0001 # SPDX-License-Identifier: GPL-2.0-only
0002
0003 config NO_DMA
0004 bool
0005
0006 config HAS_DMA
0007 bool
0008 depends on !NO_DMA
0009 default y
0010
0011 config DMA_OPS
0012 depends on HAS_DMA
0013 bool
0014
0015 #
0016 # IOMMU drivers that can bypass the IOMMU code and optionally use the direct
0017 # mapping fast path should select this option and set the dma_ops_bypass
0018 # flag in struct device where applicable
0019 #
0020 config DMA_OPS_BYPASS
0021 bool
0022
0023 # Lets platform IOMMU driver choose between bypass and IOMMU
0024 config ARCH_HAS_DMA_MAP_DIRECT
0025 bool
0026
0027 config NEED_SG_DMA_LENGTH
0028 bool
0029
0030 config NEED_DMA_MAP_STATE
0031 bool
0032
0033 config ARCH_DMA_ADDR_T_64BIT
0034 def_bool 64BIT || PHYS_ADDR_T_64BIT
0035
0036 config ARCH_HAS_DMA_SET_MASK
0037 bool
0038
0039 #
0040 # Select this option if the architecture needs special handling for
0041 # DMA_ATTR_WRITE_COMBINE. Normally the "uncached" mapping should be what
0042 # people thing of when saying write combine, so very few platforms should
0043 # need to enable this.
0044 #
0045 config ARCH_HAS_DMA_WRITE_COMBINE
0046 bool
0047
0048 #
0049 # Select if the architectures provides the arch_dma_mark_clean hook
0050 #
0051 config ARCH_HAS_DMA_MARK_CLEAN
0052 bool
0053
0054 config DMA_DECLARE_COHERENT
0055 bool
0056
0057 config ARCH_HAS_SETUP_DMA_OPS
0058 bool
0059
0060 config ARCH_HAS_TEARDOWN_DMA_OPS
0061 bool
0062
0063 config ARCH_HAS_SYNC_DMA_FOR_DEVICE
0064 bool
0065
0066 config ARCH_HAS_SYNC_DMA_FOR_CPU
0067 bool
0068 select NEED_DMA_MAP_STATE
0069
0070 config ARCH_HAS_SYNC_DMA_FOR_CPU_ALL
0071 bool
0072
0073 config ARCH_HAS_DMA_PREP_COHERENT
0074 bool
0075
0076 config ARCH_HAS_FORCE_DMA_UNENCRYPTED
0077 bool
0078
0079 config SWIOTLB
0080 bool
0081 select NEED_DMA_MAP_STATE
0082
0083 config DMA_RESTRICTED_POOL
0084 bool "DMA Restricted Pool"
0085 depends on OF && OF_RESERVED_MEM && SWIOTLB
0086 help
0087 This enables support for restricted DMA pools which provide a level of
0088 DMA memory protection on systems with limited hardware protection
0089 capabilities, such as those lacking an IOMMU.
0090
0091 For more information see
0092 <Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt>
0093 and <kernel/dma/swiotlb.c>.
0094 If unsure, say "n".
0095
0096 #
0097 # Should be selected if we can mmap non-coherent mappings to userspace.
0098 # The only thing that is really required is a way to set an uncached bit
0099 # in the pagetables
0100 #
0101 config DMA_NONCOHERENT_MMAP
0102 default y if !MMU
0103 bool
0104
0105 config DMA_COHERENT_POOL
0106 select GENERIC_ALLOCATOR
0107 bool
0108
0109 config DMA_GLOBAL_POOL
0110 select DMA_DECLARE_COHERENT
0111 bool
0112
0113 config DMA_DIRECT_REMAP
0114 bool
0115 select DMA_COHERENT_POOL
0116 select DMA_NONCOHERENT_MMAP
0117
0118 config DMA_CMA
0119 bool "DMA Contiguous Memory Allocator"
0120 depends on HAVE_DMA_CONTIGUOUS && CMA
0121 help
0122 This enables the Contiguous Memory Allocator which allows drivers
0123 to allocate big physically-contiguous blocks of memory for use with
0124 hardware components that do not support I/O map nor scatter-gather.
0125
0126 You can disable CMA by specifying "cma=0" on the kernel's command
0127 line.
