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[v2,04/92] iio: accel: adxl367: Fix alignment for DMA safety

Message ID 20220508175712.647246-5-jic23@kernel.org (mailing list archive)
State Accepted
Headers show
Series IIO: Fix alignment of buffers for DMA | expand

Commit Message

Jonathan Cameron May 8, 2022, 5:55 p.m. UTC 
From: Jonathan Cameron <Jonathan.Cameron@huawei.com>

____cacheline_aligned is insufficient guarantee for non-coherent DMA.
Switch to the updated IIO_DMA_MINALIGN definition.

Update comment to reflect that DMA safety may require separate
cachelines.

Fixes: cbab791c5e2a5 ("iio: accel: add ADXL367 driver")
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Cosmin Tanislav <demonsingur@gmail.com>
Acked-by: Nuno Sá <nuno.sa@analog.com>
---
 drivers/iio/accel/adxl367.c     | 2 +-
 drivers/iio/accel/adxl367_spi.c | 8 +++++---
 2 files changed, 6 insertions(+), 4 deletions(-)
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Patch

diff --git a/drivers/iio/accel/adxl367.c b/drivers/iio/accel/adxl367.c
index 62960134ea19..d680bec05efc 100644
--- a/drivers/iio/accel/adxl367.c
+++ b/drivers/iio/accel/adxl367.c
@@ -179,7 +179,7 @@  struct adxl367_state {
 	unsigned int	fifo_set_size;
 	unsigned int	fifo_watermark;
 
-	__be16		fifo_buf[ADXL367_FIFO_SIZE] ____cacheline_aligned;
+	__be16		fifo_buf[ADXL367_FIFO_SIZE] __aligned(IIO_DMA_MINALIGN);
 	__be16		sample_buf;
 	u8		act_threshold_buf[2];
 	u8		inact_time_buf[2];
diff --git a/drivers/iio/accel/adxl367_spi.c b/drivers/iio/accel/adxl367_spi.c
index 26dfc821ebbe..118c894015a5 100644
--- a/drivers/iio/accel/adxl367_spi.c
+++ b/drivers/iio/accel/adxl367_spi.c
@@ -9,6 +9,8 @@ 
 #include <linux/regmap.h>
 #include <linux/spi/spi.h>
 
+#include <linux/iio/iio.h>
+
 #include "adxl367.h"
 
 #define ADXL367_SPI_WRITE_COMMAND	0x0A
@@ -28,10 +30,10 @@  struct adxl367_spi_state {
 	struct spi_transfer	fifo_xfer[2];
 
 	/*
-	 * DMA (thus cache coherency maintenance) requires the
-	 * transfer buffers to live in their own cache lines.
+	 * DMA (thus cache coherency maintenance) may require the
+	 * transfer buffers live in their own cache lines.
 	 */
-	u8			reg_write_tx_buf[1] ____cacheline_aligned;
+	u8			reg_write_tx_buf[1] __aligned(IIO_DMA_MINALIGN);
 	u8			reg_read_tx_buf[2];
 	u8			fifo_tx_buf[1];
 };