141 lines
3.5 KiB
C
141 lines
3.5 KiB
C
/* $OpenBSD: scatterlist.h,v 1.7 2024/01/06 09:33:08 kettenis Exp $ */
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/*
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* Copyright (c) 2013, 2014, 2015 Mark Kettenis
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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#ifndef _LINUX_SCATTERLIST_H
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#define _LINUX_SCATTERLIST_H
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#include <sys/types.h>
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#include <sys/param.h>
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#include <uvm/uvm_extern.h>
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#include <linux/mm.h>
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#include <linux/fwnode.h> /* via asm/io.h -> logic_pio.h */
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struct scatterlist {
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struct vm_page *__page;
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dma_addr_t dma_address;
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unsigned int offset;
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unsigned int length;
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bool end;
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};
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struct sg_table {
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struct scatterlist *sgl;
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unsigned int nents;
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unsigned int orig_nents;
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bus_dmamap_t dmamap;
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};
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struct sg_page_iter {
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struct scatterlist *sg;
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unsigned int sg_pgoffset;
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unsigned int __nents;
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};
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#define sg_is_chain(sg) false
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#define sg_is_last(sg) ((sg)->end)
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#define sg_chain_ptr(sg) NULL
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static inline struct scatterlist *
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sg_next(struct scatterlist *sgl)
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{
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return sg_is_last(sgl) ? NULL : ++sgl;
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}
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int sg_alloc_table(struct sg_table *, unsigned int, gfp_t);
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void sg_free_table(struct sg_table *);
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static inline void
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sg_mark_end(struct scatterlist *sgl)
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{
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sgl->end = true;
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}
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static inline void
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__sg_page_iter_start(struct sg_page_iter *iter, struct scatterlist *sgl,
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unsigned int nents, unsigned long pgoffset)
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{
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iter->sg = sgl;
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iter->sg_pgoffset = pgoffset - 1;
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iter->__nents = nents;
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}
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static inline bool
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__sg_page_iter_next(struct sg_page_iter *iter)
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{
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iter->sg_pgoffset++;
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while (iter->__nents > 0 &&
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iter->sg_pgoffset >= (iter->sg->length / PAGE_SIZE)) {
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iter->sg_pgoffset -= (iter->sg->length / PAGE_SIZE);
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iter->sg++;
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iter->__nents--;
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}
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return (iter->__nents > 0);
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}
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static inline paddr_t
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sg_page_iter_dma_address(struct sg_page_iter *iter)
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{
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return iter->sg->dma_address + (iter->sg_pgoffset << PAGE_SHIFT);
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}
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static inline struct vm_page *
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sg_page_iter_page(struct sg_page_iter *iter)
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{
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return PHYS_TO_VM_PAGE(sg_page_iter_dma_address(iter));
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}
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static inline struct vm_page *
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sg_page(struct scatterlist *sgl)
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{
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return sgl->__page;
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}
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static inline void
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sg_assign_page(struct scatterlist *sgl, struct vm_page *page)
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{
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sgl->__page = page;
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}
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static inline void
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sg_set_page(struct scatterlist *sgl, struct vm_page *page,
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unsigned int length, unsigned int offset)
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{
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sgl->__page = page;
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sgl->dma_address = page ? VM_PAGE_TO_PHYS(page) : 0;
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sgl->offset = offset;
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sgl->length = length;
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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 for_each_sg(sgl, sg, nents, i) \
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for (i = 0, sg = (sgl); i < (nents); i++, sg = sg_next(sg))
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#define for_each_sg_page(sgl, iter, nents, pgoffset) \
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__sg_page_iter_start((iter), (sgl), (nents), (pgoffset)); \
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while (__sg_page_iter_next(iter))
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#define for_each_sgtable_page(st, iter, pgoffset) \
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for_each_sg_page((st)->sgl, iter, (st)->orig_nents, pgoffset)
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size_t sg_copy_from_buffer(struct scatterlist *, unsigned int,
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const void *, size_t);
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#endif
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