Raspberry Pi profile

This machine profile is used for my three Raspberry Pi 4B machines. These machines were set up using the official NixOS SD card images.

{ config, lib, ... }:
let
  cfg = config.mjm.profiles.raspberry-pi;
in
{
  options.mjm.profiles.raspberry-pi = {
    enable = lib.mkEnableOption "Raspberry Pi hardware support";
  };

  config = lib.mkIf cfg.enable {
    <<config>>
  };
}

nixpkgs.hostPlatform = "aarch64-linux";

Of course, Raspberry Pi is an aarch64 device.

boot.loader.systemd-boot.enable = true;

While I initially provisioned these machines with the NixOS SD card images, which use U-Boot, they now run UEFI firmware and can boot with systemd-boot like everything else.

boot.initrd.systemd.tpm2.enable = false;

Raspberry Pis don't have a TPM. I don't remember at this point what the failure looks like if you leave this enabled, but it did cause problems.

boot.initrd.availableKernelModules = [
  "usbhid"
  "usb_storage"
  "vc4"
  "pcie_brcmstb"
  "reset-raspberrypi"
];

These modules come from the nixos-hardware repo, which I don't use for this because its modules enable their configuration on import rather than gating it behind an option.

hardware.enableRedistributableFirmware = true;

Generally just a good idea to enable redistributable firmware. Little downside, and you like your hardware to work, don't you?