kernel/dma/Kconfig

   1 # SPDX-License-Identifier: GPL-2.0-only
   2
   3 config NO_DMA
   4         bool
   5
   6 config HAS_DMA
   7         bool
   8         depends on !NO_DMA
   9         default y
  10
  11 config 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 #
  20 config DMA_OPS_BYPASS
  21         bool
  22
  23 # Lets platform IOMMU driver choose between bypass and IOMMU
  24 config ARCH_HAS_DMA_MAP_DIRECT
  25         bool
  26
  27 config NEED_SG_DMA_LENGTH
  28         bool
  29
  30 config NEED_DMA_MAP_STATE
  31         bool
  32
  33 config ARCH_DMA_ADDR_T_64BIT
  34         def_bool 64BIT || PHYS_ADDR_T_64BIT
  35
  36 config 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 #
  45 config ARCH_HAS_DMA_WRITE_COMBINE
  46         bool
  47
  48 #
  49 # Select if the architectures provides the arch_dma_mark_clean hook
  50 #
  51 config ARCH_HAS_DMA_MARK_CLEAN
  52         bool
  53
  54 config DMA_DECLARE_COHERENT
  55         bool
  56
  57 config ARCH_HAS_SETUP_DMA_OPS
  58         bool
  59
  60 config ARCH_HAS_TEARDOWN_DMA_OPS
  61         bool
  62
  63 config ARCH_HAS_SYNC_DMA_FOR_DEVICE
  64         bool
  65
  66 config ARCH_HAS_SYNC_DMA_FOR_CPU
  67         bool
  68         select NEED_DMA_MAP_STATE
  69
  70 config ARCH_HAS_SYNC_DMA_FOR_CPU_ALL
  71         bool
  72
  73 config ARCH_HAS_DMA_PREP_COHERENT
  74         bool
  75
  76 config ARCH_HAS_FORCE_DMA_UNENCRYPTED
  77         bool
  78
  79 config 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 #
  88 config DMA_NONCOHERENT_MMAP
  89         default y if !MMU
  90         bool
  91
  92 config DMA_COHERENT_POOL
  93         select GENERIC_ALLOCATOR
  94         bool
  95
  96 config DMA_REMAP
  97         bool
  98         depends on MMU
  99         select DMA_NONCOHERENT_MMAP
 100
 101 config DMA_DIRECT_REMAP
 102         bool
 103         select DMA_REMAP
 104         select DMA_COHERENT_POOL
 105
 106 config 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
 120 if  DMA_CMA
 121
 122 config 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
 132 comment "Default contiguous memory area size:"
 133
 134 config 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
 145 config 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
 156 choice
 157         prompt "Selected region size"
 158         default CMA_SIZE_SEL_MBYTES
 159
 160 config CMA_SIZE_SEL_MBYTES
 161         bool "Use mega bytes value only"
 162
 163 config CMA_SIZE_SEL_PERCENTAGE
 164         bool "Use percentage value only"
 165
 166 config CMA_SIZE_SEL_MIN
 167         bool "Use lower value (minimum)"
 168
 169 config CMA_SIZE_SEL_MAX
 170         bool "Use higher value (maximum)"
 171
 172 endchoice
 173
 174 config 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
 192 endif
 193
 194 config 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
 208 config 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
 225 config 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