1 2config HAS_DMA 3 bool 4 depends on !NO_DMA 5 default y 6 7config NEED_SG_DMA_LENGTH 8 bool 9 10config NEED_DMA_MAP_STATE 11 bool 12 13config ARCH_DMA_ADDR_T_64BIT 14 def_bool 64BIT || PHYS_ADDR_T_64BIT 15 16config ARCH_HAS_DMA_COHERENCE_H 17 bool 18 19config ARCH_HAS_DMA_SET_MASK 20 bool 21 22config DMA_DECLARE_COHERENT 23 bool 24 25config ARCH_HAS_SETUP_DMA_OPS 26 bool 27 28config ARCH_HAS_TEARDOWN_DMA_OPS 29 bool 30 31config ARCH_HAS_SYNC_DMA_FOR_DEVICE 32 bool 33 34config ARCH_HAS_SYNC_DMA_FOR_CPU 35 bool 36 select NEED_DMA_MAP_STATE 37 38config ARCH_HAS_SYNC_DMA_FOR_CPU_ALL 39 bool 40 41config ARCH_HAS_DMA_PREP_COHERENT 42 bool 43 44config ARCH_HAS_DMA_COHERENT_TO_PFN 45 bool 46 47config ARCH_HAS_DMA_MMAP_PGPROT 48 bool 49 50config DMA_NONCOHERENT_CACHE_SYNC 51 bool 52 53config DMA_VIRT_OPS 54 bool 55 depends on HAS_DMA 56 57config SWIOTLB 58 bool 59 select NEED_DMA_MAP_STATE 60 61config DMA_REMAP 62 depends on MMU 63 select GENERIC_ALLOCATOR 64 bool 65 66config DMA_DIRECT_REMAP 67 bool 68 select DMA_REMAP 69 70config DMA_CMA 71 bool "DMA Contiguous Memory Allocator" 72 depends on HAVE_DMA_CONTIGUOUS && CMA 73 help 74 This enables the Contiguous Memory Allocator which allows drivers 75 to allocate big physically-contiguous blocks of memory for use with 76 hardware components that do not support I/O map nor scatter-gather. 77 78 You can disable CMA by specifying "cma=0" on the kernel's command 79 line. 80 81 For more information see <include/linux/dma-contiguous.h>. 82 If unsure, say "n". 83 84if DMA_CMA 85comment "Default contiguous memory area size:" 86 87config CMA_SIZE_MBYTES 88 int "Size in Mega Bytes" 89 depends on !CMA_SIZE_SEL_PERCENTAGE 90 default 0 if X86 91 default 16 92 help 93 Defines the size (in MiB) of the default memory area for Contiguous 94 Memory Allocator. If the size of 0 is selected, CMA is disabled by 95 default, but it can be enabled by passing cma=size[MG] to the kernel. 96 97 98config CMA_SIZE_PERCENTAGE 99 int "Percentage of total memory" 100 depends on !CMA_SIZE_SEL_MBYTES 101 default 0 if X86 102 default 10 103 help 104 Defines the size of the default memory area for Contiguous Memory 105 Allocator as a percentage of the total memory in the system. 106 If 0 percent is selected, CMA is disabled by default, but it can be 107 enabled by passing cma=size[MG] to the kernel. 108 109choice 110 prompt "Selected region size" 111 default CMA_SIZE_SEL_MBYTES 112 113config CMA_SIZE_SEL_MBYTES 114 bool "Use mega bytes value only" 115 116config CMA_SIZE_SEL_PERCENTAGE 117 bool "Use percentage value only" 118 119config CMA_SIZE_SEL_MIN 120 bool "Use lower value (minimum)" 121 122config CMA_SIZE_SEL_MAX 123 bool "Use higher value (maximum)" 124 125endchoice 126 127config CMA_ALIGNMENT 128 int "Maximum PAGE_SIZE order of alignment for contiguous buffers" 129 range 4 12 130 default 8 131 help 132 DMA mapping framework by default aligns all buffers to the smallest 133 PAGE_SIZE order which is greater than or equal to the requested buffer 134 size. This works well for buffers up to a few hundreds kilobytes, but 135 for larger buffers it just a memory waste. With this parameter you can 136 specify the maximum PAGE_SIZE order for contiguous buffers. Larger 137 buffers will be aligned only to this specified order. The order is 138 expressed as a power of two multiplied by the PAGE_SIZE. 139 140 For example, if your system defaults to 4KiB pages, the order value 141 of 8 means that the buffers will be aligned up to 1MiB only. 142 143 If unsure, leave the default value "8". 144 145endif 146 147config DMA_API_DEBUG 148 bool "Enable debugging of DMA-API usage" 149 select NEED_DMA_MAP_STATE 150 help 151 Enable this option to debug the use of the DMA API by device drivers. 152 With this option you will be able to detect common bugs in device 153 drivers like double-freeing of DMA mappings or freeing mappings that 154 were never allocated. 155 156 This also attempts to catch cases where a page owned by DMA is 157 accessed by the cpu in a way that could cause data corruption. For 158 example, this enables cow_user_page() to check that the source page is 159 not undergoing DMA. 160 161 This option causes a performance degradation. Use only if you want to 162 debug device drivers and dma interactions. 163 164 If unsure, say N. 165 166config DMA_API_DEBUG_SG 167 bool "Debug DMA scatter-gather usage" 168 default y 169 depends on DMA_API_DEBUG 170 help 171 Perform extra checking that callers of dma_map_sg() have respected the 172 appropriate segment length/boundary limits for the given device when 173 preparing DMA scatterlists. 174 175 This is particularly likely to have been overlooked in cases where the 176 dma_map_sg() API is used for general bulk mapping of pages rather than 177 preparing literal scatter-gather descriptors, where there is a risk of 178 unexpected behaviour from DMA API implementations if the scatterlist 179 is technically out-of-spec. 180 181 If unsure, say N. 182