X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=Documentation%2FDMA-API.txt;h=1af0f2d5022066f1a205ad5265771e3ab112c018;hb=987b0145d94eecf292d8b301228356f44611ab7c;hp=2ffb0d62f0fe3ed8156586505b7faf1efe1c33ce;hpb=f7ed79d23a47594e7834d66a8f14449796d4f3e6;p=linux-2.6.git

diff --git a/Documentation/DMA-API.txt b/Documentation/DMA-API.txt
index 2ffb0d62f..1af0f2d50 100644
--- a/Documentation/DMA-API.txt
+++ b/Documentation/DMA-API.txt
@@ -33,9 +33,7 @@ pci_alloc_consistent(struct pci_dev *dev, size_t size,
 
 Consistent memory is memory for which a write by either the device or
 the processor can immediately be read by the processor or device
-without having to worry about caching effects.  (You may however need
-to make sure to flush the processor's write buffers before telling
-devices to read that memory.)
+without having to worry about caching effects.
 
 This routine allocates a region of <size> bytes of consistent memory.
 it also returns a <dma_handle> which may be cast to an unsigned
@@ -306,12 +304,12 @@ dma address with dma_mapping_error(). A non zero return value means the mapping
 could not be created and the driver should take appropriate action (eg
 reduce current DMA mapping usage or delay and try again later).
 
-	int
-	dma_map_sg(struct device *dev, struct scatterlist *sg,
-		int nents, enum dma_data_direction direction)
-	int
-	pci_map_sg(struct pci_dev *hwdev, struct scatterlist *sg,
-		int nents, int direction)
+int
+dma_map_sg(struct device *dev, struct scatterlist *sg, int nents,
+	   enum dma_data_direction direction)
+int
+pci_map_sg(struct pci_dev *hwdev, struct scatterlist *sg,
+	   int nents, int direction)
 
 Maps a scatter gather list from the block layer.
 
@@ -329,33 +327,12 @@ critical that the driver do something, in the case of a block driver
 aborting the request or even oopsing is better than doing nothing and
 corrupting the filesystem.
 
-With scatterlists, you use the resulting mapping like this:
-
-	int i, count = dma_map_sg(dev, sglist, nents, direction);
-	struct scatterlist *sg;
-
-	for (i = 0, sg = sglist; i < count; i++, sg++) {
-		hw_address[i] = sg_dma_address(sg);
-		hw_len[i] = sg_dma_len(sg);
-	}
-
-where nents is the number of entries in the sglist.
-
-The implementation is free to merge several consecutive sglist entries
-into one (e.g. with an IOMMU, or if several pages just happen to be
-physically contiguous) and returns the actual number of sg entries it
-mapped them to. On failure 0, is returned.
-
-Then you should loop count times (note: this can be less than nents times)
-and use sg_dma_address() and sg_dma_len() macros where you previously
-accessed sg->address and sg->length as shown above.
-
-	void
-	dma_unmap_sg(struct device *dev, struct scatterlist *sg,
-		int nhwentries, enum dma_data_direction direction)
-	void
-	pci_unmap_sg(struct pci_dev *hwdev, struct scatterlist *sg,
-		int nents, int direction)
+void
+dma_unmap_sg(struct device *dev, struct scatterlist *sg, int nhwentries,
+	     enum dma_data_direction direction)
+void
+pci_unmap_sg(struct pci_dev *hwdev, struct scatterlist *sg,
+	     int nents, int direction)
 
 unmap the previously mapped scatter/gather list.  All the parameters
 must be the same as those and passed in to the scatter/gather mapping