scatterlist.h revision 270710
1219820Sjeff/*- 2219820Sjeff * Copyright (c) 2010 Isilon Systems, Inc. 3219820Sjeff * Copyright (c) 2010 iX Systems, Inc. 4219820Sjeff * Copyright (c) 2010 Panasas, Inc. 5270710Shselasky * Copyright (c) 2013, 2014 Mellanox Technologies, Ltd. 6219820Sjeff * All rights reserved. 7219820Sjeff * 8219820Sjeff * Redistribution and use in source and binary forms, with or without 9219820Sjeff * modification, are permitted provided that the following conditions 10219820Sjeff * are met: 11219820Sjeff * 1. Redistributions of source code must retain the above copyright 12219820Sjeff * notice unmodified, this list of conditions, and the following 13219820Sjeff * disclaimer. 14219820Sjeff * 2. Redistributions in binary form must reproduce the above copyright 15219820Sjeff * notice, this list of conditions and the following disclaimer in the 16219820Sjeff * documentation and/or other materials provided with the distribution. 17219820Sjeff * 18219820Sjeff * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 19219820Sjeff * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 20219820Sjeff * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 21219820Sjeff * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 22219820Sjeff * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 23219820Sjeff * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 24219820Sjeff * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 25219820Sjeff * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 26219820Sjeff * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 27219820Sjeff * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 28219820Sjeff */ 29270710Shselasky 30219820Sjeff#ifndef _LINUX_SCATTERLIST_H_ 31219820Sjeff#define _LINUX_SCATTERLIST_H_ 32219820Sjeff 33219820Sjeff#include <linux/page.h> 34219820Sjeff 35219820Sjeffstruct scatterlist { 36219820Sjeff union { 37219820Sjeff struct page *page; 38219820Sjeff struct scatterlist *sg; 39219820Sjeff } sl_un; 40219846Skib dma_addr_t address; 41219820Sjeff unsigned long offset; 42219820Sjeff uint32_t length; 43219820Sjeff uint32_t flags; 44219820Sjeff}; 45219820Sjeff 46270710Shselaskystruct sg_table { 47270710Shselasky struct scatterlist *sgl; /* the list */ 48270710Shselasky unsigned int nents; /* number of mapped entries */ 49270710Shselasky unsigned int orig_nents; /* original size of list */ 50270710Shselasky}; 51270710Shselasky 52219820Sjeff#define sg_dma_address(sg) (sg)->address 53219820Sjeff#define sg_dma_len(sg) (sg)->length 54219820Sjeff#define sg_page(sg) (sg)->sl_un.page 55219820Sjeff#define sg_scatternext(sg) (sg)->sl_un.sg 56219820Sjeff 57219820Sjeff#define SG_END 0x01 58219820Sjeff#define SG_CHAIN 0x02 59219820Sjeff 60219820Sjeffstatic inline void 61219820Sjeffsg_set_page(struct scatterlist *sg, struct page *page, unsigned int len, 62219820Sjeff unsigned int offset) 63219820Sjeff{ 64219820Sjeff sg_page(sg) = page; 65219820Sjeff sg_dma_len(sg) = len; 66219820Sjeff sg->offset = offset; 67219820Sjeff if (offset > PAGE_SIZE) 68219820Sjeff panic("sg_set_page: Invalid offset %d\n", offset); 69219820Sjeff} 70219820Sjeff 71219820Sjeffstatic inline void 72219820Sjeffsg_set_buf(struct scatterlist *sg, const void *buf, unsigned int buflen) 73219820Sjeff{ 74219820Sjeff sg_set_page(sg, virt_to_page(buf), buflen, 75219820Sjeff ((uintptr_t)buf) & ~PAGE_MASK); 76219820Sjeff} 77219820Sjeff 78219820Sjeffstatic inline void 79219820Sjeffsg_init_table(struct scatterlist *sg, unsigned int nents) 80219820Sjeff{ 81219820Sjeff bzero(sg, sizeof(*sg) * nents); 82219820Sjeff sg[nents - 1].flags = SG_END; 83219820Sjeff} 84219820Sjeff 85219820Sjeffstatic inline struct scatterlist * 86219820Sjeffsg_next(struct scatterlist *sg) 87219820Sjeff{ 88219820Sjeff if (sg->flags & SG_END) 89219820Sjeff return (NULL); 90219820Sjeff sg++; 91219820Sjeff if (sg->flags & SG_CHAIN) 92219820Sjeff sg = sg_scatternext(sg); 93219820Sjeff return (sg); 94219820Sjeff} 95219820Sjeff 96219820Sjeffstatic inline vm_paddr_t 97219820Sjeffsg_phys(struct scatterlist *sg) 98219820Sjeff{ 99219820Sjeff return sg_page(sg)->phys_addr + sg->offset; 100219820Sjeff} 101219820Sjeff 102219820Sjeff#define for_each_sg(sglist, sg, sgmax, _itr) \ 103219820Sjeff for (_itr = 0, sg = (sglist); _itr < (sgmax); _itr++, sg = sg_next(sg)) 104219820Sjeff 105219820Sjeff#endif /* _LINUX_SCATTERLIST_H_ */ 106