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>

1 files changed, 10 insertions, 2 deletions

diff --git a/dtc.c b/dtc.c
index 8b31d20..cbc0193 100644
--- a/dtc.c
+++ b/dtc.c
@@ -81,6 +81,8 @@ static void  __attribute__ ((noreturn)) usage(void)
 	fprintf(stderr, "\t\tSet the physical boot cpu\n");
 	fprintf(stderr, "\t-f\n");
 	fprintf(stderr, "\t\tForce - try to produce output even if the input tree has errors\n");
+	fprintf(stderr, "\t-s\n");
+	fprintf(stderr, "\t\tSort nodes and properties before outputting (only useful for\n\t\tcomparing trees)\n");
 	fprintf(stderr, "\t-v\n");
 	fprintf(stderr, "\t\tPrint DTC version and exit\n");
 	fprintf(stderr, "\t-H <phandle format>\n");
@@ -97,7 +99,7 @@ int main(int argc, char *argv[])
 	const char *inform = "dts";
 	const char *outform = "dts";
 	const char *outname = "-";
-	int force = 0, check = 0;
+	int force = 0, check = 0, sort = 0;
 	const char *arg;
 	int opt;
 	FILE *outf = NULL;
@@ -109,7 +111,7 @@ int main(int argc, char *argv[])
 	minsize    = 0;
 	padsize    = 0;
 
-	while ((opt = getopt(argc, argv, "hI:O:o:V:R:S:p:fcqb:vH:")) != EOF) {
+	while ((opt = getopt(argc, argv, "hI:O:o:V:R:S:p:fcqb:vH:s")) != EOF) {
 		switch (opt) {
 		case 'I':
 			inform = optarg;
@@ -159,6 +161,10 @@ int main(int argc, char *argv[])
 				    optarg);
 			break;
 
+		case 's':
+			sort = 1;
+			break;
+
 		case 'h':
 		default:
 			usage();
@@ -197,6 +203,8 @@ int main(int argc, char *argv[])
 	fill_fullpaths(bi->dt, "");
 	process_checks(force, bi);
 
+	if (sort)
+		sort_tree(bi);
 
 	if (streq(outname, "-")) {
 		outf = stdout;