Re: [PATCH 2/2] clk: mvebu: cp110 add CLK_IGNORE_UNUSED to pcie_x10, pcie_x11 & pcie_x4

[Gregory CLEMENT <gregory.clement@bootlin.com>]

Josua Mayer <josua@solid-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@lunn.ch>


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

Thanks,

Gregory


>>
>>     Andrew

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