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