Messages in this thread Patch in this message | | | Subject | Re: [PATCH net-next v3 1/3] net: dp83869: Add ability to advertise Fiber connection | From | Dan Murphy <> | Date | Thu, 10 Sep 2020 12:54:36 -0500 |
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Hello
On 9/7/20 9:29 AM, Andrew Lunn wrote: > On Sat, Sep 05, 2020 at 11:17:55AM -0700, Jakub Kicinski wrote: >> On Thu, 3 Sep 2020 06:42:57 -0500 Dan Murphy wrote: >>> Add the ability to advertise the Fiber connection if the strap or the >>> op-mode is configured for 100Base-FX. >>> >>> Auto negotiation is not supported on this PHY when in fiber mode. >>> >>> Signed-off-by: Dan Murphy <dmurphy@ti.com> >> Some comments, I'm not very phy-knowledgeable so bear with me >> (hopefully PHY maintainers can correct me, too). >> >>> diff --git a/drivers/net/phy/dp83869.c b/drivers/net/phy/dp83869.c >>> index 58103152c601..48a68474f89c 100644 >>> --- a/drivers/net/phy/dp83869.c >>> +++ b/drivers/net/phy/dp83869.c >>> @@ -52,6 +52,11 @@ >>> BMCR_FULLDPLX | \ >>> BMCR_SPEED1000) >>> >>> +#define MII_DP83869_FIBER_ADVERTISE (ADVERTISED_TP | ADVERTISED_MII | \ >>> + ADVERTISED_FIBRE | ADVERTISED_BNC | \ >> I'm not actually sure myself what the semantics of port type advertise >> bits are, but if this is fiber why advertise TP and do you really have >> BNC connectors? :S > Hi Jakub > > Normally, we start with a base of ETHTOOL_LINK_MODE_TP_BIT, > ETHTOOL_LINK_MODE_MII_BIT and then use genphy_read_abilities() to read > the standard registers in the PHY to determine what the PHY > supports. The PHY driver has the ability of provide its own function > to get the supported features, which is happening here. As far as i > remember, there is no standard way to indicate a PHY is doing Fibre, > not copper. > > I agree that TP and BMC make no sense here, since my understanding is > that the device only supports Fibre when strapped for Fibre. It cannot > swap to TP, and it has been at least 20 years since i last had a BNC > cable in my hands. > > In this context, i've no idea what MII means.
I will remove the TP and BNC.
> >>> + ADVERTISED_Pause | ADVERTISED_Asym_Pause | \ >>> + ADVERTISED_100baseT_Full) >> You say 100Base-FX, yet you advertise 100Base-T? > 100Base-FX does not actually exist in ADVERTISED_X form. I guess this > is historical. It was not widely supported, the broadcom PHYs appear > to support it, but not much else. We were also running out of bits to > represent these ADVERTISED_X values. Now that we have changed to linux > bitmaps and have unlimited number of bits, it makes sense to add it.
The note in the ethtool.h says
/* Last allowed bit for __ETHTOOL_LINK_MODE_LEGACY_MASK is bit * 31. Please do NOT define any SUPPORTED_* or ADVERTISED_* * macro for bits > 31. The only way to use indices > 31 is to * use the new ETHTOOL_GLINKSETTINGS/ETHTOOL_SLINKSETTINGS API. */
Which was added by Heiner
I guess I would prefer to add this in a separate patchset once I figure out how the ETHTOOL_GLINKSETTINGS/ETHTOOL_SLINKSETTINGS API works
> >>> @@ -383,7 +389,37 @@ static int dp83869_configure_mode(struct phy_device *phydev, >>> >>> break; >>> case DP83869_RGMII_1000_BASE: >>> + break; >>> case DP83869_RGMII_100_BASE: >>> + /* Only allow advertising what this PHY supports */ >>> + linkmode_and(phydev->advertising, phydev->advertising, >>> + phydev->supported); >>> + >>> + linkmode_set_bit(ETHTOOL_LINK_MODE_FIBRE_BIT, >>> + phydev->supported); >>> + linkmode_set_bit(ETHTOOL_LINK_MODE_FIBRE_BIT, >>> + phydev->advertising); >>> + >>> + /* Auto neg is not supported in fiber mode */ >>> + bmcr = phy_read(phydev, MII_BMCR); >>> + if (bmcr < 0) >>> + return bmcr; >>> + >>> + phydev->autoneg = AUTONEG_DISABLE; >>> + linkmode_clear_bit(ETHTOOL_LINK_MODE_Autoneg_BIT, >>> + phydev->supported); >>> + linkmode_clear_bit(ETHTOOL_LINK_MODE_Autoneg_BIT, >>> + phydev->advertising); >>> + >>> + if (bmcr & BMCR_ANENABLE) { >>> + ret = phy_modify(phydev, MII_BMCR, BMCR_ANENABLE, 0); >>> + if (ret < 0) >>> + return ret; >>> + } >>> + >>> + phy_modify_changed(phydev, MII_ADVERTISE, >>> + MII_DP83869_FIBER_ADVERTISE, >>> + MII_DP83869_FIBER_ADVERTISE); >> This only accesses standard registers, should it perhaps be a helper in >> the kernel's phy code? > I suspect the PHY is not following the standard when strapped to > fibre.
No its a bit wonky in that respect.
Dan
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