linux-kernel - Re: [PATCH V7 13/23] mmc: sdhci-uhs2: add set

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Message-ID: <CAK00qKB-xp1pJQevUH4FFYC8JGORXGqAtwaKB9Um9P=jdm5ZPA@mail.gmail.com>
Date:   Wed, 21 Jun 2023 18:29:03 +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 V7 13/23] mmc: sdhci-uhs2: add set_timeout()

Hi, Adrian

On Wed, Apr 12, 2023 at 9:10 PM Adrian Hunter <adrian.hunter@...el.com> wrote:
>
> On 31/03/23 13:55, Victor Shih wrote:
> > 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>
> > Signed-off-by: Victor Shih <victor.shih@...esyslogic.com.tw>
> > ---
> >  drivers/mmc/host/sdhci-uhs2.c | 72 +++++++++++++++++++++++++++++++++++
> >  drivers/mmc/host/sdhci-uhs2.h |  1 +
> >  2 files changed, 73 insertions(+)
> >
> > diff --git a/drivers/mmc/host/sdhci-uhs2.c b/drivers/mmc/host/sdhci-uhs2.c
> > index 388d87537847..e2e9ce51b768 100644
> > --- a/drivers/mmc/host/sdhci-uhs2.c
> > +++ b/drivers/mmc/host/sdhci-uhs2.c
> > @@ -13,6 +13,7 @@
> >  #include <linux/delay.h>
> >  #include <linux/module.h>
> >  #include <linux/iopoll.h>
> > +#include <linux/bitfield.h>
> >
> >  #include "sdhci.h"
> >  #include "sdhci-uhs2.h"
> > @@ -144,6 +145,77 @@ static void sdhci_uhs2_set_power(struct sdhci_host *host, unsigned char mode,
> >       }
> >  }
> >
> > +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;
> > +     /* timeout in us */
> > +     cmd_res_timeout = 5 * 1000;
> > +     dead_lock_timeout = 1 * 1000 * 1000;
>
> Initialization should be combined with declaration,
> and by descending line length looks neater i.e.
>
>         unsigned int dead_lock_timeout = 1 * 1000 * 1000;
>         unsigned int cmd_res_timeout = 5 * 1000;
>         unsigned int current_timeout;
>         u8 count;
>

I will update it to the V8 version.

> > +
> > +     /*
> > +      * 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 |= FIELD_PREP(SDHCI_UHS2_TIMER_CTRL_DEADLOCK_MASK, dead_lock);
> > +     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 (sdhci_uhs2_mode(host))
> > +             __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 6834893eee85..fc03a178b676 100644
> > --- a/drivers/mmc/host/sdhci-uhs2.h
> > +++ b/drivers/mmc/host/sdhci-uhs2.h
> > @@ -180,5 +180,6 @@ struct sdhci_host;
> >  void sdhci_uhs2_dump_regs(struct sdhci_host *host);
> >  bool sdhci_uhs2_mode(struct sdhci_host *host);
> >  void sdhci_uhs2_reset(struct sdhci_host *host, u16 mask);
> > +void sdhci_uhs2_set_timeout(struct sdhci_host *host, struct mmc_command *cmd);
>
> Really should forward declare 'struct mmc_command' as was done
> for 'struct sdhci_host'
>

I will update it to the V8 version.

> >
> >  #endif /* __SDHCI_UHS2_H */
>

Thanks, Victor Shih