netdev - Re: [PATCH v3 net-next] r8169: add support for rtl8168h(revid 0x2a) + rtl8211fs fiber application

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Date:   Tue, 23 Aug 2022 17:31:18 +0200
From:   Andrew Lunn <andrew@...n.ch>
To:     Hau <hau@...ltek.com>
Cc:     "hkallweit1@...il.com" <hkallweit1@...il.com>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        nic_swsd <nic_swsd@...ltek.com>,
        "kuba@...nel.org" <kuba@...nel.org>,
        "davem@...emloft.net" <davem@...emloft.net>
Subject: Re: [PATCH v3 net-next] r8169: add support for rtl8168h(revid 0x2a)
 + rtl8211fs fiber application

On Tue, Aug 23, 2022 at 03:17:16PM +0000, Hau wrote:
> > > @@ -914,8 +952,12 @@ static void r8168g_mdio_write(struct
> > rtl8169_private *tp, int reg, int value)
> > >  	if (tp->ocp_base != OCP_STD_PHY_BASE)
> > >  		reg -= 0x10;
> > >
> > > -	if (tp->ocp_base == OCP_STD_PHY_BASE && reg == MII_BMCR)
> > > +	if (tp->ocp_base == OCP_STD_PHY_BASE && reg == MII_BMCR) {
> > > +		if (tp->sfp_if_type != RTL_SFP_IF_NONE && value &
> > BMCR_PDOWN)
> > > +			return;
> > > +
> > 
> > Please could you explain this change.
> H/W has issue. If we power down phy, then H/W will become abnormal.

Does the MAC break, or the PHY? If the PHY is the problem, the work
around should be in the PHY driver, not the MAC driver.

> > > +/* MDIO bus init function */
> > > +static int rtl_mdio_bitbang_init(struct rtl8169_private *tp) {
> > > +	struct bb_info *bitbang;
> > > +	struct device *d = tp_to_dev(tp);
> > > +	struct mii_bus *new_bus;
> > > +
> > > +	/* create bit control struct for PHY */
> > > +	bitbang = devm_kzalloc(d, sizeof(struct bb_info), GFP_KERNEL);
> > > +	if (!bitbang)
> > > +		return -ENOMEM;
> > > +
> > > +	/* bitbang init */
> > > +	bitbang->tp = tp;
> > > +	bitbang->ctrl.ops = &bb_ops;
> > > +	bitbang->ctrl.op_c22_read = MDIO_READ;
> > > +	bitbang->ctrl.op_c22_write = MDIO_WRITE;
> > > +
> > > +	/* MII controller setting */
> > > +	new_bus = devm_mdiobus_alloc(d);
> > > +	if (!new_bus)
> > > +		return -ENOMEM;
> > > +
> > > +	new_bus->read = mdiobb_read;
> > > +	new_bus->write = mdiobb_write;
> > > +	new_bus->priv = &bitbang->ctrl;
> > 
> > Please use alloc_mdio_bitbang().
> >
> I have tried to use alloc_mdio_bitbang(). But I will get error message " rmmod: ERROR: Module r8169 is in use " when I try to unload r8169.
> After debug, I found it is cause by "__module_get(ctrl->ops->owner); " in alloc_mdio_bitbang().

void free_mdio_bitbang(struct mii_bus *bus)
{
        struct mdiobb_ctrl *ctrl = bus->priv;

        module_put(ctrl->ops->owner);
        mdiobus_free(bus);
}

Make sure your cleanup is symmetrical to your setup.

     Andrew