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: Nicolin Chen b42378@freescale.com --- include/linux/genalloc.h | 2 ++ lib/genalloc.c | 28 ++++++++++++++++++++++++++++ 2 files changed, 30 insertions(+)
diff --git a/include/linux/genalloc.h b/include/linux/genalloc.h index f8d41cb..1eda33d 100644 --- a/include/linux/genalloc.h +++ b/include/linux/genalloc.h @@ -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 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_for_each_chunk(struct gen_pool *, void (*)(struct gen_pool *, struct gen_pool_chunk *, void *), void *); diff --git a/lib/genalloc.c b/lib/genalloc.c index 26cf20b..dda3116 100644 --- a/lib/genalloc.c +++ b/lib/genalloc.c @@ -313,6 +313,34 @@ retry: 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 * @pool: pool to free to * @addr: starting address of memory to free back to pool