diff --git a/include/asm-powerpc/dcr-generic.h b/include/asm-powerpc/dcr-generic.h
new file mode 100644
index 0000000..35b7159
--- /dev/null
+++ b/include/asm-powerpc/dcr-generic.h
@@ -0,0 +1,49 @@
+/*
+ * (c) Copyright 2006 Benjamin Herrenschmidt, IBM Corp.
+ *                    <benh@kernel.crashing.org>
+ *
+ *   This program is free software;  you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation; either version 2 of the License, or
+ *   (at your option) any later version.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY;  without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
+ *   the GNU General Public License for more details.
+ *
+ *   You should have received a copy of the GNU General Public License
+ *   along with this program;  if not, write to the Free Software
+ *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#ifndef _ASM_POWERPC_DCR_GENERIC_H
+#define _ASM_POWERPC_DCR_GENERIC_H
+#ifdef __KERNEL__
+#ifndef __ASSEMBLY__
+
+enum host_type_t {DCR_HOST_MMIO, DCR_HOST_NATIVE, DCR_HOST_INVALID};
+
+typedef struct {
+	enum host_type_t type;
+	union {
+		dcr_host_mmio_t mmio;
+		dcr_host_native_t native;
+	} host;
+} dcr_host_t;
+
+extern bool dcr_map_ok_generic(dcr_host_t host);
+
+extern dcr_host_t dcr_map_generic(struct device_node *dev, unsigned int dcr_n,
+			  unsigned int dcr_c);
+extern void dcr_unmap_generic(dcr_host_t host, unsigned int dcr_c);
+
+extern u32 dcr_read_generic(dcr_host_t host, unsigned int dcr_n);
+
+extern void dcr_write_generic(dcr_host_t host, unsigned int dcr_n, u32 value);
+
+#endif /* __ASSEMBLY__ */
+#endif /* __KERNEL__ */
+#endif /* _ASM_POWERPC_DCR_GENERIC_H */
+
+
diff --git a/include/asm-powerpc/dcr-mmio.h b/include/asm-powerpc/dcr-mmio.h
index 08532ff..acd491d 100644
--- a/include/asm-powerpc/dcr-mmio.h
+++ b/include/asm-powerpc/dcr-mmio.h
@@ -27,20 +27,26 @@
 	void __iomem *token;
 	unsigned int stride;
 	unsigned int base;
-} dcr_host_t;
+} dcr_host_mmio_t;
 
-#define DCR_MAP_OK(host)	((host).token != NULL)
+static inline bool dcr_map_ok_mmio(dcr_host_mmio_t host)
+{
+	return host.token != NULL;
+}
 
-extern dcr_host_t dcr_map(struct device_node *dev, unsigned int dcr_n,
-			  unsigned int dcr_c);
-extern void dcr_unmap(dcr_host_t host, unsigned int dcr_c);
+extern dcr_host_mmio_t dcr_map_mmio(struct device_node *dev,
+				    unsigned int dcr_n,
+				    unsigned int dcr_c);
+extern void dcr_unmap_mmio(dcr_host_mmio_t host, unsigned int dcr_c);
 
-static inline u32 dcr_read(dcr_host_t host, unsigned int dcr_n)
+static inline u32 dcr_read_mmio(dcr_host_mmio_t host, unsigned int dcr_n)
 {
 	return in_be32(host.token + ((host.base + dcr_n) * host.stride));
 }
 
-static inline void dcr_write(dcr_host_t host, unsigned int dcr_n, u32 value)
+static inline void dcr_write_mmio(dcr_host_mmio_t host,
+				  unsigned int dcr_n,
+				  u32 value)
 {
 	out_be32(host.token + ((host.base + dcr_n) * host.stride), value);
 }
diff --git a/include/asm-powerpc/dcr-native.h b/include/asm-powerpc/dcr-native.h
index f8398ce..72d2b72 100644
--- a/include/asm-powerpc/dcr-native.h
+++ b/include/asm-powerpc/dcr-native.h
@@ -26,14 +26,18 @@
 
 typedef struct {
 	unsigned int base;
-} dcr_host_t;
+} dcr_host_native_t;
 
-#define DCR_MAP_OK(host)	(1)
+static inline bool dcr_map_ok_native(dcr_host_native_t host)
+{
+	return 1;
+}
 
