netdev - Re: Marvell phy errata origins?

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Message-ID: <3c16d944-9874-d016-e3f1-68055a22c173@cisco.com>
Date:   Tue, 18 Apr 2017 07:18:03 -0700
From:   Daniel Walker <danielwa@...co.com>
To:     Andrew Lunn <andrew@...n.ch>
Cc:     Florian Fainelli <f.fainelli@...il.com>,
        Andy Fleming <afleming@...escale.com>,
        Harini Katakam <harini.katakam@...inx.com>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        HEMANT RAMDASI <hramdasi@...co.com>,
        "Julius Hemanth Pitti -X (jpitti - MONTA VISTA SOFTWARE INC at Cisco)" 
        <jpitti@...co.com>
Subject: Re: Marvell phy errata origins?

On 04/18/2017 07:04 AM, Andrew Lunn wrote:
> On Tue, Apr 18, 2017 at 06:16:33AM -0700, Daniel Walker wrote:
>> Hi,
>>
>> Cisco is using a Marvell 88E1112 phy. It seems to be fairly similar
>> to the 88E1111 which Harini added a fix for.
> Hi Daniel
>
> If you look at Marvell reference drive, DSDT, they are actually quite
> different. Different virtual cable tester, different downshift
> configuration, different packet generator, different loopback. I would
> say they are different generations of PHY.

Ok .

>
>> In Harini's commit
>> message for ,
>>
>> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/drivers/net/phy/marvell.c?id=3ec0a0f10ceb
>>
>> "This function has a sequence accessing Page 5 and Register 31, both
>> of which are not defined or reserved for this PHY"
>>
>> For the 88E1112 we see that these are "Factory Test Modes" which the
>> contents of are not documented. They aren't really "not defied", and
>> aren't really "reserved" .. Marvell support claims they don't
>> support these drivers, and Freescale seems to be adding these
>> drivers, and the line we are looking at.
>>
>> We had some issues with our PHY which were corrected with the same
>> patch Harini used but modified for the M88E1112. We're trying to get
>> to the bottom of where this code came from and what it was suppose
>> to be doing.
> I tried to find this errata fix in the Marvell reference code. And
> failed to find it. But it is "Vendor Crap" code, hard to find anything
> in it.
>
> My guess is, this errata just applies to one model of PHY, maybe even
> one revision of one model of a PHY. The hard bit is figuring out what
> actually needs it. Do you have access to Marvell datasheets?

Prior to Andy's commit this code was duplicated in at least a couple of 
the ethernet drivers from Freescale. I think all Andy did was combine 
them all.

I think the data sheet is here for the 1112,

http://www.dexsilicium.com/Marvell_88E1112.pdf

This is what I've been using. My contact with Marvell for support is 
minimal. Andy's email at Freescale bounced , so maybe someone else form 
Freescale could comment. There must have been something very strange 
getting fixed due to using unnamed hex values in the code.

Daniel