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
  36 struct device;
  37 struct device_node;
  38 struct 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  */
  48 typedef 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  */
  57 struct 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  */
  71 struct 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  */
  83 struct 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  */
  90 struct genpool_data_fixed {
  91         unsigned long offset;           /* The offset of the specific region */
  92 };
  93
  94 extern struct gen_pool *gen_pool_create(int, int);
  95 extern phys_addr_t gen_pool_virt_to_phys(struct gen_pool *pool, unsigned long);
  96 extern 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  */
 110 static 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 }
 115 extern void gen_pool_destroy(struct gen_pool *);
 116 extern unsigned long gen_pool_alloc(struct gen_pool *, size_t);
 117 extern unsigned long gen_pool_alloc_algo(struct gen_pool *, size_t,
 118                 genpool_algo_t algo, void *data);
 119 extern void *gen_pool_dma_alloc(struct gen_pool *pool, size_t size,
 120                 dma_addr_t *dma);
 121 extern void gen_pool_free(struct gen_pool *, unsigned long, size_t);
 122 extern void gen_pool_for_each_chunk(struct gen_pool *,
 123         void (*)(struct gen_pool *, struct gen_pool_chunk *, void *), void *);
 124 extern size_t gen_pool_avail(struct gen_pool *);
 125 extern size_t gen_pool_size(struct gen_pool *);
 126
 127 extern void gen_pool_set_algo(struct gen_pool *pool, genpool_algo_t algo,
 128                 void *data);
 129
 130 extern 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
 134 extern 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
 138 extern 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
 143 extern 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
 147 extern 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
 152 extern struct gen_pool *devm_gen_pool_create(struct device *dev,
 153                 int min_alloc_order, int nid, const char *name);
 154 extern struct gen_pool *gen_pool_get(struct device *dev, const char *name);
 155
 156 bool addr_in_gen_pool(struct gen_pool *pool, unsigned long start,
 157                         size_t size);
 158
 159 #ifdef CONFIG_OF
 160 extern struct gen_pool *of_gen_pool_get(struct device_node *np,
 161         const char *propname, int index);
 162 #else
 163 static 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__ */