[PATCHv3 3/7] iommu/arm-smmu: Add domain attribute for system cache

[Sai Prakash Ranjan]

Add iommu domain attribute for using system cache aka last level
cache by client drivers like GPU to set right attributes for caching
the hardware pagetables into the system cache.

Signed-off-by: Sai Prakash Ranjan <saiprakash.ranjan@xxxxxxxxxxxxxx>
---
 drivers/iommu/arm-smmu.c | 17 +++++++++++++++++
 drivers/iommu/arm-smmu.h |  1 +
 include/linux/iommu.h    |  1 +
 3 files changed, 19 insertions(+)

diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
index b2564f93d685..71b6f7038423 100644
--- a/drivers/iommu/arm-smmu.c
+++ b/drivers/iommu/arm-smmu.c
@@ -897,6 +897,9 @@ static int arm_smmu_init_domain_context(struct iommu_domain *domain,
 			goto out_unlock;
 	}
 
+	if (smmu_domain->sys_cache)
+		pgtbl_cfg.quirks |= IO_PGTABLE_QUIRK_SYS_CACHE;
+
 	if (smmu_domain->non_strict)
 		pgtbl_cfg.quirks |= IO_PGTABLE_QUIRK_NON_STRICT;
 
@@ -1732,6 +1735,9 @@ static int arm_smmu_domain_get_attr(struct iommu_domain *domain,
 		case DOMAIN_ATTR_DMA_USE_FLUSH_QUEUE:
 			*(int *)data = smmu_domain->non_strict;
 			return 0;
+		case DOMAIN_ATTR_SYS_CACHE:
+			*((int *)data) = smmu_domain->sys_cache;
+			return 0;
 		default:
 			return -ENODEV;
 		}
@@ -1763,6 +1769,17 @@ static int arm_smmu_domain_set_attr(struct iommu_domain *domain,
 			else
 				smmu_domain->stage = ARM_SMMU_DOMAIN_S1;
 			break;
+		case DOMAIN_ATTR_SYS_CACHE:
+			if (smmu_domain->smmu) {
+				ret = -EPERM;
+				goto out_unlock;
+			}
+
+			if (*((int *)data))
+				smmu_domain->sys_cache = true;
+			else
+				smmu_domain->sys_cache = false;
+			break;
 		default:
 			ret = -ENODEV;
 		}
diff --git a/drivers/iommu/arm-smmu.h b/drivers/iommu/arm-smmu.h
index 4a335ef3d97a..bbae48bdc022 100644
--- a/drivers/iommu/arm-smmu.h
+++ b/drivers/iommu/arm-smmu.h
@@ -348,6 +348,7 @@ struct arm_smmu_domain {
 	struct iommu_domain		domain;
 	struct device			*dev;	/* Device attached to this domain */
 	bool				aux;
+	bool				sys_cache;
 };
 
 struct arm_smmu_cb {
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 2388117641f1..a48edbebe3cb 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -125,6 +125,7 @@ enum iommu_attr {
 	DOMAIN_ATTR_NESTING,	/* two stages of translation */
 	DOMAIN_ATTR_DMA_USE_FLUSH_QUEUE,
 	DOMAIN_ATTR_PGTABLE_CFG,
+	DOMAIN_ATTR_SYS_CACHE,
 	DOMAIN_ATTR_MAX,
 };
 
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