linux-kernel - Re: LKFT: arm x15: mmc1: cache flush error -110

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Date:   Tue, 10 Mar 2020 17:22:00 -0700
From:   Sowjanya Komatineni <skomatineni@...dia.com>
To:     Ulf Hansson <ulf.hansson@...aro.org>
CC:     Jon Hunter <jonathanh@...dia.com>,
        Bitan Biswas <bbiswas@...dia.com>,
        Adrian Hunter <adrian.hunter@...el.com>,
        Naresh Kamboju <naresh.kamboju@...aro.org>,
        Jens Axboe <axboe@...nel.dk>,
        Alexei Starovoitov <ast@...nel.org>,
        linux-block <linux-block@...r.kernel.org>,
        <lkft-triage@...ts.linaro.org>,
        open list <linux-kernel@...r.kernel.org>,
        "linux-mmc@...r.kernel.org" <linux-mmc@...r.kernel.org>,
        Arnd Bergmann <arnd@...db.de>,
        John Stultz <john.stultz@...aro.org>,
        Faiz Abbas <faiz_abbas@...com>,
        Thierry Reding <treding@...dia.com>,
        Anders Roxell <anders.roxell@...aro.org>,
        Kishon <kishon@...com>
Subject: Re: LKFT: arm x15: mmc1: cache flush error -110


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
>>
>>
> Tested patches and they work good.
>
Sent sdhci-tegra v2 patches

- includes busy wait mode programming based on cmd busy_timeout

- enables MMC_CAP_WAIT_WHILE_BUSY

Thanks

Sowjanya