs = 0
  m_u32TotalInternalDie = 0
  m_u32CellType = 0
  m_u32EccBlockNEccType = 1
  m_u32EccBlock0Size = 512
  m_u32EccBlockNSize = 512
  m_u32EccBlock0EccType = 1
  m_u32MetadataBytes = 10
  m_u32NumEccBlocksPerPage = 3
  m_u32EccBlockNEccLevelSDK = 0
  m_u32EccBlock0SizeSDK = 0
  m_u32EccBlockNSizeSDK = 0
  m_u32EccBlock0EccLevelSDK = 0
  m_u32NumEccBlocksPerPageSDK = 0
  m_u32MetadataBytesSDK = 0
  m_u32EraseThreshold = 0
  m_u32Firmware1_startingPage = 512
  m_u32Firmware2_startingPage = 768
  m_u32PagesInFirmware1 = 28
  m_u32PagesInFirmware2 = 28
  m_u32DBBTSearchAreaStartAddress = 256
  m_u32BadBlockMarkerByte = 2028
  m_u32BadBlockMarkerStartBit = 2
  m_u32BBMarkerPhysicalOffset = 2048
  m_u32BCHType = 0
  m_NANDTMTiming.m_u32TMTiming2_ReadLatency = 0
  m_NANDTMTiming.m_u32TMTiming2_PreambleDelay = 0
  m_NANDTMTiming.m_u32TMTiming2_CEDelay = 0
  m_NANDTMTiming.m_u32TMTiming2_PostambleDelay = 0
  m_NANDTMTiming.m_u32TMTiming2_CmdAddPause = 0
  m_NANDTMTiming.m_u32TMTiming2_DataPause = 0
  m_NANDTMTiming.m_u32TMSpeed = 0
  m_NANDTMTiming.m_u32TMTiming1_BusyTimeout = 0
  m_u32DISBBM = 0
  m_u32BBMarkerPhysicalOffsetInSpareData = 0
  m_u32OnfiSyncEnable = 0
  m_NANDONFITiming.m_u32ONFISpeed = 0
  m_NANDONFITiming.m_u32ONFITiming_ReadLatency = 0
  m_NANDONFITiming.m_u32ONFITiming_CEDelay = 0
  m_NANDONFITiming.m_u32ONFITiming_PreambleDelay = 0
  m_NANDONFITiming.m_u32ONFITiming_PostambleDelay = 0
  m_NANDONFITiming.m_u32ONFITiming_CmdAddPause = 0
  m_NANDONFITiming.m_u32ONFITiming_DataPause = 0
  m_NANDONFITiming.m_u32ONFITiming_BusyTimeout = 0
  m_u32DISBBSearch = 0
  m_u32RandomizerEnable = 0
  m_u32ReadRetryEnable = 0
  m_u32ReadRetrySeqLength = 0
DBBT
  m_u32Checksum = 0x00000000
  m_u32FingerPrint = 0x54424244
  m_u32Version = 0x01000000
  m_u32DBBTNumOfPages = 0
Firmware: image #0 @ 0x100000 size 0xe000 - available 0x80000
Firmware: image #1 @ 0x180000 size 0xe000 - available 0x80000
-------------- Start to write the [ FCB ] -----
mtd: erasing @0:0x0-0x20000
mtd: Writing FCB0 [ @0:0x0 ] (840) *
mtd: erasing @0:0x20000-0x40000
mtd: Writing FCB1 [ @0:0x20000 ] (840) *
mtd: erasing @0:0x40000-0x60000
mtd: Writing FCB2 [ @0:0x40000 ] (840) *
mtd: erasing @0:0x60000-0x80000
mtd: Writing FCB3 [ @0:0x60000 ] (840) *
mtd_commit_bcb(FCB): status 0

-------------- Start to write the [ DBBT ] -----
mtd: erasing @0:0x80000-0xa0000
mtd: Writing DBBT0 [ @0:0x80000 ] (800) *
mtd: erasing @0:0xa0000-0xc0000
mtd: Writing DBBT1 [ @0:0xa0000 ] (800) *
mtd: erasing @0:0xc0000-0xe0000
mtd: Writing DBBT2 [ @0:0xc0000 ] (800) *
mtd: erasing @0:0xe0000-0x100000
mtd: Writing DBBT3 [ @0:0xe0000 ] (800) *
mtd_commit_bcb(DBBT): status 0

---------- Start to write the [ .tmp_kobs_ng ]----
mtd: Writting .tmp_kobs_ng: #0 @0: 0x00100000 - 0x0010e000
mtd: erasing @0:0x100000-0x120000
mtd: We write one page for save guard. *
mtd: Writting .tmp_kobs_ng: #1 @0: 0x00180000 - 0x0018e000
mtd: erasing @0:0x180000-0x1a0000
mtd: We write one page for save guard. *
root@desk-mx6ul-axelulite:~#

then the second mtd1 partition can be written using nandwrite:

root@desk-mx6ul-axelulite:~# flash_erase /dev/mtd1 0 0
Erasing 128 Kibyte @ 5e0000 -- 100 % complete
root@desk-mx6ul-axelulite:~# nandwrite -p /dev/mtd1 desk-mx6ul-l-1.0.2_mx6uldesk_axelulite_nand_u-boot.img
Writing data to block 0 at offset 0x0
Writing data to block 1 at offset 0x20000
Writing data to block 2 at offset 0x40000
Writing data to block 3 at offset 0x60000
Writing data to block 4 at offset 0x80000
root@desk-mx6ul-axelulite:~#

In this case, the SPL boot partition–/dev/mtd0, indicated as a parameter of the command line–is 2MB. The u-boot.img partition–/dev/mtd1 is used for the second stage binary image.

---

Customizing the splash screen

Resources

For further details on splash screen support in U-Boot, please refer to:

• U-Boot Splash Screen Support
• U-Boot Bitmap Support

Instructions

The following U-Boot environment variables are required:

• splashimage: RAM address where the BMP image is loaded. Please note that it must be a 32-bit aligned address with a 0x2 offset (eg: 0x20000002)
• loadsplash: comand for loading the BMP image from the storage device (e.g flash memory) to RAM. This command is automatically run by U-Boot at startup

Please note that loadsplash command will differ depends on used storage device.

Splash image in NOR SPI flash

U-Boot variables

loadsplash=run spi_loadsplash
spi_loadsplash=sf probe; sf read ${splashimage} 0xa00000 ${splashsize}
splashfile=splash_image.bmp
splashimage=0x80800000
splashsize=0x120000
loadsplashfile=tftpboot ${loadaddr} desk-mxul-l/${splashfile}
spi_updatesplash=sf probe; sf erase 0xa00000 +${filesize}; sf write ${loadaddr} 0xa00000 ${filesize}

Commands

The following commands are used to store in NOR SPI flash a BMP image loaded via tftp:

run loadsplashfile
run spi_updatesplash

Splash image in NAND flash

U-Boot variables

mtdparts=mtdparts=gpmi-nand:2M(nand-SPL),6M(nand-uboot),1M(nand-env1),1M(nand-env2),1M(nand-fdt),1M(nand-spare),8M(nand-kernel),4M(nand-splash),-(nand-ubi)
loadsplash=run nand_loadsplash
nand_loadsplash=nand read ${splashimage} nand-splash ${splashsize}
splashfile=splash_image.bmp
splashimage=0x80800000
splashsize=0x120000
loadsplashfile=tftpboot ${loadaddr} desk-mxul-l/${splashfile}
nand_updatesplash=nand erase.part nand-splash; nand write ${loadaddr} nand-splash ${filesize}

Please note that the NAND mtd partition for the splash image (nand-splash) is defined using the mtdparts parameter, and then referenced by the nand {erase,read,write} commands.

Commands

The following commands are used to store in NAND flash a BMP image loaded via tftp:

run loadsplashfile
run nand_updatesplash

---

Standalone boot

Introduction

This document was written and tested with the software/hardware combination described in the history table above. However, it contains general concepts that can be adapted on any DAVE Embedded Systems' Linux platform.

The following programming examples are intended for laboratory usage or for preliminary deployment strategy. A complete deployment strategy has to be carefully identifiyed taking into account the overall arguments like: boot speed, safe boot, recovery mechanisms, watchdog supervisor, etc.

We'll explain how to program and configure a <SOM> to boot in standalone mode, without the need of a system microSD card or an NFS server, with two options:

• booting with NOR and NAND internal storage
  • in this configuration the primary boot images will be fetched from NOR flash storage, while the root file system will be fetched from NAND flash

Program boot images into NOR flash

U-Boot

Update to the latest U-Boot version allows usage of u-boot environment variables available.

