initial mac nixos config

hosts/mac-nixos/apple-silicon-support/modules/default.nix

@@ -0,0 +1,69 @@
+{ config, pkgs, lib, ... }:
+{
+  imports = [
+    ./kernel
+    ./mesa
+    ./peripheral-firmware
+    ./boot-m1n1
+    ./sound
+  ];
+
+  config = let
+      cfg = config.hardware.asahi;
+    in lib.mkIf cfg.enable {
+      nixpkgs.overlays = lib.mkBefore [ cfg.overlay ];
+
+      hardware.asahi.pkgs =
+        if cfg.pkgsSystem != "aarch64-linux"
+        then
+          import (pkgs.path) {
+            crossSystem.system = "aarch64-linux";
+            localSystem.system = cfg.pkgsSystem;
+            overlays = [ cfg.overlay ];
+          }
+        else pkgs;
+    };
+
+  options.hardware.asahi = {
+    enable = lib.mkOption {
+      type = lib.types.bool;
+      default = true;
+      description = ''
+        Enable the basic Asahi Linux components, such as kernel and boot setup.
+      '';
+    };
+
+    pkgsSystem = lib.mkOption {
+      type = lib.types.str;
+      default = "aarch64-linux";
+      description = ''
+        System architecture that should be used to build the major Asahi
+        packages, if not the default aarch64-linux. This allows installing from
+        a cross-built ISO without rebuilding them during installation.
+      '';
+    };
+
+    pkgs = lib.mkOption {
+      type = lib.types.raw;
+      description = ''
+        Package set used to build the major Asahi packages. Defaults to the
+        ambient set if not cross-built, otherwise re-imports the ambient set
+        with the system defined by `hardware.asahi.pkgsSystem`.
+      '';
+    };
+
+    overlay = lib.mkOption {
+      type = lib.mkOptionType {
+        name = "nixpkgs-overlay";
+        description = "nixpkgs overlay";
+        check = lib.isFunction;
+        merge = lib.mergeOneOption;
+      };
+      default = import ../packages/overlay.nix;
+      defaultText = "overlay provided with the module";
+      description = ''
+        The nixpkgs overlay for asahi packages.
+      '';
+    };
+  };
+}