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, -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, pool->algo, 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, pool->algo, 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