diff --git a/arch/powerpc/include/asm/io.h b/arch/powerpc/include/asm/io.h
index a3855b81eada2ed893a6d272198e6add4b85752e..f94ef4213e9d03f80e1c0f180ea9a75d966358ad 100644
--- a/arch/powerpc/include/asm/io.h
+++ b/arch/powerpc/include/asm/io.h
@@ -20,6 +20,14 @@ extern int check_legacy_ioport(unsigned long base_port);
 #define _PNPWRP		0xa79
 #define PNPBIOS_BASE	0xf000
 
+#if defined(CONFIG_PPC64) && defined(CONFIG_PCI)
+extern struct pci_dev *isa_bridge_pcidev;
+/*
+ * has legacy ISA devices ?
+ */
+#define arch_has_dev_port()	(isa_bridge_pcidev != NULL)
+#endif
+
 #include <linux/device.h>
 #include <linux/io.h>
 
diff --git a/drivers/char/mem.c b/drivers/char/mem.c
index 67c3371723cc3b2f953fe528c6c4eef3af8f0e3a..e5eedfa24c91010bd8358db7b7076e4f0af6ad1b 100644
--- a/drivers/char/mem.c
+++ b/drivers/char/mem.c
@@ -27,14 +27,16 @@
 #include <linux/splice.h>
 #include <linux/pfn.h>
 #include <linux/export.h>
+#include <linux/io.h>
 
 #include <asm/uaccess.h>
-#include <asm/io.h>
 
 #ifdef CONFIG_IA64
 # include <linux/efi.h>
 #endif
 
+#define DEVPORT_MINOR	4
+
 static inline unsigned long size_inside_page(unsigned long start,
 					     unsigned long size)
 {
@@ -894,6 +896,13 @@ static int __init chr_dev_init(void)
 	for (minor = 1; minor < ARRAY_SIZE(devlist); minor++) {
 		if (!devlist[minor].name)
 			continue;
+
+		/*
+		 * Create /dev/port? 
+		 */
+		if ((minor == DEVPORT_MINOR) && !arch_has_dev_port())
+			continue;
+
 		device_create(mem_class, NULL, MKDEV(MEM_MAJOR, minor),
 			      NULL, devlist[minor].name);
 	}
diff --git a/include/linux/io.h b/include/linux/io.h
index 7fd2d2138bf3de8130e5660922a32fe81a47f22b..069e4075f8720331f99696e34a563d4ac1b76e35 100644
--- a/include/linux/io.h
+++ b/include/linux/io.h
@@ -67,4 +67,13 @@ int check_signature(const volatile void __iomem *io_addr,
 			const unsigned char *signature, int length);
 void devm_ioremap_release(struct device *dev, void *res);
 
+/*
+ * Some systems do not have legacy ISA devices.
+ * /dev/port is not a valid interface on these systems.
+ * So for those archs, <asm/io.h> should define the following symbol.
+ */
+#ifndef arch_has_dev_port
+#define arch_has_dev_port()     (1)
+#endif
+
 #endif /* _LINUX_IO_H */