Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
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
33struct device;
34struct device_node;
35
36/**
37 * Allocation callback function type definition
38 * @map: Pointer to bitmap
39 * @size: The bitmap size in bits
40 * @start: The bitnumber to start searching at
41 * @nr: The number of zeroed bits we're looking for
42 * @data: optional additional data used by @genpool_algo_t
43 */
44typedef unsigned long (*genpool_algo_t)(unsigned long *map,
45 unsigned long size,
46 unsigned long start,
47 unsigned int nr,
48 void *data);
49
50/*
51 * General purpose special memory pool descriptor.
52 */
53struct gen_pool {
54 spinlock_t lock;
55 struct list_head chunks; /* list of chunks in this pool */
56 int min_alloc_order; /* minimum allocation order */
57
58 genpool_algo_t algo; /* allocation function */
59 void *data;
60};
61
62/*
63 * General purpose special memory pool chunk descriptor.
64 */
65struct gen_pool_chunk {
66 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 unsigned long start_addr; /* start address of memory chunk */
70 unsigned long end_addr; /* end address of memory chunk (inclusive) */
71 unsigned long bits[0]; /* bitmap for allocating memory chunk */
72};
73
74extern struct gen_pool *gen_pool_create(int, int);
75extern phys_addr_t gen_pool_virt_to_phys(struct gen_pool *pool, unsigned long);
76extern int gen_pool_add_virt(struct gen_pool *, unsigned long, phys_addr_t,
77 size_t, int);
78/**
79 * gen_pool_add - add a new chunk of special memory to the pool
80 * @pool: pool to add new memory chunk to
81 * @addr: starting address of memory chunk to add to pool
82 * @size: size in bytes of the memory chunk to add to pool
83 * @nid: node id of the node the chunk structure and bitmap should be
84 * allocated on, or -1
85 *
86 * Add a new chunk of special memory to the specified pool.
87 *
88 * Returns 0 on success or a -ve errno on failure.
89 */
90static inline int gen_pool_add(struct gen_pool *pool, unsigned long addr,
91 size_t size, int nid)
92{
93 return gen_pool_add_virt(pool, addr, -1, size, nid);
94}
95extern void gen_pool_destroy(struct gen_pool *);
96extern unsigned long gen_pool_alloc(struct gen_pool *, size_t);
97extern void *gen_pool_dma_alloc(struct gen_pool *pool, size_t size,
98 dma_addr_t *dma);
99extern void gen_pool_free(struct gen_pool *, unsigned long, size_t);
100extern void gen_pool_for_each_chunk(struct gen_pool *,
101 void (*)(struct gen_pool *, struct gen_pool_chunk *, void *), void *);
102extern size_t gen_pool_avail(struct gen_pool *);
103extern size_t gen_pool_size(struct gen_pool *);
104
105extern void gen_pool_set_algo(struct gen_pool *pool, genpool_algo_t algo,
106 void *data);
107
108extern unsigned long gen_pool_first_fit(unsigned long *map, unsigned long size,
109 unsigned long start, unsigned int nr, void *data);
110
111extern unsigned long gen_pool_best_fit(unsigned long *map, unsigned long size,
112 unsigned long start, unsigned int nr, void *data);
113
114extern struct gen_pool *devm_gen_pool_create(struct device *dev,
115 int min_alloc_order, int nid);
116extern struct gen_pool *dev_get_gen_pool(struct device *dev);
117
118#ifdef CONFIG_OF
119extern struct gen_pool *of_get_named_gen_pool(struct device_node *np,
120 const char *propname, int index);
121#else
122static inline struct gen_pool *of_get_named_gen_pool(struct device_node *np,
123 const char *propname, int index)
124{
125 return NULL;
126}
127#endif
128#endif /* __GENALLOC_H__ */