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 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)
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)
43 struct drm_buddy_block *left;
44 struct drm_buddy_block *right;
45 struct drm_buddy_block *parent;
47 void *private; /* owned by creator */
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.
55 struct list_head link;
56 struct list_head tmp_link;
59 /* Order-zero must be at least SZ_4K */
60 #define DRM_BUDDY_MAX_ORDER (63 - 12)
63 * Binary Buddy System.
65 * Locking should be handled by the user, a simple mutex around
66 * drm_buddy_alloc* and drm_buddy_free* should suffice.
69 /* Maintain a free list for each order. */
70 struct list_head *free_list;
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.
79 struct drm_buddy_block **roots;
82 * Anything from here is public, and remains static for the lifetime of
83 * the mm. Everything above is considered do-not-touch.
86 unsigned int max_order;
88 /* Must be at least SZ_4K */
96 drm_buddy_block_offset(struct drm_buddy_block *block)
98 return block->header & DRM_BUDDY_HEADER_OFFSET;
101 static inline unsigned int
102 drm_buddy_block_order(struct drm_buddy_block *block)
104 return block->header & DRM_BUDDY_HEADER_ORDER;
107 static inline unsigned int
108 drm_buddy_block_state(struct drm_buddy_block *block)
110 return block->header & DRM_BUDDY_HEADER_STATE;
114 drm_buddy_block_is_allocated(struct drm_buddy_block *block)
116 return drm_buddy_block_state(block) == DRM_BUDDY_ALLOCATED;
120 drm_buddy_block_is_clear(struct drm_buddy_block *block)
122 return block->header & DRM_BUDDY_HEADER_CLEAR;
126 drm_buddy_block_is_free(struct drm_buddy_block *block)
128 return drm_buddy_block_state(block) == DRM_BUDDY_FREE;
132 drm_buddy_block_is_split(struct drm_buddy_block *block)
134 return drm_buddy_block_state(block) == DRM_BUDDY_SPLIT;
138 drm_buddy_block_size(struct drm_buddy *mm,
139 struct drm_buddy_block *block)
141 return mm->chunk_size << drm_buddy_block_order(block);
144 int drm_buddy_init(struct drm_buddy *mm, u64 size, u64 chunk_size);
146 void drm_buddy_fini(struct drm_buddy *mm);
148 struct drm_buddy_block *
149 drm_get_buddy(struct drm_buddy_block *block);
151 int drm_buddy_alloc_blocks(struct drm_buddy *mm,
152 u64 start, u64 end, u64 size,
154 struct list_head *blocks,
155 unsigned long flags);
157 int drm_buddy_block_trim(struct drm_buddy *mm,
159 struct list_head *blocks);
161 void drm_buddy_free_block(struct drm_buddy *mm, struct drm_buddy_block *block);
163 void drm_buddy_free_list(struct drm_buddy *mm,
164 struct list_head *objects,
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);