1 /* SPDX-License-Identifier: MIT */ 2 /* 3 * Copyright © 2021 Intel Corporation 4 */ 5 6 #ifndef __DRM_BUDDY_H__ 7 #define __DRM_BUDDY_H__ 8 9 #include <linux/bitops.h> 10 #include <linux/list.h> 11 #include <linux/slab.h> 12 #include <linux/sched.h> 13 14 #include <drm/drm_print.h> 15 16 #define range_overflows(start, size, max) ({ \ 17 typeof(start) start__ = (start); \ 18 typeof(size) size__ = (size); \ 19 typeof(max) max__ = (max); \ 20 (void)(&start__ == &size__); \ 21 (void)(&start__ == &max__); \ 22 start__ >= max__ || size__ > max__ - start__; \ 23 }) 24 25 #define DRM_BUDDY_RANGE_ALLOCATION BIT(0) 26 #define DRM_BUDDY_TOPDOWN_ALLOCATION BIT(1) 27 #define DRM_BUDDY_CONTIGUOUS_ALLOCATION BIT(2) 28 #define DRM_BUDDY_CLEAR_ALLOCATION BIT(3) 29 #define DRM_BUDDY_CLEARED BIT(4) 30 31 struct drm_buddy_block { 32 #define DRM_BUDDY_HEADER_OFFSET GENMASK_ULL(63, 12) 33 #define DRM_BUDDY_HEADER_STATE GENMASK_ULL(11, 10) 34 #define DRM_BUDDY_ALLOCATED (1 << 10) 35 #define DRM_BUDDY_FREE (2 << 10) 36 #define DRM_BUDDY_SPLIT (3 << 10) 37 #define DRM_BUDDY_HEADER_CLEAR GENMASK_ULL(9, 9) 38 /* Free to be used, if needed in the future */ 39 #define DRM_BUDDY_HEADER_UNUSED GENMASK_ULL(8, 6) 40 #define DRM_BUDDY_HEADER_ORDER GENMASK_ULL(5, 0) 41 u64 header; 42 43 struct drm_buddy_block *left; 44 struct drm_buddy_block *right; 45 struct drm_buddy_block *parent; 46 47 void *private; /* owned by creator */ 48 49 /* 50 * While the block is allocated by the user through drm_buddy_alloc*, 51 * the user has ownership of the link, for example to maintain within 52 * a list, if so desired. As soon as the block is freed with 53 * drm_buddy_free* ownership is given back to the mm. 54 */ 55 struct list_head link; 56 struct list_head tmp_link; 57 }; 58 59 /* Order-zero must be at least PAGE_SIZE */ 60 #define DRM_BUDDY_MAX_ORDER (63 - PAGE_SHIFT) 61 62 /* 63 * Binary Buddy System. 64 * 65 * Locking should be handled by the user, a simple mutex around 66 * drm_buddy_alloc* and drm_buddy_free* should suffice. 67 */ 68 struct drm_buddy { 69 /* Maintain a free list for each order. */ 70 struct list_head *free_list; 71 72 /* 73 * Maintain explicit binary tree(s) to track the allocation of the 74 * address space. This gives us a simple way of finding a buddy block 75 * and performing the potentially recursive merge step when freeing a 76 * block. Nodes are either allocated or free, in which case they will 77 * also exist on the respective free list. 78 */ 79 struct drm_buddy_block **roots; 80 81 /* 82 * Anything from here is public, and remains static for the lifetime of 83 * the mm. Everything above is considered do-not-touch. 84 */ 85 unsigned int n_roots; 86 unsigned int max_order; 87 88 /* Must be at least PAGE_SIZE */ 89 u64 chunk_size; 90 u64 size; 91 u64 avail; 92 u64 clear_avail; 93 }; 94 95 static inline u64 96 drm_buddy_block_offset(struct drm_buddy_block *block) 97 { 98 return block->header & DRM_BUDDY_HEADER_OFFSET; 99 } 100 101 static inline unsigned int 102 drm_buddy_block_order(struct drm_buddy_block *block) 103 { 104 return block->header & DRM_BUDDY_HEADER_ORDER; 105 } 106 107 static inline unsigned int 108 drm_buddy_block_state(struct drm_buddy_block *block) 109 { 110 return block->header & DRM_BUDDY_HEADER_STATE; 111 } 112 113 static inline bool 114 drm_buddy_block_is_allocated(struct drm_buddy_block *block) 115 { 116 return drm_buddy_block_state(block) == DRM_BUDDY_ALLOCATED; 117 } 118 119 static inline bool 120 drm_buddy_block_is_clear(struct drm_buddy_block *block) 121 { 122 return block->header & DRM_BUDDY_HEADER_CLEAR; 123 } 124 125 static inline bool 126 drm_buddy_block_is_free(struct drm_buddy_block *block) 127 { 128 return drm_buddy_block_state(block) == DRM_BUDDY_FREE; 129 } 130 131 static inline bool 132 drm_buddy_block_is_split(struct drm_buddy_block *block) 133 { 134 return drm_buddy_block_state(block) == DRM_BUDDY_SPLIT; 135 } 136 137 static inline u64 138 drm_buddy_block_size(struct drm_buddy *mm, 139 struct drm_buddy_block *block) 140 { 141 return mm->chunk_size << drm_buddy_block_order(block); 142 } 143 144 int drm_buddy_init(struct drm_buddy *mm, u64 size, u64 chunk_size); 145 146 void drm_buddy_fini(struct drm_buddy *mm); 147 148 struct drm_buddy_block * 149 drm_get_buddy(struct drm_buddy_block *block); 150 151 int drm_buddy_alloc_blocks(struct drm_buddy *mm, 152 u64 start, u64 end, u64 size, 153 u64 min_page_size, 154 struct list_head *blocks, 155 unsigned long flags); 156 157 int drm_buddy_block_trim(struct drm_buddy *mm, 158 u64 new_size, 159 struct list_head *blocks); 160 161 void drm_buddy_free_block(struct drm_buddy *mm, struct drm_buddy_block *block); 162 163 void drm_buddy_free_list(struct drm_buddy *mm, 164 struct list_head *objects, 165 unsigned int flags); 166 167 void drm_buddy_print(struct drm_buddy *mm, struct drm_printer *p); 168 void drm_buddy_block_print(struct drm_buddy *mm, 169 struct drm_buddy_block *block, 170 struct drm_printer *p); 171 #endif 172