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Commit 684f0d3d authored by Nicolin Chen's avatar Nicolin Chen Committed by Linus Torvalds
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lib/genalloc: add a helper function for DMA buffer allocation 



When using pool space for DMA buffer, there might be duplicated calling of
gen_pool_alloc() and gen_pool_virt_to_phys() in each implementation.

Thus it's better to add a simple helper function, a compatible one to the
common dma_alloc_coherent(), to save some code.

Signed-off-by: default avatarNicolin Chen <b42378@freescale.com>
Cc: "Hans J. Koch" <hjk@hansjkoch.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Eric Miao <eric.y.miao@gmail.com>
Cc: Grant Likely <grant.likely@linaro.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Haojian Zhuang <haojian.zhuang@gmail.com>
Cc: Jaroslav Kysela <perex@perex.cz>
Cc: Kevin Hilman <khilman@deeprootsystems.com>
Cc: Liam Girdwood <lgirdwood@gmail.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Mauro Carvalho Chehab <m.chehab@samsung.com>
Cc: Rob Herring <rob.herring@calxeda.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Sekhar Nori <nsekhar@ti.com>
Cc: Takashi Iwai <tiwai@suse.de>
Cc: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent ff6092a8

include/linux/genalloc.h

+2 −0
Original line number Original line Diff line number Diff line
@@ -94,6 +94,8 @@ static inline int gen_pool_add(struct gen_pool *pool, unsigned long addr, 
}

}

extern void gen_pool_destroy(struct gen_pool *);

extern void gen_pool_destroy(struct gen_pool *);

extern unsigned long gen_pool_alloc(struct gen_pool *, size_t);

extern unsigned long gen_pool_alloc(struct gen_pool *, size_t);

extern void *gen_pool_dma_alloc(struct gen_pool *pool, size_t size,

		dma_addr_t *dma);

extern void gen_pool_free(struct gen_pool *, unsigned long, size_t);

extern void gen_pool_free(struct gen_pool *, unsigned long, size_t);

extern void gen_pool_for_each_chunk(struct gen_pool *,

extern void gen_pool_for_each_chunk(struct gen_pool *,

	void (*)(struct gen_pool *, struct gen_pool_chunk *, void *), void *);

	void (*)(struct gen_pool *, struct gen_pool_chunk *, void *), void *);

lib/genalloc.c

+28 −0
Original line number Original line Diff line number Diff line
@@ -312,6 +312,34 @@ unsigned long gen_pool_alloc(struct gen_pool *pool, size_t size) 
}

}

EXPORT_SYMBOL(gen_pool_alloc);

EXPORT_SYMBOL(gen_pool_alloc);





/**

 * gen_pool_dma_alloc - allocate special memory from the pool for DMA usage

 * @pool: pool to allocate from

 * @size: number of bytes to allocate from the pool

 * @dma: dma-view physical address

 *

 * Allocate the requested number of bytes from the specified pool.

 * Uses the pool allocation function (with first-fit algorithm by default).

 * Can not be used in NMI handler on architectures without

 * NMI-safe cmpxchg implementation.

 */

void *gen_pool_dma_alloc(struct gen_pool *pool, size_t size, dma_addr_t *dma)

{

	unsigned long vaddr;



	if (!pool)

		return NULL;



	vaddr = gen_pool_alloc(pool, size);

	if (!vaddr)

		return NULL;



	*dma = gen_pool_virt_to_phys(pool, vaddr);



	return (void *)vaddr;

}

EXPORT_SYMBOL(gen_pool_dma_alloc);



/**

/**

 * gen_pool_free - free allocated special memory back to the pool

 * gen_pool_free - free allocated special memory back to the pool

 * @pool: pool to free to

 * @pool: pool to free to