raspberry-pi-nix/rpi/default.nix

{ overlay }:
{ lib, pkgs, config, ... }:

{
  imports = [ ../sd-image ./config.nix ./i2c.nix ];

  systemd.services = {
    "raspberry-pi-firmware-migrate" = {
      description = "update the firmware partition";
      wantedBy = [ "multi-user.target" ];
      serviceConfig = let firmware-path = "/boot/firmware";
      in {
        Type = "oneshot";
        MountImages =
          "/dev/disk/by-label/${config.sdImage.firmwarePartitionName}:${firmware-path}";
        StateDirectory = "raspberrypi-firmware";
        ExecStart = pkgs.writeShellScript "migrate-rpi-firmware" ''
          shopt -s nullglob

          TARGET_FIRMWARE_DIR="${firmware-path}"
          TARGET_OVERLAYS_DIR="$TARGET_FIRMWARE_DIR/overlays"
          TMPFILE="$TARGET_FIRMWARE_DIR/tmp"
          UBOOT="${pkgs.uboot_rpi_arm64}/u-boot.bin"
          SRC_FIRMWARE_DIR="${pkgs.raspberrypifw}/share/raspberrypi/boot"
          STARTFILES=("$SRC_FIRMWARE_DIR"/start*.elf)
          DTBS=("$SRC_FIRMWARE_DIR"/*.dtb)
          BOOTCODE="$SRC_FIRMWARE_DIR/bootcode.bin"
          FIXUPS=("$SRC_FIRMWARE_DIR"/fixup*.dat)
          SRC_OVERLAYS_DIR="$SRC_FIRMWARE_DIR/overlays"
          SRC_OVERLAYS=("$SRC_OVERLAYS_DIR"/*)
          CONFIG="${config.hardware.raspberry-pi.config-output}"

          migrate_uboot() {
            echo "migrating uboot"
            touch "$STATE_DIRECTORY/uboot-migration-in-progress"
            cp "$UBOOT" "$TMPFILE"
            mv -T "$TMPFILE" "$TARGET_FIRMWARE_DIR/u-boot-rpi-arm64.bin"
            echo "${
              builtins.toString pkgs.uboot_rpi_arm64
            }" > "$STATE_DIRECTORY/uboot-version"
            rm "$STATE_DIRECTORY/uboot-migration-in-progress"
          }

          migrate_config() {
            echo "migrating config.txt"
            touch "$STATE_DIRECTORY/config-migration-in-progress"
            cp "$CONFIG" "$TMPFILE"
            mv -T "$TMPFILE" "$TARGET_FIRMWARE_DIR/config.txt"
            echo "${config.hardware.raspberry-pi.config-output}" > "$STATE_DIRECTORY/config-version"
            rm "$STATE_DIRECTORY/config-migration-in-progress"
          }

          migrate_firmware() {
            echo "migrating raspberrypi firmware"
            touch "$STATE_DIRECTORY/firmware-migration-in-progress"
            for SRC in "''${STARTFILES[@]}" "''${DTBS[@]}" "$BOOTCODE" "''${FIXUPS[@]}"
            do
              cp "$SRC" "$TMPFILE"
              mv -T "$TMPFILE" "$TARGET_FIRMWARE_DIR/$(basename "$SRC")"
            done

            if [[ ! -d "$TARGET_OVERLAYS_DIR" ]]; then
              mkdir "$TARGET_OVERLAYS_DIR"
            fi

            for SRC in "''${SRC_OVERLAYS[@]}"
            do
              cp "$SRC" "$TMPFILE"
              mv -T "$TMPFILE" "$TARGET_OVERLAYS_DIR/$(basename "$SRC")"
            done
            echo "${
              builtins.toString pkgs.raspberrypifw
            }" > "$STATE_DIRECTORY/firmware-version"
            rm "$STATE_DIRECTORY/firmware-migration-in-progress"
          }

          if [[ -f "$STATE_DIRECTORY/uboot-migration-in-progress" || ! -f "$STATE_DIRECTORY/uboot-version" || $(< "$STATE_DIRECTORY/uboot-version") != ${
            builtins.toString pkgs.uboot_rpi_arm64
          } ]]; then
            migrate_uboot
          fi

          if [[ -f "$STATE_DIRECTORY/config-migration-in-progress" || ! -f "$STATE_DIRECTORY/config-version" || $(< "$STATE_DIRECTORY/config-version") != ${
            builtins.toString config.hardware.raspberry-pi.config-output
          } ]]; then
            migrate_config
          fi

          if [[ -f "$STATE_DIRECTORY/firmware-migration-in-progress" || ! -f "$STATE_DIRECTORY/firmware-version" || $(< "$STATE_DIRECTORY/firmware-version") != ${
            builtins.toString pkgs.raspberrypifw
          } ]]; then
            migrate_firmware
          fi
        '';
      };
    };
  };

  # Default config.txt on Raspberry Pi OS:
  # https://github.com/RPi-Distro/pi-gen/blob/master/stage1/00-boot-files/files/config.txt
  hardware.raspberry-pi.config = {
    cm4 = {
      options = {
        otg_mode = {
          enable = lib.mkDefault true;
          value = lib.mkDefault true;
        };
      };
    };
    pi4 = {
      options = {
        arm_boost = {
          enable = lib.mkDefault true;
          value = lib.mkDefault true;
        };
      };
    };
    all = {
      options = {
        # The firmware will start our u-boot binary rather than a
        # linux kernel.
        kernel = {
          enable = true;
          value = "u-boot-rpi-arm64.bin";
        };
        arm_64bit = {
          enable = true;
          value = true;
        };
        enable_uart = {
          enable = true;
          value = true;
        };
        avoid_warnings = {
          enable = lib.mkDefault true;
          value = lib.mkDefault true;
        };
        camera_auto_detect = {
          enable = lib.mkDefault true;
          value = lib.mkDefault true;
        };
        display_auto_detect = {
          enable = lib.mkDefault true;
          value = lib.mkDefault true;
        };
        disable_overscan = {
          enable = lib.mkDefault true;
          value = lib.mkDefault true;
        };
      };
      dt-overlays = {
        vc4-kms-v3d = {
          enable = lib.mkDefault true;
          params = { };
        };
      };
    };
  };

  nixpkgs = { overlays = [ overlay ]; };
  boot = {
    initrd.availableKernelModules = [
      "usbhid"
      "usb_storage"
      "vc4"
      "pcie_brcmstb" # required for the pcie bus to work
      "reset-raspberrypi" # required for vl805 firmware to load
    ];
    kernelPackages = pkgs.linuxPackagesFor (pkgs.rpi-kernels.latest.kernel);

    loader = {
      grub.enable = lib.mkDefault false;
      generic-extlinux-compatible = {
        enable = lib.mkDefault true;
        # We want to use the device tree provided by firmware, so don't
        # add FDTDIR to the extlinux conf file.
        useGenerationDeviceTree = false;
      };
    };
  };
  hardware.enableRedistributableFirmware = true;

  services = {
    udev.extraRules = ''
      SUBSYSTEM=="dma_heap", GROUP="video", MODE="0660"
      KERNEL=="gpiomem", GROUP="gpio", MODE="0660"
      KERNEL=="gpiochip*", GROUP="gpio", MODE="0660"
    '';
  };
}