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 83# 84# Should be selected if we can mmap non-coherent mappings to userspace. 85# The only thing that is really required is a way to set an uncached bit 86# in the pagetables 87# 88config DMA_NONCOHERENT_MMAP 89 default y if !MMU 90 bool 91 92config DMA_COHERENT_POOL 93 select GENERIC_ALLOCATOR 94 bool 95 96config DMA_REMAP 97 bool 98 depends on MMU 99 select DMA_NONCOHERENT_MMAP 100 101config DMA_DIRECT_REMAP 102 bool 103 select DMA_REMAP 104 select DMA_COHERENT_POOL 105 106config DMA_CMA 107 bool "DMA Contiguous Memory Allocator" 108 depends on HAVE_DMA_CONTIGUOUS && CMA 109 help 110 This enables the Contiguous Memory Allocator which allows drivers 111 to allocate big physically-contiguous blocks of memory for use with 112 hardware components that do not support I/O map nor scatter-gather. 113 114 You can disable CMA by specifying "cma=0" on the kernel's command 115 line. 116 117 For more information see <kernel/dma/contiguous.c>. 118 If unsure, say "n". 119 120if DMA_CMA 121 122config DMA_PERNUMA_CMA 123 bool "Enable separate DMA Contiguous Memory Area for each NUMA Node" 124 default NUMA && ARM64 125 help 126 Enable this option to get pernuma CMA areas so that devices like 127 ARM64 SMMU can get local memory by DMA coherent APIs. 128 129 You can set the size of pernuma CMA by specifying "cma_pernuma=size" 130 on the kernel's command line. 131 132comment "Default contiguous memory area size:" 133 134config CMA_SIZE_MBYTES 135 int "Size in Mega Bytes" 136 depends on !CMA_SIZE_SEL_PERCENTAGE 137 default 0 if X86 138 default 16 139 help 140 Defines the size (in MiB) of the default memory area for Contiguous 141 Memory Allocator. If the size of 0 is selected, CMA is disabled by 142 default, but it can be enabled by passing cma=size[MG] to the kernel. 143 144 145config CMA_SIZE_PERCENTAGE 146 int "Percentage of total memory" 147 depends on !CMA_SIZE_SEL_MBYTES 148 default 0 if X86 149 default 10 150 help 151 Defines the size of the default memory area for Contiguous Memory 152 Allocator as a percentage of the total memory in the system. 153 If 0 percent is selected, CMA is disabled by default, but it can be 154 enabled by passing cma=size[MG] to the kernel. 155 156choice 157 prompt "Selected region size" 158 default CMA_SIZE_SEL_MBYTES 159 160config CMA_SIZE_SEL_MBYTES 161 bool "Use mega bytes value only" 162 163config CMA_SIZE_SEL_PERCENTAGE 164 bool "Use percentage value only" 165 166config CMA_SIZE_SEL_MIN 167 bool "Use lower value (minimum)" 168 169config CMA_SIZE_SEL_MAX 170 bool "Use higher value (maximum)" 171 172endchoice 173 174config CMA_ALIGNMENT 175 int "Maximum PAGE_SIZE order of alignment for contiguous buffers" 176 range 2 12 177 default 8 178 help 179 DMA mapping framework by default aligns all buffers to the smallest 180 PAGE_SIZE order which is greater than or equal to the requested buffer 181 size. This works well for buffers up to a few hundreds kilobytes, but 182 for larger buffers it just a memory waste. With this parameter you can 183 specify the maximum PAGE_SIZE order for contiguous buffers. Larger 184 buffers will be aligned only to this specified order. The order is 185 expressed as a power of two multiplied by the PAGE_SIZE. 186 187 For example, if your system defaults to 4KiB pages, the order value 188 of 8 means that the buffers will be aligned up to 1MiB only. 189 190 If unsure, leave the default value "8". 191 192endif 193 194config DMA_API_DEBUG 195 bool "Enable debugging of DMA-API usage" 196 select NEED_DMA_MAP_STATE 197 help 198 Enable this option to debug the use of the DMA API by device drivers. 199 With this option you will be able to detect common bugs in device 200 drivers like double-freeing of DMA mappings or freeing mappings that 201 were never allocated. 202 203 This option causes a performance degradation. Use only if you want to 204 debug device drivers and dma interactions. 205 206 If unsure, say N. 207 208config DMA_API_DEBUG_SG 209 bool "Debug DMA scatter-gather usage" 210 default y 211 depends on DMA_API_DEBUG 212 help 213 Perform extra checking that callers of dma_map_sg() have respected the 214 appropriate segment length/boundary limits for the given device when 215 preparing DMA scatterlists. 216 217 This is particularly likely to have been overlooked in cases where the 218 dma_map_sg() API is used for general bulk mapping of pages rather than 219 preparing literal scatter-gather descriptors, where there is a risk of 220 unexpected behaviour from DMA API implementations if the scatterlist 221 is technically out-of-spec. 222 223 If unsure, say N. 224 225config DMA_MAP_BENCHMARK 226 bool "Enable benchmarking of streaming DMA mapping" 227 depends on DEBUG_FS 228 help 229 Provides /sys/kernel/debug/dma_map_benchmark that helps with testing 230 performance of dma_(un)map_page. 231 232 See tools/testing/selftests/dma/dma_map_benchmark.c 233