U-Boot

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Support for sunxi devices is increasingly available from upstream U-Boot. This page describes that support.

To know if your device is supported in U-Boot, check out the respective device page. Here is the list of all devices supporting mainline U-Boot.

A changelog is available here.

We have a separate page for the legacy sunxi branch of U-Boot.

This document is mainly for 32bits ARM device. Differences for ARM64 are only mentioned in the Compile U-Boot section. For more info see directly board/sunxi/README.sunxi64 in uboot sources.

Contents

Status Matrix

The goal of this matrix is to give an easy view of work on each SoC worked on by linux-sunxi.

Model F1C-
100s
A10 A10s A13
R8
A20 A23 A31 A33
R16
A64 A80 A83T GR8 H3 H5 H6 R40
T3
V3
V3s
S3L
MMC  ?  ?  ?  ?  ?  ?  ?  ?  ?  ?  ?  ?  ?  ?  ?  ?  ?
USB  ?  ?  ?  ?  ?  ?  ?  ?  ? NO  ?  ?  ?  ?  ?  ?  ?
NET  ?  ?  ?  ?  ?  ?  ?  ?  ? NO  ?  ?  ?  ? NO  ?  ?
  • MMC is for ability to boot from sdcard
  • USB is ability to connect USB devices (like ethernet dongle)
  • NET is ability to boot from TFTP
Legend
In U-Boot mainline since version x
Nobody works on it, but it should be compatible with already done drivers
Somebody works on it
No support, nobody works on it
support impossible
Status is unknown/to be completed


Compile U-Boot

Get a toolchain

If you haven't done so before, get a suitable toolchain installed and added to your PATH.

You may also need to add some additional packages to build U-Boot:

apt-get install swig python-dev

Get the Device-tree Compiler

Depending on your desired U-Boot version, a sufficiently up-to-date dtc may be required. (The build process will error on an outdated dtc, and request you to upgrade it.) The installation of dtc is described in the Device tree article.

If you are going to build a Linux kernel alongside U-Boot, it might also be worth to examine the kernel sources - as they come with dtc included under ${KERNEL_DIR}/scripts/dtc/.

Clone the repository

You can clone the u-boot repository by running:

git clone git://git.denx.de/u-boot.git


MBOX icon important.png You should prefer using a stable release, unless you're testing recently added boards or experimental features that have not yet made into stable release:
 git checkout v2019.10 # or whatever is latest


Determine build target

Go to your u-boot tree and search in the directory configs/ for your board, the file name looks like <board_name>_defconfig.

So, if your device is Cubieboard2 your build target is Cubieboard2_defconfig.

Build

Arm Trusted Firmware (arm64)

In order to build U-Boot for a arm64 device you need to build Arm Trusted Firmware (ATF) as a prerequisite first. Change <platform> to your needs. PLAT=sun50i_a64 for example is suitable for H5 and A64 devices. (See board/sunxi/README.sunxi64 in uboot sources for more infos.)

git clone https://github.com/ARM-software/arm-trusted-firmware.git
cd arm-trusted-firmware
make CROSS_COMPILE=aarch64-linux-gnu- PLAT=<platform> DEBUG=1 bl31

When you have determined what <board_name> just configure U-Boot with a suitable default configuration. Use menuconfing to play with the settings if you feel like it and then just build it:

armhf

make CROSS_COMPILE=arm-linux-gnueabihf- <board_name>_defconfig
make CROSS_COMPILE=arm-linux-gnueabihf- menuconfig
make CROSS_COMPILE=arm-linux-gnueabihf-

arm64

make CROSS_COMPILE=aarch64-linux-gnu- BL31=<path_to_arm-trusted-firmware>/build/sun50i_a64/debug/bl31.bin  <board_name>_defconfig
make CROSS_COMPILE=aarch64-linux-gnu- BL31=<path_to_arm-trusted-firmware>/build/sun50i_a64/debug/bl31.bin menuconfig
make CROSS_COMPILE=aarch64-linux-gnu- BL31=<path_to_arm-trusted-firmware>/build/sun50i_a64/debug/bl31.bin

(When compiling natively, omit the CROSS_COMPILE=…)

When the build has completed, there will be u-boot-sunxi-with-spl.bin available in your u-boot tree. The installation step will instruct how to install this on the installation media (e.g. a SD card), but first U-Boot needs to be configured.

Configure U-Boot

This article provides a collection of various scenarios for booting with U-Boot.

