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From:   Ulf Hansson <ulf.hansson@linaro.org>
Date:   Wed, 11 Mar 2020 09:34:22 +0100
Message-ID: <CAPDyKFqWRGK6LCevwXQoZnRqfMkUDWNUMqbGqnqv+OopmhvBeg@mail.gmail.com>
Subject: Re: LKFT: arm x15: mmc1: cache flush error -110
To:     Sowjanya Komatineni <skomatineni@nvidia.com>
Cc:     Jon Hunter <jonathanh@nvidia.com>,
        Bitan Biswas <bbiswas@nvidia.com>,
        Adrian Hunter <adrian.hunter@intel.com>,
        Naresh Kamboju <naresh.kamboju@linaro.org>,
        Jens Axboe <axboe@kernel.dk>,
        Alexei Starovoitov <ast@kernel.org>,
        linux-block <linux-block@vger.kernel.org>,
        lkft-triage@lists.linaro.org,
        open list <linux-kernel@vger.kernel.org>,
        "linux-mmc@vger.kernel.org" <linux-mmc@vger.kernel.org>,
        Arnd Bergmann <arnd@arndb.de>,
        John Stultz <john.stultz@linaro.org>,
        Faiz Abbas <faiz_abbas@ti.com>,
        Thierry Reding <treding@nvidia.com>,
        Anders Roxell <anders.roxell@linaro.org>,
        Kishon <kishon@ti.com>
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On Wed, 11 Mar 2020 at 01:19, Sowjanya Komatineni
<skomatineni@nvidia.com> wrote:
>
>
> On 3/10/20 4:10 PM, Sowjanya Komatineni wrote:
> >
> > On 3/10/20 2:59 PM, Sowjanya Komatineni wrote:
> >>
> >> On 3/10/20 10:27 AM, Sowjanya Komatineni wrote:
> >>>
> >>> On 3/10/20 10:09 AM, Ulf Hansson wrote:
> >>>> External email: Use caution opening links or attachments
> >>>>
> >>>>
> >>>> [...]
> >>>>
> >>>>>>>> I would like to get the regression fixed asap, but I also would
> >>>>>>>> like
> >>>>>>>> to avoid reverting patches, unless really necessary. May I
> >>>>>>>> propose the
> >>>>>>>> following two options.
> >>>>>>>>
> >>>>>>>> 1. Find out why polling with ->card_busy() or CMD13, for a CMD6
> >>>>>>>> with
> >>>>>>>> an R1 response doesn't work - and then fix that behaviour.
> >>>>>>>>
> >>>>>>>> 2. Set the mmc->max_busy_timeout to zero for sdhci-tegra, which
> >>>>>>>> makes
> >>>>>>>> the core to always use R1B for CMD6 (and erase). This also
> >>>>>>>> means that
> >>>>>>>> when the cmd->busy_timeout becomes longer than 11s, sdhci-tegra
> >>>>>>>> must
> >>>>>>>> disable the HW busy timeout and just wait "forever".
> >>>>>>>>
> >>>>>>>> If you decide for 2, you can add the software timeout support
> >>>>>>>> on top,
> >>>>>>>> but make that can be considered as a next step of an improvement,
> >>>>>>>> rather than needed as fix. Note that, I believe there are some
> >>>>>>>> support
> >>>>>>>> for software timeout already in the sdhci core, maybe you need to
> >>>>>>>> tweak it a bit for your case, I don't know.
> >>>>>>>>
> >>>>>>>> Kind regards
> >>>>>>>> Uffe
> >>>>>>> Hi Uffe
> >>>>>>>
> >>>>>>> Will go with 2nd option and will send patches out when ready.
> >>>>>> Okay, good.
> >>>>>>
> >>>>>>> BTW, Tegra host also supports
> >>>>>>> SDHCI_QUIRK_DATA_TIMEOUT_USES_SDCLK for
> >>>>>>> data timeout based on host clock when using finite mode (HW busy
> >>>>>>> detection based on DATA TIMEOUT count value when cmd operation
> >>>>>>> timeout
> >>>>>>> is < 11s for tegra host).
> >>>>>>>
> >>>>>>> So, looks like we cant set host max_busy_timeout to 0 for Tegra
> >>>>>>> host to
> >>>>>>> force R1B during SWITCH and SLEEP_AWAKE.
> >>>>>>>
> >>>>>>> So, was thinking to introduce host capability
> >>>>>>> MMC_CAP2_LONG_WAIT_HW_BUSY
> >>>>>>> which can be used for hosts supporting long or infinite HW busy
> >>>>>>> wait
> >>>>>>> detection and will update mmc and mmc_ops drivers to not allow
> >>>>>>> convert
> >>>>>>> R1B to R1B for hosts with this capability during SLEEP_AWAKE and
> >>>>>>> SWITCH.
> >>>>>> That seems reasonable, it becomes probably both easier and
> >>>>>> clearer by
> >>>>>> adding a new host cap.
> >>>>>>
> >>>>>> In any case, let me help out and cook a patch for this for the core
> >>>>>> part (I leave the sdhci change to you). It may be a bit tricky,
> >>>>>> especially since I have currently queued a bunch of new changes for
> >>>>>> v5.7, that enables more users of mmc_poll_for_busy() in the core.
> >>>>>> Maybe I need to temporarily drop them, so we can fix these problems
> >>>>>> first. I will check.
> >>>>>>
> >>>>>> Probably, I would also name the cap MMC_CAP_HW_NEED_RSP_BUSY, as
> >>>>>> that
> >>>>>> seems to be describing the common problem we have for sdhci
> >>>>>> omap/tegra.
> >>>>>>
> >>>>>> Finally, it seems like MMC_CAP_WAIT_WHILE_BUSY should be set for
> >>>>>> sdhci- tegra, so while at it, perhaps you can cook a patch for
> >>>>>> that as
> >>>>>> well.
> >>>>>>
> >>>>>> Kind regards
> >>>>>> Uffe
> >>>>> OK, I sent v1 yesterday. Please ignore them then.
> >>>> Oh, I haven't seen them. In any case, I am ignoring them.
> >>>>
> >>>>> Will send out patches only for HW busy wait modes program based on
> >>>>> cmd
> >>>>> timeout and WAIT_WHILE_BUSY enabled.
> >>>> Great, thanks!
> >>>>
> >>>> Please help test the series I just posted as well, if you have the
> >>>> time ofcourse.
> >>>>
> >>>> Kind regards
> >>>> Uffe
> >>>
> >>> Sure,
> >>>
> >>> Thanks
> >>>
> >>> Sowjanya
> >>
> >>
> >> mmc_sleep() also needs update to force R1B when host sets capability
> >> MMC_CAP_NEED_RSP_BUSY

Yes, I am on it! Thanks!

> >>
> >>
> > Tested patches and they work good.

Great, I am adding your tested-by tag then.

> >
> Sent sdhci-tegra v2 patches
>
> - includes busy wait mode programming based on cmd busy_timeout
>
> - enables MMC_CAP_WAIT_WHILE_BUSY

Sounds great, but I don't see the patches on the mailing list, nor did
they reach the mmc patchtracker.

Seems like you probably need to check your email settings when sending patches.

Kind regards
Uffe