linux-kernel - Re: [PATCH 2/2] clk: mvebu: cp110 add CLK_IGNORE_UNUSED to pcie_x10, pcie_x11 & pcie

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <87ldkermte.fsf@BLaptop.bootlin.com>
Date: Mon, 10 Nov 2025 15:20:45 +0100
From: Gregory CLEMENT <gregory.clement@...tlin.com>
To: Josua Mayer <josua@...id-run.com>, Andrew Lunn <andrew@...n.ch>
Cc: Sebastian Hesselbarth <sebastian.hesselbarth@...il.com>, Rob Herring
 <robh@...nel.org>, Krzysztof
 Kozlowski <krzk+dt@...nel.org>, Conor Dooley <conor+dt@...nel.org>, Michael
 Turquette <mturquette@...libre.com>, Stephen Boyd <sboyd@...nel.org>,
 Rabeeh
 Khoury <rabeeh@...id-run.com>, Yazan Shhady <yazan.shhady@...id-run.com>,
 Mikhail Anikin <mikhail.anikin@...id-run.com>, Jon Nettleton
 <jon@...id-run.com>, "linux-arm-kernel@...ts.infradead.org"
 <linux-arm-kernel@...ts.infradead.org>, "devicetree@...r.kernel.org"
 <devicetree@...r.kernel.org>, "linux-kernel@...r.kernel.org"
 <linux-kernel@...r.kernel.org>, "linux-clk@...r.kernel.org"
 <linux-clk@...r.kernel.org>
Subject: Re: [PATCH 2/2] clk: mvebu: cp110 add CLK_IGNORE_UNUSED to
 pcie_x10, pcie_x11 & pcie_x4

Josua Mayer <josua@...id-run.com> writes:

> I missed a colon in the subject line "cp110:",
> should I roll v2 for this?

it is up to the clock maintainer.

>
> Am 30.10.25 um 16:33 schrieb Andrew Lunn:
>> On Thu, Oct 30, 2025 at 04:16:26PM +0100, Josua Mayer wrote:
>>> CP110 based platforms rely on the bootloader for pci port
>>> initialization.
>>> TF-A actively prevents non-uboot re-configuration of pci lanes, and many
>>> boards do not have software control over the pci card reset.
>>>
>>> If a pci port had link at boot-time and the clock is stopped at a later
>>> point, the link fails and can not be recovered.
>>>
>>> PCI controller driver probe - and by extension ownership of a driver for
>>> the pci clocks - may be delayed especially on large modular kernels,
>>> causing the clock core to start disabling unused clocks.
>>>
>>> Add the CLK_IGNORE_UNUSED flag to the three pci port's clocks to ensure
>>> they are not stopped before the pci controller driver has taken
>>> ownership and tested for an existing link.
>>>
>>> This fixes failed pci link detection when controller driver probes late,
>>> e.g. with arm64 defconfig and CONFIG_PHY_MVEBU_CP110_COMPHY=m.
>> Seems like a reasonable compromise, given that TF-A could be classed
>> as broken. This must also prevent suspend/resume powering off PCI
>> devices, and then reconnecting them on resume.
> Currently pcie-armada8k (unlike e.g. pci-imx6) does not currently define
> any dev_pm_ops - so we should be safe from any power-management.
>>
>> Reviewed-by: Andrew Lunn <andrew@...n.ch>


Acked-by: Gregory CLEMENT <gregory.clement@...tlin.com>

Thanks,

Gregory


>>
>>     Andrew

-- 
Grégory CLEMENT, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com