[PATCH 1/2] mmc: fsl_esdhc_imx: Fix fsl_esdhc_wait_dat0

[sbabic@denx.de]

> According to Haibo Chen [1] - the current implementation mmc_wait_dat0,
> the second mmc_wait_dat0() in mmc_switch_voltage() always return timeout.
> This causes UHS cards to not properly initialize to their highest rate,
> and default back for high-speed mode.
> When reviewing [1] and comparing it to the linux driver, it appears
> that this function can be accomplished by turning off the clock,
> and waiting for the clock-standby bit to become active.
> [1] - https://lists.denx.de/pipermail/u-boot/2021-January/438644.html
> Reported-by: Tim Harvey <tharvey@gateworks.com>
> Signed-off-by: Adam Ford <aford173@gmail.com>
> diff --git a/drivers/mmc/fsl_esdhc_imx.c b/drivers/mmc/fsl_esdhc_imx.c
> index 4c06361bee..e5814232a2 100644
> --- a/drivers/mmc/fsl_esdhc_imx.c
> +++ b/drivers/mmc/fsl_esdhc_imx.c
> @@ -1684,9 +1684,15 @@ static int fsl_esdhc_wait_dat0(struct udevice *dev, int state,
>  	struct fsl_esdhc_priv *priv = dev_get_priv(dev);
>  	struct fsl_esdhc *regs = priv->esdhc_regs;
>  
> +	/*
> +	 * Clear the clock-enable and wait for the bit indicating it
> +	 * is in standby.
> +	 */
> +	esdhc_clrbits32(&regs->vendorspec, VENDORSPEC_CKEN);
>  	ret = readx_poll_timeout(esdhc_read32, &regs->prsstat, tmp,
> -				!!(tmp & PRSSTAT_DAT0) == !!state,
> +				(tmp & PRSSTAT_SDSTB),
>  				timeout_us);
> +
>  	return ret;
>  }
>  
Applied to u-boot-imx, master, thanks !

Best regards,
Stefano Babic

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