1 /* 2 * SPDX-License-Identifier: MIT 3 * 4 * Copyright © 2016 Intel Corporation 5 */ 6 7 #include "i915_scatterlist.h" 8 #include "i915_ttm_buddy_manager.h" 9 10 #include <drm/drm_buddy.h> 11 #include <drm/drm_mm.h> 12 13 #include <linux/slab.h> 14 15 bool i915_sg_trim(struct sg_table *orig_st) 16 { 17 struct sg_table new_st; 18 struct scatterlist *sg, *new_sg; 19 unsigned int i; 20 21 if (orig_st->nents == orig_st->orig_nents) 22 return false; 23 24 if (sg_alloc_table(&new_st, orig_st->nents, GFP_KERNEL | __GFP_NOWARN)) 25 return false; 26 27 new_sg = new_st.sgl; 28 for_each_sg(orig_st->sgl, sg, orig_st->nents, i) { 29 sg_set_page(new_sg, sg_page(sg), sg->length, 0); 30 sg_dma_address(new_sg) = sg_dma_address(sg); 31 sg_dma_len(new_sg) = sg_dma_len(sg); 32 33 new_sg = sg_next(new_sg); 34 } 35 GEM_BUG_ON(new_sg); /* Should walk exactly nents and hit the end */ 36 37 sg_free_table(orig_st); 38 39 *orig_st = new_st; 40 return true; 41 } 42 43 static void i915_refct_sgt_release(struct kref *ref) 44 { 45 struct i915_refct_sgt *rsgt = 46 container_of(ref, typeof(*rsgt), kref); 47 48 sg_free_table(&rsgt->table); 49 kfree(rsgt); 50 } 51 52 static const struct i915_refct_sgt_ops rsgt_ops = { 53 .release = i915_refct_sgt_release 54 }; 55 56 /** 57 * i915_refct_sgt_init - Initialize a struct i915_refct_sgt with default ops 58 * @rsgt: The struct i915_refct_sgt to initialize. 59 * size: The size of the underlying memory buffer. 60 */ 61 void i915_refct_sgt_init(struct i915_refct_sgt *rsgt, size_t size) 62 { 63 __i915_refct_sgt_init(rsgt, size, &rsgt_ops); 64 } 65 66 /** 67 * i915_rsgt_from_mm_node - Create a refcounted sg_table from a struct 68 * drm_mm_node 69 * @node: The drm_mm_node. 70 * @region_start: An offset to add to the dma addresses of the sg list. 71 * @page_alignment: Required page alignment for each sg entry. Power of two. 72 * 73 * Create a struct sg_table, initializing it from a struct drm_mm_node, 74 * taking a maximum segment length into account, splitting into segments 75 * if necessary. 76 * 77 * Return: A pointer to a kmalloced struct i915_refct_sgt on success, negative 78 * error code cast to an error pointer on failure. 79 */ 80 struct i915_refct_sgt *i915_rsgt_from_mm_node(const struct drm_mm_node *node, 81 u64 region_start, 82 u32 page_alignment) 83 { 84 const u32 max_segment = round_down(UINT_MAX, page_alignment); 85 const u32 segment_pages = max_segment >> PAGE_SHIFT; 86 u64 block_size, offset, prev_end; 87 struct i915_refct_sgt *rsgt; 88 struct sg_table *st; 89 struct scatterlist *sg; 90 91 GEM_BUG_ON(!max_segment); 92 93 rsgt = kmalloc(sizeof(*rsgt), GFP_KERNEL); 94 if (!rsgt) 95 return ERR_PTR(-ENOMEM); 96 97 i915_refct_sgt_init(rsgt, node->size << PAGE_SHIFT); 98 st = &rsgt->table; 99 if (sg_alloc_table(st, DIV_ROUND_UP_ULL(node->size, segment_pages), 100 GFP_KERNEL)) { 101 i915_refct_sgt_put(rsgt); 102 return ERR_PTR(-ENOMEM); 103 } 104 105 sg = st->sgl; 106 st->nents = 0; 107 prev_end = (resource_size_t)-1; 108 block_size = node->size << PAGE_SHIFT; 109 offset = node->start << PAGE_SHIFT; 110 111 while (block_size) { 112 u64 len; 