LXR linux/include/linux/genalloc.h

   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/types.h>
  34#include <linux/spinlock_types.h>
  35#include <linux/atomic.h>
  36
  37struct device;
  38struct device_node;
  39struct gen_pool;
  40
  41/**
  42 * typedef genpool_algo_t: Allocation callback function type definition
  43 * @map: Pointer to bitmap
  44 * @size: The bitmap size in bits
  45 * @start: The bitnumber to start searching at
  46 * @nr: The number of zeroed bits we're looking for
  47 * @data: optional additional data used by the callback
  48 * @pool: the pool being allocated from
  49 */
  50typedef unsigned long (*genpool_algo_t)(unsigned long *map,
  51                        unsigned long size,
  52                        unsigned long start,
  53                        unsigned int nr,
  54                        void *data, struct gen_pool *pool,
  55                        unsigned long start_addr);
  56
  57/*
  58 *  General purpose special memory pool descriptor.
  59 */
  60struct gen_pool {
  61        spinlock_t lock;
  62        struct list_head chunks;        /* list of chunks in this pool */
  63        int min_alloc_order;            /* minimum allocation order */
  64
  65        genpool_algo_t algo;            /* allocation function */
  66        void *data;
  67
  68        const char *name;
  69};
  70
  71/*
  72 *  General purpose special memory pool chunk descriptor.
  73 */
  74struct gen_pool_chunk {
  75        struct list_head next_chunk;    /* next chunk in pool */
  76        atomic_long_t avail;
  77        phys_addr_t phys_addr;          /* physical starting address of memory chunk */
  78        void *owner;                    /* private data to retrieve at alloc time */
  79        unsigned long start_addr;       /* start address of memory chunk */
  80        unsigned long end_addr;         /* end address of memory chunk (inclusive) */
  81        unsigned long bits[0];          /* bitmap for allocating memory chunk */
  82};
  83
  84/*
  85 *  gen_pool data descriptor for gen_pool_first_fit_align.
  86 */
  87struct genpool_data_align {
  88        int align;              /* alignment by bytes for starting address */
  89};
  90
  91/*
  92 *  gen_pool data descriptor for gen_pool_fixed_alloc.
  93 */
  94struct genpool_data_fixed {
  95        unsigned long offset;           /* The offset of the specific region */
  96};
  97
  98extern struct gen_pool *gen_pool_create(int, int);
  99extern phys_addr_t gen_pool_virt_to_phys(struct gen_pool *pool, unsigned long);
 100extern int gen_pool_add_owner(struct gen_pool *, unsigned long, phys_addr_t,
 101                             size_t, int, void *);
 102
 103static inline int gen_pool_add_virt(struct gen_pool *pool, unsigned long addr,
 104                phys_addr_t phys, size_t size, int nid)
 105{
 106        return gen_pool_add_owner(pool, addr, phys, size, nid, NULL);
 107}
 108
 109/**
 110 * gen_pool_add - add a new chunk of special memory to the pool
 111 * @pool: pool to add new memory chunk to
 112 * @addr: starting address of memory chunk to add to pool
 113 * @size: size in bytes of the memory chunk to add to pool
 114 * @nid: node id of the node the chunk structure and bitmap should be
 115 *       allocated on, or -1
 116 *
 117 * Add a new chunk of special memory to the specified pool.
 118 *
 119 * Returns 0 on success or a -ve errno on failure.
 120 */
 121static inline int gen_pool_add(struct gen_pool *pool, unsigned long addr,
 122                               size_t size, int nid)
 123{
 124        return gen_pool_add_virt(pool, addr, -1, size, nid);
 125}
 126extern void gen_pool_destroy(struct gen_pool *);
 127unsigned long gen_pool_alloc_algo_owner(struct gen_pool *pool, size_t size,
 128                genpool_algo_t algo, void *data, void **owner);
 129
 130static inline unsigned long gen_pool_alloc_owner(struct gen_pool *pool,
 131                size_t size, void **owner)
 132{
 133        return gen_pool_alloc_algo_owner(pool, size, pool->algo, pool->data,
 134                        owner);
 135}
 136
 137static inline unsigned long gen_pool_alloc_algo(struct gen_pool *pool,
 138                size_t size, genpool_algo_t algo, void *data)
 139{
 140        return gen_pool_alloc_algo_owner(pool, size, algo, data, NULL);
 141}
 142
 143/**
 144 * gen_pool_alloc - allocate special memory from the pool
 145 * @pool: pool to allocate from
 146 * @size: number of bytes to allocate from the pool
 147 *
 148 * Allocate the requested number of bytes from the specified pool.