=> run load_spl
Using ethernet@2188000 device
TFTP from server 192.168.0.125; our IP address is 192.168.0.90
Filename 'desk-mx6ul-l/SPL'.
Load address: 0x80800000
Loading: #############
         248 KiB/s
done
Bytes transferred = 64512 (fc00 hex)
=> run spi_update
  spi_update_spl spi_update_uboot spi_updatefdt spi_updatek spi_updatesplash
=> run spi_update_spl
SF: Detected is25lp128 with page size 256 Bytes, erase size 64 KiB, total 16 MiB
SF: 65536 bytes @ 0x0 Erased: OK
device 0 offset 0x400, size 0xfc00
SF: 64512 bytes @ 0x400 Written: OK
=> run load_uboot
Using ethernet@2188000 device
TFTP from server 192.168.0.125; our IP address is 192.168.0.90
Filename 'desk-mx6ul-l/u-boot.img'.
Load address: 0x80800000
Loading: #################################################################
         #################################################################
         ##########################
         268.6 KiB/s
done
Bytes transferred = 794660 (c2024 hex)
=> run spi_update_uboot
SF: Detected is25lp128 with page size 256 Bytes, erase size 64 KiB, total 16 MiB
SF: 851968 bytes @ 0x10000 Erased: OK
device 0 offset 0x10000, size 0xc2024
SF: 794660 bytes @ 0x10000 Written: OK
=>

kernel image and device tree

We assume that the environment variables in U-Boot are properly configured:

env default spi_loadk
env default spi_loadfdt
env default spi_updatek
env default spi_updatefdt
env default spi_nand
saveenv

• Update the bootfile and fdtfile environment variables to fit the filename as found inside the TFTP server.
• Program kernel and device tree on NOR flash with the following U-Boot command

sf probe; run loadk spi_updatek loadfdt spi_updatefdt

E.g.:

=> run loadk spi_updatek loadfdt spi_updatefdt
Using ethernet@2188000 device
TFTP from server 192.168.0.125; our IP address is 192.168.0.90
Filename 'desk-mx6ul-l/uImage'.
Load address: 0x80800000
Loading: #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################
         267.6 KiB/s
done
Bytes transferred = 10401080 (9eb538 hex)
SF: 11534336 bytes @ 0x200000 Erased: OK
device 0 offset 0x200000, size 0x9eb538
SF: 10401080 bytes @ 0x200000 Written: OK
Using ethernet@2188000 device
TFTP from server 192.168.0.125; our IP address is 192.168.0.90
Filename 'desk-mx6ul-l/imx6ul-axelulite-cb003a.dtb'.
Load address: 0x83000000
Loading: #######
         209 KiB/s
done
Bytes transferred = 32964 (80c4 hex)
SF: 524288 bytes @ 0x180000 Erased: OK
device 0 offset 0x180000, size 0x80c4
SF: 32964 bytes @ 0x180000 Written: OK
=>

then save the new boot configuration from SPI:

=> setenv bootcmd run spi_nand
=> saveenv

Program root file system into NAND flash

• boot the system via SD or NFS as described in the Booting from NFS
• by default, the NAND is already partitioned to allow booting from NAND-only (see next section) and, thus, some partitions are reserved for u-boot and kernel images. Here we won't modify this default configuration. The MTD partitions can be dumped with /proc/mtd (the partition's name should be self-explanatory)

root@desk-mx6ul-axelulite:~# cat /proc/mtd
dev:    size   erasesize  name
mtd0: 00200000 00080000 "nand-SPL"
mtd1: 00600000 00080000 "nand-uboot"
mtd2: 00100000 00080000 "nand-env1"
mtd3: 00100000 00080000 "nand-env2"
mtd4: 00100000 00080000 "nand-fdt"
mtd5: 00100000 00080000 "nand-spare"
mtd6: 00c00000 00080000 "nand-kernel"
mtd7: 00400000 00080000 "nand-splash"
mtd8: 7e400000 00080000 "nand-ubi"
mtd9: 00010000 00010000 "spi-SPL"
mtd10: 000f0000 00010000 "spi-uboot"
mtd11: 00040000 00010000 "spi-env1"
mtd12: 00040000 00010000 "spi-env2"
mtd13: 00080000 00010000 "spi-dtb"
mtd14: 00b00000 00010000 "spi-kernel"
mtd15: 00200000 00010000 "spi-splash"
mtd16: 00100000 00010000 "spi-free"
root@desk-mx6ul-axelulite:~#

Please note that MTD partition index may change depending of flash device availability, flash device size, u-boot environment variables or kernel device driver load order. Always take care of looking inside /proc/mtd to match your specific layout

• Format and initialize nand-ubi partition, which in our case is mtd8, using UBI with:

ubiformat /dev/mtd8
ubiattach -m 8
ubimkvol /dev/ubi0 -N rootfs -m

E.g.

root@desk-mx6ul-axelulite:~# ubiformat /dev/mtd8
ubiformat: mtd8 (nand), size 109051904 bytes (104.0 MiB), 832 eraseblocks of 131072 bytes (128.0 KiB), min. I/O size 2048 bytes
libscan: scanning eraseblock 831 -- 100 % complete  
ubiformat: 832 eraseblocks have valid erase counter, mean value is 39
ubiformat: formatting eraseblock 831 -- 100 % complete  
root@desk-mx6ul-axelulite:~# ubiattach -m 8
UBI device number 0, total 832 LEBs (105644032 bytes, 100.7 MiB), available 808 LEBs (102596608 bytes, 97.8 MiB), LEB size 126976 bytes (124.0 KiB)
root@desk-mx6ul-axelulite:~# ubimkvol /dev/ubi0 -N rootfs -m
Set volume size to 102596608
Volume ID 0, size 808 LEBs (102596608 bytes, 97.8 MiB), LEB size 126976 bytes (124.0 KiB), dynamic, name "rootfs", alignment 1

• Now mount the UBI volume using UBIFS in a temporary directory

mkdir -p /mnt/nand
mount -t ubifs ubi0_0 /mnt/nand

E.g.:

root@desk-mx6ul-axelulite:~# mkdir -p /mnt/nand
root@desk-mx6ul-axelulite:~# mount -t ubifs ubi0_0 /mnt/nand/
root@desk-mx6ul-axelulite:~# dmesg | tail -n 7
[   86.268589] UBIFS (ubi0:0): Mounting in unauthenticated mode
[   86.272276] UBIFS (ubi0:0): background thread "ubifs_bgt0_0" started, PID 276
[   86.302293] UBIFS (ubi0:0): UBIFS: mounted UBI device 0, volume 0, name "rootfs"
[   86.302349] UBIFS (ubi0:0): LEB size: 126976 bytes (124 KiB), min./max. I/O unit sizes: 2048 bytes/2048 bytes
[   86.302377] UBIFS (ubi0:0): FS size: 101199872 bytes (96 MiB, 797 LEBs), max 808 LEBs, journal size 5079040 bytes (4 MiB, 40 LEBs)
[   86.302411] UBIFS (ubi0:0): reserved for root: 4779919 bytes (4667 KiB)
[   86.302431] UBIFS (ubi0:0): media format: w5/r0 (latest is w5/r0), UUID 36C676F6-9160-4334-B687-9CEE57A30FEF, small LPT model

• you can now extract the root file system into that directory

tar xvjf dave-image-minimal-desk-mx6ul-axelulite-fsl-imx-fb.tar.bz2 -C /mnt/nand/

• finally, you need to cleanly umount and detach the MTD partition

umount /mnt/nand/
ubidetach -m 8

E.g.

root@desk-mx6ul-axelulite:~# umount /mnt/nand/
root@desk-mx6ul-axelulite:~# ubidetach -m 8
root@desk-mx6ul-axelulite:~# dmesg | tail -n 4
[  105.493236] UBIFS (ubi0:0): un-mount UBI device 0
[  105.493401] UBIFS (ubi0:0): background thread "ubifs_bgt0_0" stops
[  109.963440] ubi0: detaching mtd8
[  109.971275] ubi0: mtd8 is detached

You can now safely reboot or turn off the system.

In U-Boot environment check the following variable, which must contain the same MTD partition number used above

nandargs=setenv bootargs ubi.mtd=8 root=ubi0_0 rootfstype=ubifs rw

---

Peripherals

Peripheral Audio

The audio peripheral is not available - as default option - on AXEL ULite EVK. Please contact Sales department for this option.

Device tree configuration

AXEL ULite SOM

Here below is an example of device tree configuration for the AXEL ULite SOM (using a special version of AXEL ULite EVK mounting option):

From imx6ul-axelulite-cb006c.dts:

        sound {
                compatible = "fsl,imx-audio-tlv320aic31xx";
                model = "axelulite-audio-tlv320aic3100";
                cpu-dai = <&sai2>;
                audio-codec = <&codec>;
                audio-routing =
                        "Speaker", "SPK",
                        "Headphone Jack", "HPL",
                        "Headphone Jack", "HPR",
                        "MIC1LP", "Line In",
                        "MIC1LM", "Line In",
                        "MIC1RP", "Mic Jack",
                        "Mic Jack", "MICBIAS";
                status = "okay";
        };

&i2c4 {
        clock-frequency = <100000>;
        pinctrl-names = "default", "recovery";
        pinctrl-0 = <&pinctrl_i2c4>;
        pinctrl-1 = <&pinctrl_i2c4_recovery>;
        recovery-gpios = <&gpio1 20 0>, <&gpio1 21 0>;
        status = "okay";

        codec: tlv320aic31xx@18 {
                compatible = "ti,tlv320aic3100";
                reg = <0x18>;
                clocks = <&clks IMX6UL_CLK_SAI2>,
                       <&clks IMX6UL_CLK_DUMMY>;
                clock-names = "mclk1", "mclk2";

		gpio-reset = <&gpio1 27 1>;
		HPVDD-supply = <&reg_3p3v>;
		SPRVDD-supply = <&reg_3p3v>;
		SPLVDD-supply = <&reg_3p3v>;
		AVDD-supply = <&reg_3p3v>;
		IOVDD-supply = <&reg_3p3v>;
		DVDD-supply = <&reg_1p8v>;
        };
...
...
&iomuxc {
        pinctrl-0 = <&pinctrl_hog_gpios>;
        imx6ul-axelulite {

        tlv320aic3x {
                pinctrl_tlv320aic3x_1: tlv320aic3x_codecgrp-1{
                        fsl,pins = <
                                MX6UL_PAD_JTAG_TDI__SAI2_TX_BCLK        0x17088
                                MX6UL_PAD_JTAG_TDO__SAI2_TX_SYNC        0x17088
                                MX6UL_PAD_JTAG_TRST_B__SAI2_TX_DATA     0x11088
                                MX6UL_PAD_JTAG_TCK__SAI2_RX_DATA        0x11088
                                MX6UL_PAD_JTAG_TMS__SAI2_MCLK           0x17088
                                MX6UL_PAD_UART3_RTS_B__GPIO1_IO27       0x130b0 /* codec reset */
                        >;
                };
        };

};

Accessing the peripheral AXEL ULite SOM

Access to the audio interface is provided by ALSA (Advanced Linux Sound Architecture), which consists in a kernel driver and a users space library for application developers. A set of standard tools alsa-utils can be used for simple management of the audio codec.

