[RFC PATCH 08/11] iommu/arm-smmu-v3: Add HWDBM device feature reporting

[Keqian Zhu]

From: jiangkunkun <jiangkunkun at huawei.com>

We have implemented these interfaces required to support iommu
dirty log tracking. The last step is reporting this feature to
upper user, then the user can perform higher policy base on it.
This adds a new dev feature named IOMMU_DEV_FEAT_HWDBM in iommu
layer. For arm smmuv3, it is equal to ARM_SMMU_FEAT_HTTU_HD.

Co-developed-by: Keqian Zhu <zhukeqian1 at huawei.com>
Signed-off-by: Kunkun Jiang <jiangkunkun at huawei.com>
---
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 2 ++
 include/linux/iommu.h                       | 1 +
 2 files changed, 3 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 0c24503d29d3..cbde0489cf31 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -2629,6 +2629,8 @@ static bool arm_smmu_dev_has_feature(struct device *dev,
 	switch (feat) {
 	case IOMMU_DEV_FEAT_SVA:
 		return arm_smmu_master_sva_supported(master);
+	case IOMMU_DEV_FEAT_HWDBM:
+		return !!(master->smmu->features & ARM_SMMU_FEAT_HTTU_HD);
 	default:
 		return false;
 	}
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 1cb6cd0cfc7b..77e561ed57fd 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -160,6 +160,7 @@ struct iommu_resv_region {
 enum iommu_dev_features {
 	IOMMU_DEV_FEAT_AUX,	/* Aux-domain feature */
 	IOMMU_DEV_FEAT_SVA,	/* Shared Virtual Addresses */
+	IOMMU_DEV_FEAT_HWDBM,	/* Hardware Dirty Bit Management */
 };
 
 #define IOMMU_PASID_INVALID	(-1U)
-- 
2.19.1