diff --git a/drivers/serial/21285.c b/drivers/serial/21285.c
index f8504b0..33fbda7 100644
--- a/drivers/serial/21285.c
+++ b/drivers/serial/21285.c
@@ -110,7 +110,7 @@
 		port->icount.rx++;
 
 		rxs = *CSR_RXSTAT | RXSTAT_DUMMY_READ;
-		if (rxs & RXSTAT_ANYERR) {
+		if (unlikely(rxs & RXSTAT_ANYERR)) {
 			if (rxs & RXSTAT_PARITY)
 				port->icount.parity++;
 			else if (rxs & RXSTAT_FRAME)