1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3 * Basic general purpose allocator for managing special purpose
4 * memory, for example, memory that is not managed by the regular
5 * kmalloc/kfree interface. Uses for this includes on-device special
6 * memory, uncached memory etc.
7 *
8 * It is safe to use the allocator in NMI handlers and other special
9 * unblockable contexts that could otherwise deadlock on locks. This
10 * is implemented by using atomic operations and retries on any
11 * conflicts. The disadvantage is that there may be livelocks in
12 * extreme cases. For better scalability, one allocator can be used
13 * for each CPU.
14 *
15 * The lockless operation only works if there is enough memory
16 * available. If new memory is added to the pool a lock has to be
17 * still taken. So any user relying on locklessness has to ensure
18 * that sufficient memory is preallocated.
19 *
20 * The basic atomic operation of this allocator is cmpxchg on long.
21 * On architectures that don't have NMI-safe cmpxchg implementation,
22 * the allocator can NOT be used in NMI handler. So code uses the
23 * allocator in NMI handler should depend on
24 * CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG.
25 */
26
27
28 #ifndef __GENALLOC_H__
29 #define __GENALLOC_H__
30
31 #include <linux/types.h>
32 #include <linux/spinlock_types.h>
33 #include <linux/atomic.h>
34
35 struct device;
36 struct device_node;
37 struct gen_pool;
38
39 /**
40 * typedef genpool_algo_t: 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 the callback
46 * @pool: the pool being allocated from
47 */
48 typedef unsigned long (*genpool_algo_t)(unsigned long *map,
49 unsigned long size,
50 unsigned long start,
51 unsigned int nr,
52 void *data, struct gen_pool *pool,
53 unsigned long start_addr);
54
55 /*
56 * General purpose special memory pool descriptor.
57 */
58 struct gen_pool {
59 spinlock_t lock;
60 struct list_head chunks; /* list of chunks in this pool */
61 int min_alloc_order; /* minimum allocation order */
62
63 genpool_algo_t algo; /* allocation function */
64 void *data;
65
66 const char *name;
67 };
68
69 /*
70 * General purpose special memory pool chunk descriptor.
71 */
72 struct gen_pool_chunk {
73 struct list_head next_chunk; /* next chunk in pool */
74 atomic_long_t avail;
75 phys_addr_t phys_addr; /* physical starting address of memory chunk */
76 void *owner; /* private data to retrieve at alloc time */
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[]; /* 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_owner(struct gen_pool *, unsigned long, phys_addr_t,
99 size_t, int, void *);
100
101 static inline int gen_pool_add_virt(struct gen_pool *pool, unsigned long addr,
102 phys_addr_t phys, size_t size, int nid)
103 {
104 return gen_pool_add_owner(pool, addr, phys, size, nid, NULL);
105 }
106
107 /**
108 * gen_pool_add - add a new chunk of special memory to the pool
109 * @pool: pool to add new memory chunk to
110 * @addr: starting address of memory chunk to add to pool
111 * @size: size in bytes of the memory chunk to add to pool
112 * @nid: node id of the node the chunk structure and bitmap should be
113 * allocated on, or -1
114 *
115 * Add a new chunk of special memory to the specified pool.
116 *
117 * Returns 0 on success or a -ve errno on failure.
118 */
119 static inline int gen_pool_add(struct gen_pool *pool, unsigned long addr,
120 size_t size, int nid)
121 {
122 return gen_pool_add_virt(pool, addr, -1, size, nid);
123 }
124 extern void gen_pool_destroy(struct gen_pool *);
125 unsigned long gen_pool_alloc_algo_owner(struct gen_pool *pool, size_t size,
126 genpool_algo_t algo, void *data, void **owner);
127
128 static inline unsigned long gen_pool_alloc_owner(struct gen_pool *pool,
129 size_t size, void **owner)
130 {
131 return gen_pool_alloc_algo_owner(pool, size, pool->algo, pool->data,
132 owner);
133 }
134
135 static inline unsigned long gen_pool_alloc_algo(struct gen_pool *pool,
136 size_t size, genpool_algo_t algo, void *data)
137 {
138 return gen_pool_alloc_algo_owner(pool, size, algo, data, NULL);
139 }
140
141 /**
142 * gen_pool_alloc - allocate special memory from the pool
143 * @pool: pool to allocate from
144 * @size: number of bytes to allocate from the pool
145 *
146 * Allocate the requested number of bytes from the specified pool.
