[ 3.5.y.z extended stable ] Patch "iommu/amd: Re-enable IOMMU event log interrupt after" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    iommu/amd: Re-enable IOMMU event log interrupt after

to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.5.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From 40d3b70763efb621cc0e142c71c0cf6d4ba4c237 Mon Sep 17 00:00:00 2001
From: Suravee Suthikulpanit <suravee.suthikulpanit at amd.com>
Date: Wed, 27 Mar 2013 18:51:52 -0500
Subject: [PATCH] iommu/amd: Re-enable IOMMU event log interrupt after
 handling.

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 at amd.com>
Signed-off-by: Joerg Roedel <joro at 8bytes.org>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/iommu/amd_iommu.c       | 3 +++
 drivers/iommu/amd_iommu_types.h | 1 +
 2 files changed, 4 insertions(+)

diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
index 33fee0a..257ab08 100644
--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -534,6 +534,9 @@ static void iommu_poll_events(struct amd_iommu *iommu)
 	u32 head, tail;
 	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);

 	head = readl(iommu->mmio_base + MMIO_EVT_HEAD_OFFSET);
diff --git a/drivers/iommu/amd_iommu_types.h b/drivers/iommu/amd_iommu_types.h
index c1b1d48..f9addfd 100644
--- a/drivers/iommu/amd_iommu_types.h
+++ b/drivers/iommu/amd_iommu_types.h
@@ -99,6 +99,7 @@
 #define PASID_MASK		0x000fffff

 /* MMIO status bits */
+#define MMIO_STATUS_EVT_INT_MASK	(1 << 1)
 #define MMIO_STATUS_COM_WAIT_INT_MASK	(1 << 2)
 #define MMIO_STATUS_PPR_INT_MASK	(1 << 6)

--
1.8.1.2