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 <[email protected]>

Makefile

@@ -111,6 +111,7 @@ BIN += convert-dtsv0
 BIN += dtc
 BIN += ftdump
 
+SCRIPTS = dtdiff
 
 all: $(BIN) libfdt
 
@@ -155,10 +156,10 @@ endif
 # intermediate target and building them again "for real"
 .SECONDARY: $(DTC_GEN_SRCS) $(CONVERT_GEN_SRCS)
 
-install: all
+install: all $(SCRIPTS)
 	@$(VECHO) INSTALL
 	$(INSTALL) -d $(DESTDIR)$(BINDIR)
-	$(INSTALL) $(BIN) $(DESTDIR)$(BINDIR)
+	$(INSTALL) $(BIN) $(SCRIPTS) $(DESTDIR)$(BINDIR)
 	$(INSTALL) -d $(DESTDIR)$(LIBDIR)
 	$(INSTALL) $(LIBFDT_lib) $(DESTDIR)$(LIBDIR)
 	$(INSTALL) -m 644 $(LIBFDT_archive) $(DESTDIR)$(LIBDIR)

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;

dtc.h

@@ -220,6 +220,7 @@ struct boot_info {
 
 struct boot_info *build_boot_info(struct reserve_info *reservelist,
 				  struct node *tree, uint32_t boot_cpuid_phys);
+void sort_tree(struct boot_info *bi);
 
 /* Checks */
 

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")

livetree.c

@@ -470,3 +470,140 @@ uint32_t guess_boot_cpuid(struct node *tree)
 
 	return propval_cell(reg);
 }
+
+static int cmp_reserve_info(const void *ax, const void *bx)
+{
+	const struct reserve_info *a, *b;
+
+	a = *((const struct reserve_info * const *)ax);
+	b = *((const struct reserve_info * const *)bx);
+
+	if (a->re.address < b->re.address)
+		return -1;
+	else if (a->re.address > b->re.address)
+		return 1;
+	else if (a->re.size < b->re.size)
+		return -1;
+	else if (a->re.size > b->re.size)
+		return 1;
+	else
+		return 0;
+}
+
+static void sort_reserve_entries(struct boot_info *bi)
+{
+	struct reserve_info *ri, **tbl;
+	int n = 0, i = 0;
+
+	for (ri = bi->reservelist;
+	     ri;
+	     ri = ri->next)
+		n++;
+
+	if (n == 0)
+		return;
+
+	tbl = xmalloc(n * sizeof(*tbl));
+
+	for (ri = bi->reservelist;
+	     ri;
+	     ri = ri->next)
+		tbl[i++] = ri;
+
+	qsort(tbl, n, sizeof(*tbl), cmp_reserve_info);
+
+	bi->reservelist = tbl[0];
+	for (i = 0; i < (n-1); i++)
+		tbl[i]->next = tbl[i+1];
+	tbl[n-1]->next = NULL;
+
+	free(tbl);
+}
+
+static int cmp_prop(const void *ax, const void *bx)
+{
+	const struct property *a, *b;
+
+	a = *((const struct property * const *)ax);
+	b = *((const struct property * const *)bx);
+
+	return strcmp(a->name, b->name);
+}
+
+static void sort_properties(struct node *node)
+{
+	int n = 0, i = 0;
+	struct property *prop, **tbl;
+
+	for_each_property(node, prop)
+		n++;
+
+	if (n == 0)
+		return;
+
+	tbl = xmalloc(n * sizeof(*tbl));
+
+	for_each_property(node, prop)
+		tbl[i++] = prop;
+
+	qsort(tbl, n, sizeof(*tbl), cmp_prop);
+
+	node->proplist = tbl[0];
+	for (i = 0; i < (n-1); i++)
+		tbl[i]->next = tbl[i+1];
+	tbl[n-1]->next = NULL;
+
+	free(tbl);
+}
+
+static int cmp_subnode(const void *ax, const void *bx)
+{
+	const struct node *a, *b;
+
+	a = *((const struct node * const *)ax);
+	b = *((const struct node * const *)bx);
+
+	return strcmp(a->name, b->name);
+}
+
+static void sort_subnodes(struct node *node)
+{
+	int n = 0, i = 0;
+	struct node *subnode, **tbl;
+
+	for_each_child(node, subnode)
+		n++;
+
+	if (n == 0)
+		return;
+
+	tbl = xmalloc(n * sizeof(*tbl));
+
+	for_each_child(node, subnode)
+		tbl[i++] = subnode;
+
+	qsort(tbl, n, sizeof(*tbl), cmp_subnode);
+
+	node->children = tbl[0];
+	for (i = 0; i < (n-1); i++)
+		tbl[i]->next_sibling = tbl[i+1];
+	tbl[n-1]->next_sibling = NULL;
+
+	free(tbl);
+}
+
+static void sort_node(struct node *node)
+{
+	struct node *c;
+
+	sort_properties(node);
+	sort_subnodes(node);
+	for_each_child(node, c)
+		sort_node(c);
+}
+
+void sort_tree(struct boot_info *bi)
+{
+	sort_reserve_entries(bi);
+	sort_node(bi->dt);
+}

tests/run_tests.sh

@@ -370,6 +370,13 @@ cmp_tests () {
     for tree in $wrongtrees; do
 	run_test dtbs_equal_unordered -n $basetree $tree
     done
+
+    # now dtc --sort
+    run_dtc_test -I dtb -O dtb -s -o $basetree.sorted.test.dtb $basetree
+    run_test dtbs_equal_unordered $basetree $basetree.sorted.test.dtb
+    run_dtc_test -I dtb -O dtb -s -o $basetree.reversed.sorted.test.dtb $basetree.reversed.test.dtb
+    run_test dtbs_equal_unordered $basetree.reversed.test.dtb $basetree.reversed.sorted.test.dtb
+    run_test dtbs_equal_ordered $basetree.sorted.test.dtb $basetree.reversed.sorted.test.dtb
 }
 
 dtbs_equal_tests () {