[PATCH v2] mmc: sdhci-esdhc-imx: wait for data transfer completion before reset

[Bough Chen]

> -----Original Message-----
> From: Luke Wang <ziniu.wang_1 at nxp.com>
> Sent: 2025年12月5日 15:17
> To: adrian.hunter at intel.com; Bough Chen <haibo.chen at nxp.com>;
> ulf.hansson at linaro.org
> Cc: shawnguo at kernel.org; s.hauer at pengutronix.de; kernel at pengutronix.de;
> festevam at gmail.com; linux-mmc at vger.kernel.org; imx at lists.linux.dev; dl-S32
> <S32 at nxp.com>; linux-arm-kernel at lists.infradead.org;
> linux-kernel at vger.kernel.org
> Subject: [PATCH v2] mmc: sdhci-esdhc-imx: wait for data transfer completion
> before reset
> 
> From: Luke Wang <ziniu.wang_1 at nxp.com>
> 
> On IMX7ULP platforms, certain SD cards (e.g. Kingston Canvas Go! Plus) cause
> system hangs and reboots during manual tuning. These cards exhibit large gaps
> (~16us) between tuning command response and data transmission.
> When cmd CRC errors occur during tuning, the code assumes data errors even
> tuning data hasn't been fully received and then reset host data circuit.
> 
> Per IMX7ULP reference manual, reset operations (RESET_DATA/ALL) need to
> make sure no active data transfers. Previously, resetting while data was in-flight
> would clear data circuit, including ADMA/SDMA address, causing data to be
> transmitted to incorrect memory address. This patch adds polling for data
> transfer completion before executing resets.
> 
> Signed-off-by: Luke Wang <ziniu.wang_1 at nxp.com>
> ---
> v2: amend commit message
> ---
>  drivers/mmc/host/sdhci-esdhc-imx.c | 15 +++++++++++++++
>  1 file changed, 15 insertions(+)
> 
> diff --git a/drivers/mmc/host/sdhci-esdhc-imx.c
> b/drivers/mmc/host/sdhci-esdhc-imx.c
> index a7a5df673b0f..affde1936510 100644
> --- a/drivers/mmc/host/sdhci-esdhc-imx.c
> +++ b/drivers/mmc/host/sdhci-esdhc-imx.c
> @@ -1453,6 +1453,21 @@ static void esdhc_set_uhs_signaling(struct
> sdhci_host *host, unsigned timing)
> 
>  static void esdhc_reset(struct sdhci_host *host, u8 mask)  {
> +	u32 present_state;
> +	int ret;
> +
> +	/*
> +	 * For data or full reset, ensure any active data transfer completes
> +	 * before resetting to avoid system hang.
> +	 */
> +	if (mask & (SDHCI_RESET_DATA | SDHCI_RESET_ALL)) {
> +		ret = readl_poll_timeout_atomic(host->ioaddr + ESDHC_PRSSTAT,
> present_state,

I'm okay with the patch, but I find one thing here:

I notice you use _atomic here, I guess you want to cover the case when the reset function is called in hardware irq handler sdhci_irq().
I'm not sure whether it is suitable to add delay in hardware iqr handler, I find there is also udelay in sdhci_reset(), sdhci_reset can also be called in hardware irq handler when there is cmd_crc/data_crc error.
Adrian/Ulf, do you notice this issue before? Any comments?

Regards
Haibo Chen


> +						!(present_state & SDHCI_DATA_INHIBIT), 2,
> 100000);
> +		if (ret == -ETIMEDOUT)
> +			dev_warn(mmc_dev(host->mmc),
> +				 "timeout waiting for data transfer completion\n");
> +	}
> +
>  	sdhci_and_cqhci_reset(host, mask);
> 
>  	sdhci_writel(host, host->ier, SDHCI_INT_ENABLE);
> --
> 2.34.1