From: Ahung Cheng <ahcheng@xxxxxxxxxx> The IER and DLH registers occupy the same address space, selected by the LCR.DLAB bit. Hence, add port lock to protect IER when LCR.DLAB bit is set. Signed-off-by: Ahung Cheng <ahcheng@xxxxxxxxxx> Signed-off-by: Krishna Yarlagadda <kyarlagadda@xxxxxxxxxx> --- drivers/tty/serial/serial-tegra.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/tty/serial/serial-tegra.c b/drivers/tty/serial/serial-tegra.c index d908465..ae7225c 100644 --- a/drivers/tty/serial/serial-tegra.c +++ b/drivers/tty/serial/serial-tegra.c @@ -296,6 +296,7 @@ static int tegra_set_baudrate(struct tegra_uart_port *tup, unsigned int baud) unsigned long rate; unsigned int divisor; unsigned long lcr; + unsigned long flags; int ret; if (tup->current_baud == baud) @@ -315,6 +316,7 @@ static int tegra_set_baudrate(struct tegra_uart_port *tup, unsigned int baud) divisor = DIV_ROUND_CLOSEST(rate, baud * 16); } + spin_lock_irqsave(&tup->uport.lock, flags); lcr = tup->lcr_shadow; lcr |= UART_LCR_DLAB; tegra_uart_write(tup, lcr, UART_LCR); @@ -327,6 +329,7 @@ static int tegra_set_baudrate(struct tegra_uart_port *tup, unsigned int baud) /* Dummy read to ensure the write is posted */ tegra_uart_read(tup, UART_SCR); + spin_unlock_irqrestore(&tup->uport.lock, flags); tup->current_baud = baud; -- 2.7.4
