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| author | Robin Murphy <Robin.Murphy@arm.com> | 2015-07-29 19:46:04 +0100 |
|---|---|---|
| committer | Will Deacon <will.deacon@arm.com> | 2015-08-06 14:35:38 +0100 |
| commit | f8d5496131554f61b0fd931fa046f0233fe2aac2 (patch) | |
| tree | f7a7855797693f1a9c101cb4dc4dd234a54d5ce2 /drivers/iommu/Kconfig | |
| parent | 85430968ae72650a63f77f05a29d5c56e41581db (diff) | |
| download | linux-f8d5496131554f61b0fd931fa046f0233fe2aac2.tar.gz | |
iommu/io-pgtable-arm: Allow appropriate DMA API use
Currently, users of the LPAE page table code are (ab)using dma_map_page()
as a means to flush page table updates for non-coherent IOMMUs. Since
from the CPU's point of view, creating IOMMU page tables *is* passing
DMA buffers to a device (the IOMMU's page table walker), there's little
reason not to use the DMA API correctly.
Allow IOMMU drivers to opt into DMA API operations for page table
allocation and updates by providing their appropriate device pointer.
The expectation is that an LPAE IOMMU should have a full view of system
memory, so use streaming mappings to avoid unnecessary pressure on
ZONE_DMA, and treat any DMA translation as a warning sign.
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Diffstat (limited to 'drivers/iommu/Kconfig')
| -rw-r--r-- | drivers/iommu/Kconfig | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig index f1fb1d3ccc56..d77a848d50de 100644 --- a/drivers/iommu/Kconfig +++ b/drivers/iommu/Kconfig @@ -23,7 +23,8 @@ config IOMMU_IO_PGTABLE config IOMMU_IO_PGTABLE_LPAE bool "ARMv7/v8 Long Descriptor Format" select IOMMU_IO_PGTABLE - depends on ARM || ARM64 || COMPILE_TEST + # SWIOTLB guarantees a dma_to_phys() implementation + depends on ARM || ARM64 || (COMPILE_TEST && SWIOTLB) help Enable support for the ARM long descriptor pagetable format. This allocator supports 4K/2M/1G, 16K/32M and 64K/512M page |