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