ARM: 6146/1: sa1111: Prevent deadlock in resume path

This patch reorganises the sa1111_resume() function in a manner the spinlock
happens after calling the sa1111_wake(). This fixes two bugs:

1) This function called sa1111_wake() which tried to claim the same spinlock
   the sa1111_resume() already claimed. This would result in certain deadlock.

   Original idea for this part: Russell King <rmk+kernel@arm.linux.org.uk>

2) The function didn't unlock the spinlock in case the chip didn't report
   correct ID.

   Original idea for this part: Julia Lawall <julia@diku.dk>

Signed-off-by: Marek Vasut <marek.vasut@gmail.com>
Cc: <stable@kernel.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

diff --git a/arch/arm/common/sa1111.c b/arch/arm/common/sa1111.c
index a52a27c..6f80665 100644 (file)
--- a/arch/arm/common/sa1111.c
+++ b/arch/arm/common/sa1111.c
@@ -951,8 +951,6 @@ static int sa1111_resume(struct platform_device *dev)
        if (!save)
                return 0;
 
-       spin_lock_irqsave(&sachip->lock, flags);
-
        /*
         * Ensure that the SA1111 is still here.
         * FIXME: shouldn't do this here.
@@ -969,6 +967,13 @@ static int sa1111_resume(struct platform_device *dev)
         * First of all, wake up the chip.
         */
        sa1111_wake(sachip);
+
+       /*
+        * Only lock for write ops. Also, sa1111_wake must be called with
+        * released spinlock!
+        */
+       spin_lock_irqsave(&sachip->lock, flags);
+
        sa1111_writel(0, sachip->base + SA1111_INTC + SA1111_INTEN0);
        sa1111_writel(0, sachip->base + SA1111_INTC + SA1111_INTEN1);