diff mbox series

[v2,1/5] serial: imx: get rid of unbounded busy-waiting loop

Message ID 1567017475-11919-2-git-send-email-sorganov@gmail.com (mailing list archive)
State Mainlined
Commit 2eda5345e4ef61b35101b4fef58417a41d8d53fd
Headers show
Series Serial: imx: various fixes | expand

Commit Message

Sergey Organov Aug. 28, 2019, 6:37 p.m. UTC 
imx_set_termios(): remove busy-waiting "drain Tx FIFO" loop. Worse
yet, it was potentially unbounded wait due to RTS/CTS (hardware)
handshake.

Let user space ensure draining is done before termios change, if
draining is needed in the first place.

Signed-off-by: Sergey Organov <sorganov@gmail.com>
---
 drivers/tty/serial/imx.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)
diff mbox series

Patch

diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
index d9a73c7..47b6156 100644
--- a/drivers/tty/serial/imx.c
+++ b/drivers/tty/serial/imx.c
@@ -1644,7 +1644,7 @@  imx_uart_set_termios(struct uart_port *port, struct ktermios *termios,
 	uart_update_timeout(port, termios->c_cflag, baud);
 
 	/*
-	 * disable interrupts and drain transmitter
+	 * disable interrupts
 	 */
 	old_ucr1 = imx_uart_readl(sport, UCR1);
 	imx_uart_writel(sport,
@@ -1652,9 +1652,6 @@  imx_uart_set_termios(struct uart_port *port, struct ktermios *termios,
 			UCR1);
 	imx_uart_writel(sport, old_ucr2 & ~UCR2_ATEN, UCR2);
 
-	while (!(imx_uart_readl(sport, USR2) & USR2_TXDC))
-		barrier();
-
 	/* then, disable everything */
 	imx_uart_writel(sport, old_ucr2 & ~(UCR2_TXEN | UCR2_RXEN | UCR2_ATEN), UCR2);