| Message ID | 201209241400.q8OE0w38011790@localhost.localdomain |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
> This patch adds proper handling of the buggy revision A2 of LXT973 phy, adding > precautions linked to ERRATA Item 4: > > Revision A2 of LXT973 chip randomly returns the contents of the previous even > register when you read a odd register regularly Does reading the PHY registers involve bit-banging an MII interface? If so this code is likely to stall the system for significant periods (ready phy registers at all can be a problem). I know some ethernet mac have hardware blocks for reading MII and even polling one MII register for changes. Maybe some of this code ought to be using async software bit-bang - especially when just polling for link status change. I'm sure it ought to be possible to do one bit-bang action per clock tick instead of spinning for the required delays. David -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Le 24/09/2012 16:13, David Laight a écrit : >> This patch adds proper handling of the buggy revision A2 of LXT973 phy, adding >> precautions linked to ERRATA Item 4: >> >> Revision A2 of LXT973 chip randomly returns the contents of the previous even >> register when you read a odd register regularly > Does reading the PHY registers involve bit-banging an MII interface? > If so this code is likely to stall the system for significant > periods (ready phy registers at all can be a problem). > > I know some ethernet mac have hardware blocks for reading MII > and even polling one MII register for changes. > > Maybe some of this code ought to be using async software > bit-bang - especially when just polling for link status change. > I'm sure it ought to be possible to do one bit-bang action > per clock tick instead of spinning for the required delays. > > David > Not sure I understand what you mean. We have been using this code without any problem for about 2 years on our Hardware. It does almost same as genphy_read_status() except that it also reads the BMCR register (which is the register preceeding the BMSR) in order to detect the unlikely happening of the bug reported by the ERRATA. In case it happens (which is really seldom), it does a re-read. We are not spinning on any delays here. Christophe -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Mon, Sep 24, 2012 at 04:00:58PM +0200, Christophe Leroy wrote: > diff -u a/drivers/net/phy/lxt.c b/drivers/net/phy/lxt.c > --- a/drivers/net/phy/lxt.c 2012-09-23 03:08:48.000000000 +0200 > +++ b/drivers/net/phy/lxt.c 2012-09-23 03:18:00.000000000 +0200 ... > @@ -175,6 +292,16 @@ > .driver = { .owner = THIS_MODULE,}, > }, { > .phy_id = 0x00137a10, > + .name = "LXT973-A2", > + .phy_id_mask = 0xffffffff, > + .features = PHY_BASIC_FEATURES, > + .flags = 0, > + .probe = lxt973_probe, > + .config_aneg = lxt973_config_aneg, > + .read_status = lxt973a2_read_status, I like this way of matching the A2 chips much better than what you had before. But are you sure this will work correctly? What do A3 chips have in the last nibble of phy_id? > + .driver = { .owner = THIS_MODULE,}, > +}, { > + .phy_id = 0x00137a10, > .name = "LXT973", > .phy_id_mask = 0xfffffff0, > .features = PHY_BASIC_FEATURES, Thanks, Richard -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Le 24/09/2012 20:30, Richard Cochran a écrit : > On Mon, Sep 24, 2012 at 04:00:58PM +0200, Christophe Leroy wrote: > >> diff -u a/drivers/net/phy/lxt.c b/drivers/net/phy/lxt.c >> --- a/drivers/net/phy/lxt.c 2012-09-23 03:08:48.000000000 +0200 >> +++ b/drivers/net/phy/lxt.c 2012-09-23 03:18:00.000000000 +0200 > ... > >> @@ -175,6 +292,16 @@ >> .driver = { .owner = THIS_MODULE,}, >> }, { >> .phy_id = 0x00137a10, >> + .name = "LXT973-A2", >> + .phy_id_mask = 0xffffffff, >> + .features = PHY_BASIC_FEATURES, >> + .flags = 0, >> + .probe = lxt973_probe, >> + .config_aneg = lxt973_config_aneg, >> + .read_status = lxt973a2_read_status, > I like this way of matching the A2 chips much better than what you had > before. But are you sure this will work correctly? Apparently it does. > > What do A3 chips have in the last nibble of phy_id? A2 chip has phy_id 0x00137a10 A3 chip has phy_id 0x00137a11 Christophe > >> + .driver = { .owner = THIS_MODULE,}, >> +}, { >> + .phy_id = 0x00137a10, >> .name = "LXT973", >> .phy_id_mask = 0xfffffff0, >> .features = PHY_BASIC_FEATURES, > Thanks, > Richard > -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tue, Sep 25, 2012 at 08:23:42AM +0200, leroy christophe wrote: > > A2 chip has phy_id 0x00137a10 > A3 chip has phy_id 0x00137a11 Okay then, thanks. Acked-by: Richard Cochran <richardcochran@gmail.com> -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
