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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>,
        Ricardo Ribalda <ribalda@kernel.org>,
        =?UTF-8?q?Nuno=20S=C3=A1?= <nuno.sa@analog.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.18 0648/1095] iio: dac: ti-dac7612: Fix alignment for DMA safety
Date:   Mon, 15 Aug 2022 20:00:47 +0200
Message-Id: <20220815180456.204927850@linuxfoundation.org>
In-Reply-To: <20220815180429.240518113@linuxfoundation.org>
References: <20220815180429.240518113@linuxfoundation.org>
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From: Jonathan Cameron <Jonathan.Cameron@huawei.com>

[ Upstream commit b9ac08b3282a95fcefb057c2886028a6807725d8 ]

____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.

Updated help text to 'may' require buffers to be in their own cacheline.

Fixes: 977724d20584 ("iio:dac:ti-dac7612: Add driver for Texas Instruments DAC7612")
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Ricardo Ribalda <ribalda@kernel.org>
Acked-by: Nuno Sá <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20220508175712.647246-65-jic23@kernel.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/iio/dac/ti-dac7612.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/iio/dac/ti-dac7612.c b/drivers/iio/dac/ti-dac7612.c
index 4c0f4b5e9ff4..8195815de26f 100644
--- a/drivers/iio/dac/ti-dac7612.c
+++ b/drivers/iio/dac/ti-dac7612.c
@@ -31,10 +31,10 @@ struct dac7612 {
 	struct mutex lock;
 
 	/*
-	 * DMA (thus cache coherency maintenance) requires the
+	 * DMA (thus cache coherency maintenance) may require the
 	 * transfer buffers to live in their own cache lines.
 	 */
-	uint8_t data[2] ____cacheline_aligned;
+	uint8_t data[2] __aligned(IIO_DMA_MINALIGN);
 };
 
 static int dac7612_cmd_single(struct dac7612 *priv, int channel, u16 val)
-- 
2.35.1