| Date | Thu, 01 Jul 2010 10:43:19 -0700 | From | Greg KH <> | Subject | [109/200] ARM: 6146/1: sa1111: Prevent deadlock in resume path |
| |
2.6.34-stable review patch. If anyone has any objections, please let me know.
------------------
From: =?UTF-8?q?Marek=20Va=C5=A1ut?= <marek.vasut@gmail.com>
commit 3defb2476166445982a90c12d33f8947e75476c4 upstream.
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> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- arch/arm/common/sa1111.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-)
--- a/arch/arm/common/sa1111.c +++ b/arch/arm/common/sa1111.c @@ -951,8 +951,6 @@ static int sa1111_resume(struct platform 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 * 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);
|