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_FLAGS 28 bool 29 30config NEED_SG_DMA_LENGTH 31 bool 32 33config NEED_DMA_MAP_STATE 34 bool 35 36config ARCH_DMA_ADDR_T_64BIT 37 def_bool 64BIT || PHYS_ADDR_T_64BIT 38 39config ARCH_HAS_DMA_SET_MASK 40 bool 41 42# 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. 47# 48config ARCH_HAS_DMA_WRITE_COMBINE 49 bool 50 51# 52# Select if the architectures provides the arch_dma_mark_clean hook 53# 54config ARCH_HAS_DMA_MARK_CLEAN 55 bool 56 57config DMA_DECLARE_COHERENT 58 bool 59 60config ARCH_HAS_SETUP_DMA_OPS 61 bool 62 63config ARCH_HAS_TEARDOWN_DMA_OPS 64 bool 65 66config ARCH_HAS_SYNC_DMA_FOR_DEVICE 67 bool 68 69config ARCH_HAS_SYNC_DMA_FOR_CPU 70 bool 71 select NEED_DMA_MAP_STATE 72 73config ARCH_HAS_SYNC_DMA_FOR_CPU_ALL 74 bool 75 76config ARCH_HAS_DMA_PREP_COHERENT 77 bool 78 79config ARCH_HAS_FORCE_DMA_UNENCRYPTED 80 bool 81 82# 83# Select this option if the architecture assumes DMA devices are coherent 84# by default. 85# 86config ARCH_DMA_DEFAULT_COHERENT 87 bool 88 89config SWIOTLB 90 bool 91 select NEED_DMA_MAP_STATE 92 93config DMA_BOUNCE_UNALIGNED_KMALLOC 94 bool 95 depends on SWIOTLB 96 97config DMA_RESTRICTED_POOL 98 bool "DMA Restricted Pool" 99 depends on OF && OF_RESERVED_MEM && SWIOTLB 100 help 101 This enables support for restricted DMA pools which provide a level of 102 DMA memory protection on systems with limited hardware protection 103 capabilities, such as those lacking an IOMMU. 104 105 For more information see 106 <Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt> 107 and <kernel/dma/swiotlb.c>. 108 If unsure, say "n". 109 110# 111# Should be selected if we can mmap non-coherent mappings to userspace. 112# The only thing that is really required is a way to set an uncached bit 113# in the pagetables 114# 115config DMA_NONCOHERENT_MMAP 116 default y if !MMU 117 bool 118 119config DMA_COHERENT_POOL 120 select GENERIC_ALLOCATOR 121 bool 122 123config DMA_GLOBAL_POOL 124 select DMA_DECLARE_COHERENT 125 bool 126 127config DMA_DIRECT_REMAP 128 bool 129 select DMA_COHERENT_POOL 130 select DMA_NONCOHERENT_MMAP 131 132config DMA_CMA 133 bool "DMA Contiguous Memory Allocator" 134 depends on HAVE_DMA_CONTIGUOUS && CMA 135 help 136 This enables the Contiguous Memory Allocator which allows drivers 137 to allocate big physically-contiguous blocks of memory for use with 138 hardware components that do not support I/O map nor scatter-gather. 139 140 You can disable CMA by specifying "cma=0" on the kernel's command 141 line. 142 143 For more information see <kernel/dma/contiguous.c>. 144 If unsure, say "n". 145 146if DMA_CMA 147 148config DMA_PERNUMA_CMA 149 bool "Enable separate DMA Contiguous Memory Area for each NUMA Node" 150 default NUMA && ARM64 151 help 152 Enable this option to get pernuma CMA areas so that devices like 153 ARM64 SMMU can get local memory by DMA coherent APIs. 154 155 You can set the size of pernuma CMA by specifying "cma_pernuma=size" 156 on the kernel's command line. 157 158comment "Default contiguous memory area size:" 159 160config CMA_SIZE_MBYTES 161 int "Size in Mega Bytes" 162 depends on !CMA_SIZE_SEL_PERCENTAGE 163 default 0 if X86 164 default 16 165 help 166 Defines the size (in MiB) of the default memory area for Contiguous 167 Memory Allocator. If the size of 0 is selected, CMA is disabled by 168 default, but it can be enabled by passing cma=size[MG] to the kernel. 169 170 171config CMA_SIZE_PERCENTAGE 172 int "Percentage of total memory" 173 depends on !CMA_SIZE_SEL_MBYTES 174 default 0 if X86 175 default 10 176 help 177 Defines the size of the default memory area for Contiguous Memory 178 Allocator as a percentage of the total memory in the system. 179 If 0 percent is selected, CMA is disabled by default, but it can be 180 enabled by passing cma=size[MG] to the kernel. 181 182choice 183 prompt "Selected region size" 184 default CMA_SIZE_SEL_MBYTES 185 186config CMA_SIZE_SEL_MBYTES 187 bool "Use mega bytes value only" 188 189config CMA_SIZE_SEL_PERCENTAGE 190 bool "Use percentage value only" 191 192config CMA_SIZE_SEL_MIN 193 bool "Use lower value (minimum)" 194 195config CMA_SIZE_SEL_MAX 196 bool "Use higher value (maximum)" 197 198endchoice 199 200config CMA_ALIGNMENT 201 int "Maximum PAGE_SIZE order of alignment for contiguous buffers" 202 range 2 12 203 default 8 204 help 205 DMA mapping framework by default aligns all buffers to the smallest 206 PAGE_SIZE order which is greater than or equal to the requested buffer 207 size. This works well for buffers up to a few hundreds kilobytes, but 208 for larger buffers it just a memory waste. With this parameter you can 209 specify the maximum PAGE_SIZE order for contiguous buffers. Larger 210 buffers will be aligned only to this specified order. The order is 211 expressed as a power of two multiplied by the PAGE_SIZE. 212 213 For example, if your system defaults to 4KiB pages, the order value 214 of 8 means that the buffers will be aligned up to 1MiB only. 215 216 If unsure, leave the default value "8". 217 218endif 219 220config DMA_API_DEBUG 221 bool "Enable debugging of DMA-API usage" 222 select NEED_DMA_MAP_STATE 223 help 224 Enable this option to debug the use of the DMA API by device drivers. 225 With this option you will be able to detect common bugs in device 226 drivers like double-freeing of DMA mappings or freeing mappings that 227 were never allocated. 228 229 This option causes a performance degradation. Use only if you want to 230 debug device drivers and dma interactions. 231 232 If unsure, say N. 233 234config DMA_API_DEBUG_SG 235 bool "Debug DMA scatter-gather usage" 236 default y 237 depends on DMA_API_DEBUG 238 help 239 Perform extra checking that callers of dma_map_sg() have respected the 240 appropriate segment length/boundary limits for the given device when 241 preparing DMA scatterlists. 242 243 This is particularly likely to have been overlooked in cases where the 244 dma_map_sg() API is used for general bulk mapping of pages rather than 245 preparing literal scatter-gather descriptors, where there is a risk of 246 unexpected behaviour from DMA API implementations if the scatterlist 247 is technically out-of-spec. 248 249 If unsure, say N. 250 251config DMA_MAP_BENCHMARK 252 bool "Enable benchmarking of streaming DMA mapping" 253 depends on DEBUG_FS 254 help 255 Provides /sys/kernel/debug/dma_map_benchmark that helps with testing 256 performance of dma_(un)map_page. 257 258 See tools/testing/selftests/dma/dma_map_benchmark.c 259