[PATCH 5.19 0670/1157] iio: amplifiers: ad8366: Fix alignment for DMA safety

Greg Kroah-Hartman
2022-08-16T00:14:17Z

From: Jonathan Cameron <Jonathan.Cameron@huawei.com>

[ Upstream commit 026bffa458d029a5f15ac3f82a9bb0f64aca403d ]

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

Update the comment to include 'may'.

Fixes: e71d42e03c60 ("iio: amplifiers: New driver for AD8366 Dual-Digital Variable Gain Amplifier")
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Acked-by: Nuno Sá <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20220508175712.647246-42-jic23@kernel.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/iio/amplifiers/ad8366.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/iio/amplifiers/ad8366.c b/drivers/iio/amplifiers/ad8366.c
index 1134ae12e531..f2c2ea79a07f 100644
--- a/drivers/iio/amplifiers/ad8366.c
+++ b/drivers/iio/amplifiers/ad8366.c
@@ -45,10 +45,10 @@ struct ad8366_state {
enum ad8366_type type;
struct ad8366_info *info;
/*
- * DMA (thus cache coherency maintenance) requires the
+ * DMA (thus cache coherency maintenance) may require the
* transfer buffers to live in their own cache lines.
*/
- unsigned char data[2] ____cacheline_aligned;
+ unsigned char data[2] __aligned(IIO_DMA_MINALIGN);
};

static struct ad8366_info ad8366_infos[] = {
--
2.35.1