On 10/02/20 10:49 am, haibo.chen@xxxxxxx wrote:
> From: Haibo Chen <haibo.chen@xxxxxxx>
>
> Currently, when use standard tuning, driver default disable DMA just before
> send tuning command. But on i.MX8 usdhc, this is not enough. Need also clear
> DMA_SEL. If not, once the DMA_SEL select AMDA2 before, even dma already disabled,
> when send tuning command, usdhc will still prefetch the ADMA script from wrong
> DMA address, then we will see IOMMU report some error which show lack of TLB
> mapping.
>
> Signed-off-by: Haibo Chen <haibo.chen@xxxxxxx>
Acked-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
> ---
> drivers/mmc/host/sdhci-esdhc-imx.c | 18 ++++++++++++++++--
> 1 file changed, 16 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/mmc/host/sdhci-esdhc-imx.c b/drivers/mmc/host/sdhci-esdhc-imx.c
> index dedc067cd0dd..44837e3014e8 100644
> --- a/drivers/mmc/host/sdhci-esdhc-imx.c
> +++ b/drivers/mmc/host/sdhci-esdhc-imx.c
> @@ -639,10 +639,24 @@ static void esdhc_writew_le(struct sdhci_host *host, u16 val, int reg)
> * For DMA access restore the levels to default value.
> */
> m = readl(host->ioaddr + ESDHC_WTMK_LVL);
> - if (val & SDHCI_TRNS_DMA)
> + if (val & SDHCI_TRNS_DMA) {
> wml = ESDHC_WTMK_LVL_WML_VAL_DEF;
> - else
> + } else {
> + u8 ctrl;
> wml = ESDHC_WTMK_LVL_WML_VAL_MAX;
> +
> + /*
> + * Since already disable DMA mode, so also need
> + * to clear the DMASEL. Otherwise, for standard
> + * tuning, when send tuning command, usdhc will
> + * still prefetch the ADMA script from wrong
> + * DMA address, then we will see IOMMU report
> + * some error which show lack of TLB mapping.
> + */
> + ctrl = sdhci_readb(host, SDHCI_HOST_CONTROL);
> + ctrl &= ~SDHCI_CTRL_DMA_MASK;
> + sdhci_writeb(host, ctrl, SDHCI_HOST_CONTROL);
> + }
> m &= ~(ESDHC_WTMK_LVL_RD_WML_MASK |
> ESDHC_WTMK_LVL_WR_WML_MASK);
> m |= (wml << ESDHC_WTMK_LVL_RD_WML_SHIFT) |
>
