This is a note to let you know that I've just added the patch titled
iio: adc: ltc2496: Fix alignment for DMA safety
to the 5.18-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
iio-adc-ltc2496-fix-alignment-for-dma-safety.patch
and it can be found in the queue-5.18 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 5bd7209d2fb3cbb5181b751f6aae185a73095eb7
Author: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
Date: Sun May 8 18:56:01 2022 +0100
iio: adc: ltc2496: Fix alignment for DMA safety
[ Upstream commit 1673b7ca2dc1fb3b8d7c94a112496c02d34ae449 ]
____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: e4c5c4dfaa88 ("iio: adc: new driver to support Linear technology's ltc2496")
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
Cc: Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx>
Acked-by: Nuno Sá <nuno.sa@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20220508175712.647246-22-jic23@xxxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/iio/adc/ltc2496.c b/drivers/iio/adc/ltc2496.c
index 5a55f79f2574..dfb3bb5997e5 100644
--- a/drivers/iio/adc/ltc2496.c
+++ b/drivers/iio/adc/ltc2496.c
@@ -24,10 +24,10 @@ struct ltc2496_driverdata {
struct spi_device *spi;
/*
- * DMA (thus cache coherency maintenance) requires the
+ * DMA (thus cache coherency maintenance) may require the
* transfer buffers to live in their own cache lines.
*/
- unsigned char rxbuf[3] ____cacheline_aligned;
+ unsigned char rxbuf[3] __aligned(IIO_DMA_MINALIGN);
unsigned char txbuf[3];
};
