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