From: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
To: Stefan Wahren <stefan.wahren@i2se.com>,
Nicolas Saenz Julienne <nsaenz@kernel.org>,
linux-arm-kernel@lists.infradead.org, linux-mmc@vger.kernel.org,
devicetree@vger.kernel.org,
bcm-kernel-feedback-list@broadcom.com,
linux-rpi-kernel@lists.infradead.org,
Rob Herring <robh+dt@kernel.org>
Cc: f.fainelli@gmail.com, phil@raspberrypi.com,
tim.gover@raspberrypi.com, adrian.hunter@intel.com,
sbranden@broadcom.com, alcooperx@gmail.com,
linux-kernel@vger.kernel.org, ulf.hansson@linaro.org
Subject: Re: [PATCH 4/4] ARM: dts: Fix-up EMMC2 controller's frequency
Date: Wed, 24 Mar 2021 16:34:09 +0100 [thread overview]
Message-ID: <78dec30c052e9bb76e52c38f3da5af371e5d65f5.camel@suse.de> (raw)
In-Reply-To: <401100ea-90ad-57b1-50da-967118a090da@i2se.com>
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Hi Stefan,
On Wed, 2021-03-24 at 16:16 +0100, Stefan Wahren wrote:
> Hi Nicolas,
>
> Am 22.03.21 um 19:58 schrieb Nicolas Saenz Julienne:
> > From: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
> >
> > Force emmc2's frequency to 150MHz as the default 100MHz (set by FW)
> > seems to interfere with the VPU clock when setup at frequencies bigger
> > than 500MHz (a pretty common case). This ends up causing unwarranted
> > SDHCI CMD hangs when no SD card is present.
> >
> > Signed-off-by: Nicolas Saenz Julienne <nsaenz@kernel.org>
> > ---
> > arch/arm/boot/dts/bcm2711-rpi-4-b.dts | 6 ++++++
> > 1 file changed, 6 insertions(+)
> >
> > diff --git a/arch/arm/boot/dts/bcm2711-rpi-4-b.dts b/arch/arm/boot/dts/bcm2711-rpi-4-b.dts
> > index 3b4ab947492a..9aa8408d9960 100644
> > --- a/arch/arm/boot/dts/bcm2711-rpi-4-b.dts
> > +++ b/arch/arm/boot/dts/bcm2711-rpi-4-b.dts
> > @@ -257,6 +257,12 @@ &emmc2 {
> > vqmmc-supply = <&sd_io_1v8_reg>;
> > vmmc-supply = <&sd_vcc_reg>;
> > broken-cd;
> > + /*
> > + * Force the frequency to 150MHz as the default 100MHz seems to
> > + * interfere with the VPU clock when setup at frequencies bigger than
> > + * 500MHz, causing unwarranted CMD hangs.
> > + */
> > + clock-frequency = <150000000>;
>
> i don't want to bike-shed here, but is there any chance to solve this in
> clk-bcm2835 in a less hacky way?
What do you have in mind?
All I can think of is adding some kind of heuristic to the clock's prepare()
callback. That said, I don't feel it would be a better solution than this.
Regards,
Nicolas
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next prev parent reply other threads:[~2021-03-24 15:35 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-22 18:58 [PATCH 0/4] BCM2711's sdhci-iproc CMD timeouts Nicolas Saenz Julienne
2021-03-22 18:58 ` [PATCH 1/4] dt-bindings: mmc: iproc-sdhci: Convert to json-schema Nicolas Saenz Julienne
2021-03-22 19:11 ` Scott Branden
2021-03-22 19:16 ` Nicolas Saenz Julienne
2021-03-23 21:08 ` Rob Herring
2021-03-23 21:24 ` Nicolas Saenz Julienne
2021-03-24 16:27 ` Scott Branden
2021-03-24 16:35 ` Nicolas Saenz Julienne
2021-03-24 16:43 ` Scott Branden
2021-03-23 20:16 ` Rob Herring
2021-03-22 18:58 ` [PATCH 2/4] dt-bindings: mmc: iproc-sdhci: Add clock-frequency support Nicolas Saenz Julienne
2021-03-27 17:14 ` Rob Herring
2021-03-22 18:58 ` [PATCH 3/4] mmc: sdhci-iproc: Set clock frequency as per DT Nicolas Saenz Julienne
2021-03-22 18:58 ` [PATCH 4/4] ARM: dts: Fix-up EMMC2 controller's frequency Nicolas Saenz Julienne
2021-03-22 19:06 ` Scott Branden
2021-03-22 19:17 ` Nicolas Saenz Julienne
2021-03-24 15:16 ` Stefan Wahren
2021-03-24 15:34 ` Nicolas Saenz Julienne [this message]
2021-03-25 19:11 ` Stefan Wahren
2021-03-26 16:17 ` Nicolas Saenz Julienne
2021-03-26 16:42 ` Stefan Wahren
2021-04-01 15:23 ` Alan Cooper
2021-04-05 8:45 ` Nicolas Saenz Julienne
2021-04-07 20:37 ` Alan Cooper
2021-04-09 9:28 ` Nicolas Saenz Julienne
2021-04-09 10:54 ` Nicolas Saenz Julienne
2021-04-09 18:28 ` Stefan Wahren
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