 149 * Uses the pool allocation function (with first-fit algorithm by default).
 150 * Can not be used in NMI handler on architectures without
 151 * NMI-safe cmpxchg implementation.
 152 */
 153static inline unsigned long gen_pool_alloc(struct gen_pool *pool, size_t size)
 154{
 155        return gen_pool_alloc_algo(pool, size, pool->algo, pool->data);
 156}
 157
 158extern void *gen_pool_dma_alloc(struct gen_pool *pool, size_t size,
 159                dma_addr_t *dma);
 160extern void *gen_pool_dma_alloc_algo(struct gen_pool *pool, size_t size,
 161                dma_addr_t *dma, genpool_algo_t algo, void *data);
 162extern void *gen_pool_dma_alloc_align(struct gen_pool *pool, size_t size,
 163                dma_addr_t *dma, int align);
 164extern void *gen_pool_dma_zalloc(struct gen_pool *pool, size_t size, dma_addr_t *dma);
 165extern void *gen_pool_dma_zalloc_algo(struct gen_pool *pool, size_t size,
 166                dma_addr_t *dma, genpool_algo_t algo, void *data);
 167extern void *gen_pool_dma_zalloc_align(struct gen_pool *pool, size_t size,
 168                dma_addr_t *dma, int align);
 169extern void gen_pool_free_owner(struct gen_pool *pool, unsigned long addr,
 170                size_t size, void **owner);
 171static inline void gen_pool_free(struct gen_pool *pool, unsigned long addr,
 172                size_t size)
 173{
 174        gen_pool_free_owner(pool, addr, size, NULL);
 175}
 176
 177extern void gen_pool_for_each_chunk(struct gen_pool *,
 178        void (*)(struct gen_pool *, struct gen_pool_chunk *, void *), void *);
 179extern size_t gen_pool_avail(struct gen_pool *);
 180extern size_t gen_pool_size(struct gen_pool *);
 181
 182extern void gen_pool_set_algo(struct gen_pool *pool, genpool_algo_t algo,
 183                void *data);
 184
 185extern unsigned long gen_pool_first_fit(unsigned long *map, unsigned long size,
 186                unsigned long start, unsigned int nr, void *data,
 187                struct gen_pool *pool, unsigned long start_addr);
 188
 189extern unsigned long gen_pool_fixed_alloc(unsigned long *map,
 190                unsigned long size, unsigned long start, unsigned int nr,
 191                void *data, struct gen_pool *pool, unsigned long start_addr);
 192
 193extern unsigned long gen_pool_first_fit_align(unsigned long *map,
 194                unsigned long size, unsigned long start, unsigned int nr,
 195                void *data, struct gen_pool *pool, unsigned long start_addr);
 196
 197
 198extern unsigned long gen_pool_first_fit_order_align(unsigned long *map,
 199                unsigned long size, unsigned long start, unsigned int nr,
 200                void *data, struct gen_pool *pool, unsigned long start_addr);
 201
 202extern unsigned long gen_pool_best_fit(unsigned long *map, unsigned long size,
 203                unsigned long start, unsigned int nr, void *data,
 204                struct gen_pool *pool, unsigned long start_addr);
 205
 206
 207extern struct gen_pool *devm_gen_pool_create(struct device *dev,
 208                int min_alloc_order, int nid, const char *name);
 209extern struct gen_pool *gen_pool_get(struct device *dev, const char *name);
 210
 211extern bool gen_pool_has_addr(struct gen_pool *pool, unsigned long start,
 212                        size_t size);
 213
 214#ifdef CONFIG_OF
 215extern struct gen_pool *of_gen_pool_get(struct device_node *np,
 216        const char *propname, int index);
 217#else
 218static inline struct gen_pool *of_gen_pool_get(struct device_node *np,
 219        const char *propname, int index)
 220{
 221        return NULL;
 222}
 223#endif
 224#endif /* __GENALLOC_H__ */
 225