diff --git a/arch/mips/lib/Makefile b/arch/mips/lib/Makefile
index fabeb83..88ef1c5 100644
--- a/arch/mips/lib/Makefile
+++ b/arch/mips/lib/Makefile
@@ -6,6 +6,8 @@
 #
 
 obj-y	+= board.o
+obj-y	+= io.o
+
 obj-$(CONFIG_CMD_BOOTM) += bootm.o
 
 lib-$(CONFIG_USE_PRIVATE_LIBGCC) += ashldi3.o ashrdi3.o lshrdi3.o
diff --git a/arch/mips/lib/board.c b/arch/mips/lib/board.c
index 9e6ba15..317c825 100644
--- a/arch/mips/lib/board.c
+++ b/arch/mips/lib/board.c
@@ -27,12 +27,6 @@
 
 static char *failed = "*** failed ***\n";
 
-/*
- * mips_io_port_base is the begin of the address space to which x86 style
- * I/O ports are mapped.
- */
-const unsigned long mips_io_port_base = -1;
-
 int __board_early_init_f(void)
 {
 	/*
diff --git a/arch/mips/lib/io.c b/arch/mips/lib/io.c
new file mode 100644
index 0000000..b2d4a09
--- /dev/null
+++ b/arch/mips/lib/io.c
@@ -0,0 +1,12 @@
+/*
+ * (C) Copyright 2003
+ * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+/*
+ * mips_io_port_base is the begin of the address space to which x86 style
+ * I/O ports are mapped.
+ */
+const unsigned long mips_io_port_base = -1;