linux-kernel - Re: [PATCH 1/3] dt-bindings: spi: Update clocks property for ARM pl022

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: <25913b62-7d55-1118-34dd-f7662adef019@arm.com>
Date:   Mon, 28 Feb 2022 16:01:45 +0000
From:   Robin Murphy <robin.murphy@....com>
To:     Mark Brown <broonie@...nel.org>
Cc:     Kuldeep Singh <singh.kuldeep87k@...il.com>,
        linux-arm-kernel@...ts.infradead.org, linux-spi@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        Rob Herring <robh+dt@...nel.org>,
        Linus Walleij <linus.walleij@...aro.org>
Subject: Re: [PATCH 1/3] dt-bindings: spi: Update clocks property for ARM
 pl022

On 2022-02-28 15:46, Mark Brown wrote:
> On Mon, Feb 28, 2022 at 03:27:08PM +0000, Robin Murphy wrote:
>> On 2022-02-28 15:11, Mark Brown wrote:
> 
>>> Well, it could also be that the clock is wired to some other clock which
>>> is always on (which I guess is why the driver allows this in the first
>>> place, there's a lot of sloppy code around stuff like that in the tree).
> 
>> I wouldn't say the driver "allows" it, so much as it just blindly grabs the
>> first clock assuming it's SSPCLK per the binding, and thus it will happen to
>> work out if the underlying physical clock is the same as, or equivalent to,
>> the APB PCLK. Otherwise, it's already into some degree of not working
>> properly, by virtue of reading the wrong clock rate.
> 
> Ah, the APB clock requirement is inherited from the AMBA implementation
> isn't it?  We really ought to be extending an AMBA binding here...

Yup, both the "apb_pclk" clock specifier and the "arm,primecell" 
compatible technically belong to the common AMBA binding, but I'm not 
sure whether schema has the ability to compose at such fine-grained a 
level :/

Robin.