LXR linux/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
  35struct device;
  36struct device_node;
  37struct 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 */
  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                        unsigned long start_addr);
  54
  55/*
  56 *  General purpose special memory pool descriptor.
  57 */
  58struct 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 */
  72struct 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[];           /* bitmap for allocating memory chunk */
  80};
  81
  82/*
  83 *  gen_pool data descriptor for gen_pool_first_fit_align.
  84 */
  85struct 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 */
  92struct genpool_data_fixed {
  93        unsigned long offset;           /* The offset of the specific region */
  94};
  95
  96extern struct gen_pool *gen_pool_create(int, int);
  97extern phys_addr_t gen_pool_virt_to_phys(struct gen_pool *pool, unsigned long);
  98extern int gen_pool_add_owner(struct gen_pool *, unsigned long, phys_addr_t,
  99                             size_t, int, void *);
 100
 101static 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 */
 119static 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}
 124extern void gen_pool_destroy(struct gen_pool *);
 125unsigned long gen_pool_alloc_algo_owner(struct gen_pool *pool, size_t size,
 126                genpool_algo_t algo, void *data, void **owner);
 127
 128static 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
 135static 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 */
 151static 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
 156extern void *gen_pool_dma_alloc(struct gen_pool *pool, size_t size,
 157                dma_addr_t *dma);
 158extern void *gen_pool_dma_alloc_algo(struct gen_pool *pool, size_t size,
 159                dma_addr_t *dma, genpool_algo_t algo, void *data);
 160extern void *gen_pool_dma_alloc_align(struct gen_pool *pool, size_t size,
 161                dma_addr_t *dma, int align);
 162extern void *gen_pool_dma_zalloc(struct gen_pool *pool, size_t size, dma_addr_t *dma);
 163extern void *gen_pool_dma_zalloc_algo(struct gen_pool *pool, size_t size,
 164                dma_addr_t *dma, genpool_algo_t algo, void *data);
 165extern void *gen_pool_dma_zalloc_align(struct gen_pool *pool, size_t size,
 166                dma_addr_t *dma, int align);
 167extern void gen_pool_free_owner(struct gen_pool *pool, unsigned long addr,
 168                size_t size, void **owner);
 169static 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
 175extern void gen_pool_for_each_chunk(struct gen_pool *,
 176        void (*)(struct gen_pool *, struct gen_pool_chunk *, void *), void *);
 177extern size_t gen_pool_avail(struct gen_pool *);
 178extern size_t gen_pool_size(struct gen_pool *);
 179
 180extern void gen_pool_set_algo(struct gen_pool *pool, genpool_algo_t algo,
 181                void *data);
 182
 183extern 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
 187extern 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
 191extern 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
 196extern 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
 200extern 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
 205extern struct gen_pool *devm_gen_pool_create(struct device *dev,
 206                int min_alloc_order, int nid, const char *name);
 207extern struct gen_pool *gen_pool_get(struct device *dev, const char *name);
 208
 209extern bool gen_pool_has_addr(struct gen_pool *pool, unsigned long start,
 210                        size_t size);
 211
 212#ifdef CONFIG_OF
 213extern struct gen_pool *of_gen_pool_get(struct device_node *np,
 214        const char *propname, int index);
 215#else
 216static 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__ */
 223