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