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 config NEED_SG_DMA_LENGTH
26 config NEED_DMA_MAP_STATE
29 config ARCH_DMA_ADDR_T_64BIT
30 def_bool 64BIT || PHYS_ADDR_T_64BIT
32 config ARCH_HAS_DMA_COHERENCE_H
35 config ARCH_HAS_DMA_SET_MASK
39 # Select this option if the architecture needs special handling for
40 # DMA_ATTR_WRITE_COMBINE. Normally the "uncached" mapping should be what
41 # people thing of when saying write combine, so very few platforms should
42 # need to enable this.
44 config ARCH_HAS_DMA_WRITE_COMBINE
48 # Select if the architectures provides the arch_dma_mark_clean hook
50 config ARCH_HAS_DMA_MARK_CLEAN
53 config DMA_DECLARE_COHERENT
56 config ARCH_HAS_SETUP_DMA_OPS
59 config ARCH_HAS_TEARDOWN_DMA_OPS
62 config ARCH_HAS_SYNC_DMA_FOR_DEVICE
65 config ARCH_HAS_SYNC_DMA_FOR_CPU
67 select NEED_DMA_MAP_STATE
69 config ARCH_HAS_SYNC_DMA_FOR_CPU_ALL
72 config ARCH_HAS_DMA_PREP_COHERENT
75 config ARCH_HAS_FORCE_DMA_UNENCRYPTED
80 select NEED_DMA_MAP_STATE
83 # Should be selected if we can mmap non-coherent mappings to userspace.
84 # The only thing that is really required is a way to set an uncached bit
87 config DMA_NONCOHERENT_MMAP
91 config DMA_COHERENT_POOL
92 select GENERIC_ALLOCATOR
98 select DMA_NONCOHERENT_MMAP
100 config DMA_DIRECT_REMAP
103 select DMA_COHERENT_POOL
106 bool "DMA Contiguous Memory Allocator"
107 depends on HAVE_DMA_CONTIGUOUS && CMA
109 This enables the Contiguous Memory Allocator which allows drivers
110 to allocate big physically-contiguous blocks of memory for use with
111 hardware components that do not support I/O map nor scatter-gather.
113 You can disable CMA by specifying "cma=0" on the kernel's command
116 For more information see <kernel/dma/contiguous.c>.
121 config DMA_PERNUMA_CMA
122 bool "Enable separate DMA Contiguous Memory Area for each NUMA Node"
123 default NUMA && ARM64
125 Enable this option to get pernuma CMA areas so that devices like
126 ARM64 SMMU can get local memory by DMA coherent APIs.
128 You can set the size of pernuma CMA by specifying "cma_pernuma=size"
129 on the kernel's command line.
131 comment "Default contiguous memory area size:"
133 config CMA_SIZE_MBYTES
134 int "Size in Mega Bytes"
135 depends on !CMA_SIZE_SEL_PERCENTAGE
139 Defines the size (in MiB) of the default memory area for Contiguous
140 Memory Allocator. If the size of 0 is selected, CMA is disabled by
141 default, but it can be enabled by passing cma=size[MG] to the kernel.
144 config CMA_SIZE_PERCENTAGE
145 int "Percentage of total memory"
146 depends on !CMA_SIZE_SEL_MBYTES
150 Defines the size of the default memory area for Contiguous Memory
151 Allocator as a percentage of the total memory in the system.
152 If 0 percent is selected, CMA is disabled by default, but it can be
153 enabled by passing cma=size[MG] to the kernel.
156 prompt "Selected region size"
157 default CMA_SIZE_SEL_MBYTES
159 config CMA_SIZE_SEL_MBYTES
160 bool "Use mega bytes value only"
162 config CMA_SIZE_SEL_PERCENTAGE
163 bool "Use percentage value only"
165 config CMA_SIZE_SEL_MIN
166 bool "Use lower value (minimum)"
168 config CMA_SIZE_SEL_MAX
169 bool "Use higher value (maximum)"
174 int "Maximum PAGE_SIZE order of alignment for contiguous buffers"
178 DMA mapping framework by default aligns all buffers to the smallest
179 PAGE_SIZE order which is greater than or equal to the requested buffer
180 size. This works well for buffers up to a few hundreds kilobytes, but
181 for larger buffers it just a memory waste. With this parameter you can
182 specify the maximum PAGE_SIZE order for contiguous buffers. Larger
183 buffers will be aligned only to this specified order. The order is
184 expressed as a power of two multiplied by the PAGE_SIZE.
186 For example, if your system defaults to 4KiB pages, the order value
187 of 8 means that the buffers will be aligned up to 1MiB only.
189 If unsure, leave the default value "8".
194 bool "Enable debugging of DMA-API usage"
195 select NEED_DMA_MAP_STATE
197 Enable this option to debug the use of the DMA API by device drivers.
198 With this option you will be able to detect common bugs in device
199 drivers like double-freeing of DMA mappings or freeing mappings that
200 were never allocated.
202 This option causes a performance degradation. Use only if you want to
203 debug device drivers and dma interactions.
207 config DMA_API_DEBUG_SG
208 bool "Debug DMA scatter-gather usage"
210 depends on DMA_API_DEBUG
212 Perform extra checking that callers of dma_map_sg() have respected the
213 appropriate segment length/boundary limits for the given device when
214 preparing DMA scatterlists.
216 This is particularly likely to have been overlooked in cases where the
217 dma_map_sg() API is used for general bulk mapping of pages rather than
218 preparing literal scatter-gather descriptors, where there is a risk of
219 unexpected behaviour from DMA API implementations if the scatterlist
220 is technically out-of-spec.