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 config NEED_SG_DMA_LENGTH
  24         bool
  25
  26 config NEED_DMA_MAP_STATE
  27         bool
  28
  29 config ARCH_DMA_ADDR_T_64BIT
  30         def_bool 64BIT || PHYS_ADDR_T_64BIT
  31
  32 config ARCH_HAS_DMA_COHERENCE_H
  33         bool
  34
  35 config 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 #
  44 config ARCH_HAS_DMA_WRITE_COMBINE
  45         bool
  46
  47 #
  48 # Select if the architectures provides the arch_dma_mark_clean hook
  49 #
  50 config ARCH_HAS_DMA_MARK_CLEAN
  51         bool
  52
  53 config DMA_DECLARE_COHERENT
  54         bool
  55
  56 config ARCH_HAS_SETUP_DMA_OPS
  57         bool
  58
  59 config ARCH_HAS_TEARDOWN_DMA_OPS
  60         bool
  61
  62 config ARCH_HAS_SYNC_DMA_FOR_DEVICE
  63         bool
  64
  65 config ARCH_HAS_SYNC_DMA_FOR_CPU
  66         bool
  67         select NEED_DMA_MAP_STATE
  68
  69 config ARCH_HAS_SYNC_DMA_FOR_CPU_ALL
  70         bool
  71
  72 config ARCH_HAS_DMA_PREP_COHERENT
  73         bool
  74
  75 config ARCH_HAS_FORCE_DMA_UNENCRYPTED
  76         bool
  77
  78 config DMA_VIRT_OPS
  79         bool
  80         depends on HAS_DMA
  81         select DMA_OPS
  82
  83 config SWIOTLB
  84         bool
  85         select NEED_DMA_MAP_STATE
  86
  87 #
  88 # Should be selected if we can mmap non-coherent mappings to userspace.
  89 # The only thing that is really required is a way to set an uncached bit
  90 # in the pagetables
  91 #
  92 config DMA_NONCOHERENT_MMAP
  93         default y if !MMU
  94         bool
  95
  96 config DMA_COHERENT_POOL
  97         select GENERIC_ALLOCATOR
  98         bool
  99
 100 config DMA_REMAP
 101         bool
 102         depends on MMU
 103         select DMA_NONCOHERENT_MMAP
 104
 105 config DMA_DIRECT_REMAP
 106         bool
 107         select DMA_REMAP
 108         select DMA_COHERENT_POOL
 109
 110 config DMA_CMA
 111         bool "DMA Contiguous Memory Allocator"
 112         depends on HAVE_DMA_CONTIGUOUS && CMA
 113         help
 114           This enables the Contiguous Memory Allocator which allows drivers
 115           to allocate big physically-contiguous blocks of memory for use with
 116           hardware components that do not support I/O map nor scatter-gather.
 117
 118           You can disable CMA by specifying "cma=0" on the kernel's command
 119           line.
 120
 121           For more information see <kernel/dma/contiguous.c>.
 122           If unsure, say "n".
 123
 124 if  DMA_CMA
 125
 126 config DMA_PERNUMA_CMA
 127         bool "Enable separate DMA Contiguous Memory Area for each NUMA Node"
 128         default NUMA && ARM64
 129         help
 130           Enable this option to get pernuma CMA areas so that devices like
 131           ARM64 SMMU can get local memory by DMA coherent APIs.
 132
 133           You can set the size of pernuma CMA by specifying "cma_pernuma=size"
 134           on the kernel's command line.
 135
 136 comment "Default contiguous memory area size:"
 137
 138 config CMA_SIZE_MBYTES
 139         int "Size in Mega Bytes"
 140         depends on !CMA_SIZE_SEL_PERCENTAGE
 141         default 0 if X86
 142         default 16
 143         help
 144           Defines the size (in MiB) of the default memory area for Contiguous
 145           Memory Allocator.  If the size of 0 is selected, CMA is disabled by
 146           default, but it can be enabled by passing cma=size[MG] to the kernel.
 147
 148
 149 config CMA_SIZE_PERCENTAGE
 150         int "Percentage of total memory"
 151         depends on !CMA_SIZE_SEL_MBYTES
 152         default 0 if X86
 153         default 10
 154         help
 155           Defines the size of the default memory area for Contiguous Memory
 156           Allocator as a percentage of the total memory in the system.
 157           If 0 percent is selected, CMA is disabled by default, but it can be
 158           enabled by passing cma=size[MG] to the kernel.
 159
 160 choice
 161         prompt "Selected region size"
 162         default CMA_SIZE_SEL_MBYTES
 163
 164 config CMA_SIZE_SEL_MBYTES
 165         bool "Use mega bytes value only"
 166
 167 config CMA_SIZE_SEL_PERCENTAGE
 168         bool "Use percentage value only"
 169
 170 config CMA_SIZE_SEL_MIN
 171         bool "Use lower value (minimum)"
 172
 173 config CMA_SIZE_SEL_MAX
 174         bool "Use higher value (maximum)"
 175
 176 endchoice
 177
 178 config CMA_ALIGNMENT
 179         int "Maximum PAGE_SIZE order of alignment for contiguous buffers"
 180         range 2 12
 181         default 8
 182         help
 183           DMA mapping framework by default aligns all buffers to the smallest
 184           PAGE_SIZE order which is greater than or equal to the requested buffer
 185           size. This works well for buffers up to a few hundreds kilobytes, but
 186           for larger buffers it just a memory waste. With this parameter you can
 187           specify the maximum PAGE_SIZE order for contiguous buffers. Larger
 188           buffers will be aligned only to this specified order. The order is
 189           expressed as a power of two multiplied by the PAGE_SIZE.
 190
 191           For example, if your system defaults to 4KiB pages, the order value
 192           of 8 means that the buffers will be aligned up to 1MiB only.
 193
 194           If unsure, leave the default value "8".
 195
 196 endif
 197
 198 config DMA_API_DEBUG
 199         bool "Enable debugging of DMA-API usage"
 200         select NEED_DMA_MAP_STATE
 201         help
 202           Enable this option to debug the use of the DMA API by device drivers.
 203           With this option you will be able to detect common bugs in device
 204           drivers like double-freeing of DMA mappings or freeing mappings that
 205           were never allocated.
 206
 207           This option causes a performance degradation.  Use only if you want to
 208           debug device drivers and dma interactions.
 209
 210           If unsure, say N.
 211
 212 config DMA_API_DEBUG_SG
 213         bool "Debug DMA scatter-gather usage"
 214         default y
 215         depends on DMA_API_DEBUG
 216         help
 217           Perform extra checking that callers of dma_map_sg() have respected the
 218           appropriate segment length/boundary limits for the given device when
 219           preparing DMA scatterlists.
 220
 221           This is particularly likely to have been overlooked in cases where the
 222           dma_map_sg() API is used for general bulk mapping of pages rather than
 223           preparing literal scatter-gather descriptors, where there is a risk of
 224           unexpected behaviour from DMA API implementations if the scatterlist
 225           is technically out-of-spec.
 226
 227           If unsure, say N.