Index: uspace/lib/usb/include/usb/dma_buffer.h
===================================================================
--- uspace/lib/usb/include/usb/dma_buffer.h	(revision 98893ede399d6eed12edddf404da1f101f415345)
+++ uspace/lib/usb/include/usb/dma_buffer.h	(revision 7cba9f73d4bf1357e8b015cf70d85178e89a2c01)
@@ -32,5 +32,5 @@
  * @brief USB host controller library: DMA buffer helpers
  *
- * Simplifies usage of bounce buffers.
+ * Simplifies usage of bounce buffers
  *
  * Currently the minimum size allocated is a page, which is wasteful. Could be
@@ -46,6 +46,8 @@
 
 typedef const struct dma_policy {
-	bool use64;		/**< Whether to use more than initial 4GiB of memory */
-	size_t alignment;	/**< What alignment is needed. At most PAGE_SIZE. */
+	unsigned flags;
+
+#define DMA_POLICY_F_4GiB	(1<<0)	/**< Must use only 32-bit addresses */
+#define DMA_POLICY_F_CONTIGUOUS	(1<<1)	/**< Pages must follow each other physically */
 } dma_policy_t;
 
@@ -56,7 +58,9 @@
 
 extern int dma_buffer_alloc(dma_buffer_t *db, size_t size);
-extern int dma_buffer_alloc_policy(dma_buffer_t *, size_t, const dma_policy_t *);
+extern int dma_buffer_alloc_policy(dma_buffer_t *, size_t, dma_policy_t *);
 extern void dma_buffer_free(dma_buffer_t *);
 extern uintptr_t dma_buffer_phys(const dma_buffer_t *, void *);
+
+extern bool dma_buffer_check_policy(const void *, size_t, dma_policy_t *);
 
 static inline int dma_buffer_is_set(dma_buffer_t *db)