1 files changed, 56 insertions, 6 deletions

diff --git a/drivers/of/address.c b/drivers/of/address.c
index c34ac33b7338..4c0b169ef9bf 100644
--- a/drivers/of/address.c
+++ b/drivers/of/address.c
@@ -626,6 +626,47 @@ u64 of_translate_dma_address(struct device_node *dev, const __be32 *in_addr)
 }
 EXPORT_SYMBOL(of_translate_dma_address);
 
+/**
+ * of_translate_dma_region - Translate device tree address and size tuple
+ * @dev: device tree node for which to translate
+ * @prop: pointer into array of cells
+ * @start: return value for the start of the DMA range
+ * @length: return value for the length of the DMA range
+ *
+ * Returns a pointer to the cell immediately following the translated DMA region.
+ */
+const __be32 *of_translate_dma_region(struct device_node *dev, const __be32 *prop,
+				      phys_addr_t *start, size_t *length)
+{
+	struct device_node *parent;
+	u64 address, size;
+	int na, ns;
+
+	parent = __of_get_dma_parent(dev);
+	if (!parent)
+		return NULL;
+
+	na = of_bus_n_addr_cells(parent);
+	ns = of_bus_n_size_cells(parent);
+
+	of_node_put(parent);
+
+	address = of_translate_dma_address(dev, prop);
+	if (address == OF_BAD_ADDR)
+		return NULL;
+
+	size = of_read_number(prop + na, ns);
+
+	if (start)
+		*start = address;
+
+	if (length)
+		*length = size;
+
+	return prop + na + ns;
+}
+EXPORT_SYMBOL(of_translate_dma_region);
+
 const __be32 *__of_get_address(struct device_node *dev, int index, int bar_no,
 			       u64 *size, unsigned int *flags)
 {
@@ -965,8 +1006,19 @@ int of_dma_get_range(struct device_node *np, const struct bus_dma_region **map)
 	}
 
 	of_dma_range_parser_init(&parser, node);
-	for_each_of_range(&parser, &range)
+	for_each_of_range(&parser, &range) {
+		if (range.cpu_addr == OF_BAD_ADDR) {
+			pr_err("translation of DMA address(%llx) to CPU address failed node(%pOF)\n",
+			       range.bus_addr, node);
+			continue;
+		}
 		num_ranges++;
+	}
+
+	if (!num_ranges) {
+		ret = -EINVAL;
+		goto out;
+	}
 
 	r = kcalloc(num_ranges + 1, sizeof(*r), GFP_KERNEL);
 	if (!r) {
@@ -975,18 +1027,16 @@ int of_dma_get_range(struct device_node *np, const struct bus_dma_region **map)
 	}
 
 	/*
-	 * Record all info in the generic DMA ranges array for struct device.
+	 * Record all info in the generic DMA ranges array for struct device,
+	 * returning an error if we don't find any parsable ranges.
 	 */
 	*map = r;
 	of_dma_range_parser_init(&parser, node);
 	for_each_of_range(&parser, &range) {
 		pr_debug("dma_addr(%llx) cpu_addr(%llx) size(%llx)\n",
 			 range.bus_addr, range.cpu_addr, range.size);
-		if (range.cpu_addr == OF_BAD_ADDR) {
-			pr_err("translation of DMA address(%llx) to CPU address failed node(%pOF)\n",
-			       range.bus_addr, node);
+		if (range.cpu_addr == OF_BAD_ADDR)
 			continue;
-		}
 		r->cpu_start = range.cpu_addr;
 		r->dma_start = range.bus_addr;
 		r->size = range.size;