Linux messages at boot time

...
...
[    3.314515] imx-tlv320aic31xx sound: tlv320aic31xx-hifi <-> 202c000.sai mapping ok
...
...
[    3.545396] ALSA device list:
[    3.548401]   #0: axelulite-audio-tlv320aic3100

To list the audio sound cards just use the aplay utility:

root@desk-mx6ul-axelulite:~# aplay -l
**** List of PLAYBACK Hardware Devices ****
card 0: axeluliteaudiot [axelulite-audio-tlv320aic3100], device 0: HiFi tlv320aic31xx-hifi-0 []
  Subdevices: 1/1
  Subdevice #0: subdevice #0
root@desk-mx6ul-axelulite:~#

Usage alsa-utils

root@desk-mx6ul-axelulite:~# aplay audio8k16S.wav 
Playing WAVE 'audio8k16S.wav' : Signed 16 bit Little Endian, Rate 8000 Hz, Stereo

---

Peripheral CAN

The CAN peripheral is not available on AXEL ULite EVK. This peripheral is available on the i.MX6UL standard product RIALTO SBC

Device tree configuration

RIALTO SBC

Here below is an example of device tree configuration used on standard DAVE's kit for the RIALTO SBC:

From imx6ul-lynx-som0022-cb0090.dts:

&can1 {
	pinctrl-names = "default";
	pinctrl-0 = <&pinctrl_flexcan1>;
	status = "okay";
};

From imx6ul-lynx-som0022.dtsi:

...
&iomuxc {
	pinctrl-names = "default";
	pinctrl-0 = <&pinctrl_hog_gpios>;

	imx6ul-lynx {
...
...
		pinctrl_flexcan1: flexcan1grp{
			fsl,pins = <
				MX6UL_PAD_LCD_DATA09__FLEXCAN1_RX	0x1b020
				MX6UL_PAD_LCD_DATA08__FLEXCAN1_TX	0x1b020
			>;
		};
...

Accessing the peripheral RIALTO SBC

Linux messages at boot time

...
...
[    3.047454] can: controller area network core
[    3.057221] can: raw protocol
[    3.069417] can: broadcast manager protocol
[    3.073846] can: netlink gateway - max_hops=1
...
...

Enable the interface and check status

root@desk-mx6ul-rialto:~# ip link set can0 type can bitrate 500000
root@desk-mx6ul-rialto:~# ifconfig can0 up
root@desk-mx6ul-rialto:~# ifconfig can0
can0: flags=193<UP,RUNNING,NOARP>  mtu 16
        unspec 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00  txqueuelen 10  (UNSPEC)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 0  bytes 0 (0.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
        device interrupt 31

root@desk-mx6ul-rialto:~#

Usage with can-utils

This is a usage example with a CAN device which receives a CAN message and sends back two answers (for testing purposes):

• the same message
• the ones' complement message (i.e. each bit is the opposite of the received one)

root@desk-mx6ul-rialto:~# ip link set can0 type can bitrate 500000
root@desk-mx6ul-rialto:~# ifconfig can0 up
root@desk-mx6ul-rialto:~# candump can0 &
[1] 284
interface = can0, family = 29, type = 3, proto = 1
root@desk-mx6ul-rialto:~# cansend can0 -i 0x7ff 00 01 02 03 04 05 06 07
interface = can0, family = 29, type = 3, proto = 1
<0x7ff> [8] 00 01 02 03 04 05 06 07
<0x000> [8] ff fe fd fc fb fa f9 f8
root@desk-mx6ul-rialto:~#

Additional information

Each CAN port appears like a networking interface in the form canX where X is the port number.

Information about programming the CAN socket interface is given in the kernel tree under Documentation/networking/can.rst

Peripheral Ethernet

The ethernet interface is made available through the i.MX6UL fec interface which should be initialized on the device tree.

Device tree configuration

Axel ULite SOM

Here below is an example of device tree configuration used on standard DAVE's kit for the AXEL ULite SOM:

From imx6ul-axelulite.dtsi:

&fec1 {
        pinctrl-names = "default";
        pinctrl-0 = <&pinctrl_enet1>;
        phy-mode = "rmii";
        phy-handle = <&ethphy0>;
        status = "okay";

        mdio {
                #address-cells = <1>;
                #size-cells = <0>;

                ethphy0: ethernet-phy@3 {
                        compatible = "ethernet-phy-ieee802.3-c22";
                        reg = <3>;
			micrel,led-mode = <1>;
			clocks = <&clks IMX6UL_CLK_ENET_REF>;
			clock-names = "rmii-ref";
                };
        };
};
...
...
&iomuxc {
...
...
                pinctrl_enet1: enet1grp {
                        fsl,pins = <
                                MX6UL_PAD_ENET1_RX_EN__ENET1_RX_EN      0x1b0b0
                                MX6UL_PAD_ENET1_RX_ER__ENET1_RX_ER      0x1b0b0
                                MX6UL_PAD_ENET1_RX_DATA0__ENET1_RDATA00 0x1b0b0
                                MX6UL_PAD_ENET1_RX_DATA1__ENET1_RDATA01 0x1b0b0
                                MX6UL_PAD_ENET1_TX_EN__ENET1_TX_EN      0x1b0b0
                                MX6UL_PAD_ENET1_TX_DATA0__ENET1_TDATA00 0x1b0b0
                                MX6UL_PAD_ENET1_TX_DATA1__ENET1_TDATA01 0x1b0b0
                                MX6UL_PAD_ENET1_TX_CLK__ENET1_REF_CLK1  0x4001b0a8
                                MX6UL_PAD_GPIO1_IO07__ENET1_MDC         0x1b0b0
                                MX6UL_PAD_GPIO1_IO06__ENET1_MDIO        0x1b0b0
                                MX6UL_PAD_SNVS_TAMPER1__GPIO5_IO01      0x1b0b0         /* ETH_PHY_RST */
                                MX6UL_PAD_SNVS_TAMPER2__GPIO5_IO02      0x1b0b0         /* ETH_INT */
                        >;
                };

...
...
};

RIALTO SBC

Here below is an example of device tree configuration used on standard DAVE's kit for the RIALTO SBC:

From imx6ul-lynx-som0022.dtsi:

...
...
&fec1 {
	pinctrl-names = "default";
	pinctrl-0 = <&pinctrl_enet1>;
	phy-mode = "rmii";
	phy-handle = <&ethphy0>;
	phy-reset-gpios = <&gpio5 1 GPIO_ACTIVE_HIGH>;
	phy-reset-post-delay = <50>;
	status = "okay";
	fsl,dev_id = <0>;

	mdio: mdio {
		#address-cells = <1>;
		#size-cells = <0>;

		ethphy0: ethernet-phy@3 {
			compatible = "ethernet-phy-ieee802.3-c22";
			reg = <0x03>;
			micrel,led-mode = <1>;
			clocks = <&clks IMX6UL_CLK_ENET_REF>;
			clock-names = "rmii-ref";
		};
	};
};
...
...
&iomuxc {
...
...
		pinctrl_enet1: enet1grp-1 {
			fsl,pins = <
				MX6UL_PAD_ENET1_RX_EN__ENET1_RX_EN	0x1b0b0
				MX6UL_PAD_ENET1_RX_ER__ENET1_RX_ER	0x1b0b0
				MX6UL_PAD_ENET1_RX_DATA0__ENET1_RDATA00	0x1b0b0
				MX6UL_PAD_ENET1_RX_DATA1__ENET1_RDATA01	0x1b0b0
				MX6UL_PAD_ENET1_TX_EN__ENET1_TX_EN	0x1b0b0
				MX6UL_PAD_ENET1_TX_DATA0__ENET1_TDATA00	0x1b0b0
				MX6UL_PAD_ENET1_TX_DATA1__ENET1_TDATA01	0x1b0b0
				MX6UL_PAD_ENET1_TX_CLK__ENET1_REF_CLK1	0x4001b031
				MX6UL_PAD_GPIO1_IO07__ENET1_MDC		0x1b0b0
				MX6UL_PAD_GPIO1_IO06__ENET1_MDIO	0x1b0b0
			>;
		};
...
...
		pinctrl_enet2: enet2grp {
			fsl,pins = <
				MX6UL_PAD_ENET2_RX_EN__ENET2_RX_EN	0x1b0b0
				MX6UL_PAD_ENET2_RX_ER__ENET2_RX_ER	0x1b0b0
				MX6UL_PAD_ENET2_RX_DATA0__ENET2_RDATA00	0x1b0b0
				MX6UL_PAD_ENET2_RX_DATA1__ENET2_RDATA01	0x1b0b0
				MX6UL_PAD_ENET2_TX_EN__ENET2_TX_EN	0x1b0b0
				MX6UL_PAD_ENET2_TX_DATA0__ENET2_TDATA00	0x1b0b0
				MX6UL_PAD_ENET2_TX_DATA1__ENET2_TDATA01	0x1b0b0
				MX6UL_PAD_ENET2_TX_CLK__ENET2_REF_CLK2	0x4001b031
			>;
		};
...
...
}
...
...

