[PATCH] mmc: mtk-sd: implement waiting for DAT0 line state

[Jaehoon Chung]

On 11/5/21 10:34 PM, Julien Masson wrote:
> With the recent changes on mmc driver, we saw that the boot is ~5 secs
> longer compared to v2021.07 on mediatek platforms.
> 
> This regression is seen during mmc_init and caused by the following
> patch [1].
> 
> Indeed since we did not support poll dat0, we fulfilled the condition
> of [1] and a delay of 500 ms was added for every __mmc_switch call.
> 
> By adding the support of wait_dat0(), we now don't need to mdelay
> during mmc_init anymore.
> 
> [1]: https://protect2.fireeye.com/v1/url?k=553fefc7-0aa4d6e8-553e6488-0cc47a31cdf8-658c3df5220dc893&q=1&e=badb6c30-0546-4072-80c5-a772143bc5ee&u=https%3A%2F%2Fpatchwork.ozlabs.org%2Fproject%2Fuboot%2Fpatch%2F1629192034-64056-1-git-send-email-ye.li%40nxp.com%2F
> 
> Signed-off-by: Julien Masson <jmasson at baylibre.com>

Reviewed-by: Jaehoon Chung <jh80.chung at samsung.com>

Best Regards,
Jaehoon Chung

> ---
>  drivers/mmc/mtk-sd.c | 15 +++++++++++++++
>  1 file changed, 15 insertions(+)
> 
> diff --git a/drivers/mmc/mtk-sd.c b/drivers/mmc/mtk-sd.c
> index 8599f095bc..97182ffd7f 100644
> --- a/drivers/mmc/mtk-sd.c
> +++ b/drivers/mmc/mtk-sd.c
> @@ -1724,6 +1724,20 @@ static int msdc_drv_bind(struct udevice *dev)
>  	return mmc_bind(dev, &plat->mmc, &plat->cfg);
>  }
>  
> +static int msdc_ops_wait_dat0(struct udevice *dev, int state, int timeout_us)
> +{
> +	struct msdc_host *host = dev_get_priv(dev);
> +	int ret;
> +	u32 reg;
> +
> +	ret = readl_poll_sleep_timeout(&host->base->msdc_ps, reg,
> +				       !!(reg & MSDC_PS_DAT0) == !!state,
> +				       1000, /* 1 ms */
> +				       timeout_us);
> +
> +	return ret;
> +}
> +
>  static const struct dm_mmc_ops msdc_ops = {
>  	.send_cmd = msdc_ops_send_cmd,
>  	.set_ios = msdc_ops_set_ios,
> @@ -1732,6 +1746,7 @@ static const struct dm_mmc_ops msdc_ops = {
>  #ifdef MMC_SUPPORTS_TUNING
>  	.execute_tuning = msdc_execute_tuning,
>  #endif
> +	.wait_dat0 = msdc_ops_wait_dat0,
>  };
>  
>  static const struct msdc_compatible mt7620_compat = {
>