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_FLAGS
28	bool
29
30config NEED_SG_DMA_LENGTH
31	bool
32
33config NEED_DMA_MAP_STATE
34	bool
35
36config ARCH_DMA_ADDR_T_64BIT
37	def_bool 64BIT || PHYS_ADDR_T_64BIT
38
39config ARCH_HAS_DMA_SET_MASK
40	bool
41
42#
43# Select this option if the architecture needs special handling for
44# DMA_ATTR_WRITE_COMBINE.  Normally the "uncached" mapping should be what
45# people think of when saying write combine, so very few platforms should
46# need to enable this.
47#
48config ARCH_HAS_DMA_WRITE_COMBINE
49	bool
50
51#
52# Select if the architectures provides the arch_dma_mark_clean hook
53#
54config ARCH_HAS_DMA_MARK_CLEAN
55	bool
56
57config DMA_DECLARE_COHERENT
58	bool
59
60config ARCH_HAS_SETUP_DMA_OPS
61	bool
62
63config ARCH_HAS_TEARDOWN_DMA_OPS
64	bool
65
66config ARCH_HAS_SYNC_DMA_FOR_DEVICE
67	bool
68
69config ARCH_HAS_SYNC_DMA_FOR_CPU
70	bool
71	select NEED_DMA_MAP_STATE
72
73config ARCH_HAS_SYNC_DMA_FOR_CPU_ALL
74	bool
75
76config ARCH_HAS_DMA_PREP_COHERENT
77	bool
78
79config ARCH_HAS_FORCE_DMA_UNENCRYPTED
80	bool
81
82#
83# Select this option if the architecture assumes DMA devices are coherent
84# by default.
85#
86config ARCH_DMA_DEFAULT_COHERENT
87	bool
88
89config SWIOTLB
90	bool
91	select NEED_DMA_MAP_STATE
92
93config SWIOTLB_DYNAMIC
94	bool "Dynamic allocation of DMA bounce buffers"
95	default n
96	depends on SWIOTLB
97	help
98	  This enables dynamic resizing of the software IO TLB. The kernel
99	  starts with one memory pool at boot and it will allocate additional
100	  pools as needed. To reduce run-time kernel memory requirements, you
101	  may have to specify a smaller size of the initial pool using
102	  "swiotlb=" on the kernel command line.
103
104	  If unsure, say N.
105
106config DMA_BOUNCE_UNALIGNED_KMALLOC
107	bool
108	depends on SWIOTLB
109
110config DMA_RESTRICTED_POOL
111	bool "DMA Restricted Pool"
112	depends on OF && OF_RESERVED_MEM && SWIOTLB
113	help
114	  This enables support for restricted DMA pools which provide a level of
115	  DMA memory protection on systems with limited hardware protection
116	  capabilities, such as those lacking an IOMMU.
117
118	  For more information see
119	  <Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt>
120	  and <kernel/dma/swiotlb.c>.
121	  If unsure, say "n".
122
123#
124# Should be selected if we can mmap non-coherent mappings to userspace.
125# The only thing that is really required is a way to set an uncached bit
126# in the pagetables
127#
128config DMA_NONCOHERENT_MMAP
129	default y if !MMU
130	bool
131
132config DMA_COHERENT_POOL
133	select GENERIC_ALLOCATOR
134	bool
135
136config DMA_GLOBAL_POOL
137	select DMA_DECLARE_COHERENT
138	depends on !ARCH_HAS_DMA_SET_UNCACHED
139	depends on !DMA_DIRECT_REMAP
140	bool
141
142config DMA_DIRECT_REMAP
143	bool
144	select DMA_COHERENT_POOL
145	select DMA_NONCOHERENT_MMAP
146
147#
148# Fallback to arch code for DMA allocations.  This should eventually go away.
149#
150config ARCH_HAS_DMA_ALLOC
151	depends on !ARCH_HAS_DMA_SET_UNCACHED
152	depends on !DMA_DIRECT_REMAP
153	depends on !DMA_GLOBAL_POOL
154	bool
155
156config DMA_CMA
157	bool "DMA Contiguous Memory Allocator"
158	depends on HAVE_DMA_CONTIGUOUS && CMA
159	help
160	  This enables the Contiguous Memory Allocator which allows drivers
161	  to allocate big physically-contiguous blocks of memory for use with
162	  hardware components that do not support I/O map nor scatter-gather.
163
164	  You can disable CMA by specifying "cma=0" on the kernel's command
165	  line.
