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.
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
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.
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.
25 * This source code is licensed under the GNU General Public License,
26 * Version 2. See the file COPYING for more details.
30 #ifndef __GENALLOC_H__
31 #define __GENALLOC_H__
33 #include <linux/spinlock_types.h>
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
46 typedef unsigned long (*genpool_algo_t
)(unsigned long *map
,
53 * General purpose special memory pool descriptor.
57 struct list_head chunks
; /* list of chunks in this pool */
58 int min_alloc_order
; /* minimum allocation order */
60 genpool_algo_t algo
; /* allocation function */
65 * General purpose special memory pool chunk descriptor.
67 struct gen_pool_chunk
{
68 struct list_head next_chunk
; /* next chunk in pool */
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 */
76 extern struct gen_pool
*gen_pool_create(int, int);
77 extern phys_addr_t
gen_pool_virt_to_phys(struct gen_pool
*pool
, unsigned long);
78 extern int gen_pool_add_virt(struct gen_pool
*, unsigned long, phys_addr_t
,
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
88 * Add a new chunk of special memory to the specified pool.
90 * Returns 0 on success or a -ve errno on failure.
92 static inline int gen_pool_add(struct gen_pool
*pool
, unsigned long addr
,
95 return gen_pool_add_virt(pool
, addr
, -1, size
, nid
);
97 extern void gen_pool_destroy(struct gen_pool
*);
98 extern unsigned long gen_pool_alloc(struct gen_pool
*, size_t);
99 extern void *gen_pool_dma_alloc(struct gen_pool
*pool
, size_t size
,
101 extern void gen_pool_free(struct gen_pool
*, unsigned long, size_t);
102 extern void gen_pool_for_each_chunk(struct gen_pool
*,
103 void (*)(struct gen_pool
*, struct gen_pool_chunk
*, void *), void *);
104 extern size_t gen_pool_avail(struct gen_pool
*);
105 extern size_t gen_pool_size(struct gen_pool
*);
107 extern void gen_pool_set_algo(struct gen_pool
*pool
, genpool_algo_t algo
,
110 extern unsigned long gen_pool_first_fit(unsigned long *map
, unsigned long size
,
111 unsigned long start
, unsigned int nr
, void *data
);
113 extern unsigned long gen_pool_first_fit_order_align(unsigned long *map
,
114 unsigned long size
, unsigned long start
, unsigned int nr
,
117 extern unsigned long gen_pool_best_fit(unsigned long *map
, unsigned long size
,
118 unsigned long start
, unsigned int nr
, void *data
);
120 extern struct gen_pool
*devm_gen_pool_create(struct device
*dev
,
121 int min_alloc_order
, int nid
);
122 extern struct gen_pool
*dev_get_gen_pool(struct device
*dev
);
124 bool addr_in_gen_pool(struct gen_pool
*pool
, unsigned long start
,
128 extern struct gen_pool
*of_get_named_gen_pool(struct device_node
*np
,
129 const char *propname
, int index
);
131 static inline struct gen_pool
*of_get_named_gen_pool(struct device_node
*np
,
132 const char *propname
, int index
)
137 #endif /* __GENALLOC_H__ */
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