s390/pci: DMA support

Add DMA IOMMU support using 4K page table entries. Implement dma_map_ops.

Signed-off-by: Jan Glauber <jang@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/arch/s390/include/asm/dma.h b/arch/s390/include/asm/dma.h
index 6fb6de4..de015d8 100644
--- a/arch/s390/include/asm/dma.h
+++ b/arch/s390/include/asm/dma.h
@@ -1,14 +1,13 @@
+#ifndef _ASM_S390_DMA_H
+#define _ASM_S390_DMA_H
+
+#include <asm/io.h>
+
 /*
- *  S390 version
+ * MAX_DMA_ADDRESS is ambiguous because on s390 its completely unrelated
+ * to DMA. It _is_ used for the s390 memory zone split at 2GB caused
+ * by the 31 bit heritage.
  */
-
-#ifndef _ASM_DMA_H
-#define _ASM_DMA_H
-
-#include <asm/io.h>		/* need byte IO */
-
 #define MAX_DMA_ADDRESS         0x80000000
 
-#define free_dma(x)	do { } while (0)
-
-#endif /* _ASM_DMA_H */
+#endif /* _ASM_S390_DMA_H */