This is a note to let you know that I've just added the patch titled
iio: adc: ad7887: 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-ad7887-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 86da99d7d2c796864db0505ef8afa01182ffdc07
Author: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
Date: Sun May 8 18:55:57 2022 +0100
iio: adc: ad7887: Fix alignment for DMA safety
[ Upstream commit b330ea6bc52468e183ced79189ff064f36c64aa7 ]
____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 tag is clearly not where this was introduced but it is very unlikely
anyone will back port it past that point.
Fixes: 65dd3d3d7a9b ("staging:iio:ad7887: Squash everything into one file")
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
Cc: Lars-Peter Clausen <lars@xxxxxxxxxx>
Acked-by: Nuno Sá <nuno.sa@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20220508175712.647246-18-jic23@xxxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/iio/adc/ad7887.c b/drivers/iio/adc/ad7887.c
index f64999714a4d..965bdc8aa696 100644
--- a/drivers/iio/adc/ad7887.c
+++ b/drivers/iio/adc/ad7887.c
@@ -66,13 +66,12 @@ struct ad7887_state {
unsigned char tx_cmd_buf[4];
/*
- * DMA (thus cache coherency maintenance) requires the
+ * DMA (thus cache coherency maintenance) may require the
* transfer buffers to live in their own cache lines.
* Buffer needs to be large enough to hold two 16 bit samples and a
* 64 bit aligned 64 bit timestamp.
*/
- unsigned char data[ALIGN(4, sizeof(s64)) + sizeof(s64)]
- ____cacheline_aligned;
+ unsigned char data[ALIGN(4, sizeof(s64)) + sizeof(s64)] __aligned(IIO_DMA_MINALIGN);
};
enum ad7887_supported_device_ids {