Boot

For getting these bits loaded onto the hardware, please refer to the respective howto:

Booting with boot.cmd

For booting from SD with mainline U-Boot, the recommended way is:

  • create a file boot.cmd on the first partition (also check Kernel arguments for extra 'bootargs' options):
mainline kernel sunxi-3.4 kernel
setenv bootargs console=ttyS0,115200 root=/dev/mmcblk0p2 rootwait panic=10
load mmc 0:1 0x43000000 ${fdtfile} || load mmc 0:1 0x43000000 boot/${fdtfile}
load mmc 0:1 0x42000000 uImage || load mmc 0:1 0x42000000 boot/uImage
bootm 0x42000000 - 0x43000000
setenv bootm_boot_mode sec
setenv bootargs console=ttyS0,115200 root=/dev/mmcblk0p2 rootwait panic=10
load mmc 0:1 0x43000000 script.bin || load mmc 0:1 0x43000000 boot/script.bin
load mmc 0:1 0x42000000 uImage || load mmc 0:1 0x42000000 boot/uImage
bootm 0x42000000
  • If you also want to use an initramfs, please refer to the Initial Ramdisk article for details.
Information.png If you're wondering why setting bootm_boot_mode might be necessary for older kernels, have a look at the details of PSCI.
Sticky-note-pin.png Note: Directly using a zImage is also supported by U-Boot for the sunxi platform. Substitute zImage in place of uImage in the commands above, and then use the bootz command instead of bootm.
Sticky-note-pin.png Note: In order to boot your newly created arm64 kernel, remember to use Image instead of uImage/zImage. You also have to load it with booti instead of bootm/bootz. So you have to adopt the corresponding lines in the boot.cmd file.
  • boot.cmd isn't used directly, but needs to be wrapped with uboot header with the command:

mkimage -C none -A arm -T script -d boot.cmd boot.scr

Booting with extlinux.conf

Mainline U-Boot also use syslinux/extlinux as payload.

You need to install the boot configuration file extlinux.conf in an ext2/3/4 partition of SD card and U-Boot will find and execute it. This is conceptually identical to creating a GRUB configuration file on a desktop PC.

Example extlinux.conf:

TIMEOUT 100
DEFAULT default
MENU TITLE Boot menu

LABEL default
	MENU LABEL Default
        LINUX /zImage
        FDT /sun4i-a10-marsboard.dtb
        APPEND root=/dev/sda1 rootwait console=tty0 console=ttyS0,115200n8

LABEL exit
	MENU LABEL Local boot script (boot.scr)
        LOCALBOOT 1

Setting u-boot environment variables

There is a difference in setting environment variables between the boot script and the U-Boot shell.

Inside the shell you would set, for instance:

setenv root /dev/sda1

But in the script you would use:

root=/dev/sda1

NAND

Example U-Boot environment, as found in uEnv.txt from a stock android U-Boot environment partition

bootdelay=0
bootcmd=run setargs boot_normal
console=ttyS0,115200
nand_root=/dev/nandc
mmc_root=/dev/mmcblk0p4
init=/init
loglevel=8
setargs=setenv bootargs console=${console} root=${nand_root} init=${init} loglevel=${loglevel}
boot_normal=nand read 40007800 boot;boota 40007800
boot_recovery=nand read 40007800 recovery;boota 40007800
boot_fastboot=fastboot

NFS

Recent version of U-Boot are able to boot from NFS as well as TFTP, but you have to get rid of the automatic setup of FTP. Check Ethernet for more information.

Sticky-note-pin.png Note: on the A20 based cubieboards, this only seems to work on the stable kernel, not on stage.

FB console

To get U-Boot output shown on the built-in framebuffer driver (currently, HDMI only at 1024x768), add the following to your boot.cmd:

setenv stdout=serial,vga
setenv stderr=serial,vga

The default environment has these values set as well.

LCD Settings

There is a separate wiki page about configuring LCD in U-Boot.

Install U-Boot

  • Convert the boot.cmd to boot.scr using mkimage:

armhf

 mkimage -C none -A arm -T script -d boot.cmd boot.scr

arm64

 mkimage -C none -A arm64 -T script -d boot.cmd boot.scr
  • Copy the bootloader to the installation media
 dd if=u-boot-sunxi-with-spl.bin of=/dev/sdX bs=1024 seek=8
  • copy kernel files to the first partition
    • For a 3.4 kernel you need uImage (linux kernel) and script.bin (binary representation of FEX).
    • For a device tree based kernel ("mainline", 4.x) you need the kernel image (uImage, zImage or Image) and the device-specific .dtb file (the one referenced in the ${fdtfile} above) that is generated as part of your kernel compilation.

Look at Manual build howto for more details.

Troubleshooting

USB 1.x, USB keyboards (U-Boot < v2015.07)

U-Boot v2015.07 and later shouldn't have problems supporting mixed USB 1.x/2.0 devices. OHCI and EHCI no longer conflict with each other (after the switch to device model).

Previous U-Boot versions (v2015.04 and older) have a problem supporting both USB 1.x (OHCI) and USB 2.0 (EHCI) at the same time - the latter includes the SUNXI_EHCI driver for Allwinner boards.

Unfortunately, this also affects many USB HID / keyboard devices which would not be detected properly by U-Boot. The typical message in this case is "cannot reset port N!?", where N is whichever USB port those devices were attached to.

Information.png A possible workaround is to place an external USB 2.0 hub between your board and these USB devices.

See: http://lists.denx.de/pipermail/u-boot/2015-January/200162.html.

