libfdt: Add helpers to read #address-cells and #size-cells

This patch makes a small start on libfdt functions which actually help to
parse the contents of device trees, rather than purely manipulating the
tree's structure.

We add simple helpers to read and sanity check the #address-cells and
#size-cells values for a given node.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

tests/.gitignore

@@ -3,6 +3,7 @@
 *.test.dts
 tmp.*
 /add_subnode_with_nops
+/addr_size_cells
 /appendprop[12]
 /asm_tree_dump
 /boot-cpuid

tests/Makefile.tests

@@ -8,6 +8,7 @@ LIB_TESTS_L = get_mem_rsv \
 	char_literal \
 	sized_cells \
 	notfound \
+	addr_size_cells \
 	setprop_inplace nop_property nop_node \
 	sw_tree1 \
 	move_and_save mangle-layout nopulate \

tests/addr_size_cells.c

@@ -0,0 +1,64 @@
+/*
+ * libfdt - Flat Device Tree manipulation
+ *	Testcase for #address-cells and #size-cells handling
+ * Copyright (C) 2014 David Gibson, <david@gibson.dropbear.id.au>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public License
+ * as published by the Free Software Foundation; either version 2.1 of
+ * the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <stdint.h>
+
+#include <libfdt.h>
+
+#include "tests.h"
+#include "testdata.h"
+
+static void check_node(const void *fdt, const char *path, int ac, int sc)
+{
+	int offset;
+	int xac, xsc;
+
+	offset = fdt_path_offset(fdt, path);
+	if (offset < 0)
+		FAIL("Couldn't find path %s", path);
+
+	xac = fdt_address_cells(fdt, offset);
+	xsc = fdt_size_cells(fdt, offset);
+
+	if (xac != ac)
+		FAIL("Address cells for %s is %d instead of %d\n",
+		     path, xac, ac);
+	if (xsc != sc)
+		FAIL("Size cells for %s is %d instead of %d\n",
+		     path, xsc, sc);
+}
+
+int main(int argc, char *argv[])
+{
+	void *fdt;
+
+	if (argc != 2)
+		CONFIG("Usage: %s <dtb file>\n", argv[0]);
+
+	test_init(argc, argv);
+	fdt = load_blob(argv[1]);
+
+	check_node(fdt, "/", 2, 2);
+	check_node(fdt, "/identity-bus@0", 2, 2);
+	check_node(fdt, "/simple-bus@1000000", 2, 1);
+	PASS();
+}

tests/addresses.dts

@@ -0,0 +1,15 @@
+/dts-v1/;
+
+/ {
+	compatible = "test_addresses";
+	#address-cells = <2>;
+	#size-cells = <2>;
+
+	identity-bus@0 {
+	};
+
+	simple-bus@1000000 {
+		#address-cells = <2>;
+		#size-cells = <1>;
+	};
+};

tests/run_tests.sh

@@ -188,6 +188,9 @@ ALL_LAYOUTS="mts mst tms tsm smt stm"
 libfdt_tests () {
     tree1_tests test_tree1.dtb
 
+    run_dtc_test -I dts -O dtb -o addresses.test.dtb addresses.dts
+    run_test addr_size_cells addresses.test.dtb
+
     # Sequential write tests
     run_test sw_tree1
     tree1_tests sw_tree1.test.dtb