NixOS on ARM/ODROID-C2

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Hardkernel ODROID-C2
Manufacturer	Hardkernel
Architecture	AArch64
Bootloader	Upstream U-Boot
Boot options	SD, eMMC

Status

ODROID-C2 support is being worked on by @grahamc. Mainline kernel from NixOS has been reported as working. A non-specified build from mainline u-boot also has been reported to work.

Board-specific installation notes

Note this assumes u-boot is in partition 1 of your board's connected eMMC. If you haven't done that yet, you can build it with nix and then write it this fusing script (using an emmc/usb adapter) [1] (replace /dev/sdX with the device for the eMMC):

nix-build '<nixpkgs>' -A pkgsCross.aarch64-multiplatform.ubootOdroidC2
cd result
bash /path/to/sd_fusing.sh /dev/sdX

1. Download the sd-image from Hydra at https://hydra.nixos.org/job/nixos/release-18.09-aarch64/nixos.sd_image.aarch64-linux/latest
2. Copy it to the SD card
3. Mount first partition to /mnt with sudo mount /dev/mmcblk0p1 /mnt
4. Edit /mnt/extlinux/extlinux.conf and delete all the console=tty.... arguments in the APPEND line
5. Add console=ttyAML0,115200n8 to the end of the APPEND line

it will look something like this:

$ cat  /mnt/extlinux/extlinux.conf
# Generated file, all changes will be lost on nixos-rebuild!

# Change this to e.g. nixos-42 to temporarily boot to an older configuration.
DEFAULT nixos-default

MENU TITLE ------------------------------------------------------------
TIMEOUT 30

LABEL nixos-default
  MENU LABEL NixOS - Default
  LINUX ../nixos/gz1chw67hj8fj2b3xdrkv1nxrv8jvdzv-linux-4.19.13-Image
  INITRD ../nixos/4gifkl2yv2g58nxmf6z68y42s70xrsg0-initrd-initrd
  FDTDIR ../nixos/gz1chw67hj8fj2b3xdrkv1nxrv8jvdzv-linux-4.19.13-dtbs
  APPEND systemConfig=/nix/store/...-nixos-system-nixos-xxx.xxx.xxx.xxx init=/nix/store/...-nixos-system-nixos-xx.xx.xxxx.xxx init loglevel=7 cma=32M console=ttyAML0,115200n8

and then boot the sdcard.

Once booted, partition your on-board emmc like:

Device         Boot    Start      End  Sectors  Size Id Type
/dev/mmcblk0p1          2048   264191   262144  128M  c W95 FAT32 (LBA)
/dev/mmcblk0p2 *      264192 50595839 50331648   24G 83 Linux
/dev/mmcblk0p3      50595840 61071359 10475520    5G 83 Linux

note **p2** is bootable.

$ mkfs.ext4 /dev/mmcblk0p2
$ mkswap /dev/mmcblk0p3
$ swapon /dev/mmcblk0p3
$ mount /dev/mmcblk0p2 /mnt
$ nixos-generate-config /mnt
$ nixos-install
$ reboot

Serial console

I used minicom to access the serial:

$ cat /etc/minirc.odroid-c2 
# Machine-generated file - use "minicom -s" to change parameters.
pu port             /dev/ttyUSB0
pu lock             /var/lock
pu rtscts           No

then run sudo minicom to access the serial console.

---

Xorg

Nixos 20.03 should install all modules needed for this to work but at least two changes should be made to the xorg configuration:

services.xserver.videoDrivers = [ "modesetting"  ];
  services.xserver.extraConfig = ''
    Section "OutputClass"
        Identifier "Meson"
        MatchDriver "meson"
        Driver "modesetting"
        Option "PrimaryGPU" "true"
    EndSection
  '';

The HW cursor support was very laggy when tried on 20.03 so enabling the software cursor may be desired:

services.xserver.deviceSection = "Option \"SWcursor\" \"on\"";

Resources

• Official product page
• NixOS Image Build for Odroid-C2 by George Whewell