Re: [PATCH v7 RESEND 07/13] spi: imx: fix ERR009165

[Sascha Hauer]

On Tue, May 12, 2020 at 01:32:30AM +0800, Robin Gong wrote:
> Change to XCH  mode even in dma mode, please refer to the below
> errata:
> https://www.nxp.com/docs/en/errata/IMX6DQCE.pdf
> 
> Signed-off-by: Robin Gong <yibin.gong@xxxxxxx>
> Acked-by: Mark Brown <broonie@xxxxxxxxxx>
> ---
>  drivers/spi/spi-imx.c | 16 ++++++++--------
>  1 file changed, 8 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/spi/spi-imx.c b/drivers/spi/spi-imx.c
> index f4f28a4..70df8e6 100644
> --- a/drivers/spi/spi-imx.c
> +++ b/drivers/spi/spi-imx.c
> @@ -585,8 +585,8 @@ static int mx51_ecspi_prepare_transfer(struct spi_imx_data *spi_imx,
>  	ctrl |= mx51_ecspi_clkdiv(spi_imx, t->speed_hz, &clk);
>  	spi_imx->spi_bus_clk = clk;
>  
> -	if (spi_imx->usedma)
> -		ctrl |= MX51_ECSPI_CTRL_SMC;
> +	/* ERR009165: work in XHC mode as PIO */
> +	ctrl &= ~MX51_ECSPI_CTRL_SMC;
>  
>  	writel(ctrl, spi_imx->base + MX51_ECSPI_CTRL);
>  
> @@ -617,7 +617,7 @@ static void mx51_setup_wml(struct spi_imx_data *spi_imx)
>  	 * and enable DMA request.
>  	 */
>  	writel(MX51_ECSPI_DMA_RX_WML(spi_imx->wml - 1) |
> -		MX51_ECSPI_DMA_TX_WML(spi_imx->wml) |
> +		MX51_ECSPI_DMA_TX_WML(0) |
>  		MX51_ECSPI_DMA_RXT_WML(spi_imx->wml) |
>  		MX51_ECSPI_DMA_TEDEN | MX51_ECSPI_DMA_RXDEN |
>  		MX51_ECSPI_DMA_RXTDEN, spi_imx->base + MX51_ECSPI_DMA);
> @@ -1171,7 +1171,11 @@ static int spi_imx_dma_configure(struct spi_master *master)
>  	tx.direction = DMA_MEM_TO_DEV;
>  	tx.dst_addr = spi_imx->base_phys + MXC_CSPITXDATA;
>  	tx.dst_addr_width = buswidth;
> -	tx.dst_maxburst = spi_imx->wml;
> +	/*
> +	 * For ERR009165 with tx_wml = 0 could enlarge burst size to fifo size
> +	 * to speed up fifo filling as possible.
> +	 */
> +	tx.dst_maxburst = spi_imx->devtype_data->fifo_size;

In the next patch this is changed again to:

+       if (spi_imx->devtype_data->tx_glitch_fixed)
+               tx.dst_maxburst = spi_imx->wml;
+       else
+               tx.dst_maxburst = spi_imx->devtype_data->fifo_size;

So with tx_glitch_fixed we end up with tx.dst_maxburst being the same
as two patches before which is rather confusing. Better introduce
tx_glitch_fixed in this patch, or maybe even merge this patch and the
next one.

Sascha

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