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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: Mitchel Humpherys <mitchelh@codeaurora.org>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
[will: added error checking]
Signed-off-by: Will Deacon <will.deacon@arm.com>
This commit is contained in:
Robin Murphy 2015-03-04 16:41:05 +00:00 committed by Will Deacon
parent 4a1c93cbe9
commit f1d8454869
1 changed files with 9 additions and 0 deletions
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9
drivers/iommu/arm-smmu.c
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@ -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;