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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>
This commit is contained in:
Jiada Wang 2015-04-13 18:31:43 +09:00 committed by Greg Kroah-Hartman
parent 1e84d22322
commit 5379418322
1 changed files with 6 additions and 7 deletions
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13
drivers/tty/serial/imx.c
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@ -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
*/