[PATCH 5.19 0653/1157] iio: adc: max11100: Fix alignment for DMA safety

Greg Kroah-Hartman
2022-08-16T00:14:18Z

From: Jonathan Cameron <Jonathan.Cameron@huawei.com>

[ Upstream commit 51f30d63145cc84cb8a8e0ec96f9a8b73e6b5448 ]

____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: a8e7e88df9ec ("iio: adc: Add Maxim MAX11100 driver")
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Acked-by: Jacopo Mondi <jacopo@jmondi.org>
Acked-by: Nuno Sá <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20220508175712.647246-25-jic23@kernel.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/iio/adc/max11100.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/iio/adc/max11100.c b/drivers/iio/adc/max11100.c
index eb1ce6a0315c..49e38dca8fe2 100644
--- a/drivers/iio/adc/max11100.c
+++ b/drivers/iio/adc/max11100.c
@@ -33,10 +33,10 @@ struct max11100_state {
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.
*/
- u8 buffer[3] ____cacheline_aligned;
+ u8 buffer[3] __aligned(IIO_DMA_MINALIGN);
};

static const struct iio_chan_spec max11100_channels[] = {
--
2.35.1