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_FLAGS
30 config NEED_SG_DMA_LENGTH
33 config NEED_DMA_MAP_STATE
36 config ARCH_DMA_ADDR_T_64BIT
37 def_bool 64BIT || PHYS_ADDR_T_64BIT
39 config ARCH_HAS_DMA_SET_MASK
43 # Select this option if the architecture needs special handling for
44 # DMA_ATTR_WRITE_COMBINE. Normally the "uncached" mapping should be what
45 # people think of when saying write combine, so very few platforms should
46 # need to enable this.
48 config ARCH_HAS_DMA_WRITE_COMBINE
52 # Select if the architectures provides the arch_dma_mark_clean hook
54 config ARCH_HAS_DMA_MARK_CLEAN
57 config DMA_DECLARE_COHERENT
60 config ARCH_HAS_SETUP_DMA_OPS
63 config ARCH_HAS_TEARDOWN_DMA_OPS
66 config ARCH_HAS_SYNC_DMA_FOR_DEVICE
69 config ARCH_HAS_SYNC_DMA_FOR_CPU
71 select NEED_DMA_MAP_STATE
73 config ARCH_HAS_SYNC_DMA_FOR_CPU_ALL
76 config ARCH_HAS_DMA_PREP_COHERENT
79 config ARCH_HAS_FORCE_DMA_UNENCRYPTED
83 # Select this option if the architecture assumes DMA devices are coherent
86 config ARCH_DMA_DEFAULT_COHERENT
91 select NEED_DMA_MAP_STATE
93 config SWIOTLB_DYNAMIC
94 bool "Dynamic allocation of DMA bounce buffers"
98 This enables dynamic resizing of the software IO TLB. The kernel
99 starts with one memory pool at boot and it will allocate additional
100 pools as needed. To reduce run-time kernel memory requirements, you
101 may have to specify a smaller size of the initial pool using
102 "swiotlb=" on the kernel command line.
106 config DMA_BOUNCE_UNALIGNED_KMALLOC
110 config DMA_RESTRICTED_POOL
111 bool "DMA Restricted Pool"
112 depends on OF && OF_RESERVED_MEM && SWIOTLB
114 This enables support for restricted DMA pools which provide a level of
115 DMA memory protection on systems with limited hardware protection
116 capabilities, such as those lacking an IOMMU.
118 For more information see
119 <Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt>
120 and <kernel/dma/swiotlb.c>.
124 # Should be selected if we can mmap non-coherent mappings to userspace.
125 # The only thing that is really required is a way to set an uncached bit
128 config DMA_NONCOHERENT_MMAP
132 config DMA_COHERENT_POOL
133 select GENERIC_ALLOCATOR
136 config DMA_GLOBAL_POOL
137 select DMA_DECLARE_COHERENT
140 config DMA_DIRECT_REMAP
142 select DMA_COHERENT_POOL
143 select DMA_NONCOHERENT_MMAP
146 bool "DMA Contiguous Memory Allocator"
147 depends on HAVE_DMA_CONTIGUOUS && CMA
149 This enables the Contiguous Memory Allocator which allows drivers
150 to allocate big physically-contiguous blocks of memory for use with
151 hardware components that do not support I/O map nor scatter-gather.
153 You can disable CMA by specifying "cma=0" on the kernel's command
156 For more information see <kernel/dma/contiguous.c>.
162 bool "Enable separate DMA Contiguous Memory Area for NUMA Node"
165 Enable this option to get numa CMA areas so that NUMA devices
166 can get local memory by DMA coherent APIs.
168 You can set the size of pernuma CMA by specifying "cma_pernuma=size"
169 or set the node id and its size of CMA by specifying "numa_cma=
170 <node>:size[,<node>:size]" on the kernel's command line.
172 comment "Default contiguous memory area size:"
174 config CMA_SIZE_MBYTES
175 int "Size in Mega Bytes"
176 depends on !CMA_SIZE_SEL_PERCENTAGE
180 Defines the size (in MiB) of the default memory area for Contiguous
181 Memory Allocator. If the size of 0 is selected, CMA is disabled by
182 default, but it can be enabled by passing cma=size[MG] to the kernel.
185 config CMA_SIZE_PERCENTAGE
186 int "Percentage of total memory"
187 depends on !CMA_SIZE_SEL_MBYTES
191 Defines the size of the default memory area for Contiguous Memory
192 Allocator as a percentage of the total memory in the system.
193 If 0 percent is selected, CMA is disabled by default, but it can be
194 enabled by passing cma=size[MG] to the kernel.
197 prompt "Selected region size"
198 default CMA_SIZE_SEL_MBYTES
200 config CMA_SIZE_SEL_MBYTES
201 bool "Use mega bytes value only"
203 config CMA_SIZE_SEL_PERCENTAGE
204 bool "Use percentage value only"
206 config CMA_SIZE_SEL_MIN
207 bool "Use lower value (minimum)"
209 config CMA_SIZE_SEL_MAX
210 bool "Use higher value (maximum)"
215 int "Maximum PAGE_SIZE order of alignment for contiguous buffers"
219 DMA mapping framework by default aligns all buffers to the smallest
220 PAGE_SIZE order which is greater than or equal to the requested buffer
221 size. This works well for buffers up to a few hundreds kilobytes, but
222 for larger buffers it just a memory waste. With this parameter you can
223 specify the maximum PAGE_SIZE order for contiguous buffers. Larger
224 buffers will be aligned only to this specified order. The order is
225 expressed as a power of two multiplied by the PAGE_SIZE.
227 For example, if your system defaults to 4KiB pages, the order value
228 of 8 means that the buffers will be aligned up to 1MiB only.
230 If unsure, leave the default value "8".
235 bool "Enable debugging of DMA-API usage"
236 select NEED_DMA_MAP_STATE
238 Enable this option to debug the use of the DMA API by device drivers.
239 With this option you will be able to detect common bugs in device
240 drivers like double-freeing of DMA mappings or freeing mappings that
241 were never allocated.
243 This option causes a performance degradation. Use only if you want to
244 debug device drivers and dma interactions.
248 config DMA_API_DEBUG_SG
249 bool "Debug DMA scatter-gather usage"
251 depends on DMA_API_DEBUG
253 Perform extra checking that callers of dma_map_sg() have respected the
254 appropriate segment length/boundary limits for the given device when
255 preparing DMA scatterlists.
257 This is particularly likely to have been overlooked in cases where the
258 dma_map_sg() API is used for general bulk mapping of pages rather than
259 preparing literal scatter-gather descriptors, where there is a risk of
260 unexpected behaviour from DMA API implementations if the scatterlist
261 is technically out-of-spec.
265 config DMA_MAP_BENCHMARK
266 bool "Enable benchmarking of streaming DMA mapping"
269 Provides /sys/kernel/debug/dma_map_benchmark that helps with testing
270 performance of dma_(un)map_page.
272 See tools/testing/selftests/dma/dma_map_benchmark.c