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DIR:/usr/src/kernels/4.18.0-553.22.1.lve.1.el8.x86_64/kernel/dma/
Current File : //usr/src/kernels/4.18.0-553.22.1.lve.1.el8.x86_64/kernel/dma/Kconfig
config HAS_DMA
	bool
	depends on !NO_DMA
	default y

#
# IOMMU drivers that can bypass the IOMMU code and optionally use the direct
# mapping fast path should select this option and set the dma_ops_bypass
# flag in struct device where applicable
#
config DMA_OPS_BYPASS
	bool

config DMA_OPS
	bool

# Lets platform IOMMU driver choose between bypass and IOMMU
config ARCH_HAS_DMA_MAP_DIRECT
	bool

config NEED_SG_DMA_LENGTH
	bool

config NEED_DMA_MAP_STATE
	bool

config ARCH_DMA_ADDR_T_64BIT
	def_bool 64BIT || PHYS_ADDR_T_64BIT

config ARCH_HAS_DMA_SET_MASK
	bool

#
# Select this option if the architecture needs special handling for
# DMA_ATTR_WRITE_COMBINE.  Normally the "uncached" mapping should be what
# people thing of when saying write combine, so very few platforms should
# need to enable this.
#
config ARCH_HAS_DMA_WRITE_COMBINE
	bool

#
# Select if the architectures provides the arch_dma_mark_clean hook
#
config ARCH_HAS_DMA_MARK_CLEAN
	bool

config HAVE_GENERIC_DMA_COHERENT
	bool

config ARCH_HAS_SETUP_DMA_OPS
	bool

config ARCH_HAS_SYNC_DMA_FOR_DEVICE
	bool

config ARCH_HAS_SYNC_DMA_FOR_CPU
	bool
	select NEED_DMA_MAP_STATE

config ARCH_HAS_SYNC_DMA_FOR_CPU_ALL
	bool

config ARCH_HAS_DMA_PREP_COHERENT
	bool

config ARCH_HAS_FORCE_DMA_UNENCRYPTED
	bool

config DMA_NONCOHERENT_CACHE_SYNC
	bool

config DMA_VIRT_OPS
	bool
	depends on HAS_DMA
	select DMA_OPS

config SWIOTLB
	bool
	select NEED_DMA_MAP_STATE

config DMA_RESTRICTED_POOL
	bool "DMA Restricted Pool"
	depends on OF && OF_RESERVED_MEM && SWIOTLB
	help
	  This enables support for restricted DMA pools which provide a level of
	  DMA memory protection on systems with limited hardware protection
	  capabilities, such as those lacking an IOMMU.

	  For more information see
	  <Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt>
	  and <kernel/dma/swiotlb.c>.
	  If unsure, say "n".

#
# 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
	default y if !MMU
	bool

config DMA_COHERENT_POOL
	select GENERIC_ALLOCATOR
	bool

config DMA_REMAP
	bool
	depends on MMU
	select DMA_NONCOHERENT_MMAP

config DMA_DIRECT_REMAP
	bool
	select DMA_REMAP
	select DMA_COHERENT_POOL

config DMA_API_DEBUG
	bool "Enable debugging of DMA-API usage"
	select NEED_DMA_MAP_STATE
	help
	  Enable this option to debug the use of the DMA API by device drivers.
	  With this option you will be able to detect common bugs in device
	  drivers like double-freeing of DMA mappings or freeing mappings that
	  were never allocated.

	  This option causes a performance degradation.  Use only if you want to
	  debug device drivers and dma interactions.

	  If unsure, say N.

config DMA_API_DEBUG_SG
	bool "Debug DMA scatter-gather usage"
	default y
	depends on DMA_API_DEBUG
	help
	  Perform extra checking that callers of dma_map_sg() have respected the
	  appropriate segment length/boundary limits for the given device when
	  preparing DMA scatterlists.

	  This is particularly likely to have been overlooked in cases where the
	  dma_map_sg() API is used for general bulk mapping of pages rather than
	  preparing literal scatter-gather descriptors, where there is a risk of
	  unexpected behaviour from DMA API implementations if the scatterlist
	  is technically out-of-spec.

	  If unsure, say N.