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authorNicolin Chen <b42378@freescale.com>2013-11-12 15:09:52 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2013-11-13 12:09:22 +0900
commit684f0d3d14f2744ae7ad79063b21909e32bf444e (patch)
tree0f09fcd01b3471b97bf611c6257f66afcf135fae /lib/genalloc.c
parentff6092a8a413f3db1938b4606e078fa751ed6cdb (diff)
downloadlinux-684f0d3d14f2744ae7ad79063b21909e32bf444e.tar.gz
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: Nicolin 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: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'lib/genalloc.c')
-rw-r--r--lib/genalloc.c28
1 files changed, 28 insertions, 0 deletions
diff --git a/lib/genalloc.c b/lib/genalloc.c
index 26cf20be72b7..dda31168844f 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