From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marek Vasut Subject: Re: [PATCH] mdio_bus: Fix MDIO bus scanning in __mdiobus_register() Date: Fri, 29 Apr 2016 04:10:49 +0200 Message-ID: <5722C2A9.7090308@denx.de> References: <1461892155-10524-1-git-send-email-marex@denx.de> <5722BDBB.40606@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: Arnd Bergmann , "David S . Miller" , Dinh Nguyen , Sergei Shtylyov , Andrew Lunn To: Florian Fainelli , netdev@vger.kernel.org Return-path: Received: from mail-out.m-online.net ([212.18.0.9]:36325 "EHLO mail-out.m-online.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752244AbcD2CKw (ORCPT ); Thu, 28 Apr 2016 22:10:52 -0400 In-Reply-To: <5722BDBB.40606@gmail.com> Sender: netdev-owner@vger.kernel.org List-ID: On 04/29/2016 03:49 AM, Florian Fainelli wrote: > Le 28/04/2016 18:09, Marek Vasut a =C3=A9crit : >> Since commit b74766a0a0feeef5c779709cc5d109451c0d5b17 in linux-next, >> ( phylib: don't return NULL from get_phy_device() ), phy_get_device(= ) >> will return ERR_PTR(-ENODEV) instead of NULL if the PHY device ID is >> all ones. >> >> This causes problem with stmmac driver and likely some other drivers >> which call mdiobus_register(). I triggered this bug on SoCFPGA MCVEV= K >> board with linux-next 20160427 and 20160428. In case of the stmmac, = if >> there is no PHY node specified in the DT for the stmmac block, the s= tmmac >> driver ( drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c function >> stmmac_mdio_register() ) will call mdiobus_register() , which will >> register the MDIO bus and probe for the PHY. >> >> The mdiobus_register() resp. __mdiobus_register() iterates over all = of >> the addresses on the MDIO bus and calls mdiobus_scan() for each of t= hem, >> which invokes get_phy_device(). Before the aforementioned patch, the >> mdiobus_scan() would return NULL if no PHY was found on a given addr= ess >> and mdiobus_register() would continue and try the next PHY address. = Now, >> mdiobus_scan() returns ERR_PTR(-ENODEV), which is caught by the >> 'if (IS_ERR(phydev))' condition and the loop exits immediatelly if t= he >> PHY address does not contain PHY. >> >> Repair this by explicitly checking for the ERR_PTR(-ENODEV) and if t= his >> error comes around, continue with the next PHY address. >> >> Signed-off-by: Marek Vasut >> Cc: Arnd Bergmann >> Cc: David S. Miller >> Cc: Dinh Nguyen >> Cc: Florian Fainelli >> Cc: Sergei Shtylyov >=20 > Acked-by: Florian Fainelli >=20 > I had an exact same patch posted yesterday but not formally like you > did, thanks! Ah, my google-fu must be weak tonight. Thanks! >> --- >> drivers/net/phy/mdio_bus.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> NOTE: I don't quite like this explicit check , but I don't have bett= er idea now. >> >> diff --git a/drivers/net/phy/mdio_bus.c b/drivers/net/phy/mdio_bus.c >> index 499003ee..388f992 100644 >> --- a/drivers/net/phy/mdio_bus.c >> +++ b/drivers/net/phy/mdio_bus.c >> @@ -333,7 +333,7 @@ int __mdiobus_register(struct mii_bus *bus, stru= ct module *owner) >> struct phy_device *phydev; >> =20 >> phydev =3D mdiobus_scan(bus, i); >> - if (IS_ERR(phydev)) { >> + if (IS_ERR(phydev) && (PTR_ERR(phydev) !=3D -ENODEV)) { >> err =3D PTR_ERR(phydev); >> goto error; >> } >> >=20 >=20 --=20 Best regards, Marek Vasut