[PATCH 5.19 0693/1157] iio: dac: ti-dac7612: Fix alignment for DMA safety

Greg Kroah-Hartman
2022-08-16T04:39:19Z

From: Jonathan Cameron <Jonathan.Cameron@huawei.com>

[ Upstream commit b9ac08b3282a95fcefb057c2886028a6807725d8 ]

____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.

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>
Acked-by: Nuno Sá <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20220508175712.647246-65-jic23@kernel.org
Signed-off-by: Sasha Levin <sashal@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..8195815de26f 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_DMA_MINALIGN);
};

static int dac7612_cmd_single(struct dac7612 *priv, int channel, u16 val)
--
2.35.1