From: Jerome Brunet <jbrunet@baylibre.com> To: Martin Blumenstingl <martin.blumenstingl@googlemail.com> Cc: Ulf Hansson <ulf.hansson@linaro.org>, Kevin Hilman <khilman@baylibre.com>, linux-amlogic@lists.infradead.org, linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 5/7] mmc: meson-gx: avoid clock glitch when switching to DDR modes Date: Thu, 18 Apr 2019 22:46:05 +0200 [thread overview] Message-ID: <8316d7875bf0479e91cc11ce5fbf3b2e21f92a2c.camel@baylibre.com> (raw) In-Reply-To: <CAFBinCCAbMpWYY6-W+909Q=jLpweC2F6ED6CVf6zVGrRiA1hxg@mail.gmail.com> On Thu, 2019-04-18 at 22:16 +0200, Martin Blumenstingl wrote: > Hi Jerome, > > On Wed, Apr 17, 2019 at 10:44 PM Jerome Brunet <jbrunet@baylibre.com> wrote: > > Activating DDR in the Amlogic mmc controller, among other things, will > > divide the output clock by 2. So by activating it with clock on, we are > > creating a glitch on the output. > > > > Instead, let's deal with DDR when the clock output is off, when setting > > the clock. > > > > Signed-off-by: Jerome Brunet <jbrunet@baylibre.com> > it seems that this patch breaks SD card on my Khadas VIM and Khadas VIM2. The error I see in your logs is with eMMC and hs200, not SD card. Either way, There is something I don't really get. eMMC should not go through any DDR mode to reach HS200 (which is an SDR mode), neither should SD to reach HS. All this does is flipping the DDR bit (when necessary) when clock if off for the mmc device, avoiding a glitch on clk line. This patch should not make any difference for SDR only setup, Maybe I missed something, but I don't see how it could make anything different for SDR only. I (repeatedly) tested both vim1 and vim2, without seeing this issue, so I can't debug this. I'll need more detail to progress, something does not make sense here. > I used git bisect within this series to find that issue. > applying your .dts patches on top doesn't fix it > > two boot logs attached: > * kvim-broken.txt has patches 1-5 (= including this patch) applied > * kvim-working.txt has only patches 1-4 (= excluding this patch) applied > > > Regards > Martin
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From: Jerome Brunet <jbrunet@baylibre.com> To: Martin Blumenstingl <martin.blumenstingl@googlemail.com> Cc: Kevin Hilman <khilman@baylibre.com>, Ulf Hansson <ulf.hansson@linaro.org>, linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-amlogic@lists.infradead.org Subject: Re: [PATCH 5/7] mmc: meson-gx: avoid clock glitch when switching to DDR modes Date: Thu, 18 Apr 2019 22:46:05 +0200 [thread overview] Message-ID: <8316d7875bf0479e91cc11ce5fbf3b2e21f92a2c.camel@baylibre.com> (raw) In-Reply-To: <CAFBinCCAbMpWYY6-W+909Q=jLpweC2F6ED6CVf6zVGrRiA1hxg@mail.gmail.com> On Thu, 2019-04-18 at 22:16 +0200, Martin Blumenstingl wrote: > Hi Jerome, > > On Wed, Apr 17, 2019 at 10:44 PM Jerome Brunet <jbrunet@baylibre.com> wrote: > > Activating DDR in the Amlogic mmc controller, among other things, will > > divide the output clock by 2. So by activating it with clock on, we are > > creating a glitch on the output. > > > > Instead, let's deal with DDR when the clock output is off, when setting > > the clock. > > > > Signed-off-by: Jerome Brunet <jbrunet@baylibre.com> > it seems that this patch breaks SD card on my Khadas VIM and Khadas VIM2. The error I see in your logs is with eMMC and hs200, not SD card. Either way, There is something I don't really get. eMMC should not go through any DDR mode to reach HS200 (which is an SDR mode), neither should SD to reach HS. All this does is flipping the DDR bit (when necessary) when clock if off for the mmc device, avoiding a glitch on clk line. This patch should not make any difference for SDR only setup, Maybe I missed something, but I don't see how it could make anything different for SDR only. I (repeatedly) tested both vim1 and vim2, without seeing this issue, so I can't debug this. I'll need more detail to progress, something does not make sense here. > I used git bisect within this series to find that issue. > applying your .dts patches on top doesn't fix it > > two boot logs attached: > * kvim-broken.txt has patches 1-5 (= including this patch) applied > * kvim-working.txt has only patches 1-4 (= excluding this patch) applied > > > Regards > Martin _______________________________________________ linux-amlogic mailing list linux-amlogic@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-amlogic
next prev parent reply other threads:[~2019-04-18 20:46 UTC|newest] Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-04-17 20:43 [PATCH 0/7] mmc: meson-gx: clean up and tuning update Jerome Brunet 2019-04-17 20:43 ` Jerome Brunet 2019-04-17 20:43 ` [PATCH 1/7] mmc: meson-gx: remove open coded read with timeout Jerome Brunet 2019-04-17 20:43 ` Jerome Brunet 2019-04-18 20:18 ` Martin Blumenstingl 2019-04-18 20:18 ` Martin Blumenstingl 2019-04-17 20:43 ` [PATCH 2/7] mmc: meson-gx: ack only raised irq Jerome Brunet 2019-04-17 20:43 ` Jerome Brunet 2019-04-17 20:43 ` [PATCH 3/7] mmc: meson-gx: irq is not shared Jerome Brunet 2019-04-17 20:43 ` Jerome Brunet 2019-04-18 19:52 ` Martin Blumenstingl 2019-04-18 19:52 ` Martin Blumenstingl 2019-04-17 20:43 ` [PATCH 4/7] mmc: meson-gx: disable HS400 Jerome Brunet 2019-04-17 20:43 ` Jerome Brunet 2019-04-17 20:43 ` [PATCH 5/7] mmc: meson-gx: avoid clock glitch when switching to DDR modes Jerome Brunet 2019-04-17 20:43 ` Jerome Brunet 2019-04-18 20:16 ` Martin Blumenstingl 2019-04-18 20:16 ` Martin Blumenstingl 2019-04-18 20:46 ` Jerome Brunet [this message] 2019-04-18 20:46 ` Jerome Brunet 2019-04-18 20:53 ` Martin Blumenstingl 2019-04-18 20:53 ` Martin Blumenstingl 2019-04-18 21:15 ` Jerome Brunet 2019-04-18 21:15 ` Jerome Brunet 2019-04-19 8:53 ` Jerome Brunet 2019-04-19 8:53 ` Jerome Brunet 2019-04-20 9:23 ` Martin Blumenstingl 2019-04-20 9:23 ` Martin Blumenstingl 2019-04-17 20:43 ` [PATCH 6/7] mmc: meson-gx: remove Rx phase tuning Jerome Brunet 2019-04-17 20:43 ` Jerome Brunet 2019-04-17 20:43 ` [PATCH 7/7] mmc: meson-gx: add signal resampling tuning Jerome Brunet 2019-04-17 20:43 ` Jerome Brunet
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