From: Jiada Wang Date: Mon, 13 Apr 2015 09:31:43 +0000 (+0900) Subject: serial: imx: protect Soft Reset of port with lock X-Git-Url: http://git.cdn.openwrt.org/?a=commitdiff_plain;h=53794183225f25830ab40e1c83ae885f11501784;p=openwrt%2Fstaging%2Fblogic.git 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 Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c index c8cfa0637128..38717c7bb46f 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 */