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In-Reply-To: <f178a0db-c978-42cf-1335-09b19d9574cc@intel.com>
From:   Ulf Hansson <ulf.hansson@linaro.org>
Date:   Thu, 2 Dec 2021 09:05:21 +0100
Message-ID: <CAPDyKFpihKExf2qiPuHtbJitP-q21rFCY-MNMdvAvbQd1C2_jA@mail.gmail.com>
Subject: Re: [PATCH V1] mmc: sdhci-msm: Add eMMC and SD card err_stat sysfs entry
To:     Adrian Hunter <adrian.hunter@intel.com>
Cc:     "Sajida Bhanu (Temp) (QUIC)" <quic_c_sbhanu@quicinc.com>,
        "riteshh@codeaurora.org" <riteshh@codeaurora.org>,
        "Asutosh Das (asd)" <asutoshd@quicinc.com>,
        "agross@kernel.org" <agross@kernel.org>,
        "bjorn.andersson@linaro.org" <bjorn.andersson@linaro.org>,
        "linux-mmc@vger.kernel.org" <linux-mmc@vger.kernel.org>,
        "linux-arm-msm@vger.kernel.org" <linux-arm-msm@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "stummala@codeaurora.org" <stummala@codeaurora.org>,
        "vbadigan@codeaurora.org" <vbadigan@codeaurora.org>,
        "Ram Prakash Gupta (QUIC)" <quic_rampraka@quicinc.com>,
        "Pradeep Pragallapati (QUIC)" <quic_pragalla@quicinc.com>,
        "sartgarg@codeaurora.org" <sartgarg@codeaurora.org>,
        "nitirawa@codeaurora.org" <nitirawa@codeaurora.org>,
        "sayalil@codeaurora.org" <sayalil@codeaurora.org>
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On Thu, 2 Dec 2021 at 08:28, Adrian Hunter <adrian.hunter@intel.com> wrote:
>
> On 02/12/2021 08:42, Sajida Bhanu (Temp) (QUIC) wrote:
> > Gentle Reminder.
> >
> > Thanks,
> > Sajida
> > -----Original Message-----
> > From: Sajida Bhanu (Temp) (QUIC) <quic_c_sbhanu@quicinc.com>
> > Sent: Friday, November 26, 2021 10:54 AM
> > To: Ulf Hansson <ulf.hansson@linaro.org>; Sajida Bhanu (Temp) (QUIC) <q=
uic_c_sbhanu@quicinc.com>
> > Cc: adrian.hunter@intel.com; riteshh@codeaurora.org; Asutosh Das (asd) =
<asutoshd@quicinc.com>; agross@kernel.org; bjorn.andersson@linaro.org; linu=
x-mmc@vger.kernel.org; linux-arm-msm@vger.kernel.org; linux-kernel@vger.ker=
nel.org; stummala@codeaurora.org; vbadigan@codeaurora.org; Ram Prakash Gupt=
a (QUIC) <quic_rampraka@quicinc.com>; Pradeep Pragallapati (QUIC) <quic_pra=
galla@quicinc.com>; sartgarg@codeaurora.org; nitirawa@codeaurora.org; sayal=
il@codeaurora.org
> > Subject: RE: [PATCH V1] mmc: sdhci-msm: Add eMMC and SD card err_stat s=
ysfs entry
> >
> >
> >
> > -----Original Message-----
> > From: Ulf Hansson <ulf.hansson@linaro.org>
> > Sent: Thursday, November 25, 2021 5:01 PM
> > To: Sajida Bhanu (Temp) (QUIC) <quic_c_sbhanu@quicinc.com>
> > Cc: adrian.hunter@intel.com; riteshh@codeaurora.org; Asutosh Das (asd) =
<asutoshd@quicinc.com>; agross@kernel.org; bjorn.andersson@linaro.org; linu=
x-mmc@vger.kernel.org; linux-arm-msm@vger.kernel.org; linux-kernel@vger.ker=
nel.org; stummala@codeaurora.org; vbadigan@codeaurora.org; Ram Prakash Gupt=
a (QUIC) <quic_rampraka@quicinc.com>; Pradeep Pragallapati (QUIC) <quic_pra=
galla@quicinc.com>; sartgarg@codeaurora.org; nitirawa@codeaurora.org; sayal=
il@codeaurora.org
> > Subject: Re: [PATCH V1] mmc: sdhci-msm: Add eMMC and SD card err_stat s=
