lkml.org 
[lkml]   [2022]   [Aug]   [15]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 5.18 0593/1095] iio: adc: ad7266: Fix alignment for DMA safety
    Date
    From: Jonathan Cameron <Jonathan.Cameron@huawei.com>

    [ Upstream commit b990cdfe7536a8da7e134d516350402981300016 ]

    ____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 reflect that DMA safety 'may' require separate
    cachelines.

    Fixes: 54e018da3141 ("iio:ad7266: Mark transfer buffer as __be16")
    Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
    Acked-by: Nuno Sá <nuno.sa@analog.com>
    Link: https://lore.kernel.org/r/20220508175712.647246-10-jic23@kernel.org
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    drivers/iio/adc/ad7266.c | 4 ++--
    1 file changed, 2 insertions(+), 2 deletions(-)

    diff --git a/drivers/iio/adc/ad7266.c b/drivers/iio/adc/ad7266.c
    index c17d9b5fbaf6..53c83e04dde5 100644
    --- a/drivers/iio/adc/ad7266.c
    +++ b/drivers/iio/adc/ad7266.c
    @@ -37,7 +37,7 @@ struct ad7266_state {
    struct gpio_desc *gpios[3];

    /*
    - * DMA (thus cache coherency maintenance) requires the
    + * DMA (thus cache coherency maintenance) may require the
    * transfer buffers to live in their own cache lines.
    * The buffer needs to be large enough to hold two samples (4 bytes) and
    * the naturally aligned timestamp (8 bytes).
    @@ -45,7 +45,7 @@ struct ad7266_state {
    struct {
    __be16 sample[2];
    s64 timestamp;
    - } data ____cacheline_aligned;
    + } data __aligned(IIO_DMA_MINALIGN);
    };

    static int ad7266_wakeup(struct ad7266_state *st)
    --
    2.35.1


    \
     
     \ /
      Last update: 2022-08-15 23:35    [W:4.043 / U:1.548 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site