-#define dcr_map(dev, dcr_n, dcr_c)	((dcr_host_t){ .base = (dcr_n) })
-#define dcr_unmap(host, dcr_c)		do {} while (0)
-#define dcr_read(host, dcr_n)		mfdcr(dcr_n + host.base)
-#define dcr_write(host, dcr_n, value)	mtdcr(dcr_n + host.base, value)
+#define dcr_map_native(dev, dcr_n, dcr_c) \
+	((dcr_host_native_t){ .base = (dcr_n) })
+#define dcr_unmap_native(host, dcr_c)		do {} while (0)
+#define dcr_read_native(host, dcr_n)		mfdcr(dcr_n + host.base)
+#define dcr_write_native(host, dcr_n, value)	mtdcr(dcr_n + host.base, value)
 
 /* Device Control Registers */
 void __mtdcr(int reg, unsigned int val);
diff --git a/include/asm-powerpc/dcr.h b/include/asm-powerpc/dcr.h
index 9338d50..53b2830 100644
--- a/include/asm-powerpc/dcr.h
+++ b/include/asm-powerpc/dcr.h
@@ -20,14 +20,50 @@
 #ifndef _ASM_POWERPC_DCR_H
 #define _ASM_POWERPC_DCR_H
 #ifdef __KERNEL__
+#ifndef __ASSEMBLY__
 #ifdef CONFIG_PPC_DCR
 
 #ifdef CONFIG_PPC_DCR_NATIVE
 #include <asm/dcr-native.h>
-#else
+#endif
+
+#ifdef CONFIG_PPC_DCR_MMIO
 #include <asm/dcr-mmio.h>
 #endif
 
+
+/* Indirection layer for providing both NATIVE and MMIO support. */
+
+#if defined(CONFIG_PPC_DCR_NATIVE) && defined(CONFIG_PPC_DCR_MMIO)
+
+#include <asm/dcr-generic.h>
+
+#define DCR_MAP_OK(host)	dcr_map_ok_generic(host)
+#define dcr_map(dev, dcr_n, dcr_c) dcr_map_generic(dev, dcr_n, dcr_c)
+#define dcr_unmap(host, dcr_c) dcr_unmap_generic(host, dcr_c)
+#define dcr_read(host, dcr_n) dcr_read_generic(host, dcr_n)
+#define dcr_write(host, dcr_n, value) dcr_write_generic(host, dcr_n, value)
+
+#else
+
+#ifdef CONFIG_PPC_DCR_NATIVE
+typedef dcr_host_native_t dcr_host_t;
+#define DCR_MAP_OK(host)	dcr_map_ok_native(host)
+#define dcr_map(dev, dcr_n, dcr_c) dcr_map_native(dev, dcr_n, dcr_c)
+#define dcr_unmap(host, dcr_c) dcr_unmap_native(host, dcr_c)
+#define dcr_read(host, dcr_n) dcr_read_native(host, dcr_n)
+#define dcr_write(host, dcr_n, value) dcr_write_native(host, dcr_n, value)
+#else
+typedef dcr_host_mmio_t dcr_host_t;
+#define DCR_MAP_OK(host)	dcr_map_ok_mmio(host)
+#define dcr_map(dev, dcr_n, dcr_c) dcr_map_mmio(dev, dcr_n, dcr_c)
+#define dcr_unmap(host, dcr_c) dcr_unmap_mmio(host, dcr_c)
+#define dcr_read(host, dcr_n) dcr_read_mmio(host, dcr_n)
+#define dcr_write(host, dcr_n, value) dcr_write_mmio(host, dcr_n, value)
+#endif
+
+#endif /* defined(CONFIG_PPC_DCR_NATIVE) && defined(CONFIG_PPC_DCR_MMIO) */
+
 /*
  * On CONFIG_PPC_MERGE, we have additional helpers to read the DCR
  * base from the device-tree
@@ -41,5 +77,6 @@
 #endif /* CONFIG_PPC_MERGE */
 
 #endif /* CONFIG_PPC_DCR */
+#endif /* __ASSEMBLY__ */
 #endif /* __KERNEL__ */
 #endif /* _ASM_POWERPC_DCR_H */