[PATCH 030/105] iommu/amd: Re-enable IOMMU event log interrupt after handling.

[Kamal Mostafa]

3.8.13.4 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Suravee Suthikulpanit <suravee.suthikulpanit@xxxxxxx>

commit 925fe08bce38d1ff052fe2209b9e2b8d5fbb7f98 upstream.

Current driver does not clear the IOMMU event log interrupt bit
in the IOMMU status register after processing an interrupt.
This causes the IOMMU hardware to generate event log interrupt only once.
This has been observed in both IOMMU v1 and V2 hardware.
This patch clears the bit by writing 1 to bit 1 of the IOMMU
status register (MMIO Offset 2020h)

Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@xxxxxxx>
Signed-off-by: Joerg Roedel <joro@xxxxxxxxxx>
Signed-off-by: Kamal Mostafa <kamal@xxxxxxxxxxxxx>
---
 drivers/iommu/amd_iommu.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
index 6202782..409b171 100644
--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -703,6 +703,9 @@ static void iommu_poll_events(struct amd_iommu *iommu)
 	u32 head, tail, status;
 	unsigned long flags;
 
+	/* enable event interrupts again */
+	writel(MMIO_STATUS_EVT_INT_MASK, iommu->mmio_base + MMIO_STATUS_OFFSET);
+
 	spin_lock_irqsave(&iommu->lock, flags);
 
 	/* enable event interrupts again */
-- 
1.8.1.2

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