linux-kernel - Re: [PATCH v2] mmc: sdhci-acpi: Fix HS400 tuning for AMDI0040

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Date:   Fri, 21 Aug 2020 23:56:54 +0200
From:   Ulf Hansson <ulf.hansson@...aro.org>
To:     Raul Rangel <rrangel@...omium.org>
Cc:     Nicolas Boichat <drinkcat@...omium.org>,
        Adrian Hunter <adrian.hunter@...el.com>,
        Akshu Agrawal <Akshu.Agrawal@....com>,
        "Wang, Chris" <chris.wang@....com>,
        "Shah, Nehal-bakulchandra" <Nehal-bakulchandra.Shah@....com>,
        lkml <linux-kernel@...r.kernel.org>,
        "linux-mmc@...r.kernel.org" <linux-mmc@...r.kernel.org>,
        Steven Rostedt <rostedt@...dmis.org>
Subject: Re: [PATCH v2] mmc: sdhci-acpi: Fix HS400 tuning for AMDI0040

On Fri, 21 Aug 2020 at 16:31, Raul Rangel <rrangel@...omium.org> wrote:
>
> Oops, what was embarrassing! Thanks Ulf for removing it. Thanks Nick for caching that.

No worries, we all make mistakes. The important thing is that we take
good care of fixing them as soon as possible.

Kind regards
Uffe

>
> On Fri, Aug 21, 2020 at 3:04 AM Ulf Hansson <ulf.hansson@...aro.org> wrote:
>>
>> On Fri, 21 Aug 2020 at 02:24, Nicolas Boichat <drinkcat@...omium.org> wrote:
>> >
>> > On Thu, Aug 20, 2020 at 3:00 AM Raul E Rangel <rrangel@...omium.org> wrote:
>> > >
>> > > The AMD eMMC Controller can only use the tuned clock while in HS200 and
>> > > HS400 mode. If we switch to a different mode, we need to disable the
>> > > tuned clock. If we have previously performed tuning and switch back to
>> > > HS200 or HS400, we can re-enable the tuned clock.
>> > >
>> > > Previously the tuned clock was not getting disabled when switching to
>> > > DDR52 which is part of the HS400 tuning sequence.
>> > >
>> > > Fixes: 34597a3f60b1 ("mmc: sdhci-acpi: Add support for ACPI HID of AMD Controller with HS400")
>> > > Signed-off-by: Raul E Rangel <rrangel@...omium.org>
>> > > Acked-by: Adrian Hunter <adrian.hunter@...el.com>
>>
>> Applied for fixes, by dropping the trace_printk below, thanks!
>>
>> Kind regards
>> Uffe
>>
>>
>> > > ---
>> > >
>> > > Changes in v2:
>> > > - Added static to amd_sdhci_execute_tuning
>> > >
>> > >  drivers/mmc/host/sdhci-acpi.c | 68 +++++++++++++++++++++++++++++------
>> > >  1 file changed, 58 insertions(+), 10 deletions(-)
>> > [snip]
>> > > +               /* DLL is only required for HS400 */
>> > > +               if (host->timing == MMC_TIMING_MMC_HS400 &&
>> > > +                   !amd_host->dll_enabled) {
>> > > +                       trace_printk("%s: Enabling DLL\n", __func__);
>> >
>> > Please do not use trace_printk in production code [1,2], it is only
>> > meant for debug use. Consider using dev_dbg.
>> >
>> > [1] https://elixir.bootlin.com/linux/v5.8/source/kernel/trace/trace.c#L3158
>> > [2] https://elixir.bootlin.com/linux/v5.8/source/include/linux/kernel.h#L766
>> >
>> > > +                       sdhci_acpi_amd_hs400_dll(host);
>> > > +                       amd_host->dll_enabled = true;
>> > > +               }
>> > >         }