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 36 struct device; 37 struct device_node; 38 struct gen_pool; 39 40 /** 41 * Allocation callback function type definition 42 * @map: Pointer to bitmap 43 * @size: The bitmap size in bits 44 * @start: The bitnumber to start searching at 45 * @nr: The number of zeroed bits we're looking for 46 * @data: optional additional data used by @genpool_algo_t 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 54 /* 55 * General purpose special memory pool descriptor. 56 */ 57 struct gen_pool { 58 spinlock_t lock; 59 struct list_head chunks; /* list of chunks in this pool */ 60 int min_alloc_order; /* minimum allocation order */ 61 62 genpool_algo_t algo; /* allocation function */ 63 void *data; 64 65 const char *name; 66 }; 67 68 /* 69 * General purpose special memory pool chunk descriptor. 70 */ 71 struct gen_pool_chunk { 72 struct list_head next_chunk; /* next chunk in pool */ 73 atomic_t avail; 74 phys_addr_t phys_addr; /* physical starting address of memory chunk */ 75 unsigned long start_addr; /* start address of memory chunk */ 76 unsigned long end_addr; /* end address of memory chunk (inclusive) */ 77 unsigned long bits[0]; /* bitmap for allocating memory chunk */ 78 }; 79 80 /* 81 * gen_pool data descriptor for gen_pool_first_fit_align. 82 */ 83 struct genpool_data_align { 84 int align; /* alignment by bytes for starting address */ 85 }; 86 87 extern struct gen_pool *gen_pool_create(int, int); 88 extern phys_addr_t gen_pool_virt_to_phys(struct gen_pool *pool, unsigned long); 89 extern int gen_pool_add_virt(struct gen_pool *, unsigned long, phys_addr_t, 90 size_t, int); 91 /** 92 * gen_pool_add - add a new chunk of special memory to the pool 93 * @pool: pool to add new memory chunk to 94 * @addr: starting address of memory chunk to add to pool 95 * @size: size in bytes of the memory chunk to add to pool 96 * @nid: node id of the node the chunk structure and bitmap should be 97 * allocated on, or -1 98 * 99 * Add a new chunk of special memory to the specified pool. 100 * 101 * Returns 0 on success or a -ve errno on failure. 102 */ 103 static inline int gen_pool_add(struct gen_pool *pool, unsigned long addr, 104 size_t size, int nid) 105 { 106 return gen_pool_add_virt(pool, addr, -1, size, nid); 107 } 108 extern void gen_pool_destroy(struct gen_pool *); 109 extern unsigned long gen_pool_alloc(struct gen_pool *, size_t); 110 extern unsigned long gen_pool_alloc_algo(struct gen_pool *, size_t, 111 genpool_algo_t algo, void *data); 112 extern void *gen_pool_dma_alloc(struct gen_pool *pool, size_t size, 113 dma_addr_t *dma); 114 extern void gen_pool_free(struct gen_pool *, unsigned long, size_t); 115 extern void gen_pool_for_each_chunk(struct gen_pool *, 116 void (*)(struct gen_pool *, struct gen_pool_chunk *, void *), void *); 117 extern size_t gen_pool_avail(struct gen_pool *); 118 extern size_t gen_pool_size(struct gen_pool *); 119 120 extern void gen_pool_set_algo(struct gen_pool *pool, genpool_algo_t algo, 121 void *data); 122 123 extern unsigned long gen_pool_first_fit(unsigned long *map, unsigned long size, 124 unsigned long start, unsigned int nr, void *data, 125 struct gen_pool *pool); 126 127 extern unsigned long gen_pool_first_fit_align(unsigned long *map, 128 unsigned long size, unsigned long start, unsigned int nr, 129 void *data, struct gen_pool *pool); 130 131 132 extern unsigned long gen_pool_first_fit_order_align(unsigned long *map, 133 unsigned long size, unsigned long start, unsigned int nr, 134 void *data, struct gen_pool *pool); 135 136 extern unsigned long gen_pool_best_fit(unsigned long *map, unsigned long size, 137 unsigned long start, unsigned int nr, void *data, 138 struct gen_pool *pool); 139 140 141 extern struct gen_pool *devm_gen_pool_create(struct device *dev, 142 int min_alloc_order, int nid, const char *name); 143 extern struct gen_pool *gen_pool_get(struct device *dev, const char *name); 144 145 bool addr_in_gen_pool(struct gen_pool *pool, unsigned long start, 146 size_t size); 147 148 #ifdef CONFIG_OF 149 extern struct gen_pool *of_gen_pool_get(struct device_node *np, 150 const char *propname, int index); 151 #else 152 static inline struct gen_pool *of_gen_pool_get(struct device_node *np, 153 const char *propname, int index) 154 { 155 return NULL; 156 } 157 #endif 158 #endif /* __GENALLOC_H__ */ 159