From 387f3b58d2cfe131700a3c40541665c1dfde1bbb Mon Sep 17 00:00:00 2001
From: Florian Klink <flokli@flokli.de>
Date: Sun, 21 Jun 2020 10:33:09 +0200
Subject: [PATCH] hardware.deviceTree: add name

This can be used to explicitly specify a specific dtb file, relative to
the dtb base.

Update the generic-extlinux-compatible module to make use of this option.
---
 nixos/modules/hardware/device-tree.nix                | 11 +++++++++++
 .../loader/generic-extlinux-compatible/default.nix    |  3 ++-
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/nixos/modules/hardware/device-tree.nix b/nixos/modules/hardware/device-tree.nix
index 6ae638f17cc9..b3f1dda98c89 100644
--- a/nixos/modules/hardware/device-tree.nix
+++ b/nixos/modules/hardware/device-tree.nix
@@ -27,6 +27,17 @@ in {
           '';
         };
 
+        name = mkOption {
+          default = null;
+          example = "some-dtb.dtb";
+          type = types.nullOr types.str;
+          description = ''
+            The name of an explicit dtb to be loaded, relative to the dtb base.
+            Useful in extlinux scenarios if the bootloader doesn't pick the
+            right .dtb file from FDTDIR.
+          '';
+        };
+
         overlays = mkOption {
           default = [];
           example = literalExample
diff --git a/nixos/modules/system/boot/loader/generic-extlinux-compatible/default.nix b/nixos/modules/system/boot/loader/generic-extlinux-compatible/default.nix
index 5ddf96f57909..416f8aeb1d38 100644
--- a/nixos/modules/system/boot/loader/generic-extlinux-compatible/default.nix
+++ b/nixos/modules/system/boot/loader/generic-extlinux-compatible/default.nix
@@ -4,6 +4,7 @@ with lib;
 
 let
   blCfg = config.boot.loader;
+  dtCfg = config.hardware.deviceTree;
   cfg = blCfg.generic-extlinux-compatible;
 
   timeoutStr = if blCfg.timeout == null then "-1" else toString blCfg.timeout;
@@ -53,7 +54,7 @@ in
   };
 
   config = let
-    builderArgs = "-g ${toString cfg.configurationLimit} -t ${timeoutStr}";
+    builderArgs = "-g ${toString cfg.configurationLimit} -t ${timeoutStr}" + lib.optionalString (dtCfg.name != null) " -n ${dtCfg.name}";
   in
     mkIf cfg.enable {
       system.build.installBootLoader = "${builder} ${builderArgs} -c";