linux-kernel - Re: [PATCH] dt-bindings: rtc: zynqmp: Describe power-domains property

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: <202402192019160b9c4120@mail.local>
Date: Mon, 19 Feb 2024 21:19:16 +0100
From: Alexandre Belloni <alexandre.belloni@...tlin.com>
To: Michal Simek <michal.simek@....com>
Cc: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>,
	linux-kernel@...r.kernel.org, monstr@...str.eu,
	michal.simek@...inx.com, git@...inx.com,
	Conor Dooley <conor+dt@...nel.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
	Rob Herring <robh@...nel.org>,
	"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" <devicetree@...r.kernel.org>,
	"moderated list:ARM/ZYNQ ARCHITECTURE" <linux-arm-kernel@...ts.infradead.org>,
	"open list:REAL TIME CLOCK (RTC) SUBSYSTEM" <linux-rtc@...r.kernel.org>
Subject: Re: [PATCH] dt-bindings: rtc: zynqmp: Describe power-domains property

On 19/02/2024 14:11:50+0100, Michal Simek wrote:
> 
> 
> On 2/17/24 09:26, Krzysztof Kozlowski wrote:
> > On 16/02/2024 10:42, Michal Simek wrote:
> > > 
> > > 
> > > On 2/16/24 10:19, Krzysztof Kozlowski wrote:
> > > > On 16/02/2024 09:51, Michal Simek wrote:
> > > > > RTC has its own power domain on Xilinx Versal SOC that's why describe it as
> > > > > optional property.
> > > > > 
> > > > > Signed-off-by: Michal Simek <michal.simek@....com>
> > > > > ---
> > > > > 
> > > > >    Documentation/devicetree/bindings/rtc/xlnx,zynqmp-rtc.yaml | 3 +++
> > > > >    1 file changed, 3 insertions(+)
> > > > > 
> > > > 
> > > > But Versal is not described in this binding, is it? I see only one
> > > > compatible.
> > > 
> > > It is the same IP only as is on zynqmp with own power rail.
> > 
> > Then you should have separate compatible, because they are not
> > identical. It would also allow you to narrow the domains to versal and
> > also require it (on versal).
> 
> I can double check with HW guys but I am quite sure IP itself is exactly the
> same. What it is different is that there is own power domain to it (not
> shared one as is in zynqmp case).
> 
> Also Linux is non secure sw and if secure firmware won't allow to change
> setting of it it can't be required. I am just saying that Linux doesn't need
> to be owner of any power domain that's why it shouldn't be required
> property.

I guess because the integration is different, you still need a
differente compatible so you can forbid the property on non-Versal.

> 
> Thanks,
> Michal

-- 
Alexandre Belloni, co-owner and COO, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com