This is a note to let you know that I've just added the patch titled
iio: adc: mcp320x: 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-mcp320x-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 683a0c84db3fff5764d904d3f6d1e222df569bb3
Author: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
Date: Sun May 8 18:56:07 2022 +0100
iio: adc: mcp320x: Fix alignment for DMA safety
[ Upstream commit e770f78036ce4327caf285873f4b20564a8b4f0f ]
____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.
Worth noting the fixes tag refers to the same issue being observed
on a platform that probably had only 64 byte cachelines.
Fixes: 0e81bc99a082 ("iio: mcp320x: Fix occasional incorrect readings")
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
Cc: Michael Welling <mwelling@xxxxxxxx>
Acked-by: Nuno Sá <nuno.sa@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20220508175712.647246-28-jic23@xxxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/iio/adc/mcp320x.c b/drivers/iio/adc/mcp320x.c
index b4c69acb33e3..f3b81798b3c9 100644
--- a/drivers/iio/adc/mcp320x.c
+++ b/drivers/iio/adc/mcp320x.c
@@ -92,7 +92,7 @@ struct mcp320x {
struct mutex lock;
const struct mcp320x_chip_info *chip_info;
- u8 tx_buf ____cacheline_aligned;
+ u8 tx_buf __aligned(IIO_DMA_MINALIGN);
u8 rx_buf[4];
};