166
167	  For more information see <kernel/dma/contiguous.c>.
168	  If unsure, say "n".
169
170if  DMA_CMA
171
172config DMA_NUMA_CMA
173	bool "Enable separate DMA Contiguous Memory Area for NUMA Node"
174	depends on NUMA
175	help
176	  Enable this option to get numa CMA areas so that NUMA devices
177	  can get local memory by DMA coherent APIs.
178
179	  You can set the size of pernuma CMA by specifying "cma_pernuma=size"
180	  or set the node id and its size of CMA by specifying "numa_cma=
181	  <node>:size[,<node>:size]" on the kernel's command line.
182
183comment "Default contiguous memory area size:"
184
185config CMA_SIZE_MBYTES
186	int "Size in Mega Bytes"
187	depends on !CMA_SIZE_SEL_PERCENTAGE
188	default 0 if X86
189	default 16
190	help
191	  Defines the size (in MiB) of the default memory area for Contiguous
192	  Memory Allocator.  If the size of 0 is selected, CMA is disabled by
193	  default, but it can be enabled by passing cma=size[MG] to the kernel.
194
195
196config CMA_SIZE_PERCENTAGE
197	int "Percentage of total memory"
198	depends on !CMA_SIZE_SEL_MBYTES
199	default 0 if X86
200	default 10
201	help
202	  Defines the size of the default memory area for Contiguous Memory
203	  Allocator as a percentage of the total memory in the system.
204	  If 0 percent is selected, CMA is disabled by default, but it can be
205	  enabled by passing cma=size[MG] to the kernel.
206
207choice
208	prompt "Selected region size"
209	default CMA_SIZE_SEL_MBYTES
210
211config CMA_SIZE_SEL_MBYTES
212	bool "Use mega bytes value only"
213
214config CMA_SIZE_SEL_PERCENTAGE
215	bool "Use percentage value only"
216
217config CMA_SIZE_SEL_MIN
218	bool "Use lower value (minimum)"
219
220config CMA_SIZE_SEL_MAX
221	bool "Use higher value (maximum)"
222
223endchoice
224
225config CMA_ALIGNMENT
226	int "Maximum PAGE_SIZE order of alignment for contiguous buffers"
227	range 2 12
228	default 8
229	help
230	  DMA mapping framework by default aligns all buffers to the smallest
231	  PAGE_SIZE order which is greater than or equal to the requested buffer
232	  size. This works well for buffers up to a few hundreds kilobytes, but
233	  for larger buffers it just a memory waste. With this parameter you can
234	  specify the maximum PAGE_SIZE order for contiguous buffers. Larger
235	  buffers will be aligned only to this specified order. The order is
236	  expressed as a power of two multiplied by the PAGE_SIZE.
237
238	  For example, if your system defaults to 4KiB pages, the order value
239	  of 8 means that the buffers will be aligned up to 1MiB only.
240
241	  If unsure, leave the default value "8".
242
243endif
244
245config DMA_API_DEBUG
246	bool "Enable debugging of DMA-API usage"
247	select NEED_DMA_MAP_STATE
248	help
249	  Enable this option to debug the use of the DMA API by device drivers.
250	  With this option you will be able to detect common bugs in device
251	  drivers like double-freeing of DMA mappings or freeing mappings that
252	  were never allocated.
253
254	  This option causes a performance degradation.  Use only if you want to
255	  debug device drivers and dma interactions.
256
257	  If unsure, say N.
258
259config DMA_API_DEBUG_SG
260	bool "Debug DMA scatter-gather usage"
261	default y
262	depends on DMA_API_DEBUG
263	help
264	  Perform extra checking that callers of dma_map_sg() have respected the
265	  appropriate segment length/boundary limits for the given device when
266	  preparing DMA scatterlists.
267
268	  This is particularly likely to have been overlooked in cases where the
269	  dma_map_sg() API is used for general bulk mapping of pages rather than
270	  preparing literal scatter-gather descriptors, where there is a risk of
271	  unexpected behaviour from DMA API implementations if the scatterlist
272	  is technically out-of-spec.
273
274	  If unsure, say N.
275
276config DMA_MAP_BENCHMARK
277	bool "Enable benchmarking of streaming DMA mapping"
278	depends on DEBUG_FS
279	help
280	  Provides /sys/kernel/debug/dma_map_benchmark that helps with testing
281	  performance of dma_(un)map_page.
282
283	  See tools/testing/selftests/dma/dma_map_benchmark.c
284