From imx6ul-lynx-som0022-cb0090.dts:

...
...
&fec2 {
        pinctrl-names = "default";
        pinctrl-0 = <&pinctrl_enet2>;
        phy-mode = "rmii";
        phy-handle = <&ethphy1>;
        status = "okay";
};

&mdio {
        ethphy1: ethernet-phy@0 {
                compatible = "ethernet-phy-ieee802.3-c22";
                reg = <0>;
                micrel,led-mode = <1>;
                clocks = <&clks IMX6UL_CLK_ENET2_REF>;
                clock-names = "rmii-ref";
        };
};
...
...

Accessing the peripheral in Axel ULite SOM

AXEL ULite SOM provides the primary network interface mapped at eth0.

Linux messages at boot time

...
...
[    1.771162] fec 2188000.ethernet eth0: registered PHC device 0
[   23.370105] fec 2188000.ethernet eth0: Link is Up - 100Mbps/Full - flow control rx/tx
...
...
[   20.262485] Micrel KSZ8081 or KSZ8091 2188000.ethernet-1:03: attached PHY driver (mii_bus:phy_addr=2188000.ethernet-1:03, irq=POLL)
...
...

Cable connection:

...
...
[   93.046409] fec 2188000.ethernet eth0: Link is Up - 100Mbps/Full - flow control rx/tx
...
...

Check the interface with ifconfig

root@desk-mx6ul-axelulite:~# ifconfig eth0
eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 192.168.4.159  netmask 255.255.255.0  broadcast 192.168.4.255
        inet6 fe80::bc0a:b6ff:fe9b:b0f8  prefixlen 64  scopeid 0x20<link>
        ether be:0a:b6:9b:b0:f8  txqueuelen 1000  (Ethernet)
        RX packets 331  bytes 36636 (35.7 KiB)
        RX errors 0  dropped 47  overruns 0  frame 0
        TX packets 77  bytes 11278 (11.0 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

Test with iperf

root@desk-mx6ul-axelulite:~# iperf3 -t 5 -c 192.168.4.47
Connecting to host 192.168.4.47, port 5201
[  5] local 192.168.4.159 port 56244 connected to 192.168.4.47 port 5201
[ ID] Interval           Transfer     Bitrate         Retr  Cwnd
[  5]   0.00-1.00   sec  11.3 MBytes  94.7 Mbits/sec    0    143 KBytes       
[  5]   1.00-2.00   sec  10.8 MBytes  90.4 Mbits/sec    0    143 KBytes       
[  5]   2.00-3.00   sec  10.8 MBytes  90.1 Mbits/sec    0    150 KBytes       
[  5]   3.00-4.00   sec  10.9 MBytes  91.2 Mbits/sec    0    150 KBytes       
[  5]   4.00-5.00   sec  10.8 MBytes  90.3 Mbits/sec    0    157 KBytes       
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bitrate         Retr
[  5]   0.00-5.00   sec  54.4 MBytes  91.3 Mbits/sec    0             sender
[  5]   0.00-5.05   sec  54.1 MBytes  89.9 Mbits/sec                  receiver

iperf Done.

Accessing the peripheral in RIALTO SBC

RIALTO SBC provides the primary network interface mapped at eth0.

Linux messages at boot time

...
...
[    2.501689] fec 2188000.ethernet eth0: registered PHC device 0
[    3.215129] fec 20b4000.ethernet eth1: registered PHC device 1
...
...
[   22.091756] Micrel KSZ8081 or KSZ8091 2188000.ethernet-1:00: attached PHY driver (mii_bus:phy_addr=2188000.ethernet-1:00, irq=POLL)
[   22.201649] Micrel KSZ8081 or KSZ8091 2188000.ethernet-1:03: attached PHY driver (mii_bus:phy_addr=2188000.ethernet-1:03, irq=POLL)
...
...
[   25.209227] fec 20b4000.ethernet eth1: Link is Up - 100Mbps/Full - flow control rx/tx
[   25.289308] fec 2188000.ethernet eth0: Link is Up - 100Mbps/Full - flow control rx/tx
...
...

Check the interface with ifconfig

root@desk-mx6ul-rialto:~# ifconfig
eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 192.168.0.89  netmask 255.255.255.0  broadcast 192.168.0.255
        inet6 fe80::72b3:d5ff:fe3e:ad88  prefixlen 64  scopeid 0x20<link>
        ether 70:b3:d5:3e:ad:88  txqueuelen 1000  (Ethernet)
        RX packets 46  bytes 4780 (4.6 KiB)
        RX errors 0  dropped 1  overruns 0  frame 0
        TX packets 24  bytes 3909 (3.8 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

eth1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 192.168.11.89  netmask 255.255.255.0  broadcast 192.168.11.255
        inet6 fe80::72b3:d5ff:fe3e:ad89  prefixlen 64  scopeid 0x20<link>
        ether 70:b3:d5:3e:ad:89  txqueuelen 1000  (Ethernet)
        RX packets 49  bytes 5633 (5.5 KiB)
        RX errors 0  dropped 1  overruns 0  frame 0
        TX packets 25  bytes 4007 (3.9 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
...
...

root@desk-mx6ul-rialto:~#

Test with iperf

root@desk-mx6ul-rialto:~# iperf3 -t 5 -c 192.168.0.99
Connecting to host 192.168.0.99, port 5201
[  5] local 192.168.0.89 port 39480 connected to 192.168.0.99 port 5201
[ ID] Interval           Transfer     Bitrate         Retr  Cwnd
[  5]   0.00-1.00   sec  11.2 MBytes  94.0 Mbits/sec    0    147 KBytes
[  5]   1.00-2.00   sec  10.9 MBytes  91.1 Mbits/sec    0    147 KBytes
[  5]   2.00-3.00   sec  10.7 MBytes  89.8 Mbits/sec    0    147 KBytes
[  5]   3.00-4.00   sec  10.8 MBytes  90.7 Mbits/sec    0    156 KBytes
[  5]   4.00-5.00   sec  10.8 MBytes  90.2 Mbits/sec    0    156 KBytes
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bitrate         Retr
[  5]   0.00-5.00   sec  54.4 MBytes  91.2 Mbits/sec    0             sender
[  5]   0.00-5.04   sec  54.0 MBytes  89.9 Mbits/sec                  receiver

iperf Done.
root@desk-mx6ul-rialto:~# iperf3 -t 5 -c 192.168.11.99
Connecting to host 192.168.11.99, port 5201
[  5] local 192.168.11.89 port 40244 connected to 192.168.11.99 port 5201
[ ID] Interval           Transfer     Bitrate         Retr  Cwnd
[  5]   0.00-1.00   sec  11.3 MBytes  94.7 Mbits/sec    0    143 KBytes
[  5]   1.00-2.00   sec  10.8 MBytes  90.7 Mbits/sec    0    143 KBytes
[  5]   2.00-3.00   sec  10.8 MBytes  90.6 Mbits/sec    0    157 KBytes
[  5]   3.00-4.00   sec  10.6 MBytes  89.1 Mbits/sec    0    158 KBytes
[  5]   4.00-5.00   sec  10.8 MBytes  91.0 Mbits/sec    0    158 KBytes
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bitrate         Retr
[  5]   0.00-5.00   sec  54.4 MBytes  91.2 Mbits/sec    0             sender
[  5]   0.00-5.04   sec  54.1 MBytes  90.0 Mbits/sec                  receiver

iperf Done.
root@desk-mx6ul-rialto:~#

Peripheral SD

Device tree configuration

Axel ULite SOM

Here below is an example of device tree configuration used on standard DAVE's kit for the AXEL ULite SOM:

From imx6ul-axelulite.dtsi:

&usdhc1 {
        pinctrl-names = "default";
        pinctrl-0 = <&pinctrl_usdhc1>;
        cd-gpios = <&gpio1 19 GPIO_ACTIVE_LOW>;
        bus-width = <4>;
        no-1-8-v;
        keep-power-in-suspend;
        enable-sdio-wakeup;
        status = "okay";
};
...
...
&iomuxc {
...
...
        pinctrl_usdhc1: usdhc1grp {
            fsl,pins = <
                MX6UL_PAD_SD1_CMD__USDHC1_CMD       0x17059
                MX6UL_PAD_SD1_CLK__USDHC1_CLK       0x10071
                MX6UL_PAD_SD1_DATA0__USDHC1_DATA0   0x17059
                MX6UL_PAD_SD1_DATA1__USDHC1_DATA1   0x17059
                MX6UL_PAD_SD1_DATA2__USDHC1_DATA2   0x17059
                MX6UL_PAD_SD1_DATA3__USDHC1_DATA3   0x17059
                MX6UL_PAD_UART1_RTS_B__GPIO1_IO19   0x17059     /* SD1 CD */
            >;
        };
...
...
};

The USDHC interface is re-configured on the carrier device tree because of the Card Detect pin (which is related to the real board hardware implementation).

