Small change to ukphy

[Pyun YongHyeon]

On Wed, Apr 01, 2009 at 01:32:46AM -0600, M. Warner Losh wrote:
> I've encountered a number of PHY chips that need auto negotiation
> kicked off to come out of ISO state.  This makes sense, because the
> ukphy driver never seems to take the PHY out of isolation state
> otherwise.
> 
> Index: ukphy.c
> ===================================================================
> --- ukphy.c	(revision 190463)
> +++ ukphy.c	(working copy)
> @@ -146,6 +146,7 @@
>  	sc->mii_phy = ma->mii_phyno;
>  	sc->mii_service = ukphy_service;
>  	sc->mii_pdata = mii;
> +	sc->mii_flags |= MIIF_FORCEANEG;
>  
>  	mii->mii_instance++;
>  
> 
> This forces auto negotiation.  The reason for this is that it takes it
> out of ISO state (Isolate).  Once out of that state, things work

If the purpose is to take PHY out of isolated state couldn't this
be handled in ifm_change_cb_t handler of parent interface? I guess
the callback can reset the PHY and subsequent mii_mediachg() call
may start auto-negotiation.

> well.  The question I have is will we properly go back into ISO state
> for PHYs that should be isolated.
> 

If the PHY requires special handing for ISO state in reset it may
need separated PHY driver as ukphy(4) does not set MIIF_NOISOLATE. 
As you said it would be really great if we have a generic way to
pass various MII flags or driver specific information to mii(4).

> NetBSD has many of its NIC drivers setting this flag.  Their APIs
> allow them to set this directly at mii attach time.  Ours don't, so
> none of our drivers set this flag.
> 
> The other fix for this might be:
> Index: mii_physubr.c
> ===================================================================
> --- mii_physubr.c	(revision 190463)
> +++ mii_physubr.c	(working copy)
> @@ -113,7 +113,9 @@
>  	int bmcr, anar, gtcr;
>  
>  	if (IFM_SUBTYPE(ife->ifm_media) == IFM_AUTO) {
> -		if ((PHY_READ(sc, MII_BMCR) & BMCR_AUTOEN) == 0 ||
> +		bmcr = PHY_READ(sc, MII_BMCR);
> +		if ((bmcr & BMCR_AUTOEN) == 0 ||
> +		    (bmcr & BMCR_ISO) ||
>  		    (sc->mii_flags & MIIF_FORCEANEG))
>  			(void) mii_phy_auto(sc);
>  		return;
> 
> Which says that if auto negotiation is enabled, and ISO is set to go
> ahead and kick off an auto negotiation.  I'm less sure of this path,
> but it is an alternative.  Otherwise, we never write to the BMCR to
> take the device out of isolation.  If there's a better place to do
> this, then I'm all ears.
> 
> Either one of these hacks make several PC Cards that I have start to
> work...  In fact, I'm starting to approach 100% (up from 50%) of my
> ed-based PC Cards working with this simple change (and others to the
> ed driver).  I know that these cards are a little behind the leading
> edge, but I'd like to get them working since I've put a few hours into
> investigating things here.
> 
> Comments?
> 
> Warner