serial: imx: Disable irqs before requesting them

Disable interrupts before requesting them in order to fix a kernel oops
after lauching a kernel via kexec.

Tested on a imx6sl-evk board.

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.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 2c90dc31bfaabc0242e168dd688faadadd9f164a..cddf9026a72bc1d7afd25a59701c86fb54f90cce 100644 (file)
--- a/drivers/tty/serial/imx.c
+++ b/drivers/tty/serial/imx.c
@@ -1902,7 +1902,7 @@ static int serial_imx_probe(struct platform_device *pdev)
 {
        struct imx_port *sport;
        void __iomem *base;
-       int ret = 0;
+       int ret = 0, reg;
        struct resource *res;
        int txirq, rxirq, rtsirq;
 
@@ -1957,6 +1957,19 @@ static int serial_imx_probe(struct platform_device *pdev)
 
        sport->port.uartclk = clk_get_rate(sport->clk_per);
 
+       /* For register access, we only need to enable the ipg clock. */
+       ret = clk_prepare_enable(sport->clk_ipg);
+       if (ret)
+               return ret;
+
+       /* Disable interrupts before requesting them */
+       reg = readl_relaxed(sport->port.membase + UCR1);
+       reg &= ~(UCR1_ADEN | UCR1_TRDYEN | UCR1_IDEN | UCR1_RRDYEN |
+                UCR1_TXMPTYEN | UCR1_RTSDEN);
+       writel_relaxed(reg, sport->port.membase + UCR1);
+
+       clk_disable_unprepare(sport->clk_ipg);
+
        /*
         * Allocate the IRQ(s) i.MX1 has three interrupts whereas later
         * chips only have one interrupt.