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
  36struct device;
  37struct device_node;
  38struct gen_pool;
  39
  40/**
  41 * Allocation callback function type definition
  42 * @map: Pointer to bitmap
  43 * @size: The bitmap size in bits
  44 * @start: The bitnumber to start searching at
  45 * @nr: The number of zeroed bits we're looking for
  46 * @data: optional additional data used by @genpool_algo_t
  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
  54/*
  55 *  General purpose special memory pool descriptor.
  56 */
  57struct gen_pool {
  58        spinlock_t lock;
  59        struct list_head chunks;        /* list of chunks in this pool */
  60        int min_alloc_order;            /* minimum allocation order */
  61
  62        genpool_algo_t algo;            /* allocation function */
  63        void *data;
  64
  65        const char *name;
  66};
  67
  68/*
  69 *  General purpose special memory pool chunk descriptor.
  70 */
  71struct gen_pool_chunk {
  72        struct list_head next_chunk;    /* next chunk in pool */
  73        atomic_t avail;
  74        phys_addr_t phys_addr;          /* physical starting address of memory chunk */
  75        unsigned long start_addr;       /* start address of memory chunk */
  76        unsigned long end_addr;         /* end address of memory chunk (inclusive) */
  77        unsigned long bits[0];          /* bitmap for allocating memory chunk */
  78};
  79
  80/*
  81 *  gen_pool data descriptor for gen_pool_first_fit_align.
  82 */
  83struct genpool_data_align {
  84        int align;              /* alignment by bytes for starting address */
  85};
  86
  87/*
  88 *  gen_pool data descriptor for gen_pool_fixed_alloc.
  89 */
  90struct genpool_data_fixed {
  91        unsigned long offset;           /* The offset of the specific region */
  92};
  93
  94extern struct gen_pool *gen_pool_create(int, int);
  95extern phys_addr_t gen_pool_virt_to_phys(struct gen_pool *pool, unsigned long);
  96extern int gen_pool_add_virt(struct gen_pool *, unsigned long, phys_addr_t,
  97                             size_t, int);
  98/**
  99 * gen_pool_add - add a new chunk of special memory to the pool
 100 * @pool: pool to add new memory chunk to
 101 * @addr: starting address of memory chunk to add to pool
 102 * @size: size in bytes of the memory chunk to add to pool
 103 * @nid: node id of the node the chunk structure and bitmap should be
 104 *       allocated on, or -1
 105 *
 106 * Add a new chunk of special memory to the specified pool.
 107 *
 108 * Returns 0 on success or a -ve errno on failure.
 109 */
 110static inline int gen_pool_add(struct gen_pool *pool, unsigned long addr,
 111                               size_t size, int nid)
 112{
 113        return gen_pool_add_virt(pool, addr, -1, size, nid);
 114}
 115extern void gen_pool_destroy(struct gen_pool *);
 116extern unsigned long gen_pool_alloc(struct gen_pool *, size_t);
 117extern unsigned long gen_pool_alloc_algo(struct gen_pool *, size_t,
 118                genpool_algo_t algo, void *data);
 119extern void *gen_pool_dma_alloc(struct gen_pool *pool, size_t size,
 120                dma_addr_t *dma);
 121extern void gen_pool_free(struct gen_pool *, unsigned long, size_t);
 122extern void gen_pool_for_each_chunk(struct gen_pool *,
 123        void (*)(struct gen_pool *, struct gen_pool_chunk *, void *), void *);
 124extern size_t gen_pool_avail(struct gen_pool *);
 125extern size_t gen_pool_size(struct gen_pool *);
 126
 127extern void gen_pool_set_algo(struct gen_pool *pool, genpool_algo_t algo,
 128                void *data);
 129
 130extern unsigned long gen_pool_first_fit(unsigned long *map, unsigned long size,
 131                unsigned long start, unsigned int nr, void *data,
 132                struct gen_pool *pool);
 133
 134extern unsigned long gen_pool_fixed_alloc(unsigned long *map,
 135                unsigned long size, unsigned long start, unsigned int nr,
 136                void *data, struct gen_pool *pool);
 137
 138extern unsigned long gen_pool_first_fit_align(unsigned long *map,
 139                unsigned long size, unsigned long start, unsigned int nr,
 140                void *data, struct gen_pool *pool);
 141
 142
 143extern unsigned long gen_pool_first_fit_order_align(unsigned long *map,
 144                unsigned long size, unsigned long start, unsigned int nr,
 145                void *data, struct gen_pool *pool);
 146
 147extern unsigned long gen_pool_best_fit(unsigned long *map, unsigned long size,
 148                unsigned long start, unsigned int nr, void *data,
 149                struct gen_pool *pool);
 150
 151
 152extern struct gen_pool *devm_gen_pool_create(struct device *dev,
 153                int min_alloc_order, int nid, const char *name);
 154extern struct gen_pool *gen_pool_get(struct device *dev, const char *name);
 155
 156bool addr_in_gen_pool(struct gen_pool *pool, unsigned long start,
 157                        size_t size);
 158
 159#ifdef CONFIG_OF
 160extern struct gen_pool *of_gen_pool_get(struct device_node *np,
 161        const char *propname, int index);
 162#else
 163static inline struct gen_pool *of_gen_pool_get(struct device_node *np,
 164        const char *propname, int index)
 165{
 166        return NULL;
 167}
 168#endif
 169#endif /* __GENALLOC_H__ */
 170