genalloc.h 5.68 KB
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/*
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 * Basic general purpose allocator for managing special purpose
 * memory, for example, memory that is not managed by the regular
 * kmalloc/kfree interface.  Uses for this includes on-device special
 * memory, uncached memory etc.
 *
 * It is safe to use the allocator in NMI handlers and other special
 * unblockable contexts that could otherwise deadlock on locks.  This
 * is implemented by using atomic operations and retries on any
 * conflicts.  The disadvantage is that there may be livelocks in
 * extreme cases.  For better scalability, one allocator can be used
 * for each CPU.
 *
 * The lockless operation only works if there is enough memory
 * available.  If new memory is added to the pool a lock has to be
 * still taken.  So any user relying on locklessness has to ensure
 * that sufficient memory is preallocated.
 *
 * The basic atomic operation of this allocator is cmpxchg on long.
 * On architectures that don't have NMI-safe cmpxchg implementation,
 * the allocator can NOT be used in NMI handler.  So code uses the
 * allocator in NMI handler should depend on
 * CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG.
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 *
 * This source code is licensed under the GNU General Public License,
 * Version 2.  See the file COPYING for more details.
 */


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#ifndef __GENALLOC_H__
#define __GENALLOC_H__
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#include <linux/types.h>
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#include <linux/spinlock_types.h>

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struct device;
struct device_node;
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struct gen_pool;
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/**
 * Allocation callback function type definition
 * @map: Pointer to bitmap
 * @size: The bitmap size in bits
 * @start: The bitnumber to start searching at
 * @nr: The number of zeroed bits we're looking for
 * @data: optional additional data used by @genpool_algo_t
 */
typedef unsigned long (*genpool_algo_t)(unsigned long *map,
			unsigned long size,
			unsigned long start,
			unsigned int nr,
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			void *data, struct gen_pool *pool);
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/*
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 *  General purpose special memory pool descriptor.
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 */
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struct gen_pool {
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	spinlock_t lock;
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	struct list_head chunks;	/* list of chunks in this pool */
	int min_alloc_order;		/* minimum allocation order */
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	genpool_algo_t algo;		/* allocation function */
	void *data;
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	const char *name;
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};

/*
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 *  General purpose special memory pool chunk descriptor.
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 */
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struct gen_pool_chunk {
	struct list_head next_chunk;	/* next chunk in pool */
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	atomic_t avail;
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	phys_addr_t phys_addr;		/* physical starting address of memory chunk */
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	unsigned long start_addr;	/* start address of memory chunk */
	unsigned long end_addr;		/* end address of memory chunk (inclusive) */
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	unsigned long bits[0];		/* bitmap for allocating memory chunk */
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};

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/*
 *  gen_pool data descriptor for gen_pool_first_fit_align.
 */
struct genpool_data_align {
	int align;		/* alignment by bytes for starting address */
};

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/*
 *  gen_pool data descriptor for gen_pool_fixed_alloc.
 */
struct genpool_data_fixed {
	unsigned long offset;		/* The offset of the specific region */
};

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extern struct gen_pool *gen_pool_create(int, int);
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extern phys_addr_t gen_pool_virt_to_phys(struct gen_pool *pool, unsigned long);
extern int gen_pool_add_virt(struct gen_pool *, unsigned long, phys_addr_t,
			     size_t, int);
/**
 * gen_pool_add - add a new chunk of special memory to the pool
 * @pool: pool to add new memory chunk to
 * @addr: starting address of memory chunk to add to pool
 * @size: size in bytes of the memory chunk to add to pool
 * @nid: node id of the node the chunk structure and bitmap should be
 *       allocated on, or -1
 *
 * Add a new chunk of special memory to the specified pool.
 *
 * Returns 0 on success or a -ve errno on failure.
 */
static inline int gen_pool_add(struct gen_pool *pool, unsigned long addr,
			       size_t size, int nid)
{
	return gen_pool_add_virt(pool, addr, -1, size, nid);
}
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extern void gen_pool_destroy(struct gen_pool *);
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extern unsigned long gen_pool_alloc(struct gen_pool *, size_t);
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extern unsigned long gen_pool_alloc_algo(struct gen_pool *, size_t,
		genpool_algo_t algo, void *data);
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extern void *gen_pool_dma_alloc(struct gen_pool *pool, size_t size,
		dma_addr_t *dma);
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extern void gen_pool_free(struct gen_pool *, unsigned long, size_t);
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extern void gen_pool_for_each_chunk(struct gen_pool *,
	void (*)(struct gen_pool *, struct gen_pool_chunk *, void *), void *);
extern size_t gen_pool_avail(struct gen_pool *);
extern size_t gen_pool_size(struct gen_pool *);
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extern void gen_pool_set_algo(struct gen_pool *pool, genpool_algo_t algo,
		void *data);

extern unsigned long gen_pool_first_fit(unsigned long *map, unsigned long size,
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		unsigned long start, unsigned int nr, void *data,
		struct gen_pool *pool);

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extern unsigned long gen_pool_fixed_alloc(unsigned long *map,
		unsigned long size, unsigned long start, unsigned int nr,
		void *data, struct gen_pool *pool);

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extern unsigned long gen_pool_first_fit_align(unsigned long *map,
		unsigned long size, unsigned long start, unsigned int nr,
		void *data, struct gen_pool *pool);

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extern unsigned long gen_pool_first_fit_order_align(unsigned long *map,
		unsigned long size, unsigned long start, unsigned int nr,
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		void *data, struct gen_pool *pool);
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extern unsigned long gen_pool_best_fit(unsigned long *map, unsigned long size,
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		unsigned long start, unsigned int nr, void *data,
		struct gen_pool *pool);

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extern struct gen_pool *devm_gen_pool_create(struct device *dev,
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		int min_alloc_order, int nid, const char *name);
extern struct gen_pool *gen_pool_get(struct device *dev, const char *name);
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bool addr_in_gen_pool(struct gen_pool *pool, unsigned long start,
			size_t size);

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#ifdef CONFIG_OF
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extern struct gen_pool *of_gen_pool_get(struct device_node *np,
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	const char *propname, int index);
#else
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static inline struct gen_pool *of_gen_pool_get(struct device_node *np,
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	const char *propname, int index)
{
	return NULL;
}
#endif
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#endif /* __GENALLOC_H__ */