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| author | Christoph Hellwig <hch@lst.de> | 2019-10-29 11:01:37 +0100 |
|---|---|---|
| committer | Christoph Hellwig <hch@lst.de> | 2019-11-11 10:52:15 +0100 |
| commit | 34dc0ea6bc960f1f57b2148f01a3f4da23f87013 (patch) | |
| tree | f6d10010989435562d0ece0971ed992febe6c26c /kernel/dma/Kconfig | |
| parent | dma-direct: remove the dma_handle argument to __dma_direct_alloc_pages (diff) | |
| download | linux-34dc0ea6bc960f1f57b2148f01a3f4da23f87013.tar.xz linux-34dc0ea6bc960f1f57b2148f01a3f4da23f87013.zip | |
dma-direct: provide mmap and get_sgtable method overrides
For dma-direct we know that the DMA address is an encoding of the
physical address that we can trivially decode. Use that fact to
provide implementations that do not need the arch_dma_coherent_to_pfn
architecture hook. Note that we still can only support mmap of
non-coherent memory only if the architecture provides a way to set an
uncached bit in the page tables. This must be true for architectures
that use the generic remap helpers, but other architectures can also
manually select it.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Max Filippov <jcmvbkbc@gmail.com>
Diffstat (limited to 'kernel/dma/Kconfig')
| -rw-r--r-- | kernel/dma/Kconfig | 12 |
1 files changed, 9 insertions, 3 deletions
diff --git a/kernel/dma/Kconfig b/kernel/dma/Kconfig index 73c5c2b8e824..4c103a24e380 100644 --- a/kernel/dma/Kconfig +++ b/kernel/dma/Kconfig @@ -51,9 +51,6 @@ config ARCH_HAS_SYNC_DMA_FOR_CPU_ALL config ARCH_HAS_DMA_PREP_COHERENT bool -config ARCH_HAS_DMA_COHERENT_TO_PFN - bool - config ARCH_HAS_FORCE_DMA_UNENCRYPTED bool @@ -68,9 +65,18 @@ config SWIOTLB bool select NEED_DMA_MAP_STATE +# +# Should be selected if we can mmap non-coherent mappings to userspace. +# The only thing that is really required is a way to set an uncached bit +# in the pagetables +# +config DMA_NONCOHERENT_MMAP + bool + config DMA_REMAP depends on MMU select GENERIC_ALLOCATOR + select DMA_NONCOHERENT_MMAP bool config DMA_DIRECT_REMAP |