Re: [PATCH 3/3] mmc: Checking BKOPS status prior to Suspend

[Shawn Lin <shawn.lin@rock-chips.com>]

On 2017/1/17 20:15, Uri Yanai wrote:
> If asked to do device Runtime Suspend while
> in BKOPS and auto BKOPS is enabled return –EBUSY
>

The commit msg isn't correct as the code just return -EBUSY
when the level of BKOPS is EXT_CSD_BKOPS_LEVEL_PM_SUSPEND.

And how do you decide that EXT_CSD_BKOPS_LEVEL_2 should be used.
 From the spec, it means "performance being impacted". It would be
good to know a bit details inside the eMMC firmware.

BTW, should we use EXT_CSD_BKOPS_LEVEL_2 directly since it looks
more strightforward?


> Change-Id: Ie4b38a32fe98179f0bca5b57edaaa47a02d0a389
> Signed-off-by: Uri Yanai <uri.yanai@sandisk.com>
> Signed-off-by: Alex Lemberg <alex.lemberg@sandisk.com>
> ---
>  drivers/mmc/core/mmc.c  | 35 ++++++++++++++++++++++++++++-------
>  include/linux/mmc/mmc.h |  2 ++
>  2 files changed, 30 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
> index f70f6a1..21f5851 100644
> --- a/drivers/mmc/core/mmc.c
> +++ b/drivers/mmc/core/mmc.c
> @@ -1942,7 +1942,8 @@ static void mmc_detect(struct mmc_host *host)
>  	}
>  }
>
> -static int _mmc_suspend(struct mmc_host *host, bool is_suspend)
> +static int _mmc_suspend(struct mmc_host *host, bool is_suspend,
> +	bool is_runtime_pm)
>  {
>  	int err = 0;
>  	unsigned int notify_type = is_suspend ? EXT_CSD_POWER_OFF_SHORT :
> @@ -1953,10 +1954,30 @@ static int _mmc_suspend(struct mmc_host *host, bool is_suspend)
>  	if (mmc_card_suspended(host->card))
>  		goto out;
>
> -	if (mmc_card_doing_bkops(host->card)) {
> -		err = mmc_stop_bkops(host->card);
> -		if (err)
> +	if (mmc_card_doing_bkops(host->card) ||
> +		host->card->ext_csd.auto_bkops_en) {
> +		err = mmc_read_bkops_status(host->card);
> +		if (err) {
> +			pr_err("%s: error %d reading BKOPS Status\n",
> +				mmc_hostname(host), err);
>  			goto out;
> +		}
> +		if (is_runtime_pm && host->card->ext_csd.raw_bkops_status >=
> +				EXT_CSD_BKOPS_LEVEL_PM_SUSPEND) {
> +			/*
> +			 * We don’t allow Runtime Suspend while device still
> +			 * needs time to complete internal BKOPS, returning
> +			 * -EBUSY while BKOPS level is above
> +			 *  EXT_CSD_BKOPS_LEVEL_PM_SUSPEND
> +			 */
> +			err = -EBUSY;
> +			goto out;
> +		}
> +		if (mmc_card_doing_bkops(host->card)) {
> +			err = mmc_stop_bkops(host->card);
> +			if (err)
> +				goto out;
> +		}
>  	}
>
>  	err = mmc_flush_cache(host->card);
> @@ -1987,7 +2008,7 @@ static int mmc_suspend(struct mmc_host *host)
>  {
>  	int err;
>
> -	err = _mmc_suspend(host, true);
> +	err = _mmc_suspend(host, true, false);
>  	if (!err) {
>  		pm_runtime_disable(&host->card->dev);
>  		pm_runtime_set_suspended(&host->card->dev);
> @@ -2034,7 +2055,7 @@ static int mmc_shutdown(struct mmc_host *host)
>  		err = _mmc_resume(host);
>
>  	if (!err)
> -		err = _mmc_suspend(host, false);
> +		err = _mmc_suspend(host, false, false);
>
>  	return err;
>  }
> @@ -2058,7 +2079,7 @@ static int mmc_runtime_suspend(struct mmc_host *host)
>  	if (!(host->caps & MMC_CAP_AGGRESSIVE_PM))
>  		return 0;
>
> -	err = _mmc_suspend(host, true);
> +	err = _mmc_suspend(host, true, true);
>  	if (err)
>  		pr_err("%s: error %d doing aggressive suspend\n",
>  			mmc_hostname(host), err);
> diff --git a/include/linux/mmc/mmc.h b/include/linux/mmc/mmc.h
> index 126b8d5..2633274 100644
> --- a/include/linux/mmc/mmc.h
> +++ b/include/linux/mmc/mmc.h
> @@ -445,6 +445,8 @@ struct _mmc_csd {
>   */
>  #define EXT_CSD_BKOPS_LEVEL_2		0x2
>
> +#define EXT_CSD_BKOPS_LEVEL_PM_SUSPEND	EXT_CSD_BKOPS_LEVEL_2
> +
>  /*
>   * BKOPS modes
>   */
>


-- 
Best Regards
Shawn Lin