RIALTO SBC

Here below is an example of device tree configuration used on standard DAVE's kit for the RIALTO SBC:

From imx6ul-axelulite.dtsi:

&usdhc1 {
	pinctrl-names = "default";
	pinctrl-0 = <&pinctrl_usdhc1>;
	cd-gpios = <&gpio1 19 GPIO_ACTIVE_LOW>;
	no-1-8-v;
	keep-power-in-suspend;
	enable-sdio-wakeup;
	status = "okay";
};
...
...
&iomuxc {
...
...
		pinctrl_usdhc1: usdhc1grp {
			fsl,pins = <
				MX6UL_PAD_SD1_CMD__USDHC1_CMD       0x17059
				MX6UL_PAD_SD1_CLK__USDHC1_CLK       0x10071
				MX6UL_PAD_SD1_DATA0__USDHC1_DATA0   0x17059
				MX6UL_PAD_SD1_DATA1__USDHC1_DATA1   0x17059
				MX6UL_PAD_SD1_DATA2__USDHC1_DATA2   0x17059
				MX6UL_PAD_SD1_DATA3__USDHC1_DATA3   0x17059
				MX6UL_PAD_UART1_RTS_B__GPIO1_IO19   0x17059	/* SD2 CD */
			>;
		};
...
...
};

The USDHC interface is re-configured on the carrier device tree because of the Card Detect pin (which is related to the real board hardware implementation).

Accessing the peripheral in Axel ULite SOM

Once initialized, the SD device is mapped to the standard /dev/mmcblk0pX block device, depending on how many partitions are created on the SD card.

Linux messages at boot time

If the microSd card is inserted at boot time, the kernel - once the USDHC interface has been initialized - prints the device information and the partition detected like p1, p2, etc.:

...
...
[    2.394568] sdhci-esdhc-imx 2190000.mmc: Got CD GPIO
[    2.451067] mmc0: SDHCI controller on 2190000.mmc [2190000.mmc] using ADMA
[    2.501056] mmc0: host does not support reading read-only switch, assuming write-enable
[    2.512002] mmc0: new high speed SDHC card at address 5048
[    2.521767] mmcblk0: mmc0:5048 SD32G 28.9 GiB 
[    2.546074]  mmcblk0: p1 p2
[    3.055471] EXT4-fs (mmcblk0p2): mounting ext3 file system using the ext4 subsystem
[    3.139912] EXT4-fs (mmcblk0p2): recovery complete
[    3.146027] EXT4-fs (mmcblk0p2): mounted filesystem with ordered data mode. Opts: (null). Quota mode: none.
[    7.093243] EXT4-fs (mmcblk0p2): re-mounted. Opts: (null). Quota mode: none.
...
...

Additional information

If the root file system configuration does not automatically mount the partition, it is possible to mount the device using the following command:

root@desk-mx6ul-axelulite:~# mkdir -p /mnt/boot
root@desk-mx6ul-axelulite:~# mount /dev/mmcblk0p1 /mnt/boot/
root@desk-mx6ul-axelulite:~# ls /mnt/boot/
'System Volume Information'   boot.scr   imx6ul-axelulite-cb003a.dtb   imx6ul-axelulite-cb006c.dtb   splash_image.bmp   uImage
root@desk-mx6ul-axelulite:~#

and then the mounted partition is available on the /mnt/boot root file system directory.

Accessing the peripheral in RIALTO SBC

Once initialized, the SD device is mapped to the standard /dev/mmcblk0pX block device, depending on how many partitions are created on the SD card.

Linux messages at boot time

If the microSd card is inserted at boot time, the kernel - once the USDHC interface has been initialized - prints the device information and the partition detected like p1, p2, etc.:

...
...
[    2.664756] sdhci: Secure Digital Host Controller Interface driver
[    2.671049] sdhci: Copyright(c) Pierre Ossman
[    2.675429] sdhci-pltfm: SDHCI platform and OF driver helper
[    2.683712] sdhci-esdhc-imx 2190000.mmc: Got CD GPIO
[    2.752188] mmc0: SDHCI controller on 2190000.mmc [2190000.mmc] using ADMA
[    2.819418] mmc0: host does not support reading read-only switch, assuming write-enable
[    2.837977] mmc0: new high speed SDHC card at address aaaa
[    2.856731] mmcblk0: mmc0:aaaa SA16G 14.8 GiB
[    3.404407] EXT4-fs (mmcblk0p2): mounted filesystem with ordered data mode. Opts: (null). Quota mode: none.
[    3.414605] VFS: Mounted root (ext4 filesystem) on device 179:2.
[    7.470880] EXT4-fs (mmcblk0p2): re-mounted. Opts: (null). Quota mode: none.
...
...

Additional information

If the root file system configuration does not automatically mount the partition, it is possible to mount the device using the following command:

root@desk-mx6ul-rialto:~# mkdir -p /mnt/boot
root@desk-mx6ul-rialto:~# mount /dev/mmcblk0p1 /mnt/boot/
root@desk-mx6ul-rialto:~# ls /mnt/boot/
'System Volume Information'   boot.scr   imx6ul-lynx-som0022-cb0090.dtb   linux_testfile.txt   splash_image.bmp   uImage   uboot_testfile.txt
root@desk-mx6ul-rialto:~#

and then the mounted partition is available on the /mnt/boot root file system directory.

---

Peripheral UART

Device tree configuration

AXEL ULite SOM

Here below is an example of device tree configuration used on standard DAVE's kit for the AXEL ULite SOM:

From the Carrier imx6ul-axelulite-cb003a.dts device tree:

&uart3 {
        pinctrl-names = "default";
        pinctrl-0 = <&pinctrl_uart3>;
        status = "okay";
};
...
...
&iomuxc {
        pinctrl-names = "default";
        pinctrl-0 = <&pinctrl_hog_gpios>;

        imx6ul-axelulite {
...
...
        uart {
                pinctrl_uart3: uart3grp {
                        fsl,pins = <
                                MX6UL_PAD_UART3_RX_DATA__UART3_DCE_RX   0x1b0b1
                                MX6UL_PAD_UART3_TX_DATA__UART3_DCE_TX   0x1b0b1
                        >;
                };
        };
...
...

RIALTO SBC

Here below is an example of device tree configuration used on standard DAVE's kit for the RIALTO SBC:

From the SOMimx6ul-lynx-som0022.dtsi device tree:

...
...
&uart3 {
	pinctrl-names = "default";
	pinctrl-0 = <&pinctrl_uart3>;
	status = "disabled";
};
...
...
&iomuxc {
...
...

		pinctrl_uart3: uart3grp {
			fsl,pins = <
				MX6UL_PAD_UART3_TX_DATA__UART3_DCE_TX 0x1b0a1
				MX6UL_PAD_UART3_RX_DATA__UART3_DCE_RX 0x1b0a1
			>;
		};
...
...
		pinctrl_uart2: uart2grp {
			fsl,pins = <
				MX6UL_PAD_UART2_TX_DATA__UART2_DCE_TX 0x1b0a1
				MX6UL_PAD_UART2_RX_DATA__UART2_DCE_RX 0x1b0a1
			>;
		};
...
...

From the Carrier imx6ul-lynx-som0022-cb0090.dts device tree:

...
...
/* RS485 on J3 of RTIN add-on */
&uart2 {
	pinctrl-names = "default";
	pinctrl-0 = <&pinctrl_uart2>;
	status = "okay";
};

/* RS232 on J67 */
&uart3 {
	status = "okay";
};

/* RS485 on J4 of RTIN add-on */
&uart5 {
	pinctrl-names = "default";
	pinctrl-0 = <&pinctrl_uart5>;
	status = "okay";
};
...
...
&iomuxc {
...
...

		pinctrl_uart5: uart5grp {
			fsl,pins = <
				MX6UL_PAD_GPIO1_IO04__UART5_DCE_TX	0x1b0a1
				MX6UL_PAD_GPIO1_IO05__UART5_DCE_RX	0x1b0a1
			>;
		};
...
...
		pinctrl_uart2: uart2grp {
			fsl,pins = <
				MX6UL_PAD_UART2_TX_DATA__UART2_DCE_TX 0x1b0a1
				MX6UL_PAD_UART2_RX_DATA__UART2_DCE_RX 0x1b0a1
			>;
		};

...
...

Accessing the peripheral in AXEL ULite SOM

Linux messages at boot time

...
...
[    0.569198] 2020000.serial: ttymxc0 at MMIO 0x2020000 (irq = 30, base_baud = 5000000) is a IMX
[    1.344706] 21ec000.serial: ttymxc2 at MMIO 0x21ec000 (irq = 65, base_baud = 5000000) is a IMX
...
...

Usage with stty

N.B. UART mapping respect to ttymxcX is the following one:

UART1 <-> ttymxc0
UART2 <-> ttymxc1
UART3 <-> ttymxc2
UART4 <-> ttymxc3
UART5 <-> ttymxc4
UART6 <-> ttymxc5
UART7 <-> ttymxc6
UART8 <-> ttymxc7
...