0128
0129 For more information see <kernel/dma/contiguous.c>.
0130 If unsure, say "n".
0131
0132 if DMA_CMA
0133
0134 config DMA_PERNUMA_CMA
0135 bool "Enable separate DMA Contiguous Memory Area for each NUMA Node"
0136 default NUMA && ARM64
0137 help
0138 Enable this option to get pernuma CMA areas so that devices like
0139 ARM64 SMMU can get local memory by DMA coherent APIs.
0140
0141 You can set the size of pernuma CMA by specifying "cma_pernuma=size"
0142 on the kernel's command line.
0143
0144 comment "Default contiguous memory area size:"
0145
0146 config CMA_SIZE_MBYTES
0147 int "Size in Mega Bytes"
0148 depends on !CMA_SIZE_SEL_PERCENTAGE
0149 default 0 if X86
0150 default 16
0151 help
0152 Defines the size (in MiB) of the default memory area for Contiguous
0153 Memory Allocator. If the size of 0 is selected, CMA is disabled by
0154 default, but it can be enabled by passing cma=size[MG] to the kernel.
0155
0156
0157 config CMA_SIZE_PERCENTAGE
0158 int "Percentage of total memory"
0159 depends on !CMA_SIZE_SEL_MBYTES
0160 default 0 if X86
0161 default 10
0162 help
0163 Defines the size of the default memory area for Contiguous Memory
0164 Allocator as a percentage of the total memory in the system.
0165 If 0 percent is selected, CMA is disabled by default, but it can be
0166 enabled by passing cma=size[MG] to the kernel.
0167
0168 choice
0169 prompt "Selected region size"
0170 default CMA_SIZE_SEL_MBYTES
0171
0172 config CMA_SIZE_SEL_MBYTES
0173 bool "Use mega bytes value only"
0174
0175 config CMA_SIZE_SEL_PERCENTAGE
0176 bool "Use percentage value only"
0177
0178 config CMA_SIZE_SEL_MIN
0179 bool "Use lower value (minimum)"
0180
0181 config CMA_SIZE_SEL_MAX
0182 bool "Use higher value (maximum)"
0183
0184 endchoice
0185
0186 config CMA_ALIGNMENT
0187 int "Maximum PAGE_SIZE order of alignment for contiguous buffers"
0188 range 2 12
0189 default 8
0190 help
0191 DMA mapping framework by default aligns all buffers to the smallest
0192 PAGE_SIZE order which is greater than or equal to the requested buffer
0193 size. This works well for buffers up to a few hundreds kilobytes, but
0194 for larger buffers it just a memory waste. With this parameter you can
0195 specify the maximum PAGE_SIZE order for contiguous buffers. Larger
0196 buffers will be aligned only to this specified order. The order is
0197 expressed as a power of two multiplied by the PAGE_SIZE.
0198
0199 For example, if your system defaults to 4KiB pages, the order value
0200 of 8 means that the buffers will be aligned up to 1MiB only.
0201
0202 If unsure, leave the default value "8".
0203
0204 endif
0205
0206 config DMA_API_DEBUG
0207 bool "Enable debugging of DMA-API usage"
0208 select NEED_DMA_MAP_STATE
0209 help
0210 Enable this option to debug the use of the DMA API by device drivers.
0211 With this option you will be able to detect common bugs in device
0212 drivers like double-freeing of DMA mappings or freeing mappings that
0213 were never allocated.
0214
0215 This option causes a performance degradation. Use only if you want to
0216 debug device drivers and dma interactions.
0217
0218 If unsure, say N.
0219
0220 config DMA_API_DEBUG_SG
0221 bool "Debug DMA scatter-gather usage"
0222 default y
0223 depends on DMA_API_DEBUG
0224 help
0225 Perform extra checking that callers of dma_map_sg() have respected the
0226 appropriate segment length/boundary limits for the given device when
0227 preparing DMA scatterlists.
0228
0229 This is particularly likely to have been overlooked in cases where the
0230 dma_map_sg() API is used for general bulk mapping of pages rather than
0231 preparing literal scatter-gather descriptors, where there is a risk of
0232 unexpected behaviour from DMA API implementations if the scatterlist
0233 is technically out-of-spec.
0234
0235 If unsure, say N.
0236
0237 config DMA_MAP_BENCHMARK
0238 bool "Enable benchmarking of streaming DMA mapping"
0239 depends on DEBUG_FS
0240 help
0241 Provides /sys/kernel/debug/dma_map_benchmark that helps with testing
0242 performance of dma_(un)map_page.
0243
0244 See tools/testing/selftests/dma/dma_map_benchmark.c
