From e9d709dc7ce4a72ab4c193b008e68829992c54cd Mon Sep 17 00:00:00 2001
From: Joerg Roedel <joro@8bytes.org>
Date: Thu, 18 Apr 2013 17:55:04 +0200
Subject: [PATCH] --- yaml --- r: 373567 b: refs/heads/master c:
 d3263bc29706e42f74d8800807c2dedf320d77f1 h: refs/heads/master i:   373565:
 4146a50875a00c422c2944bd1abbae825fd1fbe3   373563:
 f2eaaac4fd75ada3944b12f70c2d1f8eb1fe8783   373559:
 5900b7e7ae8dd3f7b124a89538e0c78ce97d3a51   373551:
 212879f1c49ed37df1370a5006e0e680f75a732d   373535:
 887dbfcf2fd525c578c3ccc347f254a1ccac96a3   373503:
 74e2e03db4996e478715cbb55d610786a525ba67 v: v3

---
 [refs]                          |  2 +-
 trunk/drivers/iommu/amd_iommu.c | 34 +++++++++++++++++++++++++--------
 2 files changed, 27 insertions(+), 9 deletions(-)

diff --git a/[refs] b/[refs]
index 390661ec1e07..d4555ddb4e2d 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 7d8bfa26f236bc9528415402dda6b498a0682e42
+refs/heads/master: d3263bc29706e42f74d8800807c2dedf320d77f1
diff --git a/trunk/drivers/iommu/amd_iommu.c b/trunk/drivers/iommu/amd_iommu.c
index f42793d1574d..27792f8c429d 100644
--- a/trunk/drivers/iommu/amd_iommu.c
+++ b/trunk/drivers/iommu/amd_iommu.c
@@ -700,14 +700,23 @@ static void iommu_print_event(struct amd_iommu *iommu, void *__evt)
 
 static void iommu_poll_events(struct amd_iommu *iommu)
 {
-	u32 head, tail;
+	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 */
+	do {
+		/*
+		 * Workaround for Erratum ERBT1312
+		 * Clearing the EVT_INT bit may race in the hardware, so read
+		 * it again and make sure it was really cleared
+		 */
+		status = readl(iommu->mmio_base + MMIO_STATUS_OFFSET);
+		writel(MMIO_STATUS_EVT_INT_MASK,
+		       iommu->mmio_base + MMIO_STATUS_OFFSET);
+	} while (status & MMIO_STATUS_EVT_INT_MASK);
+
 	head = readl(iommu->mmio_base + MMIO_EVT_HEAD_OFFSET);
 	tail = readl(iommu->mmio_base + MMIO_EVT_TAIL_OFFSET);
 
@@ -744,16 +753,25 @@ static void iommu_handle_ppr_entry(struct amd_iommu *iommu, u64 *raw)
 static void iommu_poll_ppr_log(struct amd_iommu *iommu)
 {
 	unsigned long flags;
-	u32 head, tail;
+	u32 head, tail, status;
 
 	if (iommu->ppr_log == NULL)
 		return;
 
-	/* enable ppr interrupts again */
-	writel(MMIO_STATUS_PPR_INT_MASK, iommu->mmio_base + MMIO_STATUS_OFFSET);
-
 	spin_lock_irqsave(&iommu->lock, flags);
 
+	/* enable ppr interrupts again */
+	do {
+		/*
+		 * Workaround for Erratum ERBT1312
+		 * Clearing the PPR_INT bit may race in the hardware, so read
+		 * it again and make sure it was really cleared
+		 */
+		status = readl(iommu->mmio_base + MMIO_STATUS_OFFSET);
+		writel(MMIO_STATUS_PPR_INT_MASK,
+		       iommu->mmio_base + MMIO_STATUS_OFFSET);
+	} while (status & MMIO_STATUS_PPR_INT_MASK);
+
 	head = readl(iommu->mmio_base + MMIO_PPR_HEAD_OFFSET);
 	tail = readl(iommu->mmio_base + MMIO_PPR_TAIL_OFFSET);