Messages in this thread | | | From | "Sit, Michael Wei Hong" <> | Subject | RE: [PATCH net v5 1/3] net: phylink: add phylink_expects_phy() method | Date | Wed, 12 Apr 2023 06:58:15 +0000 |
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> -----Original Message----- > From: Maxime Chevallier <maxime.chevallier@bootlin.com> > Sent: Wednesday, April 12, 2023 4:38 PM > To: Sit, Michael Wei Hong <michael.wei.hong.sit@intel.com> > Cc: Giuseppe Cavallaro <peppe.cavallaro@st.com>; Alexandre > Torgue <alexandre.torgue@foss.st.com>; Jose Abreu > <joabreu@synopsys.com>; David S . Miller <davem@davemloft.net>; > Eric Dumazet <edumazet@google.com>; Jakub Kicinski > <kuba@kernel.org>; Paolo Abeni <pabeni@redhat.com>; Maxime > Coquelin <mcoquelin.stm32@gmail.com>; Ong, Boon Leong > <boon.leong.ong@intel.com>; netdev@vger.kernel.org; linux- > stm32@st-md-mailman.stormreply.com; linux-arm- > kernel@lists.infradead.org; linux-kernel@vger.kernel.org; > linux@armlinux.org.uk; hkallweit1@gmail.com; andrew@lunn.ch; > Looi, Hong Aun <hong.aun.looi@intel.com>; Voon, Weifeng > <weifeng.voon@intel.com>; Lai, Peter Jun Ann > <peter.jun.ann.lai@intel.com>; alexis.lothore@bootlin.com > Subject: Re: [PATCH net v5 1/3] net: phylink: add > phylink_expects_phy() method > > Hello everyone, > > On Thu, 30 Mar 2023 17:14:02 +0800 > Michael Sit Wei Hong <michael.wei.hong.sit@intel.com> wrote: > > > Provide phylink_expects_phy() to allow MAC drivers to check if it is > > expecting a PHY to attach to. Since fixed-linked setups do not need > to > > attach to a PHY. > > > > Provides a boolean value as to if the MAC should expect a PHY. > > Returns true if a PHY is expected. > > I'm currently working on the TSE rework for dwmac_socfpga, and I > noticed one regression since this patch, when using an SFP, see > details below : > > > Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk> > > Signed-off-by: Michael Sit Wei Hong > <michael.wei.hong.sit@intel.com> > > --- > > drivers/net/phy/phylink.c | 19 +++++++++++++++++++ > > include/linux/phylink.h | 1 + > > 2 files changed, 20 insertions(+) > > > > diff --git a/drivers/net/phy/phylink.c b/drivers/net/phy/phylink.c > > index 1a2f074685fa..30c166b33468 100644 > > --- a/drivers/net/phy/phylink.c > > +++ b/drivers/net/phy/phylink.c > > @@ -1586,6 +1586,25 @@ void phylink_destroy(struct phylink > *pl) } > > EXPORT_SYMBOL_GPL(phylink_destroy); > > > > +/** > > + * phylink_expects_phy() - Determine if phylink expects a phy to > be > > attached > > + * @pl: a pointer to a &struct phylink returned from > phylink_create() > > + * > > + * When using fixed-link mode, or in-band mode with 1000base-X > or > > 2500base-X, > > + * no PHY is needed. > > + * > > + * Returns true if phylink will be expecting a PHY. > > + */ > > +bool phylink_expects_phy(struct phylink *pl) { > > + if (pl->cfg_link_an_mode == MLO_AN_FIXED || > > + (pl->cfg_link_an_mode == MLO_AN_INBAND && > > + phy_interface_mode_is_8023z(pl->link_config.interface))) > > From the discussion, at one point Russell mentionned [1] : > "If there's a sfp bus, then we don't expect a PHY from the MAC > driver (as there can only be one PHY attached), and as > phylink_expects_phy() is for the MAC driver to use, we should be > returning false if > pl->sfp_bus != NULL." > > This makes sense and indeed adding the relevant check solves the > issue. > > Am I correct in assuming this was an unintentional omission from > this patch, or was the pl->sfp_bus check dropped on purpose ? > > > + return false; > > + return true; > > +} > > +EXPORT_SYMBOL_GPL(phylink_expects_phy); > > Thanks, > > Maxime >
Russell also did mention: " The reason for the extra "&& !pl->sfp_bus" in phylink_attach_phy() is to allow SFPs to connect to the MAC using inband mode with 1000base-X and 2500base-X interface modes. These are not for the MAC-side of things though."
So I thought that the check can be dropped. I do not have any SFP hardware to test, if adding the check make sense, you can send us a patch so we can test it out. > [1] : > https://lore.kernel.org/netdev/ZCQJWcdfmualIjvX@shell.armlinux.o > rg.uk/
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