U-Boot 2015.07+ won't start

If you're using a recent (device model based) U-Boot, and the SPL just hangs after initializing the DRAM (CPU: 912000000Hz, AXI/AHB/APB: 3/2/2 or something similar), chances are that your main U-Boot binary may be missing DTB information / a proper device tree. Depending on the (possibly outdated) instructions you followed: double-check that you're not incorrectly using u-boot.bin instead of u-boot-dtb.bin, or u-boot.img instead of u-boot-dtb.img.

Legacy kernel won't start

  • If your 3.4.x kernel refuses to boot / gets stuck right after "Starting kernel ...":
  • If you don't have a serial console and only use VGA/HDMI/LCD, then it might be also the case of "Unrecognized/unsupported machine ID" (see below).

Unrecognized/unsupported machine ID

The sunxi-3.4 kernel may fail to boot with one of the following error messages on the serial console (but this message is not visible on a HDMI monitor or a LCD display!):

Error: unrecognized/unsupported machine ID (r1 = 0x10001008).
Error: unrecognized/unsupported machine ID (r1 = 0x1000102a).
Error: unrecognized/unsupported machine ID (r1 = 0x100010bb).

In this case either upgrade to a recent stage/sunxi-3.4 kernel (github branch) - or try to "Enable workarounds for booting old kernels" in U-Boot:

make menuconfig or make CROSS_COMPILE=arm-linux-gnueabihf- menuconfig, the option is located under "ARM architecture". (Make sure to rebuild your U-Boot after changing it.)

If upgrading to stage/sunxi-3.4 is not an option (i.e. using some old and very much diverged sunxi-3.4 fork is really necessary), then the following patches can be cherry-picked (= selectively merged as a set):

wget https://github.com/linux-sunxi/linux-sunxi/commit/5052b83aa44dc16d6662d8d9d936166c139ad8c5.patch
wget https://github.com/linux-sunxi/linux-sunxi/commit/9a1cd034181af628d4145202289e1993c1687db6.patch
wget https://github.com/linux-sunxi/linux-sunxi/commit/c4c4664ed1a2f35e54a33ae4e65f517721ff43b5.patch
wget https://github.com/linux-sunxi/linux-sunxi/commit/ade08aa6e5249a9e75a97393e86c250b2bcb3ec8.patch
wget https://github.com/linux-sunxi/linux-sunxi/commit/16b25a95327f45a995f6efcf3e9d83a414231af9.patch
wget https://github.com/linux-sunxi/linux-sunxi/commit/dea62f21deb177053b84b15a519dff6c74d061d9.patch
wget https://github.com/linux-sunxi/linux-sunxi/commit/d47d367036be38c5180632ec8a3ad169a4593a88.patch
git am 5052b83aa44dc16d6662d8d9d936166c139ad8c5.patch
git am 9a1cd034181af628d4145202289e1993c1687db6.patch
git am c4c4664ed1a2f35e54a33ae4e65f517721ff43b5.patch
git am ade08aa6e5249a9e75a97393e86c250b2bcb3ec8.patch
git am 16b25a95327f45a995f6efcf3e9d83a414231af9.patch
git am dea62f21deb177053b84b15a519dff6c74d061d9.patch
git am d47d367036be38c5180632ec8a3ad169a4593a88.patch

Exclamation.png It is required to apply all of them, as they contain important stability/safety changes. The last patch in this series only takes care of the safety guard, which exists there specifically to block booting problematic kernels. Just removing the safety guard alone without applying all the bugfixes will lead to obscure runtime problems, please don't be tempted to do this.


ImportError: No module named _libfdt

If you see the following error when compiling on Arch Linux arm

ImportError: No module named _libfdt

install dtc

sudo pacman -S dtc

Adding a new device to upstream U-Boot

http://lists.denx.de/pipermail/u-boot/2014-December/199351.html

DRAM Settings

Failsafe DRAM settings, based on standard JEDEC timings

Each device has DRAM settings configured in its defconfig file in the U-Boot "configs" directory (here is an example for the Cubietruck board). The slow failsafe DRAM settings for an A10/A13/A20 device may look like:

+S:CONFIG_DRAM_CLK=360
+S:CONFIG_DRAM_ZQ=123
+S:CONFIG_DRAM_EMR1=4
+S:CONFIG_DRAM_TIMINGS_DDR3_800E_1066G_1333J=y

A more complete set of available Kconfig options and their descriptions can be found here: http://git.denx.de/?p=u-boot.git;a=blob;f=board/sunxi/Kconfig;h=e1d4ab148f0838d746889775cfbab5bed57838bf;hb=a705ebc81b7f91bbd0ef7c634284208342901149#l177

The settings from the Android firmware

Somewhat better settings can be retrieved by the meminfo tool from the stock Android or GNU/Linux system, provided by the device manufacturer. It still makes sense to test the reliability of the resulting DRAM configuration. Because some vendors are providing poor configuration for ZQ or EMR1, but nevertheless trying to optimistically set the DRAM clock speed too high.

Performance optimized DRAM settings

Tuning DRAM setting for each individual board can provide much better performance than the failsafe defaults. This involves trial and error testing of different settings using a tool until an optimal combination is found. The DRAM Controller page provides links to start researching this topic. This approach will be time consuming, so a satisfactory solution using one of the other approaches may be best to start with.

See also

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