1 # SPDX-License-Identifier: GPL-2.0-only
8 config NEED_SG_DMA_LENGTH
11 config NEED_DMA_MAP_STATE
14 config ARCH_DMA_ADDR_T_64BIT
15 def_bool 64BIT || PHYS_ADDR_T_64BIT
17 config ARCH_HAS_DMA_COHERENCE_H
20 config ARCH_HAS_DMA_SET_MASK
23 config DMA_DECLARE_COHERENT
26 config ARCH_HAS_SETUP_DMA_OPS
29 config ARCH_HAS_TEARDOWN_DMA_OPS
32 config ARCH_HAS_SYNC_DMA_FOR_DEVICE
35 config ARCH_HAS_SYNC_DMA_FOR_CPU
37 select NEED_DMA_MAP_STATE
39 config ARCH_HAS_SYNC_DMA_FOR_CPU_ALL
42 config ARCH_HAS_DMA_PREP_COHERENT
45 config ARCH_HAS_DMA_COHERENT_TO_PFN
48 config ARCH_HAS_DMA_MMAP_PGPROT
51 config ARCH_HAS_FORCE_DMA_UNENCRYPTED
54 config DMA_NONCOHERENT_CACHE_SYNC
63 select NEED_DMA_MAP_STATE
67 select GENERIC_ALLOCATOR
70 config DMA_DIRECT_REMAP
75 bool "DMA Contiguous Memory Allocator"
76 depends on HAVE_DMA_CONTIGUOUS && CMA
78 This enables the Contiguous Memory Allocator which allows drivers
79 to allocate big physically-contiguous blocks of memory for use with
80 hardware components that do not support I/O map nor scatter-gather.
82 You can disable CMA by specifying "cma=0" on the kernel's command
85 For more information see <include/linux/dma-contiguous.h>.
89 comment "Default contiguous memory area size:"
91 config CMA_SIZE_MBYTES
92 int "Size in Mega Bytes"
93 depends on !CMA_SIZE_SEL_PERCENTAGE
97 Defines the size (in MiB) of the default memory area for Contiguous
98 Memory Allocator. If the size of 0 is selected, CMA is disabled by
99 default, but it can be enabled by passing cma=size[MG] to the kernel.
102 config CMA_SIZE_PERCENTAGE
103 int "Percentage of total memory"
104 depends on !CMA_SIZE_SEL_MBYTES
108 Defines the size of the default memory area for Contiguous Memory
109 Allocator as a percentage of the total memory in the system.
110 If 0 percent is selected, CMA is disabled by default, but it can be
111 enabled by passing cma=size[MG] to the kernel.
114 prompt "Selected region size"
115 default CMA_SIZE_SEL_MBYTES
117 config CMA_SIZE_SEL_MBYTES
118 bool "Use mega bytes value only"
120 config CMA_SIZE_SEL_PERCENTAGE
121 bool "Use percentage value only"
123 config CMA_SIZE_SEL_MIN
124 bool "Use lower value (minimum)"
126 config CMA_SIZE_SEL_MAX
127 bool "Use higher value (maximum)"
132 int "Maximum PAGE_SIZE order of alignment for contiguous buffers"
136 DMA mapping framework by default aligns all buffers to the smallest
137 PAGE_SIZE order which is greater than or equal to the requested buffer
138 size. This works well for buffers up to a few hundreds kilobytes, but
139 for larger buffers it just a memory waste. With this parameter you can
140 specify the maximum PAGE_SIZE order for contiguous buffers. Larger
141 buffers will be aligned only to this specified order. The order is
142 expressed as a power of two multiplied by the PAGE_SIZE.
144 For example, if your system defaults to 4KiB pages, the order value
145 of 8 means that the buffers will be aligned up to 1MiB only.
147 If unsure, leave the default value "8".
152 bool "Enable debugging of DMA-API usage"
153 select NEED_DMA_MAP_STATE
155 Enable this option to debug the use of the DMA API by device drivers.
156 With this option you will be able to detect common bugs in device
157 drivers like double-freeing of DMA mappings or freeing mappings that
158 were never allocated.
160 This also attempts to catch cases where a page owned by DMA is
161 accessed by the cpu in a way that could cause data corruption. For
162 example, this enables cow_user_page() to check that the source page is
165 This option causes a performance degradation. Use only if you want to
166 debug device drivers and dma interactions.
170 config DMA_API_DEBUG_SG
171 bool "Debug DMA scatter-gather usage"
173 depends on DMA_API_DEBUG
175 Perform extra checking that callers of dma_map_sg() have respected the
176 appropriate segment length/boundary limits for the given device when
177 preparing DMA scatterlists.
179 This is particularly likely to have been overlooked in cases where the
180 dma_map_sg() API is used for general bulk mapping of pages rather than
181 preparing literal scatter-gather descriptors, where there is a risk of
182 unexpected behaviour from DMA API implementations if the scatterlist
183 is technically out-of-spec.