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_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# 19config DMA_OPS_BYPASS 20 bool 21 22# Lets platform IOMMU driver choose between bypass and IOMMU 23config ARCH_HAS_DMA_MAP_DIRECT 24 bool 25 26config NEED_SG_DMA_FLAGS 27 bool 28 29config NEED_SG_DMA_LENGTH 30 bool 31 32config NEED_DMA_MAP_STATE 33 bool 34 35config ARCH_DMA_ADDR_T_64BIT 36 def_bool 64BIT || PHYS_ADDR_T_64BIT 37 38config 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# 47config ARCH_HAS_DMA_WRITE_COMBINE 48 bool 49 50config DMA_DECLARE_COHERENT 51 bool 52 53config ARCH_HAS_SETUP_DMA_OPS 54 bool 55 56config ARCH_HAS_TEARDOWN_DMA_OPS 57 bool 58 59config ARCH_HAS_SYNC_DMA_FOR_DEVICE 60 bool 61 62config ARCH_HAS_SYNC_DMA_FOR_CPU 63 bool 64 select NEED_DMA_MAP_STATE 65 66config ARCH_HAS_SYNC_DMA_FOR_CPU_ALL 67 bool 68 69config ARCH_HAS_DMA_PREP_COHERENT 70 bool 71 72config ARCH_HAS_FORCE_DMA_UNENCRYPTED 73 bool 74 75config ARCH_HAS_BATCHED_DMA_SYNC 76 bool 77 78# 79# Select this option if the architecture assumes DMA devices are coherent 80# by default. 81# 82config ARCH_DMA_DEFAULT_COHERENT 83 bool 84 85config SWIOTLB 86 bool 87 select NEED_DMA_MAP_STATE 88 89config SWIOTLB_DEFAULT_SIZE_MB 90 int "Default SWIOTLB bounce buffer size in MB" 91 depends on SWIOTLB 92 range 1 64 93 default 64 94 help 95 Sets the default size of the software IO TLB (SWIOTLB) bounce buffer 96 pool allocated at boot time. The default is 64 MB. 97 98 On memory-constrained embedded or mobile platforms (e.g., those with 99 a hardware IOMMU such as ARM SMMU covering most DMA-capable devices), 100 a smaller value such as 4 or 8 MB may be sufficient. The SWIOTLB is 101 then only needed for devices that bypass the IOMMU or have restricted 102 DMA address ranges. 103 104 The minimum allowed value is 1 MB. This compile-time default can be 105 overridden at runtime using the "swiotlb=<nslabs>" kernel command line 106 parameter. Refer to Documentation/admin-guide/kernel-parameters.txt 107 for details. 108 109 If unsure, leave at the default value of 64. 110 111config SWIOTLB_DYNAMIC 112 bool "Dynamic allocation of DMA bounce buffers" 113 default n 114 depends on SWIOTLB 115 help 116 This enables dynamic resizing of the software IO TLB. The kernel 117 starts with one memory pool at boot and it will allocate additional 118 pools as needed. To reduce run-time kernel memory requirements, you 119 may have to specify a smaller size of the initial pool using 120 "swiotlb=" on the kernel command line. 121 122 If unsure, say N. 123 124config DMA_BOUNCE_UNALIGNED_KMALLOC 125 bool 126 depends on SWIOTLB 127 128config DMA_NEED_SYNC 129 def_bool ARCH_HAS_SYNC_DMA_FOR_DEVICE || ARCH_HAS_SYNC_DMA_FOR_CPU || \ 130 ARCH_HAS_SYNC_DMA_FOR_CPU_ALL || DMA_API_DEBUG || \ 131 ARCH_HAS_DMA_OPS || SWIOTLB 132 133config DMA_RESTRICTED_POOL 134 bool "DMA Restricted Pool" 135 depends on OF && OF_RESERVED_MEM && SWIOTLB 136 help 137 This enables support for restricted DMA pools which provide a level of 138 DMA memory protection on systems with limited hardware protection 139 capabilities, such as those lacking an IOMMU. 140 141 For more information see 142 <Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt> 143 and <kernel/dma/swiotlb.c>. 144 If unsure, say "n". 145 146# 147# Should be selected if we can mmap non-coherent mappings to userspace. 148# The only thing that is really required is a way to set an uncached bit 149# in the pagetables 150# 151config DMA_NONCOHERENT_MMAP 152 default y if !MMU 153 bool 154 155config DMA_COHERENT_POOL 156 select GENERIC_ALLOCATOR 157 bool 158 159config DMA_GLOBAL_POOL 160 select DMA_DECLARE_COHERENT 161 depends on !ARCH_HAS_DMA_SET_UNCACHED 162 depends on !DMA_DIRECT_REMAP 163 bool 164 165config DMA_DIRECT_REMAP 166 bool 167 select DMA_COHERENT_POOL 168 select DMA_NONCOHERENT_MMAP 169 170# 171# Fallback to arch code for DMA allocations. This should eventually go away. 172# 173config ARCH_HAS_DMA_ALLOC 174 depends on !ARCH_HAS_DMA_SET_UNCACHED 175 depends on !DMA_DIRECT_REMAP 176 depends on !DMA_GLOBAL_POOL 177 bool 178 179config DMA_CMA 180 bool "DMA Contiguous Memory Allocator" 181 depends on HAVE_DMA_CONTIGUOUS && CMA 182 help 183 This enables the Contiguous Memory Allocator which allows drivers 184 to allocate big physically-contiguous blocks of memory for use with 185 hardware components that do not support I/O map nor scatter-gather. 