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 #include <linux/atomic.h> 36 37 struct device; 38 struct device_node; 39 struct gen_pool; 40 41 /** 42 * typedef genpool_algo_t: Allocation callback function type definition 43 * @map: Pointer to bitmap 44 * @size: The bitmap size in bits 45 * @start: The bitnumber to start searching at 46 * @nr: The number of zeroed bits we're looking for 47 * @data: optional additional data used by the callback 48 * @pool: the pool being allocated from 49 */ 50 typedef unsigned long (*genpool_algo_t)(unsigned long *map, 51 unsigned long size, 52 unsigned long start, 53 unsigned int nr, 54 void *data, struct gen_pool *pool, 55 unsigned long start_addr); 56 57 /* 58 * General purpose special memory pool descriptor. 59 */ 60 struct gen_pool { 61 spinlock_t lock; 62 struct list_head chunks; /* list of chunks in this pool */ 63 int min_alloc_order; /* minimum allocation order */ 64 65 genpool_algo_t algo; /* allocation function */ 66 void *data; 67 68 const char *name; 69 }; 70 71 /* 72 * General purpose special memory pool chunk descriptor. 73 */ 74 struct gen_pool_chunk { 75 struct list_head next_chunk; /* next chunk in pool */ 76 atomic_long_t avail; 77 phys_addr_t phys_addr; /* physical starting address of memory chunk */ 78 void *owner; /* private data to retrieve at alloc time */ 79 unsigned long start_addr; /* start address of memory chunk */ 80 unsigned long end_addr; /* end address of memory chunk (inclusive) */ 81 unsigned long bits[0]; /* bitmap for allocating memory chunk */ 82 }; 83 84 /* 85 * gen_pool data descriptor for gen_pool_first_fit_align. 86 */ 87 struct genpool_data_align { 88 int align; /* alignment by bytes for starting address */ 89 }; 90 91 /* 92 * gen_pool data descriptor for gen_pool_fixed_alloc. 93 */ 94 struct genpool_data_fixed { 95 unsigned long offset; /* The offset of the specific region */ 96 }; 97 98 extern struct gen_pool *gen_pool_create(int, int); 99 extern phys_addr_t gen_pool_virt_to_phys(struct gen_pool *pool, unsigned long); 100 extern int gen_pool_add_owner(struct gen_pool *, unsigned long, phys_addr_t, 101 size_t, int, void *); 102 103 static inline int gen_pool_add_virt(struct gen_pool *pool, unsigned long addr, 104 phys_addr_t phys, size_t size, int nid) 105 { 106 return gen_pool_add_owner(pool, addr, phys, size, nid, NULL); 107 } 108 109 /** 110 * gen_pool_add - add a new chunk of special memory to the pool 111 * @pool: pool to add new memory chunk to 112 * @addr: starting address of memory chunk to add to pool 113 * @size: size in bytes of the memory chunk to add to pool 114 * @nid: node id of the node the chunk structure and bitmap should be 115 * allocated on, or -1 116 * 117 * Add a new chunk of special memory to the specified pool. 118 * 119 * Returns 0 on success or a -ve errno on failure. 120 */ 121 static inline int gen_pool_add(struct gen_pool *pool, unsigned long addr, 122 size_t size, int nid) 123 { 124 return gen_pool_add_virt(pool, addr, -1, size, nid); 125 } 126 extern void gen_pool_destroy(struct gen_pool *); 127 unsigned long gen_pool_alloc_algo_owner(struct gen_pool *pool, size_t size, 128 genpool_algo_t algo, void *data, void **owner); 129 130 static inline unsigned long gen_pool_alloc_owner(struct gen_pool *pool, 131 size_t size, void **owner) 132 { 133 return gen_pool_alloc_algo_owner(pool, size, pool->algo, pool->data, 134 owner); 135 } 136 137 static inline unsigned long gen_pool_alloc_algo(struct gen_pool *pool, 138 size_t size, genpool_algo_t algo, void *data) 139 { 140 return gen_pool_alloc_algo_owner(pool, size, algo, data, NULL); 141 } 142 143 /** 144 * gen_pool_alloc - allocate special memory from the pool 145 * @pool: pool to allocate from 146 * @size: number of bytes to allocate from the pool 147 * 148 * Allocate the requested number of bytes from the specified pool. 149 * Uses the pool allocation function (with first-fit algorithm by default). 150 * Can not be used in NMI handler on architectures without 151 * NMI-safe cmpxchg implementation. 152 */ 153 static inline unsigned long gen_pool_alloc(struct gen_pool *pool, size_t size) 154 { 155 return gen_pool_alloc_algo(pool, size, pool->algo, pool->data); 156 } 157 158 extern void *gen_pool_dma_alloc(struct gen_pool *pool, size_t size, 159 dma_addr_t *dma); 160 extern void gen_pool_free_owner(struct gen_pool *pool, unsigned long addr, 161 size_t size, void **owner); 162 static inline void gen_pool_free(struct gen_pool *pool, unsigned long addr, 163 size_t size) 164 { 165 gen_pool_free_owner(pool, addr, size, NULL); 166 } 167 168 extern void gen_pool_for_each_chunk(struct gen_pool *, 169 void (*)(struct gen_pool *, struct gen_pool_chunk *, void *), void *); 170 extern size_t gen_pool_avail(struct gen_pool *); 171 extern size_t gen_pool_size(struct gen_pool *); 172 173 extern void gen_pool_set_algo(struct gen_pool *pool, genpool_algo_t algo, 174 void *data); 175 176 extern unsigned long gen_pool_first_fit(unsigned long *map, unsigned long size, 177 unsigned long start, unsigned int nr, void *data, 178 struct gen_pool *pool, unsigned long start_addr); 179 180 extern unsigned long gen_pool_fixed_alloc(unsigned long *map, 181 unsigned long size, unsigned long start, unsigned int nr, 182 void *data, struct gen_pool *pool, unsigned long start_addr); 183 184 extern unsigned long gen_pool_first_fit_align(unsigned long *map, 185 unsigned long size, unsigned long start, unsigned int nr, 186 void *data, struct gen_pool *pool, unsigned long start_addr); 187 188 189 extern unsigned long gen_pool_first_fit_order_align(unsigned long *map, 190 unsigned long size, unsigned long start, unsigned int nr, 191 void *data, struct gen_pool *pool, unsigned long start_addr); 192 193 extern unsigned long gen_pool_best_fit(unsigned long *map, unsigned long size, 194 unsigned long start, unsigned int nr, void *data, 195 struct gen_pool *pool, unsigned long start_addr); 196 197 198 extern struct gen_pool *devm_gen_pool_create(struct device *dev, 199 int min_alloc_order, int nid, const char *name); 200 extern struct gen_pool *gen_pool_get(struct device *dev, const char *name); 201 202 bool addr_in_gen_pool(struct gen_pool *pool, unsigned long start, 203 size_t size); 204 205 #ifdef CONFIG_OF 206 extern struct gen_pool *of_gen_pool_get(struct device_node *np, 207 const char *propname, int index); 208 #else 209 static inline struct gen_pool *of_gen_pool_get(struct device_node *np, 210 const char *propname, int index) 211 { 212 return NULL; 213 } 214 #endif 215 #endif /* __GENALLOC_H__ */ 216