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

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Date:   Wed, 15 Sep 2021 14:48:51 +0200
From:   Ulf Hansson <ulf.hansson@...aro.org>
To:     Bean Huo <huobean@...il.com>
Cc:     Adrian Hunter <adrian.hunter@...el.com>,
        Wolfram Sang <wsa+renesas@...g-engineering.com>,
        Linus Walleij <linus.walleij@...aro.org>,
        Avri Altman <avri.altman@....com>,
        linux-mmc <linux-mmc@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        "Bean Huo (beanhuo)" <beanhuo@...ron.com>
Subject: Re: [PATCH v1 2/2] mmc: core: No need to calculate the timeout value
 for CQE data transmission

On Wed, 15 Sept 2021 at 11:54, Bean Huo <huobean@...il.com> wrote:
>
> On Tue, 2021-09-14 at 10:13 +0200, Ulf Hansson wrote:
> > >          }
> > > +       /*
> > > +        * 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.
>
> Uffe,
>
> My apologies for this, I forgot to check hsq, hsq will call
> sdhci_send_command() as well.
>
>
> How about changing it to this?
>
>
> diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
> index 240c5af793dc..7235e398ef93 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;
>         }
>
> +       /*
> +        * For the CQE use case, the data transfer timeout will be set
> a maximum
> +        * timeout value in HW timer in function sdhci_cqe_enable(),
> so, no need
> +        * to go through the below algorithm.
> +        */
> +       if (host->cqe_enabled && !host->hsq_enabled)
> +               return;

Are you really sure the timeout isn't used (or could make sense to be
used for new cases)?

For example, we also have mtk-sd, which doesn't make use of sdhci_cqe_enable().

>         /*
>          * SD cards use a 100 multiplier rather than 10
>          */
>
> I have another timeout change associated with data transfer as well, if
> this change is acceptible, I will submit it with that together.
>
> Kind regards,
> Bean
>

Kind regards
Uffe