3 files changed, 97 insertions, 24 deletions

diff --git a/drivers/of/device.c b/drivers/of/device.c
index 5053e5d532cc..c80426510ec2 100644
--- a/drivers/of/device.c
+++ b/drivers/of/device.c
@@ -35,44 +35,35 @@ EXPORT_SYMBOL(of_match_device);
 static void
 of_dma_set_restricted_buffer(struct device *dev, struct device_node *np)
 {
-	struct device_node *node, *of_node = dev->of_node;
-	int count, i;
+	struct device_node *of_node = dev->of_node;
+	struct of_phandle_iterator it;
+	int rc, i = 0;
 
 	if (!IS_ENABLED(CONFIG_DMA_RESTRICTED_POOL))
 		return;
 
-	count = of_property_count_elems_of_size(of_node, "memory-region",
-						sizeof(u32));
 	/*
 	 * If dev->of_node doesn't exist or doesn't contain memory-region, try
 	 * the OF node having DMA configuration.
 	 */
-	if (count <= 0) {
+	if (!of_property_present(of_node, "memory-region"))
 		of_node = np;
-		count = of_property_count_elems_of_size(
-			of_node, "memory-region", sizeof(u32));
-	}
 
-	for (i = 0; i < count; i++) {
-		node = of_parse_phandle(of_node, "memory-region", i);
+	of_for_each_phandle(&it, rc, of_node, "memory-region", NULL, 0) {
 		/*
 		 * There might be multiple memory regions, but only one
 		 * restricted-dma-pool region is allowed.
 		 */
-		if (of_device_is_compatible(node, "restricted-dma-pool") &&
-		    of_device_is_available(node)) {
-			of_node_put(node);
+		if (of_device_is_compatible(it.node, "restricted-dma-pool") &&
+		    of_device_is_available(it.node)) {
+			if (of_reserved_mem_device_init_by_idx(dev, of_node, i))
+				dev_warn(dev, "failed to initialise \"restricted-dma-pool\" memory node\n");
+			of_node_put(it.node);
 			break;
 		}
-		of_node_put(node);
+		i++;
 	}
 
-	/*
-	 * Attempt to initialize a restricted-dma-pool region if one was found.
-	 * Note that count can hold a negative error code.
-	 */
-	if (i < count && of_reserved_mem_device_init_by_idx(dev, of_node, i))
-		dev_warn(dev, "failed to initialise \"restricted-dma-pool\" memory node\n");
 }
 
 /**
diff --git a/drivers/of/of_reserved_mem.c b/drivers/of/of_reserved_mem.c
index ee2e31522d7e..77016c0cc296 100644
--- a/drivers/of/of_reserved_mem.c
+++ b/drivers/of/of_reserved_mem.c
@@ -12,6 +12,7 @@
 #define pr_fmt(fmt)	"OF: reserved mem: " fmt
 
 #include <linux/err.h>
+#include <linux/ioport.h>
 #include <linux/libfdt.h>
 #include <linux/of.h>
 #include <linux/of_fdt.h>
@@ -740,3 +741,82 @@ struct reserved_mem *of_reserved_mem_lookup(struct device_node *np)
 	return NULL;
 }
 EXPORT_SYMBOL_GPL(of_reserved_mem_lookup);
+
+/**
+ * of_reserved_mem_region_to_resource() - Get a reserved memory region as a resource
+ * @np:		node containing 'memory-region' property
+ * @idx:	index of 'memory-region' property to lookup
+ * @res:	Pointer to a struct resource to fill in with reserved region
+ *
+ * This function allows drivers to lookup a node's 'memory-region' property
+ * entries by index and return a struct resource for the entry.
+ *
+ * Returns 0 on success with @res filled in. Returns -ENODEV if 'memory-region'
+ * is missing or unavailable, -EINVAL for any other error.
+ */
+int of_reserved_mem_region_to_resource(const struct device_node *np,
+				       unsigned int idx, struct resource *res)
+{
+	struct reserved_mem *rmem;
+
+	if (!np)
+		return -EINVAL;
+
+	struct device_node __free(device_node) *target = of_parse_phandle(np, "memory-region", idx);
+	if (!target || !of_device_is_available(target))
+		return -ENODEV;
+
+	rmem = of_reserved_mem_lookup(target);
+	if (!rmem)
+		return -EINVAL;
+
+	resource_set_range(res, rmem->base, rmem->size);
+	res->name = rmem->name;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(of_reserved_mem_region_to_resource);
+
+/**
+ * of_reserved_mem_region_to_resource_byname() - Get a reserved memory region as a resource
+ * @np:		node containing 'memory-region' property
+ * @name:	name of 'memory-region' property entry to lookup
+ * @res:	Pointer to a struct resource to fill in with reserved region
+ *
+ * This function allows drivers to lookup a node's 'memory-region' property
+ * entries by name and return a struct resource for the entry.
+ *
+ * Returns 0 on success with @res filled in, or a negative error-code on
+ * failure.
+ */
+int of_reserved_mem_region_to_resource_byname(const struct device_node *np,
+					      const char *name,
+					      struct resource *res)
+{
+	int idx;
+
+	if (!name)
+		return -EINVAL;
+
+	idx = of_property_match_string(np, "memory-region-names", name);
+	if (idx < 0)
+		return idx;
+
+	return of_reserved_mem_region_to_resource(np, idx, res);
+}
+EXPORT_SYMBOL_GPL(of_reserved_mem_region_to_resource_byname);
+
+/**
+ * of_reserved_mem_region_count() - Return the number of 'memory-region' entries
+ * @np:		node containing 'memory-region' property
+ *
+ * This function allows drivers to retrieve the number of entries for a node's
+ * 'memory-region' property.
+ *
+ * Returns the number of entries on success, or negative error code on a
+ * malformed property.
+ */
+int of_reserved_mem_region_count(const struct device_node *np)
+{
+	return of_count_phandle_with_args(np, "memory-region", NULL);
+}
+EXPORT_SYMBOL_GPL(of_reserved_mem_region_count);
diff --git a/drivers/of/unittest.c b/drivers/of/unittest.c
index 64d301893af7..eeb370e0f507 100644
--- a/drivers/of/unittest.c
+++ b/drivers/of/unittest.c
@@ -2029,15 +2029,16 @@ static int __init unittest_data_add(void)
 	rc = of_resolve_phandles(unittest_data_node);
 	if (rc) {
 		pr_err("%s: Failed to resolve phandles (rc=%i)\n", __func__, rc);
-		of_overlay_mutex_unlock();
-		return -EINVAL;
+		rc = -EINVAL;
+		goto unlock;
 	}
 
 	/* attach the sub-tree to live tree */
 	if (!of_root) {
 		pr_warn("%s: no live tree to attach sub-tree\n", __func__);
 		kfree(unittest_data);
-		return -ENODEV;
+		rc = -ENODEV;
+		goto unlock;
 	}
 
 	EXPECT_BEGIN(KERN_INFO,
@@ -2056,9 +2057,10 @@ static int __init unittest_data_add(void)
 	EXPECT_END(KERN_INFO,
 		   "Duplicate name in testcase-data, renamed to \"duplicate-name#1\"");
 
+unlock:
 	of_overlay_mutex_unlock();
 
-	return 0;
+	return rc;
 }
 
 #ifdef CONFIG_OF_OVERLAY