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These are all kernel internal interfaces that get copied around a lot. In most cases, architectures can provide their own optimized versions, but these generic versions can work as well. I have tried to use the most common contents of each header to allow existing architectures to migrate easily. Thanks to Remis for suggesting a number of cleanups. Signed-off-by: Remis Lima Baima <remis.developer@googlemail.com> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
44 lines
1.1 KiB
C
44 lines
1.1 KiB
C
#ifndef __ASM_GENERIC_SCATTERLIST_H
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#define __ASM_GENERIC_SCATTERLIST_H
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#include <linux/types.h>
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struct scatterlist {
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#ifdef CONFIG_DEBUG_SG
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unsigned long sg_magic;
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#endif
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unsigned long page_link;
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unsigned int offset;
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unsigned int length;
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dma_addr_t dma_address;
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unsigned int dma_length;
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};
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/*
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* These macros should be used after a dma_map_sg call has been done
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* to get bus addresses of each of the SG entries and their lengths.
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* You should only work with the number of sg entries pci_map_sg
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* returns, or alternatively stop on the first sg_dma_len(sg) which
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* is 0.
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*/
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#define sg_dma_address(sg) ((sg)->dma_address)
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#ifndef sg_dma_len
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/*
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* Normally, you have an iommu on 64 bit machines, but not on 32 bit
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* machines. Architectures that are differnt should override this.
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*/
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#if __BITS_PER_LONG == 64
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#define sg_dma_len(sg) ((sg)->dma_length)
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#else
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#define sg_dma_len(sg) ((sg)->length)
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#endif /* 64 bit */
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#endif /* sg_dma_len */
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#ifndef ISA_DMA_THRESHOLD
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#define ISA_DMA_THRESHOLD (~0UL)
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#endif
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#define ARCH_HAS_SG_CHAIN
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#endif /* __ASM_GENERIC_SCATTERLIST_H */
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