Re: [PATCH v2] mmc: core: Do not poll for busy with status cmd for all switch cmds

[Jaehoon Chung <jh80.chung@samsung.com>]

It looks good to me.

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

On 10/22/2013 06:24 PM, Ulf Hansson wrote:
> Some switch operations like poweroff notify, shall according to the
> spec not be followed by any other new commands. For these cases and
> when the host does'nt support MMC_CAP_WAIT_WHILE_BUSY, we must not
> send status commands to poll for busy detection. Instead wait for
> the stated timeout from the EXT_CSD before completing the request.
> 
> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
> Cc: Jaehoon Chung <jh80.chung@samsung.com>
> ---
> 
> Changes in v2:
> 	Rebase towards latest mmc-next.
> 
> ---
>  drivers/mmc/core/core.c    |    2 +-
>  drivers/mmc/core/mmc.c     |    6 +++---
>  drivers/mmc/core/mmc_ops.c |   23 ++++++++++++++++++-----
>  include/linux/mmc/core.h   |    3 ++-
>  4 files changed, 24 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
> index 006ead2..0292ad4 100644
> --- a/drivers/mmc/core/core.c
> +++ b/drivers/mmc/core/core.c
> @@ -301,7 +301,7 @@ void mmc_start_bkops(struct mmc_card *card, bool from_exception)
>  	}
>  
>  	err = __mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
> -			EXT_CSD_BKOPS_START, 1, timeout, use_busy_signal);
> +			EXT_CSD_BKOPS_START, 1, timeout, use_busy_signal, true);
>  	if (err) {
>  		pr_warn("%s: Error %d starting bkops\n",
>  			mmc_hostname(card->host), err);
> diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
> index 6d02012..8f0c516 100644
> --- a/drivers/mmc/core/mmc.c
> +++ b/drivers/mmc/core/mmc.c
> @@ -1404,9 +1404,9 @@ static int mmc_poweroff_notify(struct mmc_card *card, unsigned int notify_type)
>  	if (notify_type == EXT_CSD_POWER_OFF_LONG)
>  		timeout = card->ext_csd.power_off_longtime;
>  
> -	err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
> -			 EXT_CSD_POWER_OFF_NOTIFICATION,
> -			 notify_type, timeout);
> +	err = __mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
> +			EXT_CSD_POWER_OFF_NOTIFICATION,
> +			notify_type, timeout, true, false);
>  	if (err)
>  		pr_err("%s: Power Off Notification timed out, %u\n",
>  		       mmc_hostname(card->host), timeout);
> diff --git a/drivers/mmc/core/mmc_ops.c b/drivers/mmc/core/mmc_ops.c
> index 37f7d70..aae8d8b 100644
> --- a/drivers/mmc/core/mmc_ops.c
> +++ b/drivers/mmc/core/mmc_ops.c
> @@ -404,11 +404,12 @@ int mmc_spi_set_crc(struct mmc_host *host, int use_crc)
>   *	@timeout_ms: timeout (ms) for operation performed by register write,
>   *                   timeout of zero implies maximum possible timeout
>   *	@use_busy_signal: use the busy signal as response type
> + *	@send_status: send status cmd to poll for busy
>   *
>   *	Modifies the EXT_CSD register for selected card.
>   */
>  int __mmc_switch(struct mmc_card *card, u8 set, u8 index, u8 value,
> -	       unsigned int timeout_ms, bool use_busy_signal)
> +		unsigned int timeout_ms, bool use_busy_signal, bool send_status)
>  {
>  	int err;
>  	struct mmc_command cmd = {0};
> @@ -454,14 +455,26 @@ int __mmc_switch(struct mmc_card *card, u8 set, u8 index, u8 value,
>  
>  	timeout = jiffies + msecs_to_jiffies(MMC_OPS_TIMEOUT_MS);
>  	do {
> -		err = __mmc_send_status(card, &status, ignore_crc);
> -		if (err)
> -			return err;
> +		if (send_status) {
> +			err = __mmc_send_status(card, &status, ignore_crc);
> +			if (err)
> +				return err;
> +		}
>  		if (card->host->caps & MMC_CAP_WAIT_WHILE_BUSY)
>  			break;
>  		if (mmc_host_is_spi(card->host))
>  			break;
>  
> +		/*
> +		 * We are not allowed to issue a status command and the host
> +		 * does'nt support MMC_CAP_WAIT_WHILE_BUSY, then we can only
> +		 * rely on waiting for the stated timeout to be sufficient.
> +		 */
> +		if (!send_status) {
> +			mmc_delay(timeout_ms);
> +			return 0;
> +		}
> +
>  		/* Timeout if the device never leaves the program state. */
>  		if (time_after(jiffies, timeout)) {
>  			pr_err("%s: Card stuck in programming state! %s\n",
> @@ -488,7 +501,7 @@ EXPORT_SYMBOL_GPL(__mmc_switch);
>  int mmc_switch(struct mmc_card *card, u8 set, u8 index, u8 value,
>  		unsigned int timeout_ms)
>  {
> -	return __mmc_switch(card, set, index, value, timeout_ms, true);
> +	return __mmc_switch(card, set, index, value, timeout_ms, true, true);
>  }
>  EXPORT_SYMBOL_GPL(mmc_switch);
>  
> diff --git a/include/linux/mmc/core.h b/include/linux/mmc/core.h
> index a00fc49..87079fc 100644
> --- a/include/linux/mmc/core.h
> +++ b/include/linux/mmc/core.h
> @@ -151,7 +151,8 @@ extern int mmc_app_cmd(struct mmc_host *, struct mmc_card *);
>  extern int mmc_wait_for_app_cmd(struct mmc_host *, struct mmc_card *,
>  	struct mmc_command *, int);
>  extern void mmc_start_bkops(struct mmc_card *card, bool from_exception);
> -extern int __mmc_switch(struct mmc_card *, u8, u8, u8, unsigned int, bool);
> +extern int __mmc_switch(struct mmc_card *, u8, u8, u8, unsigned int, bool,
> +			bool);
>  extern int mmc_switch(struct mmc_card *, u8, u8, u8, unsigned int);
>  extern int mmc_send_ext_csd(struct mmc_card *card, u8 *ext_csd);
>  
>