diff --git a/arch/sh/include/asm/io.h b/arch/sh/include/asm/io.h
index 9aa9438c66c3..6a0dd8c1e0a9 100644
--- a/arch/sh/include/asm/io.h
+++ b/arch/sh/include/asm/io.h
@@ -22,6 +22,7 @@
  * for old compat code for I/O offseting to SuperIOs, all of which are
  * better handled through the machvec ioport mapping routines these days.
  */
+#include <linux/errno.h>
 #include <asm/cache.h>
 #include <asm/system.h>
 #include <asm/addrspace.h>
@@ -239,7 +240,7 @@ void __iounmap(void __iomem *addr);
 
 #ifdef CONFIG_IOREMAP_FIXED
 extern void __iomem *ioremap_fixed(resource_size_t, unsigned long, pgprot_t);
-extern void iounmap_fixed(void __iomem *);
+extern int iounmap_fixed(void __iomem *);
 extern void ioremap_fixed_init(void);
 #else
 static inline void __iomem *
@@ -249,7 +250,7 @@ ioremap_fixed(resource_size t phys_addr, unsigned long size, pgprot_t prot)
 }
 
 static inline void ioremap_fixed_init(void) { }
-static inline void iounmap_fixed(void __iomem *addr) { }
+static inline int iounmap_fixed(void __iomem *addr) { return -EINVAL; }
 #endif
 
 static inline void __iomem *
diff --git a/arch/sh/mm/ioremap_fixed.c b/arch/sh/mm/ioremap_fixed.c
index 3a9d3d88fe8d..425f6c6bf250 100644
--- a/arch/sh/mm/ioremap_fixed.c
+++ b/arch/sh/mm/ioremap_fixed.c
@@ -103,7 +103,7 @@ ioremap_fixed(resource_size_t phys_addr, unsigned long size, pgprot_t prot)
 	return map->addr;
 }
 
-void __init iounmap_fixed(void __iomem *addr)
+int iounmap_fixed(void __iomem *addr)
 {
 	enum fixed_addresses idx;
 	unsigned long virt_addr;
@@ -122,8 +122,11 @@ void __init iounmap_fixed(void __iomem *addr)
 		}
 	}
 
+	/*
+	 * If we don't match, it's not for us.
+	 */
 	if (slot < 0)
-		return;
+		return -EINVAL;
 
 	virt_addr = (unsigned long)addr;
 
@@ -141,4 +144,6 @@ void __init iounmap_fixed(void __iomem *addr)
 
 	map->size = 0;
 	map->addr = NULL;
+
+	return 0;
 }