NixOS on ARM/Raspberry Pi 4

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Raspberry Pi 4 Family
Manufacturer	Raspberry Pi Foundation
Architecture	AArch64
Bootloader	Custom or U-Boot
Boot order	Configurable; SD, USB, Netboot
Maintainer
Raspberry Pi 4B
SoC	BCM2711

Raspberry Pi系列设备是由Raspberry Pi基金会制造的一系列单板计算机。它们都基于Broadcom片上系统（SoC）。

状态

Raspberry Pi 4家族仅支持AArch64。社区支持使用armv7。

Board-specific 安装说明

首先按照 generic installation steps 获取安装程序映像，并使用 installation and configuration steps.

Raspberry Pi 4B可与 generic SD image配合使用.

nix.dev上提供了在Raspberry Pi上安装NixOS的示例说明。installing NixOS on a Raspberry Pi

Warning: 请注意，Raspberry Pi 4有两个HDMI输出，显然有时控制台/TTY的用户提示显示在HDMI 1上，而启动过程显示在HDMI 0上（官方（非NixOs）非图形精简版图像也可能出现这种情况）。因此，如果在第2阶段结束时收到“欢迎使用NixOs”的消息后，您的屏幕变黑/断开连接，请尝试使用另一个HDMI端口。请在此处查看相关错误。 Note that the Raspberry Pi 4 has two HDMI outputs, and apparently sometimes the user prompt for the console/TTY is displayed on HDMI 1 while the boot process is displayed on HDMI 0 (this may even be the case with the official (non NixOs) non-graphical lite image). So if after the message "Welcome on NixOs" at the end of phase 2 your screen goes black/disconnects, try to use the other HDMI port. See the related bug here.

配置

使用nixos-generate-config将生成所需的最小配置。

Raspberry Pi 4在现代内核上得到了很好的支持。但是，如果您遇到GPU支持或其他deviceTree怪癖的问题，您可能希望添加nixos硬件通道：Raspberry Pi 4 is well-supported on modern kernels. However, if you encounter issues with GPU support or other deviceTree quirks, you may wish to add the nixos-hardware channel:

nix-channel --add https://github.com/NixOS/nixos-hardware/archive/master.tar.gz nixos-hardware

nix-channel --update

/etc/nixos/configuration.nix

{ config, pkgs, lib, ... }:
{
  imports =
    [
      <nixos-hardware/raspberry-pi/4>
      ./hardware-configuration.nix
    ];
  hardware = {
    raspberry-pi."4".apply-overlays-dtmerge.enable = true;
    deviceTree = {
      enable = true;
      filter = "*rpi-4-*.dtb";
    };
  };
  console.enable = false;
  environment.systemPackages = with pkgs; [
    libraspberrypi
    raspberrypi-eeprom
  ];
  system.stateVersion = "24.11";
}

USB boot

For USB booting to work properly, a firmware update might be needed:

 $ nix-shell -p raspberrypi-eeprom
 $ rpi-eeprom-update -d -a

Now reboot the device so it can update the firmware from the boot partition.

GPU支持

以下配置示例是基于将其添加到已工作的配置中的假设而构建的。它们不是完整的配置。The following configuration samples are built on the assumption that they are added to an already working configuration. They are not complete configurations.

Without GPU

/etc/nixos/configuration.nix

{
  services.xserver = {
    enable = true;
    displayManager.lightdm.enable = true;
    desktopManager.gnome.enable = true;
    videoDrivers = [ "fbdev" ];
  };
}

With GPU

In nixos-hardware#261 an option has been added to use the fkms-3d (modesetting) overlay which uses the V3D renderer. This will only work with the vendor kernel, which is the default in NixOS.

