include/linux/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
  35 struct device;
  36 struct device_node;
  37 struct 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  */
  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                         unsigned long start_addr);
  54
  55 /*
  56  *  General purpose special memory pool descriptor.
  57  */
  58 struct gen_pool {
  59         spinlock_t lock;
  60         struct list_head chunks;        /* list of chunks in this pool */
  61         int min_alloc_order;            /* minimum allocation order */
  62
  63         genpool_algo_t algo;            /* allocation function */
  64         void *data;
  65
  66         const char *name;
  67 };
  68
  69 /*
  70  *  General purpose special memory pool chunk descriptor.
  71  */
  72 struct gen_pool_chunk {
  73         struct list_head next_chunk;    /* next chunk in pool */
  74         atomic_long_t avail;
  75         phys_addr_t phys_addr;          /* physical starting address of memory chunk */
  76         void *owner;                    /* private data to retrieve at alloc time */
  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_owner(struct gen_pool *, unsigned long, phys_addr_t,
  99                              size_t, int, void *);
 100
 101 static inline int gen_pool_add_virt(struct gen_pool *pool, unsigned long addr,
 102                 phys_addr_t phys, size_t size, int nid)
 103 {
 104         return gen_pool_add_owner(pool, addr, phys, size, nid, NULL);
 105 }
 106
 107 /**
 108  * gen_pool_add - add a new chunk of special memory to the pool
 109  * @pool: pool to add new memory chunk to
 110  * @addr: starting address of memory chunk to add to pool
 111  * @size: size in bytes of the memory chunk to add to pool
 112  * @nid: node id of the node the chunk structure and bitmap should be
 113  *       allocated on, or -1
 114  *
 115  * Add a new chunk of special memory to the specified pool.
 116  *
 117  * Returns 0 on success or a -ve errno on failure.
 118  */
 119 static inline int gen_pool_add(struct gen_pool *pool, unsigned long addr,
 120                                size_t size, int nid)
 121 {
 122         return gen_pool_add_virt(pool, addr, -1, size, nid);
 123 }
 124 extern void gen_pool_destroy(struct gen_pool *);
 125 unsigned long gen_pool_alloc_algo_owner(struct gen_pool *pool, size_t size,
 126                 genpool_algo_t algo, void *data, void **owner);
 127
 128 static inline unsigned long gen_pool_alloc_owner(struct gen_pool *pool,
 129                 size_t size, void **owner)
 130 {
 131         return gen_pool_alloc_algo_owner(pool, size, pool->algo, pool->data,
 132                         owner);
 133 }
 134
 135 static inline unsigned long gen_pool_alloc_algo(struct gen_pool *pool,
 136                 size_t size, genpool_algo_t algo, void *data)
 137 {
 138         return gen_pool_alloc_algo_owner(pool, size, algo, data, NULL);
 139 }
 140
 141 /**
 142  * gen_pool_alloc - allocate special memory from the pool
 143  * @pool: pool to allocate from
 144  * @size: number of bytes to allocate from the pool
 145  *
 146  * Allocate the requested number of bytes from the specified pool.
 147  * Uses the pool allocation function (with first-fit algorithm by default).
 148  * Can not be used in NMI handler on architectures without
 149  * NMI-safe cmpxchg implementation.
 150  */
 151 static inline unsigned long gen_pool_alloc(struct gen_pool *pool, size_t size)
 152 {
 153         return gen_pool_alloc_algo(pool, size, pool->algo, pool->data);
 154 }
 155
 156 extern void *gen_pool_dma_alloc(struct gen_pool *pool, size_t size,
 157                 dma_addr_t *dma);
 158 extern void *gen_pool_dma_alloc_algo(struct gen_pool *pool, size_t size,
 159                 dma_addr_t *dma, genpool_algo_t algo, void *data);
 160 extern void *gen_pool_dma_alloc_align(struct gen_pool *pool, size_t size,
 161                 dma_addr_t *dma, int align);
 162 extern void *gen_pool_dma_zalloc(struct gen_pool *pool, size_t size, dma_addr_t *dma);
 163 extern void *gen_pool_dma_zalloc_algo(struct gen_pool *pool, size_t size,
 164                 dma_addr_t *dma, genpool_algo_t algo, void *data);
 165 extern void *gen_pool_dma_zalloc_align(struct gen_pool *pool, size_t size,
 166                 dma_addr_t *dma, int align);
 167 extern void gen_pool_free_owner(struct gen_pool *pool, unsigned long addr,
 168                 size_t size, void **owner);
 169 static inline void gen_pool_free(struct gen_pool *pool, unsigned long addr,
 170                 size_t size)
 171 {
 172         gen_pool_free_owner(pool, addr, size, NULL);
 173 }
 174
 175 extern void gen_pool_for_each_chunk(struct gen_pool *,
 176         void (*)(struct gen_pool *, struct gen_pool_chunk *, void *), void *);
 177 extern size_t gen_pool_avail(struct gen_pool *);
 178 extern size_t gen_pool_size(struct gen_pool *);
 179
 180 extern void gen_pool_set_algo(struct gen_pool *pool, genpool_algo_t algo,
 181                 void *data);
 182
 183 extern unsigned long gen_pool_first_fit(unsigned long *map, unsigned long size,
 184                 unsigned long start, unsigned int nr, void *data,
 185                 struct gen_pool *pool, unsigned long start_addr);
 186
 187 extern unsigned long gen_pool_fixed_alloc(unsigned long *map,
 188                 unsigned long size, unsigned long start, unsigned int nr,
 189                 void *data, struct gen_pool *pool, unsigned long start_addr);
 190
 191 extern unsigned long gen_pool_first_fit_align(unsigned long *map,
 192                 unsigned long size, unsigned long start, unsigned int nr,
 193                 void *data, struct gen_pool *pool, unsigned long start_addr);
 194
 195
 196 extern unsigned long gen_pool_first_fit_order_align(unsigned long *map,
 197                 unsigned long size, unsigned long start, unsigned int nr,
 198                 void *data, struct gen_pool *pool, unsigned long start_addr);
 199
 200 extern unsigned long gen_pool_best_fit(unsigned long *map, unsigned long size,
 201                 unsigned long start, unsigned int nr, void *data,
 202                 struct gen_pool *pool, unsigned long start_addr);
 203
 204
 205 extern struct gen_pool *devm_gen_pool_create(struct device *dev,
 206                 int min_alloc_order, int nid, const char *name);
 207 extern struct gen_pool *gen_pool_get(struct device *dev, const char *name);
 208
 209 extern bool gen_pool_has_addr(struct gen_pool *pool, unsigned long start,
 210                         size_t size);
 211
 212 #ifdef CONFIG_OF
 213 extern struct gen_pool *of_gen_pool_get(struct device_node *np,
 214         const char *propname, int index);
 215 #else
 216 static inline struct gen_pool *of_gen_pool_get(struct device_node *np,
 217         const char *propname, int index)
 218 {
 219         return NULL;
 220 }
 221 #endif
 222 #endif /* __GENALLOC_H__ */