On 7/23/2024 9:41 PM, Will Deacon wrote:
External email: Use caution opening links or attachments On Wed, Jul 17, 2024 at 07:21:45AM +0000, Ashish Mhetre wrote: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@xxxxxxxxxx> --- 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;Perhaps it would be more robust to do a read-modify-write of the pgsize_bitmap, preserving all the page-sizes that are <= PAGE_SIZE (i.e. and it with something like GENMASK(PAGE_SHIFT, 0)? Will
Thanks for the review Will. Yes, that will be a better approach as pgsize_bitmap will never be with 16K granularity for Tegra. I will send new version with this update.
