Diffstat (limited to 'Documentation')
1 files changed, 17 insertions, 38 deletions
diff --git a/Documentation/DMA-API.txt b/Documentation/DMA-API.txt
index 45b29326d719..ac66ae2509a9 100644
@@ -515,14 +515,15 @@ API at all.
- dma_alloc_noncoherent(struct device *dev, size_t size,
- dma_addr_t *dma_handle, gfp_t flag)
+ dma_alloc_attrs(struct device *dev, size_t size, dma_addr_t *dma_handle,
+ gfp_t flag, unsigned long attrs)
-Identical to dma_alloc_coherent() except that the platform will
-choose to return either consistent or non-consistent memory as it sees
-fit. By using this API, you are guaranteeing to the platform that you
-have all the correct and necessary sync points for this memory in the
-driver should it choose to return non-consistent memory.
+Identical to dma_alloc_coherent() except that when the
+DMA_ATTR_NON_CONSISTENT flags is passed in the attrs argument, the
+platform will choose to return either consistent or non-consistent memory
+as it sees fit. By using this API, you are guaranteeing to the platform
+that you have all the correct and necessary sync points for this memory
+in the driver should it choose to return non-consistent memory.
Note: where the platform can return consistent memory, it will
guarantee that the sync points become nops.
@@ -535,12 +536,13 @@ that simply cannot make consistent memory.
- dma_free_noncoherent(struct device *dev, size_t size, void *cpu_addr,
- dma_addr_t dma_handle)
+ dma_free_attrs(struct device *dev, size_t size, void *cpu_addr,
+ dma_addr_t dma_handle, unsigned long attrs)
-Free memory allocated by the nonconsistent API. All parameters must
-be identical to those passed in (and returned by
+Free memory allocated by the dma_alloc_attrs(). All parameters common
+parameters must identical to those otherwise passed to dma_fre_coherent,
+and the attrs argument must be identical to the attrs passed to
@@ -564,8 +566,8 @@ memory or doing partial flushes.
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
-dma_alloc_noncoherent(), starting at virtual address vaddr and
+Do a partial sync of memory that was allocated by dma_alloc_attrs() with
+the DMA_ATTR_NON_CONSISTENT flag starting at virtual address vaddr and
continuing on for size. Again, you *must* observe the cache line
boundaries when doing this.
@@ -590,34 +592,11 @@ size is the size of the area (must be multiples of PAGE_SIZE).
flags can be ORed together and are:
-- DMA_MEMORY_MAP - request that the memory returned from
- 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.
-One or both of these flags must be present.
-- DMA_MEMORY_INCLUDES_CHILDREN - make the declared memory be allocated by
- dma_alloc_coherent of any child devices of this one (for memory residing
- on a bridge).
- DMA_MEMORY_EXCLUSIVE - only allocate memory from the declared regions.
Do not allow dma_alloc_coherent() to fall back to system memory when
it's out of memory in the declared region.
-The return value will be either DMA_MEMORY_MAP or DMA_MEMORY_IO and
-must correspond to a passed in flag (i.e. no returning DMA_MEMORY_IO
-if only DMA_MEMORY_MAP were passed in) for success or zero for
-Note, for DMA_MEMORY_IO returns, all subsequent memory returned by
-dma_alloc_coherent() may no longer be accessed directly, but instead
-must be accessed using the correct bus functions. If your driver
-isn't prepared to handle this contingency, it should not specify
-DMA_MEMORY_IO in the input flags.
-As a simplification for the platforms, only **one** such region of
+As a simplification for the platforms, only *one* such region of
memory may be declared per device.
For reasons of efficiency, most platforms choose to track the declared