diff --git a/drivers/tty/serial/pch_uart.c b/drivers/tty/serial/pch_uart.c
index a8b6759140dd7..317067184bfa4 100644
--- a/drivers/tty/serial/pch_uart.c
+++ b/drivers/tty/serial/pch_uart.c
@@ -776,7 +776,7 @@ static void pch_dma_tx_complete(void *arg)
 	}
 	xmit->tail &= UART_XMIT_SIZE - 1;
 	async_tx_ack(priv->desc_tx);
-	dma_unmap_sg(port->dev, sg, priv->orig_nent, DMA_TO_DEVICE);
+	dma_unmap_sg(port->dev, priv->sg_tx_p, priv->orig_nent, DMA_TO_DEVICE);
 	priv->tx_dma_use = 0;
 	priv->nent = 0;
 	priv->orig_nent = 0;