[PATCH 3/5] iommu/arm-smmu: caps: add IOMMU_CAP_INTR_REMAP capability

[Will Deacon]

MSIs are just seen as bog standard memory writes by the ARM SMMU, so
they can be translated (and isolated) in the same way.

This patch adds the IOMMU_CAP_INTR_REMAP capability to the ARM SMMU
driver and reworks our capabaility code so that we don't assume the
caps are organised as bits in a bitmask (since this isn't the intention).

Signed-off-by: Will Deacon <will.deacon at arm.com>
---
 drivers/iommu/arm-smmu.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
index e4eebc50612c..835d01f47302 100644
--- a/drivers/iommu/arm-smmu.c
+++ b/drivers/iommu/arm-smmu.c
@@ -1606,13 +1606,17 @@ static phys_addr_t arm_smmu_iova_to_phys(struct iommu_domain *domain,
 static int arm_smmu_domain_has_cap(struct iommu_domain *domain,
 				   unsigned long cap)
 {
-	unsigned long caps = 0;
 	struct arm_smmu_domain *smmu_domain = domain->priv;
+	u32 features = smmu_domain->root_cfg.smmu->features;
 
-	if (smmu_domain->root_cfg.smmu->features & ARM_SMMU_FEAT_COHERENT_WALK)
-		caps |= IOMMU_CAP_CACHE_COHERENCY;
-
-	return !!(cap & caps);
+	switch (cap) {
+	case IOMMU_CAP_CACHE_COHERENCY:
+		return features & ARM_SMMU_FEAT_COHERENT_WALK;
+	case IOMMU_CAP_INTR_REMAP:
+		return 1; /* MSIs are just memory writes */
+	default:
+		return 0;
+	}
 }
 
 static int __arm_smmu_get_pci_sid(struct pci_dev *pdev, u16 alias, void *data)
-- 
2.0.0