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[18/92] iio: adc: ad7923: Fix alignment for DMA safety

Message ID 20220503085935.1533814-19-jic23@kernel.org (mailing list archive)
State Superseded
Headers show
Series IIO: Fix alignment of buffers for DMA | expand

Commit Message

Jonathan Cameron May 3, 2022, 8:58 a.m. UTC 
From: Jonathan Cameron <Jonathan.Cameron@huawei.com>

____cacheline_aligned is an insufficient guarantee for non-coherent DMA
on platforms with 128 byte cachelines above L1.  Switch to the updated
IIO_ALIGN definition.

Update the comment to include 'may'.

Note that some other fixes have applied to this line of code
that may complicate automated backporting.

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Fixes: 0eac259db28f ("IIO ADC support for AD7923")
---
 drivers/iio/adc/ad7923.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/drivers/iio/adc/ad7923.c b/drivers/iio/adc/ad7923.c
index 069b561ee768..596244bccd20 100644
--- a/drivers/iio/adc/ad7923.c
+++ b/drivers/iio/adc/ad7923.c
@@ -57,12 +57,12 @@  struct ad7923_state {
 	unsigned int			settings;
 
 	/*
-	 * DMA (thus cache coherency maintenance) requires the
+	 * DMA (thus cache coherency maintenance) may require the
 	 * transfer buffers to live in their own cache lines.
 	 * Ensure rx_buf can be directly used in iio_push_to_buffers_with_timetamp
 	 * Length = 8 channels + 4 extra for 8 byte timestamp
 	 */
-	__be16				rx_buf[12] ____cacheline_aligned;
+	__be16				rx_buf[12] __aligned(IIO_ALIGN);
 	__be16				tx_buf[4];
 };