tty: xuartps: Acquire port lock for shutdown

Shutting down the UART port can happen while console operations are in
progress. Holding the port lock serializes these operations and avoids
the UART HW to be disabled in the middle of console prints.

Signed-off-by: Soren Brinkmann <soren.brinkmann@xilinx.com>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c
index ab3995d00973ac4d45fc405606f9686495e841c4..f3ac69387b0ade41e6aa8d7ecf3b8b0a2bada151 100644 (file)
--- a/drivers/tty/serial/xilinx_uartps.c
+++ b/drivers/tty/serial/xilinx_uartps.c
@@ -826,6 +826,9 @@ static int cdns_uart_startup(struct uart_port *port)
 static void cdns_uart_shutdown(struct uart_port *port)
 {
        int status;
+       unsigned long flags;
+
+       spin_lock_irqsave(&port->lock, flags);
 
        /* Disable interrupts */
        status = readl(port->membase + CDNS_UART_IMR_OFFSET);
@@ -835,6 +838,9 @@ static void cdns_uart_shutdown(struct uart_port *port)
        /* Disable the TX and RX */
        writel(CDNS_UART_CR_TX_DIS | CDNS_UART_CR_RX_DIS,
                        port->membase + CDNS_UART_CR_OFFSET);
+
+       spin_unlock_irqrestore(&port->lock, flags);
+
        free_irq(port->irq, port);
 }