[PATCH 1/4] serial: fsl_lpuart: delete timer on shutdown

[Stefan Agner]

If the serial port gets closed while a RX transfer is in progress,
the timer might fire after the serial port shutdown finished.
Setup the timer on UART startup which allows to delete the timer
unconditionally on shutdown. This also saves the initialization
on each transfer too.

Signed-off-by: Stefan Agner <stefan at agner.ch>
---
 drivers/tty/serial/fsl_lpuart.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c
index 6dd53af..b1905a9 100644
--- a/drivers/tty/serial/fsl_lpuart.c
+++ b/drivers/tty/serial/fsl_lpuart.c
@@ -506,9 +506,6 @@ static inline void lpuart_prepare_rx(struct lpuart_port *sport)
 
 	spin_lock_irqsave(&sport->port.lock, flags);
 
-	init_timer(&sport->lpuart_timer);
-	sport->lpuart_timer.function = lpuart_timer_func;
-	sport->lpuart_timer.data = (unsigned long)sport;
 	sport->lpuart_timer.expires = jiffies + sport->dma_rx_timeout;
 	add_timer(&sport->lpuart_timer);
 
@@ -1106,6 +1103,8 @@ static int lpuart_startup(struct uart_port *port)
 		sport->lpuart_dma_use = false;
 	} else {
 		sport->lpuart_dma_use = true;
+		setup_timer(&sport->lpuart_timer, lpuart_timer_func,
+			    (unsigned long)sport);
 		temp = readb(port->membase + UARTCR5);
 		writeb(temp | UARTCR5_TDMAS, port->membase + UARTCR5);
 	}
@@ -1180,6 +1179,8 @@ static void lpuart_shutdown(struct uart_port *port)
 	devm_free_irq(port->dev, port->irq, sport);
 
 	if (sport->lpuart_dma_use) {
+		del_timer_sync(&sport->lpuart_timer);
+
 		lpuart_dma_tx_free(port);
 		lpuart_dma_rx_free(port);
 	}
-- 
2.1.3