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[v2,22/92] iio: adc: ltc2497: Fix alignment for DMA safety

Message ID 20220508175712.647246-23-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, 5:56 p.m. UTC 
From: Jonathan Cameron <Jonathan.Cameron@huawei.com>

____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: bc82222fcca1 ("iio:adc: Driver for Linear Technology LTC2497 ADC")
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Michael Hennerich <michael.hennerich@analog.com>
Acked-by: Nuno Sá <nuno.sa@analog.com>
---
 drivers/iio/adc/ltc2497.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
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Patch

diff --git a/drivers/iio/adc/ltc2497.c b/drivers/iio/adc/ltc2497.c
index 1adddf5a88a9..f7c786f37ceb 100644
--- a/drivers/iio/adc/ltc2497.c
+++ b/drivers/iio/adc/ltc2497.c
@@ -20,10 +20,10 @@  struct ltc2497_driverdata {
 	struct ltc2497core_driverdata common_ddata;
 	struct i2c_client *client;
 	/*
-	 * DMA (thus cache coherency maintenance) requires the
+	 * DMA (thus cache coherency maintenance) may require the
 	 * transfer buffers to live in their own cache lines.
 	 */
-	__be32 buf ____cacheline_aligned;
+	__be32 buf __aligned(IIO_DMA_MINALIGN);
 };
 
 static int ltc2497_result_and_measure(struct ltc2497core_driverdata *ddata,