ysfs entry
> >
> > On Wed, 17 Nov 2021 at 07:20, Shaik Sajida Bhanu <quic_c_sbhanu@quicinc=
.com> wrote:
> >>
> >> Add sysfs entry to query eMMC and SD card errors statistics.
> >> This feature is useful for debug and testing.
> >>
> >> Signed-off-by: Shaik Sajida Bhanu <quic_c_sbhanu@quicinc.com>
> >> ---
> >>  drivers/mmc/host/cqhci.h     |   1 +
> >>  drivers/mmc/host/sdhci-msm.c | 192 ++++++++++++++++++++++++++++++++++=
+++++++++
> >>  drivers/mmc/host/sdhci.c     |  17 ++++
> >>  drivers/mmc/host/sdhci.h     |   1 +
> >>  include/linux/mmc/host.h     |   1 +
> >>  5 files changed, 212 insertions(+)
> >
> > To allow an easier review, I strongly suggest splitting up the changes =
in smaller pieces. Maybe in three steps: add interfaces, implement them, ad=
d sysfs - or something along those lines.
> >
> > I am also trying to understand the benefit of having these stats availa=
ble. Can you perhaps share a little bit of background on how they are usabl=
e for you? Is it for debug purpose or does it have other purposes too?
> >
> > If it turns out that we agree on finding these stats valuable for us, t=
hen I am inclined to think that this should be integrated closer with the m=
mc core.
> >
> > The error codes that are propagated to the core from failed requests ar=
e common error codes, so we should be able to use that information from the=
 core itself, I think.
> >
> > Kind regards
> > Uffe
> >
> > Hi Ulf,
> >
> > Thanks for the review
> >
> > I am also trying to understand the benefit of having these stats availa=
ble. Can you perhaps share a little bit of background on how they are usabl=
e for you? Is it for debug purpose or does it have other purposes too?
> >
> >>>>>>>>>>>>> These changes for debug purpose only .. if any errors occur=
red while testing eMMC and SD card those will be captured in these sysfs en=
tries ,  we can directly go and check the sysfs entries and get to know wha=
t is the error occurred in driver level.
>
> I would suggest using debugfs and adding support in mmc host debugfs
> e.g.
>
> static inline void mmc_debugfs_err_stats_enable(struct mmc_host *mmc)
> {
>         mmc->err_stats_enabled =3D true;
> }
>
> enum mmc_err_stat {
>         MMC_ERR_CMD_TIMEOUT,
>         MMC_ERR_CMD_CRC,
>         MMC_ERR_DAT_TIMEOUT,
>         MMC_ERR_DAT_CRC,
>         MMC_ERR_AUTO_CMD,
>         MMC_ERR_ADMA,
>         MMC_ERR_TUNING,
>         MMC_ERR_CMDQ_RED,
>         MMC_ERR_CMDQ_GCE,
>         MMC_ERR_CMDQ_ICCE,
>         MMC_ERR_REQ_TIMEOUT,
>         MMC_ERR_CMDQ_REQ_TIMEOUT,
>         MMC_ERR_ICE_CFG,
>         MMC_ERR_MAX,
> };
>
> static inline void mmc_debugfs_err_stats_inc(struct mmc_host *mmc, enum m=
mc_err_stat stat)
> {
>         mmc->err_stats[stat] +=3D 1;
> }
>
> And amend mmc_add_host_debugfs() to create the err_stats file etc.
>
> sdhci.c could call mmc_debugfs_err_stats_enable() and mmc_debugfs_err_sta=
ts_inc() as needed.
> cqhci.c could call mmc_debugfs_err_stats_inc() as needed.
>
> Ulf, does that sound reasonable?

Yes, it does! Thanks for having a closer look!

[...]

Kind regards
Uffe