Documentation/core-api/dma-attributes.rst

6 defined in linux/dma-mapping.h.
9 ----------------------
19 ----------------------
29 --------------------------
33 such mapping is non-trivial task and consumes very limited resources
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49 By default dma_map_{single,page,sg} functions family transfer a given
50 buffer from CPU domain to device domain. Some advanced use cases might
53 performed by calling dma_map_{single,page,sg} function more than once
55 the buffer sharing. The first call transfers a buffer from 'CPU' domain
56 to 'device' domain, what synchronizes CPU caches for the given region
59 dma_map_{single,page,sg}() for other devices will perform exactly the
60 same synchronization operation on the CPU cache. CPU cache synchronization
64 the CPU cache for the given buffer assuming that it has been already
66 dma_unmap_{single,page,sg} functions family to force buffer to stay in
71 -------------------------
73 By default DMA-mapping subsystem is allowed to assemble the buffer
80 ---------------------------
82 This is a hint to the DMA-mapping subsystem that it's probably not worth
87 - You know that the accesses to this memory won't thrash the TLB.
89   that they aren't sequential but it's unlikely you'll ping-pong
92 - You know that the penalty of TLB misses while accessing the
96 - You know that the DMA mapping is fairly transitory.  If you expect
108 ----------------
110 This tells the DMA-mapping subsystem to suppress allocation failure reports
125 -------------------
129 "user" modes.  This attribute is used to indicate to the DMA-mapping
131 level (and ideally inaccessible or at least read-only at the
132 lesser-privileged levels).