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_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#
45config ARCH_HAS_DMA_WRITE_COMBINE
46	bool
47
48#
49# Select if the architectures provides the arch_dma_mark_clean hook
50#
51config ARCH_HAS_DMA_MARK_CLEAN
52	bool
53
54config DMA_DECLARE_COHERENT
55	bool
56
57config ARCH_HAS_SETUP_DMA_OPS
58	bool
59
60config ARCH_HAS_TEARDOWN_DMA_OPS
61	bool
62
63config ARCH_HAS_SYNC_DMA_FOR_DEVICE
64	bool
65
66config ARCH_HAS_SYNC_DMA_FOR_CPU
67	bool
68	select NEED_DMA_MAP_STATE
69
70config ARCH_HAS_SYNC_DMA_FOR_CPU_ALL
71	bool
72
73config ARCH_HAS_DMA_PREP_COHERENT
74	bool
75
76config ARCH_HAS_FORCE_DMA_UNENCRYPTED
77	bool
78
79config SWIOTLB
80	bool
81	select NEED_DMA_MAP_STATE
82
83config DMA_RESTRICTED_POOL
84	bool "DMA Restricted Pool"
85	depends on OF && OF_RESERVED_MEM && SWIOTLB
86	help
87	  This enables support for restricted DMA pools which provide a level of
88	  DMA memory protection on systems with limited hardware protection
89	  capabilities, such as those lacking an IOMMU.
90
91	  For more information see
92	  <Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt>
93	  and <kernel/dma/swiotlb.c>.
94	  If unsure, say "n".
95
96#
97# Should be selected if we can mmap non-coherent mappings to userspace.
98# The only thing that is really required is a way to set an uncached bit
99# in the pagetables
100#
101config DMA_NONCOHERENT_MMAP
102	default y if !MMU
103	bool
104
105config DMA_COHERENT_POOL
106	select GENERIC_ALLOCATOR
107	bool
108
109config DMA_GLOBAL_POOL
110	select DMA_DECLARE_COHERENT
111	bool
112
113config DMA_REMAP
114	bool
115	depends on MMU
116	select DMA_NONCOHERENT_MMAP
117
118config DMA_DIRECT_REMAP
119	bool
120	select DMA_REMAP
121	select DMA_COHERENT_POOL
122
123config DMA_CMA
124	bool "DMA Contiguous Memory Allocator"
125	depends on HAVE_DMA_CONTIGUOUS && CMA
126	help
127	  This enables the Contiguous Memory Allocator which allows drivers
128	  to allocate big physically-contiguous blocks of memory for use with
129	  hardware components that do not support I/O map nor scatter-gather.
130
131	  You can disable CMA by specifying "cma=0" on the kernel's command
132	  line.
133
134	  For more information see <kernel/dma/contiguous.c>.
135	  If unsure, say "n".
136
137if  DMA_CMA
138
139config DMA_PERNUMA_CMA
140	bool "Enable separate DMA Contiguous Memory Area for each NUMA Node"
141	default NUMA && ARM64
142	help
143	  Enable this option to get pernuma CMA areas so that devices like
144	  ARM64 SMMU can get local memory by DMA coherent APIs.
145
146	  You can set the size of pernuma CMA by specifying "cma_pernuma=size"
147	  on the kernel's command line.
148
149comment "Default contiguous memory area size:"
150
151config CMA_SIZE_MBYTES
152	int "Size in Mega Bytes"
153	depends on !CMA_SIZE_SEL_PERCENTAGE
154	default 0 if X86
155	default 16
156	help
157	  Defines the size (in MiB) of the default memory area for Contiguous
158	  Memory Allocator.  If the size of 0 is selected, CMA is disabled by
159	  default, but it can be enabled by passing cma=size[MG] to the kernel.
160
161
162config CMA_SIZE_PERCENTAGE
163	int "Percentage of total memory"
164	depends on !CMA_SIZE_SEL_MBYTES
165	default 0 if X86
166	default 10
167	help
168	  Defines the size of the default memory area for Contiguous Memory
169	  Allocator as a percentage of the total memory in the system.
170	  If 0 percent is selected, CMA is disabled by default, but it can be
171	  enabled by passing cma=size[MG] to the kernel.
172
173choice
174	prompt "Selected region size"
175	default CMA_SIZE_SEL_MBYTES
176
177config CMA_SIZE_SEL_MBYTES
178	bool "Use mega bytes value only"
179
180config CMA_SIZE_SEL_PERCENTAGE
181	bool "Use percentage value only"
182
183config CMA_SIZE_SEL_MIN
184	bool "Use lower value (minimum)"
185
186config CMA_SIZE_SEL_MAX
187	bool "Use higher value (maximum)"
188
189endchoice
190
191config CMA_ALIGNMENT
192	int "Maximum PAGE_SIZE order of alignment for contiguous buffers"
193	range 2 12
194	default 8
195	help
196	  DMA mapping framework by default aligns all buffers to the smallest
197	  PAGE_SIZE order which is greater than or equal to the requested buffer
198	  size. This works well for buffers up to a few hundreds kilobytes, but
199	  for larger buffers it just a memory waste. With this parameter you can
200	  specify the maximum PAGE_SIZE order for contiguous buffers. Larger
201	  buffers will be aligned only to this specified order. The order is
202	  expressed as a power of two multiplied by the PAGE_SIZE.
203
204	  For example, if your system defaults to 4KiB pages, the order value
205	  of 8 means that the buffers will be aligned up to 1MiB only.
206
207	  If unsure, leave the default value "8".
208
209endif
210
211config DMA_API_DEBUG
212	bool "Enable debugging of DMA-API usage"
213	select NEED_DMA_MAP_STATE
214	help
215	  Enable this option to debug the use of the DMA API by device drivers.
216	  With this option you will be able to detect common bugs in device
217	  drivers like double-freeing of DMA mappings or freeing mappings that
218	  were never allocated.
219
220	  This option causes a performance degradation.  Use only if you want to
221	  debug device drivers and dma interactions.
222
223	  If unsure, say N.
224
225config DMA_API_DEBUG_SG
226	bool "Debug DMA scatter-gather usage"
227	default y
228	depends on DMA_API_DEBUG
229	help
230	  Perform extra checking that callers of dma_map_sg() have respected the
231	  appropriate segment length/boundary limits for the given device when
232	  preparing DMA scatterlists.
233
234	  This is particularly likely to have been overlooked in cases where the
235	  dma_map_sg() API is used for general bulk mapping of pages rather than
236	  preparing literal scatter-gather descriptors, where there is a risk of
237	  unexpected behaviour from DMA API implementations if the scatterlist
238	  is technically out-of-spec.
239
240	  If unsure, say N.
241
242config DMA_MAP_BENCHMARK
243	bool "Enable benchmarking of streaming DMA mapping"
244	depends on DEBUG_FS
245	help
246	  Provides /sys/kernel/debug/dma_map_benchmark that helps with testing
247	  performance of dma_(un)map_page.
248
249	  See tools/testing/selftests/dma/dma_map_benchmark.c
250