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Commit f1d84548 authored by Robin Murphy's avatar Robin Murphy Committed by Will Deacon
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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: default avatarMitchel Humpherys <mitchelh@codeaurora.org>
Signed-off-by: default avatarRobin Murphy <robin.murphy@arm.com>
[will: added error checking]
Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
parent 4a1c93cb

drivers/iommu/arm-smmu.c

+9 −0
Original line number Diff line number Diff line
@@ -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;