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_w...@mentor.com>
---
drivers/tty/serial/imx.c | 13 ++++++-------
1 file changed, 6 insertions(+), 7 deletions(-)
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 @@ static int imx_startup(struct uart_port *port)
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 @@ static int imx_startup(struct uart_port *port)
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
*/
--
1.9.3
--
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