[PATCH v12 11/17] arm-smmu-v3: Add blocking domain support

[Lu Baolu <baolu.lu@linux.intel.com>]

The ARM SMMUv3 hardwares support blocking DMA transactions by clearing
the translation table entries. This implements a real blocking domain
to avoid using an empty UNMANAGED domain.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Tested-by: Zhangfei Gao <zhangfei.gao@linaro.org>
---
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 20 ++++++++++++++++++++
 1 file changed, 20 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 f88541be8213..5520a9607758 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -88,6 +88,8 @@ static struct arm_smmu_option_prop arm_smmu_options[] = {
 	{ 0, NULL},
 };
 
+static void arm_smmu_detach_dev(struct arm_smmu_master *master);
+
 static void parse_driver_options(struct arm_smmu_device *smmu)
 {
 	int i = 0;
@@ -2004,10 +2006,28 @@ static bool arm_smmu_capable(enum iommu_cap cap)
 	}
 }
 
+static int blocking_domain_attach_dev(struct iommu_domain *domain,
+				      struct device *dev)
+{
+	struct arm_smmu_master *master = dev_iommu_priv_get(dev);
+
+	arm_smmu_detach_dev(master);
+	return 0;
+}
+
+static struct iommu_domain blocking_domain = {
+	.ops = &(const struct iommu_domain_ops) {
+		.attach_dev	= blocking_domain_attach_dev
+	}
+};
+
 static struct iommu_domain *arm_smmu_domain_alloc(unsigned type)
 {
 	struct arm_smmu_domain *smmu_domain;
 
+	if (type == IOMMU_DOMAIN_BLOCKED)
+		return &blocking_domain;
+
 	if (type != IOMMU_DOMAIN_UNMANAGED &&
 	    type != IOMMU_DOMAIN_DMA &&
 	    type != IOMMU_DOMAIN_DMA_FQ &&
-- 
2.25.1