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iio: commom: st_sensors: ensure proper DMA alignment

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commit 862cf85fef upstream.

Aligning the buffer to the L1 cache is not sufficient in some platforms
as they might have larger cacheline sizes for caches after L1 and thus,
we can't guarantee DMA safety.

That was the whole reason to introduce IIO_DMA_MINALIGN in [1]. Do the same
for st_sensors common buffer.

While at it, moved the odr_lock before buffer_data as we definitely
don't want any other data to share a cacheline with the buffer.

[1]: https://lore.kernel.org/linux-iio/20220508175712.647246-2-jic23@kernel.org/

Fixes: e031d5f558 ("iio:st_sensors: remove buffer allocation at each buffer enable")
Signed-off-by: Nuno Sa <nuno.sa@analog.com>
Cc: <Stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20240131-dev_dma_safety_stm-v2-1-580c07fae51b@analog.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Nuno Sa 2024-01-31 10:16:47 +01:00 committed by Greg Kroah-Hartman
parent 359f220d0e
commit 4f10423c0e
1 changed files with 2 additions and 2 deletions
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4
include/linux/iio/common/st_sensors.h
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@ -261,9 +261,9 @@ struct st_sensor_data {
bool hw_irq_trigger;
s64 hw_timestamp;
char buffer_data[ST_SENSORS_MAX_BUFFER_SIZE] ____cacheline_aligned;
struct mutex odr_lock;
char buffer_data[ST_SENSORS_MAX_BUFFER_SIZE] __aligned(IIO_DMA_MINALIGN);
};
#ifdef CONFIG_IIO_BUFFER