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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
35struct device;
36struct device_node;
37struct 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 * @start_addr: start address of memory chunk
48 */
49typedef unsigned long (*genpool_algo_t)(unsigned long *map,
50 unsigned long size,
51 unsigned long start,
52 unsigned int nr,
53 void *data, struct gen_pool *pool,
54 unsigned long start_addr);
55
56/*
57 * General purpose special memory pool descriptor.
58 */
59struct 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 */
73struct 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 void *owner; /* private data to retrieve at alloc time */
78 unsigned long start_addr; /* start address of memory chunk */
79 unsigned long end_addr; /* end address of memory chunk (inclusive) */
80 unsigned long bits[]; /* bitmap for allocating memory chunk */
81};
82
83/*
84 * gen_pool data descriptor for gen_pool_first_fit_align.
85 */
86struct genpool_data_align {
87 int align; /* alignment by bytes for starting address */
88};
89
90/*
91 * gen_pool data descriptor for gen_pool_fixed_alloc.
92 */
93struct genpool_data_fixed {
94 unsigned long offset; /* The offset of the specific region */
95};
96
97extern struct gen_pool *gen_pool_create(int, int);
98extern phys_addr_t gen_pool_virt_to_phys(struct gen_pool *pool, unsigned long);
99extern int gen_pool_add_owner(struct gen_pool *, unsigned long, phys_addr_t,
100 size_t, int, void *);
101
102static inline int gen_pool_add_virt(struct gen_pool *pool, unsigned long addr,
103 phys_addr_t phys, size_t size, int nid)
104{
105 return gen_pool_add_owner(pool, addr, phys, size, nid, NULL);
106}
107
108/**
109 * gen_pool_add - add a new chunk of special memory to the pool
110 * @pool: pool to add new memory chunk to
111 * @addr: starting address of memory chunk to add to pool
112 * @size: size in bytes of the memory chunk to add to pool
113 * @nid: node id of the node the chunk structure and bitmap should be
114 * allocated on, or -1
115 *
116 * Add a new chunk of special memory to the specified pool.
117 *
118 * Returns 0 on success or a -ve errno on failure.
119 */
120static inline int gen_pool_add(struct gen_pool *pool, unsigned long addr,
121 size_t size, int nid)
122{
123 return gen_pool_add_virt(pool, addr, -1, size, nid);
124}
125extern void gen_pool_destroy(struct gen_pool *);
126unsigned long gen_pool_alloc_algo_owner(struct gen_pool *pool, size_t size,
127 genpool_algo_t algo, void *data, void **owner);
128
129static inline unsigned long gen_pool_alloc_owner(struct gen_pool *pool,
130 size_t size, void **owner)
131{
132 return gen_pool_alloc_algo_owner(pool, size, pool->algo, pool->data,
133 owner);
134}
135
136static inline unsigned long gen_pool_alloc_algo(struct gen_pool *pool,
137 size_t size, genpool_algo_t algo, void *data)
138{
139 return gen_pool_alloc_algo_owner(pool, size, algo, data, NULL);
140}
141
142/**
143 * gen_pool_alloc - allocate special memory from the pool
144 * @pool: pool to allocate from
145 * @size: number of bytes to allocate from the pool
146 *
147 * Allocate the requested number of bytes from the specified pool.
148 * Uses the pool allocation function (with first-fit algorithm by default).
149 * Can not be used in NMI handler on architectures without
150 * NMI-safe cmpxchg implementation.
151 */
152static inline unsigned long gen_pool_alloc(struct gen_pool *pool, size_t size)
153{
154 return gen_pool_alloc_algo(pool, size, pool->algo, pool->data);
155}
156
157extern void *gen_pool_dma_alloc(struct gen_pool *pool, size_t size,
158 dma_addr_t *dma);
159extern void *gen_pool_dma_alloc_algo(struct gen_pool *pool, size_t size,
160 dma_addr_t *dma, genpool_algo_t algo, void *data);
161extern void *gen_pool_dma_alloc_align(struct gen_pool *pool, size_t size,
162 dma_addr_t *dma, int align);
163extern void *gen_pool_dma_zalloc(struct gen_pool *pool, size_t size, dma_addr_t *dma);
164extern void *gen_pool_dma_zalloc_algo(struct gen_pool *pool, size_t size,
165 dma_addr_t *dma, genpool_algo_t algo, void *data);
166extern void *gen_pool_dma_zalloc_align(struct gen_pool *pool, size_t size,
167 dma_addr_t *dma, int align);
168extern void gen_pool_free_owner(struct gen_pool *pool, unsigned long addr,
169 size_t size, void **owner);
170static inline void gen_pool_free(struct gen_pool *pool, unsigned long addr,
171 size_t size)
172{
173 gen_pool_free_owner(pool, addr, size, NULL);
174}
175
176extern void gen_pool_for_each_chunk(struct gen_pool *,
177 void (*)(struct gen_pool *, struct gen_pool_chunk *, void *), void *);
178extern size_t gen_pool_avail(struct gen_pool *);
179extern size_t gen_pool_size(struct gen_pool *);
180
181extern void gen_pool_set_algo(struct gen_pool *pool, genpool_algo_t algo,
182 void *data);
183
184extern unsigned long gen_pool_first_fit(unsigned long *map, unsigned long size,
185 unsigned long start, unsigned int nr, void *data,
186 struct gen_pool *pool, unsigned long start_addr);
187
188extern unsigned long gen_pool_fixed_alloc(unsigned long *map,
189 unsigned long size, unsigned long start, unsigned int nr,
190 void *data, struct gen_pool *pool, unsigned long start_addr);
191
192extern unsigned long gen_pool_first_fit_align(unsigned long *map,
193 unsigned long size, unsigned long start, unsigned int nr,
194 void *data, struct gen_pool *pool, unsigned long start_addr);
195
196
197extern unsigned long gen_pool_first_fit_order_align(unsigned long *map,
198 unsigned long size, unsigned long start, unsigned int nr,
199 void *data, struct gen_pool *pool, unsigned long start_addr);
200
201extern unsigned long gen_pool_best_fit(unsigned long *map, unsigned long size,
202 unsigned long start, unsigned int nr, void *data,
203 struct gen_pool *pool, unsigned long start_addr);
204
205
206extern struct gen_pool *devm_gen_pool_create(struct device *dev,
207 int min_alloc_order, int nid, const char *name);
208extern struct gen_pool *gen_pool_get(struct device *dev, const char *name);
209
210extern bool gen_pool_has_addr(struct gen_pool *pool, unsigned long start,
211 size_t size);
212
213#ifdef CONFIG_OF
214extern struct gen_pool *of_gen_pool_get(struct device_node *np,
215 const char *propname, int index);
216#else
217static inline struct gen_pool *of_gen_pool_get(struct device_node *np,
218 const char *propname, int index)
219{
220 return NULL;
221}
222#endif
223#endif /* __GENALLOC_H__ */