Re: [PATCH v1 2/2] mmc: core: No need to calculate the timeout value for CQE data transmission

From: Ulf Hansson <ulf.hansson@linaro.org>
To: Bean Huo <huobean@gmail.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>,
	Wolfram Sang <wsa+renesas@sang-engineering.com>,
	Linus Walleij <linus.walleij@linaro.org>,
	Avri Altman <avri.altman@wdc.com>,
	linux-mmc <linux-mmc@vger.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	"Bean Huo (beanhuo)" <beanhuo@micron.com>
Subject: Re: [PATCH v1 2/2] mmc: core: No need to calculate the timeout value for CQE data transmission
Date: Tue, 14 Sep 2021 10:13:48 +0200	[thread overview]
Message-ID: <CAPDyKFpC6iei96n-UcRTNrxTaHeejzfQX+rka7GSwSZjXN7-4g@mail.gmail.com> (raw)
In-Reply-To: <20210907151204.118861-3-huobean@gmail.com>

On Tue, 7 Sept 2021 at 17:12, Bean Huo <huobean@gmail.com> wrote:
>
> From: Bean Huo <beanhuo@micron.com>
>
> In case CQE is enabled, the timeout value of data transmission is always
> set to be maximum in sdhci_cqe_enable(), so, calculating its timeout value
> is obviously superfluous. Change to return directly, which can save some CPU
> cycle time.
>
> Signed-off-by: Bean Huo <beanhuo@micron.com>
> ---
>  drivers/mmc/core/core.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
>
> diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
> index 240c5af793dc..0b571a3bc988 100644
> --- a/drivers/mmc/core/core.c
> +++ b/drivers/mmc/core/core.c
> @@ -649,6 +649,7 @@ EXPORT_SYMBOL(mmc_wait_for_cmd);
>  void mmc_set_data_timeout(struct mmc_data *data, const struct mmc_card *card)
>  {
>         unsigned int mult;
> +       struct mmc_host *host = card->host;
>
>         /*
>          * SDIO cards only define an upper 1 s limit on access.
> @@ -659,6 +660,13 @@ void mmc_set_data_timeout(struct mmc_data *data, const struct mmc_card *card)
>                 return;
>         }
>
> +       /*
> +        * In case CQE is enabled, the timeout will be set a maximum timeout in
> +        * sdhci_cqe_enable(), so, no need to go through the below algorithm.
> +        */
> +       if (host->cqe_enabled)

 I don't think this is a good idea. For example, host->cqe_enabled is
set for the hsq case well.

> +               return;
> +
>         /*
>          * SD cards use a 100 multiplier rather than 10
>          */

Kind regards
Uffe