From: Robin Murphy Date: Wed, 4 Mar 2015 16:41:05 +0000 (+0000) Subject: iommu/arm-smmu: set a more appropriate DMA mask X-Git-Url: http://git.efficios.com/?a=commitdiff_plain;h=f1d84548694fe45f3348c0379d7277fed05bbcf0;p=deliverable%2Flinux.git iommu/arm-smmu: set a more appropriate DMA mask Since we use dma_map_page() as an architecture-independent means of making page table updates visible to non-coherent SMMUs, we need to have a suitable DMA mask set to discourage the DMA mapping layer from creating bounce buffers and flushing those instead, if said page tables happen to lie outside the default 32-bit mask. Tested-by: Mitchel Humpherys Signed-off-by: Robin Murphy [will: added error checking] Signed-off-by: Will Deacon --- diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c index 4abb831e24f0..161dd46999e2 100644 --- a/drivers/iommu/arm-smmu.c +++ b/drivers/iommu/arm-smmu.c @@ -1634,6 +1634,15 @@ static int arm_smmu_device_cfg_probe(struct arm_smmu_device *smmu) size = arm_smmu_id_size_to_bits((id >> ID2_OAS_SHIFT) & ID2_OAS_MASK); smmu->pa_size = size; + /* + * What the page table walker can address actually depends on which + * descriptor format is in use, but since a) we don't know that yet, + * and b) it can vary per context bank, this will have to do... + */ + if (dma_set_mask_and_coherent(smmu->dev, DMA_BIT_MASK(size))) + dev_warn(smmu->dev, + "failed to set DMA mask for table walker\n"); + if (smmu->version == ARM_SMMU_V1) { smmu->va_size = smmu->ipa_size; size = SZ_4K | SZ_2M | SZ_1G;