113 114 if (offset != prev_end || sg->length >= max_segment) { 115 if (st->nents) 116 sg = __sg_next(sg); 117 118 sg_dma_address(sg) = region_start + offset; 119 GEM_BUG_ON(!IS_ALIGNED(sg_dma_address(sg), 120 page_alignment)); 121 sg_dma_len(sg) = 0; 122 sg->length = 0; 123 st->nents++; 124 } 125 126 len = min_t(u64, block_size, max_segment - sg->length); 127 sg->length += len; 128 sg_dma_len(sg) += len; 129 130 offset += len; 131 block_size -= len; 132 133 prev_end = offset; 134 } 135 136 sg_mark_end(sg); 137 i915_sg_trim(st); 138 139 return rsgt; 140 } 141 142 /** 143 * i915_rsgt_from_buddy_resource - Create a refcounted sg_table from a struct 144 * i915_buddy_block list 145 * @res: The struct i915_ttm_buddy_resource. 146 * @region_start: An offset to add to the dma addresses of the sg list. 147 * @page_alignment: Required page alignment for each sg entry. Power of two. 148 * 149 * Create a struct sg_table, initializing it from struct i915_buddy_block list, 150 * taking a maximum segment length into account, splitting into segments 151 * if necessary. 152 * 153 * Return: A pointer to a kmalloced struct i915_refct_sgts on success, negative 154 * error code cast to an error pointer on failure. 155 */ 156 struct i915_refct_sgt *i915_rsgt_from_buddy_resource(struct ttm_resource *res, 157 u64 region_start, 158 u32 page_alignment) 159 { 160 struct i915_ttm_buddy_resource *bman_res = to_ttm_buddy_resource(res); 161 const u64 size = res->size; 162 const u32 max_segment = round_down(UINT_MAX, page_alignment); 163 struct drm_buddy *mm = bman_res->mm; 164 struct list_head *blocks = &bman_res->blocks; 165 struct drm_buddy_block *block; 166 struct i915_refct_sgt *rsgt; 167 struct scatterlist *sg; 168 struct sg_table *st; 169 resource_size_t prev_end; 170 171 GEM_BUG_ON(list_empty(blocks)); 172 GEM_BUG_ON(!max_segment); 173 174 rsgt = kmalloc(sizeof(*rsgt), GFP_KERNEL); 175 if (!rsgt) 176 return ERR_PTR(-ENOMEM); 177 178 i915_refct_sgt_init(rsgt, size); 179 st = &rsgt->table; 180 if (sg_alloc_table(st, PFN_UP(res->size), GFP_KERNEL)) { 181 i915_refct_sgt_put(rsgt); 182 return ERR_PTR(-ENOMEM); 183 } 184 185 sg = st->sgl; 186 st->nents = 0; 187 prev_end = (resource_size_t)-1; 188 189 list_for_each_entry(block, blocks, link) { 190 u64 block_size, offset; 191 192 block_size = min_t(u64, size, drm_buddy_block_size(mm, block)); 193 offset = drm_buddy_block_offset(block); 194 195 while (block_size) { 196 u64 len; 197 198 if (offset != prev_end || sg->length >= max_segment) { 199 if (st->nents) 200 sg = __sg_next(sg); 201 202 sg_dma_address(sg) = region_start + offset; 203 GEM_BUG_ON(!IS_ALIGNED(sg_dma_address(sg), 204 page_alignment)); 205 sg_dma_len(sg) = 0; 206 sg->length = 0; 207 st->nents++; 208 } 209 210 len = min_t(u64, block_size, max_segment - sg->length); 211 sg->length += len; 212 sg_dma_len(sg) += len; 213 214 offset += len; 215 block_size -= len; 216 217 prev_end = offset; 218 } 219 } 220 221 sg_mark_end(sg); 222 i915_sg_trim(st); 223 224 return rsgt; 225 } 226 227 #if IS_ENABLED(CONFIG_DRM_I915_SELFTEST) 228 #include "selftests/scatterlist.c" 229 #endif 230