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
  37 struct device;
  38 struct device_node;
  39 struct 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  */
  50 typedef 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
  56 /*
  57  *  General purpose special memory pool descriptor.
  58  */
  59 struct 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  */
  73 struct 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         unsigned long start_addr;       /* start address of memory chunk */
  78         unsigned long end_addr;         /* end address of memory chunk (inclusive) */
  79         unsigned long bits[0];          /* bitmap for allocating memory chunk */
  80 };
  81
  82 /*
  83  *  gen_pool data descriptor for gen_pool_first_fit_align.
  84  */
  85 struct genpool_data_align {
  86         int align;              /* alignment by bytes for starting address */
  87 };
  88
  89 /*
  90  *  gen_pool data descriptor for gen_pool_fixed_alloc.
  91  */
  92 struct genpool_data_fixed {
  93         unsigned long offset;           /* The offset of the specific region */
  94 };
  95
  96 extern struct gen_pool *gen_pool_create(int, int);
  97 extern phys_addr_t gen_pool_virt_to_phys(struct gen_pool *pool, unsigned long);
  98 extern int gen_pool_add_virt(struct gen_pool *, unsigned long, phys_addr_t,
  99                              size_t, int);
 100 /**
 101  * gen_pool_add - add a new chunk of special memory to the pool
 102  * @pool: pool to add new memory chunk to
 103  * @addr: starting address of memory chunk to add to pool
 104  * @size: size in bytes of the memory chunk to add to pool
 105  * @nid: node id of the node the chunk structure and bitmap should be
 106  *       allocated on, or -1
 107  *
 108  * Add a new chunk of special memory to the specified pool.
 109  *
 110  * Returns 0 on success or a -ve errno on failure.
 111  */
 112 static inline int gen_pool_add(struct gen_pool *pool, unsigned long addr,
 113                                size_t size, int nid)
 114 {
 115         return gen_pool_add_virt(pool, addr, -1, size, nid);
 116 }
 117 extern void gen_pool_destroy(struct gen_pool *);
 118 extern unsigned long gen_pool_alloc(struct gen_pool *, size_t);
 119 extern unsigned long gen_pool_alloc_algo(struct gen_pool *, size_t,
 120                 genpool_algo_t algo, void *data);
 121 extern void *gen_pool_dma_alloc(struct gen_pool *pool, size_t size,
 122                 dma_addr_t *dma);
 123 extern void gen_pool_free(struct gen_pool *, unsigned long, size_t);
 124 extern void gen_pool_for_each_chunk(struct gen_pool *,
 125         void (*)(struct gen_pool *, struct gen_pool_chunk *, void *), void *);
 126 extern size_t gen_pool_avail(struct gen_pool *);
 127 extern size_t gen_pool_size(struct gen_pool *);
 128
 129 extern void gen_pool_set_algo(struct gen_pool *pool, genpool_algo_t algo,
 130                 void *data);
 131
 132 extern unsigned long gen_pool_first_fit(unsigned long *map, unsigned long size,
 133                 unsigned long start, unsigned int nr, void *data,
 134                 struct gen_pool *pool);
 135
 136 extern unsigned long gen_pool_fixed_alloc(unsigned long *map,
 137                 unsigned long size, unsigned long start, unsigned int nr,
 138                 void *data, struct gen_pool *pool);
 139
 140 extern unsigned long gen_pool_first_fit_align(unsigned long *map,
 141                 unsigned long size, unsigned long start, unsigned int nr,
 142                 void *data, struct gen_pool *pool);
 143
 144
 145 extern unsigned long gen_pool_first_fit_order_align(unsigned long *map,
 146                 unsigned long size, unsigned long start, unsigned int nr,
 147                 void *data, struct gen_pool *pool);
 148
 149 extern unsigned long gen_pool_best_fit(unsigned long *map, unsigned long size,
 150                 unsigned long start, unsigned int nr, void *data,
 151                 struct gen_pool *pool);
 152
 153
 154 extern struct gen_pool *devm_gen_pool_create(struct device *dev,
 155                 int min_alloc_order, int nid, const char *name);
 156 extern struct gen_pool *gen_pool_get(struct device *dev, const char *name);
 157
 158 bool addr_in_gen_pool(struct gen_pool *pool, unsigned long start,
 159                         size_t size);
 160
 161 #ifdef CONFIG_OF
 162 extern struct gen_pool *of_gen_pool_get(struct device_node *np,
 163         const char *propname, int index);
 164 #else
 165 static inline struct gen_pool *of_gen_pool_get(struct device_node *np,
 166         const char *propname, int index)
 167 {
 168         return NULL;
 169 }
 170 #endif
 171 #endif /* __GENALLOC_H__ */