of/address: Add of_range_to_resource() helper

A few users need to convert a specific "ranges" entry into a struct
resource. Add a helper to similar to of_address_to_resource(). The
existing of_pci_range_to_resource() helper isn't really PCI specific,
so it can be used with the CONFIG_PCI check dropped.

Link: https://lore.kernel.org/r/20230328-dt-address-helpers-v1-2-e2456c3e77ab@kernel.org
Signed-off-by: Rob Herring <robh@kernel.org>

Author: robherring

drivers/of/address.c

@@ -229,9 +229,6 @@ int of_pci_range_to_resource(struct of_pci_range *range,
 	res->parent = res->child = res->sibling = NULL;
 	res->name = np->full_name;
 
-	if (!IS_ENABLED(CONFIG_PCI))
-		return -ENOSYS;
-
 	if (res->flags & IORESOURCE_IO) {
 		unsigned long port;
 		err = pci_register_io_range(&np->fwnode, range->cpu_addr,
@@ -263,6 +260,34 @@ int of_pci_range_to_resource(struct of_pci_range *range,
 }
 EXPORT_SYMBOL(of_pci_range_to_resource);
 
+/*
+ * of_range_to_resource - Create a resource from a ranges entry
+ * @np:		device node where the range belongs to
+ * @index:	the 'ranges' index to convert to a resource
+ * @res:	pointer to a valid resource that will be updated to
+ *              reflect the values contained in the range.
+ *
+ * Returns ENOENT if the entry is not found or EINVAL if the range cannot be
+ * converted to resource.
+ */
+int of_range_to_resource(struct device_node *np, int index, struct resource *res)
+{
+	int ret, i = 0;
+	struct of_range_parser parser;
+	struct of_range range;
+
+	ret = of_range_parser_init(&parser, np);
+	if (ret)
+		return ret;
+
+	for_each_of_range(&parser, &range)
+		if (i++ == index)
+			return of_pci_range_to_resource(&range, np, res);
+
+	return -ENOENT;
+}
+EXPORT_SYMBOL(of_range_to_resource);
+
 /*
  * ISA bus specific translator
  */

drivers/of/unittest.c

@@ -1013,7 +1013,8 @@ static void __init of_unittest_bus_ranges(void)
 	struct device_node *np;
 	struct of_range range;
 	struct of_range_parser parser;
-	int i = 0;
+	struct resource res;
+	int ret, i = 0;
 
 	np = of_find_node_by_path("/testcase-data/address-tests");
 	if (!np) {
@@ -1026,6 +1027,19 @@ static void __init of_unittest_bus_ranges(void)
 		return;
 	}
 
+	ret = of_range_to_resource(np, 1, &res);
+	unittest(!ret, "of_range_to_resource returned error (%d) node %pOF\n",
+		ret, np);
+	unittest(resource_type(&res) == IORESOURCE_MEM,
+		"of_range_to_resource wrong resource type on node %pOF res=%pR\n",
+		np, &res);
+	unittest(res.start == 0xd0000000,
+		"of_range_to_resource wrong resource start address on node %pOF res=%pR\n",
+		np, &res);
+	unittest(resource_size(&res) == 0x20000000,
+		"of_range_to_resource wrong resource start address on node %pOF res=%pR\n",
+		np, &res);
+
 	/*
 	 * Get the "ranges" from the device tree
 	 */

include/linux/of_address.h

@@ -68,6 +68,8 @@ extern int of_pci_address_to_resource(struct device_node *dev, int bar,
 extern int of_pci_range_to_resource(struct of_pci_range *range,
 				    struct device_node *np,
 				    struct resource *res);
+extern int of_range_to_resource(struct device_node *np, int index,
+				struct resource *res);
 extern bool of_dma_is_coherent(struct device_node *np);
 #else /* CONFIG_OF_ADDRESS */
 static inline void __iomem *of_io_request_and_map(struct device_node *device,
@@ -120,6 +122,12 @@ static inline int of_pci_range_to_resource(struct of_pci_range *range,
 	return -ENOSYS;
 }
 
+static inline int of_range_to_resource(struct device_node *np, int index,
+				       struct resource *res)
+{
+	return -ENOSYS;
+}
+
 static inline bool of_dma_is_coherent(struct device_node *np)
 {
 	return false;