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/types.h>
34 #include <linux/spinlock_types.h>
35 #include <linux/atomic.h>
36
37 struct device;
38 struct device_node;
39 struct gen_pool;
40
41 /**
42 * typedef genpool_algo_t: Allocation callback function type definition
43 * @map: Pointer to bitmap
44 * @size: The bitmap size in bits
45 * @start: The bitnumber to start searching at
46 * @nr: The number of zeroed bits we're looking for
47 * @data: optional additional data used by the callback
48 * @pool: the pool being allocated from
49 */
50 typedef unsigned long (*genpool_algo_t)(unsigned long *map,
51 unsigned long size,
52 unsigned long start,
53 unsigned int nr,
54 void *data, struct gen_pool *pool);
55
56 /*
57 * General purpose special memory pool descriptor.
58 */
59 struct gen_pool {
60 spinlock_t lock;
61 struct list_head chunks; /* list of chunks in this pool */
62 int min_alloc_order; /* minimum allocation order */
63
64 genpool_algo_t algo; /* allocation function */
65 void *data;
66
67 const char *name;
68 };
69
70 /*
71 * General purpose special memory pool chunk descriptor.
72 */
73 struct gen_pool_chunk {
74 struct list_head next_chunk; /* next chunk in pool */
75 atomic_long_t avail;
76 phys_addr_t phys_addr; /* physical starting address of memory chunk */
77 unsigned long start_addr; /* start address of memory chunk */
78 unsigned long end_addr; /* end address of memory chunk (inclusive) */
79 unsigned long bits[0]; /* bitmap for allocating memory chunk */
80 };
81
82 /*
83 * gen_pool data descriptor for gen_pool_first_fit_align.
84 */
85 struct genpool_data_align {
86 int align; /* alignment by bytes for starting address */
87 };
88
89 /*
90 * gen_pool data descriptor for gen_pool_fixed_alloc.
91 */
92 struct genpool_data_fixed {
93 unsigned long offset; /* The offset of the specific region */
94 };
95
96 extern struct gen_pool *gen_pool_create(int, int);
97 extern phys_addr_t gen_pool_virt_to_phys(struct gen_pool *pool, unsigned long);
98 extern int gen_pool_add_virt(struct gen_pool *, unsigned long, phys_addr_t,
99 size_t, int);
100 /**
101 * gen_pool_add - add a new chunk of special memory to the pool
102 * @pool: pool to add new memory chunk to
103 * @addr: starting address of memory chunk to add to pool
104 * @size: size in bytes of the memory chunk to add to pool
105 * @nid: node id of the node the chunk structure and bitmap should be
106 * allocated on, or -1
107 *
108 * Add a new chunk of special memory to the specified pool.
109 *
110 * Returns 0 on success or a -ve errno on failure.
111 */
gen_pool_add(struct gen_pool * pool,unsigned long addr,size_t size,int nid)112 static inline int gen_pool_add(struct gen_pool *pool, unsigned long addr,
113 size_t size, int nid)
114 {
115 return gen_pool_add_virt(pool, addr, -1, size, nid);
116 }
117 extern void gen_pool_destroy(struct gen_pool *);
118 extern unsigned long gen_pool_alloc(struct gen_pool *, size_t);
119 extern unsigned long gen_pool_alloc_algo(struct gen_pool *, size_t,
120 genpool_algo_t algo, void *data);
121 extern void *gen_pool_dma_alloc(struct gen_pool *pool, size_t size,
122 dma_addr_t *dma);
123 extern void gen_pool_free(struct gen_pool *, unsigned long, size_t);
124 extern void gen_pool_for_each_chunk(struct gen_pool *,
125 void (*)(struct gen_pool *, struct gen_pool_chunk *, void *), void *);
126 extern size_t gen_pool_avail(struct gen_pool *);
127 extern size_t gen_pool_size(struct gen_pool *);
128
129 extern void gen_pool_set_algo(struct gen_pool *pool, genpool_algo_t algo,
130 void *data);
131
132 extern unsigned long gen_pool_first_fit(unsigned long *map, unsigned long size,
133 unsigned long start, unsigned int nr, void *data,
134 struct gen_pool *pool);
135
136 extern unsigned long gen_pool_fixed_alloc(unsigned long *map,
137 unsigned long size, unsigned long start, unsigned int nr,
138 void *data, struct gen_pool *pool);
139
140 extern unsigned long gen_pool_first_fit_align(unsigned long *map,
141 unsigned long size, unsigned long start, unsigned int nr,
142 void *data, struct gen_pool *pool);
143
144
145 extern unsigned long gen_pool_first_fit_order_align(unsigned long *map,
146 unsigned long size, unsigned long start, unsigned int nr,
147 void *data, struct gen_pool *pool);
148
149 extern unsigned long gen_pool_best_fit(unsigned long *map, unsigned long size,
150 unsigned long start, unsigned int nr, void *data,
151 struct gen_pool *pool);
152
153
154 extern struct gen_pool *devm_gen_pool_create(struct device *dev,
155 int min_alloc_order, int nid, const char *name);
156 extern struct gen_pool *gen_pool_get(struct device *dev, const char *name);
157
158 bool addr_in_gen_pool(struct gen_pool *pool, unsigned long start,
159 size_t size);
160
161 #ifdef CONFIG_OF
162 extern struct gen_pool *of_gen_pool_get(struct device_node *np,
163 const char *propname, int index);
164 #else
of_gen_pool_get(struct device_node * np,const char * propname,int index)165 static inline struct gen_pool *of_gen_pool_get(struct device_node *np,
166 const char *propname, int index)
167 {
168 return NULL;
169 }
170 #endif
171 #endif /* __GENALLOC_H__ */
172