/etc/nixos/configuration.nix

{ pkgs, ... }:

{
  imports = [
    .../nixos-hardware/raspberry-pi/4
  ];

  hardware.raspberry-pi."4".fkms-3d.enable = true;

  services.xserver = {
    enable = true;
    displayManager.lightdm.enable = true;
    desktopManager.gnome.enable = true;
  };
}

Tools

The raspberry tools are available in the libraspberrypi package and include commands like vcgencmd to measure temperature and CPU frequency.

Audio

In addition to the usual config, you will need to enable hardware audio support:

/etc/nixos/configuration.nix

{
  # Enable audio devices
  boot.kernelParams = [ "snd_bcm2835.enable_hdmi=1" "snd_bcm2835.enable_headphones=1" ];
  boot.loader.raspberryPi.firmwareConfig = ''
    dtparam=audio=on
  '';
}

If you're running headless, you can also disable HDMI audio and force use of the headphones jack by adding hdmi_ignore_edid_audio=1 on a line below dtparam=audio=on.

网络配置

以太网和wifi接口应该开箱即用。除了正常的网络配置外，如果您在启动后不久遇到速度慢或主机在网络上无法访问的问题，请考虑禁用wifi省电。对于NetworkManager，以下配置就足够了：Ethernet and wifi interfaces should work out of the box. In addition to normal network configuration, consider disabling wifi powersaving if you experience slowness or issues with the host becoming unreachable on the network shortly after boot. For NetworkManager, the following configuration is sufficient:

/etc/nixos/configuration.nix

{
  # Basic networking
  networking.networkmanager.enable = true;
  # Prevent host becoming unreachable on wifi after some time.
  networking.networkmanager.wifi.powersave = false;
}

Using GPIO pins as non-root

By default, the GPIO pins are enabled, but can only be accessed by the root user. This can be addressed by adding a udev rule to your configuration that changes the ownership of /dev/gpiomem and the other required devices.

The following code adds a group gpio and adds the user mygpiouser to that group. You probably want to put your own user name here.

The extraRules changes the owner of gpiomem and all other files needed for GPIO to work to root:gpio and changes the permissions to 0660. Therefore, the root user and anyone in the gpio group can now access the GPIO pins.

  # Create gpio group
  users.groups.gpio = {};

  # Change permissions gpio devices
  services.udev.extraRules = ''
    SUBSYSTEM=="bcm2835-gpiomem", KERNEL=="gpiomem", GROUP="gpio",MODE="0660"
    SUBSYSTEM=="gpio", KERNEL=="gpiochip*", ACTION=="add", RUN+="${pkgs.bash}/bin/bash -c 'chown root:gpio /sys/class/gpio/export /sys/class/gpio/unexport ; chmod 220 /sys/class/gpio/export /sys/class/gpio/unexport'"
    SUBSYSTEM=="gpio", KERNEL=="gpio*", ACTION=="add",RUN+="${pkgs.bash}/bin/bash -c 'chown root:gpio /sys%p/active_low /sys%p/direction /sys%p/edge /sys%p/value ; chmod 660 /sys%p/active_low /sys%p/direction /sys%p/edge /sys%p/value'"
  '';

  # Add user to group
  users = {
    users.mygpiouser = {
      extraGroups = [ "gpio" ... ];
      ....
    };
  };

Enabling the SPI

To enable the SPI, you would normally add dtparam=spi=on to /boot/config.txt. This is not possible on NixOS, and instead you have to apply a device tree overlay. For this we use the hardware.deviceTree.overlays option. After applying the overlay, we add an spi group and change the owner of the spidev device to it, similarly to GPIO.

hardware.raspberry-pi."4".apply-overlays-dtmerge.enable = true;
hardware.deviceTree = {
  enable = true;
  filter = "*-rpi-*.dtb";
  overlays = [
    {
      name = "spi";
      dtboFile = ./spi0-0cs.dtbo;
    }
  ];
};

users.groups.spi = {};

services.udev.extraRules = ''
  SUBSYSTEM=="spidev", KERNEL=="spidev0.0", GROUP="spi", MODE="0660"
'';

The the spi0-0cd.dtso file can be downloaded here. You might have to change the compatible field to "raspberrypi" in the dtbo file.

