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dma-coherent: add documentation to new interfaces

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Signed-off-by: Dmitry Baryshkov <dbaryshkov@gmail.com>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Dmitry Baryshkov
2008-07-20 15:01:10 +04:00
committed by Ingo Molnar
parent 8fa8b9fbab
commit b6d4f7e3ef
1 changed files with 28 additions and 0 deletions
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28
kernel/dma-coherent.c
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@@ -92,6 +92,21 @@ void *dma_mark_declared_memory_occupied(struct device *dev,
} }
EXPORT_SYMBOL(dma_mark_declared_memory_occupied); EXPORT_SYMBOL(dma_mark_declared_memory_occupied);
/**
* Try to allocate memory from the per-device coherent area.
*
* @dev: device from which we allocate memory
* @size: size of requested memory area
* @dma_handle: This will be filled with the correct dma handle
* @ret: This pointer will be filled with the virtual address
* to allocated area.
*
* This function should be only called from per-arch %dma_alloc_coherent()
* to support allocation from per-device coherent memory pools.
*
* Returns 0 if dma_alloc_coherent should continue with allocating from
* generic memory areas, or !0 if dma_alloc_coherent should return %ret.
*/
int dma_alloc_from_coherent(struct device *dev, ssize_t size, int dma_alloc_from_coherent(struct device *dev, ssize_t size,
dma_addr_t *dma_handle, void **ret) dma_addr_t *dma_handle, void **ret)
{ {
@@ -111,6 +126,19 @@ int dma_alloc_from_coherent(struct device *dev, ssize_t size,
return (mem != NULL); return (mem != NULL);
} }
/**
* Try to free the memory allocated from per-device coherent memory pool.
* @dev: device from which the memory was allocated
* @order: the order of pages allocated
* @vaddr: virtual address of allocated pages
*
* This checks whether the memory was allocated from the per-device
* coherent memory pool and if so, releases that memory.
*
* Returns 1 if we correctly released the memory, or 0 if
* %dma_release_coherent() should proceed with releasing memory from
* generic pools.
*/
int dma_release_from_coherent(struct device *dev, int order, void *vaddr) int dma_release_from_coherent(struct device *dev, int order, void *vaddr)
{ {
struct dma_coherent_mem *mem = dev ? dev->dma_mem : NULL; struct dma_coherent_mem *mem = dev ? dev->dma_mem : NULL;