1 # SPDX-License-Identifier: GPL-2.0-only 2 3 config NO_DMA 4 bool 5 6 config HAS_DMA 7 bool 8 depends on !NO_DMA 9 default y 10 11 config DMA_OPS_HELPERS 12 bool 13 14 # 15 # IOMMU drivers that can bypass the IOMMU code and optionally use the direct 16 # mapping fast path should select this option and set the dma_ops_bypass 17 # flag in struct device where applicable 18 # 19 config DMA_OPS_BYPASS 20 bool 21 22 # Lets platform IOMMU driver choose between bypass and IOMMU 23 config ARCH_HAS_DMA_MAP_DIRECT 24 bool 25 26 config NEED_SG_DMA_FLAGS 27 bool 28 29 config NEED_SG_DMA_LENGTH 30 bool 31 32 config NEED_DMA_MAP_STATE 33 bool 34 35 config ARCH_DMA_ADDR_T_64BIT 36 def_bool 64BIT || PHYS_ADDR_T_64BIT 37 38 config ARCH_HAS_DMA_SET_MASK 39 bool 40 41 # 42 # Select this option if the architecture needs special handling for 43 # DMA_ATTR_WRITE_COMBINE. Normally the "uncached" mapping should be what 44 # people think of when saying write combine, so very few platforms should 45 # need to enable this. 46 # 47 config ARCH_HAS_DMA_WRITE_COMBINE 48 bool 49 50 # 51 # Select if the architectures provides the arch_dma_mark_clean hook 52 # 53 config ARCH_HAS_DMA_MARK_CLEAN 54 bool 55 56 config DMA_DECLARE_COHERENT 57 bool 58 59 config ARCH_HAS_SETUP_DMA_OPS 60 bool 61 62 config ARCH_HAS_TEARDOWN_DMA_OPS 63 bool 64 65 config ARCH_HAS_SYNC_DMA_FOR_DEVICE 66 bool 67 68 config ARCH_HAS_SYNC_DMA_FOR_CPU 69 bool 70 select NEED_DMA_MAP_STATE 71 72 config ARCH_HAS_SYNC_DMA_FOR_CPU_ALL 73 bool 74 75 config ARCH_HAS_DMA_PREP_COHERENT 76 bool 77 78 config ARCH_HAS_FORCE_DMA_UNENCRYPTED 79 bool 80 81 # 82 # Select this option if the architecture assumes DMA devices are coherent 83 # by default. 84 # 85 config ARCH_DMA_DEFAULT_COHERENT 86 bool 87 88 config SWIOTLB 89 bool 90 select NEED_DMA_MAP_STATE 91 92 config SWIOTLB_DYNAMIC 93 bool "Dynamic allocation of DMA bounce buffers" 94 default n 95 depends on SWIOTLB 96 help 97 This enables dynamic resizing of the software IO TLB. The kernel 98 starts with one memory pool at boot and it will allocate additional 99 pools as needed. To reduce run-time kernel memory requirements, you 100 may have to specify a smaller size of the initial pool using 101 "swiotlb=" on the kernel command line. 102 103 If unsure, say N. 104 105 config DMA_BOUNCE_UNALIGNED_KMALLOC 106 bool 107 depends on SWIOTLB 108 109 config DMA_NEED_SYNC 110 def_bool ARCH_HAS_SYNC_DMA_FOR_DEVICE || ARCH_HAS_SYNC_DMA_FOR_CPU || \ 111 ARCH_HAS_SYNC_DMA_FOR_CPU_ALL || DMA_API_DEBUG || \ 112 ARCH_HAS_DMA_OPS || SWIOTLB 113 114 config DMA_RESTRICTED_POOL 115 bool "DMA Restricted Pool" 116 depends on OF && OF_RESERVED_MEM && SWIOTLB 117 help 118 This enables support for restricted DMA pools which provide a level of 119 DMA memory protection on systems with limited hardware protection 120 capabilities, such as those lacking an IOMMU. 121 122 For more information see 123 <Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt> 124 and <kernel/dma/swiotlb.c>. 125 If unsure, say "n". 126 127 # 128 # Should be selected if we can mmap non-coherent mappings to userspace. 129 # The only thing that is really required is a way to set an uncached bit 130 # in the pagetables 131 # 132 config DMA_NONCOHERENT_MMAP 133 default y if !MMU 134 bool 135 136 config DMA_COHERENT_POOL 137 select GENERIC_ALLOCATOR 138 bool 139 140 config DMA_GLOBAL_POOL 141 select DMA_DECLARE_COHERENT 142 depends on !ARCH_HAS_DMA_SET_UNCACHED 143 depends on !DMA_DIRECT_REMAP 144 bool 145 146 config DMA_DIRECT_REMAP 147 bool 148 select DMA_COHERENT_POOL 149 select DMA_NONCOHERENT_MMAP 150 151 # 152 # Fallback to arch code for DMA allocations. This should eventually go away. 153 # 154 config ARCH_HAS_DMA_ALLOC 155 depends on !ARCH_HAS_DMA_SET_UNCACHED 156 depends on !DMA_DIRECT_REMAP 157 depends on !DMA_GLOBAL_POOL 158 bool 159 160 config DMA_CMA 161 bool "DMA Contiguous Memory Allocator" 162 depends on HAVE_DMA_CONTIGUOUS && CMA 163 help 164 This enables the Contiguous Memory Allocator which allows drivers 165 to allocate big physically-contiguous blocks of memory for use with 166 hardware components that do not support I/O map nor scatter-gather. 