| Message ID | 20240117-dev_sigma_delta_no_irq_flags-v1-1-db39261592cf@analog.com (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
| Series | iio: adc: ad_sigma_delta: misc fixes/improvements | expand |
On Wed, 17 Jan 2024 13:41:03 +0100 Nuno Sa <nuno.sa@analog.com> wrote: > Aligning the buffer to the L1 cache is not sufficient in some platforms > as they might have larger cacheline sizes for caches after L1 and thus, > we can't guarantee DMA safety. > > That was the whole reason to introduce IIO_DMA_MINALIGN in [1]. Do the same > for the sigma_delta ADCs. > > [1]: https://lore.kernel.org/linux-iio/20220508175712.647246-2-jic23@kernel.org/ > Fixes: 0fb6ee8d0b5e ("iio: ad_sigma_delta: Don't put SPI transfer buffer on the stack") > Signed-off-by: Nuno Sa <nuno.sa@analog.com> Applied to the fixes-togreg branch of iio.git and marked for stable. Thanks, Jonathan > --- > include/linux/iio/adc/ad_sigma_delta.h | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/include/linux/iio/adc/ad_sigma_delta.h b/include/linux/iio/adc/ad_sigma_delta.h > index 7852f6c9a714..719cf9cc6e1a 100644 > --- a/include/linux/iio/adc/ad_sigma_delta.h > +++ b/include/linux/iio/adc/ad_sigma_delta.h > @@ -8,6 +8,8 @@ > #ifndef __AD_SIGMA_DELTA_H__ > #define __AD_SIGMA_DELTA_H__ > > +#include <linux/iio/iio.h> > + > enum ad_sigma_delta_mode { > AD_SD_MODE_CONTINUOUS = 0, > AD_SD_MODE_SINGLE = 1, > @@ -99,7 +101,7 @@ struct ad_sigma_delta { > * 'rx_buf' is up to 32 bits per sample + 64 bit timestamp, > * rounded to 16 bytes to take into account padding. > */ > - uint8_t tx_buf[4] ____cacheline_aligned; > + uint8_t tx_buf[4] __aligned(IIO_DMA_MINALIGN); > uint8_t rx_buf[16] __aligned(8); > }; > >
diff --git a/include/linux/iio/adc/ad_sigma_delta.h b/include/linux/iio/adc/ad_sigma_delta.h index 7852f6c9a714..719cf9cc6e1a 100644 --- a/include/linux/iio/adc/ad_sigma_delta.h +++ b/include/linux/iio/adc/ad_sigma_delta.h @@ -8,6 +8,8 @@ #ifndef __AD_SIGMA_DELTA_H__ #define __AD_SIGMA_DELTA_H__ +#include <linux/iio/iio.h> + enum ad_sigma_delta_mode { AD_SD_MODE_CONTINUOUS = 0, AD_SD_MODE_SINGLE = 1, @@ -99,7 +101,7 @@ struct ad_sigma_delta { * 'rx_buf' is up to 32 bits per sample + 64 bit timestamp, * rounded to 16 bytes to take into account padding. */ - uint8_t tx_buf[4] ____cacheline_aligned; + uint8_t tx_buf[4] __aligned(IIO_DMA_MINALIGN); uint8_t rx_buf[16] __aligned(8); };
Aligning the buffer to the L1 cache is not sufficient in some platforms as they might have larger cacheline sizes for caches after L1 and thus, we can't guarantee DMA safety. That was the whole reason to introduce IIO_DMA_MINALIGN in [1]. Do the same for the sigma_delta ADCs. [1]: https://lore.kernel.org/linux-iio/20220508175712.647246-2-jic23@kernel.org/ Fixes: 0fb6ee8d0b5e ("iio: ad_sigma_delta: Don't put SPI transfer buffer on the stack") Signed-off-by: Nuno Sa <nuno.sa@analog.com> --- include/linux/iio/adc/ad_sigma_delta.h | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)