[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <YYLk0dEKX2Jlq0Se@lunn.ch>
Date: Wed, 3 Nov 2021 20:36:49 +0100
From: Andrew Lunn <andrew@...n.ch>
To: Grygorii Strashko <grygorii.strashko@...com>
Cc: "Russell King (Oracle)" <linux@...linux.org.uk>,
"David S. Miller" <davem@...emloft.net>, netdev@...r.kernel.org,
Jakub Kicinski <kuba@...nel.org>,
Heiner Kallweit <hkallweit1@...il.com>,
Florian Fainelli <f.fainelli@...il.com>,
linux-kernel@...r.kernel.org, Vignesh Raghavendra <vigneshr@...com>
Subject: Re: [RFC PATCH] net: phy/mdio: enable mmd indirect access through
phy_mii_ioctl()
On Wed, Nov 03, 2021 at 08:42:07PM +0200, Grygorii Strashko wrote:
>
>
> On 03/11/2021 02:27, Andrew Lunn wrote:
> > > > What i find interesting is that you and the other resent requester are
> > > > using the same user space tool. If you implement C45 over C22 in that
> > > > tool, you get your solution, and it will work for older kernels as
> > > > well. Also, given the diverse implementations of this IOTCL, it
> > > > probably works for more drivers than just those using phy_mii_ioctl().
> > >
> > > Do you mean change uapi, like
> > > add mdio_phy_id_is_c45_over_c22() and
> > > flag #define MDIO_PHY_ID_C45_OVER_C22 0x4000?
> >
> > No, i mean user space implements C45 over C22. Make phytool write
> > MII_MMD_CTRL and MII_MMD_DATA to perform a C45 over C22.
>
> Now I give up - as mentioned there is now way to sync User space vs Kernel
> MMD transactions and so no way to get trusted results.
Except that it will probably work 99% of the time, which is enough for
a debug tool. phylib is pretty idle most of the time, it just polls
the PHY once a second to see if the link status has changed. And does
not poll at all if interrupts are wired up. And you can always do a
read three times and see if you get the same answer, or do a write
followed by a read to see if the write actually happened correctly, or
corrupted some other register.
Andrew
Powered by blists - more mailing lists