diff --git a/include/linux/clocksource.h b/include/linux/clocksource.h
index c918fbd..d4646b4 100644
--- a/include/linux/clocksource.h
+++ b/include/linux/clocksource.h
@@ -337,6 +337,14 @@
 
 extern void timekeeping_notify(struct clocksource *clock);
 
+extern cycle_t clocksource_mmio_readl_up(struct clocksource *);
+extern cycle_t clocksource_mmio_readl_down(struct clocksource *);
+extern cycle_t clocksource_mmio_readw_up(struct clocksource *);
+extern cycle_t clocksource_mmio_readw_down(struct clocksource *);
+
+extern int clocksource_mmio_init(void __iomem *, const char *,
+	unsigned long, int, unsigned, cycle_t (*)(struct clocksource *));
+
 extern int clocksource_i8253_init(void);
 
 #endif /* _LINUX_CLOCKSOURCE_H */