For example, using a loopback HW connection (RX short-circuited to TX on UART232 port) it is possible to test the send and receive data using the ttymxc2 device:

root@desk-mx6ul-axelulite:~# stty -F /dev/ttymxc2 115200 -echo
root@desk-mx6ul-axelulite:~# cat /dev/ttymxc2 &
[1] 267
root@desk-mx6ul-axelulite:~# echo "Test loopback" > /dev/ttymxc2
Test loopback

Accessing the peripheral in RIALTO SBC

Linux messages at boot time

...
...
[    1.332721] 21e8000.serial: ttymxc1 at MMIO 0x21e8000 (irq = 65, base_baud = 5000000) is a IMX
[    1.343551] 21ec000.serial: ttymxc2 at MMIO 0x21ec000 (irq = 66, base_baud = 5000000) is a IMX
[    1.354436] 21f4000.serial: ttymxc4 at MMIO 0x21f4000 (irq = 67, base_baud = 5000000) is a IMX
...
...

Usage with stty

N.B. UART mapping respect to ttymxcX is the following one:

UART1 <-> ttymxc0
UART2 <-> ttymxc1
UART3 <-> ttymxc2
UART4 <-> ttymxc3
UART5 <-> ttymxc4
UART6 <-> ttymxc5
UART7 <-> ttymxc6
UART8 <-> ttymxc7
...

For example, to use UART232, using a loopback HW connection (RX short-circuited to TX on UART232) it is possible to test the send and receive data using the ttymxc2 device:

root@desk-mx6ul-rialto:~# stty -F /dev/ttymxc2 115200 -echo
root@desk-mx6ul-rialto:~# cat /dev/ttymxc2 &
[1] 313
root@desk-mx6ul-rialto:~# echo "Test loopback RS232" > /dev/ttymxc2
root@desk-mx6ul-rialto:~# Test loopback RS232

For example, to use UART485, using a loopback HW connection (RX short-circuited to TX of UART285 on J3 and J4 of RTIN add-on ) it is possible to test the send and receive data using the ttymxc1 and ttymxc4 device:

root@desk-mx6ul-rialto:~# stty -F /dev/ttymxc1 115200 -echo
root@desk-mx6ul-rialto:~# stty -F /dev/ttymxc4 115200 -echo
root@desk-mx6ul-rialto:~# cat /dev/ttymxc4 &
[2] 316
root@desk-mx6ul-rialto:~# cat /dev/ttymxc1 &
[3] 317
root@desk-mx6ul-rialto:~# echo "Send message from ttymxc1 to ttymxc4!" > /dev/ttymxc1
Send message from ttymxc1 to ttymxc4!
root@desk-mx6ul-rialto:~# echo "Send message from ttymxc4 to ttymxc1!" > /dev/ttymxc4
Send message from ttymxc4 to ttymxc1!

Additional information

Serial ports can be used through the standard serial programming API.

For detailed information, please refer to the Serial Programming HOWTO at Serial-Programming-HOWTO

---

Peripheral USB Host

The USB Host port requires to configure the USB VBUS regulator and the gpio used for enabling the 5V USB power switch.

Device tree configuration

AXEL ULite SOM

Here below is an example of device tree configuration used on standard DAVE's kit for the AXEL ULite SOM:

From imx6ul-axelulite-cb003a.dts:

        reg_usb_otg1_vbus: regulator@2 {
                compatible = "regulator-fixed";
                reg = <2>;
                pinctrl-names = "default";
                pinctrl-0 = <&pinctrl_usb_otg1>;
                regulator-name = "usb_otg1_vbus";
                regulator-min-microvolt = <5000000>;
                regulator-max-microvolt = <5000000>;
                gpio = <&gpio1 18 GPIO_ACTIVE_HIGH>;
                enable-active-high;
        };
...
...
&usbotg1 {
        vbus-supply = <&reg_usb_otg1_vbus>;
        disable-over-current;
        dr_mode = "host";
        status = "okay";
};
...
...
&iomuxc {
        pinctrl-0 = <&pinctrl_hog_gpios>;
        imx6ul-axelulite {
...
...
                pinctrl_usb_otg1: usbotg1grp {
                        fsl,pins = <
                                MX6UL_PAD_UART1_CTS_B__GPIO1_IO18       0x10b0          /* HOST PWR */
                                MX6UL_PAD_GPIO1_IO03__GPIO1_IO03        0x10b0          /* HOST OC */
                        >;
                };
};

RIALTO SBC

Here below is an example of device tree configuration used on standard DAVE's kit for the RIALTO SBC:

From imx6ul-lynx-som0022.dtsi:

...
...
		reg_usb_otg1_vbus: regulator@2 {
			compatible = "regulator-fixed";
			reg = <2>;
			pinctrl-names = "default";
			pinctrl-0 = <&pinctrl_usb_otg1>;
			regulator-name = "usb_otg1_vbus";
			regulator-min-microvolt = <5000000>;
			regulator-max-microvolt = <5000000>;
			gpio = <&gpio2 8 GPIO_ACTIVE_HIGH>;
			enable-active-high;
			vin-supply = <&swbst_reg>;
		};

		reg_usb_otg2_vbus: regulator@3 {
			compatible = "regulator-fixed";
			reg = <3>;
			pinctrl-names = "default";
			pinctrl-0 = <&pinctrl_usb_otg2>;
			regulator-name = "usb_otg2_vbus";
			regulator-min-microvolt = <5000000>;
			regulator-max-microvolt = <5000000>;
			gpio = <&gpio2 12 GPIO_ACTIVE_HIGH>;
			enable-active-high;
		};
...
...
&usbotg1 {
	pinctrl-names = "default";
	pinctrl-0 = <&pinctrl_usb_otg1_id>;
	vbus-supply = <&reg_usb_otg1_vbus>;
	dr_mode = "otg";
	srp-disable;
	hnp-disable;
	adp-disable;
	status = "disabled";
};

&usbotg2 {
	vbus-supply = <&reg_usb_otg2_vbus>;
	dr_mode = "host";
	status = "disabled";
};

...
...
&iomuxc {
...
...
		pinctrl_usb_otg1_id: usbotg1idgrp {
			fsl,pins = <
				MX6UL_PAD_GPIO1_IO00__ANATOP_OTG1_ID	0x17059
			>;
		};

		pinctrl_usb_otg1: usbotg1grp {
			fsl,pins = <
				MX6UL_PAD_JTAG_MOD__GPIO1_IO10		0x10b0 /* OTG1 PWR */
				MX6UL_PAD_UART3_RX_DATA__GPIO1_IO25	0x17059 /* OTG1_OC */
			>;
		};

		pinctrl_usb_otg1_1: usbotg1grp-1 {
			fsl,pins = <
				MX6UL_PAD_JTAG_MOD__GPIO1_IO10		0x10b0 /* OTG1 PWR */
				MX6UL_PAD_SNVS_TAMPER6__GPIO5_IO06	0x17059 /* OTG1_OC */
			>;
		};

		pinctrl_usb_otg2_1: usbotg2grp-1 {
			fsl,pins = <
				MX6UL_PAD_UART3_CTS_B__GPIO1_IO26	0x17059 /* OTG2_PWR */
				MX6UL_PAD_UART3_RTS_B__GPIO1_IO27	0x17059 /* OTG2_OC */
			>;
		};

...
...
};

From imx6ul-lynx-som0022-cb0090.dts:

...
...
&reg_usb_otg1_vbus {
	pinctrl-0 = <&pinctrl_usb_otg1_1>;
	gpio = <&gpio1 10 GPIO_ACTIVE_HIGH>;
};

&reg_usb_otg2_vbus {
	pinctrl-0 = <&pinctrl_usb_otg2_1>;
	gpio = <&gpio1 26 GPIO_ACTIVE_HIGH>;
};

&usbotg1 {
	disable-over-current;		// only GPIO support for OVERCURRENT in this board
	status = "okay";
};

&usbotg2 {
	disable-over-current;		// only GPIO support for OVERCURRENT in this board
	status = "okay";
};
...
...

Accessing the peripheral in AXEL ULite SOM

Linux messages at boot time

When a USB peripheral is inserted, in the following example a memory mass storage device, the kernel recognizes the device (i.e. xlass, vendor id, product id, etc.)

[   86.473658] usb 1-1: new high-speed USB device number 3 using ci_hdrc
[   86.675550] usb 1-1: New USB device found, idVendor=0781, idProduct=5571, bcdDevice= 1.27
[   86.684007] usb 1-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[   86.691304] usb 1-1: Product: Cruzer Fit
[   86.695450] usb 1-1: Manufacturer: SanDisk
[   86.699614] usb 1-1: SerialNumber: 4C530009810318107583
[   86.725892] usb-storage 1-1:1.0: USB Mass Storage device detected
[   86.753934] scsi host0: usb-storage 1-1:1.0
[   87.767002] scsi 0:0:0:0: Direct-Access     SanDisk  Cruzer Fit       1.27 PQ: 0 ANSI: 6
[   87.798198] sd 0:0:0:0: [sda] 15633408 512-byte logical blocks: (8.00 GB/7.45 GiB)
[   87.815358] sd 0:0:0:0: [sda] Write Protect is off
[   87.820216] sd 0:0:0:0: [sda] Mode Sense: 43 00 00 00
[   87.842071] sd 0:0:0:0: [sda] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
[   87.896511]  sda: sda1
[   87.899997] sd 0:0:0:0: [sda] Attached SCSI removable disk

Additional information

If the root file system configuration does not automatically mount the partition, it is possible to mount the device using the following command:

root@desk-mx6ul-axelulite:~# mkdir -p /mnt/usb
root@desk-mx6ul-axelulite:~# mount /dev/sda1 /mnt/usb/
[  155.120175] FAT-fs (sda1): Volume was not properly unmounted. Some data may be corrupt. Please run fsck.
root@desk-mx6ul-axelulite:~# ls -la /mnt/usb/
total 4252
drwxr-xr-x 7 root root    4096 Jan  1  1970  .
drwxr-xr-x 4 root root    4096 Dec 12 15:42  ..
drwxr-xr-x 2 root root    4096 Nov 28  2024 'System Volume Information'
-rwxr-xr-x 1 root root   50113 Dec 10 17:16  imx93-aura-som0002-cb2004.dtb
drwxr-xr-x 2 root root    4096 Dec 10 17:39  www
root@desk-mx6ul-axelulite:~#

Accessing the peripheral in RIALTO SBC

Linux messages at boot time

When a USB peripheral is inserted, in the following example a memory mass storage device, the kernel recognizes the device (i.e. class, vendor id, product id, etc.)

