[IA64] swiotlb abstraction (e.g. for Xen)

Add abstraction so that the file can be used by environments other than IA64
and EM64T, namely for Xen.
Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Tony Luck <tony.luck@intel.com>

include/asm-ia64/swiotlb.h

+#ifndef _ASM_SWIOTLB_H
+#define _ASM_SWIOTLB_H 1
+
+#include <asm/machvec.h>
+
+#define SWIOTLB_ARCH_NEED_LATE_INIT
+#define SWIOTLB_ARCH_NEED_ALLOC
+
+#endif /* _ASM_SWIOTLB_H */

include/asm-x86_64/swiotlb.h

@@ -44,6 +44,7 @@ extern void swiotlb_init(void);
 extern int swiotlb_force;
 
 #ifdef CONFIG_SWIOTLB
+#define SWIOTLB_ARCH_NEED_ALLOC
 extern int swiotlb;
 #else
 #define swiotlb 0