From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH V2] mdio_bus: Fix MDIO bus scanning in __mdiobus_register() Date: Sun, 01 May 2016 20:50:31 -0400 (EDT) Message-ID: <20160501.205031.116469285201732756.davem@davemloft.net> References: <1462150051-6308-1-git-send-email-marex@denx.de> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, arnd@arndb.de, dinguyen@opensource.altera.com, f.fainelli@gmail.com, sergei.shtylyov@cogentembedded.com To: marex@denx.de Return-path: Received: from shards.monkeyblade.net ([149.20.54.216]:53784 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752436AbcEBAue (ORCPT ); Sun, 1 May 2016 20:50:34 -0400 In-Reply-To: <1462150051-6308-1-git-send-email-marex@denx.de> Sender: netdev-owner@vger.kernel.org List-ID: From: Marek Vasut Date: Mon, 2 May 2016 02:47:31 +0200 > Since commit b74766a0a0fe ("phylib: don't return NULL > from get_phy_device()") in linux-next, 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 MCVEVK > 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 stmmac > 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 them, > which invokes get_phy_device(). Before the aforementioned patch, the > mdiobus_scan() would return NULL if no PHY was found on a given address > 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 immediately if the > PHY address does not contain PHY. > > Repair this by explicitly checking for the ERR_PTR(-ENODEV) and if this > error comes around, continue with the next PHY address. > > Signed-off-by: Marek Vasut > Acked-by: Florian Fainelli Applied, thanks.