HDMI-CEC

A few bits and pieces for using HDMI-CEC on the Pi4:

/etc/nixos/configuration.nix

{ pkgs, ... }:

{
  # an overlay to enable raspberrypi support in libcec, and thus cec-client
  nixpkgs.overlays = [
    # nixos-22.05
    # (self: super: { libcec = super.libcec.override { inherit (self) libraspberrypi; }; })
    # nixos-22.11
    (self: super: { libcec = super.libcec.override { withLibraspberrypi = true; }; })
  ];

  # install libcec, which includes cec-client (requires root or "video" group, see udev rule below)
  # scan for devices: `echo 'scan' | cec-client -s -d 1`
  # set pi as active source: `echo 'as' | cec-client -s -d 1`
  environment.systemPackages = with pkgs; [
    libcec
  ];

  services.udev.extraRules = ''
    # allow access to raspi cec device for video group (and optionally register it as a systemd device, used below)
    KERNEL=="vchiq", GROUP="video", MODE="0660", TAG+="systemd", ENV{SYSTEMD_ALIAS}="/dev/vchiq"
  '';

  # optional: attach a persisted cec-client to `/run/cec.fifo`, to avoid the CEC ~1s startup delay per command
  # scan for devices: `echo 'scan' > /run/cec.fifo ; journalctl -u cec-client.service`
  # set pi as active source: `echo 'as' > /run/cec.fifo`
  systemd.sockets."cec-client" = {
    after = [ "dev-vchiq.device" ];
    bindsTo = [ "dev-vchiq.device" ];
    wantedBy = [ "sockets.target" ];
    socketConfig = {
      ListenFIFO = "/run/cec.fifo";
      SocketGroup = "video";
      SocketMode = "0660";
    };
  };
  systemd.services."cec-client" = {
    after = [ "dev-vchiq.device" ];
    bindsTo = [ "dev-vchiq.device" ];
    wantedBy = [ "multi-user.target" ];
    serviceConfig = {
      ExecStart = ''${pkgs.libcec}/bin/cec-client -d 1'';
      ExecStop = ''/bin/sh -c "echo q > /run/cec.fifo"'';
      StandardInput = "socket";
      StandardOutput = "journal";
      Restart="no";
  };
}

Enabling Bluetooth

One might get bluetooth to work with this in the configuration file:

/etc/nixos/configuration.nix

  systemd.services.btattach = {
    before = [ "bluetooth.service" ];
    after = [ "dev-ttyAMA0.device" ];
    wantedBy = [ "multi-user.target" ];
    serviceConfig = {
      ExecStart = "${pkgs.bluez}/bin/btattach -B /dev/ttyAMA0 -P bcm -S 3000000";
    };
  };

Customizing & Generating SD image without installation step

There's a nix-community project to support fine-grained kernel & config.txt, and generate the image directly:

nix-community/raspberry-pi-nix

Notes about the boot process

Unless using an extremely early WIP image, the Raspberry Pi 4B boots using the U-Boot platform firmware.

Updating U-Boot/Firmware

 
$ nix-shell -p raspberrypi-eeprom
$ sudo mount /dev/disk/by-label/FIRMWARE /mnt
$ sudo BOOTFS=/mnt FIRMWARE_RELEASE_STATUS=stable rpi-eeprom-update -d -a

source

Troubleshooting

Audio not playing and Bluetooth: no controller available

On the Raspberry Pi kernel, the jack may never play audio, and no Bluetooth devices may ever be found. To get this to work, it is recommended to switch to the mainline kernel. See nixpkgs#123725 for more info.

Touch screen not working

You have to declare this in your configuration.nix:

hardware.raspberry-pi."4" = {
  touch-ft5406.enable = true;
};