diff options
author | David Lechner <dlechner@baylibre.com> | 2025-05-07 23:42:40 +0300 |
---|---|---|
committer | Jonathan Cameron <Jonathan.Cameron@huawei.com> | 2025-05-21 16:20:31 +0300 |
commit | fa19c303254bae5b8d105ecdc7d714d092f2adda (patch) | |
tree | 42cf5a2de112f882f61c78166f4a5bc39d1013a5 | |
parent | 666eae6c6dab46cb5023170651286c47a693f661 (diff) | |
download | linux-fa19c303254bae5b8d105ecdc7d714d092f2adda.tar.xz |
iio: make IIO_DMA_MINALIGN minimum of 8 bytes
Add a condition to ensure that IIO_DMA_MINALIGN is at least 8 bytes.
On some 32-bit architectures, IIO_DMA_MINALIGN is 4. In many cases,
drivers are using this alignment for buffers that include a 64-bit
timestamp that is used with iio_push_to_buffers_with_ts(), which expects
the timestamp to be aligned to 8 bytes. To handle this, we can just make
IIO_DMA_MINALIGN at least 8 bytes.
Reviewed-by: Nuno Sá <nuno.sa@analog.com>
Signed-off-by: David Lechner <dlechner@baylibre.com>
Link: https://patch.msgid.link/20250507-iio-introduce-iio_declare_buffer_with_ts-v6-1-4aee1b9f1b89@baylibre.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
-rw-r--r-- | include/linux/iio/iio.h | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/include/linux/iio/iio.h b/include/linux/iio/iio.h index 638cf2420fbd..a574f22398e4 100644 --- a/include/linux/iio/iio.h +++ b/include/linux/iio/iio.h @@ -10,6 +10,7 @@ #include <linux/device.h> #include <linux/cdev.h> #include <linux/compiler_types.h> +#include <linux/minmax.h> #include <linux/slab.h> #include <linux/iio/types.h> /* IIO TODO LIST */ @@ -775,8 +776,14 @@ static inline void *iio_device_get_drvdata(const struct iio_dev *indio_dev) * to in turn include IIO_DMA_MINALIGN'd elements such as buffers which * must not share cachelines with the rest of the structure, thus making * them safe for use with non-coherent DMA. + * + * A number of drivers also use this on buffers that include a 64-bit timestamp + * that is used with iio_push_to_buffer_with_ts(). Therefore, in the case where + * DMA alignment is not sufficient for proper timestamp alignment, we align to + * 8 bytes instead. */ -#define IIO_DMA_MINALIGN ARCH_DMA_MINALIGN +#define IIO_DMA_MINALIGN MAX(ARCH_DMA_MINALIGN, sizeof(s64)) + struct iio_dev *iio_device_alloc(struct device *parent, int sizeof_priv); /* The information at the returned address is guaranteed to be cacheline aligned */ |