U-Boot, Myon II

Since Trizeps VIII Mini and Myon II are software compatible, the same bootloader may be used for both modules.

http://gitlab.keith-koep.com/imx/uboot-imx
http://gitlab.keith-koep.com/imx/imx-mkimage

Previous Versions:

This is only a quick-reference on how to build the U-Boot bootloader including Keith & Koep specific changes.
For details please view the NXP i.MX8M Mini documentation.

Get the source code of U-Boot and imx_mkimage tool from git repository:

$ mkdir uboot
$ cd uboot
~/uboot$ git clone http://gitlab.keith-koep.com/imx/imx-mkimage.git -b kuk_imx_4.14.98_2.0.0_ga
~/uboot$ git clone http://gitlab.keith-koep.com/imx/uboot-imx.git -b kuk_imx_v2018.03_4.14.98_2.0.0_ga

Setup Cross-Build environment (View Software-Development-Kit on how to install.):

$ . /opt/fsl-imx-fb/4.14-sumo/environment-setup-aarch64-poky-linux

Build U-Boot from source Code:

~/uboot/uboot-imx$ make clean
~/uboot/uboot-imx$ make myon2_defconfig
~/uboot/uboot-imx$ make all

This will generate the SPL, U-Boot and device-tree binary.
Note that this minimal device-tree binary will only be used by U-Boot and is not intended for use by the Linux kernel!
After these binaries have been created, they must be packed together with other components to form the bootloader:
SCU-Firmware: This NXP firmware is loaded into the Cortex-M4 (SCU: System Controller Unit).
ATF-Firmware: The SCU will load the ARM trusted firmware.
SPL / U-Boot: The ATF will load the primary loader, which will initialize the LPDDR4 and load U-Boot.

~/uboot/uboot-imx$ make miniflash.bin

Which will create

~/uboot/uboot-imx/miniflash.bin

If you run

~/uboot/uboot-imx$ make flash_mini

this will build the bootloader and run uuu to download the bootloader to the module.

To deploy software to Myon II, you may use the NXP Universal Update Utility (UUU).
Steps needed:

• Enter USB Serial Download Mode
• Run:

  ~/uboot-imx/iMX8M$ sudo uuu -b emmc flash.bin

Copy bootloader (flash.bin) to a filesystem accessible by Linux.

$ dd if=/dev/zero of=/dev/mmcblk0 bs=1k seek=4096 conv=fsync count=8
$ echo 0 > /sys/block/mmcblk0boot0/force_ro
$ dd if=flash.bin of=/dev/mmcblk0boot0 bs=1k seek=33
$ echo 1 > /sys/block/mmcblk0boot0/force_ro

This will:

• clear U-Boot environment-area,
• disable read-only access to the boot partition,
• write flash.bin to offset 33k and
• reenable read-only access.

To enter the bootloader command console attach a serial cable to the first COM-port ( P2_TXD/RXD pins: J70-69,J70-71) with 115k2 Baud, 8N1.
Press any key while the device is powering up.
The output should look something like this:

U-Boot SPL 2018.03-00063-g076c240b55-dirty (Oct 15 2019 - 14:56:24 +0200)
DDRINFO: start lpddr4 ddr init
DDRINFO: ddrphy calibration done
DDRINFO: ddrmix config done
Normal Boot
Trying to boot from MMC1


U-Boot 2018.03-00063-g076c240b55-dirty (Oct 15 2019 - 14:56:24 +0200)

CPU:   Freescale i.MX8MMQ rev1.0 1800 MHz (running at 1200 MHz)
CPU:   Commercial temperature grade (0C to 95C) at 56C
Reset cause: POR
Model: FSL i.MX8MM EVK board
DRAM:  2 GiB
Modul: 60A20.x01xx.Hxx
This is a Keith & Koep GmbH  Myon II V1R1 running a i.MX 8M Mini Quad 1800MHz (consumer) with 2GB,32bit RAM and booting from eMMC.
IO-Voltage 1.8V
Audio WM8983

MMC:   FSL_SDHC: 0, FSL_SDHC: 1
Loading Environment from MMC... OK
No panel detected: default to MIPI2HDMI
Display: MIPI2HDMI (1920x1080)
Video: 1920x1080x24
In:    serial
Out:   serial
Err:   serial

 BuildInfo:
  - ATF 1cb68fa
  - U-Boot 2018.03-00063-g076c240b55-dirty

switch to partitions #0, OK
mmc0(part 0) is current device
flash target is MMC:0
EXT_CSD[179], PARTITION_CONFIG:
BOOT_ACK: 0x1
BOOT_PARTITION_ENABLE: 0x1
PARTITION_ACCESS: 0x0
Net:   none (disabled)

Warning: ethernet@30be0000 (eth0) using random MAC address - 16:89:6e:97:26:5d
eth0: ethernet@30be0000
Fastboot: Normal
Normal Boot
Hit any key to stop autoboot:  0
u-boot=>

The Linux-kernel will use a Device-Tree-Binary file (.dtb) to determine how the Trizeps module is used in a system (i.e. which drivers to load).
How the device-tree is generated might depend on the used kernel-version and it is recommended to view the articles to the respective OS in this wiki.
For Linux 4.14 the device-tree files can be found at:

~/linux_imx/arch/arm64/boot/dts/keithkoep

When building the Linux-kernel .dts source-files are converted to .dtb binary files.

When you open the u-boot command prompt and output the environment, you can determine which device-tree is used:

u-boot=> env print -a
...
fdt_file=kuk-trizeps8mini.dtb
...

To change this you can i.e. call:

u-boot=> env set fdt_file kuk-myon2-ipanm7.dtb
u-boot=> env save

'env save' will store this setting for subsequent boots.

The USB Serial Download Mode (manufacturing mode) is a mode by which the i.MX8M Mini processor loads its internal ROM-firmware instead of the bootloader stored in eMMC.
It will use the USB1 port to enumerate as HID-device on a connected PC.
In this mode the NXP Universal Update Utility (UUU) can be used to deploy software.

USB Serial Download Mode is entered by setting pin J70-40 BOOT_MODE_0 to VDD_IO on boot.
On i-PAN M7 CoverLens and ConXM (formerly: dragonBase) this can be achieved by setting a switch.