diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index e668994c..9851065 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -7,6 +7,10 @@ config SYS_ARCH
 config ARM64
 	bool
 
+config DMA_ADDR_T_64BIT
+	bool
+	default y if ARM64
+
 config HAS_VBAR
         bool
 
diff --git a/arch/arm/include/asm/types.h b/arch/arm/include/asm/types.h
index 388058e..d108915 100644
--- a/arch/arm/include/asm/types.h
+++ b/arch/arm/include/asm/types.h
@@ -46,16 +46,29 @@ typedef unsigned long long u64;
 #endif	/* CONFIG_ARM64 */
 
 #ifdef CONFIG_PHYS_64BIT
-typedef unsigned long long dma_addr_t;
 typedef unsigned long long phys_addr_t;
 typedef unsigned long long phys_size_t;
 #else
 /* DMA addresses are 32-bits wide */
-typedef u32 dma_addr_t;
 typedef unsigned long phys_addr_t;
 typedef unsigned long phys_size_t;
 #endif
 
+/*
+ * A dma_addr_t can hold any valid DMA address, i.e., any address returned
+ * by the DMA API.
+ *
+ * If the DMA API only uses 32-bit addresses, dma_addr_t need only be 32
+ * bits wide.  Bus addresses, e.g., PCI BARs, may be wider than 32 bits,
+ * but drivers do memory-mapped I/O to ioremapped kernel virtual addresses,
+ * so they don't care about the size of the actual bus addresses.
+ */
+#ifdef CONFIG_DMA_ADDR_T_64BIT
+typedef unsigned long long dma_addr_t;
+#else
+typedef u32 dma_addr_t;
+#endif
+
 #endif /* __KERNEL__ */
 
 typedef unsigned long resource_size_t;