Re: [PATCH v2 3/3] mmc: sdhci-esdhc-imx: only enable DAT[0] and CMD line auto tuning for SDIO device

[Adrian Hunter <adrian.hunter@intel.com>]

On 21/12/22 13:28, haibo.chen@nxp.com wrote:
> From: Haibo Chen <haibo.chen@nxp.com>
> 
> USDHC IP has one limitation: the tuning circuit can't handle the async
> sdio device interrupt correctly. When sdio device use 4 data lines,
> async sdio interrupt will use the shared DAT[1], if enable auto tuning
> circuit to check these 4 data lines, include the DAT[1], this circuit
> will detect this interrupt, take this as data on DAT[1], and adjust the
> delay cell wrongly, finally will cause the DATA/CMD CRC error.
> So for SDIO device, only enable DAT[0] and CMD line for auto tuning.
> 
> Signed-off-by: Haibo Chen <haibo.chen@nxp.com>
> ---
>  drivers/mmc/host/sdhci-esdhc-imx.c | 14 ++++++++++++++
>  1 file changed, 14 insertions(+)
> 
> diff --git a/drivers/mmc/host/sdhci-esdhc-imx.c b/drivers/mmc/host/sdhci-esdhc-imx.c
> index bf8d6f60a9ee..d6ce4c8d23dc 100644
> --- a/drivers/mmc/host/sdhci-esdhc-imx.c
> +++ b/drivers/mmc/host/sdhci-esdhc-imx.c
> @@ -448,6 +448,20 @@ static inline void usdhc_auto_tuning_mode_sel_and_en(struct sdhci_host *host)
>  		break;
>  	}
>  
> +	/*
> +	 * For USDHC, auto tuning circuit can not handle the async sdio
> +	 * device interrupt correctly. When sdio device use 4 data lines,
> +	 * async sdio interrupt will use the shared DAT[1], if enable auto
> +	 * tuning circuit check these 4 data lines, include the DAT[1],
> +	 * this circuit will detect this interrupt, take this as a data on
> +	 * DAT[1], and adjust the delay cell wrongly.
> +	 * This is the hardware design limitation, to avoid this, for sdio
> +	 * device, config the auto tuning circuit only check DAT[0] and CMD
> +	 * line.
> +	 */
> +	if (!host->mmc->card && mmc_card_sdio(host->mmc->card))

Looks like !host->mmc->card should be host->mmc->card

> +		auto_tune_buswidth = ESDHC_VEND_SPEC2_AUTO_TUNE_1BIT_EN;
> +
>  	esdhc_clrset_le(host, ESDHC_VEND_SPEC2_AUTO_TUNE_MODE_MASK,
>  			auto_tune_buswidth | ESDHC_VEND_SPEC2_AUTO_TUNE_CMD_EN,
>  			ESDHC_VEND_SPEC2);