nixpkgs/pkgs/os-specific/linux/device-tree/default.nix

66 lines
2.1 KiB
Nix

{ lib, stdenv, stdenvNoCC, dtc }:
with lib; {
# Compile single Device Tree overlay source
# file (.dts) into its compiled variant (.dtb)
compileDTS = ({
name,
dtsFile,
includePaths ? [],
extraPreprocessorFlags ? []
}: stdenv.mkDerivation {
inherit name;
nativeBuildInputs = [ dtc ];
buildCommand =
let
includeFlagsStr = lib.concatMapStringsSep " " (includePath: "-I${includePath}") includePaths;
extraPreprocessorFlagsStr = lib.concatStringsSep " " extraPreprocessorFlags;
in
''
$CC -E -nostdinc ${includeFlagsStr} -undef -D__DTS__ -x assembler-with-cpp ${extraPreprocessorFlagsStr} ${dtsFile} | \
dtc -I dts -O dtb -@ -o $out
'';
});
applyOverlays = (base: overlays': stdenvNoCC.mkDerivation {
name = "device-tree-overlays";
nativeBuildInputs = [ dtc ];
buildCommand = let
overlays = toList overlays';
in ''
mkdir -p $out
cd "${base}"
find . -type f -name '*.dtb' -print0 \
| xargs -0 cp -v --no-preserve=mode --target-directory "$out" --parents
for dtb in $(find "$out" -type f -name '*.dtb'); do
dtbCompat=$(fdtget -t s "$dtb" / compatible 2>/dev/null || true)
# skip files without `compatible` string
test -z "$dtbCompat" && continue
${flip (concatMapStringsSep "\n") overlays (o: ''
overlayCompat="$(fdtget -t s "${o.dtboFile}" / compatible)"
# skip incompatible and non-matching overlays
if [[ ! "$dtbCompat" =~ "$overlayCompat" ]]; then
echo "Skipping overlay ${o.name}: incompatible with $(basename "$dtb")"
elif ${if (o.filter == null) then "false" else ''
[[ "''${dtb//${o.filter}/}" == "$dtb" ]]
''}
then
echo "Skipping overlay ${o.name}: filter does not match $(basename "$dtb")"
else
echo -n "Applying overlay ${o.name} to $(basename "$dtb")... "
mv "$dtb"{,.in}
fdtoverlay -o "$dtb" -i "$dtb.in" "${o.dtboFile}"
echo "ok"
rm "$dtb.in"
fi
'')}
done
'';
});
}