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 /* restricted by sg_alloc_table */ 100 if (WARN_ON(overflows_type(DIV_ROUND_UP_ULL(node->size, segment_pages), 101 unsigned int))) 102 return ERR_PTR(-E2BIG); 103 104 if (sg_alloc_table(st, DIV_ROUND_UP_ULL(node->size, segment_pages), 105 GFP_KERNEL)) { 106 i915_refct_sgt_put(rsgt); 107 return ERR_PTR(-ENOMEM); 108 } 109 110 sg = st->sgl; 111 st->nents = 0; 112 prev_end = (resource_size_t)-1; 113 block_size = node->size << PAGE_SHIFT; 114 offset = node->start << PAGE_SHIFT; 115 116 while (block_size) { 117 u64 len; 118 119 if (offset != prev_end || sg->length >= max_segment) { 120 if (st->nents) 121 sg = __sg_next(sg); 122 123 sg_dma_address(sg) = region_start + offset; 124 GEM_BUG_ON(!IS_ALIGNED(sg_dma_address(sg), 125 page_alignment)); 126 sg_dma_len(sg) = 0; 127 sg->length = 0; 128 st->nents++; 129 } 130 131 len = min_t(u64, block_size, max_segment - sg->length); 132 sg->length += len; 133 sg_dma_len(sg) += len; 134 135 offset += len; 136 block_size -= len; 137 138 prev_end = offset; 139 } 140 141 sg_mark_end(sg); 142 i915_sg_trim(st); 143 144 return rsgt; 145 } 146 147 /** 148 * i915_rsgt_from_buddy_resource - Create a refcounted sg_table from a struct 149 * i915_buddy_block list 150 * @res: The struct i915_ttm_buddy_resource. 151 * @region_start: An offset to add to the dma addresses of the sg list. 152 * @page_alignment: Required page alignment for each sg entry. Power of two. 153 * 154 * Create a struct sg_table, initializing it from struct i915_buddy_block list, 155 * taking a maximum segment length into account, splitting into segments 156 * if necessary. 157 * 158 * Return: A pointer to a kmalloced struct i915_refct_sgts on success, negative 159 * error code cast to an error pointer on failure. 160 */ 161 struct i915_refct_sgt *i915_rsgt_from_buddy_resource(struct ttm_resource *res, 162 u64 region_start, 163 u32 page_alignment) 164 { 165 struct i915_ttm_buddy_resource *bman_res = to_ttm_buddy_resource(res); 166 const u64 size = res->size; 167 const u32 max_segment = round_down(UINT_MAX, page_alignment); 168 struct drm_buddy *mm = bman_res->mm; 169 struct list_head *blocks = &bman_res->blocks; 170 struct drm_buddy_block *block; 171 struct i915_refct_sgt *rsgt; 172 struct scatterlist *sg; 173 struct sg_table *st; 174 resource_size_t prev_end; 175 176 GEM_BUG_ON(list_empty(blocks)); 177 GEM_BUG_ON(!max_segment); 178 179 rsgt = kmalloc(sizeof(*rsgt), GFP_KERNEL); 180 if (!rsgt) 181 return ERR_PTR(-ENOMEM); 182 183 i915_refct_sgt_init(rsgt, size); 184 st = &rsgt->table; 185 /* restricted by sg_alloc_table */ 186 if (WARN_ON(overflows_type(PFN_UP(res->size), unsigned int))) 187 return ERR_PTR(-E2BIG); 188 189 if (sg_alloc_table(st, PFN_UP(res->size), GFP_KERNEL)) { 190 i915_refct_sgt_put(rsgt); 191 return ERR_PTR(-ENOMEM); 192 } 193 194 sg = st->sgl; 195 st->nents = 0; 196 prev_end = (resource_size_t)-1; 197 198 list_for_each_entry(block, blocks, link) { 199 u64 block_size, offset; 200 201 block_size = min_t(u64, size, drm_buddy_block_size(mm, block)); 202 offset = drm_buddy_block_offset(block); 203 204 while (block_size) { 205 u64 len; 206 207 if (offset != prev_end || sg->length >= max_segment) { 208 if (st->nents) 209 sg = __sg_next(sg); 210 211 sg_dma_address(sg) = region_start + offset; 212 GEM_BUG_ON(!IS_ALIGNED(sg_dma_address(sg), 213 page_alignment)); 214 sg_dma_len(sg) = 0; 215 sg->length = 0; 216 st->nents++; 217 } 218 219 len = min_t(u64, block_size, max_segment - sg->length); 220 sg->length += len; 221 sg_dma_len(sg) += len; 222 223 offset += len; 224 block_size -= len; 225 226 prev_end = offset; 227 } 228 } 229 230 sg_mark_end(sg); 231 i915_sg_trim(st); 232 233 return rsgt; 234 } 235 236 #if IS_ENABLED(CONFIG_DRM_I915_SELFTEST) 237 #include "selftests/scatterlist.c" 238 #endif 239