mirror of https://gitee.com/openkylin/linux.git
47 lines
1.3 KiB
C
47 lines
1.3 KiB
C
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#ifndef _ASM_SCATTERLIST_H
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#define _ASM_SCATTERLIST_H
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#include <asm/types.h>
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/*
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* Drivers must set either ->address or (preferred) page and ->offset
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* to indicate where data must be transferred to/from.
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*
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* Using page is recommended since it handles highmem data as well as
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* low mem. ->address is restricted to data which has a virtual mapping, and
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* it will go away in the future. Updating to page can be automated very
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* easily -- something like
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*
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* sg->address = some_ptr;
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*
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* can be rewritten as
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*
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* sg_set_buf(sg, some_ptr, length);
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*
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* and that's it. There's no excuse for not highmem enabling YOUR driver. /jens
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*/
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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; /* for highmem, page offset */
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dma_addr_t dma_address;
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unsigned int length;
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};
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/*
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* These macros should be used after a pci_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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#define sg_dma_len(sg) ((sg)->length)
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#define ISA_DMA_THRESHOLD (0xffffffffUL)
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#endif /* !_ASM_SCATTERLIST_H */
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