NixOS on ARM/PINE A64-LTS

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PINE A64-LTS
Manufacturer	PINE64 (Pine Microsystems Inc.)
Architecture	AArch64
Bootloader	Upstream U-Boot
Boot order	SD, eMMC, SPI NOR Flash
Maintainer	samueldr

Note: While made by the same manufacturer and using an Allwinner SOC, the PINE A64 (non LTS) does not use the same bootloader.

The PINE A64-LTS is an affordable "Long Time Supply" single board computer built around the Allwinner R18 SOC.

It can boot from SD or from an eMMC.

The SOPINE board from the same manufacturer, using the Baseboard "Model A" should be 100% compatible with the A64-LTS; the A64-LTS support is built using the device tree of the Baseboard "Model A". Though untested, this should mean that the Baseboard "Model A" will work with NixOS^{[testing needed]}.

Status

Upstream NixOS AArch64 image boots on the PINE A64-LTS, using the proper upstream U-Boot.

U-boot support has been added 2018-03-18. The bootloader with SPL can be downloaded from these location:

• sopine-u-boot-sunxi-with-spl.bin built by Dezgeg.
• Trunk builds on hydra.

Board-specific installation notes

First follow the generic installation steps to get the installer image on an SD card or the eMMC. A compatible eMMC to SD may be required to flash the eMMC. If you do not have one available, it is possible to boot another operating system on the A64-LTS and from there dd to the eMMC.

U-Boot needs to be copied to specific sectors on the microSD card with dd. Download U-Boot for the board (sopine-u-boot-sunxi-with-spl.bin), and copy it to the correct location with (again, replace /dev/sdX with the correct path to the SD card device):

sudo dd if=sopine-u-boot-sunxi-with-spl.bin of=/dev/sdX bs=1024 seek=8

Then, install using the installation and configuration steps.

Serial console

Follows a simplified drawing of the edge of the Pine A64-LTS, with two locations to tap for serial.

EXP Connector
Pin	Function
7	UART0_TX
8	UART0_RX
9	GND
Euler "e" Connector
Pin	Function
29	UART0_TX
30	UART0_RX
33	GND

Compatibility notes

Mainline kernel
Ethernet	Up to and including 4.19, ethernet seems to have troubles. The interface is detected but does not work right. Verified only starting with 4.20 (rc4 tested), ethernet seems to work sometimes. It may fail with dmesg messages like dwmac-sun8i 1c30000.ethernet eth0: Could not attach to PHY and dwmac-sun8i 1c30000.ethernet eth0: stmmac_open: Cannot attach to PHY (error: -19).
HDMI	Starting with 4.20 (rc4 tested), HDMI output works. Up to and including 4.19, HDMI output does not work.

Downstream kernel

Using a kernel based on the downstream patches, it is possible to get both Ethernet and HDMI working.

• CallMeFoxie/linux@v4.14-pine64
• Pine64 Forum post by CallMeFoxie

Note: Keep in mind that using non-upstream forks of the kernel always incurs some risk as far as security goes.

Follows an example derivation and overlay to build the known working fork.

# linux-pine64.nix
{ fetchFromGitHub, buildLinux, ... } @ args:
buildLinux (args // rec {
  version = "4.14.23";
  modDirVersion = "4.14.23";
  extraMeta.branch = "4.14";
  src = fetchFromGitHub {
    owner = "CallMeFoxie";
    repo = "linux";
    rev = "f0899693d21e15ce32df4d4702f236dfe3e0eba7";
    sha256 = "043q7v7c5w84dnbgsmz117q712ljqrgay5707pz4vnvxl53czk4h";
  };
  extraMeta.platforms = [ "aarch64-linux" ];
  structuredExtraConfig = {
    # Options for HDMI.
    # Fixes this:
    #   sun4i-drm display-engine: master bind failed: -517
    SUN8I_DE2_CCU = "y";
  };
} // (args.argsOverride or {}))

# overlay.nix
self: super:

let
  inherit (super) callPackage kernelPatches;
in
{
  linux_pine64_4_14 = callPackage ./linux-pine64.nix {
    kernelPatches = [
      kernelPatches.bridge_stp_helper
      kernelPatches.modinst_arg_list_too_long
    ];
  };
  linuxPackages_pine64_4_14 = self.linuxPackagesFor self.linux_pine64_4_14;
}

SPI NOR flash

The Pine A64-LTS is equipe with a 4MB SPI NOR flash chip. The CPU will read the bootloader from it, after trying the SD card and the eMMC.

Flashing U-Boot to the SPI NOR flash will allow booting the sd-image-aarch64.img based images without further manipulating the image or the boot device (e.g. without embedding U-Boot to the usb drive). It may also allow booting UEFI compliant AArch64 images, though this is unverified.

The author did not find ways to flash the NOR flash from a running Linux system using the mainline kernel.

Flashing from FEL

The easiest method to trigger FEL mode is to not have previously flashed the SPI NOR flash with a valid bootloader, and to remove all storage devices used to boot. The Pine A64-LTS will fallback to FEL mode.

To connect the Pine A64-LTS to the computer in FEL mode, you will need a USB A-to-A (male to male) cable, and plug to the upper USB port.

Once started in FEL mode, the computer should see the following device.

Bus ___ Device ___: ID 1f3a:efe8 Onda (unverified) V972 tablet in flashing mode

It is, then, possible to use sunxi-fel from sunxi-tools to flash the a bootloader to the SPI NOR flash.

Note: As of 2018-11-24, the sunxi-tools package is not up-to-date enough, and does not have the required spiflash-write sub-command. See #51007.

$ nix-shell -p sunxi-tools
[nix-shell:~]$ sudo sunxi-fel -l
USB device ___:___   Allwinner A64     ________:________:________:________
[nix-shell:~]$ sudo sunxi-fel -p spiflash-write 0 u-boot-sunxi-with-spl.bin
100% [================================================]   575 kB,   96.9 kB/s

Once complete, unplug the power from the Pine A64-LTS, unplug the Pine A64-LTS from the host computer, and try booting without storage devices, but either serial or HDMI. When successful, U-Boot will start, and eventually try to network boot.

Note: Once a valid bootloader is on the SPI NOR flash, FEL mode will not be entered automatically. Follow instructions of the FEL page of the linux-sunxi wiki for alternative ways to enter FEL mode.

Flashing from U-Boot

It is possible, through using a U-Boot bootloader built from the u-boot-sunxi tree, to write to the SPI NOR flash. The ayufan-pine64/bootloader-build has such a build. Using the released .img files, it is possible to write their custom build or erase their custom build. From their custom build, it is possible to write to the SPI NOR flash using the sf command.

# Detect the SPI NOR flash
=> sf probe
SF: Detected w25q128bv with page size 256 Bytes, erase size 4 KiB, total 16 MiB
# Sanity checks
=> ls mmc 0:1
   558296   u-boot.bin
1 file(s), 0 dir(s)
# Loading the bootloader from an SD card
=> load mmc 0:1 ${kernel_addr_r} /u-boot.bin
reading /u-boot.bin
558296 bytes read in 79 ms (6.7 MiB/s)
# Erasing the SPI NOR flash
=> sf erase 0 3e8000
SF: 4096000 bytes @ 0x0 Erased: OK
# Writing to the SPI NOR flash
=> sf write ${kernel_addr_r} 0 3e8000
device 0 offset 0x0, size 0x3e8000
SF: 4096000 bytes @ 0x0 Written: OK

Resources

• Official product page
• linux-sunxi wiki page