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