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_GLOBAL_POOL 110 select DMA_DECLARE_COHERENT 111 bool 112 113config DMA_REMAP 114 bool 115 depends on MMU 116 select DMA_NONCOHERENT_MMAP 117 118config DMA_DIRECT_REMAP 119 bool 120 select DMA_REMAP 121 select DMA_COHERENT_POOL 122 123config DMA_CMA 124 bool "DMA Contiguous Memory Allocator" 125 depends on HAVE_DMA_CONTIGUOUS && CMA 126 help 127 This enables the Contiguous Memory Allocator which allows drivers 128 to allocate big physically-contiguous blocks of memory for use with 129 hardware components that do not support I/O map nor scatter-gather. 130 131 You can disable CMA by specifying "cma=0" on the kernel's command 132 line. 133 134 For more information see <kernel/dma/contiguous.c>. 135 If unsure, say "n". 136 137if DMA_CMA 138 139config DMA_PERNUMA_CMA 140 bool "Enable separate DMA Contiguous Memory Area for each NUMA Node" 141 default NUMA && ARM64 142 help 143 Enable this option to get pernuma CMA areas so that devices like 144 ARM64 SMMU can get local memory by DMA coherent APIs. 145 146 You can set the size of pernuma CMA by specifying "cma_pernuma=size" 147 on the kernel's command line. 148 149comment "Default contiguous memory area size:" 150 151config CMA_SIZE_MBYTES 152 int "Size in Mega Bytes" 153 depends on !CMA_SIZE_SEL_PERCENTAGE 154 default 0 if X86 155 default 16 156 help 157 Defines the size (in MiB) of the default memory area for Contiguous 158 Memory Allocator. If the size of 0 is selected, CMA is disabled by 159 default, but it can be enabled by passing cma=size[MG] to the kernel. 160 161 162config CMA_SIZE_PERCENTAGE 163 int "Percentage of total memory" 164 depends on !CMA_SIZE_SEL_MBYTES 165 default 0 if X86 166 default 10 167 help 168 Defines the size of the default memory area for Contiguous Memory 169 Allocator as a percentage of the total memory in the system. 170 If 0 percent is selected, CMA is disabled by default, but it can be 171 enabled by passing cma=size[MG] to the kernel. 172 173choice 174 prompt "Selected region size" 175 default CMA_SIZE_SEL_MBYTES 176 177config CMA_SIZE_SEL_MBYTES 178 bool "Use mega bytes value only" 179 180config CMA_SIZE_SEL_PERCENTAGE 181 bool "Use percentage value only" 182 183config CMA_SIZE_SEL_MIN 184 bool "Use lower value (minimum)" 185 186config CMA_SIZE_SEL_MAX 187 bool "Use higher value (maximum)" 188 189endchoice 190 191config CMA_ALIGNMENT 192 int "Maximum PAGE_SIZE order of alignment for contiguous buffers" 193 range 2 12 194 default 8 195 help 196 DMA mapping framework by default aligns all buffers to the smallest 197 PAGE_SIZE order which is greater than or equal to the requested buffer 198 size. This works well for buffers up to a few hundreds kilobytes, but 199 for larger buffers it just a memory waste. With this parameter you can 200 specify the maximum PAGE_SIZE order for contiguous buffers. Larger 201 buffers will be aligned only to this specified order. The order is 202 expressed as a power of two multiplied by the PAGE_SIZE. 203 204 For example, if your system defaults to 4KiB pages, the order value 205 of 8 means that the buffers will be aligned up to 1MiB only. 206 207 If unsure, leave the default value "8". 208 209endif 210 211config DMA_API_DEBUG 212 bool "Enable debugging of DMA-API usage" 213 select NEED_DMA_MAP_STATE 214 help 215 Enable this option to debug the use of the DMA API by device drivers. 216 With this option you will be able to detect common bugs in device 217 drivers like double-freeing of DMA mappings or freeing mappings that 218 were never allocated. 219 220 This option causes a performance degradation. Use only if you want to 221 debug device drivers and dma interactions. 222 223 If unsure, say N. 224 225config DMA_API_DEBUG_SG 226 bool "Debug DMA scatter-gather usage" 227 default y 228 depends on DMA_API_DEBUG 229 help 230 Perform extra checking that callers of dma_map_sg() have respected the 231 appropriate segment length/boundary limits for the given device when 232 preparing DMA scatterlists. 233 234 This is particularly likely to have been overlooked in cases where the 235 dma_map_sg() API is used for general bulk mapping of pages rather than 236 preparing literal scatter-gather descriptors, where there is a risk of 237 unexpected behaviour from DMA API implementations if the scatterlist 238 is technically out-of-spec. 239 240 If unsure, say N. 241 242config DMA_MAP_BENCHMARK 243 bool "Enable benchmarking of streaming DMA mapping" 244 depends on DEBUG_FS 245 help 246 Provides /sys/kernel/debug/dma_map_benchmark that helps with testing 247 performance of dma_(un)map_page. 248 249 See tools/testing/selftests/dma/dma_map_benchmark.c 250