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 56 /* 57 * General purpose special memory pool descriptor. 58 */ 59 struct gen_pool { 60 spinlock_t lock; 61 struct list_head chunks; /* list of chunks in this pool */ 62 int min_alloc_order; /* minimum allocation order */ 63 64 genpool_algo_t algo; /* allocation function */ 65 void *data; 66 67 const char *name; 68 }; 69 70 /* 71 * General purpose special memory pool chunk descriptor. 72 */ 73 struct gen_pool_chunk { 74 struct list_head next_chunk; /* next chunk in pool */ 75 atomic_long_t avail; 76 phys_addr_t phys_addr; /* physical starting address of memory chunk */ 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[0]; /* bitmap for allocating memory chunk */ 80 }; 81 82 /* 83 * gen_pool data descriptor for gen_pool_first_fit_align. 84 */ 85 struct 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 */ 92 struct genpool_data_fixed { 93 unsigned long offset; /* The offset of the specific region */ 94 }; 95 96 extern struct gen_pool *gen_pool_create(int, int); 97 extern phys_addr_t gen_pool_virt_to_phys(struct gen_pool *pool, unsigned long); 98 extern int gen_pool_add_virt(struct gen_pool *, unsigned long, phys_addr_t, 99 size_t, int); 100 /** 101 * gen_pool_add - add a new chunk of special memory to the pool 102 * @pool: pool to add new memory chunk to 103 * @addr: starting address of memory chunk to add to pool 104 * @size: size in bytes of the memory chunk to add to pool 105 * @nid: node id of the node the chunk structure and bitmap should be 106 * allocated on, or -1 107 * 108 * Add a new chunk of special memory to the specified pool. 109 * 110 * Returns 0 on success or a -ve errno on failure. 111 */ 112 static inline int gen_pool_add(struct gen_pool *pool, unsigned long addr, 113 size_t size, int nid) 114 { 115 return gen_pool_add_virt(pool, addr, -1, size, nid); 116 } 117 extern void gen_pool_destroy(struct gen_pool *); 118 extern unsigned long gen_pool_alloc(struct gen_pool *, size_t); 119 extern unsigned long gen_pool_alloc_algo(struct gen_pool *, size_t, 120 genpool_algo_t algo, void *data); 121 extern void *gen_pool_dma_alloc(struct gen_pool *pool, size_t size, 122 dma_addr_t *dma); 123 extern void gen_pool_free(struct gen_pool *, unsigned long, size_t); 124 extern void gen_pool_for_each_chunk(struct gen_pool *, 125 void (*)(struct gen_pool *, struct gen_pool_chunk *, void *), void *); 126 extern size_t gen_pool_avail(struct gen_pool *); 127 extern size_t gen_pool_size(struct gen_pool *); 128 129 extern void gen_pool_set_algo(struct gen_pool *pool, genpool_algo_t algo, 130 void *data); 131 132 extern unsigned long gen_pool_first_fit(unsigned long *map, unsigned long size, 133 unsigned long start, unsigned int nr, void *data, 134 struct gen_pool *pool); 135 136 extern unsigned long gen_pool_fixed_alloc(unsigned long *map, 137 unsigned long size, unsigned long start, unsigned int nr, 138 void *data, struct gen_pool *pool); 139 140 extern unsigned long gen_pool_first_fit_align(unsigned long *map, 141 unsigned long size, unsigned long start, unsigned int nr, 142 void *data, struct gen_pool *pool); 143 144 145 extern unsigned long gen_pool_first_fit_order_align(unsigned long *map, 146 unsigned long size, unsigned long start, unsigned int nr, 147 void *data, struct gen_pool *pool); 148 149 extern unsigned long gen_pool_best_fit(unsigned long *map, unsigned long size, 150 unsigned long start, unsigned int nr, void *data, 151 struct gen_pool *pool); 152 153 154 extern struct gen_pool *devm_gen_pool_create(struct device *dev, 155 int min_alloc_order, int nid, const char *name); 156 extern struct gen_pool *gen_pool_get(struct device *dev, const char *name); 157 158 bool addr_in_gen_pool(struct gen_pool *pool, unsigned long start, 159 size_t size); 160 161 #ifdef CONFIG_OF 162 extern struct gen_pool *of_gen_pool_get(struct device_node *np, 163 const char *propname, int index); 164 #else 165 static inline struct gen_pool *of_gen_pool_get(struct device_node *np, 166 const char *propname, int index) 167 { 168 return NULL; 169 } 170 #endif 171 #endif /* __GENALLOC_H__ */ 172