serial: imx: protect Soft Reset of port with lock
Previously Soft Reset (clear of SRST bit in UCR2 register)
of UART in startup is not protected by lock, which may have race
with console_write, as console_write may occur at anytime even
when UART port is shutdown.
To avoid this race, protect Soft reset of UART port with spin_lock.
Signed-off-by: Jiada Wang <jiada_wang@mentor.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
index c8cfa06..38717c7 100644
--- a/drivers/tty/serial/imx.c
+++ b/drivers/tty/serial/imx.c
@@ -1114,6 +1114,12 @@
writel(temp & ~UCR4_DREN, sport->port.membase + UCR4);
+ /* Can we enable the DMA support? */
+ if (is_imx6q_uart(sport) && !uart_console(port) &&
+ !sport->dma_is_inited)
+ imx_uart_dma_init(sport);
+
+ spin_lock_irqsave(&sport->port.lock, flags);
/* Reset fifo's and state machines */
i = 100;
@@ -1124,13 +1130,6 @@
while (!(readl(sport->port.membase + UCR2) & UCR2_SRST) && (--i > 0))
udelay(1);
- /* Can we enable the DMA support? */
- if (is_imx6q_uart(sport) && !uart_console(port) &&
- !sport->dma_is_inited)
- imx_uart_dma_init(sport);
-
- spin_lock_irqsave(&sport->port.lock, flags);
-
/*
* Finally, clear and enable interrupts
*/