xref: /openbmc/linux/kernel/dma/Kconfig (revision 51bc620b)
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
23config DMA_DECLARE_COHERENT
24	bool
25
26config ARCH_HAS_SETUP_DMA_OPS
27	bool
28
29config ARCH_HAS_TEARDOWN_DMA_OPS
30	bool
31
32config ARCH_HAS_SYNC_DMA_FOR_DEVICE
33	bool
34
35config ARCH_HAS_SYNC_DMA_FOR_CPU
36	bool
37	select NEED_DMA_MAP_STATE
38
39config ARCH_HAS_SYNC_DMA_FOR_CPU_ALL
40	bool
41
42config ARCH_HAS_DMA_PREP_COHERENT
43	bool
44
45config ARCH_HAS_DMA_COHERENT_TO_PFN
46	bool
47
48config ARCH_HAS_DMA_MMAP_PGPROT
49	bool
50
51config ARCH_HAS_FORCE_DMA_UNENCRYPTED
52	bool
53
54config DMA_NONCOHERENT_CACHE_SYNC
55	bool
56
57config DMA_VIRT_OPS
58	bool
59	depends on HAS_DMA
60
61config SWIOTLB
62	bool
63	select NEED_DMA_MAP_STATE
64
65config DMA_REMAP
66	depends on MMU
67	select GENERIC_ALLOCATOR
68	bool
69
70config DMA_DIRECT_REMAP
71	bool
72	select DMA_REMAP
73
74config DMA_CMA
75	bool "DMA Contiguous Memory Allocator"
76	depends on HAVE_DMA_CONTIGUOUS && CMA
77	help
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.
81
82	  You can disable CMA by specifying "cma=0" on the kernel's command
83	  line.
84
85	  For more information see <include/linux/dma-contiguous.h>.
86	  If unsure, say "n".
87
88if  DMA_CMA
89comment "Default contiguous memory area size:"
90
91config CMA_SIZE_MBYTES
92	int "Size in Mega Bytes"
93	depends on !CMA_SIZE_SEL_PERCENTAGE
94	default 0 if X86
95	default 16
96	help
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.
100
101
102config CMA_SIZE_PERCENTAGE
103	int "Percentage of total memory"
104	depends on !CMA_SIZE_SEL_MBYTES
105	default 0 if X86
106	default 10
107	help
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.
112
113choice
114	prompt "Selected region size"
115	default CMA_SIZE_SEL_MBYTES
116
117config CMA_SIZE_SEL_MBYTES
118	bool "Use mega bytes value only"
119
120config CMA_SIZE_SEL_PERCENTAGE
121	bool "Use percentage value only"
122
123config CMA_SIZE_SEL_MIN
124	bool "Use lower value (minimum)"
125
126config CMA_SIZE_SEL_MAX
127	bool "Use higher value (maximum)"
128
129endchoice
130
131config CMA_ALIGNMENT
132	int "Maximum PAGE_SIZE order of alignment for contiguous buffers"
133	range 4 12
134	default 8
135	help
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.
143
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.
146
147	  If unsure, leave the default value "8".
148
149endif
150
151config DMA_API_DEBUG
152	bool "Enable debugging of DMA-API usage"
153	select NEED_DMA_MAP_STATE
154	help
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.
159
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
163	  not undergoing DMA.
164
165	  This option causes a performance degradation.  Use only if you want to
166	  debug device drivers and dma interactions.
167
168	  If unsure, say N.
169
170config DMA_API_DEBUG_SG
171	bool "Debug DMA scatter-gather usage"
172	default y
173	depends on DMA_API_DEBUG
174	help
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.
178
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.
184
185	  If unsure, say N.
186