[ 3198.828827] usb 1-1: new high-speed USB device number 2 using ci_hdrc
[ 3199.031869] usb 1-1: New USB device found, idVendor=125f, idProduct=c08a, bcdDevice= 1.00
[ 3199.031980] usb 1-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[ 3199.032042] usb 1-1: Product: ADATA USB Flash Drive
[ 3199.032086] usb 1-1: Manufacturer: ADATA
[ 3199.032131] usb 1-1: SerialNumber: 11B15033223000B1
[ 3199.051776] usb-storage 1-1:1.0: USB Mass Storage device detected
[ 3199.084045] scsi host0: usb-storage 1-1:1.0
[ 3200.091305] scsi 0:0:0:0: Direct-Access     ADATA    USB Flash Drive  0.00 PQ: 0 ANSI: 2
[ 3200.110289] sd 0:0:0:0: [sda] 7892992 512-byte logical blocks: (4.04 GB/3.76 GiB)
[ 3200.110969] sd 0:0:0:0: [sda] Write Protect is off
[ 3200.111006] sd 0:0:0:0: [sda] Mode Sense: 00 00 00 00
[ 3200.111582] sd 0:0:0:0: [sda] Asking for cache data failed
[ 3200.111615] sd 0:0:0:0: [sda] Assuming drive cache: write through
[ 3200.125359]  sda: sda1
[ 3200.139266] sd 0:0:0:0: [sda] Attached SCSI removable disk

Additional information

If the root file system configuration does not automatically mount the partition, it is possible to mount the device using the following command:

root@desk-mx6ul-rialto:~# mkdir -p /mnt/usb
root@desk-mx6ul-rialto:~# mount /dev/sda1 /mnt/usb
root@desk-mx6ul-rialto:~# ls -la /mnt/usb/
total 217048
drwxr-xr-x 3 root root      4096 Jan  1  1970  .
drwxr-xr-x 4 root root      4096 Apr 28 20:56  ..
drwxr-xr-x 2 root root      4096 May 29  2024 'System Volume Information'
root@desk-mx6ul-rialto:~#

---

Peripheral USB OTG

The USB OTG ports can be configured as Host or Device mode depending on the device tree configuration. In OTG mode they can be easily tested using the Mass Storage Gadget, which lets the device export a file as a mass storage device to the connected PC.

The USB OTG peripheral is NOT available - as default option - on AXEL ULite EVK. Please contact Sales department for this option. This peripheral is available on the i.MX6UL standard product RIALTO SBC

Device tree configuration

RIALTO SBC

Here below is an example of device tree configuration used on standard DAVE's kit for the AXEL ULite SOM where USB OTG1 is configured as otg while the USB OTG2 port is configured in host mode:

From imx6ul-lynx-som0022.dtsi:

...
...
&usbotg1 {
	pinctrl-names = "default";
	pinctrl-0 = <&pinctrl_usb_otg1_id>;
	vbus-supply = <&reg_usb_otg1_vbus>;
	dr_mode = "otg";
	srp-disable;
	hnp-disable;
	adp-disable;
	status = "disabled";
};

&usbotg2 {
	vbus-supply = <&reg_usb_otg2_vbus>;
	dr_mode = "host";
	status = "disabled";
};
...
...
&iomuxc {
...
...
		pinctrl_usb_otg1_1: usbotg1grp-1 {
			fsl,pins = <
				MX6UL_PAD_JTAG_MOD__GPIO1_IO10		0x10b0 /* OTG1 PWR */
				MX6UL_PAD_SNVS_TAMPER6__GPIO5_IO06	0x17059 /* OTG1_OC */
			>;
		};
...
...
};

From imx6ul-lynx-som0022-cb0090.dts:

...
...
&reg_usb_otg1_vbus {
	pinctrl-0 = <&pinctrl_usb_otg1_1>;
	gpio = <&gpio1 10 GPIO_ACTIVE_HIGH>;
};

&reg_usb_otg2_vbus {
	pinctrl-0 = <&pinctrl_usb_otg2_1>;
	gpio = <&gpio1 26 GPIO_ACTIVE_HIGH>;
};

&usbotg1 {
	disable-over-current;		// only GPIO support for OVERCURRENT in this board
	status = "okay";
};

&usbotg2 {
	disable-over-current;		// only GPIO support for OVERCURRENT in this board
	status = "okay";
};
...
...

Accessing the peripheral in RIALTO SBC

Linux messages at boot time

...
...
[ 3822.510915] ci_hdrc ci_hdrc.0: EHCI Host Controller
[ 3822.511081] ci_hdrc ci_hdrc.0: new USB bus registered, assigned bus number 2
[ 3822.538895] ci_hdrc ci_hdrc.0: USB 2.0 started, EHCI 1.00
[ 3822.540643] usb usb2: New USB device found, idVendor=1d6b, idProduct=0002, bcdDevice= 5.15
[ 3822.540746] usb usb2: New USB device strings: Mfr=3, Product=2, SerialNumber=1
[ 3822.540812] usb usb2: Product: EHCI Host Controller
[ 3822.540858] usb usb2: Manufacturer: Linux 5.15.71-desk-mx6ul-l-4.2.0-rc1+g09351f1d762a ehci_hcd
[ 3822.540907] usb usb2: SerialNumber: ci_hdrc.0
[ 3822.561551] hub 2-0:1.0: USB hub found
[ 3822.561824] hub 2-0:1.0: 1 port detected
...
...

Usage in Host mode

When a USB peripheral is inserted, in the following example a memory mass storage device, the kernel recognizes the device (i.e. class, vendor id, product id, etc.)

[ 3999.798783] usb 2-1: new high-speed USB device number 2 using ci_hdrc
[ 4000.000961] usb 2-1: New USB device found, idVendor=0781, idProduct=557d, bcdDevice= 1.00
[ 4000.009839] usb 2-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[ 4000.026275] usb 2-1: Product: Cruzer Force
[ 4000.034961] usb 2-1: Manufacturer: SanDisk
[ 4000.043548] usb 2-1: SerialNumber: 03021401121621082422
[ 4000.070921] usb-storage 2-1:1.0: USB Mass Storage device detected
[ 4000.109120] scsi host1: usb-storage 2-1:1.0
[ 4001.131262] scsi 1:0:0:0: Direct-Access     SanDisk  Cruzer Force     1.00 PQ: 0 ANSI: 6
[ 4001.155899] sd 1:0:0:0: [sdb] 60088320 512-byte logical blocks: (30.8 GB/28.7 GiB)
[ 4001.180363] sd 1:0:0:0: [sdb] Write Protect is off
[ 4001.207039] sd 1:0:0:0: [sdb] Mode Sense: 43 00 00 00
[ 4001.218222] sd 1:0:0:0: [sdb] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
[ 4001.270832]  sdb: sdb1
[ 4001.295366] sd 1:0:0:0: [sdb] Attached SCSI removable disk

Usage with mass-storage

root@desk-mx6ul-rialto:~# dd if=/dev/zero of=mass_storage count=32 bs=1M
32+0 records in
32+0 records out
33554432 bytes (34 MB, 32 MiB) copied, 0.570367 s, 58.8 MB/s
root@desk-mx6ul-rialto:~# mkfs.msdos mass_storage
mkfs.fat 4.2 (2021-01-31)
root@desk-mx6ul-rialto:~# mkdir loop
root@desk-mx6ul-rialto:~# mount -o loop mass_storage loop
[ 4130.830326] loop0: detected capacity change from 0 to 65536
root@desk-mx6ul-rialto:~# echo "Test USB OTG with mass storage device" > loop/usb.txt
root@desk-mx6ul-rialto:~# umount loop/

then insert the g_mass_storage kernel module driver enabling an Windows PC to see it as a removable device

root@desk-mx6ul-rialto:~# modprobe g_mass_storage removable=y file=mass_storage
[ 4215.960825] Mass Storage Function, version: 2009/09/11
[ 4215.966024] LUN: removable file: (no medium)
[ 4215.981660] LUN: removable file: /home/root/mass_storage
[ 4215.987023] Number of LUNs=1
[ 4215.999126] g_mass_storage gadget: Mass Storage Gadget, version: 2009/09/11
[ 4216.006139] g_mass_storage gadget: userspace failed to provide iSerialNumber
[ 4216.015682] g_mass_storage gadget: g_mass_storage ready
root@desk-mx6ul-rialto:~#

Once the USB cable is connected to the PC, the storage is mounted and the usb.txt file is available:

$ cat /media/tomzy/42D5-CBA5/usb.txt 
Test USB OTG with mass storage device

The Windows PC also activates the driver and the disk is available as a Drive Unit (with the usb.txt file available).

