ARM: PL011: Ensure IRQs are disabled in UART interrupt handler

As the DMA support introduces a separate interrupt-time callback, our
interrupt handler will not be the only handler which takes the port
lock, so we need to ensure that IRQs are disabled.  We must use the
_irqsave variant so we don't inadvertently enable interrupts.

Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 3 insertions, 2 deletions

diff --git a/drivers/serial/amba-pl011.c b/drivers/serial/amba-pl011.c
index f9b6b8213e77..f741a8b51400 100644
--- a/drivers/serial/amba-pl011.c
+++ b/drivers/serial/amba-pl011.c
@@ -247,10 +247,11 @@ static void pl011_modem_status(struct uart_amba_port *uap)
 static irqreturn_t pl011_int(int irq, void *dev_id)
 {
         struct uart_amba_port *uap = dev_id;
+        unsigned long flags;
         unsigned int status, pass_counter = AMBA_ISR_PASS_LIMIT;
         int handled = 0;
 
-        spin_lock(&uap->port.lock);
+        spin_lock_irqsave(&uap->port.lock, flags);
 
         status = readw(uap->port.membase + UART011_MIS);
         if (status) {
@@ -275,7 +276,7 @@ static irqreturn_t pl011_int(int irq, void *dev_id)
                 handled = 1;
         }
 
-        spin_unlock(&uap->port.lock);
+        spin_unlock_irqrestore(&uap->port.lock, flags);
 
         return IRQ_RETVAL(handled);
 }