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[v2,14/92] iio: adc: ad7606: Fix alignment for DMA safety

Message ID 20220508175712.647246-15-jic23@kernel.org (mailing list archive)
State Accepted
Headers show
Series IIO: Fix alignment of buffers for DMA | expand

Commit Message

Jonathan Cameron May 8, 2022, 5:55 p.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 reflect the fact DMA safety 'may' require
separate cachelines.

Fixes: 7989b4bb23fe ("iio: adc: ad7616: Add support for AD7616 ADC")
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Acked-by: Nuno Sá <nuno.sa@analog.com>
---
 drivers/iio/adc/ad7606.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
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Patch

diff --git a/drivers/iio/adc/ad7606.h b/drivers/iio/adc/ad7606.h
index 4f82d7c9acfd..2dc4f599f9df 100644
--- a/drivers/iio/adc/ad7606.h
+++ b/drivers/iio/adc/ad7606.h
@@ -116,11 +116,11 @@  struct ad7606_state {
 	struct completion		completion;
 
 	/*
-	 * DMA (thus cache coherency maintenance) requires the
+	 * DMA (thus cache coherency maintenance) may require the
 	 * transfer buffers to live in their own cache lines.
 	 * 16 * 16-bit samples + 64-bit timestamp
 	 */
-	unsigned short			data[20] ____cacheline_aligned;
+	unsigned short			data[20] __aligned(IIO_DMA_MINALIGN);
 	__be16				d16[2];
 };