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/* SPDX-License-Identifier: MIT */
/*
* Copyright © 2021 Intel Corporation
*/
#ifndef __DRM_BUDDY_H__
#define __DRM_BUDDY_H__
#include <linux/bitops.h>
#include <linux/list.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <drm/drm_print.h>
#define range_overflows(start, size, max) ({ \
typeof(start) start__ = (start); \
typeof(size) size__ = (size); \
typeof(max) max__ = (max); \
(void)(&start__ == &size__); \
(void)(&start__ == &max__); \
start__ >= max__ || size__ > max__ - start__; \
})
struct drm_buddy_block {
#define DRM_BUDDY_HEADER_OFFSET GENMASK_ULL(63, 12)
#define DRM_BUDDY_HEADER_STATE GENMASK_ULL(11, 10)
#define DRM_BUDDY_ALLOCATED (1 << 10)
#define DRM_BUDDY_FREE (2 << 10)
#define DRM_BUDDY_SPLIT (3 << 10)
/* Free to be used, if needed in the future */
#define DRM_BUDDY_HEADER_UNUSED GENMASK_ULL(9, 6)
#define DRM_BUDDY_HEADER_ORDER GENMASK_ULL(5, 0)
u64 header;
struct drm_buddy_block *left;
struct drm_buddy_block *right;
struct drm_buddy_block *parent;
void *private; /* owned by creator */
/*
* While the block is allocated by the user through drm_buddy_alloc*,
* the user has ownership of the link, for example to maintain within
* a list, if so desired. As soon as the block is freed with
* drm_buddy_free* ownership is given back to the mm.
*/
struct list_head link;
struct list_head tmp_link;
};
/* Order-zero must be at least PAGE_SIZE */
#define DRM_BUDDY_MAX_ORDER (63 - PAGE_SHIFT)
/*
* Binary Buddy System.
*
* Locking should be handled by the user, a simple mutex around
* drm_buddy_alloc* and drm_buddy_free* should suffice.
*/
struct drm_buddy {
/* Maintain a free list for each order. */
struct list_head *free_list;
/*
* Maintain explicit binary tree(s) to track the allocation of the
* address space. This gives us a simple way of finding a buddy block
* and performing the potentially recursive merge step when freeing a
* block. Nodes are either allocated or free, in which case they will
* also exist on the respective free list.
*/
struct drm_buddy_block **roots;
/*
* Anything from here is public, and remains static for the lifetime of
* the mm. Everything above is considered do-not-touch.
*/
unsigned int n_roots;
unsigned int max_order;
/* Must be at least PAGE_SIZE */
u64 chunk_size;
u64 size;
u64 avail;
};
static inline u64
drm_buddy_block_offset(struct drm_buddy_block *block)
{
return block->header & DRM_BUDDY_HEADER_OFFSET;
}
static inline unsigned int
drm_buddy_block_order(struct drm_buddy_block *block)
{
return block->header & DRM_BUDDY_HEADER_ORDER;
}
static inline unsigned int
drm_buddy_block_state(struct drm_buddy_block *block)
{
return block->header & DRM_BUDDY_HEADER_STATE;
}
static inline bool
drm_buddy_block_is_allocated(struct drm_buddy_block *block)
{
return drm_buddy_block_state(block) == DRM_BUDDY_ALLOCATED;
}
static inline bool
drm_buddy_block_is_free(struct drm_buddy_block *block)
{
return drm_buddy_block_state(block) == DRM_BUDDY_FREE;
}
static inline bool
drm_buddy_block_is_split(struct drm_buddy_block *block)
{
return drm_buddy_block_state(block) == DRM_BUDDY_SPLIT;
}
static inline u64
drm_buddy_block_size(struct drm_buddy *mm,
struct drm_buddy_block *block)
{
return mm->chunk_size << drm_buddy_block_order(block);
}
int drm_buddy_init(struct drm_buddy *mm, u64 size, u64 chunk_size);
void drm_buddy_fini(struct drm_buddy *mm);
struct drm_buddy_block *
drm_buddy_alloc_blocks(struct drm_buddy *mm, unsigned int order);
int drm_buddy_alloc_range(struct drm_buddy *mm,
struct list_head *blocks,
u64 start, u64 size);
void drm_buddy_free_block(struct drm_buddy *mm, struct drm_buddy_block *block);
void drm_buddy_free_list(struct drm_buddy *mm, struct list_head *objects);
void drm_buddy_print(struct drm_buddy *mm, struct drm_printer *p);
void drm_buddy_block_print(struct drm_buddy *mm,
struct drm_buddy_block *block,
struct drm_printer *p);
#endif
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