diff --git a/drivers/clocksource/mmio.c b/drivers/clocksource/mmio.c
index 19a6b3f4d9cf02c1b23549d3b5a599057e6cf69b..1593ade2a8154da8840236bd9a0debb931ebfa5a 100644
--- a/drivers/clocksource/mmio.c
+++ b/drivers/clocksource/mmio.c
@@ -27,7 +27,7 @@ cycle_t clocksource_mmio_readl_up(struct clocksource *c)
 
 cycle_t clocksource_mmio_readl_down(struct clocksource *c)
 {
-	return ~(cycle_t)readl_relaxed(to_mmio_clksrc(c)->reg);
+	return ~(cycle_t)readl_relaxed(to_mmio_clksrc(c)->reg) & c->mask;
 }
 
 cycle_t clocksource_mmio_readw_up(struct clocksource *c)
@@ -37,7 +37,7 @@ cycle_t clocksource_mmio_readw_up(struct clocksource *c)
 
 cycle_t clocksource_mmio_readw_down(struct clocksource *c)
 {
-	return ~(cycle_t)readw_relaxed(to_mmio_clksrc(c)->reg);
+	return ~(cycle_t)readw_relaxed(to_mmio_clksrc(c)->reg) & c->mask;
 }
 
 /**