This is a note to let you know that I've just added the patch titled
spi: sun6i: reduce DMA RX transfer width to single byte
to the 5.15-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:
spi-sun6i-reduce-dma-rx-transfer-width-to-single-byt.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit fcd1265b8f0061413801fe594bc9fe93399c8253
Author: Tobias Schramm <t.schramm@xxxxxxxxxxx>
Date: Sun Aug 27 17:25:57 2023 +0200
spi: sun6i: reduce DMA RX transfer width to single byte
[ Upstream commit 171f8a49f212e87a8b04087568e1b3d132e36a18 ]
Through empirical testing it has been determined that sometimes RX SPI
transfers with DMA enabled return corrupted data. This is down to single
or even multiple bytes lost during DMA transfer from SPI peripheral to
memory. It seems the RX FIFO within the SPI peripheral can become
confused when performing bus read accesses wider than a single byte to it
during an active SPI transfer.
This patch reduces the width of individual DMA read accesses to the
RX FIFO to a single byte to mitigate that issue.
Signed-off-by: Tobias Schramm <t.schramm@xxxxxxxxxxx>
Link: https://lore.kernel.org/r/20230827152558.5368-2-t.schramm@xxxxxxxxxxx
Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/spi/spi-sun6i.c b/drivers/spi/spi-sun6i.c
index 23ad052528dbe..2bfe87873edb3 100644
--- a/drivers/spi/spi-sun6i.c
+++ b/drivers/spi/spi-sun6i.c
@@ -200,7 +200,7 @@ static int sun6i_spi_prepare_dma(struct sun6i_spi *sspi,
struct dma_slave_config rxconf = {
.direction = DMA_DEV_TO_MEM,
.src_addr = sspi->dma_addr_rx,
- .src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES,
+ .src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE,
.src_maxburst = 8,
};
