From: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
To: 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
Cc: f.fainelli@gmail.com, tim.gover@raspberrypi.com,
sbranden@broadcom.com, alcooperx@gmail.com,
adrian.hunter@intel.com, linux-kernel@vger.kernel.org,
phil@raspberrypi.com,
Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Subject: [RFC 0/2] sdhci-iproc CMD timeouts
Date: Thu, 25 Feb 2021 10:52:14 +0100 [thread overview]
Message-ID: <20210225095216.28591-1-nsaenzjulienne@suse.de> (raw)
I'm seeing a rather odd behavior from sdhci-iproc's integration in BCM2711
(Raspberry Pi 4's SoC), and would appreciate some opinions.
The controller will timeout on SDHCI CMDs under the following conditions:
- No SD card plugged in (the card polling thread is running, CD irq disabled).
- BCM2711's VPU clock[1] configured at 500MHz or more, lower clocks are OK.
There is no specific command that will time out, it seems random.
Here's what I found out. The SDHCI controller runs at 100MHz, by bumping the
frequency to 150MHz the issue disapears. Might be pure luck, or maybe I hit the
nail and it's proper interference. Can't say.
Regards,
Nicolas
---
[1] For those who are not aware, here's the relationship between VPU's clock
and emmc2's:
osc 54000000
plld 3000000091
plld_per 750000023
emmc2 149882908
pllc 2999999988
pllc_core0 999999996
vpu 499999998
Nicolas Saenz Julienne (2):
ARM: dts: Fix-up EMMC2 controller's frequency
mmc: sdhci-iproc: Set clock frequency as per DT
arch/arm/boot/dts/bcm2711-rpi-4-b.dts | 6 ++++++
drivers/mmc/host/sdhci-iproc.c | 10 ++++++++++
2 files changed, 16 insertions(+)
--
2.30.1
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next reply other threads:[~2021-02-25 9:53 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-25 9:52 Nicolas Saenz Julienne [this message]
2021-02-25 9:52 ` [RFC 1/2] ARM: dts: Fix-up EMMC2 controller's frequency Nicolas Saenz Julienne
2021-02-25 9:52 ` [RFC 2/2] mmc: sdhci-iproc: Set clock frequency as per DT Nicolas Saenz Julienne
2021-03-09 8:14 ` [RFC 0/2] sdhci-iproc CMD timeouts Ulf Hansson
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