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