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 */
48typedef 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 */
58struct 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 */
72struct 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 */
85struct 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 */
92struct genpool_data_fixed {
93 unsigned long offset; /* The offset of the specific region */
94};
95
96extern struct gen_pool *gen_pool_create(int, int);
97extern phys_addr_t gen_pool_virt_to_phys(struct gen_pool *pool, unsigned long);
98extern int gen_pool_add_owner(struct gen_pool *, unsigned long, phys_addr_t,
99 size_t, int, void *);
100
101static 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 */
119static 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, phys: -1, size, nid);
123}
124extern void gen_pool_destroy(struct gen_pool *);
125unsigned long gen_pool_alloc_algo_owner(struct gen_pool *pool, size_t size,
126 genpool_algo_t algo, void *data, void **owner);
127
128static 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, algo: pool->algo, data: pool->data,
132 owner);
133}
134
135static 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 */
151static inline unsigned long gen_pool_alloc(struct gen_pool *pool, size_t size)
152{
153 return gen_pool_alloc_algo(pool, size, algo: pool->algo, data: pool->data);
154}
155
156extern void *gen_pool_dma_alloc(struct gen_pool *pool, size_t size,
157 dma_addr_t *dma);
158extern void *gen_pool_dma_alloc_algo(struct gen_pool *pool, size_t size,
159 dma_addr_t *dma, genpool_algo_t algo, void *data);
160extern void *gen_pool_dma_alloc_align(struct gen_pool *pool, size_t size,
161 dma_addr_t *dma, int align);
162extern void *gen_pool_dma_zalloc(struct gen_pool *pool, size_t size, dma_addr_t *dma);
163extern void *gen_pool_dma_zalloc_algo(struct gen_pool *pool, size_t size,
164 dma_addr_t *dma, genpool_algo_t algo, void *data);
165extern void *gen_pool_dma_zalloc_align(struct gen_pool *pool, size_t size,
166 dma_addr_t *dma, int align);
167extern void gen_pool_free_owner(struct gen_pool *pool, unsigned long addr,
168 size_t size, void **owner);
169static 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
175extern void gen_pool_for_each_chunk(struct gen_pool *,
176 void (*)(struct gen_pool *, struct gen_pool_chunk *, void *), void *);
177extern size_t gen_pool_avail(struct gen_pool *);
178extern size_t gen_pool_size(struct gen_pool *);
179
180extern void gen_pool_set_algo(struct gen_pool *pool, genpool_algo_t algo,
181 void *data);
182
183extern 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
187extern 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
191extern 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
196extern 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
200extern 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
205extern struct gen_pool *devm_gen_pool_create(struct device *dev,
206 int min_alloc_order, int nid, const char *name);
207extern struct gen_pool *gen_pool_get(struct device *dev, const char *name);
208
209extern bool gen_pool_has_addr(struct gen_pool *pool, unsigned long start,
210 size_t size);
211
212#ifdef CONFIG_OF
213extern struct gen_pool *of_gen_pool_get(struct device_node *np,
214 const char *propname, int index);
215#else
216static 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