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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Jonathan Cameron <Jonathan.Cameron@huawei.com>,
        =?UTF-8?q?Nuno=20S=C3=A1?= <nuno.sa@analog.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.19 0670/1157] iio: amplifiers: ad8366: Fix alignment for DMA safety
Date:   Mon, 15 Aug 2022 20:00:26 +0200
Message-Id: <20220815180506.497676006@linuxfoundation.org>
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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