From: "Matt Carlson" <mcarlson@broadcom•com>
To: "Ben Hutchings" <bhutchings@solarflare•com>
Cc: "Matthew Carlson" <mcarlson@broadcom•com>,
"davem@davemloft•net" <davem@davemloft•net>,
"netdev@vger•kernel.org" <netdev@vger•kernel.org>,
"Michael Chan" <mchan@broadcom•com>
Subject: Re: [PATCH] Add ethtool to mii advertisment conversion helpers
Date: Wed, 16 Nov 2011 17:16:04 -0800 [thread overview]
Message-ID: <20111117011604.GA8683@mcarlson.broadcom.com> (raw)
In-Reply-To: <1321490078.2709.86.camel@bwh-desktop>
On Wed, Nov 16, 2011 at 04:34:37PM -0800, Ben Hutchings wrote:
> On Tue, 2011-11-15 at 14:00 -0800, Matt Carlson wrote:
> > Translating between ethtool advertisement settings and MII
> > advertisements are common operations for ethernet drivers. This patch
> > adds a set of helper functions that implements the conversion. The
> > patch then modifies a couple of the drivers to use the new functions.
>
> I like this, but:
>
> [....]
> > --- a/drivers/net/ethernet/broadcom/tg3.c
> > +++ b/drivers/net/ethernet/broadcom/tg3.c
> [...]
> > @@ -4903,23 +4880,19 @@ static int tg3_setup_fiber_mii_phy(struct tg3 *tp, int force_reset)
> > (tp->phy_flags & TG3_PHYFLG_PARALLEL_DETECT)) {
> > /* do nothing, just check for link up at the end */
> > } else if (tp->link_config.autoneg == AUTONEG_ENABLE) {
> > - u32 adv, new_adv;
> > + u32 adv, newadv;
> >
> > err |= tg3_readphy(tp, MII_ADVERTISE, &adv);
> > - new_adv = adv & ~(ADVERTISE_1000XFULL | ADVERTISE_1000XHALF |
> > - ADVERTISE_1000XPAUSE |
> > - ADVERTISE_1000XPSE_ASYM |
> > - ADVERTISE_SLCT);
> > -
> > - new_adv |= tg3_advert_flowctrl_1000X(tp->link_config.flowctrl);
> > + newadv = adv & ~(ADVERTISE_1000XFULL | ADVERTISE_1000XHALF |
> > + ADVERTISE_1000XPAUSE |
> > + ADVERTISE_1000XPSE_ASYM |
> > + ADVERTISE_SLCT);
>
> Not sure why you're renaming the variable here.
80 column character violations. By eliminating the underscore, I can
*just* make it fit.
> > - if (tp->link_config.advertising & ADVERTISED_1000baseT_Half)
> > - new_adv |= ADVERTISE_1000XHALF;
> > - if (tp->link_config.advertising & ADVERTISED_1000baseT_Full)
> > - new_adv |= ADVERTISE_1000XFULL;
> > + newadv |= tg3_advert_flowctrl_1000X(tp->link_config.flowctrl);
> > + newadv |= ethtool_adv_to_mii_1000X(tp->link_config.advertising);
>
> Doesn't this generate flow control advertising flags twice? Can the
> link_config.flowctrl and link_config.advertising fields get out of
> synch?
The tg3 driver doesn't store flow control settings through the advertising
field. I thought about changing the driver in that direction and
eliminating the tp->link_config.flowctrl field. That would be a
separate patch though.
> [...]
> > --- a/include/linux/mii.h
> > +++ b/include/linux/mii.h
> > @@ -240,6 +240,171 @@ static inline unsigned int mii_duplex (unsigned int duplex_lock,
> > }
> >
> > /**
> > + * ethtool_adv_to_mii_100bt
> > + * @ethadv: the ethtool advertisement settings
> > + *
> > + * A small helper function that translates ethtool advertisement
> > + * settings to phy autonegotiation advertisements for the
> > + * MII_ADVERTISE register.
> > + */
> > +static inline u32 ethtool_adv_to_mii_100bt(u32 ethadv)
> [...]
> > +static inline u32 mii_adv_to_ethtool_100bt(u32 adv)
> [...]
> > +static inline u32 ethtool_adv_to_mii_1000T(u32 ethadv)
> [...]
> > +static inline u32 mii_adv_to_ethtool_1000T(u32 adv)
> [...]
> > +#define mii_lpa_to_ethtool_100bt(lpa) mii_adv_to_ethtool_100bt(lpa)
>
> Shouldn't this additionally translate LPA_LPACK into ADVERTISED_Autoneg?
You mean, like this?
static inline u32 mii_lpa_to_ethtool_100bt(u32 lpa)
{
u32 result = 0;
if (lpa & LPA_LPACK)
result |= ADVERTISED_Autoneg;
return result | mii_adv_to_ethtool_100bt(lpa);
}
Yes, that looks like a better implementation.
> [...]
> > +static inline u32 mii_lpa_to_ethtool_1000T(u32 lpa)
> [...]
> > +static inline u32 ethtool_adv_to_mii_1000X(u32 ethadv)
> [...]
> > +static inline u32 mii_adv_to_ethtool_1000X(u32 adv)
> [...]
>
> I'm not convinced about the naming convention for these. Would it not
> make more sense to name them consistently by register name and signal
> type:
>
> ethtool_adv_to_mii_adv_t
> mii_adv_to_ethtool_adv_t
> ethtool_adv_to_mii_ctrl1000_t
> mii_ctrl1000_to_ethtool_adv_t
> mii_lpa_to_ethtool_lpa_t
> mii_stat1000_to_ethtool_lpa_t
> ethtool_adv_to_mii_adv_x
> mii_adv_to_ethtool_adv_x
I don't have a strong preference either way. I'll post the change along
with the above modification.
> Shouldn't there be mii_lpa_to_ethtool_1000X (or
> mii_lpa_to_ethtool_lpa_x)?
Yes. You're right. Should it just be a preprocessor definition that
points to mii_adv_to_ethtool_1000X()?
> Finally, do these need to be inline?
I don't have a strong preference here either. Phy code tends to be
slower, so there isn't really a strong performance argument. The
implementations don't seem to be so large to argue against it though.
Would you prefer they not be inlined?
next prev parent reply other threads:[~2011-11-17 1:15 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-11-15 22:00 [PATCH] Add ethtool to mii advertisment conversion helpers Matt Carlson
2011-11-16 22:36 ` David Miller
2011-11-16 22:56 ` Matt Carlson
2011-11-17 0:34 ` Ben Hutchings
2011-11-17 1:16 ` Matt Carlson [this message]
2011-11-17 1:21 ` Michael Chan
2011-11-17 1:38 ` David Miller
2011-11-17 2:29 ` Ben Hutchings
2011-11-17 1:29 ` Ben Hutchings
2011-11-17 2:06 ` Matt Carlson
2011-11-17 2:45 ` Ben Hutchings
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