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[64/92] iio: dac: ti-dac7612: Fix alignment for DMA safety

Message ID 20220503085935.1533814-65-jic23@kernel.org (mailing list archive)
State Superseded
Headers show
Series IIO: Fix alignment of buffers for DMA | expand

Commit Message

Jonathan Cameron May 3, 2022, 8:59 a.m. UTC
From: Jonathan Cameron <Jonathan.Cameron@huawei.com>

____cacheline_aligned is an insufficient guarantee for non-coherent DMA
on platforms with 128 byte cachelines above L1.  Switch to the updated
IIO_ALIGN definition.

Updated help text to 'may' require buffers to be in their own cacheline.

Fixes: 977724d20584 ("iio:dac:ti-dac7612: Add driver for Texas Instruments DAC7612")
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Ricardo Ribalda <ribalda@kernel.org>
---
 drivers/iio/dac/ti-dac7612.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Comments

Ricardo Ribalda Delgado May 3, 2022, 11:10 a.m. UTC | #1
On Tue, May 3, 2022 at 11:01 AM Jonathan Cameron <jic23@kernel.org> wrote:
>
> From: Jonathan Cameron <Jonathan.Cameron@huawei.com>
>
> ____cacheline_aligned is an insufficient guarantee for non-coherent DMA
> on platforms with 128 byte cachelines above L1.  Switch to the updated
> IIO_ALIGN definition.
>
> Updated help text to 'may' require buffers to be in their own cacheline.
>
> Fixes: 977724d20584 ("iio:dac:ti-dac7612: Add driver for Texas Instruments DAC7612")
> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Ricardo Ribalda <ribalda@chromium.org>
> Cc: Ricardo Ribalda <ribalda@kernel.org>
> ---
>  drivers/iio/dac/ti-dac7612.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/iio/dac/ti-dac7612.c b/drivers/iio/dac/ti-dac7612.c
> index 4c0f4b5e9ff4..d118df004539 100644
> --- a/drivers/iio/dac/ti-dac7612.c
> +++ b/drivers/iio/dac/ti-dac7612.c
> @@ -31,10 +31,10 @@ struct dac7612 {
>         struct mutex lock;
>
>         /*
> -        * DMA (thus cache coherency maintenance) requires the
> +        * DMA (thus cache coherency maintenance) may require the
>          * transfer buffers to live in their own cache lines.
>          */
> -       uint8_t data[2] ____cacheline_aligned;
> +       uint8_t data[2] __aligned(IIO_ALIGN);
>  };
>
>  static int dac7612_cmd_single(struct dac7612 *priv, int channel, u16 val)
> --
> 2.36.0
>
diff mbox series

Patch

diff --git a/drivers/iio/dac/ti-dac7612.c b/drivers/iio/dac/ti-dac7612.c
index 4c0f4b5e9ff4..d118df004539 100644
--- a/drivers/iio/dac/ti-dac7612.c
+++ b/drivers/iio/dac/ti-dac7612.c
@@ -31,10 +31,10 @@  struct dac7612 {
 	struct mutex lock;
 
 	/*
-	 * DMA (thus cache coherency maintenance) requires the
+	 * DMA (thus cache coherency maintenance) may require the
 	 * transfer buffers to live in their own cache lines.
 	 */
-	uint8_t data[2] ____cacheline_aligned;
+	uint8_t data[2] __aligned(IIO_ALIGN);
 };
 
 static int dac7612_cmd_single(struct dac7612 *priv, int channel, u16 val)