diff options
Diffstat (limited to 'Documentation/DMA-API.txt')
| -rw-r--r-- | Documentation/DMA-API.txt | 14 |
1 files changed, 7 insertions, 7 deletions
diff --git a/Documentation/DMA-API.txt b/Documentation/DMA-API.txt index 2ffb0d62f0fe..805db4b2cba6 100644 --- a/Documentation/DMA-API.txt +++ b/Documentation/DMA-API.txt @@ -77,7 +77,7 @@ To get this part of the dma_ API, you must #include <linux/dmapool.h> Many drivers need lots of small dma-coherent memory regions for DMA descriptors or I/O buffers. Rather than allocating in units of a page or more using dma_alloc_coherent(), you can use DMA pools. These work -much like a kmem_cache_t, except that they use the dma-coherent allocator +much like a struct kmem_cache, except that they use the dma-coherent allocator not __get_free_pages(). Also, they understand common hardware constraints for alignment, like queue heads needing to be aligned on N byte boundaries. @@ -94,7 +94,7 @@ The pool create() routines initialize a pool of dma-coherent buffers for use with a given device. It must be called in a context which can sleep. -The "name" is for diagnostics (like a kmem_cache_t name); dev and size +The "name" is for diagnostics (like a struct kmem_cache name); dev and size are like what you'd pass to dma_alloc_coherent(). The device's hardware alignment requirement for this type of data is "align" (which is expressed in bytes, and must be a power of two). If your device has no boundary @@ -431,10 +431,10 @@ be identical to those passed in (and returned by dma_alloc_noncoherent()). int -dma_is_consistent(dma_addr_t dma_handle) +dma_is_consistent(struct device *dev, dma_addr_t dma_handle) -returns true if the memory pointed to by the dma_handle is actually -consistent. +returns true if the device dev is performing consistent DMA on the memory +area pointed to by the dma_handle. int dma_get_cache_alignment(void) @@ -459,7 +459,7 @@ anything like this. You must also be extra careful about accessing memory you intend to sync partially. void -dma_cache_sync(void *vaddr, size_t size, +dma_cache_sync(struct device *dev, void *vaddr, size_t size, enum dma_data_direction direction) Do a partial sync of memory that was allocated by @@ -489,7 +489,7 @@ size is the size of the area (must be multiples of PAGE_SIZE). flags can be or'd together and are DMA_MEMORY_MAP - request that the memory returned from -dma_alloc_coherent() be directly writeable. +dma_alloc_coherent() be directly writable. DMA_MEMORY_IO - request that the memory returned from dma_alloc_coherent() be addressable using read/write/memcpy_toio etc. |