#define mmiowb() do {} while (0)
#endif
+#ifndef __io_br
+#define __io_br() barrier()
+#endif
+
+/* prevent prefetching of coherent DMA data ahead of a dma-complete */
+#ifndef __io_ar
+#ifdef rmb
+#define __io_ar() rmb()
+#else
+#define __io_ar() barrier()
+#endif
+#endif
+
+/* flush writes to coherent DMA data before possibly triggering a DMA read */
+#ifndef __io_bw
+#ifdef wmb
+#define __io_bw() wmb()
+#else
+#define __io_bw() barrier()
+#endif
+#endif
+
+/* serialize device access against a spin_unlock, usually handled there. */
+#ifndef __io_aw
+#define __io_aw() barrier()
+#endif
+
+#ifndef __io_pbw
+#define __io_pbw() __io_bw()
+#endif
+
+#ifndef __io_paw
+#define __io_paw() __io_aw()
+#endif
+
+#ifndef __io_pbr
+#define __io_pbr() __io_br()
+#endif
+
+#ifndef __io_par
+#define __io_par() __io_ar()
+#endif
+
+
/*
* __raw_{read,write}{b,w,l,q}() access memory in native endianness.
*