[PATCH 6.1 107/197] iio: imu: adis: ensure proper DMA alignment

Greg Kroah-Hartman
2024-02-20T21:05:06Z

From: Nuno Sa <nuno.sa@analog.com>

commit 8e98b87f515d8c4bae521048a037b2cc431c3fd5 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 the sigma_delta ADCs.

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

Fixes: ccd2b52f4ac6 ("staging:iio: Add common ADIS library")
Signed-off-by: Nuno Sa <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20240117-adis-improv-v1-1-7f90e9fad200@analog.com
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
include/linux/iio/imu/adis.h | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

--- a/include/linux/iio/imu/adis.h
+++ b/include/linux/iio/imu/adis.h
@@ -11,6 +11,7 @@

#include <linux/spi/spi.h>
#include <linux/interrupt.h>
+#include <linux/iio/iio.h>
#include <linux/iio/types.h>

#define ADIS_WRITE_REG(reg) ((0x80 | (reg)))
@@ -131,7 +132,7 @@ struct adis {
unsigned long irq_flag;
void *buffer;

- u8 tx[10] ____cacheline_aligned;
+ u8 tx[10] __aligned(IIO_DMA_MINALIGN);
u8 rx[4];
};