Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
MIME-Version: 1.0
References: <20230809214946.18975-1-luke.lu@libre.computer> <2cdc67aa-6029-7231-76a8-54c6b51b066c@gmail.com>
In-Reply-To: <2cdc67aa-6029-7231-76a8-54c6b51b066c@gmail.com>
From:   Da Xue <da@libre.computer>
Date:   Fri, 11 Aug 2023 04:45:26 -0400
Message-ID: <CACqvRUYUkeU9C_W47yPLSRb=+VL4Hti1+E2YQNLKQtcXw_H-OQ@mail.gmail.com>
Subject: Re: [PATCH net v4] net: phy: meson-gxl: implement meson_gxl_phy_resume()
To:     Heiner Kallweit <hkallweit1@gmail.com>
Cc:     Luke Lu <luke.lu@libre.computer>, Andrew Lunn <andrew@lunn.ch>,
        Russell King <linux@armlinux.org.uk>,
        "David S . Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        Neil Armstrong <neil.armstrong@linaro.org>,
        Kevin Hilman <khilman@baylibre.com>,
        Jerome Brunet <jbrunet@baylibre.com>,
        Martin Blumenstingl <martin.blumenstingl@googlemail.com>,
        Florian Fainelli <f.fainelli@gmail.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        netdev@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-amlogic@lists.infradead.org, linux-kernel@vger.kernel.org,
        Da Xue <da@libre.computer>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
Precedence: bulk

On Fri, Aug 11, 2023 at 2:07=E2=80=AFAM Heiner Kallweit <hkallweit1@gmail.c=
om> wrote:
>
> On 09.08.2023 23:49, Luke Lu wrote:
> > From: Da Xue <da@libre.computer>
> >
> > While testing the suspend/resume function, we found the ethernet
> > is broken if using internal PHY of Amlogic meson GXL SoC.
> > After system resume back, the ethernet is down, no carrier found.
> >
> >       eth0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc mq state
> >               DOWN group default qlen 1000
> >
> > In this patch, we re-initialize the internal PHY to fix this problem.
> >
>
> It's not an unusual case that system cuts power to the PHY during
> system suspend. So the PHY needs to be re-initialized on resume.
> That's why we call phy_init_hw() in mdio_bus_phy_resume().

Thanks for the review, Heiner.

We will rework this in v5.

>
> If going your way we would be better off calling .config_init()
> in genphy_resume(). Please check the MAC driver, maybe it's better
> to re-initialize the PHY in the resume path of the MAC driver.
>
> >       eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state U=
P
> >               group default qlen 1000
> >
> > Fixes: 7334b3e47aee ("net: phy: Add Meson GXL Internal PHY driver")
> > Signed-off-by: Da Xue <da@libre.computer>
> > Signed-off-by: Luke Lu <luke.lu@libre.computer>
> >
> > ---
> > Note, we don't Cc stable kernel tree in this patch intentionally, since
> > there will be a cherry-pick failure if apply this patch from kernel ver=
sion
> > less than v6.2, it's not a logic failure but due to the changes too clo=
se.
> >
> > Please check commit 69ff53e4a4c9 ("net: phy: meson-gxl: use MMD access =
dummy stubs for GXL, internal PHY")
> > We plan to slightly rework the patch, and send it to stable tree separa=
tely
> > once this patch is accepted into mainline.
> >
> > v4:
> >  - refactor commit message to better explain the problem & fix
> >  - check return value of genphy_resume()
> >  - add 'net' annotation
> >  - add Fixes tag
> >
> > v3: https://lore.kernel.org/netdev/20230808050016.1911447-1-da@libre.co=
mputer
> >  - fix missing parameter of genphy_resume()
> >
> > v2: https://lore.kernel.org/netdev/20230804201903.1303713-1-da@libre.co=
mputer
> >  - call generic genphy_resume()
> >
> > v1: https://lore.kernel.org/all/CACqvRUZRyXTVQyy9bUviQZ+_moLQBjPc6nin_N=
QC+CJ37yNnLw@mail.gmail.com
> > ---
> >  drivers/net/phy/meson-gxl.c | 17 ++++++++++++++++-
> >  1 file changed, 16 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/net/phy/meson-gxl.c b/drivers/net/phy/meson-gxl.c
> > index bb9b33b6bce2..9ebe09b0cd8c 100644
> > --- a/drivers/net/phy/meson-gxl.c
> > +++ b/drivers/net/phy/meson-gxl.c
> > @@ -132,6 +132,21 @@ static int meson_gxl_config_init(struct phy_device=
 *phydev)
> >       return 0;
> >  }
> >
> > +static int meson_gxl_phy_resume(struct phy_device *phydev)
> > +{
> > +     int ret;
> > +
> > +     ret =3D genphy_resume(phydev);
> > +     if (ret)
> > +             return ret;
> > +
> > +     ret =3D meson_gxl_config_init(phydev);
> > +     if (ret)
> > +             return ret;
> > +
> > +     return 0;
> > +}
> > +
> >  /* This function is provided to cope with the possible failures of thi=
s phy
> >   * during aneg process. When aneg fails, the PHY reports that aneg is =
done
> >   * but the value found in MII_LPA is wrong:
> > @@ -196,7 +211,7 @@ static struct phy_driver meson_gxl_phy[] =3D {
> >               .config_intr    =3D smsc_phy_config_intr,
> >               .handle_interrupt =3D smsc_phy_handle_interrupt,
> >               .suspend        =3D genphy_suspend,
> > -             .resume         =3D genphy_resume,
> > +             .resume         =3D meson_gxl_phy_resume,
> >               .read_mmd       =3D genphy_read_mmd_unsupported,
> >               .write_mmd      =3D genphy_write_mmd_unsupported,
> >       }, {
>