linux-kernel - Re: [PATCH V5 14/26] mmc: sdhci-uhs2: add set

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Date:   Tue, 13 Dec 2022 16:46:18 +0800
From:   Victor Shih <victorshihgli@...il.com>
To:     Adrian Hunter <adrian.hunter@...el.com>
Cc:     ulf.hansson@...aro.org, linux-mmc@...r.kernel.org,
        linux-kernel@...r.kernel.org, benchuanggli@...il.com,
        HL.Liu@...esyslogic.com.tw, Greg.tu@...esyslogic.com.tw,
        takahiro.akashi@...aro.org, dlunev@...omium.org,
        Victor Shih <victor.shih@...esyslogic.com.tw>,
        Ben Chuang <ben.chuang@...esyslogic.com.tw>
Subject: Re: [PATCH V5 14/26] mmc: sdhci-uhs2: add set_timeout()

Hi, Adrian

On Wed, Nov 2, 2022 at 1:14 AM Adrian Hunter <adrian.hunter@...el.com> wrote:
>
> On 19/10/22 14:06, Victor Shih wrote:
> > From: AKASHI Takahiro <takahiro.akashi@...aro.org>
> >
> > This is a UHS-II version of sdhci's set_timeout() operation.
> >
> > Signed-off-by: Ben Chuang <ben.chuang@...esyslogic.com.tw>
> > Signed-off-by: AKASHI Takahiro <takahiro.akashi@...aro.org>
> > ---
> >  drivers/mmc/host/sdhci-uhs2.c | 85 +++++++++++++++++++++++++++++++++++
> >  drivers/mmc/host/sdhci-uhs2.h |  1 +
> >  2 files changed, 86 insertions(+)
> >
> > diff --git a/drivers/mmc/host/sdhci-uhs2.c b/drivers/mmc/host/sdhci-uhs2.c
> > index 4dc3e904d7d2..2b90e5308764 100644
> > --- a/drivers/mmc/host/sdhci-uhs2.c
> > +++ b/drivers/mmc/host/sdhci-uhs2.c
> > @@ -196,6 +196,91 @@ void sdhci_uhs2_set_power(struct sdhci_host *host, unsigned char mode,
> >  }
> >  EXPORT_SYMBOL_GPL(sdhci_uhs2_set_power);
> >
> > +static u8 sdhci_calc_timeout_uhs2(struct sdhci_host *host, u8 *cmd_res,
> > +                               u8 *dead_lock)
> > +{
> > +     u8 count;
> > +     unsigned int cmd_res_timeout, dead_lock_timeout, current_timeout;
> > +
> > +     /*
> > +      * If the host controller provides us with an incorrect timeout
> > +      * value, just skip the check and use 0xE.  The hardware may take
> > +      * longer to time out, but that's much better than having a too-short
> > +      * timeout value.
> > +      */
> > +     if (host->quirks & SDHCI_QUIRK_BROKEN_TIMEOUT_VAL) {
> > +             *cmd_res = 0xE;
> > +             *dead_lock = 0xE;
> > +             return 0xE;
> > +     }
>
> Let's skip quirks you don't need for now.
>

I will update it in the patch#13 of the new [PATCH V6].

> > +
> > +     /* timeout in us */
> > +     cmd_res_timeout = 5 * 1000;
> > +     dead_lock_timeout = 1 * 1000 * 1000;
> > +
> > +     /*
> > +      * Figure out needed cycles.
> > +      * We do this in steps in order to fit inside a 32 bit int.
> > +      * The first step is the minimum timeout, which will have a
> > +      * minimum resolution of 6 bits:
> > +      * (1) 2^13*1000 > 2^22,
> > +      * (2) host->timeout_clk < 2^16
> > +      *     =>
> > +      *     (1) / (2) > 2^6
> > +      */
> > +     count = 0;
> > +     current_timeout = (1 << 13) * 1000 / host->timeout_clk;
> > +     while (current_timeout < cmd_res_timeout) {
> > +             count++;
> > +             current_timeout <<= 1;
> > +             if (count >= 0xF)
> > +                     break;
> > +     }
> > +
> > +     if (count >= 0xF) {
> > +             DBG("%s: Too large timeout 0x%x requested for CMD_RES!\n",
> > +                 mmc_hostname(host->mmc), count);
> > +             count = 0xE;
> > +     }
> > +     *cmd_res = count;
> > +
> > +     count = 0;
> > +     current_timeout = (1 << 13) * 1000 / host->timeout_clk;
> > +     while (current_timeout < dead_lock_timeout) {
> > +             count++;
> > +             current_timeout <<= 1;
> > +             if (count >= 0xF)
> > +                     break;
> > +     }
> > +
> > +     if (count >= 0xF) {
> > +             DBG("%s: Too large timeout 0x%x requested for DEADLOCK!\n",
> > +                 mmc_hostname(host->mmc), count);
> > +             count = 0xE;
> > +     }
> > +     *dead_lock = count;
> > +
> > +     return count;
> > +}
> > +
> > +static void __sdhci_uhs2_set_timeout(struct sdhci_host *host)
> > +{
> > +     u8 cmd_res, dead_lock;
> > +
> > +     sdhci_calc_timeout_uhs2(host, &cmd_res, &dead_lock);
> > +     cmd_res |= dead_lock << SDHCI_UHS2_TIMER_CTRL_DEADLOCK_SHIFT;
>
> GENMASK() and FIELD_PREP() please
>
> > +     sdhci_writeb(host, cmd_res, SDHCI_UHS2_TIMER_CTRL);
> > +}
> > +
> > +void sdhci_uhs2_set_timeout(struct sdhci_host *host, struct mmc_command *cmd)
> > +{
> > +     __sdhci_set_timeout(host, cmd);
> > +
> > +     if (host->mmc->flags & MMC_UHS2_SUPPORT)
>
>         if (sdhci_uhs2_mode(host))
>

I will update it in the patch#13 of the new [PATCH V6].

> > +             __sdhci_uhs2_set_timeout(host);
> > +}
> > +EXPORT_SYMBOL_GPL(sdhci_uhs2_set_timeout);
> > +
> >  /*****************************************************************************\
> >   *                                                                           *
> >   * MMC callbacks                                                             *
> > diff --git a/drivers/mmc/host/sdhci-uhs2.h b/drivers/mmc/host/sdhci-uhs2.h
> > index 3179915f7f79..5ea235b14108 100644
> > --- a/drivers/mmc/host/sdhci-uhs2.h
> > +++ b/drivers/mmc/host/sdhci-uhs2.h
> > @@ -215,5 +215,6 @@ bool sdhci_uhs2_mode(struct sdhci_host *host);
> >  void sdhci_uhs2_reset(struct sdhci_host *host, u16 mask);
> >  void sdhci_uhs2_set_power(struct sdhci_host *host, unsigned char mode,
> >                         unsigned short vdd);
> > +void sdhci_uhs2_set_timeout(struct sdhci_host *host, struct mmc_command *cmd);
> >
> >  #endif /* __SDHCI_UHS2_H */
>

Thanks, Victor Shih