From c1b29ef10efcb357a6f77ab55e81e79025049b1b Mon Sep 17 00:00:00 2001
From: Patrick Daly <pdaly@codeaurora.org>
Date: Tue, 15 Mar 2016 18:58:28 -0700
Subject: [PATCH] iommu/arm-smmu: Support DOMAIN_ATTR_S1_BYPASS

Certain configurations may require nested translation, but may
want to avoid software performance limitation on map/unmap
operations.

Change-Id: I6653b3b6ceb071283fb5a8e07257c496e99dd1f3
Signed-off-by: Patrick Daly <pdaly@codeaurora.org>
---
 drivers/iommu/arm-smmu.c | 21 ++++++++++++++++++++-
 1 file changed, 20 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
index b2c53de88b03..9552e5b6a3d1 100644
--- a/drivers/iommu/arm-smmu.c
+++ b/drivers/iommu/arm-smmu.c
@@ -1453,7 +1453,9 @@ static void arm_smmu_init_context_bank(struct arm_smmu_domain *smmu_domain,
 	}
 
 	/* SCTLR */
-	reg = SCTLR_CFCFG | SCTLR_CFIE | SCTLR_CFRE | SCTLR_M | SCTLR_EAE_SBOP;
+	reg = SCTLR_CFCFG | SCTLR_CFIE | SCTLR_CFRE | SCTLR_EAE_SBOP;
+	if (!stage1 || !(smmu_domain->attributes & DOMAIN_ATTR_S1_BYPASS))
+		reg |= SCTLR_M;
 	if (stage1)
 		reg |= SCTLR_S1_ASIDPNE;
 #ifdef __BIG_ENDIAN
@@ -2898,6 +2900,11 @@ static int arm_smmu_domain_get_attr(struct iommu_domain *domain,
 				    & (1 << DOMAIN_ATTR_NON_FATAL_FAULTS));
 		ret = 0;
 		break;
+	case DOMAIN_ATTR_S1_BYPASS:
+		*((int *)data) = !!(smmu_domain->attributes
+				    & (1 << DOMAIN_ATTR_S1_BYPASS));
+		ret = 0;
+		break;
 	default:
 		ret = -ENODEV;
 		break;
@@ -3009,6 +3016,18 @@ static int arm_smmu_domain_set_attr(struct iommu_domain *domain,
 		smmu_domain->non_fatal_faults = *((int *)data);
 		ret = 0;
 		break;
+	case DOMAIN_ATTR_S1_BYPASS: {
+		int bypass = *((int *)data);
+
+		if (bypass)
+			smmu_domain->attributes |= 1 << DOMAIN_ATTR_S1_BYPASS;
+		else
+			smmu_domain->attributes &=
+					~(1 << DOMAIN_ATTR_S1_BYPASS);
+
+		ret = 0;
+		break;
+	}
 	default:
 		ret = -ENODEV;
 		break;