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_COHERENCE_H 37 bool 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 thing 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 82config SWIOTLB 83 bool 84 select NEED_DMA_MAP_STATE 85 86# 87# Should be selected if we can mmap non-coherent mappings to userspace. 88# The only thing that is really required is a way to set an uncached bit 89# in the pagetables 90# 91config DMA_NONCOHERENT_MMAP 92 default y if !MMU 93 bool 94 95config DMA_COHERENT_POOL 96 select GENERIC_ALLOCATOR 97 bool 98 99config DMA_REMAP 100 bool 101 depends on MMU 102 select DMA_NONCOHERENT_MMAP 103 104config DMA_DIRECT_REMAP 105 bool 106 select DMA_REMAP 107 select DMA_COHERENT_POOL 108 109config DMA_CMA 110 bool "DMA Contiguous Memory Allocator" 111 depends on HAVE_DMA_CONTIGUOUS && CMA 112 help 113 This enables the Contiguous Memory Allocator which allows drivers 114 to allocate big physically-contiguous blocks of memory for use with 115 hardware components that do not support I/O map nor scatter-gather. 116 117 You can disable CMA by specifying "cma=0" on the kernel's command 118 line. 119 120 For more information see <kernel/dma/contiguous.c>. 121 If unsure, say "n". 122 123if DMA_CMA 124 125config DMA_PERNUMA_CMA 126 bool "Enable separate DMA Contiguous Memory Area for each NUMA Node" 127 default NUMA && ARM64 128 help 129 Enable this option to get pernuma CMA areas so that devices like 130 ARM64 SMMU can get local memory by DMA coherent APIs. 131 132 You can set the size of pernuma CMA by specifying "cma_pernuma=size" 133 on the kernel's command line. 134 135comment "Default contiguous memory area size:" 136 137config CMA_SIZE_MBYTES 138 int "Size in Mega Bytes" 139 depends on !CMA_SIZE_SEL_PERCENTAGE 140 default 0 if X86 141 default 16 142 help 143 Defines the size (in MiB) of the default memory area for Contiguous 144 Memory Allocator. If the size of 0 is selected, CMA is disabled by 145 default, but it can be enabled by passing cma=size[MG] to the kernel. 146 147 148config CMA_SIZE_PERCENTAGE 149 int "Percentage of total memory" 150 depends on !CMA_SIZE_SEL_MBYTES 151 default 0 if X86 152 default 10 153 help 154 Defines the size of the default memory area for Contiguous Memory 155 Allocator as a percentage of the total memory in the system. 156 If 0 percent is selected, CMA is disabled by default, but it can be 157 enabled by passing cma=size[MG] to the kernel. 158 159choice 160 prompt "Selected region size" 161 default CMA_SIZE_SEL_MBYTES 162 163config CMA_SIZE_SEL_MBYTES 164 bool "Use mega bytes value only" 165 166config CMA_SIZE_SEL_PERCENTAGE 167 bool "Use percentage value only" 168 169config CMA_SIZE_SEL_MIN 170 bool "Use lower value (minimum)" 171 172config CMA_SIZE_SEL_MAX 173 bool "Use higher value (maximum)" 174 175endchoice 176 177config CMA_ALIGNMENT 178 int "Maximum PAGE_SIZE order of alignment for contiguous buffers" 179 range 2 12 180 default 8 181 help 182 DMA mapping framework by default aligns all buffers to the smallest 183 PAGE_SIZE order which is greater than or equal to the requested buffer 184 size. This works well for buffers up to a few hundreds kilobytes, but 185 for larger buffers it just a memory waste. With this parameter you can 186 specify the maximum PAGE_SIZE order for contiguous buffers. Larger 187 buffers will be aligned only to this specified order. The order is 188 expressed as a power of two multiplied by the PAGE_SIZE. 189 190 For example, if your system defaults to 4KiB pages, the order value 191 of 8 means that the buffers will be aligned up to 1MiB only. 192 193 If unsure, leave the default value "8". 194 195endif 196 197config DMA_API_DEBUG 198 bool "Enable debugging of DMA-API usage" 199 select NEED_DMA_MAP_STATE 200 help 201 Enable this option to debug the use of the DMA API by device drivers. 202 With this option you will be able to detect common bugs in device 203 drivers like double-freeing of DMA mappings or freeing mappings that 204 were never allocated. 205 206 This option causes a performance degradation. Use only if you want to 207 debug device drivers and dma interactions. 208 209 If unsure, say N. 210 211config DMA_API_DEBUG_SG 212 bool "Debug DMA scatter-gather usage" 213 default y 214 depends on DMA_API_DEBUG 215 help 216 Perform extra checking that callers of dma_map_sg() have respected the 217 appropriate segment length/boundary limits for the given device when 218 preparing DMA scatterlists. 219 220 This is particularly likely to have been overlooked in cases where the 221 dma_map_sg() API is used for general bulk mapping of pages rather than 222 preparing literal scatter-gather descriptors, where there is a risk of 223 unexpected behaviour from DMA API implementations if the scatterlist 224 is technically out-of-spec. 225 226 If unsure, say N. 227 228config DMA_MAP_BENCHMARK 229 bool "Enable benchmarking of streaming DMA mapping" 230 depends on DEBUG_FS 231 help 232 Provides /sys/kernel/debug/dma_map_benchmark that helps with testing 233 performance of dma_(un)map_page. 234 235 See tools/testing/selftests/dma/dma_map_benchmark.c 236