[PATCH v2] mmc: retry CMD1 in mmc_send_op_cond() until the eMMC is ready

[Peng Fan]

> Subject: [PATCH v2] mmc: retry CMD1 in mmc_send_op_cond() until the
> eMMC is ready
> 
> From: Haibo Chen <haibo.chen at nxp.com>
> 
> According to eMMC specification v5.1 section 6.4.3, we should issue
> CMD1 repeatedly in the idle state until the eMMC is ready even if
> mmc_send_op_cond() send CMD1 with argument = 0. Otherwise some
> eMMC devices seems to enter the inactive mode after
> mmc_complete_op_cond() issued CMD0 when the eMMC device is busy.
> 
> Signed-off-by: Haibo Chen <haibo.chen at nxp.com>
> ---
>  drivers/mmc/mmc.c | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c index
> 85762b82e0..475f75fc64 100644
> --- a/drivers/mmc/mmc.c
> +++ b/drivers/mmc/mmc.c
> @@ -662,12 +662,15 @@ static int mmc_send_op_cond_iter(struct mmc
> *mmc, int use_arg)  static int mmc_send_op_cond(struct mmc *mmc)  {
>  	int err, i;
> +	int timeout = 1000;
> +	uint start;
> 
>  	/* Some cards seem to need this */
>  	mmc_go_idle(mmc);
> 
> +	start = get_timer(0);
>   	/* Asking to the card its capabilities */
> -	for (i = 0; i < 2; i++) {
> +	for (i = 0; ; i++) {
>  		err = mmc_send_op_cond_iter(mmc, i != 0);
>  		if (err)
>  			return err;
> @@ -675,6 +678,10 @@ static int mmc_send_op_cond(struct mmc *mmc)
>  		/* exit if not busy (flag seems to be inverted) */
>  		if (mmc->ocr & OCR_BUSY)
>  			break;
> +
> +		if (get_timer(start) > timeout)
> +			return -ETIMEDOUT;
> +		udelay(100);

The Linux code use 10ms delay, but it should be fine here.

Reviewed-by: Peng Fan <peng.fan at nxp.com>

>  	}
>  	mmc->op_cond_pending = 1;
>  	return 0;
> --
> 2.17.1