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