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Diffstat (limited to 'drivers/iommu/arm-smmu-v3.c')
-rw-r--r--drivers/iommu/arm-smmu-v3.c8
1 files changed, 7 insertions, 1 deletions
diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c
index fc6eb752ab35..eb9937225d64 100644
--- a/drivers/iommu/arm-smmu-v3.c
+++ b/drivers/iommu/arm-smmu-v3.c
@@ -683,7 +683,13 @@ static void queue_inc_cons(struct arm_smmu_queue *q)
u32 cons = (Q_WRP(q, q->cons) | Q_IDX(q, q->cons)) + 1;
q->cons = Q_OVF(q, q->cons) | Q_WRP(q, cons) | Q_IDX(q, cons);
- writel(q->cons, q->cons_reg);
+
+ /*
+ * Ensure that all CPU accesses (reads and writes) to the queue
+ * are complete before we update the cons pointer.
+ */
+ mb();
+ writel_relaxed(q->cons, q->cons_reg);
}
static int queue_sync_prod(struct arm_smmu_queue *q)