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serial: imx: use locking to stop concurrent access of UCR1

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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>
This commit is contained in:
Jiada Wang 2014-12-09 18:11:23 +09:00 committed by Greg Kroah-Hartman
parent 55d8693acd
commit 73631813c1
1 changed files with 12 additions and 0 deletions
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12
drivers/tty/serial/imx.c
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@ -731,6 +731,9 @@ static int start_rx_dma(struct imx_port *sport);
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 @@ static void imx_dma_rxint(struct imx_port *sport)
/* 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 int imx_setup_ufcr(struct imx_port *sport, unsigned int mode)
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 @@ static void imx_rx_dma_done(struct imx_port *sport)
/* 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 @@ static void imx_shutdown(struct uart_port *port)
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);
}