Re: [PATCH 06/10] mmc: core: Respect host's max_busy_timeout when sending sleep cmd

[Adrian Hunter <adrian.hunter@intel.com>]

On 22/01/14 17:00, Ulf Hansson wrote:
> When sending the sleep command for host drivers supporting
> MMC_CAP_WAIT_WHILE_BUSY, we need to confirm that max_busy_timeout is
> big enough comparing to the sleep timeout specified from card's
> EXT_CSD. If this isn't case, we use a R1 response instead of R1B and
> fallback to use a delay instead.
> 
> Do note that a max_busy_timeout set to zero by the host, is interpreted
> as it can cope with whatever timeout the mmc core provides it with.
> 
> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
> ---
>  drivers/mmc/core/mmc.c |   19 ++++++++++++++++---
>  1 file changed, 16 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
> index 897fdd1..32e1546 100644
> --- a/drivers/mmc/core/mmc.c
> +++ b/drivers/mmc/core/mmc.c
> @@ -1359,6 +1359,8 @@ static int mmc_sleep(struct mmc_host *host)
>  {
>  	struct mmc_command cmd = {0};
>  	struct mmc_card *card = host->card;
> +	unsigned int timeout_ms = DIV_ROUND_UP(card->ext_csd.sa_timeout, 10000);
> +	unsigned int max_busy_timeout;
>  	int err;
>  
>  	if (host->caps2 & MMC_CAP2_NO_SLEEP_CMD)
> @@ -1372,7 +1374,18 @@ static int mmc_sleep(struct mmc_host *host)
>  	cmd.arg = card->rca << 16;
>  	cmd.arg |= 1 << 15;
>  
> -	cmd.flags = MMC_RSP_R1B | MMC_CMD_AC;
> +	/* We interpret unspecified timeouts as the host can cope with all. */
> +	max_busy_timeout = host->max_busy_timeout ?
> +			host->max_busy_timeout : timeout_ms;
> +
> +	if ((host->caps & MMC_CAP_WAIT_WHILE_BUSY) &&
> +		(timeout_ms <= max_busy_timeout)) {
> +		cmd.flags = MMC_RSP_R1B | MMC_CMD_AC;
> +		cmd.busy_timeout = timeout_ms;
> +	} else {
> +		cmd.flags = MMC_RSP_R1 | MMC_CMD_AC;
> +	}

I do not see why this is related to MMC_CAP_WAIT_WHILE_BUSY.
Why not just:

	if (host->max_busy_timeout && timeout_ms > host->max_busy_timeout) {
		cmd.flags = MMC_RSP_R1 | MMC_CMD_AC;
	} else {
		cmd.flags = MMC_RSP_R1B | MMC_CMD_AC;
		cmd.busy_timeout = timeout_ms;
	}

> +
>  	err = mmc_wait_for_cmd(host, &cmd, 0);
>  	if (err)
>  		return err;
> @@ -1383,8 +1396,8 @@ static int mmc_sleep(struct mmc_host *host)
>  	 * SEND_STATUS command to poll the status because that command (and most
>  	 * others) is invalid while the card sleeps.
>  	 */
> -	if (!(host->caps & MMC_CAP_WAIT_WHILE_BUSY))
> -		mmc_delay(DIV_ROUND_UP(card->ext_csd.sa_timeout, 10000));
> +	if (!cmd.busy_timeout)
> +		mmc_delay(timeout_ms);

And this becomes:

	if (!cmd.busy_timeout || !(host->caps & MMC_CAP_WAIT_WHILE_BUSY))
		mmc_delay(timeout_ms);

>  
>  	return err;
>  }
>