Documentation/core-api/dma-api.rst

19 To get the dma_API, you must #include <linux/dma-mapping.h>.  This
68 size and dma_handle must all be the same as those passed into
69 dma_alloc_coherent().  cpu_addr must be the virtual address returned by
79 To get this part of the dma_API, you must #include <linux/dmapool.h>
96 for use with a given device.  It must be called in a context which
102 in bytes, and must be a power of two).  If your device has no boundary
104 from this pool must not cross 4KByte boundaries.
145 dma_pool_destroy() frees the resources of the pool.  It must be
270 	Further, the DMA address of the memory must be within the
291 	correctly, the mapped region must begin exactly on a cache line
300 	DMA_TO_DEVICE synchronisation must be done after the last modification
307 	DMA_FROM_DEVICE synchronisation must be done before the driver
315 	you must always sync bidirectional memory twice: once before the
328 must be identical to those passed in (and returned) by the mapping
388 does, 0 is returned and a driver must take appropriate action. It is
421 must be the same as those and passed in to the scatter/gather mapping
424 Note: <nents> must be the number you passed in, *not* the number of
450 and device. With the sync_sg API, all the parameters must be the same
458    You must do this:
578 dev, size, dma_handle and dir must all be the same as those passed into
579 dma_alloc_pages().  page must be the pointer returned by dma_alloc_pages().
588 dev and size must be the same as those passed into dma_alloc_pages().
589 page must be the pointer returned by dma_alloc_pages().
608 dev, size, dma_handle and dir must all be the same as those passed into
609 dma_alloc_noncoherent().  cpu_addr must be the virtual address returned by
635 The attrs argument must be either 0 or DMA_ATTR_ALLOC_SINGLE_PAGES.
650 and dir must all be the same as those passed into dma_alloc_noncontiguous().
651 sgt must be the pointer returned by dma_alloc_noncontiguous().
660 dma_alloc_noncontiguous().  dev and size must be the same as those passed into
661 dma_alloc_noncontiguous().  sgt must be the pointer returned by
665 flush_kernel_vmap_range() and invalidate_kernel_vmap_range() APIs must be used
674 Unmap a kernel mapping returned by dma_vmap_noncontiguous().  dev must be the
675 same the one passed into dma_alloc_noncontiguous().  vaddr must be the pointer
686 space.  dev and size must be the same as those passed into
687 dma_alloc_noncontiguous().  sgt must be the pointer returned by
696 alignment *and* width that you must observe when either mapping
710 The DMA-API as described above has some constraints. DMA addresses must be