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authorKuninori Morimoto <kuninori.morimoto.gx@renesas.com>2012-04-25 20:50:53 +0200
committerVinod Koul <vinod.koul@linux.intel.com>2012-05-11 12:04:39 +0530
commit922ee08baad2052d0759f100e026d49798c51fef (patch)
tree516d14b41b5831c2b7a571ad5851ef6d00062f14 /include/linux/dmaengine.h
parentfdaf9c4b22247a6cc6cda9459be3e52764c14d95 (diff)
downloadlwn-922ee08baad2052d0759f100e026d49798c51fef.tar.gz
lwn-922ee08baad2052d0759f100e026d49798c51fef.zip
dmaengine: Fixup dmaengine_prep_slave_single() to be actually useful
dmaengine_prep_slave_single() is a helper function which is supposed to be used to prepare a transfer of a single contingous buffer. Currently the function takes a pointer to such a buffer from which it builds a scatterlist and passes it on to device_prep_slave_sg. The dmaengine framework requires that any scatterlist that is passed to device_prep_slave_sg is mapped and it may not be unmapped until the DMA operation has completed. This is not the here and any use of dmaengine_prep_slave_single() will lead to undefined behaviour (Most likely a system crash). This patch changes dmaengine_prep_slave_single() to take a dma_addr_t instead of a pointer to a buffer and moves the responsibility of mapping and unmapping the buffer up to the caller. Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com> Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> Acked-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Vinod Koul <vinod.koul@linux.intel.com>
Diffstat (limited to 'include/linux/dmaengine.h')
-rw-r--r--include/linux/dmaengine.h6
1 files changed, 4 insertions, 2 deletions
diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
index 676f967390ae..0e6b595e95c8 100644
--- a/include/linux/dmaengine.h
+++ b/include/linux/dmaengine.h
@@ -615,11 +615,13 @@ static inline int dmaengine_slave_config(struct dma_chan *chan,
}
static inline struct dma_async_tx_descriptor *dmaengine_prep_slave_single(
- struct dma_chan *chan, void *buf, size_t len,
+ struct dma_chan *chan, dma_addr_t buf, size_t len,
enum dma_transfer_direction dir, unsigned long flags)
{
struct scatterlist sg;
- sg_init_one(&sg, buf, len);
+ sg_init_table(&sg, 1);
+ sg_dma_address(&sg) = buf;
+ sg_dma_len(&sg) = len;
return chan->device->device_prep_slave_sg(chan, &sg, 1,
dir, flags, NULL);