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