genalloc.h 4.43 KB
Newer Older
Jes Sorensen's avatar
Jes Sorensen committed
1
/*
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
 * Basic general purpose allocator for managing special purpose
 * memory, for example, memory that is not managed by the regular
 * kmalloc/kfree interface.  Uses for this includes on-device special
 * memory, uncached memory etc.
 *
 * It is safe to use the allocator in NMI handlers and other special
 * unblockable contexts that could otherwise deadlock on locks.  This
 * is implemented by using atomic operations and retries on any
 * conflicts.  The disadvantage is that there may be livelocks in
 * extreme cases.  For better scalability, one allocator can be used
 * for each CPU.
 *
 * The lockless operation only works if there is enough memory
 * available.  If new memory is added to the pool a lock has to be
 * still taken.  So any user relying on locklessness has to ensure
 * that sufficient memory is preallocated.
 *
 * The basic atomic operation of this allocator is cmpxchg on long.
 * On architectures that don't have NMI-safe cmpxchg implementation,
 * the allocator can NOT be used in NMI handler.  So code uses the
 * allocator in NMI handler should depend on
 * CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG.
Jes Sorensen's avatar
Jes Sorensen committed
24
25
26
27
28
29
 *
 * This source code is licensed under the GNU General Public License,
 * Version 2.  See the file COPYING for more details.
 */


30
31
#ifndef __GENALLOC_H__
#define __GENALLOC_H__
32
33
34
35

struct device;
struct device_node;

36
37
38
39
40
41
42
43
44
45
46
47
48
49
/**
 * Allocation callback function type definition
 * @map: Pointer to bitmap
 * @size: The bitmap size in bits
 * @start: The bitnumber to start searching at
 * @nr: The number of zeroed bits we're looking for
 * @data: optional additional data used by @genpool_algo_t
 */
typedef unsigned long (*genpool_algo_t)(unsigned long *map,
			unsigned long size,
			unsigned long start,
			unsigned int nr,
			void *data);

Jes Sorensen's avatar
Jes Sorensen committed
50
/*
51
 *  General purpose special memory pool descriptor.
Jes Sorensen's avatar
Jes Sorensen committed
52
 */
53
struct gen_pool {
54
	spinlock_t lock;
55
56
	struct list_head chunks;	/* list of chunks in this pool */
	int min_alloc_order;		/* minimum allocation order */
57
58
59

	genpool_algo_t algo;		/* allocation function */
	void *data;
Jes Sorensen's avatar
Jes Sorensen committed
60
61
62
};

/*
63
 *  General purpose special memory pool chunk descriptor.
Jes Sorensen's avatar
Jes Sorensen committed
64
 */
65
66
struct gen_pool_chunk {
	struct list_head next_chunk;	/* next chunk in pool */
67
	atomic_t avail;
68
	phys_addr_t phys_addr;		/* physical starting address of memory chunk */
69
70
	unsigned long start_addr;	/* start address of memory chunk */
	unsigned long end_addr;		/* end address of memory chunk (inclusive) */
71
	unsigned long bits[0];		/* bitmap for allocating memory chunk */
Jes Sorensen's avatar
Jes Sorensen committed
72
73
};

74
extern struct gen_pool *gen_pool_create(int, int);
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
extern phys_addr_t gen_pool_virt_to_phys(struct gen_pool *pool, unsigned long);
extern int gen_pool_add_virt(struct gen_pool *, unsigned long, phys_addr_t,
			     size_t, int);
/**
 * gen_pool_add - add a new chunk of special memory to the pool
 * @pool: pool to add new memory chunk to
 * @addr: starting address of memory chunk to add to pool
 * @size: size in bytes of the memory chunk to add to pool
 * @nid: node id of the node the chunk structure and bitmap should be
 *       allocated on, or -1
 *
 * Add a new chunk of special memory to the specified pool.
 *
 * Returns 0 on success or a -ve errno on failure.
 */
static inline int gen_pool_add(struct gen_pool *pool, unsigned long addr,
			       size_t size, int nid)
{
	return gen_pool_add_virt(pool, addr, -1, size, nid);
}
95
extern void gen_pool_destroy(struct gen_pool *);
96
97
extern unsigned long gen_pool_alloc(struct gen_pool *, size_t);
extern void gen_pool_free(struct gen_pool *, unsigned long, size_t);
98
99
100
101
extern void gen_pool_for_each_chunk(struct gen_pool *,
	void (*)(struct gen_pool *, struct gen_pool_chunk *, void *), void *);
extern size_t gen_pool_avail(struct gen_pool *);
extern size_t gen_pool_size(struct gen_pool *);
102
103
104
105
106
107
108
109
110
111

extern void gen_pool_set_algo(struct gen_pool *pool, genpool_algo_t algo,
		void *data);

extern unsigned long gen_pool_first_fit(unsigned long *map, unsigned long size,
		unsigned long start, unsigned int nr, void *data);

extern unsigned long gen_pool_best_fit(unsigned long *map, unsigned long size,
		unsigned long start, unsigned int nr, void *data);

112
113
114
115
116
117
118
119
120
121
122
123
124
125
extern struct gen_pool *devm_gen_pool_create(struct device *dev,
		int min_alloc_order, int nid);
extern struct gen_pool *dev_get_gen_pool(struct device *dev);

#ifdef CONFIG_OF
extern struct gen_pool *of_get_named_gen_pool(struct device_node *np,
	const char *propname, int index);
#else
static inline struct gen_pool *of_get_named_gen_pool(struct device_node *np,
	const char *propname, int index)
{
	return NULL;
}
#endif
126
#endif /* __GENALLOC_H__ */