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iio: adc: ad_sigma_delta: ensure proper DMA alignment

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commit 59598510be 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: 0fb6ee8d0b ("iio: ad_sigma_delta: Don't put SPI transfer buffer on the stack")
Signed-off-by: Nuno Sa <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20240117-dev_sigma_delta_no_irq_flags-v1-1-db39261592cf@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>
This commit is contained in:
Nuno Sa 2024-01-17 13:41:03 +01:00 • committed by Greg Kroah-Hartman
commit 18cbe28671
1 changed files with 3 additions and 1 deletions
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4
include/linux/iio/adc/ad_sigma_delta.h
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@ -8,6 +8,8 @@
#ifndef __AD_SIGMA_DELTA_H__
#define __AD_SIGMA_DELTA_H__
#include <linux/iio/iio.h>
enum ad_sigma_delta_mode {
AD_SD_MODE_CONTINUOUS = 0,
AD_SD_MODE_SINGLE = 1,
@ -99,7 +101,7 @@ struct ad_sigma_delta {
* 'rx_buf' is up to 32 bits per sample + 64 bit timestamp,
* rounded to 16 bytes to take into account padding.
*/
uint8_t tx_buf[4] ____cacheline_aligned;
uint8_t tx_buf[4] __aligned(IIO_DMA_MINALIGN);
uint8_t rx_buf[16] __aligned(8);
};