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