| 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 | struct device; |
| 34 | struct device_node; |
| 35 | |
| 36 | /** |
| 37 | * Allocation callback function type definition |
| 38 | * @map: Pointer to bitmap |
| 39 | * @size: The bitmap size in bits |
| 40 | * @start: The bitnumber to start searching at |
| 41 | * @nr: The number of zeroed bits we're looking for |
| 42 | * @data: optional additional data used by @genpool_algo_t |
| 43 | */ |
| 44 | typedef unsigned long (*genpool_algo_t)(unsigned long *map, |
| 45 | unsigned long size, |
| 46 | unsigned long start, |
| 47 | unsigned int nr, |
| 48 | void *data); |
| 49 | |
| 50 | /* |
| 51 | * General purpose special memory pool descriptor. |
| 52 | */ |
| 53 | struct gen_pool { |
| 54 | spinlock_t lock; |
| 55 | struct list_head chunks; /* list of chunks in this pool */ |
| 56 | int min_alloc_order; /* minimum allocation order */ |
| 57 | |
| 58 | genpool_algo_t algo; /* allocation function */ |
| 59 | void *data; |
| 60 | }; |
| 61 | |
| 62 | /* |
| 63 | * General purpose special memory pool chunk descriptor. |
| 64 | */ |
| 65 | struct gen_pool_chunk { |
| 66 | struct list_head next_chunk; /* next chunk in pool */ |
| 67 | atomic_t avail; |
| 68 | phys_addr_t phys_addr; /* physical starting address of memory chunk */ |
| 69 | unsigned long start_addr; /* start address of memory chunk */ |
| 70 | unsigned long end_addr; /* end address of memory chunk (inclusive) */ |
| 71 | unsigned long bits[0]; /* bitmap for allocating memory chunk */ |
| 72 | }; |
| 73 | |
| 74 | extern struct gen_pool *gen_pool_create(int, int); |
| 75 | extern phys_addr_t gen_pool_virt_to_phys(struct gen_pool *pool, unsigned long); |
| 76 | extern int gen_pool_add_virt(struct gen_pool *, unsigned long, phys_addr_t, |
| 77 | size_t, int); |
| 78 | /** |
| 79 | * gen_pool_add - add a new chunk of special memory to the pool |
| 80 | * @pool: pool to add new memory chunk to |
| 81 | * @addr: starting address of memory chunk to add to pool |
| 82 | * @size: size in bytes of the memory chunk to add to pool |
| 83 | * @nid: node id of the node the chunk structure and bitmap should be |
| 84 | * allocated on, or -1 |
| 85 | * |
| 86 | * Add a new chunk of special memory to the specified pool. |
| 87 | * |
| 88 | * Returns 0 on success or a -ve errno on failure. |
| 89 | */ |
| 90 | static inline int gen_pool_add(struct gen_pool *pool, unsigned long addr, |
| 91 | size_t size, int nid) |
| 92 | { |
| 93 | return gen_pool_add_virt(pool, addr, -1, size, nid); |
| 94 | } |
| 95 | extern void gen_pool_destroy(struct gen_pool *); |
| 96 | extern unsigned long gen_pool_alloc(struct gen_pool *, size_t); |
| 97 | extern void gen_pool_free(struct gen_pool *, unsigned long, size_t); |
| 98 | extern void gen_pool_for_each_chunk(struct gen_pool *, |
| 99 | void (*)(struct gen_pool *, struct gen_pool_chunk *, void *), void *); |
| 100 | extern size_t gen_pool_avail(struct gen_pool *); |
| 101 | extern size_t gen_pool_size(struct gen_pool *); |
| 102 | |
| 103 | extern void gen_pool_set_algo(struct gen_pool *pool, genpool_algo_t algo, |
| 104 | void *data); |
| 105 | |
| 106 | extern unsigned long gen_pool_first_fit(unsigned long *map, unsigned long size, |
| 107 | unsigned long start, unsigned int nr, void *data); |
| 108 | |
| 109 | extern unsigned long gen_pool_best_fit(unsigned long *map, unsigned long size, |
| 110 | unsigned long start, unsigned int nr, void *data); |
| 111 | |
| 112 | extern struct gen_pool *devm_gen_pool_create(struct device *dev, |
| 113 | int min_alloc_order, int nid); |
| 114 | extern struct gen_pool *dev_get_gen_pool(struct device *dev); |
| 115 | |
| 116 | #ifdef CONFIG_OF |
| 117 | extern struct gen_pool *of_get_named_gen_pool(struct device_node *np, |
| 118 | const char *propname, int index); |
| 119 | #else |
| 120 | static inline struct gen_pool *of_get_named_gen_pool(struct device_node *np, |
| 121 | const char *propname, int index) |
| 122 | { |
| 123 | return NULL; |
| 124 | } |
| 125 | #endif |
| 126 | #endif /* __GENALLOC_H__ */ |