1# SPDX-License-Identifier: GPL-2.0-only 2 3config NO_DMA 4 bool 5 6config HAS_DMA 7 bool 8 depends on !NO_DMA 9 default y 10 11config DMA_OPS 12 depends on HAS_DMA 13 bool 14 15# 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 19# 20config DMA_OPS_BYPASS 21 bool 22 23# Lets platform IOMMU driver choose between bypass and IOMMU 24config ARCH_HAS_DMA_MAP_DIRECT 25 bool 26 27config NEED_SG_DMA_LENGTH 28 bool 29 30config NEED_DMA_MAP_STATE 31 bool 32 33config ARCH_DMA_ADDR_T_64BIT 34 def_bool 64BIT || PHYS_ADDR_T_64BIT 35 36config ARCH_HAS_DMA_SET_MASK 37 bool 38 39# 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. 44# 45config ARCH_HAS_DMA_WRITE_COMBINE 46 bool 47 48# 49# Select if the architectures provides the arch_dma_mark_clean hook 50# 51config ARCH_HAS_DMA_MARK_CLEAN 52 bool 53 54config DMA_DECLARE_COHERENT 55 bool 56 57config ARCH_HAS_SETUP_DMA_OPS 58 bool 59 60config ARCH_HAS_TEARDOWN_DMA_OPS 61 bool 62 63config ARCH_HAS_SYNC_DMA_FOR_DEVICE 64 bool 65 66config ARCH_HAS_SYNC_DMA_FOR_CPU 67 bool 68 select NEED_DMA_MAP_STATE 69 70config ARCH_HAS_SYNC_DMA_FOR_CPU_ALL 71 bool 72 73config ARCH_HAS_DMA_PREP_COHERENT 74 bool 75 76config ARCH_HAS_FORCE_DMA_UNENCRYPTED 77 bool 78 79config SWIOTLB 80 bool 81 select NEED_DMA_MAP_STATE 82 83config DMA_RESTRICTED_POOL 84 bool "DMA Restricted Pool" 85 depends on OF && OF_RESERVED_MEM && SWIOTLB 86 help 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. 90 91 For more information see 92 <Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt> 93 and <kernel/dma/swiotlb.c>. 94 If unsure, say "n". 95 96# 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 99# in the pagetables 100# 101config DMA_NONCOHERENT_MMAP 102 default y if !MMU 103 bool 104 105config DMA_COHERENT_POOL 106 select GENERIC_ALLOCATOR 107 bool 108 109config DMA_REMAP 110 bool 111 depends on MMU 112 select DMA_NONCOHERENT_MMAP 113 114config DMA_DIRECT_REMAP 115 bool 116 select DMA_REMAP 117 select DMA_COHERENT_POOL 118 119config DMA_CMA 120 bool "DMA Contiguous Memory Allocator" 121 depends on HAVE_DMA_CONTIGUOUS && CMA 122 help 123 This enables the Contiguous Memory Allocator which allows drivers 124 to allocate big physically-contiguous blocks of memory for use with 125 hardware components that do not support I/O map nor scatter-gather. 126 127 You can disable CMA by specifying "cma=0" on the kernel's command 128 line. 129 130 For more information see <kernel/dma/contiguous.c>. 131 If unsure, say "n". 132 133if DMA_CMA 134 135config DMA_PERNUMA_CMA 136 bool "Enable separate DMA Contiguous Memory Area for each NUMA Node" 137 default NUMA && ARM64 138 help 139 Enable this option to get pernuma CMA areas so that devices like 140 ARM64 SMMU can get local memory by DMA coherent APIs. 141 142 You can set the size of pernuma CMA by specifying "cma_pernuma=size" 143 on the kernel's command line. 144 145comment "Default contiguous memory area size:" 146 147config CMA_SIZE_MBYTES 148 int "Size in Mega Bytes" 149 depends on !CMA_SIZE_SEL_PERCENTAGE 150 default 0 if X86 151 default 16 152 help 153 Defines the size (in MiB) of the default memory area for Contiguous 154 Memory Allocator. If the size of 0 is selected, CMA is disabled by 155 default, but it can be enabled by passing cma=size[MG] to the kernel. 156 157 158config CMA_SIZE_PERCENTAGE 159 int "Percentage of total memory" 160 depends on !CMA_SIZE_SEL_MBYTES 161 default 0 if X86 162 default 10 163 help 164 Defines the size of the default memory area for Contiguous Memory 165 Allocator as a percentage of the total memory in the system. 166 If 0 percent is selected, CMA is disabled by default, but it can be 167 enabled by passing cma=size[MG] to the kernel. 168 169choice 170 prompt "Selected region size" 171 default CMA_SIZE_SEL_MBYTES 172 173config CMA_SIZE_SEL_MBYTES 174 bool "Use mega bytes value only" 175 176config CMA_SIZE_SEL_PERCENTAGE 177 bool "Use percentage value only" 178 179config CMA_SIZE_SEL_MIN 180 bool "Use lower value (minimum)" 181 182config CMA_SIZE_SEL_MAX 183 bool "Use higher value (maximum)" 184 185endchoice 186 187config CMA_ALIGNMENT 188 int "Maximum PAGE_SIZE order of alignment for contiguous buffers" 189 range 2 12 190 default 8 191 help 192 DMA mapping framework by default aligns all buffers to the smallest 193 PAGE_SIZE order which is greater than or equal to the requested buffer 194 size. This works well for buffers up to a few hundreds kilobytes, but 195 for larger buffers it just a memory waste. With this parameter you can 196 specify the maximum PAGE_SIZE order for contiguous buffers. Larger 197 buffers will be aligned only to this specified order. The order is 198 expressed as a power of two multiplied by the PAGE_SIZE. 199 200 For example, if your system defaults to 4KiB pages, the order value 201 of 8 means that the buffers will be aligned up to 1MiB only. 202 203 If unsure, leave the default value "8". 204 205endif 206 207config DMA_API_DEBUG 208 bool "Enable debugging of DMA-API usage" 209 select NEED_DMA_MAP_STATE 210 help 211 Enable this option to debug the use of the DMA API by device drivers. 212 With this option you will be able to detect common bugs in device 213 drivers like double-freeing of DMA mappings or freeing mappings that 214 were never allocated. 215 216 This option causes a performance degradation. Use only if you want to 217 debug device drivers and dma interactions. 218 219 If unsure, say N. 220 221config DMA_API_DEBUG_SG 222 bool "Debug DMA scatter-gather usage" 223 default y 224 depends on DMA_API_DEBUG 225 help 226 Perform extra checking that callers of dma_map_sg() have respected the 227 appropriate segment length/boundary limits for the given device when 228 preparing DMA scatterlists. 229 230 This is particularly likely to have been overlooked in cases where the 231 dma_map_sg() API is used for general bulk mapping of pages rather than 232 preparing literal scatter-gather descriptors, where there is a risk of 233 unexpected behaviour from DMA API implementations if the scatterlist 234 is technically out-of-spec. 235 236 If unsure, say N. 237 238config DMA_MAP_BENCHMARK 239 bool "Enable benchmarking of streaming DMA mapping" 240 depends on DEBUG_FS 241 help 242 Provides /sys/kernel/debug/dma_map_benchmark that helps with testing 243 performance of dma_(un)map_page. 244 245 See tools/testing/selftests/dma/dma_map_benchmark.c 246