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

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@amd.com>
Signed-off-by: Joerg Roedel <joro@8bytes.org>

diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
index b287ca33833df792350baad6f82fefbe1494e038..d6433e2a3bb4f972b73ff0cb8c02c4c67866e0a3 100644 (file)
--- 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;
        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 e38ab438bb342e241c1b5e545a0b01a4e4ea5017..083f98c0488b676849e64eaa1006a14b4bab6406 100644 (file)
--- 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)