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path: root/drivers/iommu/amd_iommu.c
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Diffstat (limited to 'drivers/iommu/amd_iommu.c')
-rw-r--r--drivers/iommu/amd_iommu.c34
1 files changed, 26 insertions, 8 deletions
diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
index 48f416aca05..99a8444fc68 100644
--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -531,14 +531,23 @@ retry:
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);
@@ -575,16 +584,25 @@ 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);