1/*
2 * Basic general purpose allocator for managing special purpose
3 * memory, for example, memory that is not managed by the regular
4 * kmalloc/kfree interface.  Uses for this includes on-device special
5 * memory, uncached memory etc.
6 *
7 * It is safe to use the allocator in NMI handlers and other special
8 * unblockable contexts that could otherwise deadlock on locks.  This
9 * is implemented by using atomic operations and retries on any
10 * conflicts.  The disadvantage is that there may be livelocks in
11 * extreme cases.  For better scalability, one allocator can be used
12 * for each CPU.
13 *
14 * The lockless operation only works if there is enough memory
15 * available.  If new memory is added to the pool a lock has to be
16 * still taken.  So any user relying on locklessness has to ensure
17 * that sufficient memory is preallocated.
18 *
19 * The basic atomic operation of this allocator is cmpxchg on long.
20 * On architectures that don't have NMI-safe cmpxchg implementation,
21 * the allocator can NOT be used in NMI handler.  So code uses the
22 * allocator in NMI handler should depend on
23 * CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG.
24 *
25 * This source code is licensed under the GNU General Public License,
26 * Version 2.  See the file COPYING for more details.
27 */
28
29
30#ifndef __GENALLOC_H__
31#define __GENALLOC_H__
32
33#include <linux/spinlock_types.h>
34
35struct device;
36struct device_node;
37
38/**
39 * Allocation callback function type definition
40 * @map: Pointer to bitmap
41 * @size: The bitmap size in bits
42 * @start: The bitnumber to start searching at
43 * @nr: The number of zeroed bits we're looking for
44 * @data: optional additional data used by @genpool_algo_t
45 */
46typedef unsigned long (*genpool_algo_t)(unsigned long *map,
47			unsigned long size,
48			unsigned long start,
49			unsigned int nr,
50			void *data);
51
52/*
53 *  General purpose special memory pool descriptor.
54 */
55struct gen_pool {
56	spinlock_t lock;
57	struct list_head chunks;	/* list of chunks in this pool */
58	int min_alloc_order;		/* minimum allocation order */
59
60	genpool_algo_t algo;		/* allocation function */
61	void *data;
62
63	const char *name;
64};
65
66/*
67 *  General purpose special memory pool chunk descriptor.
68 */
69struct gen_pool_chunk {
70	struct list_head next_chunk;	/* next chunk in pool */
71	atomic_t avail;
72	phys_addr_t phys_addr;		/* physical starting address of memory chunk */
73	unsigned long start_addr;	/* start address of memory chunk */
74	unsigned long end_addr;		/* end address of memory chunk (inclusive) */
75	unsigned long bits[0];		/* bitmap for allocating memory chunk */
76};
77
78extern struct gen_pool *gen_pool_create(int, int);
79extern phys_addr_t gen_pool_virt_to_phys(struct gen_pool *pool, unsigned long);
80extern int gen_pool_add_virt(struct gen_pool *, unsigned long, phys_addr_t,
81			     size_t, int);
82/**
83 * gen_pool_add - add a new chunk of special memory to the pool
84 * @pool: pool to add new memory chunk to
85 * @addr: starting address of memory chunk to add to pool
86 * @size: size in bytes of the memory chunk to add to pool
87 * @nid: node id of the node the chunk structure and bitmap should be
88 *       allocated on, or -1
89 *
90 * Add a new chunk of special memory to the specified pool.
91 *
92 * Returns 0 on success or a -ve errno on failure.
93 */
94static inline int gen_pool_add(struct gen_pool *pool, unsigned long addr,
95			       size_t size, int nid)
96{
97	return gen_pool_add_virt(pool, addr, -1, size, nid);
98}
99extern void gen_pool_destroy(struct gen_pool *);
100extern unsigned long gen_pool_alloc(struct gen_pool *, size_t);
101extern void *gen_pool_dma_alloc(struct gen_pool *pool, size_t size,
102		dma_addr_t *dma);
103extern void gen_pool_free(struct gen_pool *, unsigned long, size_t);
104extern void gen_pool_for_each_chunk(struct gen_pool *,
105	void (*)(struct gen_pool *, struct gen_pool_chunk *, void *), void *);
106extern size_t gen_pool_avail(struct gen_pool *);
107extern size_t gen_pool_size(struct gen_pool *);
108
109extern void gen_pool_set_algo(struct gen_pool *pool, genpool_algo_t algo,
110		void *data);
111
112extern unsigned long gen_pool_first_fit(unsigned long *map, unsigned long size,
113		unsigned long start, unsigned int nr, void *data);
114
115extern unsigned long gen_pool_first_fit_order_align(unsigned long *map,
116		unsigned long size, unsigned long start, unsigned int nr,
117		void *data);
118
119extern unsigned long gen_pool_best_fit(unsigned long *map, unsigned long size,
120		unsigned long start, unsigned int nr, void *data);
121
122extern struct gen_pool *devm_gen_pool_create(struct device *dev,
123		int min_alloc_order, int nid, const char *name);
124extern struct gen_pool *gen_pool_get(struct device *dev, const char *name);
125
126bool addr_in_gen_pool(struct gen_pool *pool, unsigned long start,
127			size_t size);
128
129#ifdef CONFIG_OF
130extern struct gen_pool *of_gen_pool_get(struct device_node *np,
131	const char *propname, int index);
132#else
133static inline struct gen_pool *of_gen_pool_get(struct device_node *np,
134	const char *propname, int index)
135{
136	return NULL;
137}
138#endif
139#endif /* __GENALLOC_H__ */
140