From: Richard Cochran <richardcochran@gmail.com> Date: Tue, 25 Sep 2012 09:47:36 +0200 > On Tue, Sep 25, 2012 at 08:23:42AM +0200, leroy christophe wrote: >> >> A2 chip has phy_id 0x00137a10 >> A3 chip has phy_id 0x00137a11 > > Okay then, thanks. > > Acked-by: Richard Cochran <richardcochran@gmail.com> Applied to net-next, thanks. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff -u a/drivers/net/phy/lxt.c b/drivers/net/phy/lxt.c --- a/drivers/net/phy/lxt.c 2012-09-23 03:08:48.000000000 +0200 +++ b/drivers/net/phy/lxt.c 2012-09-23 03:18:00.000000000 +0200 @@ -122,6 +122,123 @@ return err; } +/* + * A2 version of LXT973 chip has an ERRATA: it randomly return the contents + * of the previous even register when you read a odd register regularly + */ + +static int lxt973a2_update_link(struct phy_device *phydev) +{ + int status; + int control; + int retry = 8; /* we try 8 times */ + + /* Do a fake read */ + status = phy_read(phydev, MII_BMSR); + + if (status < 0) + return status; + + control = phy_read(phydev, MII_BMCR); + if (control < 0) + return control; + + do { + /* Read link and autonegotiation status */ + status = phy_read(phydev, MII_BMSR); + } while (status >= 0 && retry-- && status == control); + + if (status < 0) + return status; + + if ((status & BMSR_LSTATUS) == 0) + phydev->link = 0; + else + phydev->link = 1; + + return 0; +} + +int lxt973a2_read_status(struct phy_device *phydev) +{ + int adv; + int err; + int lpa; + int lpagb = 0; + + /* Update the link, but return if there was an error */ + err = lxt973a2_update_link(phydev); + if (err) + return err; + + if (AUTONEG_ENABLE == phydev->autoneg) { + int retry = 1; + + adv = phy_read(phydev, MII_ADVERTISE); + + if (adv < 0) + return adv; + + do { + lpa = phy_read(phydev, MII_LPA); + + if (lpa < 0) + return lpa; + + /* If both registers are equal, it is suspect but not + * impossible, hence a new try + */ + } while (lpa == adv && retry--); + + lpa &= adv; + + phydev->speed = SPEED_10; + phydev->duplex = DUPLEX_HALF; + phydev->pause = phydev->asym_pause = 0; + + if (lpagb & (LPA_1000FULL | LPA_1000HALF)) { + phydev->speed = SPEED_1000; + + if (lpagb & LPA_1000FULL) + phydev->duplex = DUPLEX_FULL; + } else if (lpa & (LPA_100FULL | LPA_100HALF)) { + phydev->speed = SPEED_100; + + if (lpa & LPA_100FULL) + phydev->duplex = DUPLEX_FULL; + } else { + if (lpa & LPA_10FULL) + phydev->duplex = DUPLEX_FULL; + } + + if (phydev->duplex == DUPLEX_FULL) { + phydev->pause = lpa & LPA_PAUSE_CAP ? 1 : 0; + phydev->asym_pause = lpa & LPA_PAUSE_ASYM ? 1 : 0; + } + } else { + int bmcr = phy_read(phydev, MII_BMCR); + + if (bmcr < 0) + return bmcr; + + if (bmcr & BMCR_FULLDPLX) + phydev->duplex = DUPLEX_FULL; + else + phydev->duplex = DUPLEX_HALF; + + if (bmcr & BMCR_SPEED1000) + phydev->speed = SPEED_1000; + else if (bmcr & BMCR_SPEED100) + phydev->speed = SPEED_100; + else + phydev->speed = SPEED_10; + + phydev->pause = phydev->asym_pause = 0; + } + + return 0; +} + static int lxt973_probe(struct phy_device *phydev) { int val = phy_read(phydev, MII_LXT973_PCR); @@ -175,6 +292,16 @@ .driver = { .owner = THIS_MODULE,}, }, { .phy_id = 0x00137a10, + .name = "LXT973-A2", + .phy_id_mask = 0xffffffff, + .features = PHY_BASIC_FEATURES, + .flags = 0, + .probe = lxt973_probe, + .config_aneg = lxt973_config_aneg, + .read_status = lxt973a2_read_status, + .driver = { .owner = THIS_MODULE,}, +}, { + .phy_id = 0x00137a10, .name = "LXT973", .phy_id_mask = 0xfffffff0, .features = PHY_BASIC_FEATURES,
This patch adds proper handling of the buggy revision A2 of LXT973 phy, adding precautions linked to ERRATA Item 4: Revision A2 of LXT973 chip randomly returns the contents of the previous even register when you read a odd register regularly Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html