xref: /linux/include/linux/genalloc.h (revision ead5d1f4d877e92c051e1a1ade623d0d30e71619)
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 
gen_pool_add_virt(struct gen_pool * pool,unsigned long addr,phys_addr_t phys,size_t size,int nid)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  */
gen_pool_add(struct gen_pool * pool,unsigned long addr,size_t size,int nid)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 
gen_pool_alloc_owner(struct gen_pool * pool,size_t size,void ** owner)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 
gen_pool_alloc_algo(struct gen_pool * pool,size_t size,genpool_algo_t algo,void * data)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  */
gen_pool_alloc(struct gen_pool * pool,size_t size)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);
gen_pool_free(struct gen_pool * pool,unsigned long addr,size_t size)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
of_gen_pool_get(struct device_node * np,const char * propname,int index)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