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 #include <linux/atomic.h>
35
36 struct device;
37 struct device_node;
38
39 /**
40 * Allocation callback function type definition
41 * @map: Pointer to bitmap
42 * @size: The bitmap size in bits
43 * @start: The bitnumber to start searching at
44 * @nr: The number of zeroed bits we're looking for
45 * @data: optional additional data used by @genpool_algo_t
46 */
47 typedef unsigned long (*genpool_algo_t)(unsigned long *map,
48 unsigned long size,
49 unsigned long start,
50 unsigned int nr,
51 void *data);
52
53 /*
54 * General purpose special memory pool descriptor.
55 */
56 struct gen_pool {
57 spinlock_t lock;
58 struct list_head chunks; /* list of chunks in this pool */
59 int min_alloc_order; /* minimum allocation order */
60
61 genpool_algo_t algo; /* allocation function */
62 void *data;
63 };
64
65 /*
66 * General purpose special memory pool chunk descriptor.
67 */
68 struct gen_pool_chunk {
69 struct list_head next_chunk; /* next chunk in pool */
70 atomic_long_t avail;
71 phys_addr_t phys_addr; /* physical starting address of memory chunk */
72 unsigned long start_addr; /* start address of memory chunk */
73 unsigned long end_addr; /* end address of memory chunk (inclusive) */
74 unsigned long bits[0]; /* bitmap for allocating memory chunk */
75 };
76
77 extern struct gen_pool *gen_pool_create(int, int);
78 extern phys_addr_t gen_pool_virt_to_phys(struct gen_pool *pool, unsigned long);
79 extern int gen_pool_add_virt(struct gen_pool *, unsigned long, phys_addr_t,
80 size_t, int);
81 /**
82 * gen_pool_add - add a new chunk of special memory to the pool
83 * @pool: pool to add new memory chunk to
84 * @addr: starting address of memory chunk to add to pool
85 * @size: size in bytes of the memory chunk to add to pool
86 * @nid: node id of the node the chunk structure and bitmap should be
87 * allocated on, or -1
88 *
89 * Add a new chunk of special memory to the specified pool.
90 *
91 * Returns 0 on success or a -ve errno on failure.
92 */
gen_pool_add(struct gen_pool * pool,unsigned long addr,size_t size,int nid)93 static inline int gen_pool_add(struct gen_pool *pool, unsigned long addr,
94 size_t size, int nid)
95 {
96 return gen_pool_add_virt(pool, addr, -1, size, nid);
97 }
98 extern void gen_pool_destroy(struct gen_pool *);
99 extern unsigned long gen_pool_alloc(struct gen_pool *, size_t);
100 extern void *gen_pool_dma_alloc(struct gen_pool *pool, size_t size,
101 dma_addr_t *dma);
102 extern void gen_pool_free(struct gen_pool *, unsigned long, size_t);
103 extern void gen_pool_for_each_chunk(struct gen_pool *,
104 void (*)(struct gen_pool *, struct gen_pool_chunk *, void *), void *);
105 extern size_t gen_pool_avail(struct gen_pool *);
106 extern size_t gen_pool_size(struct gen_pool *);
107
108 extern void gen_pool_set_algo(struct gen_pool *pool, genpool_algo_t algo,
109 void *data);
110
111 extern unsigned long gen_pool_first_fit(unsigned long *map, unsigned long size,
112 unsigned long start, unsigned int nr, void *data);
113
114 extern unsigned long gen_pool_first_fit_order_align(unsigned long *map,
115 unsigned long size, unsigned long start, unsigned int nr,
116 void *data);
117
118 extern unsigned long gen_pool_best_fit(unsigned long *map, unsigned long size,
119 unsigned long start, unsigned int nr, void *data);
120
121 extern struct gen_pool *devm_gen_pool_create(struct device *dev,
122 int min_alloc_order, int nid);
123 extern struct gen_pool *dev_get_gen_pool(struct device *dev);
124
125 bool addr_in_gen_pool(struct gen_pool *pool, unsigned long start,
126 size_t size);
127
128 #ifdef CONFIG_OF
129 extern struct gen_pool *of_get_named_gen_pool(struct device_node *np,
130 const char *propname, int index);
131 #else
of_get_named_gen_pool(struct device_node * np,const char * propname,int index)132 static inline struct gen_pool *of_get_named_gen_pool(struct device_node *np,
133 const char *propname, int index)
134 {
135 return NULL;
136 }
137 #endif
138 #endif /* __GENALLOC_H__ */
139