DMA-API.txt: add dma_sync_single/sg API description

[mv-sheeva.git] / Documentation / DMA-API.txt

diff --git a/Documentation/DMA-API.txt b/Documentation/DMA-API.txt
index bb0e75e368b2c214aaa36814718684194cd73d0f..c8db3d0dba50f32d2ee0a4319ac94035f55255f6 100644 (file)
--- a/Documentation/DMA-API.txt
+++ b/Documentation/DMA-API.txt
@@ -364,6 +364,48 @@ API.
 Note: <nents> must be the number you passed in, *not* the number of
 physical entries returned.
 
+void
+dma_sync_single_for_cpu(struct device *dev, dma_addr_t dma_handle, size_t size,
+                       enum dma_data_direction direction)
+void
+pci_dma_sync_single_for_cpu(struct pci_dev *hwdev, dma_addr_t dma_handle,
+                           size_t size, int direction)
+void
+dma_sync_single_for_device(struct device *dev, dma_addr_t dma_handle, size_t size,
+                          enum dma_data_direction direction)
+void
+pci_dma_sync_single_for_device(struct pci_dev *hwdev, dma_addr_t dma_handle,
+                              size_t size, int direction)
+void
+dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg, int nelems,
+                   enum dma_data_direction direction)
+void
+pci_dma_sync_sg_for_cpu(struct pci_dev *hwdev, struct scatterlist *sg,
+                       int nelems, int direction)
+void
+dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg, int nelems,
+                      enum dma_data_direction direction)
+void
+pci_dma_sync_sg_for_device(struct pci_dev *hwdev, struct scatterlist *sg,
+                          int nelems, int direction)
+
+Synchronise a single contiguous or scatter/gather mapping for the cpu
+and device. With the sync_sg API, all the parameters must be the same
+as those passed into the single mapping API. With the sync_single API,
+you can use dma_handle and size parameters that aren't identical to
+those passed into the single mapping API to do a partial sync.
+
+Notes:  You must do this:
+
+- Before reading values that have been written by DMA from the device
+  (use the DMA_FROM_DEVICE direction)
+- After writing values that will be written to the device using DMA
+  (use the DMA_TO_DEVICE) direction
+- before *and* after handing memory to the device if the memory is
+  DMA_BIDIRECTIONAL
+
+See also dma_map_single().
+
 dma_addr_t
 dma_map_single_attrs(struct device *dev, void *cpu_addr, size_t size,
                     enum dma_data_direction dir,