diff --git a/arch/sh/Kconfig b/arch/sh/Kconfig
index 5c075f5..7f217b3 100644
--- a/arch/sh/Kconfig
+++ b/arch/sh/Kconfig
@@ -193,6 +193,7 @@
 config CPU_SH2A
 	bool
 	select CPU_SH2
+	select UNCACHED_MAPPING
 
 config CPU_SH3
 	bool
diff --git a/arch/sh/include/asm/addrspace.h b/arch/sh/include/asm/addrspace.h
index 446b383..3d1ae2b 100644
--- a/arch/sh/include/asm/addrspace.h
+++ b/arch/sh/include/asm/addrspace.h
@@ -44,10 +44,10 @@
 /*
  * These will never work in 32-bit, don't even bother.
  */
-#define P1SEGADDR(a)	__futile_remapping_attempt
-#define P2SEGADDR(a)	__futile_remapping_attempt
-#define P3SEGADDR(a)	__futile_remapping_attempt
-#define P4SEGADDR(a)	__futile_remapping_attempt
+#define P1SEGADDR(a)	({ (void)(a); BUG(); NULL; })
+#define P2SEGADDR(a)	({ (void)(a); BUG(); NULL; })
+#define P3SEGADDR(a)	({ (void)(a); BUG(); NULL; })
+#define P4SEGADDR(a)	({ (void)(a); BUG(); NULL; })
 #endif
 #endif /* P1SEG */
 
diff --git a/arch/sh/mm/Kconfig b/arch/sh/mm/Kconfig
index 0937039..c3e61b3 100644
--- a/arch/sh/mm/Kconfig
+++ b/arch/sh/mm/Kconfig
@@ -79,7 +79,7 @@
 
 config 32BIT
 	bool
-	default y if CPU_SH5
+	default y if CPU_SH5 || !MMU
 
 config PMB
 	bool "Support 32-bit physical addressing through PMB"
diff --git a/arch/sh/mm/consistent.c b/arch/sh/mm/consistent.c
index 0387932..40733a9 100644
--- a/arch/sh/mm/consistent.c
+++ b/arch/sh/mm/consistent.c
@@ -79,21 +79,20 @@
 void dma_cache_sync(struct device *dev, void *vaddr, size_t size,
 		    enum dma_data_direction direction)
 {
-#if defined(CONFIG_CPU_SH5) || defined(CONFIG_PMB)
-	void *p1addr = vaddr;
-#else
-	void *p1addr = (void*) P1SEGADDR((unsigned long)vaddr);
-#endif
+	void *addr;
+
+	addr = __in_29bit_mode() ?
+	       (void *)P1SEGADDR((unsigned long)vaddr) : vaddr;
 
 	switch (direction) {
 	case DMA_FROM_DEVICE:		/* invalidate only */
-		__flush_invalidate_region(p1addr, size);
+		__flush_invalidate_region(addr, size);
 		break;
 	case DMA_TO_DEVICE:		/* writeback only */
-		__flush_wback_region(p1addr, size);
+		__flush_wback_region(addr, size);
 		break;
 	case DMA_BIDIRECTIONAL:		/* writeback and invalidate */
-		__flush_purge_region(p1addr, size);
+		__flush_purge_region(addr, size);
 		break;
 	default:
 		BUG();
diff --git a/arch/sh/mm/uncached.c b/arch/sh/mm/uncached.c
index 8a4eca5..a7767da 100644
--- a/arch/sh/mm/uncached.c
+++ b/arch/sh/mm/uncached.c
@@ -28,7 +28,7 @@
 
 void __init uncached_init(void)
 {
-#ifdef CONFIG_29BIT
+#if defined(CONFIG_29BIT) || !defined(CONFIG_MMU)
 	uncached_start = P2SEG;
 #else
 	uncached_start = memory_end;