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    Subject[PATCH 5.19 0651/1157] iio: adc: ltc2497: Fix alignment for DMA safety
    Date
    From: Jonathan Cameron <Jonathan.Cameron@huawei.com>

    [ Upstream commit 6ebf401d555ee1e75e779b865d38e171db0aa1f2 ]

    ____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: bc82222fcca1 ("iio:adc: Driver for Linear Technology LTC2497 ADC")
    Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
    Cc: Michael Hennerich <michael.hennerich@analog.com>
    Acked-by: Nuno Sá <nuno.sa@analog.com>
    Link: https://lore.kernel.org/r/20220508175712.647246-23-jic23@kernel.org
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    drivers/iio/adc/ltc2497.c | 4 ++--
    1 file changed, 2 insertions(+), 2 deletions(-)

    diff --git a/drivers/iio/adc/ltc2497.c b/drivers/iio/adc/ltc2497.c
    index 1adddf5a88a9..f7c786f37ceb 100644
    --- a/drivers/iio/adc/ltc2497.c
    +++ b/drivers/iio/adc/ltc2497.c
    @@ -20,10 +20,10 @@ struct ltc2497_driverdata {
    struct ltc2497core_driverdata common_ddata;
    struct i2c_client *client;
    /*
    - * DMA (thus cache coherency maintenance) requires the
    + * DMA (thus cache coherency maintenance) may require the
    * transfer buffers to live in their own cache lines.
    */
    - __be32 buf ____cacheline_aligned;
    + __be32 buf __aligned(IIO_DMA_MINALIGN);
    };

    static int ltc2497_result_and_measure(struct ltc2497core_driverdata *ddata,
    --
    2.35.1


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