1 # SPDX-License-Identifier: GPL-2.0-only
16 # IOMMU drivers that can bypass the IOMMU code and optionally use the direct
17 # mapping fast path should select this option and set the dma_ops_bypass
18 # flag in struct device where applicable
23 # Lets platform IOMMU driver choose between bypass and IOMMU
24 config ARCH_HAS_DMA_MAP_DIRECT
27 config NEED_SG_DMA_LENGTH
30 config NEED_DMA_MAP_STATE
33 config ARCH_DMA_ADDR_T_64BIT
34 def_bool 64BIT || PHYS_ADDR_T_64BIT
36 config ARCH_HAS_DMA_SET_MASK
40 # Select this option if the architecture needs special handling for
41 # DMA_ATTR_WRITE_COMBINE. Normally the "uncached" mapping should be what
42 # people thing of when saying write combine, so very few platforms should
43 # need to enable this.
45 config ARCH_HAS_DMA_WRITE_COMBINE
49 # Select if the architectures provides the arch_dma_mark_clean hook
51 config ARCH_HAS_DMA_MARK_CLEAN
54 config DMA_DECLARE_COHERENT
57 config ARCH_HAS_SETUP_DMA_OPS
60 config ARCH_HAS_TEARDOWN_DMA_OPS
63 config ARCH_HAS_SYNC_DMA_FOR_DEVICE
66 config ARCH_HAS_SYNC_DMA_FOR_CPU
68 select NEED_DMA_MAP_STATE
70 config ARCH_HAS_SYNC_DMA_FOR_CPU_ALL
73 config ARCH_HAS_DMA_PREP_COHERENT
76 config ARCH_HAS_FORCE_DMA_UNENCRYPTED
81 select NEED_DMA_MAP_STATE
83 config DMA_RESTRICTED_POOL
84 bool "DMA Restricted Pool"
85 depends on OF && OF_RESERVED_MEM && SWIOTLB
87 This enables support for restricted DMA pools which provide a level of
88 DMA memory protection on systems with limited hardware protection
89 capabilities, such as those lacking an IOMMU.
91 For more information see
92 <Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt>
93 and <kernel/dma/swiotlb.c>.
97 # Should be selected if we can mmap non-coherent mappings to userspace.
98 # The only thing that is really required is a way to set an uncached bit
101 config DMA_NONCOHERENT_MMAP
105 config DMA_COHERENT_POOL
106 select GENERIC_ALLOCATOR
109 config DMA_GLOBAL_POOL
110 select DMA_DECLARE_COHERENT
116 select DMA_NONCOHERENT_MMAP
118 config DMA_DIRECT_REMAP
121 select DMA_COHERENT_POOL
124 bool "DMA Contiguous Memory Allocator"
125 depends on HAVE_DMA_CONTIGUOUS && CMA
127 This enables the Contiguous Memory Allocator which allows drivers
128 to allocate big physically-contiguous blocks of memory for use with
129 hardware components that do not support I/O map nor scatter-gather.
131 You can disable CMA by specifying "cma=0" on the kernel's command
134 For more information see <kernel/dma/contiguous.c>.
139 config DMA_PERNUMA_CMA
140 bool "Enable separate DMA Contiguous Memory Area for each NUMA Node"
141 default NUMA && ARM64
143 Enable this option to get pernuma CMA areas so that devices like
144 ARM64 SMMU can get local memory by DMA coherent APIs.
146 You can set the size of pernuma CMA by specifying "cma_pernuma=size"
147 on the kernel's command line.
149 comment "Default contiguous memory area size:"
151 config CMA_SIZE_MBYTES
152 int "Size in Mega Bytes"
153 depends on !CMA_SIZE_SEL_PERCENTAGE
157 Defines the size (in MiB) of the default memory area for Contiguous
158 Memory Allocator. If the size of 0 is selected, CMA is disabled by
159 default, but it can be enabled by passing cma=size[MG] to the kernel.
162 config CMA_SIZE_PERCENTAGE
163 int "Percentage of total memory"
164 depends on !CMA_SIZE_SEL_MBYTES
168 Defines the size of the default memory area for Contiguous Memory
169 Allocator as a percentage of the total memory in the system.
170 If 0 percent is selected, CMA is disabled by default, but it can be
171 enabled by passing cma=size[MG] to the kernel.
174 prompt "Selected region size"
175 default CMA_SIZE_SEL_MBYTES
177 config CMA_SIZE_SEL_MBYTES
178 bool "Use mega bytes value only"
180 config CMA_SIZE_SEL_PERCENTAGE
181 bool "Use percentage value only"
183 config CMA_SIZE_SEL_MIN
184 bool "Use lower value (minimum)"
186 config CMA_SIZE_SEL_MAX
187 bool "Use higher value (maximum)"
192 int "Maximum PAGE_SIZE order of alignment for contiguous buffers"
196 DMA mapping framework by default aligns all buffers to the smallest
197 PAGE_SIZE order which is greater than or equal to the requested buffer
198 size. This works well for buffers up to a few hundreds kilobytes, but
199 for larger buffers it just a memory waste. With this parameter you can
200 specify the maximum PAGE_SIZE order for contiguous buffers. Larger
201 buffers will be aligned only to this specified order. The order is
202 expressed as a power of two multiplied by the PAGE_SIZE.
204 For example, if your system defaults to 4KiB pages, the order value
205 of 8 means that the buffers will be aligned up to 1MiB only.
207 If unsure, leave the default value "8".
212 bool "Enable debugging of DMA-API usage"
213 select NEED_DMA_MAP_STATE
215 Enable this option to debug the use of the DMA API by device drivers.
216 With this option you will be able to detect common bugs in device
217 drivers like double-freeing of DMA mappings or freeing mappings that
218 were never allocated.
220 This option causes a performance degradation. Use only if you want to
221 debug device drivers and dma interactions.
225 config DMA_API_DEBUG_SG
226 bool "Debug DMA scatter-gather usage"
228 depends on DMA_API_DEBUG
230 Perform extra checking that callers of dma_map_sg() have respected the
231 appropriate segment length/boundary limits for the given device when
232 preparing DMA scatterlists.
234 This is particularly likely to have been overlooked in cases where the
235 dma_map_sg() API is used for general bulk mapping of pages rather than
236 preparing literal scatter-gather descriptors, where there is a risk of
237 unexpected behaviour from DMA API implementations if the scatterlist
238 is technically out-of-spec.
242 config DMA_MAP_BENCHMARK
243 bool "Enable benchmarking of streaming DMA mapping"
246 Provides /sys/kernel/debug/dma_map_benchmark that helps with testing
247 performance of dma_(un)map_page.
249 See tools/testing/selftests/dma/dma_map_benchmark.c