Revert "serial: imx: drop useless member from driver data"

This reverts commit 64432a855148fd858e228a0faaebe7036a549706.

1 files changed, 12 insertions, 1 deletions

diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
index 18154be26855..3b971fa6fba3 100644
--- a/drivers/tty/serial/imx.c
+++ b/drivers/tty/serial/imx.c
@@ -227,6 +227,7 @@ struct imx_port {
 	dma_cookie_t		rx_cookie;
 	unsigned int		tx_bytes;
 	unsigned int		dma_tx_nents;
+	wait_queue_head_t	dma_wait;
 	unsigned int            saved_reg[10];
 	bool			context_saved;
 };
@@ -505,12 +506,20 @@ static void dma_tx_callback(void *data)
 
 	sport->dma_is_txing = 0;
 
+	spin_unlock_irqrestore(&sport->port.lock, flags);
+
 	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
 		uart_write_wakeup(&sport->port);
 
+	if (waitqueue_active(&sport->dma_wait)) {
+		wake_up(&sport->dma_wait);
+		dev_dbg(sport->port.dev, "exit in %s.\n", __func__);
+		return;
+	}
+
+	spin_lock_irqsave(&sport->port.lock, flags);
 	if (!uart_circ_empty(xmit) && !uart_tx_stopped(&sport->port))
 		imx_dma_tx(sport);
-
 	spin_unlock_irqrestore(&sport->port.lock, flags);
 }
 
@@ -1207,6 +1216,8 @@ static void imx_enable_dma(struct imx_port *sport)
 {
 	unsigned long temp;
 
+	init_waitqueue_head(&sport->dma_wait);
+
 	/* set UCR1 */
 	temp = readl(sport->port.membase + UCR1);
 	temp |= UCR1_RDMAEN | UCR1_TDMAEN | UCR1_ATDMAEN;