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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>,
        David Lechner <david@lechnology.com>,
        =?UTF-8?q?Nuno=20S=C3=A1?= <nuno.sa@analog.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.19 0665/1157] iio: adc: ti-ads7950: Fix alignment for DMA safety
Date:   Mon, 15 Aug 2022 20:00:21 +0200
Message-Id: <20220815180506.324370871@linuxfoundation.org>
In-Reply-To: <20220815180439.416659447@linuxfoundation.org>
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From: Jonathan Cameron <Jonathan.Cameron@huawei.com>

[ Upstream commit dd54ba8b2469f6ae665c529623a9454ce5293ca8 ]

____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: 902c4b2446d4 ("iio: adc: New driver for TI ADS7950 chips")
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Acked-by: David Lechner <david@lechnology.com>
Acked-by: Nuno Sá <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20220508175712.647246-37-jic23@kernel.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/iio/adc/ti-ads7950.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/iio/adc/ti-ads7950.c b/drivers/iio/adc/ti-ads7950.c
index e3658b969c5b..2cc9a9bd9db6 100644
--- a/drivers/iio/adc/ti-ads7950.c
+++ b/drivers/iio/adc/ti-ads7950.c
@@ -102,11 +102,11 @@ struct ti_ads7950_state {
 	unsigned int		gpio_cmd_settings_bitmask;
 
 	/*
-	 * DMA (thus cache coherency maintenance) requires the
+	 * DMA (thus cache coherency maintenance) may require the
 	 * transfer buffers to live in their own cache lines.
 	 */
 	u16 rx_buf[TI_ADS7950_MAX_CHAN + 2 + TI_ADS7950_TIMESTAMP_SIZE]
-							____cacheline_aligned;
+		__aligned(IIO_DMA_MINALIGN);
 	u16 tx_buf[TI_ADS7950_MAX_CHAN + 2];
 	u16 single_tx;
 	u16 single_rx;
-- 
2.35.1