modules/zyxel-dual-image: init

This adds a simple boot blessing module, to be used, with the Zyxel NWA50AX.

There's a lot of elephant in the rooms: how do you upgrade kernel, etc.

Signed-off-by: Raito Bezarius <masterancpp@gmail.com>

modules/zyxel-dual-image/service.nix

@@ -0,0 +1,33 @@
+{
+  liminix
+, lib
+, zyxel-bootconfig
+}:
+{ ensureActiveImage, primaryMtdPartition, secondaryMtdPartition, bootConfigurationMtdPartition, kernelCommandLineSource }:
+let
+  inherit (liminix.services) oneshot;
+  activeImageIndex = if ensureActiveImage == "primary" then 0 else 1;
+in oneshot {
+  name = "zyxel-boot-configure";
+  up = ''
+    set -- $(cat /proc/device-tree/chosen/bootargs)
+    for x in "$@"; do
+        case "$x" in
+            bootImage=*)
+            BOOT_IMAGE="''${x#bootImage=}"
+            echo "Current boot image is $BOOT_IMAGE."
+            ;;
+        esac
+    done
+
+    if test -z "$BOOT_IMAGE"; then
+      echo "No valid image was provided in the kernel command line."
+      exit 1
+    else
+      ${lib.getExe zyxel-bootconfig} ${bootConfigurationMtdPartition} set-image-status "$BOOT_IMAGE" valid
+      ${lib.getExe zyxel-bootconfig} ${bootConfigurationMtdPartition} set-active-image ${toString activeImageIndex}
+
+      echo "Active image is now ${ensureActiveImage}"
+    fi
+  '';
+}