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    Subject[PATCH 5.19 0650/1157] iio: adc: ltc2496: Fix alignment for DMA safety
    Date
    From: Jonathan Cameron <Jonathan.Cameron@huawei.com>

    [ Upstream commit 1673b7ca2dc1fb3b8d7c94a112496c02d34ae449 ]

    ____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: e4c5c4dfaa88 ("iio: adc: new driver to support Linear technology's ltc2496")
    Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
    Cc: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
    Acked-by: Nuno Sá <nuno.sa@analog.com>
    Link: https://lore.kernel.org/r/20220508175712.647246-22-jic23@kernel.org
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    drivers/iio/adc/ltc2496.c | 4 ++--
    1 file changed, 2 insertions(+), 2 deletions(-)

    diff --git a/drivers/iio/adc/ltc2496.c b/drivers/iio/adc/ltc2496.c
    index 5a55f79f2574..dfb3bb5997e5 100644
    --- a/drivers/iio/adc/ltc2496.c
    +++ b/drivers/iio/adc/ltc2496.c
    @@ -24,10 +24,10 @@ struct ltc2496_driverdata {
    struct spi_device *spi;

    /*
    - * 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 rxbuf[3] ____cacheline_aligned;
    + unsigned char rxbuf[3] __aligned(IIO_DMA_MINALIGN);
    unsigned char txbuf[3];
    };

    --
    2.35.1


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