186 187 You can disable CMA by specifying "cma=0" on the kernel's command 188 line. 189 190 For more information see <kernel/dma/contiguous.c>. 191 If unsure, say "n". 192 193if DMA_CMA 194 195config DMA_NUMA_CMA 196 bool "Enable separate DMA Contiguous Memory Area for NUMA Node" 197 depends on NUMA 198 help 199 Enable this option to get numa CMA areas so that NUMA devices 200 can get local memory by DMA coherent APIs. 201 202 You can set the size of pernuma CMA by specifying "cma_pernuma=size" 203 or set the node id and its size of CMA by specifying "numa_cma= 204 <node>:size[,<node>:size]" on the kernel's command line. And in 205 rare case that the above 2 are both setup, then the "numa_cma=" 206 takes priority for the specified numa nodes. 207 208config CMA_SIZE_PERNUMA 209 bool "Default CMA area per NUMA node" 210 depends on DMA_NUMA_CMA 211 default y 212 help 213 On systems with more than one NUMA node, the selected CMA 214 area size will be also allocated on each additional node, 215 so that most devices may have benefit from better DMA 216 locality without an explicit command-line opt-in. 217 218comment "Default contiguous memory area size:" 219 220config CMA_SIZE_MBYTES 221 int "Size in Mega Bytes" 222 depends on !CMA_SIZE_SEL_PERCENTAGE 223 default 0 if X86 224 default 16 225 help 226 Defines the size (in MiB) of the default memory area for Contiguous 227 Memory Allocator. If the size of 0 is selected, CMA is disabled by 228 default, but it can be enabled by passing cma=size[MG] to the kernel. 229 230 231config CMA_SIZE_PERCENTAGE 232 int "Percentage of total memory" 233 depends on !CMA_SIZE_SEL_MBYTES 234 default 0 if X86 235 default 10 236 help 237 Defines the size of the default memory area for Contiguous Memory 238 Allocator as a percentage of the total memory in the system. 239 If 0 percent is selected, CMA is disabled by default, but it can be 240 enabled by passing cma=size[MG] to the kernel. 241 242choice 243 prompt "Selected region size" 244 default CMA_SIZE_SEL_MBYTES 245 246config CMA_SIZE_SEL_MBYTES 247 bool "Use mega bytes value only" 248 249config CMA_SIZE_SEL_PERCENTAGE 250 bool "Use percentage value only" 251 252config CMA_SIZE_SEL_MIN 253 bool "Use lower value (minimum)" 254 255config CMA_SIZE_SEL_MAX 256 bool "Use higher value (maximum)" 257 258endchoice 259 260config CMA_ALIGNMENT 261 int "Maximum PAGE_SIZE order of alignment for contiguous buffers" 262 range 2 12 263 default 8 264 help 265 DMA mapping framework by default aligns all buffers to the smallest 266 PAGE_SIZE order which is greater than or equal to the requested buffer 267 size. This works well for buffers up to a few hundreds kilobytes, but 268 for larger buffers it just a memory waste. With this parameter you can 269 specify the maximum PAGE_SIZE order for contiguous buffers. Larger 270 buffers will be aligned only to this specified order. The order is 271 expressed as a power of two multiplied by the PAGE_SIZE. 272 273 For example, if your system defaults to 4KiB pages, the order value 274 of 8 means that the buffers will be aligned up to 1MiB only. 275 276 If unsure, leave the default value "8". 277 278endif 279 280config DMA_API_DEBUG 281 bool "Enable debugging of DMA-API usage" 282 select NEED_DMA_MAP_STATE 283 help 284 Enable this option to debug the use of the DMA API by device drivers. 285 With this option you will be able to detect common bugs in device 286 drivers like double-freeing of DMA mappings or freeing mappings that 287 were never allocated. 288 289 This option causes a performance degradation. Use only if you want to 290 debug device drivers and dma interactions. 291 292 If unsure, say N. 293 294config DMA_MAP_BENCHMARK 295 bool "Enable benchmarking of streaming DMA mapping" 296 depends on DEBUG_FS 297 help 298 Provides /sys/kernel/debug/dma_map_benchmark that helps with testing 299 performance of dma_(un)map_page. 300 301 See tools/testing/selftests/dma/dma_map_benchmark.c 302