Additional information

More information about Mass Storage Gadget driver is given in the kernel tree under Documentation/usb/mass-storage.rst

Peripheral GPIOs

i.MX6UL can handle external pins in many different ways and most of them can be configured as GPIOs. When a pin is set as a GPIO, it is possible to read its value, change its direction or change output value directly from the shell.

There aren't GPIOs configured in the AXEL ULite EVK Here below an example of GPIOs usage in the i.MX6UL standard product RIALTO SBC

Device tree configuration

RIALTO SBC

Here below is an example of device tree configuration for using the:

• RS-485 GPIOs
• Relè
• GPIO Push Button on Mezzanine Board
• LEDs on Mezzanine Board

From imx6ul-lynx-som0022-cb0090.dts:

...
...
	leds {
		compatible = "gpio-leds";
		can_term {
			label = "can_term";
			gpios = <&gpio3 3 0>;
			default-state = "off";
		};

		uart2_en {
			label = "uart2_en";
			gpios = <&gpio1 22 0>;
			default-state = "on";
		};

		uart5_en {
			label = "uart5_en";
			gpios = <&gpio1 23 0>;
			default-state = "on";
		};
...
...
gpio-push-button {
		compatible = "gpio-keys";
		pinctrl-names = "default";
		pinctrl-0 = <&pinctrl_gpio_push_button>;
		status = "okay";
		f1 {
			label = "GPIO F1";
			gpios = <&gpio3 1 GPIO_ACTIVE_LOW>;
			linux,code = <KEY_F1>;
		};
	};

};
...
...

&i2c2 {
	status = "okay";
...
...
	pca9551@60 {
		pinctrl-names = "default";
		pinctrl-0 = <&pinctrl_pca60>;
		compatible = "nxp,pca9551";
		reg = <0x60>;
		#address-cells = <1>;
		#size-cells = <0>;
		reset-gpios = <&gpio3 22 GPIO_ACTIVE_LOW>;

		led@4 {
			label = "led2";
			reg = <4>;
			retain-state-shutdown;
			default-state = "keep";
			type = <PCA955X_TYPE_LED>;
		};

		led@5 {
			label = "led1";
			reg = <5>;
			retain-state-shutdown;
			default-state = "keep";
			type = <PCA955X_TYPE_LED>;
		};
	};
...
...
};
...
...
&iomuxc {
...
...
	imx6ul-lynx {
		pinctrl_hog_gpios: hoggrp-gpios {
			fsl,pins = <
				MX6UL_PAD_GPIO1_IO08__WDOG1_WDOG_B	0x0b0b1		/* WD RESET */
				MX6UL_PAD_GPIO1_IO01__GPIO1_IO01	0x1b0b1
				MX6UL_PAD_GPIO1_IO02__GPIO1_IO02	0x4001b0b1	/* Enable SION bit */
				MX6UL_PAD_GPIO1_IO03__GPIO1_IO03	0x4001b0b1	/* Enable SION bit */
				MX6UL_PAD_CSI_DATA04__GPIO4_IO25	0x1b0b1
				MX6UL_PAD_CSI_DATA05__GPIO4_IO26	0x1b0b1
				MX6UL_PAD_CSI_DATA06__GPIO4_IO27	0x1b0b1
				MX6UL_PAD_LCD_VSYNC__GPIO3_IO03		0x1b0b1 /* FlexCAN SW Termination */
				MX6UL_PAD_LCD_HSYNC__GPIO3_IO02		0x1b0b1 /* UART3 RS485 SW Termination */
				MX6UL_PAD_UART2_CTS_B__GPIO1_IO22	0x1b0b1 /* UART2 RS485 on RTIN enable */
				MX6UL_PAD_UART2_RTS_B__GPIO1_IO23	0x1b0b1 /* UART5 RS485 on RTIN enable */
			>;
		};

		pinctrl_gpio_push_button: gpio_push_button {
			fsl,pins = <
				MX6UL_PAD_LCD_RESET__GPIO3_IO04		0x1b0b0		/*KEY1*/
				MX6UL_PAD_LCD_ENABLE__GPIO3_IO01	0x1b0b0		/*KEY0*/
			>;
		};

...
...
};

Accessing the peripheral in RIALTO SBC

Using LEDs on Mezzanine Board

To blink LED1 on Mezzanine Board send the following commands

root@desk-mx6ul-rialto:~# echo 255 > /sys/class/leds/pca955x\:led1/brightness
root@desk-mx6ul-rialto:~# echo 0 > /sys/class/leds/pca955x\:led1/brightness
</pre>

To blink LED2 on Mezzanine Board send the following commands
<pre>
root@desk-mx6ul-rialto:~# echo 255 > /sys/class/leds/pca955x\:led2/brightness
root@desk-mx6ul-rialto:~# echo 0 > /sys/class/leds/pca955x\:led2/brightness

Using GPIO Push Button on Mezzanine Board

Pressing the Button generates the following event

root@desk-mx6ul-rialto:~# evtest /dev/input/event0
Input driver version is 1.0.1
Input device ID: bus 0x19 vendor 0x1 product 0x1 version 0x100
Input device name: "gpio-push-button"
Supported events:
  Event type 0 (EV_SYN)
  Event type 1 (EV_KEY)
    Event code 59 (KEY_F1)
Properties:
Testing ... (interrupt to exit)
[ 5332.805492] evbug: Event. Dev: input0, Type: 1, Code: 59, Value: 1
[ 5332.811800] evbug: Event. Dev: input0, Type: 0, Code: 0, Value: 0
Event: time 1651181469.356509, type 1 (EV_KEY), code 59 (KEY_F1), value 1
Event: time 1651181469.356509, -------------- SYN_REPORT ------------
[ 5333.103596] evbug: Event. Dev: input0, Type: 1, Code: 59, Value: 0
[ 5333.109908] evbug: Event. Dev: input0, Type: 0, Code: 0, Value: 0
Event: time 1651181469.654611, type 1 (EV_KEY), code 59 (KEY_F1), value 0
Event: time 1651181469.654611, -------------- SYN_REPORT ------------

Using Relé on RTIN add-on

• set GPIO1_IO01 as output GPIO
  • GPIO1_IO01 => (n-1)*32 + IO = (1-1)*32+1 = 1
  • to enable and disable relè, with sysfs, use the command here below

    root@desk-mx6ul-rialto:~# echo 1 > /sys/class/gpio/export
    root@desk-mx6ul-rialto:~# echo out > /sys/class/gpio/gpio1/direction
    root@desk-mx6ul-rialto:~# echo 1 > /sys/class/gpio/gpio1/value
    root@desk-mx6ul-rialto:~# echo 0 > /sys/class/gpio/gpio1/value
    

  • to enable and disable relè, with libgpiod, use the command here below

    root@desk-mx6ul-rialto:~# gpioset gpiochip0 1=1
    root@desk-mx6ul-rialto:~# gpioset gpiochip0 1=0
    

• set GPIO2_IO02 as output GPIO
  • GPIO2_IO02 => (n-1)*32 + IO = (1-1)*32+2 = 2
  • to enable and disable relè, with sysfs, use the command here below

    root@desk-mx6ul-rialto:~# echo 2 > /sys/class/gpio/export
    root@desk-mx6ul-rialto:~# echo out > /sys/class/gpio/gpio2/direction
    root@desk-mx6ul-rialto:~# echo 1 > /sys/class/gpio/gpio2/value
    root@desk-mx6ul-rialto:~# echo 0 > /sys/class/gpio/gpio2/value
    

  • to enable and disable relè, with libgpiod, use the command here below

    root@desk-mx6ul-rialto:~# gpioset gpiochip0 2=1
    root@desk-mx6ul-rialto:~# gpioset gpiochip0 2=0
    

Using INPUT GPIO on RTIN add-on

A loopback HW connection is wired between relè and INPUT GPIO for testing purposes: the relè output sets the INPUT GPIO value.

The relè as shown in the previous chapter is set and then the INPUT GPIOs value is read.

• set GPIO4_IO26 as input GPIO
  • GPIO4_IO26 => (n-1)*32 + IO = (4-1)*32+26 = 122
  • to enable input GPIO, with sysfs, use the command here below

    root@desk-mx6ul-rialto:~# echo 122 > /sys/class/gpio/export
    root@desk-mx6ul-rialto:~# echo in > /sys/class/gpio/gpio122/direction
    root@desk-mx6ul-rialto:~# cat /sys/class/gpio/gpio122/value
    1
    

  • to read value of input GPIOs with libgpiod, use the command here below

    root@desk-mx6ul-rialto:~# gpioget gpiochip3 26
    1
    

• set GPIO4_IO27 as input GPIO
  • GPIO4_IO27 => (n-1)*32 + IO = (4-1)*32+27 = 123
  • to enable input GPIO, with sysfs, use the command here below

    root@desk-mx6ul-rialto:~# echo 123 > /sys/class/gpio/export
    root@desk-mx6ul-rialto:~# echo in > /sys/class/gpio/gpio123/direction
    root@desk-mx6ul-rialto:~# cat /sys/class/gpio/gpio123/value
    1
    

  • to read value of input GPIOs with libgpiod, use the command here below

    root@desk-mx6ul-rialto:~# gpioget gpiochip3 27
    1
    

Additional information

Information about GPIOs usage under sysfs directory https://www.kernel.org/doc/Documentation/gpio/sysfs.txt

sysfs GPIO ABI has been deprecated. Please find more information here about it. A character device access has to be used, more information here

Information about GPIOs library libgpiod - C library and tools - can be found on git.kernel.org