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authorDmitry Baryshkov <dbaryshkov@gmail.com>2008-07-20 15:01:10 +0400
committerIngo Molnar <mingo@elte.hu>2008-07-20 21:22:00 +0200
commitb6d4f7e3ef25beb8c658c97867d98883e69dc544 (patch)
treeb89a6c5588cae046ab9e007e22354ebdacb9318a /kernel
parent8fa8b9fbab90c74139e8e868fe5b30b6a9f6be65 (diff)
downloadop-kernel-dev-b6d4f7e3ef25beb8c658c97867d98883e69dc544.zip
op-kernel-dev-b6d4f7e3ef25beb8c658c97867d98883e69dc544.tar.gz
dma-coherent: add documentation to new interfaces
Signed-off-by: Dmitry Baryshkov <dbaryshkov@gmail.com> Cc: Jesse Barnes <jbarnes@virtuousgeek.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/dma-coherent.c28
1 files changed, 28 insertions, 0 deletions
diff --git a/kernel/dma-coherent.c b/kernel/dma-coherent.c
index 56dff5c..7517115 100644
--- a/kernel/dma-coherent.c
+++ b/kernel/dma-coherent.c
@@ -92,6 +92,21 @@ void *dma_mark_declared_memory_occupied(struct device *dev,
}
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,
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);
}
+/**
+ * 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)
{
struct dma_coherent_mem *mem = dev ? dev->dma_mem : NULL;
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