Re: [PATCH v4 2/7] mmc: sdhci-esdhc-imx: restore DLL override for DDR modes on resume

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

On 03/07/2026 13:42, ziniu.wang_1@oss.nxp.com wrote:
> From: Luke Wang <ziniu.wang_1@nxp.com>
> 
> sdhci_esdhc_imx_hwinit() unconditionally clears ESDHC_DLL_CTRL by
> writing zero. For SDIO devices that keep power during system suspend
> and operate in DDR mode, the card remains in DDR timing while the host
> DLL override configuration is lost.
> 
> Extract the DLL override setup from esdhc_set_uhs_signaling() into
> a helper esdhc_set_dll_override(), and call it on the resume path
> when the card kept power and is using a DDR timing mode.
> 
> Fixes: 676a83855614 ("mmc: host: sdhci-esdhc-imx: refactor the system PM logic")
> Reviewed-by: Frank Li <Frank.Li@nxp.com>
> Reviewed-by: Haibo Chen <haibo.chen@nxp.com>
> Signed-off-by: Luke Wang <ziniu.wang_1@nxp.com>

Acked-by: Adrian Hunter <adrian.hunter@intel.com>

> ---
>  drivers/mmc/host/sdhci-esdhc-imx.c | 39 +++++++++++++++++++++---------
>  1 file changed, 28 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/mmc/host/sdhci-esdhc-imx.c b/drivers/mmc/host/sdhci-esdhc-imx.c
> index 6526d65538de..7230d70e02ae 100644
> --- a/drivers/mmc/host/sdhci-esdhc-imx.c
> +++ b/drivers/mmc/host/sdhci-esdhc-imx.c
> @@ -1349,6 +1349,23 @@ static int esdhc_change_pinstate(struct sdhci_host *host,
>  	return pinctrl_select_state(imx_data->pinctrl, pinctrl);
>  }
>  
> +static void esdhc_set_dll_override(struct sdhci_host *host)
> +{
> +	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
> +	struct pltfm_imx_data *imx_data = sdhci_pltfm_priv(pltfm_host);
> +	struct esdhc_platform_data *boarddata = &imx_data->boarddata;
> +	u32 v;
> +
> +	if (!boarddata->delay_line)
> +		return;
> +
> +	v = boarddata->delay_line << ESDHC_DLL_OVERRIDE_VAL_SHIFT |
> +	    (1 << ESDHC_DLL_OVERRIDE_EN_SHIFT);
> +	if (is_imx53_esdhc(imx_data))
> +		v <<= 1;
> +	writel(v, host->ioaddr + ESDHC_DLL_CTRL);
> +}
> +
>  /*
>   * For HS400 eMMC, there is a data_strobe line. This signal is generated
>   * by the device and used for data output and CRC status response output
> @@ -1404,7 +1421,6 @@ static void esdhc_set_uhs_signaling(struct sdhci_host *host, unsigned timing)
>  	u32 m;
>  	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
>  	struct pltfm_imx_data *imx_data = sdhci_pltfm_priv(pltfm_host);
> -	struct esdhc_platform_data *boarddata = &imx_data->boarddata;
>  
>  	/* disable ddr mode and disable HS400 mode */
>  	m = readl(host->ioaddr + ESDHC_MIX_CTRL);
> @@ -1425,15 +1441,7 @@ static void esdhc_set_uhs_signaling(struct sdhci_host *host, unsigned timing)
>  		m |= ESDHC_MIX_CTRL_DDREN;
>  		writel(m, host->ioaddr + ESDHC_MIX_CTRL);
>  		imx_data->is_ddr = 1;
> -		if (boarddata->delay_line) {
> -			u32 v;
> -			v = boarddata->delay_line <<
> -				ESDHC_DLL_OVERRIDE_VAL_SHIFT |
> -				(1 << ESDHC_DLL_OVERRIDE_EN_SHIFT);
> -			if (is_imx53_esdhc(imx_data))
> -				v <<= 1;
> -			writel(v, host->ioaddr + ESDHC_DLL_CTRL);
> -		}
> +		esdhc_set_dll_override(host);
>  		break;
>  	case MMC_TIMING_MMC_HS400:
>  		m |= ESDHC_MIX_CTRL_DDREN | ESDHC_MIX_CTRL_HS400_EN;
> @@ -2123,9 +2131,18 @@ static int sdhci_esdhc_resume(struct device *dev)
>  	 * restore the saved tuning delay value for the device which keep
>  	 * power during system PM.
>  	 */
> -	if (mmc_card_keep_power(host->mmc) && esdhc_is_usdhc(imx_data))
> +	if (mmc_card_keep_power(host->mmc) && esdhc_is_usdhc(imx_data)) {
>  		sdhc_esdhc_tuning_restore(host);
>  
> +		/*
> +		 * Restore DLL override for DDR modes. hwinit unconditionally
> +		 * clears ESDHC_DLL_CTRL, but the card is still in DDR mode.
> +		 */
> +		if (host->timing == MMC_TIMING_UHS_DDR50 ||
> +		    host->timing == MMC_TIMING_MMC_DDR52)
> +			esdhc_set_dll_override(host);
> +	}
> +
>  	pm_runtime_put_autosuspend(dev);
>  
>  	return ret;