This make the process of applying overlays more reliable by: 1. Ignoring dtb files that are not really device trees. [^1] 2. Adding a `filter` option (per-overlay, there already is a global one) to limit the files to which the overlay applies. This is useful in cases where the `compatible` string is ambiguous and multiple unrelated files match. Previously the script would fail in both cases. [^1]: For example, there is dtbs/overlays/overlay_map.dtb in the Raspberry Pi 1 kernel.
46 lines
1.4 KiB
Nix
46 lines
1.4 KiB
Nix
{ lib, stdenvNoCC, dtc }:
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with lib; {
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applyOverlays = (base: overlays': stdenvNoCC.mkDerivation {
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name = "device-tree-overlays";
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nativeBuildInputs = [ dtc ];
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buildCommand = let
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overlays = toList overlays';
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in ''
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mkdir -p $out
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cd "${base}"
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find . -type f -name '*.dtb' -print0 \
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| xargs -0 cp -v --no-preserve=mode --target-directory "$out" --parents
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for dtb in $(find "$out" -type f -name '*.dtb'); do
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dtbCompat=$(fdtget -t s "$dtb" / compatible 2>/dev/null || true)
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# skip files without `compatible` string
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test -z "$dtbCompat" && continue
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${flip (concatMapStringsSep "\n") overlays (o: ''
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overlayCompat="$(fdtget -t s "${o.dtboFile}" / compatible)"
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# skip incompatible and non-matching overlays
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if [[ ! "$dtbCompat" =~ "$overlayCompat" ]]; then
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echo -n "Skipping overlay ${o.name}: incompatible with $(basename "$dtb")"
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continue
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fi
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${optionalString (o.filter != null) ''
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if [[ "''${dtb//${o.filter}/}" == "$dtb" ]]; then
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echo -n "Skipping overlay ${o.name}: filter does not match $(basename "$dtb")"
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continue
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fi
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''}
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echo -n "Applying overlay ${o.name} to $(basename "$dtb")... "
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mv "$dtb"{,.in}
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fdtoverlay -o "$dtb" -i "$dtb.in" "${o.dtboFile}"
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echo "ok"
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rm "$dtb.in"
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'')}
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done
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'';
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});
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}
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