[PATCH] sa1111: Prevent deadlock in resume path
Marek Vasut
marek.vasut at gmail.com
Wed May 26 15:11:44 EDT 2010
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 <linux at 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 at diku.dk>
Signed-off-by: Marek Vasut <marek.vasut at gmail.com>
---
arch/arm/common/sa1111.c | 9 +++++++--
1 files changed, 7 insertions(+), 2 deletions(-)
diff --git a/arch/arm/common/sa1111.c b/arch/arm/common/sa1111.c
index a52a27c..6f80665 100644
--- 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);
--
1.7.0
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