serial: imx: use locking to stop concurrent access of UCR1
Several places are accessing the UCR1 register without locking.
This probably will cause a race issue when another thread
is accessing the same register.
Add locking to preventing concurrent access of the UCR1 register.
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 eb2210f..c851247 100644
--- a/drivers/tty/serial/imx.c
+++ b/drivers/tty/serial/imx.c
@@ -731,6 +731,9 @@
static void imx_dma_rxint(struct imx_port *sport)
{
unsigned long temp;
+ unsigned long flags;
+
+ spin_lock_irqsave(&sport->port.lock, flags);
temp = readl(sport->port.membase + USR2);
if ((temp & USR2_RDR) && !sport->dma_is_rxing) {
@@ -744,6 +747,8 @@
/* tell the DMA to receive the data. */
start_rx_dma(sport);
}
+
+ spin_unlock_irqrestore(&sport->port.lock, flags);
}
static irqreturn_t imx_int(int irq, void *dev_id)
@@ -873,6 +878,9 @@
static void imx_rx_dma_done(struct imx_port *sport)
{
unsigned long temp;
+ unsigned long flags;
+
+ spin_lock_irqsave(&sport->port.lock, flags);
/* Enable this interrupt when the RXFIFO is empty. */
temp = readl(sport->port.membase + UCR1);
@@ -884,6 +892,8 @@
/* Is the shutdown waiting for us? */
if (waitqueue_active(&sport->dma_wait))
wake_up(&sport->dma_wait);
+
+ spin_unlock_irqrestore(&sport->port.lock, flags);
}
/*
@@ -1194,9 +1204,11 @@
dmaengine_terminate_all(sport->dma_chan_tx);
dmaengine_terminate_all(sport->dma_chan_rx);
}
+ spin_lock_irqsave(&sport->port.lock, flags);
imx_stop_tx(port);
imx_stop_rx(port);
imx_disable_dma(sport);
+ spin_unlock_irqrestore(&sport->port.lock, flags);
imx_uart_dma_exit(sport);
}