projects/linux·blob v4.1-rc5 · refs

137 lines · 4.8 KiB

1/*
2 * Basic general purpose allocator for managing special purpose
3 * memory, for example, memory that is not managed by the regular
4 * kmalloc/kfree interface. Uses for this includes on-device special
5 * memory, uncached memory etc.
6 *
7 * It is safe to use the allocator in NMI handlers and other special
8 * unblockable contexts that could otherwise deadlock on locks. This
9 * is implemented by using atomic operations and retries on any
10 * conflicts. The disadvantage is that there may be livelocks in
11 * extreme cases. For better scalability, one allocator can be used
12 * for each CPU.
13 *
14 * The lockless operation only works if there is enough memory
15 * available. If new memory is added to the pool a lock has to be
16 * still taken. So any user relying on locklessness has to ensure
17 * that sufficient memory is preallocated.
18 *
19 * The basic atomic operation of this allocator is cmpxchg on long.
20 * On architectures that don't have NMI-safe cmpxchg implementation,
21 * the allocator can NOT be used in NMI handler. So code uses the
22 * allocator in NMI handler should depend on
23 * CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG.
24 *
25 * This source code is licensed under the GNU General Public License,
26 * Version 2. See the file COPYING for more details.
27 */
28
29
30#ifndef __GENALLOC_H__
31#define __GENALLOC_H__
32
33#include <linux/spinlock_types.h>
34
35struct device;
36struct device_node;
37
38/**
39 * Allocation callback function type definition
40 * @map: Pointer to bitmap
41 * @size: The bitmap size in bits
42 * @start: The bitnumber to start searching at
43 * @nr: The number of zeroed bits we're looking for
44 * @data: optional additional data used by @genpool_algo_t
45 */
46typedef unsigned long (*genpool_algo_t)(unsigned long *map,
47 unsigned long size,
48 unsigned long start,
49 unsigned int nr,
50 void *data);
51
52/*
53 * General purpose special memory pool descriptor.
54 */
55struct gen_pool {
56 spinlock_t lock;
57 struct list_head chunks; /* list of chunks in this pool */
58 int min_alloc_order; /* minimum allocation order */
59
60 genpool_algo_t algo; /* allocation function */
61 void *data;
62};
63
64/*
65 * General purpose special memory pool chunk descriptor.
66 */
67struct gen_pool_chunk {
68 struct list_head next_chunk; /* next chunk in pool */
69 atomic_t avail;
70 phys_addr_t phys_addr; /* physical starting address of memory chunk */
71 unsigned long start_addr; /* start address of memory chunk */
72 unsigned long end_addr; /* end address of memory chunk (inclusive) */
73 unsigned long bits[0]; /* bitmap for allocating memory chunk */
74};
75
76extern struct gen_pool *gen_pool_create(int, int);
77extern phys_addr_t gen_pool_virt_to_phys(struct gen_pool *pool, unsigned long);
78extern int gen_pool_add_virt(struct gen_pool *, unsigned long, phys_addr_t,
79 size_t, int);
80/**
81 * gen_pool_add - add a new chunk of special memory to the pool
82 * @pool: pool to add new memory chunk to
83 * @addr: starting address of memory chunk to add to pool
84 * @size: size in bytes of the memory chunk to add to pool
85 * @nid: node id of the node the chunk structure and bitmap should be
86 * allocated on, or -1
87 *
88 * Add a new chunk of special memory to the specified pool.
89 *
90 * Returns 0 on success or a -ve errno on failure.
91 */
92static inline int gen_pool_add(struct gen_pool *pool, unsigned long addr,
93 size_t size, int nid)
94{
95 return gen_pool_add_virt(pool, addr, -1, size, nid);
96}
97extern void gen_pool_destroy(struct gen_pool *);
98extern unsigned long gen_pool_alloc(struct gen_pool *, size_t);
99extern void *gen_pool_dma_alloc(struct gen_pool *pool, size_t size,
100 dma_addr_t *dma);
101extern void gen_pool_free(struct gen_pool *, unsigned long, size_t);
102extern void gen_pool_for_each_chunk(struct gen_pool *,
103 void (*)(struct gen_pool *, struct gen_pool_chunk *, void *), void *);
104extern size_t gen_pool_avail(struct gen_pool *);
105extern size_t gen_pool_size(struct gen_pool *);
106
107extern void gen_pool_set_algo(struct gen_pool *pool, genpool_algo_t algo,
108 void *data);
109
110extern unsigned long gen_pool_first_fit(unsigned long *map, unsigned long size,
111 unsigned long start, unsigned int nr, void *data);
112
113extern unsigned long gen_pool_first_fit_order_align(unsigned long *map,
114 unsigned long size, unsigned long start, unsigned int nr,
115 void *data);
116
117extern unsigned long gen_pool_best_fit(unsigned long *map, unsigned long size,
118 unsigned long start, unsigned int nr, void *data);
119
120extern struct gen_pool *devm_gen_pool_create(struct device *dev,
121 int min_alloc_order, int nid);
122extern struct gen_pool *dev_get_gen_pool(struct device *dev);
123
124bool addr_in_gen_pool(struct gen_pool *pool, unsigned long start,
125 size_t size);
126
127#ifdef CONFIG_OF
128extern struct gen_pool *of_get_named_gen_pool(struct device_node *np,
129 const char *propname, int index);
130#else
131static inline struct gen_pool *of_get_named_gen_pool(struct device_node *np,
132 const char *propname, int index)
133{
134 return NULL;
135}
136#endif
137#endif /* __GENALLOC_H__ */