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 unsigned long start_addr; /* start address of memory chunk */ 79 unsigned long end_addr; /* end address of memory chunk (inclusive) */ 80 unsigned long bits[0]; /* bitmap for allocating memory chunk */ 81 }; 82 83 /* 84 * gen_pool data descriptor for gen_pool_first_fit_align. 85 */ 86 struct genpool_data_align { 87 int align; /* alignment by bytes for starting address */ 88 }; 89 90 /* 91 * gen_pool data descriptor for gen_pool_fixed_alloc. 92 */ 93 struct genpool_data_fixed { 94 unsigned long offset; /* The offset of the specific region */ 95 }; 96 97 extern struct gen_pool *gen_pool_create(int, int); 98 extern phys_addr_t gen_pool_virt_to_phys(struct gen_pool *pool, unsigned long); 99 extern int gen_pool_add_virt(struct gen_pool *, unsigned long, phys_addr_t, 100 size_t, int); 101 /** 102 * gen_pool_add - add a new chunk of special memory to the pool 103 * @pool: pool to add new memory chunk to 104 * @addr: starting address of memory chunk to add to pool 105 * @size: size in bytes of the memory chunk to add to pool 106 * @nid: node id of the node the chunk structure and bitmap should be 107 * allocated on, or -1 108 * 109 * Add a new chunk of special memory to the specified pool. 110 * 111 * Returns 0 on success or a -ve errno on failure. 112 */ 113 static inline int gen_pool_add(struct gen_pool *pool, unsigned long addr, 114 size_t size, int nid) 115 { 116 return gen_pool_add_virt(pool, addr, -1, size, nid); 117 } 118 extern void gen_pool_destroy(struct gen_pool *); 119 extern unsigned long gen_pool_alloc(struct gen_pool *, size_t); 120 extern unsigned long gen_pool_alloc_algo(struct gen_pool *, size_t, 121 genpool_algo_t algo, void *data); 122 extern void *gen_pool_dma_alloc(struct gen_pool *pool, size_t size, 123 dma_addr_t *dma); 124 extern void gen_pool_free(struct gen_pool *, unsigned long, size_t); 125 extern void gen_pool_for_each_chunk(struct gen_pool *, 126 void (*)(struct gen_pool *, struct gen_pool_chunk *, void *), void *); 127 extern size_t gen_pool_avail(struct gen_pool *); 128 extern size_t gen_pool_size(struct gen_pool *); 129 130 extern void gen_pool_set_algo(struct gen_pool *pool, genpool_algo_t algo, 131 void *data); 132 133 extern unsigned long gen_pool_first_fit(unsigned long *map, unsigned long size, 134 unsigned long start, unsigned int nr, void *data, 135 struct gen_pool *pool, unsigned long start_addr); 136 137 extern unsigned long gen_pool_fixed_alloc(unsigned long *map, 138 unsigned long size, unsigned long start, unsigned int nr, 139 void *data, struct gen_pool *pool, unsigned long start_addr); 140 141 extern unsigned long gen_pool_first_fit_align(unsigned long *map, 142 unsigned long size, unsigned long start, unsigned int nr, 143 void *data, struct gen_pool *pool, unsigned long start_addr); 144 145 146 extern unsigned long gen_pool_first_fit_order_align(unsigned long *map, 147 unsigned long size, unsigned long start, unsigned int nr, 148 void *data, struct gen_pool *pool, unsigned long start_addr); 149 150 extern unsigned long gen_pool_best_fit(unsigned long *map, unsigned long size, 151 unsigned long start, unsigned int nr, void *data, 152 struct gen_pool *pool, unsigned long start_addr); 153 154 155 extern struct gen_pool *devm_gen_pool_create(struct device *dev, 156 int min_alloc_order, int nid, const char *name); 157 extern struct gen_pool *gen_pool_get(struct device *dev, const char *name); 158 159 bool addr_in_gen_pool(struct gen_pool *pool, unsigned long start, 160 size_t size); 161 162 #ifdef CONFIG_OF 163 extern struct gen_pool *of_gen_pool_get(struct device_node *np, 164 const char *propname, int index); 165 #else 166 static inline struct gen_pool *of_gen_pool_get(struct device_node *np, 167 const char *propname, int index) 168 { 169 return NULL; 170 } 171 #endif 172 #endif /* __GENALLOC_H__ */ 173