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 83# 84# Should be selected if we can mmap non-coherent mappings to userspace. 85# The only thing that is really required is a way to set an uncached bit 86# in the pagetables 87# 88config DMA_NONCOHERENT_MMAP 89 default y if !MMU 90 bool 91 92config DMA_COHERENT_POOL 93 select GENERIC_ALLOCATOR 94 bool 95 96config DMA_GLOBAL_POOL 97 select DMA_DECLARE_COHERENT 98 bool 99 100config DMA_REMAP 101 bool 102 depends on MMU 103 select DMA_NONCOHERENT_MMAP 104 105config DMA_DIRECT_REMAP 106 bool 107 select DMA_REMAP 108 select DMA_COHERENT_POOL 109 110config DMA_CMA 111 bool "DMA Contiguous Memory Allocator" 112 depends on HAVE_DMA_CONTIGUOUS && CMA 113 help 114 This enables the Contiguous Memory Allocator which allows drivers 115 to allocate big physically-contiguous blocks of memory for use with 116 hardware components that do not support I/O map nor scatter-gather. 117 118 You can disable CMA by specifying "cma=0" on the kernel's command 119 line. 120 121 For more information see <kernel/dma/contiguous.c>. 122 If unsure, say "n". 123 124if DMA_CMA 125 126config DMA_PERNUMA_CMA 127 bool "Enable separate DMA Contiguous Memory Area for each NUMA Node" 128 default NUMA && ARM64 129 help 130 Enable this option to get pernuma CMA areas so that devices like 131 ARM64 SMMU can get local memory by DMA coherent APIs. 132 133 You can set the size of pernuma CMA by specifying "cma_pernuma=size" 134 on the kernel's command line. 135 136comment "Default contiguous memory area size:" 137 138config CMA_SIZE_MBYTES 139 int "Size in Mega Bytes" 140 depends on !CMA_SIZE_SEL_PERCENTAGE 141 default 0 if X86 142 default 16 143 help 144 Defines the size (in MiB) of the default memory area for Contiguous 145 Memory Allocator. If the size of 0 is selected, CMA is disabled by 146 default, but it can be enabled by passing cma=size[MG] to the kernel. 147 148 149config CMA_SIZE_PERCENTAGE 150 int "Percentage of total memory" 151 depends on !CMA_SIZE_SEL_MBYTES 152 default 0 if X86 153 default 10 154 help 155 Defines the size of the default memory area for Contiguous Memory 156 Allocator as a percentage of the total memory in the system. 157 If 0 percent is selected, CMA is disabled by default, but it can be 158 enabled by passing cma=size[MG] to the kernel. 159 160choice 161 prompt "Selected region size" 162 default CMA_SIZE_SEL_MBYTES 163 164config CMA_SIZE_SEL_MBYTES 165 bool "Use mega bytes value only" 166 167config CMA_SIZE_SEL_PERCENTAGE 168 bool "Use percentage value only" 169 170config CMA_SIZE_SEL_MIN 171 bool "Use lower value (minimum)" 172 173config CMA_SIZE_SEL_MAX 174 bool "Use higher value (maximum)" 175 176endchoice 177 178config CMA_ALIGNMENT 179 int "Maximum PAGE_SIZE order of alignment for contiguous buffers" 180 range 2 12 181 default 8 182 help 183 DMA mapping framework by default aligns all buffers to the smallest 184 PAGE_SIZE order which is greater than or equal to the requested buffer 185 size. This works well for buffers up to a few hundreds kilobytes, but 186 for larger buffers it just a memory waste. With this parameter you can 187 specify the maximum PAGE_SIZE order for contiguous buffers. Larger 188 buffers will be aligned only to this specified order. The order is 189 expressed as a power of two multiplied by the PAGE_SIZE. 190 191 For example, if your system defaults to 4KiB pages, the order value 192 of 8 means that the buffers will be aligned up to 1MiB only. 193 194 If unsure, leave the default value "8". 195 196endif 197 198config DMA_API_DEBUG 199 bool "Enable debugging of DMA-API usage" 200 select NEED_DMA_MAP_STATE 201 help 202 Enable this option to debug the use of the DMA API by device drivers. 203 With this option you will be able to detect common bugs in device 204 drivers like double-freeing of DMA mappings or freeing mappings that 205 were never allocated. 206 207 This option causes a performance degradation. Use only if you want to 208 debug device drivers and dma interactions. 209 210 If unsure, say N. 211 212config DMA_API_DEBUG_SG 213 bool "Debug DMA scatter-gather usage" 214 default y 215 depends on DMA_API_DEBUG 216 help 217 Perform extra checking that callers of dma_map_sg() have respected the 218 appropriate segment length/boundary limits for the given device when 219 preparing DMA scatterlists. 220 221 This is particularly likely to have been overlooked in cases where the 222 dma_map_sg() API is used for general bulk mapping of pages rather than 223 preparing literal scatter-gather descriptors, where there is a risk of 224 unexpected behaviour from DMA API implementations if the scatterlist 225 is technically out-of-spec. 226 227 If unsure, say N. 228 229config DMA_MAP_BENCHMARK 230 bool "Enable benchmarking of streaming DMA mapping" 231 depends on DEBUG_FS 232 help 233 Provides /sys/kernel/debug/dma_map_benchmark that helps with testing 234 performance of dma_(un)map_page. 235 236 See tools/testing/selftests/dma/dma_map_benchmark.c 237