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 23config NEED_SG_DMA_LENGTH 24 bool 25 26config NEED_DMA_MAP_STATE 27 bool 28 29config ARCH_DMA_ADDR_T_64BIT 30 def_bool 64BIT || PHYS_ADDR_T_64BIT 31 32config ARCH_HAS_DMA_COHERENCE_H 33 bool 34 35config ARCH_HAS_DMA_SET_MASK 36 bool 37 38# 39# Select this option if the architecture needs special handling for 40# DMA_ATTR_WRITE_COMBINE. Normally the "uncached" mapping should be what 41# people thing of when saying write combine, so very few platforms should 42# need to enable this. 43# 44config ARCH_HAS_DMA_WRITE_COMBINE 45 bool 46 47# 48# Select if the architectures provides the arch_dma_mark_clean hook 49# 50config ARCH_HAS_DMA_MARK_CLEAN 51 bool 52 53config DMA_DECLARE_COHERENT 54 bool 55 56config ARCH_HAS_SETUP_DMA_OPS 57 bool 58 59config ARCH_HAS_TEARDOWN_DMA_OPS 60 bool 61 62config ARCH_HAS_SYNC_DMA_FOR_DEVICE 63 bool 64 65config ARCH_HAS_SYNC_DMA_FOR_CPU 66 bool 67 select NEED_DMA_MAP_STATE 68 69config ARCH_HAS_SYNC_DMA_FOR_CPU_ALL 70 bool 71 72config ARCH_HAS_DMA_PREP_COHERENT 73 bool 74 75config ARCH_HAS_FORCE_DMA_UNENCRYPTED 76 bool 77 78config DMA_NONCOHERENT_CACHE_SYNC 79 bool 80 81config DMA_VIRT_OPS 82 bool 83 depends on HAS_DMA 84 select DMA_OPS 85 86config SWIOTLB 87 bool 88 select NEED_DMA_MAP_STATE 89 90# 91# Should be selected if we can mmap non-coherent mappings to userspace. 92# The only thing that is really required is a way to set an uncached bit 93# in the pagetables 94# 95config DMA_NONCOHERENT_MMAP 96 default y if !MMU 97 bool 98 99config DMA_COHERENT_POOL 100 select GENERIC_ALLOCATOR 101 bool 102 103config DMA_REMAP 104 bool 105 depends on MMU 106 select DMA_NONCOHERENT_MMAP 107 108config DMA_DIRECT_REMAP 109 bool 110 select DMA_REMAP 111 select DMA_COHERENT_POOL 112 113config DMA_CMA 114 bool "DMA Contiguous Memory Allocator" 115 depends on HAVE_DMA_CONTIGUOUS && CMA 116 help 117 This enables the Contiguous Memory Allocator which allows drivers 118 to allocate big physically-contiguous blocks of memory for use with 119 hardware components that do not support I/O map nor scatter-gather. 120 121 You can disable CMA by specifying "cma=0" on the kernel's command 122 line. 123 124 For more information see <include/linux/dma-contiguous.h>. 125 If unsure, say "n". 126 127if DMA_CMA 128 129config DMA_PERNUMA_CMA 130 bool "Enable separate DMA Contiguous Memory Area for each NUMA Node" 131 default NUMA && ARM64 132 help 133 Enable this option to get pernuma CMA areas so that devices like 134 ARM64 SMMU can get local memory by DMA coherent APIs. 135 136 You can set the size of pernuma CMA by specifying "cma_pernuma=size" 137 on the kernel's command line. 138 139comment "Default contiguous memory area size:" 140 141config CMA_SIZE_MBYTES 142 int "Size in Mega Bytes" 143 depends on !CMA_SIZE_SEL_PERCENTAGE 144 default 0 if X86 145 default 16 146 help 147 Defines the size (in MiB) of the default memory area for Contiguous 148 Memory Allocator. If the size of 0 is selected, CMA is disabled by 149 default, but it can be enabled by passing cma=size[MG] to the kernel. 150 151 152config CMA_SIZE_PERCENTAGE 153 int "Percentage of total memory" 154 depends on !CMA_SIZE_SEL_MBYTES 155 default 0 if X86 156 default 10 157 help 158 Defines the size of the default memory area for Contiguous Memory 159 Allocator as a percentage of the total memory in the system. 160 If 0 percent is selected, CMA is disabled by default, but it can be 161 enabled by passing cma=size[MG] to the kernel. 162 163choice 164 prompt "Selected region size" 165 default CMA_SIZE_SEL_MBYTES 166 167config CMA_SIZE_SEL_MBYTES 168 bool "Use mega bytes value only" 169 170config CMA_SIZE_SEL_PERCENTAGE 171 bool "Use percentage value only" 172 173config CMA_SIZE_SEL_MIN 174 bool "Use lower value (minimum)" 175 176config CMA_SIZE_SEL_MAX 177 bool "Use higher value (maximum)" 178 179endchoice 180 181config CMA_ALIGNMENT 182 int "Maximum PAGE_SIZE order of alignment for contiguous buffers" 183 range 4 12 184 default 8 185 help 186 DMA mapping framework by default aligns all buffers to the smallest 187 PAGE_SIZE order which is greater than or equal to the requested buffer 188 size. This works well for buffers up to a few hundreds kilobytes, but 189 for larger buffers it just a memory waste. With this parameter you can 190 specify the maximum PAGE_SIZE order for contiguous buffers. Larger 191 buffers will be aligned only to this specified order. The order is 192 expressed as a power of two multiplied by the PAGE_SIZE. 193 194 For example, if your system defaults to 4KiB pages, the order value 195 of 8 means that the buffers will be aligned up to 1MiB only. 196 197 If unsure, leave the default value "8". 198 199endif 200 201config DMA_API_DEBUG 202 bool "Enable debugging of DMA-API usage" 203 select NEED_DMA_MAP_STATE 204 help 205 Enable this option to debug the use of the DMA API by device drivers. 206 With this option you will be able to detect common bugs in device 207 drivers like double-freeing of DMA mappings or freeing mappings that 208 were never allocated. 209 210 This option causes a performance degradation. Use only if you want to 211 debug device drivers and dma interactions. 212 213 If unsure, say N. 214 215config DMA_API_DEBUG_SG 216 bool "Debug DMA scatter-gather usage" 217 default y 218 depends on DMA_API_DEBUG 219 help 220 Perform extra checking that callers of dma_map_sg() have respected the 221 appropriate segment length/boundary limits for the given device when 222 preparing DMA scatterlists. 223 224 This is particularly likely to have been overlooked in cases where the 225 dma_map_sg() API is used for general bulk mapping of pages rather than 226 preparing literal scatter-gather descriptors, where there is a risk of 227 unexpected behaviour from DMA API implementations if the scatterlist 228 is technically out-of-spec. 229 230 If unsure, say N. 231