From: Stefan Wahren <stefan.wahren@i2se.com>
To: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>,
Alan Cooper <alcooperx@gmail.com>,
Florian Fainelli <f.fainelli@gmail.com>,
Scott Branden <sbranden@broadcom.com>
Cc: Nicolas Saenz Julienne <nsaenz@kernel.org>,
"moderated list:BROADCOM BCM7XXX ARM ARCHITECTURE"
<linux-arm-kernel@lists.infradead.org>,
linux-mmc <linux-mmc@vger.kernel.org>,
DTML <devicetree@vger.kernel.org>,
BCM Kernel Feedback <bcm-kernel-feedback-list@broadcom.com>,
linux-rpi-kernel@lists.infradead.org, phil@raspberrypi.com,
Tim Gover <tim.gover@raspberrypi.com>,
Adrian Hunter <adrian.hunter@intel.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Ulf Hansson <ulf.hansson@linaro.org>,
Rob Herring <robh+dt@kernel.org>
Subject: Re: [PATCH 4/4] ARM: dts: Fix-up EMMC2 controller's frequency
Date: Fri, 9 Apr 2021 20:28:59 +0200 [thread overview]
Message-ID: <6dfd1108-deaa-8606-01a9-4739e7c2da91@i2se.com> (raw)
In-Reply-To: <2dbb9e8c1f1e107712b05e36aa1b244329381425.camel@suse.de>
Hi Nicolas,
Am 09.04.21 um 12:54 schrieb Nicolas Saenz Julienne:
> Hi again,
>
> On Wed, 2021-04-07 at 16:37 -0400, Alan Cooper wrote:
>> Nicolas,
>>
>> I got a better description of the failure and it looks like the bus
>> clock needs to be limited to 300KHz for a 500MHz core clock.
>> What's happening is that an internal reset sequence is needed after a
>> command timeout and the reset signal needs to be asserted for at least
>> 2 ticks of the bus clock. This is done using a 12 bit counter clocked
>> by the core clock. That means a 500MHz core clock produces a 122KHz
>> reset signal which is too fast for 2 ticks of the 200KHz bus clock
>> (100KHz) but is okay for the 300KHz (150Khz) bus clock.
> Is there any value in implementing this in a generic way?
i don't have any idea which callback could manipulate the reset
duration. Limiting the min clk frequency looks like the less invasive
solution to me. Touching the DT isn't recommend.
Best regards
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prev parent reply other threads:[~2021-04-09 18:31 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
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 [this message]
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