From: Geert Uytterhoeven <geert@linux-m68k.org>
To: Andrew Lunn <andrew@lunn.ch>,
Heiner Kallweit <hkallweit1@gmail.com>,
Russell King <linux@armlinux.org.uk>
Cc: Biju Das <biju.das.jz@bp.renesas.com>,
Florian Fainelli <f.fainelli@gmail.com>,
Adam Ford <aford173@gmail.com>,
Grygorii Strashko <grygorii.strashko@ti.com>,
Linux-Renesas <linux-renesas-soc@vger.kernel.org>,
Linux ARM <linux-arm-kernel@lists.infradead.org>,
netdev <netdev@vger.kernel.org>,
"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS"
<devicetree@vger.kernel.org>,
Geert Uytterhoeven <geert+renesas@glider.be>
Subject: Re: [PATCH 0/9] renesas: Add compatible properties to Ethernet PHY nodes
Date: Thu, 23 Sep 2021 13:00:11 +0200 [thread overview]
Message-ID: <CAMuHMdU6Mrfina3+2iW+RKaujk57JSRtmixRPn1b0d2w5dZ3eA@mail.gmail.com> (raw)
In-Reply-To: <cover.1631174218.git.geert+renesas@glider.be>
On Thu, Sep 9, 2021 at 10:49 AM Geert Uytterhoeven
<geert+renesas@glider.be> wrote:
> If an Ethernet PHY reset is asserted when the Ethernet driver is
> initialized, the PHY cannot be probed:
>
> mdio_bus ee700000.ethernet-ffffffff: MDIO device at address 1 is missing
>
> This happens because the Linux PHY subsystem tries to read the PHY
> Identifier registers before handling PHY reset. Hence if the PHY reset
> was asserted before, identification fails.
>
> An easy way to reproduce this issue is by using kexec to launch a new
> kernel (the PHY reset will be asserted before starting the new kernel),
> or by unbinding and rebinding the Ethernet driver (the PHY reset will be
> asserted during unbind), e.g. on koelsch:
>
> echo ee700000.ethernet > /sys/bus/platform/drivers/sh-eth/unbind
> $ echo ee700000.ethernet > /sys/bus/platform/drivers/sh-eth/bind
>
> The recommended approach[1][2] seems to be working around this issue by
> adding compatible values to all ethernet-phy nodes, so Linux can
> identify the PHY at any time, without reading the PHY ID from the
> device, and regardless of the state of the PHY reset line.
>
> Hence this patch series adds such compatible values to all Ethernet PHY
> subnodes representing PHYs on all boards with Renesas ARM and ARM64
> SoCs. For easier review, I have split the series in one patch per PHY
> model.
>
> On most boards, I could verify the actual PHY ID at runtime[3], on other
> boards I had to resort to schematics.
>
> Kexec and Ethernet driver rebind have been tested on Koelsch and
> Salvator-XS.
>
> I plan to queue these in renesas-devel for v5.16.
>
> Thanks for your comments!
I'd be very grateful for comments (e.g. Acked-by) from the Ethernet
PHY people.
Thanks again!
> [1] "Re: [PATCH] RFC: net: phy: of phys probe/reset issue"
> https://lore.kernel.org/r/ade12434-adf2-6ea7-24ce-ce45ad2e1b5e@gmail.com/
> [2] "PHY reset may still be asserted during MDIO probe"
> https://lore.kernel.org/r/CAMuHMdXno2OUHqsAfO0z43JmGkFehD+FJ2dEjEsr_P53oAAPxA@mail.gmail.com
> [3] The easiest way to obtain the PHY ID is by adding a debug print to
> drivers/net/phy/phy_device.c:get_phy_c22_id(), _before_ applying
> this patch.
>
> Geert Uytterhoeven (9):
> ARM: dts: renesas: Add compatible properties to KSZ8041 Ethernet PHYs
> ARM: dts: renesas: Add compatible properties to KSZ8081 Ethernet PHYs
> ARM: dts: renesas: Add compatible properties to KSZ9031 Ethernet PHYs
> iARM: dts: renesas: Add compatible properties to LAN8710A Ethernet
> PHYs
> ARM: dts: renesas: Add compatible properties to RTL8201FL Ethernet
> PHYs
> ARM: dts: renesas: Add compatible properties to uPD6061x Ethernet PHYs
> arm64: dts: renesas: Add compatible properties to AR8031 Ethernet PHYs
> arm64: dts: renesas: Add compatible properties to KSZ9031 Ethernet
> PHYs
> arm64: dts: renesas: Add compatible properties to RTL8211E Ethernet
> PHYs
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
next prev parent reply other threads:[~2021-09-23 11:00 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-09 8:49 [PATCH 0/9] renesas: Add compatible properties to Ethernet PHY nodes Geert Uytterhoeven
2021-09-09 8:49 ` [PATCH 1/9] ARM: dts: renesas: Add compatible properties to KSZ8041 Ethernet PHYs Geert Uytterhoeven
2021-09-09 8:49 ` [PATCH 2/9] ARM: dts: renesas: Add compatible properties to KSZ8081 " Geert Uytterhoeven
2021-09-09 8:49 ` [PATCH 3/9] ARM: dts: renesas: Add compatible properties to KSZ9031 " Geert Uytterhoeven
2021-09-23 11:41 ` Biju Das
2021-09-09 8:49 ` [PATCH 4/9] iARM: dts: renesas: Add compatible properties to LAN8710A " Geert Uytterhoeven
2021-09-09 8:49 ` [PATCH 5/9] ARM: dts: renesas: Add compatible properties to RTL8201FL " Geert Uytterhoeven
2021-09-09 8:49 ` [PATCH 6/9] ARM: dts: renesas: Add compatible properties to uPD6061x " Geert Uytterhoeven
2021-09-09 8:49 ` [PATCH 7/9] arm64: dts: renesas: Add compatible properties to AR8031 " Geert Uytterhoeven
2021-09-09 8:49 ` [PATCH 8/9] arm64: dts: renesas: Add compatible properties to KSZ9031 " Geert Uytterhoeven
2021-09-28 7:40 ` Geert Uytterhoeven
2021-09-09 8:49 ` [PATCH 9/9] arm64: dts: renesas: Add compatible properties to RTL8211E " Geert Uytterhoeven
2021-09-23 11:38 ` Biju Das
2021-09-23 11:00 ` Geert Uytterhoeven [this message]
2021-09-23 14:09 ` [PATCH 0/9] renesas: Add compatible properties to Ethernet PHY nodes Andrew Lunn
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