147 * Uses the pool allocation function (with first-fit algorithm by default).
148 * Can not be used in NMI handler on architectures without
149 * NMI-safe cmpxchg implementation.
150 */
151 static inline unsigned long gen_pool_alloc(struct gen_pool *pool, size_t size)
152 {
153 return gen_pool_alloc_algo(pool, size, pool->algo, pool->data);
154 }
155
156 extern void *gen_pool_dma_alloc(struct gen_pool *pool, size_t size,
157 dma_addr_t *dma);
158 extern void *gen_pool_dma_alloc_algo(struct gen_pool *pool, size_t size,
159 dma_addr_t *dma, genpool_algo_t algo, void *data);
160 extern void *gen_pool_dma_alloc_align(struct gen_pool *pool, size_t size,
161 dma_addr_t *dma, int align);
162 extern void *gen_pool_dma_zalloc(struct gen_pool *pool, size_t size, dma_addr_t *dma);
163 extern void *gen_pool_dma_zalloc_algo(struct gen_pool *pool, size_t size,
164 dma_addr_t *dma, genpool_algo_t algo, void *data);
165 extern void *gen_pool_dma_zalloc_align(struct gen_pool *pool, size_t size,
166 dma_addr_t *dma, int align);
167 extern void gen_pool_free_owner(struct gen_pool *pool, unsigned long addr,
168 size_t size, void **owner);
169 static inline void gen_pool_free(struct gen_pool *pool, unsigned long addr,
170 size_t size)
171 {
172 gen_pool_free_owner(pool, addr, size, NULL);
173 }
174
175 extern void gen_pool_for_each_chunk(struct gen_pool *,
176 void (*)(struct gen_pool *, struct gen_pool_chunk *, void *), void *);
177 extern size_t gen_pool_avail(struct gen_pool *);
178 extern size_t gen_pool_size(struct gen_pool *);
179
180 extern void gen_pool_set_algo(struct gen_pool *pool, genpool_algo_t algo,
181 void *data);
182
183 extern unsigned long gen_pool_first_fit(unsigned long *map, unsigned long size,
184 unsigned long start, unsigned int nr, void *data,
185 struct gen_pool *pool, unsigned long start_addr);
186
187 extern unsigned long gen_pool_fixed_alloc(unsigned long *map,
188 unsigned long size, unsigned long start, unsigned int nr,
189 void *data, struct gen_pool *pool, unsigned long start_addr);
190
191 extern unsigned long gen_pool_first_fit_align(unsigned long *map,
192 unsigned long size, unsigned long start, unsigned int nr,
193 void *data, struct gen_pool *pool, unsigned long start_addr);
194
195
196 extern unsigned long gen_pool_first_fit_order_align(unsigned long *map,
197 unsigned long size, unsigned long start, unsigned int nr,
198 void *data, struct gen_pool *pool, unsigned long start_addr);
199
200 extern unsigned long gen_pool_best_fit(unsigned long *map, unsigned long size,
201 unsigned long start, unsigned int nr, void *data,
202 struct gen_pool *pool, unsigned long start_addr);
203
204
205 extern struct gen_pool *devm_gen_pool_create(struct device *dev,
206 int min_alloc_order, int nid, const char *name);
207 extern struct gen_pool *gen_pool_get(struct device *dev, const char *name);
208
209 extern bool gen_pool_has_addr(struct gen_pool *pool, unsigned long start,
210 size_t size);
211
212 #ifdef CONFIG_OF
213 extern struct gen_pool *of_gen_pool_get(struct device_node *np,
214 const char *propname, int index);
215 #else
216 static inline struct gen_pool *of_gen_pool_get(struct device_node *np,
217 const char *propname, int index)
218 {
219 return NULL;
220 }
221 #endif
222 #endif /* __GENALLOC_H__ */
223
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