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| author | Alexander Stein <alexander.stein@systec-electronic.com> | 2011-05-05 08:40:14 -0700 |
|---|---|---|
| committer | Dmitry Torokhov <dmitry.torokhov@gmail.com> | 2011-05-05 08:50:47 -0700 |
| commit | 1dbe7dada2d03d1313183d439068f1f951a91244 (patch) | |
| tree | 49f79d5fbaf5fc982f7a7742f94ed465a69220a9 | |
| parent | bf283707d5fb174ec09215ae19860ad04ba7b67a (diff) | |
| download | linux-1dbe7dada2d03d1313183d439068f1f951a91244.tar.gz linux-1dbe7dada2d03d1313183d439068f1f951a91244.tar.bz2 linux-1dbe7dada2d03d1313183d439068f1f951a91244.zip | |
Input: ads7846 - make transfer buffers DMA safe
req.sample needs its own cacheline otherwise accessing req.msg fetches
it in again.
Note: This effect doesn't occur if the underlying SPI driver doesn't use
DMA at all.
Signed-off-by: Alexander Stein <alexander.stein@systec-electronic.com>
Acked-by: Jonathan Cameron <jic23@cam.ac.uk>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
| -rw-r--r-- | drivers/input/touchscreen/ads7846.c | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/drivers/input/touchscreen/ads7846.c b/drivers/input/touchscreen/ads7846.c index c24946f51256..ab51a8dbdb5a 100644 --- a/drivers/input/touchscreen/ads7846.c +++ b/drivers/input/touchscreen/ads7846.c @@ -281,17 +281,25 @@ struct ser_req { u8 command; u8 ref_off; u16 scratch; - __be16 sample; struct spi_message msg; struct spi_transfer xfer[6]; + /* + * DMA (thus cache coherency maintenance) requires the + * transfer buffers to live in their own cache lines. + */ + __be16 sample ____cacheline_aligned; }; struct ads7845_ser_req { u8 command[3]; u8 pwrdown[3]; - u8 sample[3]; struct spi_message msg; struct spi_transfer xfer[2]; + /* + * DMA (thus cache coherency maintenance) requires the + * transfer buffers to live in their own cache lines. + */ + u8 sample[3] ____cacheline_aligned; }; static int ads7846_read12_ser(struct device *dev, unsigned command) |