[PATCH] templates: allow loading a Device Tree file from user conf

[Matteo Croce]

From: Matteo Croce <mcroce@microsoft.com>

Some machines rely on Device Tree for hardware discovery, so a
.dtb file must be passed to the kernel.

GRUB can do this via the `devicetree` command, but it's not possible
to do this from the user configuration.

Add a GRUB_DEVICETREE_FILE variable which holds the path of the .dtb
file relative to the boot partition and, if present, adds the
devicetree command to the menuentry.

Signed-off-by: Matteo Croce <mcroce@microsoft.com>
---
 util/grub-mkconfig.in   | 1 +
 util/grub.d/10_linux.in | 5 +++++
 2 files changed, 6 insertions(+)

diff --git a/util/grub-mkconfig.in b/util/grub-mkconfig.in
index d3e879b8e..3e15e6f20 100644
--- a/util/grub-mkconfig.in
+++ b/util/grub-mkconfig.in
@@ -228,6 +228,7 @@ export GRUB_DEFAULT \
   GRUB_CMDLINE_NETBSD \
   GRUB_CMDLINE_NETBSD_DEFAULT \
   GRUB_CMDLINE_GNUMACH \
+  GRUB_DEVICETREE_FILE \
   GRUB_EARLY_INITRD_LINUX_CUSTOM \
   GRUB_EARLY_INITRD_LINUX_STOCK \
   GRUB_TERMINAL_INPUT \
diff --git a/util/grub.d/10_linux.in b/util/grub.d/10_linux.in
index e8b01c0d0..fb1bd30f5 100644
--- a/util/grub.d/10_linux.in
+++ b/util/grub.d/10_linux.in
@@ -143,6 +143,11 @@ linux_entry ()
        echo    '$(echo "$message" | grub_quote)'
        linux   ${rel_dirname}/${basename} 
root=${linux_root_device_thisversion} ro ${args}
 EOF
+  if [ -n "${GRUB_DEVICETREE_FILE}" ] && test -e 
"${dirname}/${GRUB_DEVICETREE_FILE}"; then
+    sed "s/^/$submenu_indentation/" << EOF
+       devicetree ${rel_dirname}/${GRUB_DEVICETREE_FILE}
+EOF
+  fi
   if test -n "${initrd}" ; then
     # TRANSLATORS: ramdisk isn't identifier. Should be translated.
     message="$(gettext_printf "Loading initial ramdisk ...")"
-- 
2.28.0