1/* $NetBSD: i915_scatterlist.h,v 1.8 2021/12/19 11:37:05 riastradh Exp $ */ 2 3/* 4 * SPDX-License-Identifier: MIT 5 * 6 * Copyright �� 2016 Intel Corporation 7 */ 8 9#ifndef I915_SCATTERLIST_H 10#define I915_SCATTERLIST_H 11 12#include <linux/pfn.h> 13#include <linux/scatterlist.h> 14#include <linux/swiotlb.h> 15 16#include "i915_gem.h" 17 18#ifdef __NetBSD__ 19 20struct sgt_iter { 21 unsigned i; 22}; 23 24#define for_each_sgt_page(pp, iter, sgt) \ 25 for ((iter).i = 0; \ 26 ((iter).i < (sgt)->sgl->sg_npgs \ 27 ? (((pp) = (sgt)->sgl->sg_pgs[(iter).i]), 1) \ 28 : 0); \ 29 (iter).i++) 30 31static inline unsigned 32i915_sg_page_sizes(struct scatterlist *sg) 33{ 34 unsigned i, page_sizes = 0; 35 36 for (i = 0; i < sg->sg_dmamap->dm_nsegs; i++) 37 page_sizes |= sg->sg_dmamap->dm_segs[i].ds_len; 38 39 return page_sizes; 40} 41 42static inline unsigned 43i915_sg_segment_size(void) 44{ 45 return PAGE_SIZE; 46} 47 48#else 49 50/* 51 * Optimised SGL iterator for GEM objects 52 */ 53static __always_inline struct sgt_iter { 54 struct scatterlist *sgp; 55 union { 56 unsigned long pfn; 57 dma_addr_t dma; 58 }; 59 unsigned int curr; 60 unsigned int max; 61} __sgt_iter(struct scatterlist *sgl, bool dma) { 62 struct sgt_iter s = { .sgp = sgl }; 63 64 if (s.sgp) { 65 s.max = s.curr = s.sgp->offset; 66 s.max += s.sgp->length; 67 if (dma) 68 s.dma = sg_dma_address(s.sgp); 69 else 70 s.pfn = page_to_pfn(sg_page(s.sgp)); 71 } 72 73 return s; 74} 75 76static inline int __sg_page_count(const struct scatterlist *sg) 77{ 78 return sg->length >> PAGE_SHIFT; 79} 80 81static inline struct scatterlist *____sg_next(struct scatterlist *sg) 82{ 83 ++sg; 84 if (unlikely(sg_is_chain(sg))) 85 sg = sg_chain_ptr(sg); 86 return sg; 87} 88 89/** 90 * __sg_next - return the next scatterlist entry in a list 91 * @sg: The current sg entry 92 * 93 * Description: 94 * If the entry is the last, return NULL; otherwise, step to the next 95 * element in the array (@sg@+1). If that's a chain pointer, follow it; 96 * otherwise just return the pointer to the current element. 97 **/ 98static inline struct scatterlist *__sg_next(struct scatterlist *sg) 99{ 100 return sg_is_last(sg) ? NULL : ____sg_next(sg); 101} 102 103/** 104 * __for_each_sgt_daddr - iterate over the device addresses of the given sg_table 105 * @__dp: Device address (output) 106 * @__iter: 'struct sgt_iter' (iterator state, internal) 107 * @__sgt: sg_table to iterate over (input) 108 * @__step: step size 109 */ 110#define __for_each_sgt_daddr(__dp, __iter, __sgt, __step) \ 111 for ((__iter) = __sgt_iter((__sgt)->sgl, true); \ 112 ((__dp) = (__iter).dma + (__iter).curr), (__iter).sgp; \ 113 (((__iter).curr += (__step)) >= (__iter).max) ? \ 114 (__iter) = __sgt_iter(__sg_next((__iter).sgp), true), 0 : 0) 115 116/** 117 * for_each_sgt_page - iterate over the pages of the given sg_table 118 * @__pp: page pointer (output) 119 * @__iter: 'struct sgt_iter' (iterator state, internal) 120 * @__sgt: sg_table to iterate over (input) 121 */ 122#define for_each_sgt_page(__pp, __iter, __sgt) \ 123 for ((__iter) = __sgt_iter((__sgt)->sgl, false); \ 124 ((__pp) = (__iter).pfn == 0 ? NULL : \ 125 pfn_to_page((__iter).pfn + ((__iter).curr >> PAGE_SHIFT))); \ 126 (((__iter).curr += PAGE_SIZE) >= (__iter).max) ? \ 127 (__iter) = __sgt_iter(__sg_next((__iter).sgp), false), 0 : 0) 128 129static inline unsigned int i915_sg_page_sizes(struct scatterlist *sg) 130{ 131 unsigned int page_sizes; 132 133 page_sizes = 0; 134 while (sg) { 135 GEM_BUG_ON(sg->offset); 136 GEM_BUG_ON(!IS_ALIGNED(sg->length, PAGE_SIZE)); 137 page_sizes |= sg->length; 138 sg = __sg_next(sg); 139 } 140 141 return page_sizes; 142} 143 144static inline unsigned int i915_sg_segment_size(void) 145{ 146 unsigned int size = swiotlb_max_segment(); 147 148 if (size == 0) 149 return SCATTERLIST_MAX_SEGMENT; 150 151 size = rounddown(size, PAGE_SIZE); 152 /* swiotlb_max_segment_size can return 1 byte when it means one page. */ 153 if (size < PAGE_SIZE) 154 size = PAGE_SIZE; 155 156 return size; 157} 158 159#endif 160 161bool i915_sg_trim(struct sg_table *orig_st); 162 163#endif 164