linux-kernel - Re: [PATCH v6] edac: synps: Added EDAC support for zynq ddr ecc controller

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Message-ID: <CAGnW=BZO0Aj1yFJEXc0sZzo1Ym518d_Ges6pRkZsTuSdpWk+-w@mail.gmail.com>
Date:	Tue, 2 Dec 2014 16:47:31 +0530
From:	punnaiah choudary kalluri <punnaia@...inx.com>
To:	Borislav Petkov <bp@...en8.de>
Cc:	Punnaiah Choudary Kalluri <punnaiah.choudary.kalluri@...inx.com>,
	dougthompson@...ssion.com,
	"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
	"linux-doc@...r.kernel.org" <linux-doc@...r.kernel.org>,
	linux-arm-kernel@...ts.infradead.org,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	linux-edac@...r.kernel.org,
	"michal.simek@...inx.com" <michal.simek@...inx.com>,
	"robh+dt@...nel.org" <robh+dt@...nel.org>,
	"pawel.moll@....com" <pawel.moll@....com>,
	"mark.rutland@....com" <mark.rutland@....com>,
	"ijc+devicetree@...lion.org.uk" <ijc+devicetree@...lion.org.uk>,
	Kumar Gala <galak@...eaurora.org>,
	Rob Landley <rob@...dley.net>,
	Punnaiah Choudary <kpc528@...il.com>
Subject: Re: [PATCH v6] edac: synps: Added EDAC support for zynq ddr ecc controller

On Tue, Dec 2, 2014 at 4:06 PM, Borislav Petkov <bp@...en8.de> wrote:
> On Tue, Dec 02, 2014 at 10:51:22AM +0530, punnaiah choudary kalluri wrote:
>> >> +/**
>> >> + * synps_edac_get_eccstate - Return the controller ecc enable/disable status
>> >> + * @base:    Pointer to the ddr memory contoller base address
>> >> + *
>> >> + * This routine returns the ECC enable/disable status for the controller
>> >> + *
>> >> + * Return: a ecc status boolean i.e true/false - enabled/disabled.
>> >> + */
>> >> +static bool synps_edac_get_eccstate(void __iomem *base)
>> >> +{
>> >> +     enum dev_type dt;
>> >> +     u32 ecctype;
>> >> +     bool state = false;
>> >> +
>> >> +     dt = synps_edac_get_dtype(base);
>> >> +     if (dt == DEV_UNKNOWN)
>> >> +             return state;
>> >> +
>> >> +     ecctype = readl(base + SCRUB_OFST) & SCRUB_MODE_MASK;
>> >> +
>> >> +     if ((ecctype == SCRUB_MODE_SECDED) && (dt == DEV_X2)) {
>> >> +             state = true;
>> >> +             writel(0x0, base + ECC_CTRL_OFST);
>> >
>> > Out of curiosity, why is that register write needed here? Maybe
>> > forgotten? It looks unbalanced...
>>
>> This is needed to start capturing the correctable and uncorrectable errors.
>> Writing 1 to this register bits will clear the counters and writing 0 will start
>> the counters.
>
> So this definitely doesn't belong here then.
>
> It should be the *last* thing you do after having initialized the whole
> driver entirely and successfully and you're ready to start logging
> errors.
>
> Now you're calling it in synps_edac_mc_probe() so the counters will
> start before you have even initialized the rest of the driver.
>
> What is worse, if one of those things you do on the init path fails, you
> enter prematurely and the counters are still running. Not good.

Understood. thanks.

>
>> It is crossing 80 cols. so, there is line break here. I feel the other
>> way as the check patch throws warning for this.
>
> And I'm saying you shouldn't follow checkpatch to the letter and think
> for yourself instead.
>
> What do you think is more readable?

Definitely the second one :). I will update accordingly

Thanks,
Punnaiah

>
> This:
>
>                        dimm = csi->channels[j]->dimm;
>                        dimm->edac_mode = EDAC_FLAG_SECDED;
>                        dimm->mtype = synps_edac_get_mtype(priv->baseaddr);
>                        dimm->nr_pages =
>                            (size >> PAGE_SHIFT) / csi->nr_channels;
>                        dimm->grain = SYNPS_EDAC_ERR_GRAIN;
>                        dimm->dtype = synps_edac_get_dtype(priv->baseaddr);
>
> or this:
>
>                        dimm             = csi->channels[j]->dimm;
>                        dimm->mtype      = synps_edac_get_mtype(priv->baseaddr);
>                        dimm->grain      = SYNPS_EDAC_ERR_GRAIN;
>                        dimm->dtype      = synps_edac_get_dtype(priv->baseaddr);
>                        dimm->nr_pages   = (size >> PAGE_SHIFT) / csi->nr_channels;
>                        dimm->edac_mode  = EDAC_FLAG_SECDED;
>
> --
> Regards/Gruss,
>     Boris.
>
> Sent from a fat crate under my desk. Formatting is fine.
> --
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