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_dma_alloc(struct gen_pool *pool, size_t size, 98 dma_addr_t *dma); 99 extern void gen_pool_free(struct gen_pool *, unsigned long, size_t); 100 extern void gen_pool_for_each_chunk(struct gen_pool *, 101 void (*)(struct gen_pool *, struct gen_pool_chunk *, void *), void *); 102 extern size_t gen_pool_avail(struct gen_pool *); 103 extern size_t gen_pool_size(struct gen_pool *); 104 105 extern void gen_pool_set_algo(struct gen_pool *pool, genpool_algo_t algo, 106 void *data); 107 108 extern unsigned long gen_pool_first_fit(unsigned long *map, unsigned long size, 109 unsigned long start, unsigned int nr, void *data); 110 111 extern unsigned long gen_pool_best_fit(unsigned long *map, unsigned long size, 112 unsigned long start, unsigned int nr, void *data); 113 114 extern struct gen_pool *devm_gen_pool_create(struct device *dev, 115 int min_alloc_order, int nid); 116 extern struct gen_pool *dev_get_gen_pool(struct device *dev); 117 118 #ifdef CONFIG_OF 119 extern struct gen_pool *of_get_named_gen_pool(struct device_node *np, 120 const char *propname, int index); 121 #else 122 static inline struct gen_pool *of_get_named_gen_pool(struct device_node *np, 123 const char *propname, int index) 124 { 125 return NULL; 126 } 127 #endif 128 #endif /* __GENALLOC_H__ */ 129