[PATCH v2 3/6] iommu/arm-smmu: Add a domain attribute to pass the pagetable config

[Jordan Crouse]

The Adreno GPU has the capacity to manage its own pagetables and switch
them dynamically from the hardware. Add a domain attribute for arm-smmu-v2
to get the default pagetable configuration so that the GPU driver can match
the format for its own pagetables.

Signed-off-by: Jordan Crouse <jcrouse at codeaurora.org>
---

 drivers/iommu/arm-smmu.c | 12 ++++++++++++
 include/linux/iommu.h    |  1 +
 2 files changed, 13 insertions(+)

diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
index ce6d654301bf..4bd247dfd703 100644
--- a/drivers/iommu/arm-smmu.c
+++ b/drivers/iommu/arm-smmu.c
@@ -1714,6 +1714,18 @@ static int arm_smmu_domain_get_attr(struct iommu_domain *domain,
 		case DOMAIN_ATTR_NESTING:
 			*(int *)data = (smmu_domain->stage == ARM_SMMU_DOMAIN_NESTED);
 			return 0;
+		case DOMAIN_ATTR_PGTABLE_CFG: {
+			struct io_pgtable *pgtable;
+			struct io_pgtable_cfg *dest = data;
+
+			if (!smmu_domain->pgtbl_ops)
+				return -ENODEV;
+
+			pgtable = io_pgtable_ops_to_pgtable(smmu_domain->pgtbl_ops);
+
+			memcpy(dest, &pgtable->cfg, sizeof(*dest));
+			return 0;
+		}
 		default:
 			return -ENODEV;
 		}
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 5f0b7859d2eb..2388117641f1 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -124,6 +124,7 @@ enum iommu_attr {
 	DOMAIN_ATTR_FSL_PAMUV1,
 	DOMAIN_ATTR_NESTING,	/* two stages of translation */
 	DOMAIN_ATTR_DMA_USE_FLUSH_QUEUE,
+	DOMAIN_ATTR_PGTABLE_CFG,
 	DOMAIN_ATTR_MAX,
 };
 
-- 
2.17.1