167 168 You can disable CMA by specifying "cma=0" on the kernel's command 169 line. 170 171 For more information see <kernel/dma/contiguous.c>. 172 If unsure, say "n". 173 174 if DMA_CMA 175 176 config DMA_NUMA_CMA 177 bool "Enable separate DMA Contiguous Memory Area for NUMA Node" 178 depends on NUMA 179 help 180 Enable this option to get numa CMA areas so that NUMA devices 181 can get local memory by DMA coherent APIs. 182 183 You can set the size of pernuma CMA by specifying "cma_pernuma=size" 184 or set the node id and its size of CMA by specifying "numa_cma= 185 <node>:size[,<node>:size]" on the kernel's command line. 186 187 comment "Default contiguous memory area size:" 188 189 config CMA_SIZE_MBYTES 190 int "Size in Mega Bytes" 191 depends on !CMA_SIZE_SEL_PERCENTAGE 192 default 0 if X86 193 default 16 194 help 195 Defines the size (in MiB) of the default memory area for Contiguous 196 Memory Allocator. If the size of 0 is selected, CMA is disabled by 197 default, but it can be enabled by passing cma=size[MG] to the kernel. 198 199 200 config CMA_SIZE_PERCENTAGE 201 int "Percentage of total memory" 202 depends on !CMA_SIZE_SEL_MBYTES 203 default 0 if X86 204 default 10 205 help 206 Defines the size of the default memory area for Contiguous Memory 207 Allocator as a percentage of the total memory in the system. 208 If 0 percent is selected, CMA is disabled by default, but it can be 209 enabled by passing cma=size[MG] to the kernel. 210 211 choice 212 prompt "Selected region size" 213 default CMA_SIZE_SEL_MBYTES 214 215 config CMA_SIZE_SEL_MBYTES 216 bool "Use mega bytes value only" 217 218 config CMA_SIZE_SEL_PERCENTAGE 219 bool "Use percentage value only" 220 221 config CMA_SIZE_SEL_MIN 222 bool "Use lower value (minimum)" 223 224 config CMA_SIZE_SEL_MAX 225 bool "Use higher value (maximum)" 226 227 endchoice 228 229 config CMA_ALIGNMENT 230 int "Maximum PAGE_SIZE order of alignment for contiguous buffers" 231 range 2 12 232 default 8 233 help 234 DMA mapping framework by default aligns all buffers to the smallest 235 PAGE_SIZE order which is greater than or equal to the requested buffer 236 size. This works well for buffers up to a few hundreds kilobytes, but 237 for larger buffers it just a memory waste. With this parameter you can 238 specify the maximum PAGE_SIZE order for contiguous buffers. Larger 239 buffers will be aligned only to this specified order. The order is 240 expressed as a power of two multiplied by the PAGE_SIZE. 241 242 For example, if your system defaults to 4KiB pages, the order value 243 of 8 means that the buffers will be aligned up to 1MiB only. 244 245 If unsure, leave the default value "8". 246 247 endif 248 249 config DMA_API_DEBUG 250 bool "Enable debugging of DMA-API usage" 251 select NEED_DMA_MAP_STATE 252 help 253 Enable this option to debug the use of the DMA API by device drivers. 254 With this option you will be able to detect common bugs in device 255 drivers like double-freeing of DMA mappings or freeing mappings that 256 were never allocated. 257 258 This option causes a performance degradation. Use only if you want to 259 debug device drivers and dma interactions. 260 261 If unsure, say N. 262 263 config DMA_API_DEBUG_SG 264 bool "Debug DMA scatter-gather usage" 265 default y 266 depends on DMA_API_DEBUG 267 help 268 Perform extra checking that callers of dma_map_sg() have respected the 269 appropriate segment length/boundary limits for the given device when 270 preparing DMA scatterlists. 271 272 This is particularly likely to have been overlooked in cases where the 273 dma_map_sg() API is used for general bulk mapping of pages rather than 274 preparing literal scatter-gather descriptors, where there is a risk of 275 unexpected behaviour from DMA API implementations if the scatterlist 276 is technically out-of-spec. 277 278 If unsure, say N. 279 280 config DMA_MAP_BENCHMARK 281 bool "Enable benchmarking of streaming DMA mapping" 282 depends on DEBUG_FS 283 help 284 Provides /sys/kernel/debug/dma_map_benchmark that helps with testing 285 performance of dma_(un)map_page. 286 287 See tools/testing/selftests/dma/dma_map_benchmark.c 288