1# SPDX-License-Identifier: GPL-2.0-only
2
3config HAS_DMA
4	bool
5	depends on !NO_DMA
6	default y
7
8config NEED_SG_DMA_LENGTH
9	bool
10
11config NEED_DMA_MAP_STATE
12	bool
13
14config ARCH_DMA_ADDR_T_64BIT
15	def_bool 64BIT || PHYS_ADDR_T_64BIT
16
17config ARCH_HAS_DMA_COHERENCE_H
18	bool
19
20config ARCH_HAS_DMA_SET_MASK
21	bool
22
23#
24# Select this option if the architecture needs special handling for
25# DMA_ATTR_WRITE_COMBINE.  Normally the "uncached" mapping should be what
26# people thing of when saying write combine, so very few platforms should
27# need to enable this.
28#
29config ARCH_HAS_DMA_WRITE_COMBINE
30	bool
31
32config DMA_DECLARE_COHERENT
33	bool
34
35config ARCH_HAS_SETUP_DMA_OPS
36	bool
37
38config ARCH_HAS_TEARDOWN_DMA_OPS
39	bool
40
41config ARCH_HAS_SYNC_DMA_FOR_DEVICE
42	bool
43
44config ARCH_HAS_SYNC_DMA_FOR_CPU
45	bool
46	select NEED_DMA_MAP_STATE
47
48config ARCH_HAS_SYNC_DMA_FOR_CPU_ALL
49	bool
50
51config ARCH_HAS_DMA_PREP_COHERENT
52	bool
53
54config ARCH_HAS_DMA_COHERENT_TO_PFN
55	bool
56
57config ARCH_HAS_FORCE_DMA_UNENCRYPTED
58	bool
59
60config DMA_NONCOHERENT_CACHE_SYNC
61	bool
62
63config DMA_VIRT_OPS
64	bool
65	depends on HAS_DMA
66
67config SWIOTLB
68	bool
69	select NEED_DMA_MAP_STATE
70
71config DMA_REMAP
72	depends on MMU
73	select GENERIC_ALLOCATOR
74	bool
75
76config DMA_DIRECT_REMAP
77	bool
78	select DMA_REMAP
79
80config DMA_CMA
81	bool "DMA Contiguous Memory Allocator"
82	depends on HAVE_DMA_CONTIGUOUS && CMA
83	help
84	  This enables the Contiguous Memory Allocator which allows drivers
85	  to allocate big physically-contiguous blocks of memory for use with
86	  hardware components that do not support I/O map nor scatter-gather.
87
88	  You can disable CMA by specifying "cma=0" on the kernel's command
89	  line.
90
91	  For more information see <include/linux/dma-contiguous.h>.
92	  If unsure, say "n".
93
94if  DMA_CMA
95comment "Default contiguous memory area size:"
96
97config CMA_SIZE_MBYTES
98	int "Size in Mega Bytes"
99	depends on !CMA_SIZE_SEL_PERCENTAGE
100	default 0 if X86
101	default 16
102	help
103	  Defines the size (in MiB) of the default memory area for Contiguous
104	  Memory Allocator.  If the size of 0 is selected, CMA is disabled by
105	  default, but it can be enabled by passing cma=size[MG] to the kernel.
106
107
108config CMA_SIZE_PERCENTAGE
109	int "Percentage of total memory"
110	depends on !CMA_SIZE_SEL_MBYTES
111	default 0 if X86
112	default 10
113	help
114	  Defines the size of the default memory area for Contiguous Memory
115	  Allocator as a percentage of the total memory in the system.
116	  If 0 percent is selected, CMA is disabled by default, but it can be
117	  enabled by passing cma=size[MG] to the kernel.
118
119choice
120	prompt "Selected region size"
121	default CMA_SIZE_SEL_MBYTES
122
123config CMA_SIZE_SEL_MBYTES
124	bool "Use mega bytes value only"
125
126config CMA_SIZE_SEL_PERCENTAGE
127	bool "Use percentage value only"
128
129config CMA_SIZE_SEL_MIN
130	bool "Use lower value (minimum)"
131
132config CMA_SIZE_SEL_MAX
133	bool "Use higher value (maximum)"
134
135endchoice
136
137config CMA_ALIGNMENT
138	int "Maximum PAGE_SIZE order of alignment for contiguous buffers"
139	range 4 12
140	default 8
141	help
142	  DMA mapping framework by default aligns all buffers to the smallest
143	  PAGE_SIZE order which is greater than or equal to the requested buffer
144	  size. This works well for buffers up to a few hundreds kilobytes, but
145	  for larger buffers it just a memory waste. With this parameter you can
146	  specify the maximum PAGE_SIZE order for contiguous buffers. Larger
147	  buffers will be aligned only to this specified order. The order is
148	  expressed as a power of two multiplied by the PAGE_SIZE.
149
150	  For example, if your system defaults to 4KiB pages, the order value
151	  of 8 means that the buffers will be aligned up to 1MiB only.
152
153	  If unsure, leave the default value "8".
154
155endif
156
157config DMA_API_DEBUG
158	bool "Enable debugging of DMA-API usage"
159	select NEED_DMA_MAP_STATE
160	help
161	  Enable this option to debug the use of the DMA API by device drivers.
162	  With this option you will be able to detect common bugs in device
163	  drivers like double-freeing of DMA mappings or freeing mappings that
164	  were never allocated.
165
166	  This also attempts to catch cases where a page owned by DMA is
167	  accessed by the cpu in a way that could cause data corruption.  For
168	  example, this enables cow_user_page() to check that the source page is
169	  not undergoing DMA.
170
171	  This option causes a performance degradation.  Use only if you want to
172	  debug device drivers and dma interactions.
173
174	  If unsure, say N.
175
176config DMA_API_DEBUG_SG
177	bool "Debug DMA scatter-gather usage"
178	default y
179	depends on DMA_API_DEBUG
180	help
181	  Perform extra checking that callers of dma_map_sg() have respected the
182	  appropriate segment length/boundary limits for the given device when
183	  preparing DMA scatterlists.
184
185	  This is particularly likely to have been overlooked in cases where the
186	  dma_map_sg() API is used for general bulk mapping of pages rather than
187	  preparing literal scatter-gather descriptors, where there is a risk of
188	  unexpected behaviour from DMA API implementations if the scatterlist
189	  is technically out-of-spec.
190
191	  If unsure, say N.
192