Re: [PATCH] spi: omap2-mcspi: Fix DMA and FIFO event trigger size mismatch

[David Lechner]

On 1/15/19 12:58 AM, Vignesh R wrote:
> Commit b682cffa3ac6 ("spi: omap2-mcspi: Set FIFO DMA trigger level to word length")
> broke SPI transfers where bits_per_word != 8. This is because of
> mimsatch between McSPI FIFO level event trigger size (SPI word length) and
> DMA request size(word length * maxburst). This leads to data
> corruption, lockup and errors like:
>
> 	spi1.0: EOW timed out
>
> Fix this by setting DMA maxburst size to 1 so that
> McSPI FIFO level event trigger size matches DMA request size.
>
> Fixes: b682cffa3ac6 ("spi: omap2-mcspi: Set FIFO DMA trigger level to word length")
> Cc: stable@xxxxxxxxxxxxxxx
> Reported-by: David Lechner <david@xxxxxxxxxxxxxx>
> Tested-by: David Lechner <david@xxxxxxxxxxxxxx>
> Signed-off-by: Vignesh R <vigneshr@xxxxxx>
> ---
>   drivers/spi/spi-omap2-mcspi.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/spi/spi-omap2-mcspi.c b/drivers/spi/spi-omap2-mcspi.c
> index 2fd8881fcd65..8be304379628 100644
> --- a/drivers/spi/spi-omap2-mcspi.c
> +++ b/drivers/spi/spi-omap2-mcspi.c
> @@ -623,8 +623,8 @@ omap2_mcspi_txrx_dma(struct spi_device *spi, struct spi_transfer *xfer)
>   	cfg.dst_addr = cs->phys + OMAP2_MCSPI_TX0;
>   	cfg.src_addr_width = width;
>   	cfg.dst_addr_width = width;
> -	cfg.src_maxburst = es;
> -	cfg.dst_maxburst = es;
> +	cfg.src_maxburst = 1;
> +	cfg.dst_maxburst = 1;
>   
>   	rx = xfer->rx_buf;
>   	tx = xfer->tx_buf;

Works for me.