From 37c0b6a0916c31a5eae0a9ddfcc5d0b8fb4569c6 Mon Sep 17 00:00:00 2001
From: David Gibson <david@gibson.dropbear.id.au>
Date: Wed, 10 Nov 2010 09:51:09 +1100
Subject: dtc: Add code to make diffing trees easier

This patch adds a "dtdiff" script to do a useful form diff of two
device trees.  This automatically converts the tree to dts form (if
it's not already) and uses a new "-s" option in dtc to "sort" the
tree.  That is, it sorts the reserve entries, it sorts the properties
within each node by name, and it sorts nodes by name within their
parent.

This gives a pretty sensible diff between the trees, which will ignore
semantically null internal rearrangements (directly diffing the dts
files can give a lot of noise due to the order changes).

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
---
 dtdiff | 38 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 38 insertions(+)
 create mode 100644 dtdiff

(limited to 'dtdiff')

diff --git a/dtdiff b/dtdiff
new file mode 100644
index 0000000..5fa772b
--- /dev/null
+++ b/dtdiff
@@ -0,0 +1,38 @@
+#! /bin/bash
+
+# This script uses the bash <(...) extension.
+# If you want to change this to work with a generic /bin/sh, make sure
+# you fix that.
+
+
+DTC=dtc
+
+source_and_sort () {
+    DT="$1"
+    if [ -d "$DT" ]; then
+	IFORMAT=fs
+    elif [ -f "$DT" ]; then
+	case "$DT" in
+	    *.dts)
+		IFORMAT=dts
+		;;
+	    *.dtb)
+		IFORMAT=dtb
+		;;
+	esac
+    fi
+
+    if [ -z "$IFORMAT" ]; then
+	echo "Unrecognized format for $DT" >&2
+	exit 2
+    fi
+
+    $DTC -I $IFORMAT -O dts -qq -f -s -o - "$DT"
+}
+
+if [ $# != 2 ]; then
+    echo "Usage: dtdiff <device tree> <device tree>" >&2
+    exit 1
+fi
+
+diff -u <(source_and_sort "$1") <(source_and_sort "$2")
-- 
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