U-Boot on Orange Pi 4

U-Boot used on an Orange Pi 4 which sports an RK3399 processor.

This is the first step to getting the device booted and running any software. For the actual OS installation, see Linux on Orange Pi 4.

[i] Instructions Status

• Compilation on x86_64: OK
  • Tried and tested.
• Compilation on ARMv8: Partially tested.
  • Should work with minor tweaks.
  • TODO: Finish testing and extend the instructions.

Introduction

Rockchip boot flow. Source: [1]

See U-Boot for general concepts and definitions.

U-Boot takes care of the initial booting. It is device (board) specific and so needs to be compiled specifically for Orange Pi 4 as it initializes the hardware, e.g. the RAM modules.

Internally there are 3 (!) bootloaders which form a boot chain: TPL -> SPL -> U-Boot. To boot an actual operating system, U-Boot executes the OS's bootloader, which brings this to 4 (!!) bootloaders in total. Crazy, right?

See ARM Trusted Firmware for ATF / trust related terminology.

Boot Sequence

Rockchip-specific booting is described here: [3]

1. Loader 1:
   • option 1: miniloader
   • option 2: SPL/TPL
2. Loader 2:
   • option 1: uboot.img
   • option 2: u-boot.itb
3. trust.img
4. boot.img
5. rootfs.img

(!) Option 1 (recommended by Rockchip) uses closed source tools and binaries!

rkbin/tools are pre-built x86 binaries and are therefore not usable on the target device. The source code is not available for audit or compilation on a different architecture.

Therefore this is not a usable route and will not be discussed further.

Setup

Base Build Tools

Arch Linux

• dtc (device tree compiler)
• bc (basic calculator)

TODO: Not complete. Add packages needed bases on testing on an x86_64 computer.

Ubuntu

TODO: Not complete. Add packages needed based on testing on Orange Pi 4.

Cross-compilation

This is needed only if you're not compiling on the Orange Pi 4 (or other ARMv8 device).

• Binaries for aarch64-linux-gnu: [4]

U-Boot Sources

Note on orangepi-rk3399: Though there is an orangepi-rk3399 board available, this is NOT the same as Orange Pi 4. It does have the same processor, but the device tree is different. Notably there is difference in RAM: DDR3 vs LPDDR4.

TODO: orangepi-4-rk3399 doesn't exist in mainline as of 2020-03-25, apply this patch from Armbian to add the board definition: [5]

git clone https://gitlab.denx.de/u-boot/u-boot.git
cd u-boot
make orangepi-4-rk3399_defconfig

Compilation

Export cross compiler for AArch64

Export cross compiler path for aarch64:

1. 'wget' the toolchain binaries (see above)
2. 'unxz' the archive
3. prepare 'CROSS_COMPILE'
   • 'cd gcc-linaro-.../bin'
   • 'CROSS_COMPILE_AARCH64=`pwd`'
   • 'CROSS_COMPILE=$CROSS_COMPILE_AARCH64'

The usage is this: CROSS_COMPILE=$CROSS_COMPILE (needed only when not running on the target device)

Compile ATF

	=> git clone https://github.com/ARM-software/arm-trusted-firmware.git
	=> cd arm-trusted-firmware

	(export cross compiler path for Cortex-M0 MCU likely arm-none-eabi-)
	=> make realclean
	=> make CROSS_COMPILE=$CROSS_COMPILE PLAT=rk3399

	(export bl31.elf)
	=> export BL31=/path/to/arm-trusted-firmware/build/rk3399/release/bl31/bl31.elf

Compile PMU M0 firmware (optional)

TODO: The internally provided cross-compile toolchain for cortex-m0 seems outdated (it wouldn't compile). Skipping for now.

     This is optional for most of the rk3399 boards and required only for Puma board.

     => git clone git://git.theobroma-systems.com/rk3399-cortex-m0.git
     => cd rk3399-cortex-m0

     (export cross compiler path for Cortex-M0 PMU)
     => make CROSS_COMPILE=arm-cortex_m0-eabi-

     (export rk3399m0.bin)
     => export PMUM0=/path/to/rk3399-cortex-m0/rk3399m0.bin

Compile U-Boot

U-Boot Makefile build dependencies [2]

     => cd /path/to/u-boot
     => make orangepi-4-rk3399_defconfig
     => make CROSS_COMPILE=$CROSS_COMPILE

     (Get idbloader.img and u-boot.itb)

TODO: The default CONFIG_TARGET_CHROMEBOOK_BOB=y fails to compile. Selecting CONFIG_TARGET_EVG_RK3399=y fixes this and the board successfully loads the bootloader command prompt.

Booting from an SD card

Flashing

Write tpl+spl at 64th sector

  sudo dd if=idbloader.img of=/dev/sdc seek=64

Write U-Boot proper at 16384 sector

  sudo dd if=u-boot.itb of=/dev/sdc seek=16384
  sync

Booting

Put this microSD card into your board and reset it. You should see something like:

U-Boot TPL 2020.04-rc3-00171-g0aadc0786e-dirty (Mar 27 2020 - 00:08:45)
Channel 0: LPDDR4, 50MHz
BW=32 Col=10 Bk=8 CS0 Row=15 CS1 Row=15 CS=2 Die BW=16 Size=2048MB
Channel 1: LPDDR4, 50MHz
BW=32 Col=10 Bk=8 CS0 Row=15 CS1 Row=15 CS=2 Die BW=16 Size=2048MB
256B stride
256B stride
lpddr4_set_rate: change freq to 400000000 mhz 0, 1
lpddr4_set_rate: change freq to 800000000 mhz 1, 0
Trying to boot from BOOTROM
Returning to boot ROM...

U-Boot SPL 2020.04-rc3-00171-g0aadc0786e-dirty (Mar 27 2020 - 00:08:45 +0100)
Trying to boot from MMC1


U-Boot 2020.04-rc3-00171-g0aadc0786e-dirty (Mar 27 2020 - 00:08:45 +0100)

Model: OrangePi 4 AI board
DRAM:  3.9 GiB
PMIC:  RK808 
MMC:   dwmmc@fe320000: 1, sdhci@fe330000: 0
Loading Environment from MMC... *** Warning - bad CRC, using default environment

In:    serial@ff1a0000
Out:   serial@ff1a0000
Err:   serial@ff1a0000
Model: OrangePi 4 AI board
Net:   eth0: ethernet@fe300000
Hit any key to stop autoboot:  0 
=>   

Related

• ATF = ARM Trusted Firmware
• U-Boot on Orange Pi 4 - logs

External Links

• Main resource: gitlab.denx.de/.../README.rockchip
• Rockchip ATF wiki: [6]
  • ATF repository: [7]