linux-kernel - Re: [PATCH 0/4] scmi: Bypass set fwnode to address devlink issue

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: Windows password security audit tool. GUI, reports in PDF.

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

Message-ID: <20241230021238.GG28662@localhost.localdomain>
Date: Mon, 30 Dec 2024 10:12:39 +0800
From: Peng Fan <peng.fan@....nxp.com>
To: Linus Walleij <linus.walleij@...aro.org>
Cc: Saravana Kannan <saravanak@...gle.com>,
	Sudeep Holla <sudeep.holla@....com>,
	Cristian Marussi <cristian.marussi@....com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Dong Aisheng <aisheng.dong@....com>,
	Fabio Estevam <festevam@...il.com>, Shawn Guo <shawnguo@...nel.org>,
	Jacky Bai <ping.bai@....com>,
	Pengutronix Kernel Team <kernel@...gutronix.de>,
	Sascha Hauer <s.hauer@...gutronix.de>, arm-scmi@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
	linux-gpio@...r.kernel.org, imx@...ts.linux.dev,
	Peng Fan <peng.fan@....com>
Subject: Re: [PATCH 0/4] scmi: Bypass set fwnode to address devlink issue

On Fri, Dec 27, 2024 at 06:06:24PM +0100, Linus Walleij wrote:
>On Wed, Dec 25, 2024 at 9:21 AM Peng Fan (OSS) <peng.fan@....nxp.com> wrote:
>
>> Current scmi drivers not work well with devlink. This patchset is a
>> retry to address the issue in [1] which was a few months ago.
>>
>> Current scmi devices are not created from device tree, they are created
>> from a scmi_device_id entry of each driver with the protocol matches
>> with the fwnode reg value, this means there could be multiple devices created
>> for one fwnode, but the fwnode only has one device pointer.
>>
>> This patchset is to do more checking before setting the device fwnode.
>>
>> This may looks like hack, but seems no better way to make scmi works
>> well with devlink.
>>
>> [1]: https://lore.kernel.org/arm-scmi/CAGETcx8m48cy-EzP6_uoGN7KWsQw=CfZWQ-hNUzz_7LZ0voG8A@mail.gmail.com/
>
>Please drive any devlink-related patches by Saravana Kannan, he's pretty
>much the only person I trust to know how to do devlinks right.

Quote Saravana's conclution[1] here:
"The best fw_devlink could do is just not enforce any dependencies if
there is more than one device instantiated for a given supplier DT
node."

So I think for systems using scmi could not rely on devlink to build
supplier/consumer to make driver probe in order.

[1]https://lore.kernel.org/arm-scmi/CAGETcx8m48cy-EzP6_uoGN7KWsQw=CfZWQ-hNUzz_7LZ0voG8A@mail.gmail.com/

Thanks,
Peng
>
>Yours,
>Linus Walleij