From: Robin Murphy <[email protected]>
commit 1d9777b9f3d55b4b6faf186ba4f1d6fb560c0523 upstream
In certain cases we may want to refuse to allow nested translation even
when both stages are implemented, so let's add an explicit feature for
nesting support which we can control in its own right. For now this
merely serves as documentation, but it means a nice convenient check
will be ready and waiting for the future nesting code.
Signed-off-by: Robin Murphy <[email protected]>
Reviewed-by: Nicolin Chen <[email protected]>
Link: https://lore.kernel.org/r/136c3f4a3a84cc14a5a1978ace57dfd3ed67b688.1683731256.git.robin.murphy@arm.com
Signed-off-by: Will Deacon <[email protected]>
Signed-off-by: Easwar Hariharan <[email protected]>
---
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 4 ++++
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h | 1 +
2 files changed, 5 insertions(+)
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
index 6a551a48d271..7cec4a457d91 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -3703,6 +3703,10 @@ static int arm_smmu_device_hw_probe(struct arm_smmu_device *smmu)
smmu->ias = max(smmu->ias, smmu->oas);
+ if ((smmu->features & ARM_SMMU_FEAT_TRANS_S1) &&
+ (smmu->features & ARM_SMMU_FEAT_TRANS_S2))
+ smmu->features |= ARM_SMMU_FEAT_NESTING;
+
arm_smmu_device_iidr_probe(smmu);
if (arm_smmu_sva_supported(smmu))
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
index abaecdf8d5d2..c594a9b46999 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
@@ -646,6 +646,7 @@ struct arm_smmu_device {
#define ARM_SMMU_FEAT_BTM (1 << 16)
#define ARM_SMMU_FEAT_SVA (1 << 17)
#define ARM_SMMU_FEAT_E2H (1 << 18)
+#define ARM_SMMU_FEAT_NESTING (1 << 19)
u32 features;
#define ARM_SMMU_OPT_SKIP_PREFETCH (1 << 0)
--
2.25.1