genalloc.h

  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__ */