1 /* SPDX-License-Identifier: MIT */
3 * Copyright © 2021 Intel Corporation
6 #ifndef __DRM_BUDDY_H__
7 #define __DRM_BUDDY_H__
9 #include <linux/bitops.h>
10 #include <linux/list.h>
11 #include <linux/slab.h>
12 #include <linux/sched.h>
14 #include <drm/drm_print.h>
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__; \
25 #define DRM_BUDDY_RANGE_ALLOCATION (1 << 0)
26 #define DRM_BUDDY_TOPDOWN_ALLOCATION (1 << 1)
28 struct drm_buddy_block {
29 #define DRM_BUDDY_HEADER_OFFSET GENMASK_ULL(63, 12)
30 #define DRM_BUDDY_HEADER_STATE GENMASK_ULL(11, 10)
31 #define DRM_BUDDY_ALLOCATED (1 << 10)
32 #define DRM_BUDDY_FREE (2 << 10)
33 #define DRM_BUDDY_SPLIT (3 << 10)
34 /* Free to be used, if needed in the future */
35 #define DRM_BUDDY_HEADER_UNUSED GENMASK_ULL(9, 6)
36 #define DRM_BUDDY_HEADER_ORDER GENMASK_ULL(5, 0)
39 struct drm_buddy_block *left;
40 struct drm_buddy_block *right;
41 struct drm_buddy_block *parent;
43 void *private; /* owned by creator */
46 * While the block is allocated by the user through drm_buddy_alloc*,
47 * the user has ownership of the link, for example to maintain within
48 * a list, if so desired. As soon as the block is freed with
49 * drm_buddy_free* ownership is given back to the mm.
51 struct list_head link;
52 struct list_head tmp_link;
55 /* Order-zero must be at least PAGE_SIZE */
56 #define DRM_BUDDY_MAX_ORDER (63 - PAGE_SHIFT)
59 * Binary Buddy System.
61 * Locking should be handled by the user, a simple mutex around
62 * drm_buddy_alloc* and drm_buddy_free* should suffice.
65 /* Maintain a free list for each order. */
66 struct list_head *free_list;
69 * Maintain explicit binary tree(s) to track the allocation of the
70 * address space. This gives us a simple way of finding a buddy block
71 * and performing the potentially recursive merge step when freeing a
72 * block. Nodes are either allocated or free, in which case they will
73 * also exist on the respective free list.
75 struct drm_buddy_block **roots;
78 * Anything from here is public, and remains static for the lifetime of
79 * the mm. Everything above is considered do-not-touch.
82 unsigned int max_order;
84 /* Must be at least PAGE_SIZE */
91 drm_buddy_block_offset(struct drm_buddy_block *block)
93 return block->header & DRM_BUDDY_HEADER_OFFSET;
96 static inline unsigned int
97 drm_buddy_block_order(struct drm_buddy_block *block)
99 return block->header & DRM_BUDDY_HEADER_ORDER;
102 static inline unsigned int
103 drm_buddy_block_state(struct drm_buddy_block *block)
105 return block->header & DRM_BUDDY_HEADER_STATE;
109 drm_buddy_block_is_allocated(struct drm_buddy_block *block)
111 return drm_buddy_block_state(block) == DRM_BUDDY_ALLOCATED;
115 drm_buddy_block_is_free(struct drm_buddy_block *block)
117 return drm_buddy_block_state(block) == DRM_BUDDY_FREE;
121 drm_buddy_block_is_split(struct drm_buddy_block *block)
123 return drm_buddy_block_state(block) == DRM_BUDDY_SPLIT;
127 drm_buddy_block_size(struct drm_buddy *mm,
128 struct drm_buddy_block *block)
130 return mm->chunk_size << drm_buddy_block_order(block);
133 int drm_buddy_init(struct drm_buddy *mm, u64 size, u64 chunk_size);
135 void drm_buddy_fini(struct drm_buddy *mm);
137 struct drm_buddy_block *
138 drm_get_buddy(struct drm_buddy_block *block);
140 int drm_buddy_alloc_blocks(struct drm_buddy *mm,
141 u64 start, u64 end, u64 size,
143 struct list_head *blocks,
144 unsigned long flags);
146 int drm_buddy_block_trim(struct drm_buddy *mm,
148 struct list_head *blocks);
150 void drm_buddy_free_block(struct drm_buddy *mm, struct drm_buddy_block *block);
152 void drm_buddy_free_list(struct drm_buddy *mm, struct list_head *objects);
154 void drm_buddy_print(struct drm_buddy *mm, struct drm_printer *p);
155 void drm_buddy_block_print(struct drm_buddy *mm,
156 struct drm_buddy_block *block,
157 struct drm_printer *p);