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Diffstat (limited to 'arch/arm64/Kconfig')
| -rw-r--r-- | arch/arm64/Kconfig | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 7a59117a2bd9..3aa5028607ae 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -156,6 +156,32 @@ config NEED_DMA_MAP_STATE config NEED_SG_DMA_LENGTH def_bool y +config ARM64_DMA_USE_IOMMU + bool + select ARM_HAS_SG_CHAIN + select NEED_SG_DMA_LENGTH + +if ARM64_DMA_USE_IOMMU + +config ARM64_DMA_IOMMU_ALIGNMENT + int "Maximum PAGE_SIZE order of alignment for DMA IOMMU buffers" + range 4 9 + default 8 + help + DMA mapping framework by default aligns all buffers to the smallest + PAGE_SIZE order which is greater than or equal to the requested buffer + size. This works well for buffers up to a few hundreds kilobytes, but + for larger buffers it just a waste of address space. Drivers which has + relatively small addressing window (like 64Mib) might run out of + virtual space with just a few allocations. + + With this parameter you can specify the maximum PAGE_SIZE order for + DMA IOMMU buffers. Larger buffers will be aligned only to this + specified order. The order is expressed as a power of two multiplied + by the PAGE_SIZE. + +endif + config SMP def_bool y |