Warn on node name unit-address presence/absence mismatch

ePAPR 1.1 section 2.2.1.1 "Node Name Requirements" specifies that any
node that has a reg property must include a unit address in its name
with value matching the first entry in its reg property. Conversely, if
a node does not have a reg property, the node name must not include a
unit address. Also allow ranges property as it is deemed valid, but ePAPR
is not clear about it.

Implement a check for this. The code doesn't validate the format of the
unit address; ePAPR implies this may vary from (containing bus) binding
to binding, so doing so would be much more complex.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
[robh: also allow non-empty ranges]
Signed-off-by: Rob Herring <robh@kernel.org>
[moved new test in check_table]
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

checks.c

@@ -294,6 +294,30 @@ static void check_node_name_format(struct check *c, struct node *dt,
 }
 NODE_ERROR(node_name_format, NULL, &node_name_chars);
 
+static void check_unit_address_vs_reg(struct check *c, struct node *dt,
+			     struct node *node)
+{
+	const char *unitname = get_unitname(node);
+	struct property *prop = get_property(node, "reg");
+
+	if (!prop) {
+		prop = get_property(node, "ranges");
+		if (prop && !prop->val.len)
+			prop = NULL;
+	}
+
+	if (prop) {
+		if (!unitname[0])
+			FAIL(c, "Node %s has a reg or ranges property, but no unit name",
+			    node->fullpath);
+	} else {
+		if (unitname[0])
+			FAIL(c, "Node %s has a unit name, but no reg property",
+			    node->fullpath);
+	}
+}
+NODE_WARNING(unit_address_vs_reg, NULL);
+
 static void check_property_name_chars(struct check *c, struct node *dt,
 				      struct node *node, struct property *prop)
 {
@@ -667,6 +691,8 @@ static struct check *check_table[] = {
 
 	&addr_size_cells, &reg_format, &ranges_format,
 
+	&unit_address_vs_reg,
+
 	&avoid_default_addr_size,
 	&obsolete_chosen_interrupt_controller,
 

tests/reg-without-unit-addr.dts

@@ -0,0 +1,10 @@
+/dts-v1/;
+
+/ {
+	#address-cells = <1>;
+	#size-cells = <1>;
+
+	node {
+		reg = <0 1>;
+	};
+};

tests/run_tests.sh

@@ -445,6 +445,8 @@ dtc_tests () {
     check_tests reg-ranges-root.dts reg_format ranges_format
     check_tests default-addr-size.dts avoid_default_addr_size
     check_tests obsolete-chosen-interrupt-controller.dts obsolete_chosen_interrupt_controller
+    check_tests reg-without-unit-addr.dts unit_address_vs_reg
+    check_tests unit-addr-without-reg.dts unit_address_vs_reg
     run_sh_test dtc-checkfails.sh node_name_chars -- -I dtb -O dtb bad_node_char.dtb
     run_sh_test dtc-checkfails.sh node_name_format -- -I dtb -O dtb bad_node_format.dtb
     run_sh_test dtc-checkfails.sh prop_name_chars -- -I dtb -O dtb bad_prop_char.dtb

tests/unit-addr-without-reg.dts

@@ -0,0 +1,9 @@
+/dts-v1/;
+
+/ {
+	#address-cells = <1>;
+	#size-cells = <1>;
+
+	node@1 {
+	};
+};