linux-kernel - Re: [PATCH v6 2/2] EDAC/zynqmp: Add EDAC support for Xilinx ZynqMP OCM

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Message-ID: <Y2vsrDMrGSW0ZPv6@zn.tnic>
Date:   Wed, 9 Nov 2022 19:08:44 +0100
From:   Borislav Petkov <bp@...en8.de>
To:     "Potthuri, Sai Krishna" <sai.krishna.potthuri@....com>,
        "Datta, Shubhrajyoti" <shubhrajyoti.datta@....com>
Cc:     Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Michal Simek <michal.simek@...inx.com>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        Tony Luck <tony.luck@...el.com>,
        James Morse <james.morse@....com>,
        Robert Richter <rric@...nel.org>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-edac@...r.kernel.org" <linux-edac@...r.kernel.org>,
        "saikrishna12468@...il.com" <saikrishna12468@...il.com>,
        "git (AMD-Xilinx)" <git@....com>, kernel test robot <lkp@...el.com>
Subject: Re: [PATCH v6 2/2] EDAC/zynqmp: Add EDAC support for Xilinx ZynqMP
 OCM

On Wed, Nov 09, 2022 at 11:21:41AM +0000, Potthuri, Sai Krishna wrote:
> > On Wed, Nov 02, 2022 at 12:36:55PM +0530, Sai Krishna Potthuri wrote:
> > > Add EDAC support for Xilinx ZynqMP OCM Controller, this driver
> > 
> > So a while ago you said that this driver is for the on chip memory controller.
> > Is it possible for such a system to have another memory controller too for
> > which another EDAC driver gets loaded?
> > 
> > Because the EDAC core - at least on x86 - assumes that a single driver runs on
> > the system and I don't think I've ever had the case where we need multiple
> > drivers. And in such case to audit it for concurrency issues.
> > 
> > So I guess the question is, can a system have zynqmp_ocm_edac and say,
> > synopsys_edac or some other EDAC driver loaded at the same time?
> Yes, we have this scenario on Xilinx ZynqMP platform where we have both
> the drivers (zynqmp_ocm_edac - OCM Controller and synopsys_edac - DDR
> Memory Controller) probed at the same time.

Ok, Shubhrajyoti is on Cc too. I asked him the same question - what the
possible drivers configuration would be and he gave me:

Platform	| Drivers / Controllers	|
------------------------------------------------------------ 
 ZynqMP	| Synopsys and OCM	|
Versal		| DDRMC and OCM	|

The ZynqMP platform needs Synopsys which is, let's say for simplicity,
the main EDAC driver using edac_mc* etc.

Looking at the patches, Versal is similar and uses the same APIs.

OCM uses the edac_device* stuff so that should be ok. I say "should"
because, again, I haven't played with multiple EDAC drivers system. But
we'll see where that gets us.

Ok, I guess architecture-wise this looks ok, I'll review the drivers
later and we'll see.

Thx.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette