[PATCH] iommu: arm-smmu: Fix Tegra workaround for PAGE_SIZE mappings

Ashish Mhetre amhetre at nvidia.com
Wed Jul 17 00:21:45 PDT 2024


PAGE_SIZE can be 16KB for Tegra which is not supported by MMU-500 on
both Tegra194 and Tegra234. So, use 4KB mappings when PAGE_SIZE is 16KB.

Signed-off-by: Ashish Mhetre <amhetre at nvidia.com>
---
 drivers/iommu/arm/arm-smmu/arm-smmu-nvidia.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu-nvidia.c b/drivers/iommu/arm/arm-smmu/arm-smmu-nvidia.c
index 4b2994b6126d..bb621a94f6fe 100644
--- a/drivers/iommu/arm/arm-smmu/arm-smmu-nvidia.c
+++ b/drivers/iommu/arm/arm-smmu/arm-smmu-nvidia.c
@@ -273,11 +273,12 @@ static int nvidia_smmu_init_context(struct arm_smmu_domain *smmu_domain,
 	 * release of PMD entry and avoid translations seeing stale PMD entry in
 	 * walk cache.
 	 * Fix this by limiting the page mappings to PAGE_SIZE on Tegra194 and
-	 * Tegra234.
+	 * Tegra234. Use 4K page mappings if PAGE_SIZE is 16K as MMU500 doesn't
+	 * support it.
 	 */
 	if (of_device_is_compatible(np, "nvidia,tegra234-smmu") ||
 	    of_device_is_compatible(np, "nvidia,tegra194-smmu")) {
-		smmu->pgsize_bitmap = PAGE_SIZE;
+		smmu->pgsize_bitmap = (PAGE_SIZE == SZ_16K) ? SZ_4K : PAGE_SIZE;
 		pgtbl_cfg->pgsize_bitmap = smmu->pgsize_bitmap;
 	}
 
-- 
2.25.1




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