[PATCH v3 09/12] iommu/arm-smmu-v3: Realize switch_dirty_log iommu ops

[Keqian Zhu <zhukeqian1@huawei.com>]

From: Kunkun Jiang <jiangkunkun@huawei.com>

This realizes switch_dirty_log by invoking iommu_split_block() and
iommu_merge_page(). HTTU HD feature is required.

Co-developed-by: Keqian Zhu <zhukeqian1@huawei.com>
Signed-off-by: Kunkun Jiang <jiangkunkun@huawei.com>
---
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 38 +++++++++++++++++++++
 1 file changed, 38 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 4d8495d88be2..52c6f3e74d6f 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -2590,6 +2590,43 @@ static int arm_smmu_merge_page(struct iommu_domain *domain,
 	return 0;
 }
 
+static int arm_smmu_switch_dirty_log(struct iommu_domain *domain, bool enable,
+				     unsigned long iova, size_t size, int prot)
+{
+	struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
+	struct arm_smmu_device *smmu = smmu_domain->smmu;
+
+	if (!(smmu->features & ARM_SMMU_FEAT_HD))
+		return -ENODEV;
+	if (smmu_domain->stage != ARM_SMMU_DOMAIN_S1)
+		return -EINVAL;
+
+	if (enable) {
+		/*
+		 * For SMMU, the hardware dirty management is always enabled if
+		 * hardware supports HTTU HD. The action to start dirty log is
+		 * spliting block mapping.
+		 *
+		 * We don't return error even if the split operation fail, as we
+		 * can still track dirty at block granule, which is still a much
+		 * better choice compared to full dirty policy.
+		 */
+		iommu_split_block(domain, iova, size);
+	} else {
+		/*
+		 * For SMMU, the hardware dirty management is always enabled if
+		 * hardware supports HTTU HD. The action to start dirty log is
+		 * merging page mapping.
+		 *
+		 * We don't return error even if the merge operation fail, as it
+		 * just effects performace of DMA transaction.
+		 */
+		iommu_merge_page(domain, iova, size, prot);
+	}
+
+	return 0;
+}
+
 static int arm_smmu_of_xlate(struct device *dev, struct of_phandle_args *args)
 {
 	return iommu_fwspec_add_ids(dev, args->args, 1);
@@ -2691,6 +2728,7 @@ static struct iommu_ops arm_smmu_ops = {
 	.domain_set_attr	= arm_smmu_domain_set_attr,
 	.split_block		= arm_smmu_split_block,
 	.merge_page		= arm_smmu_merge_page,
+	.switch_dirty_log	= arm_smmu_switch_dirty_log,
 	.of_xlate		= arm_smmu_of_xlate,
 	.get_resv_regions	= arm_smmu_get_resv_regions,
 	.put_resv_regions	= generic_iommu_put_resv_regions,
-- 
2.19.1

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